U.S. patent application number 13/084880 was filed with the patent office on 2011-08-04 for method of restoring blood flow through an obstructed blood vessel of the brain.
This patent application is currently assigned to MINDFRAME, INC.. Invention is credited to Andrew Cragg, David A. Ferrera, John Fulkerson.
Application Number | 20110190797 13/084880 |
Document ID | / |
Family ID | 41065698 |
Filed Date | 2011-08-04 |
United States Patent
Application |
20110190797 |
Kind Code |
A1 |
Fulkerson; John ; et
al. |
August 4, 2011 |
METHOD OF RESTORING BLOOD FLOW THROUGH AN OBSTRUCTED BLOOD VESSEL
OF THE BRAIN
Abstract
An acute stroke recanalization system and processes include
catheter-based improved reconstrainable or tethered neurological
devices which are deliverable through highly constricted and
tortuous vessels, crossing the zone associated with subject
thrombi/emboli, where deployment impacts, addresses or bridges the
embolus, compacting the same into luminal walls which enables
perfusion and lysis of the embolus, while the improved neurological
medical device itself remains contiguous with the delivery system
acting as a filter, basket or stand alone stenting mechanism,
depending on the status of the embolus and other therapeutic
aspects of the treatment being offered for consideration.
Inventors: |
Fulkerson; John; (Rancho
Santa Margarita, CA) ; Ferrera; David A.; (Redondo
Beach, CA) ; Cragg; Andrew; (Edina, MN) |
Assignee: |
MINDFRAME, INC.
Irvine
CA
|
Family ID: |
41065698 |
Appl. No.: |
13/084880 |
Filed: |
April 12, 2011 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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12123390 |
May 19, 2008 |
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13084880 |
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60980736 |
Oct 17, 2007 |
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61044392 |
Apr 11, 2008 |
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61015154 |
Dec 19, 2007 |
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60989422 |
Nov 20, 2007 |
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60987384 |
Nov 12, 2007 |
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61019506 |
Jan 7, 2008 |
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Current U.S.
Class: |
606/159 |
Current CPC
Class: |
A61B 2017/22038
20130101; A61B 2017/22082 20130101; A61F 2/013 20130101; A61F
2250/0059 20130101; A61M 29/02 20130101; A61B 2017/00867 20130101;
A61B 17/221 20130101; A61B 2017/00845 20130101; A61B 17/320725
20130101; A61M 2025/1095 20130101; A61M 2025/1097 20130101; A61F
2/82 20130101; A61B 17/3207 20130101 |
Class at
Publication: |
606/159 |
International
Class: |
A61B 17/22 20060101
A61B017/22 |
Claims
1. A method of restoring blood flow through an obstructed blood
vessel of the cerebral vasculature, comprising: identifying an
obstructed blood vessel within the cerebral vasculature of a
patient, the obstructed blood vessel having an occlusive embolus;
inserting a catheter-based revascularization system within the
obstructed blood vessel; wherein the catheter-based
revascularization system comprises an outer catheter and an inner
catheter longitudinally moveable with respect to each other;
wherein the inner catheter comprises a pusher and a self-expandable
revascularization device eccentrically tethered to a distal end of
the pusher; wherein the self-expandable revascularization device
comprises a generally cylindrical body having an open proximal end,
an open distal end, and a plurality of struts that form a plurality
of cells between the proximal and distal ends; positioning the
outer catheter at a location distal to the embolus; retracting the
outer catheter to deploy the self-expandable revascularization
device at the location of the embolus thereby compressing the
embolus against a luminal wall of the blood vessel and restoring
flow through the blood vessel; wherein the restored blood flow
facilitates natural lysis of the embolus; wherein the natural lysis
and compression of the embolus cause fragmentation of at least a
portion of the embolus into a plurality of embolic fragments,
wherein one or more of said embolic fragments pass through the open
distal end of the self-expandable revascularization device
downstream of the embolus; and wherein the self-expandable
revascularization device exerts continuous radial pressure at the
location of the embolus to further facilitate blood flow through
the blood vessel as the embolus lyses; resheathing the
revascularization device within the outer catheter; and removing
the revascularization system from the patient.
2. The method of claim 1, wherein the revascularization device is
permanently tethered to a distal end of the pusher.
3. The method of claim 1, wherein the revascularization device is
detachably tethered to a distal end of the pusher.
4. The method of claim 1, wherein the revascularization device
comprises radiopaque markers configured for tracking of the
revascularization device.
5. The method of claim 4, further comprising tracking the
revascularization device to confirm proper positioning with respect
to the embolus.
6. The method of claim 1, wherein deploying the self-expandable
revascularization device at the location of the embolus comprises
creating an immediate flow channel within the blood vessel of at
least about 50% of the diameter of the blood vessel of the cerebral
vasculature.
7. The method of claim 1, wherein the pusher comprises a
variable-pitch hypotube.
8. The method of claim 1, wherein the pusher comprises a wire.
9. The method of claim 1, wherein at least a portion of said inner
catheter comprises a flexible material configured to permit flexion
and extension to navigate through curved vessels of the cerebral
vasculature.
10. The method of claim 1, further comprising infusing lytic agents
to the location of the embolus through the revascularization
system.
11. The method of claim 1, further comprising removing at least a
portion of the embolus captured by the revascularization
device.
12. The method of claim 1, wherein the revascularization device
comprises a self-expanding microstent.
13. The method of claim 1, further comprising morselizing at least
a portion of the embolus by mechanical manipulation of the
revascularization device.
14. The method of claim 1, wherein inserting the catheter-based
revascularization system within the obstructed blood vessel
comprises advancing the revascularization system over a guidewire
proximate a location of the embolus.
15. A method of restoring blood flow through an obstructed blood
vessel of the brain to treat acute ischemic stroke, comprising:
identifying an obstructed blood vessel within the cerebral
vasculature of a patient, the obstructed blood vessel having an
embolus; inserting a catheter-based revascularization system within
the obstructed blood vessel; wherein the catheter-based
revascularization system comprises an outer catheter and an inner
catheter longitudinally moveable with respect to each other;
wherein the inner catheter comprises a pusher and a self-expandable
revascularization device tethered to a distal end of the pusher;
wherein the self-expandable revascularization device comprises an
open proximal end, an open distal end, and a plurality of struts
that form a plurality of cells between the proximal and distal
ends; positioning the outer catheter at a location distal to the
embolus; retracting the outer catheter, thereby deploying the
self-expandable revascularization device at the location of the
embolus, thereby compressing the embolus or lesion against a
luminal wall of the obstructed blood vessel and restoring flow
through the obstructed blood vessel; wherein the restored blood
flow facilitates natural lysis of the embolus; wherein the natural
lysis and compression of the embolus cause fragmentation of at
least a portion of the embolus into a plurality of fragments,
wherein one or more of said fragments pass through the open distal
end of the self-expandable revascularization device downstream of
the embolus; and wherein the self-expandable revascularization
device exerts continuous radial pressure at the location of embolus
to further facilitate blood flow through the blood vessel as the
embolus lyses; resheathing the revascularization device within the
outer catheter; and removing the revascularization system from the
patient.
16. The method of claim 15, wherein the self-expandable
revascularization device is generally cylindrical and eccentrically
tethered to the distal end of the pusher via a plurality of
tethered lines.
17. The method of claim 15, further comprising morselizing at least
a portion of the embolus by mechanical manipulation of the
revascularization device.
18. The method of claim 15, further comprising removing at least a
portion of the embolus captured by the revascularization
device.
19. The method of claim 15, wherein deploying the self-expandable
revascularization device at the location of the embolus comprises
creating an immediate flow channel within the blood vessel of at
least about 50% of the diameter of the blood vessel of the cerebral
vasculature.
20. The method of claim 15, wherein inserting a catheter-based
revascularization system within the obstructed blood vessel
comprises advancing the revascularization system over a guidewire
proximate a location of the embolus.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation of U.S. application Ser.
No. 12/123,390, filed May 19, 2008, which claims priority to, and
incorporates expressly by reference U.S. Provisional Application
Ser. No. 60/980,736, filed Oct. 17, 2007; U.S. Provisional
Application Ser. No. 61/044,392, filed Apr. 11, 2008; U.S.
Provisional Application Ser. No. 61/015,154, filed Dec. 19, 2007;
U.S. Provisional Application Ser. No. 60/989,422, filed Nov. 20,
2007; U.S. Provisional Application Ser. No. 60/987,384, filed Nov.
12, 2007; and U.S. Provisional Application Ser. No. 61/019,506,
filed Jan. 7, 2008; each as if fully set forth herein.
BACKGROUND OF THE INVENTION
[0002] The present disclosure relates to minimally invasive and
catheter delivered revascularization systems for use in the
vasculature, especially those suited for usage above the juncture
of the Subclavian Artery and Common Carotid Artery. In particular,
this disclosure relates to revascularization devices for use in
treatment of ischemic stroke, including improved neurological
medical devices which are tethered or reconstrainable
self-expanding neurological medical devices.
SUMMARY OF THE INVENTION
[0003] According to embodiments of the present invention, there are
disclosed acute stroke revascularization/recanalization systems
comprising, in combination; catheter systems having guidewires to
access and emplace improved neurological medical devices into the
cerebral vasculature, the systems including proximal stainless
steel pushers with distal nitinol devices or one-piece nitinol
devices. In some embodiments, the systems comprise a polymeric
liner incorporated within the pusher to improve trackability of the
guidewire. In some embodiments, the polymeric liner extends beyond
the distal tip of the pusher for guiding the guidewire and
preventing entanglement in the nitinol device.
[0004] According to embodiments, there are disclosed one-piece
nitinol devices in combination with the above disclosed and/or
claimed catheter systems.
[0005] Briefly stated, according to embodiments a novel enhanced
tethered revascularization device is deliverable through highly
constricted and tortuous vessels, entering a zone associated with
subject thrombi/emboli, where deployment impacts the embolus,
compacting the same into luminal walls which enables perfusion and
lysis of the embolus, while the revascularization device itself
remains continuous with the delivery system acting as a filter,
basket or stand alone revascularization mechanism, depending on the
status of the embolus and other therapeutic aspects of the
treatment being offered for consideration.
[0006] According to embodiments of the system and processes of the
present invention, in certain iterations, once deployed the instant
system compacts the embolus against the luminal wall, creating a
channel for blood flow which may act like a natural lytic agent to
lyse or dissolve the embolus.
[0007] According to embodiments, there is provided an improved
neurological medical device which comprises, in combination, a
catheter system effective for delivering a combination radial
filter/revascularization device and basket assembly into a desired
location in the cerebral vascular system, a self-expanding radial
filter/revascularization device and basket assembly detachably
tethered to the catheter system which functions in at least three
respective modes, wherein the radial filter/revascularization
device and basket assembly is attached to the catheter and wherein
radial filter/revascularization device and basket assembly further
comprises at least two states per mode, a retracted state and an
expanded state; and wherein the radial filter/revascularization
device and basket assembly may retracted into the retracted state
after deployment in an expanded state, in each mode.
[0008] According to embodiments, there is provided a process
comprising in combination providing a revascularization device
tethered to a catheter by emplacing the system into a patient for
travel to a desired location in a vessel having an
obstruction/lesion and deploying the revascularization device by
allowing it to move from a first state to a second state across a
lesion which compresses the subject embolus into a luminal wall to
which it is adjacent whereby creating a channel for blood flow as a
lytic agent, and removing the system which the obstruction/lesion
is addressed.
[0009] It is noted that if blood flow does not lyse the blood
embolus, lytic agents can be administered via the guidewire lumen,
as a feature of the present invention.
[0010] According to embodiments, there is provided a process
whereby the revascularization device tethered to a catheter
functions as a radial filter to prevent downstream migration of
emboli.
[0011] The U.S. Food and Drug Administration (FDA) has previously
approved a clot retrieval device (The Merci.RTM. brand of retriever
X4, X5, X6, L4, L5 & L6: Concentric Medical, Mountain View,
Calif.). Unfortunately, when used alone, this clot retriever is
successful in restoring blood flow in only approximately 50% of the
cases, and multiple passes with this device are often required to
achieve successful recanalization. IA thrombolytics administered
concomitantly enhance the procedural success of this device but may
increase the risk of hemorrhagic transformation of the
revascularization infarction. There have been several reports of
coronary and neuro-stent implantation used for mechanical
thrombolysis of recalcitrant occlusions. In summary, stent
placement with balloon-mounted or self-expanding coronary and
neuro-types of stents has been shown to be an independent predictor
for recanalization of both intracranial and extra cranial
cerebro-vasculature occlusions. This provides some insight into
approaches needed to overcome these longstanding issues.
[0012] By way of example, self-expanding stents designed
specifically for the cerebro-vasculature can be delivered to target
areas of intracranial stenosis with a success rate of >95% and
an increased safety profile of deliverability because these stents
are deployed at significantly lower pressures than balloon-mounted
coronary stents. However, systems using this data have yet to
become commercial, available or accepted by most practitioners.
[0013] The use of self-expanding stents is feasible in the setting
of symptomatic medium--and large-vessel intracranial occlusions.
With stent placement as a first-line mechanical treatment or as a
"last-resort" maneuver, TIMI/TICI 2 or 3 revascularization can be
successfully obtained, according to clinical data now
available.
[0014] The literature likewise suggests that focal occlusions
limited to a single medium or large vessel, particularly solitary
occlusions of the MCA or VBA, may be preferentially amenable to
stent placement and thus can help clinicians to achieve improved
rates of recanalization. In addition, gender may play a role in the
success of self-expanding stent implementation. However, systems
need to be designed to execute on this.
[0015] Despite increasing utilization of prourokinase rt-PA
(recombinant tissue plasminogen activator) or other antithrombotic
agents (e.g., Alteplase.RTM. and Reteplase.RTM.), recanalization
rates remain approximately 60%. The major concerns with
pharmacologic thrombolysis (alone) has been the rate of hemorrhage,
inability to effectively dissolve fibrin\platelet-rich clots,
lengthy times to recanalization, and inability to prevent abrupt
reocclusions at the initial site of obstruction. In PROACTII, ICH
with neurologic deterioration within 24 hours occurred in 10.9% of
the prourokinase group and 3.1% of the control group (P=0.06),
without differences in mortality. Abrupt reocclusions or
recanalized arteries has been found to occur relatively frequently,
even with the addition of angioplasty or snare manipulation for
mechanical disruption of thrombus, and seems to be associated with
poor clinical outcomes.
[0016] The use of other mechanical means has been reported to be
effective in recanalization of acute occlusions. It makes sense
that a combination of mechanical and pharmacologic approaches would
yield greater benefit.
[0017] A known investigation in an animal model has shown, both the
Wingspan.RTM. brand of self-expanding stent and Liberte.RTM. brand
of balloon-mounted stent (Boston Scientific, Boston, Mass.) were
able to re-establish flow through acutely occluded vessels. The
self-expanding stents performed better than the balloon-mounted
stents in terms of navigability to the target site. The
self-expanding stents incurred lower rates of vasospasm and
side-branch occlusions, which suggests superiority of these stents,
over balloon-mounted stents, to maintain branch vessel patency
during treatment of acute vessel occlusion. In a previous animal
studies conducted, intimal proliferation and loss of lumen diameter
were seen after the implantation of bare-metal, balloon-expandable
stents. The literature further supports this set of issues.
[0018] These phenomena are believed to be attributable to intimal
injury created during the high-pressure balloon angioplasty that is
required for stent deployment.
[0019] Compared with coronary balloon-mounted stents,
self-expanding stents designed for use in the intracranial
circulation are superior because they are easier to track to the
intracranial circulation and safer to deploy in vessels in which
the true diameter and degree of intracranial atherosclerotic
disease are unclear.
[0020] Moreover, based on previous experience, currently available
self-expanding stents provide enough radial outward force at body
temperature to revascularize occluded vessels, with low potential
for the negative remodeling and in-stent restenosis that are
associated with balloon-mounted stents in nonintracranial vascular
beds.
[0021] Because self-expanding stents are not mounted on balloons,
they are the most trackable of the stents currently available for
the intracranial circulation. Unlike clot retrievers, which lose
access to the target (occlusion site) every time they are retrieved
(and often to necessitate multiple passes), self-expanding stents
allow for wire access to the occlusion at all times, increasing the
safety profile of the procedure by not requiring repeat maneuvers
to gain access to the target site (as in the case for the
Merci.RTM. brand of clot retriever).
[0022] Self-expanding stent placement of acute intracranial vessel
occlusions may provide a novel means of recanalization after
failure of clot retrieval, angioplasty, and/or thrombolytic
therapy. The patency rates in this series are encouraging, yet
issues remain to be addressed.
[0023] In the setting of acute stroke, restoring flow is of
singular importance. In-stent stenosis or delayed stenosis may be
treated in a delayed fashion on an elective basis, should the
patient achieve a functional recovery from the stroke.
[0024] Recanalization with self-expanding stents may provide flow
through the patent artery, and restore flow to the perforators, or,
alternatively, they may remain occluded. Restoring flow to the main
artery, however, will reduce the stroke burden. What is needed is a
solution leveraging positive aspects of stent-based treatment
without the negative outcomes which have been associated with
traditional stenting.
DRAWINGS OF THE INVENTION
[0025] The above-mentioned features and objects of the present
disclosure will become more apparent with reference to the
following description taken in conjunction with the accompanying
drawings wherein like reference numerals denote like elements and
in which:
[0026] FIG. 1 is a perspective view of an embodiment of an acute
stroke recanalization system according to embodiments of the
present disclosure in a first configuration; and
[0027] FIG. 2 is a perspective view of an embodiment of an acute
stroke recanalization system according to embodiments of the
present disclosure tailored for use with the neurovasculature in a
second configuration, further illustrating modular aspects of the
system as used with tethered or reconstrainable self-expanding
neurological medical devices.
[0028] FIG. 2A illustrates a detailed view of the inner catheter of
FIG. 2.
[0029] FIGS. 3A-3D illustrate an embodiment of an inner catheter of
the acute stroke recanalization system of FIGS. 1 and 2.
[0030] FIGS. 4A-4C illustrate a perspective view, a side view, and
a front view, respectively, of an embodiment of a self-expanding
revascularization device.
[0031] FIG. 5 illustrates an embodiment of a stroke device.
[0032] FIG. 6 shows a schematic of a delivery system and exemplary
iteration of a temporary tethered stent mechanism according to the
present disclosure.
[0033] FIG. 7 likewise schematically depicts a delivery system with
embodiments of a tethered stent for use with an over-the wire
guidewire system.
[0034] FIGS. 8A-8D illustrate an embodiment of a revascularization
device configured for eccentric coupling to a pusher.
DETAILED DESCRIPTION OF THE INVENTION
[0035] The present inventors have realized that by leveraging a
conventional self-expanding revascularization device delivery
platform, a poly-modic system can be iterated which impacts,
addresses and/or crosses an embolus, radially filters, and either
removes the offending embolus or is optionally emplaced to address
the same. A paucity of extant systems effective for such
combination therapies is noted among the art.
[0036] Using endovascular techniques self-expandable tethered or
reconstrainable self-expanding neurological medical devices offer
instant revascularization/recanalization of MCAs and related
vessels, without any of the traditional concerns associated with
stenting, according to embodiments of the present invention.
[0037] Expressly incorporated herein by reference are the following
U.S. Letters patents and publications, each as if fully set forth
herein: 2005/0119684; 2007/0198028; 2007/0208367; U.S. Pat. Nos.
5,449,372; 5,485,450; 5,792,157; 5,928,260; 5,972,019; 6,485,500;
7,147,655; 7,160,317; 7,172,575; 7,175,607; and 7,201,770.
[0038] The instant system allows for natural lysis,
revascularization of the challenged vessels, and importantly
radially filters any particulates generated, to obviate the need to
be concerned with distal migration of the same, unlike prior
systems or applications which include largely "off-label" usages of
devices approved only for aneurysms in the brain.
[0039] The present disclosure relates to revascularization devices
used to treat, among other things, ischemic stroke. Naturally,
therefore, the revascularization devices of the present disclosure
are designed to be used in neuro-type applications, wherein the
specifications of the present catheters and revascularization
devices may be deployed in the blood vessels of the cerebral
vascular system. Similarly contemplated for the revascularization
systems and catheters of the present disclosure is deployment in
other parts of the body wherein the specifications of the present
disclosure may be used in other vessels of the body in a
non-invasive manner.
[0040] According to embodiments, disclosed herein is a
catheter-based revascularization system. The revascularization
devices of the present disclosure are for revascularization of
blood vessels. When the catheter-based revascularization system of
the present disclosure is deployed into a blood vessel having an
embolus, the revascularization device is expanded thereby opening
the vessel so that the vessel can resume proper blood flow.
[0041] According to the instant teachings, deployment of the system
of the present disclosure, establishes immediate 50% of the
diameter of the lumen patency of the vessel being addressed. Among
the prior art, no system having adequately small profile with
flexibility to promote improved access for in-site treatment is
known which may be used as a temporary (not implanted) solution.
Those skilled in the art readily understand that detachment methods
comprising mechanical, electrical, hydraulic, chemical, or thermal,
and others are within the scope of the instant teachings.
[0042] Moreover, as the embolus dissolves, either via blood flow or
by infusing lytic agents than the guidewire lumen, the deployed
revascularization device radially filters larger embolus particles
from traveling downstream, thereby reducing the chances of further
complications. Once the blood vessel is revascularized, the
revascularization device is modified to be in a removable state
together with filtered detritus, and the catheter-revascularization
system is removed from the blood vessels of the patient.
[0043] Likewise, in the event that no resolution of the embolus is
noted in the instant revascularization system the inventors
contemplate detachment and employment as a stent of the cage-like
membrane. Angiographic recanalization has been associated with
improvement in clinical outcome in the setting of acute stroke
resulting from acute intracranial thrombotic occlusion. Anatomic
limitations (tortuous anatomy, length of the occlusion, or location
of occlusion) or supply limitations are among the reasons
precluding use of prior art systems until the advent of the instant
teachings.
[0044] Stenting has been used successfully to restore flow after
abrupt reocclusion occurring after recanalization with other
modalities in previous cases. Stenting has also been reported in
cases in which other modalities have failed to recanalize vessels.
Even if an underlying stenosis is rarely the cause of stroke,
stenting may play a role by morselizing the embolic clot or
trapping it against the arterial wall. In several embodiments, the
present invention comprises an acute stroke revascularization
process that comprises providing a reconstrainable self-expanding
microstent system, deploying a self-expanding microstent within a
neurological vessel; achieving at least one of revascularization
and recanalization of a subject vessel; and removing the
self-expanding microstent. In some embodiments, at least one
supplemental therapy is also provided, and comprises one or more of
the following: pharmacological thrombolytic agents, intraarterial
thrombolytics, and mechanical manipulation.
[0045] The use of intracranial stents as a method for arterial
recanalization during cerebral ischemia caused by focal occlusion
of an intracranial vessel has been demonstrated to have benefits in
some cases. Despite the use of available pharmacological and
mechanical therapies, angiographic recanalization of occluded
vessels has not been adequately achieved before stent placement, in
most cases.
[0046] When SAH and intracranial hematoma occurred in patients in
whom balloon-mounted stents were used, they most likely resulted
from distal wire perforation. The distal wire purchase needed to
navigate a coronary stent into the intracranial circulation may
explain the occurrence of these adverse events. Alternatively,
multiple manipulations of the Merci.RTM. brand of retriever device
or expansion of balloon-mounted stents may have induced
microdissections in the vessel. Stents designed for intracranial
navigation have better navigability and pliability. The
Wingspan.RTM. brand of stent (Boston Scientific) was designed to
have more radial force than the Neuroform.RTM. brand of stent and
may further improve this technique. However, the act clearly needs
to advance further in this area.
[0047] IA therapy for stroke has evolved during the past decade.
Approval of the Merci.RTM. brand of retriever device represents a
significant step toward achieving better outcomes in acute stroke
for patients not suitable for IV tPA. However, recanalization is
not always achieved using this device. Therefore, additional
treatment options are required, as offered for consideration
herein.
[0048] Spontaneous dissection of the internal carotid artery (ICA)
is one of the main causes of ischemic stroke in young and
middle-aged patients, representing 10% to 25% of such cases.
Because infarct due to dissection is mainly thromboembolic,
anticoagulation has been recommended to prevent new stroke in
patients with acute dissection, provided they have no
contraindications. In the acute phase, intravenous recombinant
tissue-type plasminogen activator (IV rtPA) given within 3 hours
after onset of stroke due to dissection is reportedly safe and
effective. However, this often needs supplemental therapy to be
effective.
[0049] Endovascular treatment with stent deployment for ICA
dissection with high-grade stenosis or occlusion may be most
appropriate when anticoagulation fails to prevent a new ischemic
event. In such cases, the MCA may be patent. However, to compare
outcomes of patients with acute stroke consecutive to MCA occlusion
due to ICA dissection treated either by stent-assisted endovascular
thrombolysis/thrombectomy or by IV rtPA thrombolysis. Stent
assisted endovascular thrombolysis/thrombectomy compared favorably
with IV rtPA thrombolysis, underscoring the need for the instant
device.
[0050] The main limitation of this procedure is the immediate need
for an experienced endovascular therapist. The number of cases of
MCA occlusion due to carotid artery dissection was quite small and
represented <10% of patients admitted for carotid dissection.
However, despite these promising preliminary results, potential
drawbacks related to the procedure must be considered. Acute
complications such as transient ischemic attack, ischemic stroke,
femoral or carotid dissection, and death have been reported. Other
potential hazards of endovascular treatment of carotid dissection
could have been observed. On balance, the risk-benefit favors
solutions like the present invention.
[0051] Most patients with acute cerebrovascular syndrome with MC
occlusion consecutive to ICA dissection have poor outcomes when
treated with conventional IV rtPA thrombolysis, whereas most
patients treated with stent-assisted endovascular
thrombolysis/thrombectomy show dramatic improvements. Further large
randomized studies are required to confirm these data, which trends
likewise are technical bases for the instant systems.
[0052] According to embodiments and as illustrated in FIG. 1,
catheter-based revascularization system 100 provides a platform for
lysing emboli in occluded blood vessels. Accordingly,
catheter-based revascularization system 100 generally comprises
control end 102 and deployment end 104. According to embodiments,
control end 102 is a portion of the device that allows a user, such
as a surgeon, to control deployment of the device through the blood
vessels of a patient. Included as part of control end 102 is
delivery handle 106 and winged apparatus 108, in some embodiments.
Those skilled in the art readily understand module 113 (see FIG. 2)
is detachable.
[0053] According to some examples of the instant system during
shipping of catheter-revascularization system 100, shipping lock
(not shown) is installed between delivery handle 106 and winged
apparatus 108 to prevent deployment and premature extension of
revascularization device 124 (see FIG. 2) while not in use.
Furthermore, by preventing delivery handle 106 from being advanced
towards winged apparatus 108, coatings applied to revascularization
device 124 are stored in a configuration whereby they will not rub
off or be otherwise damaged while catheter-based revascularization
system 100 is not in use.
[0054] According to embodiments, agent delivery device 130 provides
a conduit in fluid communication with the lumen of the
catheter-based revascularization system 100 enabling users of the
system to deliver agents through catheter-revascularization system
100 directly to the location of the embolus. The instant
revascularization system delivery device may be made from materials
known to artisans, including stainless steel hypotube, stainless
steel coil, polymer jackets, and/or radiopaque jackets. In one
embodiment, the revascularization systems comprise a plurality of
apertures 118 allowing infusable lytic agents to exit radially and
distally into at least a subject embolus when transmitted through
agent delivery device which is in fluid communication therewith.
The revascularization systems according to several embodiments
herein can comprise radiopacity for imaging purposes.
[0055] Accordingly, luer connector 132 or a functional equivalent
provides sterile access to the lumen of catheter-based
revascularization system 100 to effect delivery of a chosen agent.
Artisans will understand that revascularization devices of the
present invention include embodiments made essentially of nitinol
or spring tempered stainless steel. Revascularization devices
likewise may be coated or covered with therapeutic substances in
pharmacologically effective amounts or lubricious materials.
According to embodiments, coatings include namodopene,
vasodialators, sirolamus, and paclitaxel. Additionally, at least
heparin and other coating materials of pharmaceutical nature may be
used.
[0056] Deployment end 104 of catheter-based revascularization
system 100 comprises proximal segment 110 and distal segment 120.
Proximal segment 110, according to embodiments, houses distal
segment 120 and comprises outer catheter 112 that is of a suitable
length and diameter for deployment into the blood vessel of the
neck, head, and cerebral vasculature. For example in some
embodiments, proximal segment 110 is from at least about 100 cm to
approximately 115 cm long with an outer diameter of at least about
2.5 French to about 4 French.
[0057] Referring also to FIG. 2, distal segment 120 comprises inner
catheter 122 and revascularization device 124 (as shown here in one
embodiment having uniform cells, variable cells likewise being
within other embodiments of the present invention), which is
connected to inner catheter 122. Inner catheter 122, according to
embodiments, is made from stainless steel coil, stainless steel
wire, or ribbon or laser cut hypotube and is of a suitable length
and diameter to move through outer catheter 112 during deployment.
For example, inner catheter 122 extends from outer catheter 112 38
cm, thereby giving it a total length of between at least about 143
and 175 cm. The diameter of inner catheter 122 according to the
exemplary embodiment is 2.7 French, with an inner diameter of at
least about 0.012 to 0.029 inches. The inner diameter of inner
catheter 122 may be any suitable diameter provided inner catheter
122 maintains the strength and flexibility to both deploy and
retract revascularization device 124. In one embodiment, an inner
catheter 122' comprises a variable-pitch hypotube, as shown in
FIGS. 3A-D. In one embodiment, the inner catheter 122' comprises a
laser-cut, variable-pitch hypotube. Region L comprises a laser cut
transition region of the variable-pitch hypotube. Regions P1, P2
and P3 comprise three regions of the variable-pitch hypotube having
variable pitch. In one embodiment, the pitch decreases from region
P1 to region P2 and from region P2 to region P3.
[0058] Referring to both figures, revascularization device 124 is a
self-expanding, reconstrictable retractable device tethered to
inner catheter 122. Revascularization device 124 may be made from
nitinol, spring tempered stainless steel, or equivalents as known
and understood by artisans, according to embodiments.
Revascularization device 124, according to embodiments and
depending on the particular problem being addressed, may be from at
least about 3.5 mm to about 50 mm in its expanded state. In an
expanded state, revascularization device 124 is designed to expand
in diameter to the luminal wall of blood vessel where it is
deployed.
[0059] As known to artisans, revascularization device 124 may be
coated or covered with substances imparting lubricous
characteristics or therapeutic substances, as desired. Naturally,
the expandable mesh design of revascularization device 124 must be
a pattern whereby when revascularization device 124 is retracted,
it is able to fully retract into inner catheter 122. The nature of
the cell type likewise changes with respect to the embodiment used,
and is often determined based upon nature of the clot.
[0060] In one embodiment, a revascularization device 124' comprises
a plurality of struts 127 and a plurality of open cells 129, as
shown in FIGS. 4A-4C. In accordance with some embodiments,
recapturability, flexibility and tracking are enabled by the struts
of the revascularization device 124', which permit flexion and
extension to navigate through curved vessels. FIG. 5 illustrates a
stroke device having a revascularization device 124'' coupled to a
distal end of an inner catheter 122''. In one embodiment, a
revascularization device 124'' comprises one or more markers 125.
The markers 125 can comprise at least one marker material selected
from the group consisting essentially of platinum and gold. With
reference to FIG. 4B, one or more markers can be pressed into
pre-laser cut apertures 126 designed to matingly embrace the
same.
[0061] Catheter-revascularization system 100 is deployed through a
patient's blood vessels. Once the user of
catheter-revascularization system 100 determines that the embolus
to be addressed is crossed, as known and understood well by
artisans, revascularization device 124 is deployed by first
positioning outer catheter 112 in a location immediately distal to
the embolus.
[0062] Then, to revascularize/reperfuse the occluded blood vessel,
distal catheter 120 is deployed in a location whereby
revascularization device 124 expands at the location of the
embolus, as illustrated by FIG. 2. The embolus is thereby
compressed against the luminal wall of the blood vessel and blood
flow is restored. Modular detachable segment 113 is known also, and
may be swapped out, as needed, if an Rx system is used.
[0063] As discussed above and claimed below, creating a channel for
flow ideally includes making a vessel at least about
halfway-patent, or 50% of diameter of a vessel being open.
According to other embodiments, the channel created may be a
cerebral equivalent of thrombolysis in myocardial infarction TIMI
1, TIMI 2, or TIMI 3.
[0064] Restoration of blood flow may act as a natural lytic agent
and many emboli may begin to dissolve. Revascularization device 124
is designed, according to embodiments, to radially filter larger
pieces of the dissolving embolus and prevent them from traveling
distal to the device and potentially causing occlusion in another
location. Because the revascularization device provides continuous
radial pressure at the location of the obstruction, as the embolus
dissolves, the blood flow continues to increase.
[0065] After the embolus is lysed, revascularization device 124 is
sheathed into outer catheter 112 and removed from the body.
According to embodiments, larger pieces of the thrombus may be
retracted with revascularization device 124 after being captured in
the radial filtering process. According to embodiments,
revascularization device 124 may be detachable whereby the
revascularization device 124 may detach from catheter-based
revascularization system 100 if it is determined that
revascularization device 124 should remain in the patient. As
discussed above, illustrated in the Figures, and claimed below
according to embodiments, catheter-based revascularization system
100 reconstrainable attachment or attachment by tether may be
optionally detachable. Revascularization device detachment methods
comprise mechanical, electrical hydraulic, chemical, thermal, and
those other uses known to artisans.
[0066] According now to FIG. 6, delivery tube 200 deploys tethered
cage-like device/temporary stent 201 prior to embolization, using
standard over-the-wire (OTW) system 199.
[0067] According to the disclosure, a temporary tethered cage-like
structure/tethered stent 201 is non-detachable in some embodiments
but attached either to a hypotube or guide wire 199 allowing it to
be navigated into tortuous vasculature in the brain. Device 201 may
be attached to guide wire 199 or tube 200.
[0068] FIG. 7 likewise provides further details of the instant
system, with tethered cage-like structure/temporary stent 201 being
released from delivery tube 200 using known OTW techniques.
[0069] The delivery tube 200 is a variable stiffness tube that is
able to track to and through the tortuous anatomy or the cerebral
vasculature (i.e., internal carotid artery, MCA, ACA, vertebral and
basilar).
[0070] The delivery tube 200 can be one or two pieces but must have
greater proximal pushability (stiffness) & greater distal
flexibility (softness) to allow tracking to distal cerebral
arteries.
[0071] The delivery tube 200 should also have a lumen that enables
tracking over a guide-wire. This feature provides a few benefits;
ability to track and be delivered; ability to maintain access in
the event different size devices need to be exchanged; provide
support to arterial tree during device deployment and recovery. A
flexible device may tend to herniate or prolapse into openings. The
guide wire provides a pathway (concentric) to the artery and
supports the device preventing such technical complications.
[0072] The delivery tube 200 can be mechanically attached to the
tethered stent by soldering, welding or press fitting. Likewise,
those skilled in the art readily understand their attachment
mechanisms.
[0073] The cage-like structure/stent is made of nitinol to allow it
to be compressed and loaded into an introducer for packaging.
Similarly memory-based materials likewise function, in accordance
with the instant systems.
[0074] By attaching it to a delivery wire, the cage-like
structure/stent can be placed, retracted, repositioned and
recaptured into a microcatheter.
[0075] FIGS. 8A-8D illustrate an embodiment of a revascularization
device 800 configured for eccentric coupling to a pusher. The
revascularization device 800 can be tethered to a pusher (e.g.,
wire or tube) by a plurality of tether lines 802 (also shown, for
example, in FIGS. 2 and 2A). In some embodiments, the
revascularization device 800 is eccentrically coupled to the pusher
(e.g., tethered off-center). In various embodiments, the
revascularization device comprises an open proximal end and/or an
open distal end and a generally cylindrical body (see, for example,
FIGS. 2 and 2A, 4A-4C, and 5-7).
[0076] While the apparatus and method have been described in terms
of what are presently considered to be the most practical and
preferred embodiments, it is to be understood that the disclosure
need not be limited to the disclosed embodiments. It is intended to
cover various modifications and similar arrangements included
within the spirit and scope of the claims, the scope of which
should be accorded the broadest interpretation so as to encompass
all such modifications and similar structures. The present
disclosure includes any and all embodiments of the following
claims.
[0077] It should also be understood that a variety of changes may
be made without departing from the essence of the invention. Such
changes are also implicitly included in the description. They still
fall within the scope of this invention. It should be understood
that this disclosure is intended to yield a patent covering
numerous aspects of the invention both independently and as an
overall system and in both method and apparatus modes.
[0078] Further, each of the various elements of the invention and
claims may also be achieved in a variety of manners. This
disclosure should be understood to encompass each such variation,
be it a variation of an embodiment of any apparatus embodiment, a
method or process embodiment, or even merely a variation of any
element of these.
[0079] Particularly, it should be understood that as the disclosure
relates to elements of the invention, the words for each element
may be expressed by equivalent apparatus terms or method
terms--even if only the function or result is the same.
[0080] Such equivalent, broader, or even more generic terms should
be considered to be encompassed in the description of each element
or action. Such terms can be substituted where desired to make
explicit the implicitly broad coverage to which this invention is
entitled.
[0081] It should be understood that all actions may be expressed as
a means for taking that action or as an element which causes that
action.
[0082] Similarly, each physical element disclosed should be
understood to encompass a disclosure of the action which that
physical element facilitates.
[0083] Any patents, publications, or other references mentioned in
this application for patent are hereby incorporated by reference.
In addition, as to each term used it should be understood that
unless its utilization in this application is inconsistent with
such interpretation, common dictionary definitions should be
understood as incorporated for each term and all definitions,
alternative terms, and synonyms such as contained in at least one
of a standard technical dictionary recognized by artisans and the
Random House Webster's Unabridged Dictionary, latest edition are
hereby incorporated by reference.
[0084] Finally, all referenced listed in the Information Disclosure
Statement or other information statement filed with the application
are hereby appended and hereby incorporated by reference; however,
as to each of the above, to the extent that such information or
statements incorporated by reference might be considered
inconsistent with the patenting of this/these invention(s), such
statements are expressly not to be considered as made by the
applicant(s).
[0085] In this regard it should be understood that for practical
reasons and so as to avoid adding potentially hundreds of claims,
the applicant has presented claims with initial dependencies
only.
[0086] Support should be understood to exist to the degree required
under new matter laws--including but not limited to United States
Patent Law 35 USC 132 or other such laws--to permit the addition of
any of the various dependencies or other elements presented under
one independent claim or concept as dependencies or elements under
any other independent claim or concept.
[0087] To the extent that insubstantial substitutes are made, to
the extent that the applicant did not in fact draft any claim so as
to literally encompass any particular embodiment, and to the extent
otherwise applicable, the applicant should not be understood to
have in any way intended to or actually relinquished such coverage
as the applicant simply may not have been able to anticipate all
eventualities; one skilled in the art, should not be reasonably
expected to have drafted a claim that would have literally
encompassed such alternative embodiments.
[0088] Further, the use of the transitional phrase "comprising" is
used to maintain the "open-end" claims herein, according to
traditional claim interpretation. Thus, unless the context requires
otherwise, it should be understood that the term "comprise" or
variations such as "comprises" or "comprising", are intended to
imply the inclusion of a stated element or step or group of
elements or steps but not the exclusion of any other element or
step or group of elements or steps.
[0089] Such terms should be interpreted in their most expansive
forms so as to afford the applicant the broadest coverage legally
permissible.
* * * * *