U.S. patent application number 16/208228 was filed with the patent office on 2019-04-04 for enhanced ultrasound visualization of intravascular devices.
The applicant listed for this patent is Covidien LP. Invention is credited to Jan R. Lau, Robert C. Lichty, II, Monte Madsen, Rodney D. Raabe.
Application Number | 20190099171 16/208228 |
Document ID | / |
Family ID | 47558484 |
Filed Date | 2019-04-04 |
View All Diagrams
United States Patent
Application |
20190099171 |
Kind Code |
A1 |
Lichty, II; Robert C. ; et
al. |
April 4, 2019 |
ENHANCED ULTRASOUND VISUALIZATION OF INTRAVASCULAR DEVICES
Abstract
Methods and devices for providing improved ultrasound visibility
of medical devices intended for intravascular use are described.
The inclusion of gas/solid boundary regions within a medical
devices improves the resolution of the device under ultrasound
visualization. Gas/solid boundary regions may be provided through
the use of embedded gas-filled microlumens, microwells, or enclosed
pockets within the medical device.
Inventors: |
Lichty, II; Robert C.;
(Santa Rosa, CA) ; Lau; Jan R.; (Windsor, CA)
; Raabe; Rodney D.; (Spokane, WA) ; Madsen;
Monte; (Spokane, WA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Covidien LP |
Mansfield |
MA |
US |
|
|
Family ID: |
47558484 |
Appl. No.: |
16/208228 |
Filed: |
December 3, 2018 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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13553542 |
Jul 19, 2012 |
10143455 |
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16208228 |
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61510001 |
Jul 20, 2011 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
A61B 8/0841 20130101;
A61B 2017/00778 20130101; A61M 25/04 20130101; A61B 5/061 20130101;
A61B 17/12 20130101; A61M 25/0026 20130101; A61B 17/00491 20130101;
A61B 2090/3925 20160201; A61M 29/00 20130101; A61M 25/0043
20130101; A61B 2090/061 20160201; A61M 25/0108 20130101; A61B
5/02007 20130101; A61M 2025/0681 20130101; A61M 2025/0004 20130101;
A61M 25/005 20130101; A61B 17/12186 20130101; A61M 2025/1052
20130101 |
International
Class: |
A61B 17/00 20060101
A61B017/00; A61M 25/00 20060101 A61M025/00; A61B 17/12 20060101
A61B017/12; A61M 25/01 20060101 A61M025/01; A61B 5/06 20060101
A61B005/06 |
Claims
1-12. (canceled)
13. A medical device for use under ultrasound visualization, the
medical device comprising: an elongate shaft comprising an outer
surface and an inner surface defining an inner lumen, wherein the
elongate shaft comprises expanded polytetrafluoroethylene
containing enclosed gas pockets to increase the visibility of the
medical device under ultrasound imaging, and wherein the expanded
polytetrafluoroethylene is in one of (a) a closed cell
configuration or (b) an open cell configuration having an enclosing
sheath.
14. The medical device of claim 13, wherein the expanded
polytetrafluoroethylene is in the closed cell configuration.
15. The medical device of claim 13, wherein the expanded
polytetrafluoroethylene is in the open cell configuration, and
wherein the medical device comprises the enclosing sheath.
16. The medical device of claim 13, wherein the enclosed gas
pockets are disposed randomly between the outer surface and the
inner surface of the elongate shaft.
17. The medical device of claim 13, wherein the enclosed gas
pockets are irregularly distributed within the elongate shaft.
18. The medical device of claim 13, wherein the enclosed gas
pockets are disposed in a regular pattern within the elongate
shaft.
19. The medical device of claim 13, wherein the enclosed gas
pockets are disposed uniformly along a length of the elongate
shaft.
20. The medical device of claim 13, wherein the enclosed air
pockets are isolated and spaced apart from the inner lumen of the
elongate shaft.
21. The medical device of claim 13, wherein the enclosed gas
pockets comprise a width of approximately 0.1 micrometers (.mu.m)
to approximately 300 .mu.m.
22. The medical device of claim 13, wherein the enclosed gas
pockets comprise a width of approximately 1 micrometers (.mu.m) to
approximately 50 .mu.m.
23. The medical device of claim 13, wherein the enclosed gas
pockets comprise a width of approximately 5 micrometers (.mu.m) to
approximately 10 .mu.m.
24. The medical device of claim 13, wherein the enclosed gas
pockets contain air.
25. The medical device of claim 13, wherein the elongate shaft
comprises a diameter of from 3 French to 7 French.
26. The medical device of claim 13, wherein the elongate shaft
comprises a length of about 25 centimeters (cm) to about 100
cm.
27. The medical device of claim 13, wherein the elongate shaft is
configured to enable a flow of an adhesive material through the
inner lumen.
28. The medical device of claim 13, wherein the elongate shaft is
configured to at least one of couple to or extend from a syringe
configured to dispense a vein-occluding substance.
29. The medical device of claim 13, wherein the enclosed gas
pockets comprise gas-filled microspheres.
30. A system for dispensing a vein-occluding substance, the system
comprising: an elongate shaft comprising an outer surface and an
inner surface defining an inner lumen, wherein the elongate shaft
comprises expanded polytetrafluoroethylene containing enclosed gas
pockets to increase the visibility of the medical device under
ultrasound imaging, and wherein the expanded
polytetrafluoroethylene is in one of (a) a closed cell
configuration or (b) an open cell configuration having an enclosing
sheath; and a syringe configured to couple to the elongate shaft,
the syringe configured to dispense the vein-occluding substance
into the inner lumen of the elongate shaft.
31. The system of claim 30, further comprising the vein-occluding
substance.
Description
PRIORITY CLAIM
[0001] This application claims priority under 35 U.S.C. .sctn.
119(e) to U.S. Provisional App. No. 61/510,001 filed on Jul. 20,
2011, which is hereby incorporated by reference in its entirety.
This application hereby incorporates by reference in its entirety
U.S. patent application Ser. No. 12/710,318 filed on Feb. 22, 2010
and published as U.S. Pat. Pub. No. 2010/0217306 A1 on Aug. 26,
2010.
BACKGROUND OF THE INVENTION
[0002] Healthy leg veins contain valves that allow blood to move in
one direction from the lower limbs toward the heart. These valves
open when blood is flowing toward the heart, and close to prevent
venous reflux, or the backward flow of blood. When veins weaken and
become enlarged, their valves cannot close properly, which leads to
venous reflux and impaired drainage of venous blood from the legs.
Venous reflux is most common in the superficial veins. The largest
superficial vein is the great saphenous vein, which runs from the
top of the foot to the groin, where it originates at a deep
vein.
[0003] Factors that contribute to venous reflux disease include
female gender, heredity, obesity, lack of physical activity,
multiple pregnancies, age, past history of blood clots in the legs
and professions that involve long periods of standing. According to
population studies, the prevalence of visible tortuous varicose
veins, a common indicator of venous reflux disease, is up to 15%
for adult men and 25% for adult women. A clinical registry of over
1,000 patients shows that the average age of patients treated for
venous reflux is 48 and over 75% of the patients are women.
[0004] In men, the testicular blood vessels originate in the
abdomen and course down through the inguinal canal as part of the
spermatic cord on their way to the testis, where they form a
network of small veins known as the pampiniform plexus. Upward flow
of blood in the veins is ensured by small one-way valves that
prevent backflow. Defective valves or venous compression by nearby
structures can cause dilation and tortuosity of the pampiniform
plexus. This may result in a varicocele, or abnormal enlargement of
the veins in the scrotum. Like varicose veins, the presence of a
varicocele is a common indicator of venous reflux.
[0005] Venous reflux can be classified as either asymptomatic or
symptomatic, depending on the degree of severity. Symptomatic
venous reflux disease is a more advanced stage of the disease and
can have a profound impact on the patient's quality of life. People
with symptomatic venous reflux disease may seek treatment due to a
combination of symptoms and signs, which may include leg pain and
swelling; painful varicose veins; skin changes such as
discoloration or inflammation; the presence of a palpable, abnormal
mass along the spermatic cord; and open skin ulcers.
[0006] A primary goal of treating symptomatic venous reflux is to
eliminate the reflux at its source, such as, for example, the great
saphenous vein. If a diseased vein is either closed or removed,
blood can automatically reroute into other veins without any known
negative consequences to the patient.
[0007] The current non-invasive methods for treatment of reflux in
the greater saphenous vein include radiofrequency (RF) ablation,
laser endothermal ablation, and sclerotherapy, including foam
sclerotherapy. Radiofrequency ablation and laser ablation require
tumescent anesthesia which produce both bruising and pain along the
inner thigh and upper inner calf for several weeks, and both can
have side effects of burns and nerve damage. Radiofrequency
ablation and laser ablation also require capital purchases of a
radiofrequency device or laser box, often at costs of more than
$50,000, in addition to expensive disposal mechanisms. While foam
sclerotherapy is relatively non-invasive, it has a high rate of
recurrence and potential side effects. All of the methods require
wearing compression stockings for 2-4 weeks.
[0008] For those treatments which involve careful placement of a
catheter at a particular intravenous treatment site, a reliable
means for visualizing the instruments is needed. Ultrasound is a
common method for device visualization in the medical device
industry. Ultrasound works by emitting sound waves and analyzing
the waves that are reflected and returned to the ultrasound sensing
device. Despite its popularity, ultrasound visualization often
provides inadequate resolution for careful intravenous placement of
a catheter for the treatment of venous reflux disease, and improved
echogenic catheters and methods of use are needed.
SUMMARY OF THE INVENTION
[0009] Disclosed herein is a medical device for use under
ultrasound visualization. In one embodiment, the device comprises
an elongate shaft comprising an outer surface and an inner surface
defining an inner lumen, the inner lumen having an open proximal
end and an open distal end, a plurality of microlumens having
proximal ends and distal ends, embedded within the elongate shaft.
The microlumens are arranged between the inner surface and outer
surface of the elongate shaft, and they each have closed proximal
and distal ends and are configured to contain a gas within to
increase the visibility of the device under ultrasound imaging.
[0010] According to another embodiment, the device comprises an
elongate shaft comprising an outer surface and an inner surface
defining an inner lumen, and one or more microwells within the
elongate shaft, each microwell having a cross-sectional dimension
configured such that gas enters the microwell but surface tension
prevents liquid from entering the microwell. The microwells are
configured to contain gas within them to increase the visibility of
the device under ultrasound imaging.
[0011] In yet another embodiment, the medical device comprises an
elongate shaft comprising an outer surface and an inner surface
defining an inner lumen, wherein the elongate shaft comprises
expanded polytetrafluoroethylene containing enclosed gas pockets to
increase the visibility of the device under ultrasound imaging.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] FIGS. 1-11 schematically illustrate a method for occluding a
vein, such as the great saphenous vein, using a vein-occluding
substance and an imaging tool, according to one embodiment of the
invention.
[0013] FIGS. 12-16 schematically illustrate a method for occluding
a vein, such as the great saphenous vein, according to another
embodiment of the invention.
[0014] FIGS. 17-21E schematically illustrate methods for occluding
a vein, such as the great saphenous vein, according to another
embodiment of the invention.
[0015] FIGS. 22A-22D illustrate embodiments of an echogenic
catheter with embedded microlumens.
[0016] FIG. 23 illustrates an echogenic catheter with
microwells.
[0017] FIG. 24 illustrates an echogenic catheter with enclosed gas
pockets.
[0018] FIGS. 25-35 illustrate various views and components of a
vein-occluding dispensing system according to some embodiments of
the invention.
[0019] FIGS. 36-37 schematically illustrate a glue gun and adapter
assembly.
[0020] FIG. 38 schematically illustrates a front view of a glue
gun, according to one embodiment of the invention.
[0021] FIG. 39 illustrates schematically major components of a
vascular occlusion system, according to one embodiment of the
invention.
[0022] FIGS. 40A-40D illustrate various views of a vascular
occlusion device, according to one embodiment of the invention.
[0023] FIGS. 41A-41D illustrate various views of the occlusion
device of FIGS. 2A-2D in an expanded configuration.
[0024] FIGS. 42A-42B illustrate an embodiment of the frame portion
of the delivery device described above in connection with FIGS.
2A-3D with the barrier portion omitted for clarity.
[0025] FIG. 43 is a side cross-sectional view of an occlusion
device in an expanded configuration and implanted within a vessel,
according to one embodiment of the invention.
[0026] FIG. 44 is a cross-sectional view of an occlusion device in
an undeployed configuration within a delivery catheter, according
to one embodiment of the invention.
[0027] FIGS. 45-47 illustrate perspective, cross-sectional views of
an occlusion device in varying stages of deployment out of a
delivery catheter, according to one embodiment of the
invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0028] Disclosed herein are systems, methods and devices for the
minimally invasive treatment of varicose veins and other medical
conditions. When used herein with respect to the device, proximal
can refer to toward the access insertion site into a blood vessel,
while distal refers to away from the access insertion site and in
the direction of the patient. In the treatment as applied to the
greater saphenous vein, proximal may mean cephalad, or towards the
head, while distal refers to the cauda direction. In some
embodiments an occlusive device is deployed to block the saphenous
vein just distal to the Superficial Femoral Vein Junction (SFJ) and
create a flattened shape so the vein can be treated further using
either a substance to alter the vein such that blood flow is
prevented therein, such as sclerosing solution or medical adhesive.
In some embodiments, complete vein closure is the desired clinical
result of all treatments to mitigate the effects of venous
hypertension caused by retrograde venous flow. The occlusion device
and medical adhesive can be delivered through a catheter utilizing
a "single stick" method. This approach is designed to produce less
pain and fewer skin injections than used in current treatment
approaches, as well as to mitigate or eliminate the need for
patients to wear uncomfortable compression stockings after
treatment.
Vein-Collapsing Methods
[0029] Methods to treat venous insufficiency are now described, in
which the vein is compressed at least partially along the treatment
zone. Doing so can better ensure that the vein is partially or
fully collapsed as opposed to merely occluded, depending on the
desired clinical result. Not to be limited by theory, collapsing
the vein may place two or more luminal surfaces of endothelial
cells into opposing contact with each other, stimulating fibrous
tissue proliferation and resulting in improved long-term closure of
the vein with a lower risk of recanalization and vein re-opening.
In some embodiments, a deployment catheter is percutaneously
introduced into a vein at an access site, and translumenally
distally advanced across a treatment zone within a vein. External
compression is applied to collapse the vein distally of the
deployment catheter. Then the distal end of the catheter advances
to the very beginning of the occluded vein at the proximal side of
the occlusion to minimize the "trapped" blood between the catheter
and the occluded vein. After a bolus of plug forming media is
expressed from the distal end of the catheter, the occlusion at the
end of the catheter forces the vein-occluding substance to flow
retrograde (proximally) toward the catheter insertion point into
the vein and reduce the distal flow force and mixing with blood
within the vessel. This method also allows the vein-occluding media
to replace any existing blood "trapped" between the catheter and
the occluded vein and forms an occlusive plug within the vein while
minimizing mixing with the blood. This reduction in mixing can be
advantageous in certain embodiments because it can increase the
bonding strength between the vein-occluding media and the vein.
External compression distally to the treatment zone optionally may
be removed, or may remain throughout all or a portion of the
procedure. External compression can also occur around the area of
the vein where the plug forming media is expressed in order to
collapse the vein as noted above. The catheter is thereafter
proximally retracted while dispensing a vein occluding substance,
either continuously or via discrete boluses spaced apart from the
initial bolus at regular or irregular intervals across the
treatment zone. External compression can continue proximally where
the vein occluding substance is being dispensed in order to ensure
collapse of the vein as noted above. The catheter is thereafter
withdrawn, and the access site closed using conventional
techniques. The method is described in greater detail below.
[0030] The vein closure system can enter the vein such as the
greater saphenous or lesser saphenous vein or other vessel using
fluoroscopy, ultrasound, or other guidance means. A micro-catheter
system can be placed over a wire for introduction of an outer
catheter or introduction sheath into the vein. In some embodiments,
the vein is entered as distal as possible or as clinically relevant
in the abnormal vein. In some embodiments, the closure method
comprises advancement of an introducing sheath and/or dilator over
a guide wire to the sapheno-femoral junction below the
anterior-inferior epigastric vein, which in some embodiments, can
be approximately 1.5 to 2.5 cm from the sapheno-femoral junction.
Following placement of the sheath to this level and optional
verification with ultrasound, an inner catheter is introduced
through the sheath and is leer-locked or otherwise secured to the
sheath to maintain a fixed position with the tip extending
approximately 5 cm from the end of the sheath.
[0031] In accordance with FIG. 1, the occlusion method comprises
providing an injector such as a glue gun 300 that assists in
injecting a vein-occluding substance to occlude vessel 400. In some
embodiments, the distal end 302 of the glue gun 300 includes a
syringe that is operably connected to an inner catheter 204 by a
leer lock 602. A sheath or outer catheter 202 surrounds the inner
catheter 204, and assists in providing access to a target site
within the vessel 400 interior. In some embodiments, the outer
catheter 202 is introduced first followed by the inner catheter
204, while in other embodiments, the outer catheter 202 and inner
catheter 204 are introduced simultaneously. As shown in FIG. 1, the
outer catheter 202 and inner catheter 204 are introduced near the
proximal end 402 of the vessel 400 and are directed towards the
distal end 401 of the vessel, where the vein-occluding substance
will be released. In one embodiment, at the site of release of the
vein-occluding substance, the inner catheter 204 will extend beyond
the distal end of the outer catheter 202, such as by between about
3 cm and 7 cm, to prevent any vein-occluding substance from
contacting the outer catheter 202.
[0032] As shown in FIG. 1, an imaging tool such as an ultrasound
transducer 630 can also be provided that could be multifunctional,
including guiding one or more catheters, serving as a compression
element, and/or identifying areas in the interior of the vessel
that may need further occlusion or closure. In some embodiments,
the ultrasound transducer 630 can be placed into contact with an
external surface of a patient's skin prior to placing the outer
catheter 202 and/or inner catheter 204 through the vessel 400. The
ultrasound transducer 630 can assist in generating images to help
guide one or more catheters to a site where a vein-occluding
substance will be introduced. In some embodiments, the ultrasound
transducer 630 can also serve as a compression element prior to,
during or after introducing a vein-occluding substance to assist in
closure of the vessel 400. By serving as a compression element, the
ultrasound transducer can help to flatten and/or reduce the size of
the vessel 400. In some embodiments, the ultrasound transducer 630
can include a Doppler flow detection capability, and help to
identify areas in the interior of the vessel 400 that may need
further closure or occlusion and thus, further application of a
vein-occluding substance.
[0033] When the inner catheter is in position and verified with
ultrasound to be in the appropriate position below the
sapheno-femoral junction, compression at the sapheno-femoral
junction is performed and small amounts of vein occluding
substances, including liquid adhesives such as glues including
cyanoacrylates, or any substances described elsewhere herein or
known in the art, are injected into the vein. The vein can then be
collapsed using compression, such as external compression to assist
in coapting the vein and adhering the internal walls of the vein to
the vein-occluding substance in a solid, permanent bond. In some
embodiments, an additional compression device can be provided in
addition to the ultrasound transducer or probe (either proximally
or distally) to assist in collapsing the vein. In some embodiments,
the compression device can be a sequential compression device
configured to apply compressive pressure from a compressor against
the patient's limb through a flexible pressurized sleeve. The
compression can be configured to deliver uniform compression along
its length, distal-to-proximal compression in a peristaltic wave or
other modes depending on the desired clinical result. In some
embodiments, the compressive device could be configured to deliver
a pressure of at least about 30, 40, 50, 60, 70, 80, 90, 100, 125,
150, or more mm Hg, or between about 30-150 or 50-100 mm Hg in some
embodiments. In some embodiments, an external device delivering
energy to create a controlled vasospasm of the vein is used. The
energy could be, for example, electrical stimulation, cryotherapy,
infrared, visible, or UV light, microwave, RF energy, ultrasound
energy, magnetic energy, thermal energy, or a combination of the
energy sources.
[0034] In accordance with FIG. 2, the tip of the inner catheter 204
is placed at a site adjacent to the blocked or distal end 401 of
the vessel 400 with a minimum distance between them. Once the outer
catheter 202 and inner catheter are in place, the glue gun 300 can
inject a vein-occluding substance 502 that is released from the
inner catheter 204. In some embodiments, the inner catheter 204 can
release at least 1, 2, 3, 4, 5, 7, 10, 12, 15, 20, or more boluses
of vein-occluding media along a treatment site within a vein. For
example, in some embodiments, a single continuous flow of
vein-occluding media can be introduced across a treatment site,
while in other embodiments, multiple spaced-apart boluses of
vein-occluding media can be introduced at regular or irregular
intervals across a treatment site. In some embodiments, the
treatment site can be a total length of between 2 cm and 50 cm, or
between about 5 cm and 40 cm in some embodiments. Along the
treatment site, one or more boluses of vein-occluding media can be
introduced at spaced-apart intervals, such as between every 1 cm
and 7 cm, more preferably between every 3 cm and 5 cm. The
intervals need not be evenly spaced. Each bolus of media can
occlude and treat at least a portion of the treatment site. In some
embodiments, a single bolus of media can occlude and treat a length
of the vein that is between 0.5 cm to 5 cm, such that at least
about 0.5 cm, 1 cm, 2 cm, 3 cm, 4 cm, or 5 cm of the vein can be
treated. In other embodiments, the length of the treatment site
within the vein will be greater than 5 cm by a single bolus of
media. Providing one or more boluses of vein-occluding media,
particularly in selected intervals, as described herein
advantageously provides a treatment that can be performed with
greater control and ease over conventional vein-occluding processes
and which can be tailored to specific patients (e.g., having
different lengths of treatment zones).
[0035] In some embodiments, each bolus of media can have a volume
of between 0.01 to 3 cc of a vein-occluding substance (e.g.,
cyanoacrylate compound), such as between 0.01 cc to 1 cc of a
vein-occluding substance. The rate of injection can be controlled
manually, or by a mechanical and/or electronic controller
configured to release a pre-determined volume of vein-occluding
substance at a specified flow rate. While in some embodiments the
injection rate can be relatively constant throughout the procedure
in some embodiments, in other embodiments, the injection rate can
be variable, releasing periodic boluses of vein-occluding substance
at specified time and/or distance intervals. In some embodiments,
the injection rate is between 0.002 cc/sec and 6 cc/sec, such as
between about 0.02 cc/sec and 0.2 cc/sec. Controlling the volume
and flow rate of the bolus of media to levels described herein
advantageously prevents unnecessary overflow or undertreatment of
the media within the vein. In some embodiments, an injector is
provided that is configured to precisely deliver a predetermined
volume of media, such as between about 0.05 mL and 0.5 mL, or
between about 0.1 mL, and 0.2 mL, into the vein when a physician
actuates a control, such as a button, switch, dial, or foot pedal,
for example. In some embodiments, the injector includes a safety
feature, such as an electronic lockout that prevents unintended
multiple bolus injections of glue within a specified period of
time, such as, for example, requires that bolus injections be
spaced apart by at least about 0.5, 1, 2, 3, 4, 5 seconds, or
more.
[0036] In accordance with FIG. 3, once the vein-occluding substance
502 is injected out of the tip of the inner catheter 204, the
vein-occluding substance 502 flows against the distal end of the
proximal side of the occluded vessel 400 and then reverses flow
proximally traveling along the outside of the catheter track while
displacing the blood content along the target area of the vessel
400. Then, the outer catheter 202 and inner catheter 204 can be
pulled back or withdrawn to target a different site along the
vessel 400. For example, the outer catheter 202 and inner catheter
204 can be moved in a direction towards the proximal end 402 of the
vessel 400 prior to injecting additional vein-occluding substance
502 into the vessel 400.
[0037] In accordance with FIG. 4, an optional compression element,
e.g., an operator's hand 640, a sequential compression device, or
the ultrasound transducer 630 can be used to apply pressure on the
external surface of the patient's body and compress the interior
walls of the vessel 400. The optional compression element can be
used to compress portions of the vessel prior to, during or after
the introduction of the vein-occluding substance. When the
compression element compresses portions of the vessel during or
after the introduction of the vein-occluding substance, the vessel
is compressed against the vein-occluding substance 502, as shown in
FIG. 4. This compression assists in occlusion as well as collapse
of the vessel. In some embodiments, as additional portions of the
vessel are treated with the vein-occluding substance, the target
regions can be compressed immediately following, or no more than
about 5 minutes, 4 minutes, 3 minutes, 2 minutes, 1 minute, 30
seconds, 15 seconds, or less following injection of the
vein-occluding substance in some embodiments.
[0038] FIGS. 5-6 illustrate the ultrasound transducer 630 guided or
moved from a first location to a second location following
injection of the vein-occluding substance 502 at the first site.
Once the vein-occluding substance 502 is injected to a targeted
site and preferably, once the vein is completely occluded and/or
collapsed at that site, the ultrasound transducer 630 can be moved
to a second location, e.g., a location closer towards the proximal
end 402 of the vessel 400, to assist in collapse of the vessel 400
at a different site. In some embodiments, by moving the ultrasound
transducer 630 along the length of the vessel 400 in a proximal
direction, the ultrasound transducer can serve as a compression
element that provides a compression that follows the length of the
vessel 400 in a proximal direction to better ensure collapse of the
vessel. In some embodiments, the ultrasound transducer or other
external compression element can be moved a distance between the
first location to a second location spaced apart between 0.5 cm to
5 cm with respect to the first location. In other embodiments, the
ultrasound transducer can be moved a distance between the first
location to a second location that is between 3% and 50%, such as
between 3% and 20% of the total length of the treatment site.
Guiding the ultrasound transducer over a discrete distance
advantageously helps to ensure that portions of the treatment site
are effectively occluded before guiding the ultrasound transducer
over different portions of the treatment site. After moving the
ultrasound transducer 630, the glue gun 300 can inject a
vein-occluding substance 502 at the different site of the vessel
400, as shown in FIG. 6.
[0039] Once the vein-occluding substance 502 is injected into the
second site of the vessel 400, a compression element e.g., the hand
640, can once again be used to assist in collapse of the portion of
the vessel 400, as shown in FIG. 8. After achieving partial or
complete closure of a portion of the vessel 400, the ultrasound
transducer 630 can once again be guided or moved along the vessel
400 to different locations to assist in closure or occlusion of the
vessel 400, providing a moveable compression element in some
instances. With the assistance of the ultrasound transducer 630
and/or additional compression element as described above, which can
move along the length of the vessel 400 and serve as a compression
element and/or image generator, it is possible to collapse the
vessel 400 along the entire treatment length. As shown in FIG. 9,
the ultrasound transducer 630 is guided to the second location
along the vein 400 to assist in collapse of the vessel 400 at the
different location.
[0040] The application of the ultrasound probe and/or additional
compression device can be repeated at multiple locations along the
greater saphenous vein, as shown in FIGS. 10-11, until the vein is
partially or entirely co-apted and closed in a flattened state. The
inner catheter can then be removed, and a Band-Aid or other
dressing can be placed over the entrance site. In some embodiments,
the ultrasound probe can generate images that reconfirm the closure
or co-apting of the flattened vein. Once the flattened vein is
closed partially or completely, the injector is removed from the
access site, and the procedure then is completed. In one
embodiment, only a small amount of local anesthesia at the entrance
site is used. No tumescent anesthesia is required. No general or
conscious sedation is required as the procedure produces no
significant heat or other types of damage to surrounding
tissues.
[0041] While the methods above have been described with the
intention of occluding the great saphenous vein, a wide variety of
other veins, arteries, lymphatics, or other body lumens, natural or
artificial can be occluded as well using systems and devices as
disclosed herein. Furthermore, a variety of conditions can be
treated with the systems, devices, and methods disclosed herein,
for example, venous insufficiency/varicose veins of the upper
and/or lower extremities, esophageal varices, gastric varices,
hemorrhoidal varices, venous lakes, Klippel-Trenanay syndrome,
telangiectasias, aneurysms, arterio-venous malformations,
embolization of tumors or bleeding vessels, lymphedema, vascular
and non-vascular fistulas, closure of fallopian tubes for
sterilization, etc.
[0042] In some embodiments, the vein-occluding substance can be
injected into the vein using an automated process in order to
minimize undesired over-injection or under-injection of the
vein-occluding substance, injection at undesired intervals or
injection of undesired bolus sizes. For example, the outer catheter
member of the catheter can be made easily compressible (e.g., with
a thin wall). The column strength needed for catheter placement can
thus be supplied predominantly with the inner tube. Once the inner
catheter has been withdrawn from the vein, the remaining outer
catheter is filled with the vein-occluding substance. The proximal
end of the outer catheter just distally of the luer lock, manifold,
or other coupling to the vein-occluding substance injector can
carry a compression element such as a clamp, parallel rollers, or a
slideable element with the catheter extending transversely between
two portions of the slideable element. Actuating the compression
element will radially compress the outer catheter. An operator can
then hold the clamp in place while the catheter is pulled
proximally through the clamp. The clamp thus slides, rolls, or
otherwise moves along the tube, while the catheter is compressed to
precisely express the volume of the catheter as a function of the
distance the catheter is withdrawn proximally from the vein.
[0043] FIGS. 12-16 schematically illustrate a method for occluding
a vein, such as the great saphenous vein, according to one
embodiment of the invention. Ultrasonographic vein mapping,
contrast venography, or other technique, for example, can be used
prior to the occlusion procedure to better visualize a patient's
particular vascular anatomy in some embodiments. The entry site is
prepped and draped in a sterile fashion, and local anesthesia such
as Lidocaine can be provided, although may not be required. First,
the vascular system, such as a superficial vein in the foot, ankle,
or calf, for example, a dorsal digital vein, intercapitular vein,
common digital vein, dorsal venous arch, medial marginal vein,
lateral marginal vein, plantar cutaneous venous arch, or a vein of
the plantar cutaneous venous network is cannulated, such as
percutaneously or alternatively through a cut-down procedure. Any
of these veins can also be occluded using the systems and methods
described herein. Imaging such as ultrasound or fluoroscopy, for
example, can be used for access assistance. A guidewire (not shown)
can then be inserted into the vessel. A sheath or introducer, such
as a needle, can also be placed to facilitate catheter entry into
the appropriate vein. Next, a delivery catheter 200, including
inner catheter member and outer catheter member, as well as housing
an occlusion device such as described above can be inserted into
the vessel as shown in FIG. 12 via, for example, the Seldinger
technique over a guidewire. The catheter 200 is then advanced
distally into the venous system to a desired location, such as
within the great saphenous vein (or small saphenous vein or
accessory saphenous vein) as shown in FIG. 13. The inner catheter
can then be actuated relative to the outer catheter to deploy an
occlusion device 100 to its expanded configuration within the
desired location within the vein 400. The occlusion device can in
some embodiments include components as described, for example, in
U.S. Provisional Application No. 61/154,322, filed on Feb. 20,
2009, and herein incorporated by reference in its entirety,
including (but not limited to) those having tissue anchors or bars
or other features for engaging vessel walls. In some embodiments,
the occlusion device can include components as described with
respect to FIGS. 36-44. FIG. 14 illustrates the inner catheter
being advanced in preparation to deploy an occlusion device 100.
Once desired placement is confirmed, the detachment mechanism such
as a suture (not shown) is then actuated to release the occlusion
device 100 within the vessel. Deployed anchors on the frame portion
of the occlusion device 100, can prevent migration of the occlusion
device 100 from the desired location within the vein 400. Next, the
inner catheter can be withdrawn, as illustrated in FIG. 15.
[0044] After withdrawal of the inner catheter, a vein-occluding
substance such as described above can be injected through the outer
catheter into the vein 400 proximal to the deployed occlusion
device. As illustrated in FIG. 16, the outer catheter can then be
withdrawn while the vein-occluding substance continues to be
injected, in order to occlude the vein in a proximal direction
relative to the occlusion device. The outer catheter can then be
fully withdrawn, and an external compression stocking applied,
completing the procedure. Percutaneous closure methods can also be
utilized in some embodiments. In some embodiments, 0.01 cc to 1 cc
of vein-occluding substance, e.g., a cyanoacrylate compound, can be
injected over a distance of 0.5 cm to 5 cm of vein, such as at
least about 0.5 cm, 1 cm, 2 cm, 3 cm, 4 cm, or 5 cm of vein to be
treated. The injection rate can be relatively constant throughout
the procedure in some embodiments, or variable, releasing periodic
boluses of vein-occluding substance at specified time and/or
distance intervals. Withdrawal through the vein to be treated can
take place, for example, over a period of 30 seconds to 5 minutes
in some embodiments, or about equal to, or less than about 10, 9,
8, 7, 6, 5, 4, 3, 2, 1 minute, 45 seconds, or 30 seconds in some
embodiments.
[0045] A method of occluding a vein utilizing a vein-occluding
substance as an occluding member according to some embodiments will
now be described in further detail. First, a catheter can be
deployed to a desired location in a tubular structure such as a
vein as illustrated and described in connection with FIGS. 12 and
13 above. The vein 400 can then optionally be compressed, either
before or after placing the catheter, such as by, for example,
external manual compression of the leg or with a tourniquet or
other type of compression device at a distal location as shown
schematically with arrows in FIG. 17. Next, a vein-occluding
substance can be injected at a first location within the vein 400
to serve as an occluder 500, as shown in FIG. 18, to prevent
embolization more distally. External compression prior to and at a
location just distal to the injection site can advantageously help
to prevent migration of the formed in situ occluder 500 prior to
polymerization or other fixation process. Compression can also
prevent unwanted embolization distally into more central veins, as
well as induce retrograde flow of the vein-occluding substance
proximally when the vein-occluding substance, upon distal ejection
from the catheter, contacts the vein at the point that is collapsed
from compression, forcing the vein-occluding substance to flow
proximally. In some embodiments, the distance from the exit port on
the catheter where the vein-occluding substance is ejected to the
area of the vein that is collapsed from compression is no more than
about 3 cm, 2.5 cm, 2 cm, 1.5 cm, 1 cm, 0.75 cm, 0.5 cm, 0.25 cm,
or less.
[0046] The vein-occluding substance serving as an occluder 500 can
be, for example, a larger-volume bolus of a vein-occluding
substance compared to a volume of vein-occluding substance injected
more proximally over a specified period of time and/or length of
vein, of which specific ranges are described above. The initial
bolus can be at least about 0.1 cc, 0.25 cc, 0.5 cc, 0.75 cc, 1 cc,
1.5 cc, or more in some embodiments, or between about 0.05 mL and
about 0.9 mL, between about 0.05 mL and about 0.5 mL, or between
about 0.1 mL and about 0.2 mL in other embodiments The initial
bolus can be at least about 10%, 25%, 50%, 75%, 100%, 150%, 200%,
or more greater than a volume of vein-occluding substance injected
more proximally over a similar length of vein.
[0047] In addition to, or instead of a large bolus volume of
vein-occluding substance as described above, a second
vein-occluding substance with different properties than a first
vein-occluding substance used to treat the vein more proximally can
also be used as an occluder. The second vein occluding substance is
deployed first, to form the distal vein block. The first vein
occluding substance is then dispensed along the length of the
treatment site as the catheter is proximally retracted.
[0048] The second vein-occluding substance can be, for example, a
glue or other occlusive medium that expands to a greater volume,
hardens more rapidly, and/or has a shorter polymerization time
relative to the first vein-occluding substance. In some
embodiments, the second vein-occluding substance can be partially
or completely bioresorbable. If multiple different vein-occluding
substances are used, the catheter can be configured to have two or
more lumens to accommodate delivery of the different vein-occluding
substances. Alternatively the first and second occluding substances
can be deployed sequentially via a common lumen.
[0049] When the vein-occluding substance serving as a distal
occluder hardens such that a plug 500 is formed to completely
prevent blood flow distally as shown in FIG. 19, the catheter 200
can be withdrawn and the same or a different vein-occluding
substance 502 as described above can be injected along the length
of the vein segment to be treated to occlude the rest of the vein
400 to be treated while the catheter is withdrawn partially, and
fully proximally as shown in FIGS. 20-21, respectively. As
illustrated in FIG. 21, in some embodiments, 2, 3, 4, or more veins
(that may be in some cases a branch of the first vein) can be
treated during the procedure using a single puncture, or with 2, 3,
4, or more punctures.
[0050] Thus, in accordance with one implementation of the present
invention, a deployment catheter 200 is percutaneously introduced
into a vein at an access site, and translumenally distally advanced
across a treatment zone within a vein. External compression, such
as manual compression, is applied to collapse the vein distally of
the deployment catheter and create a first occlusion. A bolus of
plug forming media is expressed from the distal end of the catheter
against a proximal side of the first occlusion, to form an
occlusive plug 500 within the vein. External compression optionally
may be removed, or may remain throughout the procedure. The
catheter 200 is thereafter proximally retracted while dispensing a
vein occluding substance 502 across the treatment zone, either
continuously as a long stream, or intermittently at spaced apart
intervals, where a second occlusion in the vein can be created,
spaced apart from the first occlusion, and then a second bolus of
media is introduced against the proximal side of the second
occlusion External compression may be applied proximally, anywhere
along the length of the vein, to ensure complete filling of the
vein with the vein occluding substance 502. In some embodiments, a
second, third, or more boluses of plug-forming media are
progressively released into the vein more proximally at desired
intervals, and external compression can be applied just distal to
the point in which the catheter releases the plug forming media as
described above. The catheter 200 is thereafter withdrawn, and the
access site closed using conventional techniques.
[0051] FIG. 21A illustrates a vein 400 that is compressed distally
at point 440 to create a first occlusion, such as with external
compression. Also shown is catheter 200 with distal end 201. After
the creation of an occlusion 440 in a vein, a first volume V1
within the vein 400 can be defined between the distal end 201 of
the catheter 200 and the occlusion 440, as illustrated in FIG. 21B.
Media having a second volume V2, such as in a bolus, can then be
injected from the distal end 201 of the catheter 200 into the vein
400. In some embodiments, the second volume V2 (of the media
injected) is at least about 100%, 105%, 110%, 120%, 125%, 130%,
140%, 150%, 175%, 200%, 250%, or more of the first volume V1 (of
the vein in between the occlusion and the distal end of the
catheter), such that a proximally advancing meniscus of media V2
passes proximally past the distal end 201 of the catheter 200, as
illustrated in FIG. 21C. The catheter 200 is then withdrawn
proximally, as illustrated in FIG. 21D, and a second more proximal
occlusion 440' can be created, such as via external compression.
Media can then be injected to create a volume of media V2' greater
than the volume within the vein 400 between the distal end 201 of
the catheter 200 and the occlusion 440', as illustrated in FIG.
21E. The process can then be repeated for a total of at least 2, 3,
4, 5, 6, 7, 8, 9, 10, or more times depending on the desired
clinical result.
[0052] In some embodiments, an occlusion in a vein can be created
as described herein. A deployment catheter having a distal opening
and side wall is provided. The distal end of the deployment
catheter can be positioned within the vein at the desired location.
Media can then be introduced through e distal opening in a volume
sufficient to advance proximally around the catheter between the
sidewall of the catheter and the wall of the vein. In some
embodiments, the volume sufficient to advance proximally around the
catheter between the sidewall of the catheter and the wall of the
vein is at least about 0.05 mL, 0.1 mL, 0.2 mL, 0.3 mL, 0.5 mL, 0.7
mL, 0.8 mL, 1 mL, 1.5 mL, 2 mL, 3 mL, or more.
[0053] The distal plug 500 may be formed by a bolus of the same
material as used for the vein occluding substance 502.
Alternatively, the distal plug 500 may be formed from a material
that polymerizes more rapidly than vein occluding substance 502, or
solidifies through a mechanism other than polymerization to form an
occlusive plug. Plug 500 may alternatively be formed by a
self-expanding preformed material, such as a foam or woven or
non-woven fiber based material, which may be displaced distally
from the catheter such as by distally advancing a push wire, or
utilizing the pressure of vein occluding substance 502. The
self-expanding foam or other plug material 500 may be a
bioabsorbable material, so that no long term implant is left behind
in the body.
[0054] Proximal retraction of the deployment catheter 200 may be
accomplished in either a steady, continuous fashion, or in an
intermittent, stepped manner. Similarly, extrusion of vein
occluding substance 502 may be accomplished in a continuous manner
as the catheter 200 is proximally retracted. Alternatively, vein
occluding substance 502 may be dispensed in a plurality of bolus
ejections along the length of the treatment zone, spaced apart by a
predetermined or clinically determined distance. Spacing between
adjacent injected volumes of vein occluding substance 502 may be at
least about 0.5 cm, at least about 1 cm, at least about 2 cm, and,
in some implementations, at least about 4 cm. This procedure
minimizes the total volume of injected vein occluding substance
502, while providing a plurality of distinct bonding points along
the length of the treatment zone.
[0055] Also disclosed herein is a method of obliterating a hollow
structure, such as a vein, including the steps of reducing an
interior cross-sectional area of the hollow structure near the
obliterating site by applying a pressure to an exterior of the
hollow structure; and placing a catheter in the hollow structure
and advancing it to the obliterating site, where the obliterating
site is next to the reduced cross-sectional area. A medical
adhesive can then be injected at the obliterating site. The
interior cross-sectional area of the medical adhesive at the
obliterating site can then be reduced by compressing an exterior of
the hollow structure to form an occlusion in the hollow structure.
Compression can be achieved, for example, via an imaging probe such
as an ultrasound transducer, manual pressure, or a harness. The
medical adhesive can then solidify, forming an occlusion in the
hollow structure. The method can also include the step of
identifying an obliterating site prior to reducing an interior
cross-sectional area of the hollow structure. In some embodiments,
the catheter is removed from the obliterating site before
compression.
[0056] With any of the methods and devices described herein, a wide
variety of vein-occluding substances can be used. In some
embodiments, the substance can include an adhesive such as
cyanoacrylate, 2-octyl cyanoacrylate, and/or a sclerosing agent
such as hypertonic saline, sodium tetradecyl sulfate, chromated
glycerol, tetracycline, talc, bleomycin, or polydocanol. In some
embodiments, a cyanoacrylate can be an aliphatic 2-cyanoacrylate
ester such as an alkyl, cycloalkyl, alkenyl or alkoxyalkyl
2-cyanoacrylate ester. The alkyl group may have from 1 to 16 carbon
atoms in some embodiments, and can be a C1-C8 alkyl ester or a
C1-C4 alkyl ester. Some possible esters include the methyl, ethyl,
n-propyl, isopropyl, n-butyl, isobutyl, pentyl, hexyl, cyclohexyl,
heptyl, octyl, 2-methoxyethyl and 2-ethoxyethyl esters of
cyanoacrylic acid. Other adhesives that can be used include a
biological glue such as a bovine serum albumin-gluteraldehyde
combination (e.g., BIOGLUE, Cryolife, Atlanta, Ga.), PVA, Biogard,
collagen, fibrinogen, fibronectin, vitronectin, laminin, thrombin,
gelatin, mixtures thereof, or other biocompatible adhesives. In
some embodiments, a foam generated from, for example, one or more
of the above components can be used to enhance ablation and closure
of the vein. The viscosity and air bubble mixture can also be
controlled while taking into account the desired clinical
result.
[0057] In one embodiment, the chosen adhesive will not produce a
significant thermal effect or significant local tissue abnormal
effect, but rather produces an initial vessel co-aption/adhesion
which will withstand physiological venous pressures within the
immediate post-procedure period. Since the adhesive will not
produce a significant thermal reaction, no tumescent anesthesia is
needed. In some embodiments, the chosen adhesive induces an
inflammatory reaction which scars. The inflammatory reaction can be
followed by permanent closure of the abnormal greater or less
saphenous vein. In some embodiments, the chosen adhesive is
hardened after the first few moments (e.g., seconds or minutes) of
application and therefore, compression stockings may not be
required. With the chosen adhesive, there can be minimal or no
danger to surrounding nerves or tissue. While the amount of chosen
adhesive delivered to a target site in a vessel will vary depending
on the size of the vessel itself, in some embodiments, the amount
of adhesive or other vein-occluding substance delivered in a single
injection can be between about 0.05 mL and about 0.9 mL, between
about 0.05 mL and about 0.5 mL, or between about 0.1 mL and about
0.2 mL in other embodiments. In some embodiments, the amount
delivered in a single injection could be more than about 0.4 ML,
0.6 mL, 0.8 mL, 0.9 mL, 1 mL, or more. In some embodiments, the
amount delivered in a single injection could be less than about 0.8
mL, 0.6 mL, 0.4 mL, 0.3 mL, 0.2 mL, 0.1 mL, 0.05 mL, or less.
[0058] In some embodiments, the cyanoacrylate preparation will
contain any additives necessary to impart the desired properties to
the preparation as viscosity, color, X-ray opacity, etc. Certain
examples of additives such as thickening agents and polymerization
inhibitors are discussed further below.
[0059] In some embodiments, the chosen adhesive can also be mixed
with a thickening agent, including various cyanoacrylate polymers,
cyanoacrylate oligmers and biocompatible polymers. The
biocompatible polymers can include, for example, PLA, PLLA, PGA,
PCL, PDLLA, PLDGA, PMMA, PET, nylon, PE, PP, or PEEK, and in some
embodiments, the biocompatible polymers are soluble in a
cyanoacrylate monomer. In some embodiments, the thickening agent
can comprise glucose, sugar, starch or hydrogel. In some
embodiments, the thickening agent can also comprise various
particulates, ranging in size between about 0.001 microns to 100
microns. The particulates can be provided in dry solid form and can
disperse throughout a liquid adhesive to thicken the adhesive prior
to use. In some embodiments, the particulate comprises any of the
biocompatible polymers above, such as PLA, PLLA, PGA, PCL, PDLLA,
PLDGA, PMMA, PET, nylon, PE, PP, CAB and PEEK, while in other
embodiments, the particulate comprises a silica material with or
without an acrylic polymer. The thickening agent can assist in
providing a suitable viscosity for the adhesive as it flows through
the catheter to a target site.
[0060] In some embodiments, the chosen adhesive can also be mixed
with one or more polymerization inhibitors, which could be, for
example, an anionic or a free-radical polymerization inhibitor.
Anionic polymerization inhibitors can include soluble acidic gases
such as sulfur dioxide, or a biocompatible acid including, but not
limited to, acetic acid, sulfuric acid, sulfonic acid, hydrochloric
acid, phosphoric acid, carboxylic acid, nitric acid, or
combinations thereof. In some embodiments, the acid can be from
0.01% to about 10% by weight, such as between about 0.01% and 1% by
weight. Free-radical polymerization inhibitors include
hydroquinone, t-butyl catechol, hydroxyanisole, butylated
hydroxyanisole and butylated hydroxytoluene. The addition of one or
more polymerization inhibitors such as a biocompatible acid helps
to change the curing rate of the adhesive to prevent the adhesive
from sticking prematurely to the catheter and prevent premature
curing of the adhesive prior to binding to the vein wall. In some
embodiments, the acid helps to delay the curing and/or
polymerization of the adhesive to prevent the glue from sticking to
sections of the catheter.
[0061] One skilled in the art will appreciate that multiple
compositions of adhesive mixtures can be used in accordance with
the embodiments described herein. In one embodiment, a composition
of adhesive comprises from about 0.01 to about 50.0 weight percent
of cyanoacrylate polymer, from about 0.01 to about 50.0 weight
percent of a thickening agent selected from the group consisting of
cyanoacrylate polymer, cyanoacrylate oligmer and biocompatible
polymers, and from about 0.01 to about 10.0 weight percent of a
biocompatible acid.
[0062] In some embodiments, the adhesive can also include a
therapeutic agent such as an anti-inflammatory agent, an
anti-infective agent, an anesthetic, a pro-inflammatory agent, a
cell proliferative agent, or combinations thereof.
[0063] In some embodiments, the medical adhesives, such as the
cyanoacrylate adhesives, can have select properties. In some
embodiments, the medical adhesives can have a setting time of
between about 5 to 60 seconds. The medical adhesives can also have
a viscosity of between about 40 to 3000 cp. In some embodiments,
the viscosity could be at least about 500 cp, at least about 1,000
cp, at least about 1,500 cp, at least about 2,000 cp, at least
about 2,500 cp, or more. In some embodiments, the viscosity could
be no more than about 2,000 cp, no more than about 1,500 cp, no
more than about 1,000 cp, no more than about 500 cp, no more than
about 300 cp, or less. One skilled in the art will appreciate that
the type of adhesive is not limited to these particular
characteristics, and that other adhesives having different
properties may also be applicable.
Additional Embodiments Related to the Vein Closure System
[0064] In additional embodiments, a vein closure system is
described that does not require capital purchases for a
radiofrequency device or laser box. Simple and non-invasive methods
of using the vein closure system are provided, and in some
embodiments, the methods do not require application of a tumescent
anesthesia or wearing compression stockings. The acceptance by and
demand from patients of the vein closure system described herein
will be much higher over existing devices and techniques.
[0065] In some embodiments, the closure system comprises at least
two major components. One is a vein closure device which precisely
delivers an adhesive to the abnormal saphenous vein under
ultrasound guidance. The other component is a unique intravascular
adhesive which allows for co-aptation and closure of the abnormal
saphenous vein in a flattened, closed position. In other
embodiments, the closure system comprises three major components.
The first is a vein closure device which precisely delivers an
adhesive to the abnormal saphenous vein under ultrasound guidance.
The second is a unique intravascular adhesive which allows for
co-aptation and closure of the saphenous vein just distal to the
Superficial Femoral Vein Junction, such as within about 5 cm, 4 cm,
3 cm, 2 cm, 1 cm, or less in a flattened, closed position. The
third is a solution that can have adhesive and/or sclerosing
properties which allows for co-aptation and closure of the rest of
the saphenous vein to alter the vein such that blood flow is
prevented therein.
The Vein Closure Device
[0066] In some embodiments, the vein closure device which delivers
the vein-occluding substance, e.g., an embolic adhesive, comprises
three components. The first component is an outer catheter or
introducer sheath that allows for placement under precise
ultrasound guidance into the saphenous vein from as low a position
as possible in the greater saphenous vein or lesser saphenous vein.
The vein closure device is also configured for precise distal tip
placement into the vein to be occluded. In some embodiments, the
sheath is available in multiple size ranges and includes ID of 3
fr-7 fr and a length from 25 cm to 100 cm depending on the
placement site. In some embodiments, the sheath is echogenic under
ultrasound observation and therefore can be precisely placed below
the sapheno-femoral junction. The sheath can have multiple
graduations, as well as measurement markings that indicate
increments along the sheath, such as 0.2, 1, 2, or 5 cm increments.
The graduations and markings assist in providing precise, monitored
pull-back motions along the saphenous vein. In some embodiments, a
dilator is positioned within the introducer sheath to aid in
positioning the device at the treatment site. The dilator may have
comparatively greater stiffness than the introducer sheath. Upon
advancement to the desired treatment site, the dilator may be
removed, followed by advancement of the introduction or inner
catheter through the introducer sheath. In some embodiments, the
dilator is echogenic under ultrasound observation which may aid in
precise placement below the sapheno-femoral junction.
[0067] The second portion of the vein closure system is an
introduction or inner catheter for the vein-occluding substance or
adhesive. The inner catheter can be multiple sizes, such as from 3
fr-7 fr and include lengths of between about 25 cm to 100 cm to
match the introduction sheath size ranges. In some embodiments, the
inner catheter can be longer than the introduction sheath to allow
the inner catheter to extend from a distal end of the introduction
sheath. In one embodiment, both the inner catheter and the
introducer sheath are made of materials such as PTFE, ePTFE, PFA,
FEP, or similar polymeric materials that will provide for
negligible (if any) adhesion to the vein-occluding substance. In
some embodiments, the inner catheter has an echogenic tip that
assists in advancement through the introducer sheath. The inner
catheter can be attached to the introducer sheath, such as by luer
lock or other locking mechanism. The inner catheter protrudes from
the introduction sheath at its distal end approximately 0.5-10 cm.
and is visible under ultrasound due to its echogenic tip. The inner
catheter is used for precise delivery of a vein-occluding substance
into the vein for co-apting and occluding the vein into a flattened
configuration. In some embodiments, the outer catheter and/or inner
catheter can be coupled to or extend from a syringe designed to
dispense a vein-occluding substance.
[0068] Also disclosed herein is a medical device that can include
one, two, or more echogenic characteristics for enhanced
visualization. For example, one or more of the outer catheter, the
dilator, and the inner catheter may be echogenic in certain
embodiments, providing for improved visualization under ultrasound.
Since sound waves are reflected at junctions of differentiated
density, the greater the density difference, the brighter the
junction appears on an ultrasound visualization monitor. Since
ultrasound waves do not pass easily through gases and are mostly
reflected, the presence of gas in the path of ultrasound waves
provides for improved visualization. In certain embodiments, to
provide a high degree of visualization, the introducer sheath,
dilator, and/or the catheter may include a high degree of density
differentiation by using gas, such as air. This reflection of
ultrasound waves provides a means to visualize the location and
allow ease of placement of devices within soft tissue.
[0069] Most ultrasound visualization of medical devices involves
using metals (such as platinum marker bands or metal wire woven
extrusions) or the addition of powders (such as barium sulfate) to
extrusions to create density differences between the device and the
surrounding tissues. Using a gas, rather than a metal or powder, to
create the density differences provides several distinct advantages
in certain situations. First, gas can be orders of magnitude less
expensive than other ultrasound visualization materials of the same
given volume. Even relatively inexpensive metals, such as stainless
steel, cannot compete with the low cost of a gas, such as air.
Second, gas does not need to be processed into a particular shape;
it takes the form of whatever void it is filling. Hence it is more
pliable and retains much less embodied energy. This improves the
ease of manufacture as well as the final flexibility of the
catheter. Third, the density disparity between the gas and the
object holding and/or the surrounding tissue is typically greater
than that of other visualization methods, thereby allowing the
device to reflect more ultrasound waves and providing a clearer or
brighter image. Improved ultrasound imaging may facilitate more
accurate placement of the device to the desired treatment spot,
such as within the greater saphenous vein or other vessels as
described herein. Ultrasound can also be advantageous in not
carrying the radiation concerns inherent in, for example,
fluoroscopy. This gas/solid boundary can be created in any number
of ways. Some non-limiting examples follow.
[0070] In one embodiment, microlumens containing trapped gas may be
formed within the sidewall of the catheter. With reference to FIGS.
22A-22D, catheter 600 includes a catheter wall 602, defining a main
or central inner lumen 604, and open proximal and distal ends, or a
proximal end with at least one side port for accessing the central
inner lumen 604. In certain embodiments, a dilator or a second
inner catheter (not shown) may pass through the inner lumen 604 of
first (outer) catheter 600. In other embodiments, adhesive may flow
through the inner lumen 604 of catheter 600. Within the catheter
wall 602 are one or more microlumens 606 which run partially or
completely along the length of catheter 600. These microlumens 606
may contain air or any other trapped gas to improve ultrasound
visibility. The microlumens 606 may be sealed at the distal tip
during the tipping process, and the proximal end may be sealed,
such as with adhesive when affixing a luer lock or other connector
thereto. In other words, the microlumens could have closed proximal
as well as distal ends. Alternatively, only the distal ends may be
sealed. The proximal ends may then be left open to atmospheric
conditions. In other embodiments, gas may be delivered to the
proximal end, whereby the gas is allowed to flow distally from the
proximal end, down through the microlumens, and back out the
proximal end again. Any other mechanism which permits air to be
trapped within the microlumens may be employed. For instance,
instead of physical sealing, the microlumens may be tapered at the
distal and proximal ends such that the opening is small enough to
prevent the entry of fluids due to surface tension. As such, in
some embodiments the microlumens could be hermetically sealed, or
alternatively having openings of a diameter to allow a gas
therethrough, but that is insufficient to permit the entry of a
liquid. In alternative embodiments, the catheter may include more
than one inner lumen. For example, a configuration in which two
separate lumens are arranged within the catheter would permit the
delivery of two separate components to the delivery site, where
mixing would only occur after each of the components is dispensed
from the catheter.
[0071] Embedding the microlumens 606 within the catheter wall 602
ensures that they do not interfere with the operation of the
catheter or hinder its intravascular mobility. Any raised edge or
protruding portion on the outer surface of catheter 600 could
potentially increase the likelihood of the catheter being caught or
even causing injury to the vasculature during advancement to the
treatment site. or during retraction therefrom. Similarly, any
protrusion into the inner lumen 604 would potentially inhibit the
flow of adhesive or the passage of an inner catheter therethrough.
Since embedding the microlumens 606 within the wall 602 maintains
both a smooth outer surface and a smooth inner surface, these
potential problems may advantageously be avoided.
[0072] In certain embodiments, the catheter 600 may include one
microlumen 606. Other embodiments may include two, three, four,
five, six, or more microlumens embedded within the catheter wall
602. According to some embodiments, the microlumens may run
parallel or substantially parallel to the main inner lumen 604
and/or the catheter sidewall 602. In other embodiments, the
microlumens may be oriented in another configuration. For instance,
the microlumens may spiral helically around the catheter 600, or
may form a zigzag pattern along its length. Other configurations
are also possible.
[0073] As shown in FIG. 22A, in certain embodiments a plurality of
microlumens 606 may be arranged such that they are equally spaced
radially within the catheter wall 602. In other embodiments, the
microlumens may be arranged in irregularly, or in clusters, as
shown in FIG 22B. The catheter may be formed of any desired
material. For instance, the catheter may be formed from a plastic
such as polytetrafluorethylene (PTFE), stainless steel, or other
material.
[0074] The use of a gas/solid boundary may also be combined with
other techniques for improving ultrasound visibility. For instance,
as shown in FIG. 22C, a wire 608 that could be made of a metal may
be located within each gas-filled microlumen 606. The
cross-sectional diameter of the microlumens may vary. For example,
in various embodiments, the diameter of the microlumens may be
about or less than 50 .mu.m, 100 .mu.m, 150 .mu.m, 200 .mu.m, 250
.mu.m, or more. In some embodiments, the diameter of the
microlumens may be about or more than about 250 .mu.m, 200 .mu.m,
150 .mu.m, 100 .mu.m, 50 .mu.m, or less. In certain embodiments,
each microlumen 606 includes a thin metal wire 608 located within
it, the wire 608 having an outer diameter that about or no more
than about 90%, 80%, 70%, 60%, 50%, or less of the diameter of the
microlumen. In other embodiments, some but not all of the
microlumens 606 include metal wires 608 located within. The metal
wires 608 may be placed within previously existing microlumens 606,
or alternatively the catheter tubing may be extruded directly over
the metal wires 608 to enclose them within the microlumens. The
metal wire 608 may extend along the entire length of the microlumen
606. Alternatively, the metal wire 608 may only extend along a
portion of the microlumen 606,
[0075] In some embodiments, the length of the metal wire 608 varies
from one microlumen to the next. For instance, a first microlumen
may contain a metal wire 608 of a first length. A second microlumen
may contain a metal wire 608 of a second length longer than the
first length. A third microlumen may contain another metal wire 608
that is longer than the second, and so forth. In certain
embodiments, the lengths of the metal wires may be offset from one
another by a uniform amount. For instance, a one metal wire may
extend the full length of the catheter, while the next metal wire
terminates 1 cm short of the distal tip. Another metal wire may
terminate 2 cm short of the distal tip, and so forth. The
arrangement of several metal wires of subsequently shorter lengths
may advantageously provide a means for determining more precisely
the location of the catheter within the body. This configuration
may aid in determining the position of the catheter within the
body.
[0076] With reference to FIG. 22D, at least a portion of the
catheter sidewall 602 may include first see-through (e.g.,
transparent or translucent) sections 607 and second opaque sections
609 (in the lower cross-section A-A of the view of catheter 600 in
the upper part of FIG. 22D). Providing see-through sections 608 may
allow the physician to view fluid within the lumen 604. A series of
indicia, e.g., laser markings 611 may be disposed at one, two, or
more locations along the axial length of the catheter. The opaque
section 609 can provide improved visibility of the markings 611. In
various embodiments, the opaque sections 608 can comprise, for
example titanium dioxide or a material having a desired color. The
laser markings 611 can be spaced apart at regular or irregular
intervals permitting the user to judge distances. In some
embodiments, the laser markings 611 can be spaced at regular
intervals, for example every 3 cm, every 5 cm, or more which can be
advantageous in determining locations to release a bolus of a
substance within a body lumen. In various embodiments, the laser
markings 611 can be spaced irregularly. For example, in the
illustrated embodiment, the distal-most laser marking 611 is
positioned 3 cm from the distal tip 613, and the second laser
marking 611 is positioned 85 cm from the distal tip 613, which can
be advantageous positioning, for example, at an appropriate
starting location for a procedure to coapt a vein such as the
saphenous vein.
[0077] With continuing reference to FIG. 22D, the catheter 600 may
be outfitted with an atraumatic distal tip 613, which includes an
opening of the lumen 604. As described above, in various
embodiments some or all of the microlumens 606 may also be open at
the distal tip 613. In other embodiments, some or all of the
microlumens 606 may be sealed at the distal tip 613. The catheter
600 also includes a strain relief 615, which is adjacent to the
proximal hub 617. The hub 617 comprises one or more input ports
which can include spin locks. In some embodiments, the spin lock
can be a Luer lock consistent with ISO prescribed dimensions, for
example as described in ISO 594-1 (First Edition 1986-06-15) and
ISO 594-2 (Second Edition 1998-09-01), both of which are hereby
incorporated by reference in their entireties. Various other
configurations for the hub 617 are possible. For example, the input
port could be on the proximal end of the hub 617 as shown coaxial
with the longitudinal axis of the catheter. In some embodiments,
one or more input ports could be longitudinally offset from the
longitudinal axis of the catheter, such as at an angle to the
sidewall of the hub.
[0078] In another embodiment, a gas/solid boundary may be provided
via small holes in a direction either normal or oblique to the
longitudinal axis of the catheter. The apertures form microwells
that are large enough to hold gas within, but small enough to
prevent fluids from entering the hole due to surface tension. As
such, a meniscus 612 naturally forms at the boundary of gas and
liquid at the surface of the microwell 610. The gas trapped within
each microwell provides for increased ultrasound visibility. In
exemplary embodiments, the microwells are configured such that gas
is retained therein when the catheter is submerged within whole
blood. For example, the microwells may be dimensioned so that
surface tensions between about 30.times.10.sup.-3 N/m and
80.times.10.sup.-3 N/m, or about 50.times.10.sup.-3 N/m and
64.times.10.sup.-3 N/m prevent liquids from entering the
microwells. With reference to FIG. 23, microwells 610 are drilled
into the surface of catheter 600. The microwells may be formed by
mechanical drilling, laser drilling, chemical etching, or any other
means. The microwells may extend partially through the catheter
wall 602. In other embodiments, the microwells may extend
completely through the catheter wall 602. The microwells 610 may
have a cross-section that is circular, elliptical, rectangular,
irregular, or any other shape, so long as the surface tension
prohibits any, or substantially any liquid, whether bodily fluids
or adhesives, from entering the microwell 610. In some embodiments,
the cross-sectional area of the microwells may range from 1
.mu.m.sup.2 to 1 mm.sup.2, from 50 .mu.m.sup.2 to 750 .mu.m.sup.2,
or from 100 .mu.m.sup.2 to 500 .mu.m.sup.2. In certain embodiments,
the cross-sectional area of the microwells may be 1 .mu.m.sup.2, 5
.mu.m.sup.2, 10 .mu.m.sup.2, 25 .mu.m.sup.2, 50 .mu.m.sup.2, 100
.mu.m.sup.2, 500 .mu.m.sup.2 or more. In other embodiments, the
cross-sectional area of the microwells may be 500 .mu.m.sup.2, 100
.mu.m.sup.2, 50 .mu.m.sup.2, 25 .mu.m.sup.2, 10 .mu.m.sup.2, 1
.mu.m.sup.2, or less.
[0079] The microwells 610 may be arranged radially in a regular
pattern. For instance, the microwells 610 may be spaced equally
radially around the catheter 600. Alternatively, the microwells 610
may be arranged in clusters or irregularly radially around the
catheter 600. In addition to the radial orientation, the
longitudinal spacing of the microwells may be varied. For instance,
the microwells may be oriented in groups arranged circumferentially
and spaced apart longitudinally by equal distances. In this
configuration, each ring of microwells surrounds the catheter at a
given location, and is spaced apart from the longitudinally
adjacent ring of microwells by a particular distance. In certain
embodiments, the longitudinal distance between adjacent rings of
microwells may vary to provide location identification.
[0080] In some embodiments, the microwells may have identical
sizes. In other embodiments, the cross-sectional dimensions may
vary, as may the depth.
[0081] In still another embodiment, a gas/solid boundary may be
firmed via enclosed gas pockets, whether random or otherwise,
within the wall of the catheter 600. For instance, as shown in FIG.
24, the catheter may be manufactured with closed cell expanded PTFE
(ePTFE), which will contain pockets of air 612 within it, the air
pockets being isolated and spaced apart from the central lumen of
the catheter. Alternatively, open cell ePTFE may be used in
conjunction with an enclosing sheath. Methods of manufacturing
ePTFE are well known in the art. Due to its natural resistance to
adhesion, ePTFE may facilitate the unimpeded flow of adhesive
material through the lumen to the treatment site. The use of
enclosed air pockets is not limited to ePTFE, however, but rather
any suitable expanded plastic or other material that contains
enclosed pockets of air may be used, such as an open or closed cell
material, including a sponge material. Additionally, in some
embodiments differing materials are used as an outer sheath. One
way of accomplishing this would be through the manufacture of
closed cell ePTFE or open cell ePTFE with an enclosing sheath.
[0082] The enclosed gas pockets may be formed within any suitable
material within the catheter. For instance, in some embodiments, a
polymer containing gas-filled microspheres may be used to
manufacture the catheter. In other embodiments, gas or foaming
agents may be injected into a polymer, such as polyurethane, to
form a polymeric layer with enclosed gas pockets. Chemical foaming
agents that could be added to the plastics material include
azocarbonomides, dinitrosopentmethelyene-tetramine,
benzenephonohydrazine, 4,4 oxybis(benzenephonohydrazine),
NN.sup.1dimethyl-NN.sup.1dinitrosoterephthalamide,
azoisobutyronitrile, sodium bicarbonate, terephthalazide or
trihydrazinatrazine. Another way of forming the gas pockets would
be by incorporating a liquid into the plastics melt which volatizes
during the melt process. Alternatively, solid powdered dry ice
(carbon dioxide) could be incorporated into the melt so that the
particles of dry ice become gas pockets during the forming process.
It could be possible to use other solids which undergo sublimation
in this way. The gas pockets could be formed directly as a result
of chemical reaction during polymerisation and or alternatively
during cross-linking. The gas pockets could be formed mechanically
by whipping the plastics in a liquid form, such as in the manner
used to form latex foam. Alternatively, small particles of a
soluble material could be added to the plastics melt and
subsequently dissolved away.
[0083] A protective sheath may surround a polymer with enclosed gas
pockets to define the catheter, or in other embodiments no such
sheath is required.
[0084] The gas pockets in some embodiments extend in a continuous
or discontinuous region along the length of the device. The gas
pockets may have a dimension, such as a width of between 0.1 .mu.m
to 300 .mu.m, between 1 .mu.m and 50 .mu.m, or between 5 .mu.m and
10 .mu.m. In some embodiments, the width of the gas pockets are 0.1
.mu.m, 5 .mu.m, 10 .mu.m, 50 .mu.m, 300 .mu.m, or more. In other
embodiments, the width of the gas pockets are 300 .mu.m, 50 .mu.m,
10 .mu.m, 5 .mu.m, 0.1 .mu.m, or less. In certain embodiments, the
enclosed gas pockets are distributed uniformly along the length of
the device. In other embodiments, the enclosed gas pockets may be
patterned, irregularly distributed, or otherwise within the
device.
[0085] In each of these aforementioned non-limiting examples, the
inclusion of gas regions within the catheter provides for multiple
gas/solid boundary regions. As discussed above, each of these
boundaries allows for improved ultrasound visibility. With greater
visibility and heightened resolution, the location of the catheter
within the body may be accurately determined. In particular the use
of such an echogenic catheter may advantageously facilitate precise
placement below the sapheno-femoral junction for use in the
treatment of venous reflux, such as for injection of an adhesive
composition at one, two, or more locations within the vein for
example.
Glue Gun and Adapter
[0086] The third portion of the vein closure system is the glue gun
or other adhesive introducing device that attaches to the inner
catheter. In some embodiments, the adhesive introducing device is a
manual liquid dispenser gun that can dispense an adhesive into a
vessel with control and accuracy. One such dispenser gun is
disclosed in U.S. Pat. No. 6,260,737 to Gruendeman et al., which is
incorporated by reference herein in its entirety. Other embodiments
of the glue gun are discussed in more detail below.
[0087] Additional embodiments are provided that are directed to a
vein-occluding substance dispenser adapter, such as a glue gun, and
associated components. In some embodiments, a glue gun is provided
that is mateably attachable to a dispensing catheter or syringe by
an adapter. The adapter can advantageously convert, for example, a
conventional industrial glue gun for medical use, such as described
herein while being properly sterilized as well.
[0088] FIGS. 25-35 illustrate a glue gun system configured to
assist in the dispensation of a vein-occluding substance, according
to some embodiments of the invention. FIG. 25 illustrates a side
view of a glue gun and adapter system including an adapter 1, a
glue gun 2, and a plunger 3 according to one embodiment. The
adapter 1 includes an adapter lock end 4 with collars or flanges 25
that allow the adapter 1 to be fixed to the glue gun 2 via a
holding segment 33. The adapter 1 further includes a syringe lock
end 5 that allows the adapter 1 to be fixed to a syringe 36.
[0089] The glue gun 2 includes a handle 31 and a pull trigger 12.
The pull trigger 12 is used in connection with internal mechanisms
of the glue gun 2 (shown in FIGS. 36 and 37 and described further
below) and the plunger 3 to provide controlled dispensation of a
vein-occluding substance through syringe 36.
[0090] The plunger 3 comprises a solid rail-like segment that
extends from outside the body of the glue gun 2 and through the
internal body of the glue gun 2. The plunger 3 includes teeth that
work in conjunction with a spring pawl mechanism (shown in FIG. 37)
to lock the position of the plunger 3 and provide controlled
dispensation of glue. The distal end of the plunger 3 makes contact
with the proximal end of the syringe 36 such that the plunger 3 is
capable of pushing the syringe to dispense a vein-occluding
substance such as an adhesive.
[0091] FIG. 26 illustrates a perspective view of the adapter 1 in
FIG. 25. The adapter 1 includes an adapter lock end 4, a syringe
lock end 5, a holding slot 6 and a hollow body 7.
[0092] The adapter lock end 4 includes one or more collars or
flanges 25 that are receivable into a holding segment of the
dispenser gun upon rotation. The adapter lock end 4 is configured
such that upon rotation of the adapter 1, the flanges 25 are
received in and secured in the holding segment 33. In addition, the
adapter lock end 4 includes an opening or slot (shown in FIG. 28)
through which the distal end of the plunger 3 can be inserted.
[0093] The syringe lock end 5 includes a holding slot 6 for
receiving a syringe 36 and an opening 41 through which the plunger
3 can pass. As shown in FIG. 26, the holding slot 6 is shaped like
a barrel-wing. To secure a syringe to the syringe lock end 5, a
proximal end of a syringe can be introduced into the holding slot
6. In some embodiments, the proximal end of the syringe can be
barrel-wing shaped such that when the syringe is introduced to the
syringe lock end 5, the syringe comes into contact with walls 34 of
the holding slot 6. The syringe can then be rotated so that it is
securely received in the holding slot 6. One skilled in the art
will appreciate that the holding slot 6 and the proximal end of the
syringe need not be shaped similarly. Nor is it necessary for the
holding slot 6 to be barrel-wing shaped; any shape is suitable so
long as it can receive a syringe end prior to rotating and securing
of the syringe.
[0094] The hollow body 7 of the adapter 1 is designed to receive
the syringe plunger 3 as it moves transversely substantially along
a longitudinal axis of the hollow body 7 during injection. In some
embodiments, the length of the hollow body 7 of the adapter is
between 2 and 5 inches. The hollow body can be circular, elliptical
or any other shape suitable for receiving the plunger 3. The
diameter of the hollow body 7 can be, in some embodiments, between
0.5 and 1.1 inches.
[0095] FIG. 27 illustrates a front perspective view of the adapter
1 in FIG. 25, including the opening 41 through which the plunger 3
can be received. Also shown are walls 34 of the syringe lock end 5.
The walls 34 are shaped such that upon initial entry of a syringe
into the syringe lock end 5, surfaces of the syringe 36 are placed
into contact with the walls 34. Upon rotation of the syringe 36,
the syringe 36 can be locked into place in the holding slots 6.
[0096] FIG. 28 illustrates a rear perspective view of the adapter 1
in FIG. 25, including the adapter lock end 4 and flanges 25
receivable in the holding segment 33 of dispenser gun 2. Also
illustrated is hole or opening 9 through which the plunger 3 can
pass during the injection of vein-occluding substance.
[0097] FIG. 29 illustrates a cross-sectional view of the adapter 1
and its hollow body 7. From this view, it is possible to see the
adapter 1 as having at least two separate diameters, an inner
diameter (formed at the openings to the hollow body 7) and an outer
diameter (formed in the hollow body 7 itself). In some embodiments,
the inner diameter is between 0.5 and 0.9 inches, while the outer
diameter is between 0.7 and 1.1 inches.
[0098] FIG. 30 illustrates a side view of a glue gun system
including an adapter 1, a glue gun 2, and a plunger 3 according to
another embodiment. The system includes an adapter lock end 4 and a
syringe lock end 5 having a syringe 36 attached thereto. In
contrast to the system in FIG. 25, the glue gun system in FIG. 30
does not include an adapter lock end 4 having an exposed collar or
flange that is placed in a holding segment of the gun 2. Instead,
the adapter lock end 4 includes a flange 25 (shown in FIG. 32) that
mates with the glue gun 2 and remains unexposed upon final
assembly.
[0099] FIG. 31 illustrates a side view of the glue gun and adapter
system of FIG. 30 including the adapter 1, the glue gun 2, the
plunger 3, and in addition, a delivery catheter 200. In some
embodiments, the delivery catheter 200 includes an outer catheter
surrounding an inner catheter. The delivery catheter 200 extends
from the distal tip of the syringe 36 and is designed to provide
access to a target site within a vessel interior.
[0100] FIG. 32 illustrates a perspective view of the adapter 1 in
FIG. 30 having an adapter lock end 4, a syringe lock end 5, a
hollow body 7 and a fit-in notch 8 located near the adapter lock
end 4. The fit-in notch 8 is capable of receiving a mateable collar
or flange located on the glue gun 2 that will lock the adapter 1 to
the glue gun 2 upon rotation of the adapter.
[0101] FIG. 33 illustrates a front perspective view of the adapter
1 of FIG. 30, including the syringe lock end 5. An opening 41
located on the syringe lock end 5 is also shown. The opening 41,
which is configured to receive a dispenser plunger 3, is T-shaped
in some embodiments, although single slit, "I", arcuate, or other
shaped openings are also possible. The advantage of the T-shaped
opening 41 is that it can provide better guidance for a dispenser
plunger 3 that is received through the syringe lock end 5, as the
T-shaped opening provides specific paths along the "T" shape for
the plunger 3 to move. The T shape can also add strength to the
plunger 3, such as in the longitudinal direction, for more
efficient dispensing. The T shape also could add stability to the
plunger 3 in the transverse direction to increase its buckling
strength so that it will be less likely to buckle during the
dispensing of high viscosity materials.
[0102] FIG. 34 illustrates a rear perspective view of the adapter 1
of FIG. 30, including the adapter lock end 4. The adapter lock end
4 includes its own T-shaped opening 9, similar to the T-shaped
opening 41 in the syringe lock end 41, through which dispenser
plunger 3 can pass.
[0103] FIG. 35 illustrates a cross-sectional view of the adapter 1
of FIG. 30 and its hollow body 7. The adapter 1 includes a central
lumen 7 with open proximal and/or distal ends and designed to allow
the syringe plunger 3 to move through during the injection process.
The adapter 1 also can optionally include one, two, or more side
lumens 10 defined between walls 70 and 72, which can provide the
adapter 1 with a reduced weight, which can be beneficial in some
circumstances. In some embodiments, the side lumens 10 define a
closed free space volume that is at least about 10%, 20%, 30%, 40%,
50%, 60%, 70%, 80%, 90%, or more of the entire enclosed volume
between walls 70, 72. By providing an adapter with reduced weight,
this allows for improved handling, reduced weight, and cost
efficiencies for manufacturing purposes. In other embodiments, the
adapter 1 can include regions besides or in addition to the second
hollow space 10 that are removed or cut-out of the adapter 1 to
provide additional weight reduction.
[0104] FIG. 36 illustrates an adapter 1 and glue gun 2 prior to
assembly. In some embodiments, the glue gun 2 includes extensions
66 that enclose an open space 67 for receiving the adapter lock end
4 of the adapter 1. While the adapter lock end 4 is placed in the
open space 67, the extensions 66 of the glue gun 2 enclose the
fit-in notch 8 of the adapter 1, thereby forming a secure
connection between the adapter 1 and glue gun 2, as shown in FIG.
37.
[0105] FIG. 37 illustrates the adapter 1 and glue gun 2 of FIG. 36
following assembly. Included in the assembly within the hollow body
17 of the glue gun are plunger 3 with teeth 16, stopper 11, spring
mechanism 15 including spring pin 13 and spring pawl 14, plunger
release button 18, floating gripper 19, plunger pocket 20 and
spring stop 21.
[0106] As shown in FIG. 37, the assembly includes a glue gun 2
having a trigger 12 for controlling the dispensation of glue from
the gun. The trigger 12 of the glue gun is integrated with the gun
body by a spring pin 13, which is part of a spring mechanism 15.
The spring mechanism 15 also includes a spring pawl 14 designed to
interact with teeth 16 of the plunger 3 to precisely lock the
position of the plunger. Movement of the spring pawl 14 is
controlled by the trigger 12. Upon pressing or clicking of the
trigger, the spring pawl 14 is adjusted to allow one or more teeth
16 of the plunger 3 to move forward through the adapter 1 and press
against a syringe (not shown) to dispense a glue or adhesive. To
prevent the rearward movement of the plunger 3 after clicking the
trigger, a floating gripper 19 is provided that engages with the
plunger 3 to stop rearward movement by frictional force. Plunger
pocket 20 can allow movement (both forward and backward) of
floating gripper 19 in the pocket. During the forward movement of
the plunger 3, the floating gripper 19 moves with the plunger 3
(because of the friction between them) assisted by the plunger
pocket 20. After the trigger is released and the plunger 3 (with
the floating gripper 19) moves backward, the plunger pocket 20 sets
the limit for the movement of the plunger 3. The plunger release
button 18 allows the disengagement between the plunger 3 and the
spring pawl 14. Pushing the plunger release button 18 will move the
spring pawl 14 downward and release the plunger 3 from the spring
pawl 14. Then the plunger 3 will be free to move in either backward
or forward directions.
[0107] To limit the effect of the spring mechanism 15 and restrict
the forward displacement of the plunger teeth 16, the spring
mechanism 15 is accompanied by a stopper 11. The stopper 11 serves
as a physical barrier to the movement of the spring mechanism,
thereby providing for greater control over dispensation of the glue
or adhesive.
[0108] FIG. 38 is a front view of the glue gun 2 that illustrates
the gun hollow body 17. Among the mechanisms within the gun hollow
body 17 includes the plunger 3, which is displaced within the
hollow body by the pull of the gun trigger.
[0109] The embodiments of the glue gun system described in FIGS.
25-38 are designed to deliver precise amounts of adhesive or
similar vein-occluding substance and can be used with the methods
described above. By providing greater control over the dispensation
of vein-occluding substance, such as by using a spring mechanism 15
including spring pawl 14 and stopper 11, the glue gun system can
deliver the vein-occluding substance continuously or in discrete
injectable quantities, such as 0.1 ml to 1.0 ml per injection,
thereby advantageously reducing the risk of overflow and
back-clogging of the delivery system. The amount of vein-occluding
substance used can depend on the size of the vein, the compression
pressure, and surrounding environment. The glue gun will allow for
exact increments of adhesive to be extruded or discharged from a
catheter. This will allow a vein to be sealed shut at multiple
sites along its length.
Deployable Occlusion Device
[0110] Embodiments are now described that relate to components of a
venous occlusion system comprising a deployable occlusion device.
FIG. 39 schematically illustrates components that can be used in a
venous occlusion system, according to one embodiment of the
invention. The system can include, for example, a deployable
occlusion device 100 for insertion into a desired location within a
vein; a catheter 200 which can be a tubular member for delivering
the occlusion device 100 as well as serving as a conduit for
delivery of one or more substances for closing the vein; and an
injector 300 that can be coupled to the catheter 200 and actuating
the substance into the vein via the catheter.
[0111] FIGS. 40A-40D illustrate various views of one embodiment of
a vascular occlusion device 100, according to one embodiment of the
invention. Although certain particular embodiments of an occlusion
device will be described in detail herein, one of skill in the art
will appreciate that any of a variety of occlusion devices can be
utilized in the system of the present invention. In some
embodiments, the occlusion device can be transformable from a
first, reduced cross-sectional configuration for transluminal
advance to the deployment site, to a second, radially enlarged or
transversely enlarged configuration for occluding the vein.
Transformation from the reduced configuration to the enlarged
configuration can be accomplished in a generally radially
symmetrical fashion, or in an elliptical, or planar fashion, each
of which can accomplish the result of achieving localized closure
of the tubular structure such as a vein in which the device is
deployed. However, in some embodiments, the occlusion device 100
can be a vein-occluding substance, e.g., a bolus of glue, as will
be described further below.
[0112] Transformation of the occlusion device may be accomplished
in any of a variety of ways, such as by releasing a restraint on a
frame which is biased in the direction of the enlarged
configuration. Alternatively, the occlusion device may be
transformed to the enlarged configuration under active force, such
as by axial shortening to achieve radial expansion. As a further
alternative, occlusion devices for use with the system of the
present invention may include detachable inflatable balloons, open
cell or closed cell foam, sponge, embolic coil meshes having either
a randomized or predetermined pattern, or other structures
depending upon the desired clinical performance. The occlusion
device may be provided with one or two or more tissue anchors or
barbs, for engaging the vessel wall, or other anti-migration
surface features such as a roughened or adhesive surface, and/or
enhanced surface area for contact with the vessel wall in a manner
sufficient to inhibit migration.
[0113] FIG. 40A is a perspective view of an occlusion device 100
that includes a frame portion 102 and a barrier portion 106. The
occlusion device is shown in a reduced, low crossing profile
configuration for delivery, such as within a catheter 200. The
frame portion 102 as shown has a proximal end 103 and a distal end
105, and can include at least 2 or 3 or 6 or 8 or more
interconnected struts 106 as shown.
[0114] The frame 102 may have a wide variety of wall patterns
depending on the desired clinical result, or have a continuous
sidewall in some embodiments. In the illustrated embodiment, the
wall pattern comprises a generally sinusoidal framework including a
plurality of proximally facing apexes 112 and distal apexes 110
interconnected by a plurality of struts 114. This can be clearly
seen, for example, in FIG. 42B.
[0115] The frame portion 102 can be made of a metal, such as
stainless steel, or a shape memory material such as, for example,
nitinol or elgiloy. However, in some embodiments, the frame portion
102 may be made of a shape memory polymer or biodegradable
material, such as, for example, poly(alpha-hydroxy acid) such as
poly-L-lactide (PLLA); poly-D-lactide (PDLA), polyglycolide (PGA),
polydioxanone, polycaprolactone, polygluconate, polylactic
acid-polyethylene oxide copolymers, modified cellulose, collagen,
poly(hydroxybutyrate), polyanhydride, polyphosphoester,
poly(amino-acids), or related copolymers. In some embodiments, the
frame portion 102 can be laser-cut out of a tube. If the frame
portion 102 is biodegradable, it can be configured to fully degrade
over a period of time depending on the desired clinical result and
the properties of the vein-occluding substance (e.g., hardening or
polymerization time of a glue), such as, for example, less than
about 1 year, 6 months, 3 months, 1 month, 2 weeks, 1 week, 3 days,
1 day, 12 hours, 6 hours, 3 hours, or less.
[0116] The barrier portion 104 can be sized, shaped, and attached
to the frame 102 in a variety of ways such that when deployed in an
expanded configuration in the blood vessel, the occlusion device
100 prevents blood flow through the vessel. In some embodiments,
the barrier 104 is coupled to the frame 102 via sutures, adhesives,
clips, or other form of attachment. The barrier 104 may be made of
any appropriate biocompatible material suitable for occluding a
vessel, such as a mesh. In some embodiments, the barrier 104 may be
made of nitinol, elgiloy, Dacron.RTM., Gore-Tex.RTM., nylon, TFE,
PTFE, ePTFE, peritoneum, subintestinal submucosa or other synthetic
or biological membrane. Further materials that can be used for both
the frame 102 and barrier 106 portions can be found, for example,
in U.S. Patent Pub. No. 2007/0292472 A1 to Paul et al., which is
hereby incorporated by reference in its entirety.
[0117] FIG. 40B illustrates a side view of the occluder illustrated
in FIG. 40A. FIG. 40C illustrates a section through line A-A of
FIG. 40B, showing the barrier 104 as well as frame 102. FIG. 40D is
an end view of the device illustrated in FIGS. 40A-40C.
[0118] While the above occlusion device 100 is described as having
a frame portion 102 and a barrier portion 104, various other
occlusion devices to prevent blood flow through the vessel lumen
are also within the scope of the invention, such as plugs, sponges,
coils, adhesives, prothrombotic agents, and the like.
[0119] In the embodiment illustrated in FIG. 40A-40D, the axial
length of the frame when in the compressed configuration is
generally within the range of from about 5 mm to about 30 mm, or
about 10 mm to about 20 mm in some embodiments. The outside
diameter of the frame when compressed within the catheter is
generally no greater than about 8 French, and preferably no greater
than about 4 French in some embodiments. The maximum outside
diameter of the occlusion device when in an unconstrained expansion
is generally within the range of from about 2 mm to about 16 mm, or
about 4 mm to about 12 mm in some embodiments.
[0120] FIGS. 41A-41D illustrates the occlusion device 100 of FIGS.
40A-40D in a deployed configuration. As noted above, the occlusion
device 100 may be made of a shape memory material to facilitate
self-expansion of the device from a reduced to an enlarged
configuration. In other embodiments, the device 100 is
balloon-expandable. As shown, the diameter of proximal end 103 of
the device 100' expands to greater than that of the distal end 105
in order to engage the vessel wall and occlude the vessel. In some
embodiments, the diameter of the proximal end 103 expands to at
least about 110%, 120%, 130%, 140%, 150%, 200%, or more of its
diameter in an undeployed configuration. In some embodiments, the
device 100 includes, such as on its proximal end 103, one or more
retention structures for retaining the device 100 in the vessel
wall. In some embodiments, a plurality of barbs or other anchors
are provided, for engaging adjacent tissue to retain the occlusion
device 100 in its implanted position and to limit relative movement
between the tissue and the occlusion device 100. The anchors are
provided on one device 100. The anchors are provided on one or more
of the struts 106, or other portion of frame 14. In some
embodiments, every strut, every second strut, or every third strut
are provided with one or two anchors each, or more. The anchor can
be in a form or a barb, spike, or other appropriate configuration
for securing the occlusion device 100 to the vessel wall, as
illustrated in greater detail in FIG. 43 below.
[0121] FIGS. 42A-42B illustrate an embodiment of the frame 102
portion of the delivery device described above in connection with
FIGS. 2A-3D in its undeployed (FIG. 42A) and deployed (FIG. 42B)
configurations with the barrier portion 104 omitted for
clarity.
[0122] FIG. 43 is a side cross-sectional view of an occlusion
device 100 in an expanded configuration and implanted within vessel
400. As previously described, the occlusion device 100 has a
proximal end 103, distal end 105, and one or more anchors 112 to
limit relative movement between the occlusion device 100 and the
vessel wall 400. The device 100 may have any number of anchors
depending on the desired clinical result, such as at least 1, 2, 3,
4, 5, 6, or more anchors.
[0123] FIG. 44 is a longitudinal cross-sectional view of an
occlusion device 100 such as that illustrated in FIG. 43, and in an
undeployed configuration within a delivery catheter 200. Delivery
catheter 200 includes an inner catheter member 204 and an outer
catheter member 202. Occlusion device resides within a lumen of
outer catheter member 202. Relative movement of inner catheter
member 204 relative to outer catheter member 202, such as
retraction of outer catheter member 202 relative to inner catheter
member 204 or pushing of inner catheter member 204 distally
relative to outer catheter member 202 can facilitate deployment of
the occlusion device 100 within the vessel 400. Inner catheter
member 204 may comprise a concentric tube, a push wire, or other
structure capable of transmitting a deployment activating
force.
[0124] Occlusion device 100 as shown is releasably attached to a
detach mechanism 120 that allows for retraction and repositioning
of the occluder member prior to deployment. The detach mechanism
120 can be any of a wide variety of mechanisms to provide
releasable detachment, for example, mechanical, chemical, or
electrolytic detachment. Some examples of mechanical detach
mechanisms include a snare, suture loop, clip and the like. The
proximal end of the catheter preferably includes a leer lock or
similar mechanism for coupling to a syringe or other injector for
inserting a vein-occluding substance into the vein.
[0125] In some embodiments, after the occlusion device is deployed,
a vein-occluding material such as a sclerosing agent is injected
into the vein. The purpose of the vein-occluding material can be to
partially or completely destroy the endothelial cells lining the
venous lumen, expose the subendothelial collagen fibers within the
vein, and ultimately form a fibrous cord. After the lining of the
vein is damaged the vein can be forced closed by the use of
compression stocking worn by the patients. Over time the damaged
vein scars upon itself creating a completely closed vein.
Endothelial damage is preferably as complete as possible, because
otherwise, thrombus will form and layer endoluminally. The presence
of a deployed occlusion device 100 advantageously prevents distal
embolization of the vein-occlusion substance distally past the
occlusion device 100. Any vein-occluding material can be used
depending on the desired clinical result.
[0126] A wide variety of vein-occluding substances can be used. In
some embodiments, the substance can include an adhesive such as
cyanoacrylate, e.g., 2-octyl cyanoacrylate, and/or a sclerosing
agent such as hypertonic saline, sodium tetradecyl sulfate,
chromated glycerol, tetracycline, talc, bleomycin, or polydocanol.
Other adhesives that can be used include a biological glue such as
a bovine serum albumin-gluteraldehyde combination (e.g., BIOGLUE,
Cryolife, Atlanta, Ga.). In some embodiments, a foam generated
from, for example, one or more of the above components can be used
to enhance ablation and closure of the vein. The viscosity and air
bubble mixture can also be controlled taking into account the
desired clinical result. Ultrasound or other imaging modalities
such as, for example, fluoroscopy, CT, or MRI can be used to
observe and control distribution of the vein-occlusion substance.
In some embodiments, foam or other micro-bubbles within the
vein-occlusion substance can also serve as ultrasonic contrast.
Further examples of agents, methods, and devices for vein closure
that can be used as well are described, for example, in U.S. Pat.
No. 4,039,665 to Foley, U.S. Pat. No. 5,676,962 to Garrido et al.,
U.S. Pat. No. 6,572,873 to Osman et al., U.S. Pat. No. 6,726,674 to
Leu, U.S. Pat. No. 7,314,466 to Lary et al., and U.S. Patent Pub.
No. 2003/0206864 A1 to Marvin, all of which are hereby incorporated
by reference in their entireties. In some embodiments, the
invention can be practiced using a cyanoacrylate based echogenic
adhesive, visible under conventional ultrasound.
[0127] FIGS. 45-47 illustrate a cross-section of occlusion device
100 (with barrier portion 104 not shown for clarity) in varying
stages of deployment caused by relative movement of inner catheter
204 relative to outer catheter 202.
[0128] Using the systems and methods described herein provides
little to no risk of injury to surrounding nerves or tissue,
because the length of the treated vessel can be clearly identified
without unnecessary overtreatment. This is in contrast to many
other procedures which require, for example, that a catheter is
placed superior to nerves which may be juxtaposed to the saphenous
vein.
[0129] The vein closure system allows for a simple treatment for
veins, such as abnormal refluxing varicose veins. The vein closure
system includes the delivery system and the unique intravascular
adhesive. The procedure is less invasive, less painful, more
effective and easier to recover from compared to existing
treatments.
[0130] Although this application has been disclosed in the context
of certain embodiments and examples, it will be understood by those
skilled in the art that the present application extends beyond the
specifically disclosed embodiments to other alternative embodiments
and/or uses of the application and obvious modifications and
equivalents thereof. Additionally, the skilled artisan will
recognize that any of the above-described methods can be carried
out using any appropriate apparatus. Further, the disclosure herein
of any particular feature in connection with an embodiment can be
used in all other disclosed embodiments set forth herein. Thus, it
is intended that the scope of the present application herein
disclosed should not be limited by the particular disclosed
embodiments described above.
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