U.S. patent application number 12/720039 was filed with the patent office on 2010-09-30 for two-piece transseptal cannula, delivery system, and method of delivery.
This patent application is currently assigned to CIRCULITE, INC.. Invention is credited to Andrew J. Dusbabek, Robert C. Farnan, Robert G. Hudgins, Elizabeth Jung, Scott A. Olson.
Application Number | 20100249491 12/720039 |
Document ID | / |
Family ID | 42306711 |
Filed Date | 2010-09-30 |
United States Patent
Application |
20100249491 |
Kind Code |
A1 |
Farnan; Robert C. ; et
al. |
September 30, 2010 |
TWO-PIECE TRANSSEPTAL CANNULA, DELIVERY SYSTEM, AND METHOD OF
DELIVERY
Abstract
A cannula assembly for directing blood from the heart of a
patient and a minimally invasive method of implanting the same. The
cannula assembly includes a flexible cannula body having a proximal
end and a distal end with a receiving portion, and a transseptal
tip having a distal end and a proximal end with an engaging
portion. First and second anchors are coupled to the transseptal
tip and configured to be deployed from a contracted state to an
expanded state. The engaging portion of the transseptal tip is
operable to removably engage the receiving portion of the flexible
cannula body in vivo.
Inventors: |
Farnan; Robert C.; (River
Vale, NJ) ; Olson; Scott A.; (Princeton, MN) ;
Jung; Elizabeth; (Zimmerman, MN) ; Dusbabek; Andrew
J.; (Dayton, MN) ; Hudgins; Robert G.;
(Monticello, MN) |
Correspondence
Address: |
WOOD, HERRON & EVANS, LLP
2700 CAREW TOWER, 441 VINE STREET
CINCINNATI
OH
45202
US
|
Assignee: |
CIRCULITE, INC.
Saddle Brook
NJ
|
Family ID: |
42306711 |
Appl. No.: |
12/720039 |
Filed: |
March 9, 2010 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61163931 |
Mar 27, 2009 |
|
|
|
Current U.S.
Class: |
600/16 ; 600/424;
604/164.1; 604/175; 604/96.01 |
Current CPC
Class: |
A61M 1/3653 20130101;
A61M 60/857 20210101; A61M 29/00 20130101; A61M 60/122 20210101;
A61M 1/3659 20140204; A61M 2025/0233 20130101; A61M 25/005
20130101; A61M 25/04 20130101; A61B 17/3478 20130101; A61M 25/0068
20130101; A61M 60/148 20210101; A61M 2205/0266 20130101 |
Class at
Publication: |
600/16 ; 604/175;
604/96.01; 604/164.1; 600/424 |
International
Class: |
A61M 1/12 20060101
A61M001/12; A61M 5/00 20060101 A61M005/00; A61M 29/02 20060101
A61M029/02; A61B 17/34 20060101 A61B017/34; A61B 5/05 20060101
A61B005/05 |
Claims
1. A cannula assembly, comprising: a flexible cannula body having
distal and proximal ends with a lumen extending therebetween, the
distal end including a receiving portion; a transseptal tip having
distal and proximal ends, the proximal end including an engaging
portion operable to connect to the receiving portion of the
flexible cannula body in vivo; and first and second anchors coupled
to the transseptal tip and configured to be deployed from a
contracted state to an expanded state, the first and second anchors
configured to engage opposite sides of a heart tissue in the
expanded state.
2. The cannula assembly of claim 1, wherein the engaging portion of
the transseptal tip has a threaded surface for threadably engaging
the receiving portion of the flexible cannula body.
3. The cannula assembly of claim 1, wherein each of the first and
second anchors further comprises a plurality of struts extending
generally transverse to a lengthwise central axis of the flexible
cannula body.
4. The cannula assembly of claim 3, wherein the plurality of struts
are formed from a superelastic material and are folded to a
position generally parallel with the lengthwise central axis when
in the contracted state and extend to a position transverse to the
lengthwise central axis when in the expanded state.
5. The cannula assembly of claim 4, wherein the superelastic
material is a tubular structure, a wire, or a flat sheet stock.
6. The cannula assembly of claim 3, wherein the plurality of struts
of the second anchor further includes a porous polymeric
structure.
7. The cannula assembly of claim 3, wherein the plurality of struts
of the first anchor further includes a porous polymeric
structure.
8. The cannula assembly of claim 1, wherein the receiving portion
of the flexible cannula body further includes a seal ring that
engages the proximal end of the transseptal tip and forms a
fluid-tight seal within the receiving portion.
9. The cannula assembly of claim 1, wherein at least a portion of
the flexible cannula body is reinforced with a coil or a braid to
increase a torque response of the flexible cannula body.
10. The cannula assembly of claim 9, wherein the distal and
proximal ends of the flexible cannula body are not reinforced.
11. A transseptal tip delivery system in combination with the
cannula assembly of claim 1, further comprising: a delivery
catheter having distal and proximal ends and a lumen extending
therebetween, the distal end including a receiving portion operable
to removably disengage the engaging portion of the transseptal tip
in vivo; and a delivery sheath configured to receive the delivery
catheter and the transseptal tip and move relative thereto for
deploying the first and second anchors into the expanded state.
12. The transseptal tip delivery system of claim 11, wherein the
delivery catheter is configured to move the transseptal tip
relative to the delivery sheath.
13. The transseptal tip delivery system of claim 11 further
comprising: a balloon catheter configured to engage an inner
surface of the transseptal tip and to resist movement of the
transseptal tip from the heart tissue while the receiving portion
of the delivery sheath is disengaged from the engaging portion of
the transseptal tip.
14. The transseptal tip delivery system of claim 11, wherein the
delivery catheter is reinforced with a coil or a braid along at
least a portion of its length to increase a torque response of the
delivery catheter.
15. A cannula guide in combination with the cannula assembly of
claim 1, comprising: an expandable member having distal and
proximal tapers and an alignment section therebetween; and a body
extending proximally from the expandable member, the expandable
member configured to engage an inner surface of the transseptal tip
and to resist movement of the transseptal tip from the heart tissue
while the receiving portion of the flexible cannula body is
connected to the engaging portion of the transseptal tip.
16. The cannula guide of claim 15, wherein the proximal taper is
configured to direct the receiving portion of the flexible cannula
body to the engaging portion of the transseptal tip.
17. The cannula guide of claim 15, wherein the expandable member
includes a distal portion for engaging the inner surface of the
transseptal tip and a proximal portion having a diameter that is
less than a diameter of the distal portion.
18. A method of implanting a cannula assembly within a heart
tissue, the cannula assembly including a flexible cannula body
having distal and proximal ends with a lumen extending
therebetween, the distal end including a receiving portion, a
transseptal tip having distal and proximal ends, the proximal end
including an engaging portion operable to connect to the receiving
portion of the flexible cannula body in vivo, and first and second
anchors coupled to the transseptal tip, the first and second
anchors configured to be deployed from a contracted state to an
expanded state and to engage opposite sides of the heart tissue,
the method comprising: (a) introducing the transseptal tip into the
heart tissue; (b) directing the flexible cannula body to the
transseptal tip; and (c) in vivo connecting the receiving portion
of the flexible cannula body to the engaging portion of the
transseptal tip.
19. The method according to claim 18, wherein connecting includes
threadably engaging the receiving portion of the flexible cannula
body to the engaging portion of the transseptal tip.
20. The method according to claim 19, wherein the engaging portion
of the transseptal tip includes a threaded surface for threadably
engaging the receiving portion of the flexible cannula body.
21. The method according to claim 18, wherein introducing the
transseptal tip further comprises: directing the transseptal tip to
the heart tissue; and deploying the first and second anchors to
engage the opposite sides of the heart tissue in the expanded
state.
22. The method according to claim 21, wherein the deploying of the
first and second anchors further includes deploying a plurality of
struts of the first and second anchors from a position generally
parallel with a lengthwise central axis of the flexible cannula
body to a position generally transverse to the lengthwise central
axis.
23. The method according to claim 22, wherein the plurality of
struts are formed from a superelastic material.
24. The method according to claim 22, wherein deploying the
plurality of struts further includes deploying a porous polymeric
structure to engage at least one side of the heart tissue.
25. The method according to claim 18, wherein directing the
transseptal tip further comprises: threadably engaging a receiving
portion of a delivery catheter to the engaging portion of the
transseptal tip; and advancing the delivery catheter with the
transseptal tip to the heart tissue.
26. The method according to claim 25 further comprising: advancing
a delivery sheath through the heart tissue, the delivery sheath
including proximal and distal ends and a lumen therebetween;
back-loading the delivery catheter with the transseptal tip through
the lumen of the delivery sheath to the heart tissue; deploying the
first anchor by advancing the delivery catheter with the
transseptal tip beyond the distal end of the delivery sheath; and
deploying the second anchor by retracting the delivery sheath.
27. The method according to claim 26 further comprising:
disengaging the delivery catheter from the transseptal tip; and
retracting the delivery catheter from the heart tissue.
28. The method according to claim 26 further comprising: advancing
an anchoring guide-element through the delivery catheter and the
transseptal tip before deploying the first anchor, the anchoring
guide-element including a body portion having a distal end and a
proximal end, and an anchoring portion at the distal end of the
body portion, wherein the anchoring portion is configured to be
deployed from a contracted state generally parallel to a lengthwise
central axis of the body portion to an expanded state generally
transverse to the lengthwise central axis and is operable to resist
retraction through the heart tissue; and deploying the anchoring
portion after deploying the first anchor and before deploying the
second anchor.
29. The method according to claim 28, wherein the introducing,
directing, and deploying are performed from a primary incision site
located substantially near a superficial vein of the lower
thorax.
30. The method according to claim 29 further comprising: creating a
secondary incision site substantially near a superficial vein of
the upper thorax; directing a capture device through the secondary
incision site to the primary incision site, the capture device
operable to redirect the body portion of the anchoring
guide-element from the primary incision site to the secondary
incision site; and transferring a proximal end of the body portion
of the anchoring guide-element from the primary incision site to
the secondary incision site and before directing the flexible
cannula body.
31. The method according to claim 30, wherein the superficial vein
of the upper thorax is a subclavian vein, a jugular vein, or a
junction between a subclavian vein and an adjoining jugular vein
and the superficial vein of the lower thorax is a femoral vein.
32. The method according to claim 18, wherein steps (a), (b), and
(c) are performed percutaneously with at least one catheter.
33. The method according to claim 18, further comprising: directing
the transseptal tip to the heart tissue without puncturing a
pericardium or a myocardial wall.
34. The method according to claim 18, wherein the introducing,
directing, and deploying are performed from a primary incision site
located substantially near a superficial vein of the lower
thorax.
35. The method according to claim 18 further comprising: directing
a cannula guide to the transseptal tip before directing the
flexible cannula body, the cannula guide comprising an expandable
member having distal and proximal tapers and an alignment section
therebetween and a body extending proximally from the expandable
member.
36. The method according to claim 35, wherein the distal taper and
at least a portion of the alignment section traverse the lumen of
the transseptal tip.
37. The method according to claim 35, wherein the alignment section
contacts an inner surface of the transseptal tip.
38. The method according to claim 35, wherein the proximal taper
guides the flexible cannula body onto the transseptal tip.
39. The method according to claim 35, wherein the expandable member
includes a distal portion and a proximal portion having a diameter
that is less than a diameter of the distal portion, wherein the
method further comprises: inflating the expandable member such that
the distal portion engages an inner surface of the transseptal
tip.
40. An introducer assembly for introducing surgical devices into
the vascular system, the introducer assembly comprising: a
removable dilator having an attachment mechanism; and an introducer
including a hub and a sheath extending distally from the hub, the
introducer operable to receive the dilator in a movable manner and
to maintain a puncture through a vascular wall.
41. The introducer assembly of claim 40, wherein the hub of the
introducer further includes a hemostatic seal, a grommet, or an
O-ring.
42. The introducer assembly of claim 40, wherein the removable
dilator and the introducer are attached together with a frictional
fit operable to prevent leakage of blood from the vascular
system.
43. The introducer assembly of claim 40, wherein the introducer set
includes a sheath introducer, a vascular dilator, and a
guide-wire.
44. A method of introducing a surgical device into the vascular
network of a patient with an introducer assembly, the introducer
assembly including a removable dilator having an attachment
mechanism for removably attaching an introducer set and an
introducer including a hub and a sheath extending distally from the
hub, the method comprising: attaching the introducer set to the
attachment mechanism of the removable dilator, the introducer set
including a sheath introducer, a vascular dilator, and a
guide-wire; receiving the removable dilator and the introducer set
into the introducer; creating a puncture in a vessel wall of a
blood vessel with the guide-wire; advancing the introducer assembly
over the guide-wire and into the blood vessel, thereby dilating the
vessel wall until the hub of the introducer contacts an external
surface of the blood vessel; removing the removable dilator and the
introducer set; and directing the surgical device through the
introducer and into the blood vessel.
45. The method according to claim 44, wherein the directing of the
surgical device further includes opening a hemostatic seal within
the hub of the introducer.
46. The method according to claim 44 further comprising: sealing a
proximal end of the hub of the introducer after removing the
removable dilator.
47. A method of in vivo coupling a flexible cannula body to a
transseptal tip, the flexible cannula body having distal and
proximal ends with a lumen extending therebetweeen, the distal end
including a receiving portion having a first marker, and the
transseptal tip having distal and proximal ends, the proximal end
including an engaging portion having a second marker, the method
comprising: directing the flexible cannula body to the transseptal
tip; in vivo localizing the first and second markers; coupling the
receiving portion of the flexible cannula body to the engaging
portion of the transseptal tip; and continuing the coupling until
the first marker overlays the second marker.
48. The method of in vivo coupling according to claim 47, wherein
the coupling includes threadably engaging the receiving portion of
the flexible cannula body to the engaging portion of the
transseptal tip.
49. The method of in vivo coupling according to claim 47, wherein
the coupling includes magnetically attaching the receiving portion
of the flexible cannula body to the engaging portion of the
transseptal tip.
50. A method of aligning a flexible cannula body to a transseptal
tip, in vivo, the flexible cannula body having distal and proximal
ends with a lumen extending therebetween, the distal end including
a receiving portion, and the transseptal tip having distal and
proximal ends, the proximal end including an engaging portion, the
method comprising: directing a cannula guide to the transseptal
tip, the cannula guide comprising an expandable member having
distal and proximal tapers and an alignment section therebetween
and a body extending proximally from the expandable member, the
alignment section configured to engage an inner surface of the
transseptal tip and to resist movement of the transseptal tip;
inflating the expandable member such that the expandable member
engages the inner surface of the transseptal tip; and advancing the
flexible cannula body over the proximal taper to the engaging
portion of the transseptal tip.
51. The method according to claim 50, wherein the inflating
includes inflating distal and proximal portions of the expandable
member such that the distal portion engages the inner surface of
the transseptal tip and the proximal portion is inflated to a
diameter that is less than a diameter of the distal portion.
52. A stepped balloon for in vivo alignment of a cannula to a
trans-tissue device, the stepped balloon comprising: an expandable
member having distal and proximal tapers and an alignment section
therebetween, the alignment section having a distal portion and a
proximal portion that is expandable to a diameter that is less than
a diameter of the distal portion, the alignment section configured
to engage an inner surface of the trans-tissue device; and a body
extending proximally from the expandable member.
53. A method of removing a circulatory assist device, the
circulatory assist device including a transseptal tip, a pump, and
a flexible cannula body extending proximally from the transseptal
tip to the pump, the method comprising: disengaging the flexible
cannula body from the pump; uncoupling the flexible cannula body
from the transseptal tip; retracting the flexible cannula body; and
sealing the transseptal tip.
54. The method according to claim 53 further comprising: advancing
a cannula guide to the transseptal tip before uncoupling the
flexible cannula body from the transseptal tip, the cannula guide
comprising an expandable member having distal and proximal tapers
and an alignment section therebetween and a body extending
proximally from the expandable member, the alignment section
configured to engage an inner surface of the transseptal tip.
55. The method according to claim 53, wherein the sealing further
includes directing a closure device to the transseptal tip and
deploying the closure device to seal a lumen of the transseptal
tip.
56. The method according to claim 55, wherein the closure device is
an atrial septal defect closure device.
Description
[0001] This application claims the priority of U.S. Provisional
Patent Application Ser. No. 61/163,931, filed on Mar. 27, 2009
(pending), the disclosure of which is incorporated by reference
herein.
TECHNICAL FIELD
[0002] The present invention generally relates to a method of
implanting a circulatory assist system, and more particularly, to
the method of implanting a cannula assembly of the circulatory
assist system.
BACKGROUND
[0003] The human heart is the muscle that is responsible for
pumping blood throughout the vascular network. Veins are vessels
that carry blood toward the heart while arteries are vessels that
carry blood away from the heart. The human heart consists of two
atrial chambers and two ventricular chambers. Atrial chambers
receive blood from the body and the ventricular chambers, which
include larger muscular walls, pump the blood from the heart. A
septum separates the left and the right sides of the heart. Blood
from the veins of the vascular network enters the right atrium from
the superior and inferior vena cava and moves into the right
ventricle. From the right ventricle, the blood is pumped to the
lungs via pulmonary arteries to become oxygenated. Once the blood
has been oxygenated, the blood returns via pulmonary veins to the
heart by entering the left atrium. From the left atrium, the blood
enters the left ventricle and is pumped into the aorta and then
into the arteries of the vascular network.
[0004] For the vast majority of the population, the events
associated with the movement of blood happen without circumstance.
However, for many people the heart fails to provide adequate
pumping capabilities. These heart failures may include congestive
heart failure (commonly referred to as heart disease), which is a
condition that results in any structural or functional cardiac
disorder. The structural or functional disorder impairs the ability
of the heart to fill with or pump blood throughout the body.
Presently, there is no known cure for heart disease and long-term
treatment is limited to a heart transplant. With only a little over
2,000 patients receiving a heart transplant each year, and over
16,600 more on the waiting list for a heart, there is a persisting
need for a cure or at the minimum a means of improving the quality
of life of those patients on the waiting list.
[0005] One such means of bridging the time gap while awaiting a
transplant is a circulatory assist system. Circulatory assist
devices were developed over a decade ago and provide assistance to
a diseased heart by way of a mechanical pump. In this way, the
circulation of blood through the vascular network is aided despite
the presence of diseased tissue. Traditionally, these circulatory
assist devices include an implantable pump, a controller (internal
or external), and inflow and outflow tubes connecting the pump to
the vascular network. FDA approved circulatory assist devices may
be used to partially relieve symptoms of breathlessness and fatigue
associated with severe heart failure and can drastically improve a
patient's quality of life.
[0006] However, the conventional surgical process associated with
the circulatory assist system is highly invasive. At the very least
the procedure involves a thoracotomy, i.e., the opening of the
thoracic cavity between successive ribs to expose the internal
organs. More typical is cardiac surgery, generally known as
open-heart surgery, where the sternum is cut and split to expose
the internal organs. Once the thoracic cavity is accessed, the
physician must enter the pleural space and puncture both the
pericardium and the myocardial wall. There are great risks and an
extensive recovery time associated with the invasive nature of the
implantation surgery. As such, some patients with severe symptoms
are not healthy enough for surgery to receive a circulatory assist
system.
[0007] The transseptal cannula, described in related U.S. patent
application Ser. No. 12/256,911, the disclosure of which is
incorporated herein by reference, provides greater accessibility to
the circulatory assist device to those patients that would receive
the most benefit by minimizing the invasiveness of the implantation
surgery. Yet, there continues to be a need to implement additional
features that would further facilitate the delivery of the
transseptal cannula and/or that would allow the physician to
maintain greater control over the transseptal cannula device during
the surgical procedure.
SUMMARY
[0008] In one illustrative embodiment, the present invention is
directed to a cannula assembly. The cannula assembly includes a
flexible cannula body having distal and proximal ends with a lumen
extending therebetween. The distal end of the flexible cannula body
includes a receiving portion. A transseptal tip has a distal end
and a proximal end with an engaging portion. The engaging portion
of the transseptal tip is operable to connect to the receiving
portion of the flexible cannula body, in vivo. First and second
anchors are coupled to the transseptal tip and are configured to be
deployed from a contracted state to an expanded state. The first
and second anchors are also configured to engage opposite sides of
a heart tissue when in the expanded state.
[0009] The first and second anchors can each include a plurality of
struts extending generally transverse to a lengthwise central axis
of the flexible cannula body. The plurality of struts can be formed
from a superelastic material and can be folded to a position that
is generally parallel with the lengthwise central axis when in the
contracted state.
[0010] Another illustrative embodiment of the present invention
includes a transseptal tip delivery system in combination with the
cannula assembly. The transseptal tip delivery system includes a
delivery catheter and a delivery sheath. The delivery catheter has
distal and proximal ends and a lumen extending therebetween. The
distal end of the delivery catheter includes a receiving portion
that is operable to removably disengage the engaging portion of the
transseptal tip in vivo. The delivery sheath receives the delivery
catheter with the transseptal tip and moves relative thereto.
Moving the delivery sheath can deploy the first and second anchors
into the expanded state.
[0011] Another illustrative embodiment of the present invention
includes a cannula guide in combination with the cannula assembly.
The cannula guide includes an expandable member having distal and
proximal tapers and an alignment section therebetween. A body of
the cannula guide extends proximally from the expandable member.
The expandable member of the cannula guide is configured to engage
an inner surface of the transseptal tip and to resist movement of
the transseptal tip from the heart tissue while the flexible
cannula body is connected to the engaging portion of the
transseptal tip, in vivo.
[0012] In another illustrative embodiment of the present invention,
a method of implanting the cannula assembly within a heart tissue
of a patient is provided. The method includes introducing the
transseptal tip to the heart tissue, directing the flexible cannula
body to the transseptal tip, and connecting the receiving portion
of the flexible cannula body to the engaging portion of the
transseptal tip, in vivo.
[0013] The method of implanting can include deploying the first and
second anchors to engage opposite sides of the heart tissue in the
expanded state. The deploying can further include deploying a
plurality of struts comprising the first and second anchors from a
position generally parallel with a lengthwise central axis of the
flexible cannula body to a position generally transverse to the
lengthwise central axis.
[0014] The method of implanting can further include advancing and
deploying an anchoring guide-element after deploying the first
anchor and before deploying the second anchor. The anchoring
guide-element includes a body portion having distal and proximal
ends and an anchoring portion on the distal end of the body
portion. The anchoring portion is configured to be deployed from a
contracted state to an expanded state that is generally transverse
to the length-wise central axis of the body portion. The anchoring
portion in the deployed state resists retraction of the anchoring
guide-element from the heart tissue.
[0015] The steps of introducing, directing, and deploying can be
performed from a primary incision site that is located
substantially near a superficial vein of the lower thorax. The
method can also be transferred from the primary incision site to a
secondary incision site located substantially near a superficial
vein of the upper thorax.
[0016] Another illustrative embodiment of the present invention
includes an introducer assembly for introducing a surgical device
into the vascular system. The introducer assembly includes a
removable dilator and an introducer. The removable dilator has an
attachment mechanism for removably attaching an introducer set. The
introducer receives the removable dilator with the introducer set
and maintains a puncture through the vascular wall.
[0017] In another illustrative embodiment of the present invention,
a method of introducing a surgical device into the vascular network
of a patient with the introducer assembly is described. The method
includes attaching the introducer set to the removable dilator. The
introducer set and removable dilator are received by the
introducer. A guide-wire punctures a vessel wall and the introducer
assembly is advanced over the guide-wire, as a unit, until the hub
of the introducer contacts an external surface of the vessel. The
removable dilator and introducer set are removed and a surgical
device is directed through the introducer and into the vascular
network.
[0018] In yet another illustrative embodiment of the present
invention, a method of in vivo coupling of the flexible cannula
body to the transseptal tip is described. The flexible cannula body
includes a first marker on the receiving portion and the
transseptal tip includes a second marker on the engaging portion.
The method includes directing the flexible cannula body to the
transseptal tip. The receiving portion of the cannula is coupled to
the engaging portion of the transseptal tip until the first marker
overlays the second marker.
[0019] Another illustrative embodiment of the present invention
includes a method of aligning the flexible cannula body to the
transseptal tip, in vivo. The method includes directing a cannula
guide to the transseptal tip. The expandable member of the cannula
guide is inflated to engage the inner surface of the transseptal
tip. The cannula is advanced over the proximal taper of the cannula
guide to the proximal end of the transseptal tip.
[0020] In yet another illustrative embodiment of the present
invention, a method of removing a circulatory assist device is
described. The method includes disengaging the flexible cannula
body from the pump. The flexible cannula body is then uncoupled and
retracted from the transseptal tip. The transseptal tip is then
sealed.
BRIEF DESCRIPTION OF THE FIGURES
[0021] FIG. 1 is a diagrammatic view of an exemplary method of
accessing the intra-atrial septum of the human heart, shown in
cross-section.
[0022] FIG. 1A is an assembled side elevational view of an
introducer assembly, shown in cross-section.
[0023] FIG. 2A is a disassembled side elevational view of a
transseptal access system, including a delivery sheath, a dilator,
and a transseptal needle.
[0024] FIG. 2B is an assembled side elevational view of the
transseptal access system, including the delivery sheath, a
dilator, and the transseptal needle.
[0025] FIGS. 3A-3C are diagrammatic views of an exemplary method of
accessing the left atrium by puncturing the intra-atrial septum of
the human heart, shown in partial cross-section.
[0026] FIG. 4A is a disassembled side elevational view of an
anchoring guide-element and a delivery device for the anchoring
guide-element, shown in partial cross-section.
[0027] FIG. 4B is an assembled side elevational view, in partial
cross-section, of the anchoring guide-element and the delivery
device for the anchoring guide-element.
[0028] FIG. 4C is a diagrammatic view of an exemplary method of
advancing the assembled anchoring guide-element and delivery device
to the left atrium of the human heart, shown in cross-section.
[0029] FIG. 5A is a disassembled side elevational view of a
transseptal tip and a delivery catheter.
[0030] FIG. 5B is an assembled cross-sectional view of the
transseptal tip and the delivery catheter.
[0031] FIG. 5C is a perspective view of the transseptal tip.
[0032] FIG. 5D is an assembled cross-sectional view of the
transseptal tip and the delivery catheter.
[0033] FIG. 5E is a diagrammatic view of an exemplary method of
loading the assembled transseptal tip and delivery catheter into a
hub of a delivery sheath.
[0034] FIGS. 6A-6D are diagrammatic views of an exemplary method of
deploying a first anchor of the transseptal tip and the plurality
of struts of the anchoring guide-element within the left atrium,
shown in cross-section.
[0035] FIG. 6E is a perspective view of the deployed first anchor
of the transseptal tip and the deployed plurality of struts of the
anchoring guide-element within the left atrium.
[0036] FIG. 6F is a diagrammatic view of an exemplary method of
deploying a second anchor of the transseptal tip within the right
atrium, shown in cross-section.
[0037] FIGS. 6G-6H are diagrammatic views of an exemplary method of
removing and retracting the delivery catheter from the transseptal
tip, shown in cross-section.
[0038] FIGS. 6I-6K are diagrammatic views of an exemplary method of
transitioning the anchoring guide-element from a primary incision
site to a secondary incision site, shown in cross-section.
[0039] FIG. 6L is a diagrammatic view of an exemplary method of
advancing a cannula guide to the transseptal tip, shown in
cross-section.
[0040] FIG. 6M is a side elevational view of a flexible cannula
body.
[0041] FIGS. 6N-6O are diagrammatic views of an exemplary method of
advancing and attaching the flexible cannula body to the
transseptal tip, shown in cross-section.
[0042] FIG. 6P is a diagrammatic view of an exemplary method of
removing the cannula guide and anchoring guide-element from the
transseptal tip, shown in cross-section.
[0043] FIG. 6Q is a diagrammatic view of the assembled flexible
cannula body and the transseptal tip implanted within the
intra-atrial septum, shown in cross-section.
[0044] FIG. 6R is a diagrammatic view of an illustrative
circulatory assist system positioned in the human heart, shown in
cross-section.
[0045] FIGS. 7A-7B are diagrammatic views of an exemplary method of
removing the circulatory assist system, shown in cross-section.
[0046] FIGS. 7C-7E are diagrammatic views of an exemplary method of
removing the flexible cannula body from the transseptal tip, shown
in cross-section.
[0047] FIG. 7F is a diagrammatic view of an exemplary method of
sealing the transseptal tip after the flexible cannula body has
been removed, shown in cross-section.
[0048] FIG. 7G is a diagrammatic view of the sealed transseptal tip
after the flexible cannula body has been removed, shown in
cross-section.
DETAILED DESCRIPTION
[0049] Implanting a circulatory assist system can begin with a
percutaneous transseptal crossing procedure. FIG. 1 illustrates a
portion of the procedure where the physician creates a primary
incision site 10 in a patient 12 that is substantially near a
superficial vein. A suitable superficial vein for the primary
incision site 10 can include a peripheral vein, such as the right
or left femoral veins 18, 22, or others known by one skilled in the
art. It is generally preferred that the primary incision site 10 is
inferior to a secondary incision site 24 that is substantially near
a peripheral vein of the upper thorax, such as the left or right
subclavian veins 26, 30; the left or right jugular veins 34, 38; at
the junction between the left or right subclavian vein 26, 30 and
the adjoining jugular vein 34, 38; or other suitable peripheral
veins known by one skilled in the art.
[0050] The use of a primary incision site 10 is preferred for
accessing a heart tissue, such as an intra-atrial septum 42, due to
the angle of the heart 48 with respect to the inferior vena cava
50. The primary incision site 10 is also well suited for the
embodiments of the present invention because the angle between the
inferior vena cava 50 and the intra-atrial septum 42 allows the
physician to apply greater force for inserting a transseptal tip
(described below) into the intra-atrial septum 42.
[0051] The physician may use a custom introducer assembly to create
and maintain the incision into each of the superficial veins. The
details of the introducer assembly 51 are shown in FIG. 1A and
generally include an introducer 52 and a removable dilator 53 that
are used in cooperation with commercially available introducer
sets, in a manner that is described below.
[0052] The customized introducer 52 includes a hub 54 and a sheath
55 that extends distally from the hub 54. The sheath 55 of the
introducer 52 is constructed from a mid-to-high durometer material
such that the sheath 55, once inserted, does not collapse under the
pressure of the wall of the superficial vein. The sheath material
can be a high density polyethylene having a low coefficient of
friction to ensure that surgical devices move with ease through the
lumen of the introducer 52. Alternatively, a low friction coating
can be applied thereto. In yet other embodiments, the sheath 55 can
include braid or coil structures, formed from materials such as
stainless steel wire, Nitinol, or other materials known in the art,
to provide additional structural stability when needed. Generally,
the sheath 55 of the introducer 52 should be sufficient in length
to extend within the lumen of the superficial vein while the hub 54
remains proximal to the incision site. A suitable length can be
about 10 cm; however, this should not be considered limiting.
[0053] The hub 54 of the introducer 52 includes a sealing
mechanism, illustrated herein as an O-ring 56, for sealing against
the removable dilator 53 or any other subsequently introduced
surgical device. Accordingly, the O-ring 56 should have an inner
diameter that is sufficiently equal to the nominal outer diameter
of the removable dilator 53. Because the O-ring 56 would not
prevent bleeding through the introducer 52 once the removable
dilator 53 has been removed, a silicone plug (not shown) can be
used to seal the hub 54 of the introducer 52 at the O-ring 56.
Alternatively, other sealing mechanisms, such as a hemostatic seal
or a grommet, can be used. The hemostatic seal or grommet would
automatically provide a fluidic seal against the interstitial
pressures when the removable dilator 53 or other surgical device is
not present in the introducer 52.
[0054] FIG. 1A further illustrates the details of the removable
dilator 53, which include a hub 57 and a dilator sheath 58
extending distally from the hub 57. The dilator sheath 58 can be
formed by a melt flow process to create a distal taper 60 as an
attachment mechanism for attaching to an introducer set 61. For
example, the distal taper 60 forms a frictional fit with the
introducer set 61, which is conventionally used for obtaining
vascular access. Suitable introducer sets 61 may include those that
are commercially available, such as the COOK CHECK-FLO PERFORMER
introducer set having a sheath introducer 62, a dilator 63, and a
guide-wire 64. The distal taper 60 can be constructed to fit any
commercially available introducer set 61 having a particular size,
for example those having 12.0 French or 6.0 French dilators. In
some embodiments, the sheath introducer 62 can include a flushing
side-arm port 65 for removing fluid from the incision site.
[0055] Though not specifically shown, the hub 57 of the removable
dilator 53 can include a proximal seal as the attachment mechanism
in alternative or in addition to the distal taper 60. Suitable
proximal seals can include, for example, an O-ring to proximally
couple and seal the removable dilator 53 against the introducer set
61.
[0056] In operation, the commercial introducer set 61 is inserted
through the lumen of the removable dilator 53, which is then, in
turn, loaded into the introducer 52. The guide-wire 64 of the
introducer set 61 is advanced to puncture the wall of the
superficial vein. The introducer set 61, removable dilator 53, and
introducer 52 are then backloaded, as a unit, over the guide-wire
64 and to the wall of the superficial vein. The puncture within the
wall of the superficial vein undergoes a first dilation to a first
diameter with the dilator 63 and then a second dilation to a second
diameter by the removable dilator 53. Finally, with continued
advancement, the sheath 55 of the introducer 52 enters the lumen of
the superficial vein until a distal end of the hub 54 of the
introducer 52 contacts an external surface of the incision site. If
desired, the guide-wire 64 can then be removed from the superficial
vein.
[0057] The introducer 52, removable dilator 53, and introducer set
61 can remain within the wall of the superficial vein, as a unit,
until a larger surgical device is needed. Accordingly, the
physician can decouple the removable dilator 53 with the introducer
set 61, as a unit, from the introducer 52. The introducer 52
remains extended through the wall of the superficial vein to
maintain a vascular network access point, which allows the
physician to advance larger surgical devices into the vascular
network with little to no friction from the contracting wall of the
superficial vein.
[0058] Referring again to FIG. 1, once the primary and secondary
incision sites 10, 24 are made, and the custom introducer assembly
is properly positioned, the physician can direct a capture device,
such as a standard snare device 66, from the secondary incision
site 24, down the superior vena cava 67, the right atrium 68, the
inferior vena cava 50, the right femoral vein 18, and out of the
primary incision site 10. The standard snare device 66 can include
a body 69 that extends between the primary and secondary incision
sites 10, 24 and a snare loop 70 on a distal end of the body 69.
Though not shown, in some embodiments, the snare loop 70 can remain
within the right femoral vein 18 and not extend externally from the
primary incision site 10.
[0059] The method continues with the physician removing the dilator
53 (FIG. 1A) and the introducer set 61 (FIG. 1A) from the hub 54 of
the introducer 52 extending from the primary incision site 10 to
allow passage of a transseptal access system 74 into the vascular
network for making a percutaneous transseptal crossing. The
transseptal access system 74 is then inserted through the snare
loop 70, into the primary incision site 10, up the right femoral
vein 18, the inferior vena cava 50, and into the right atrium 68.
It would be understood that the introducer assembly 51 remains
fully assembled at the secondary incision site 24.
[0060] FIG. 2A illustrates the details of the disassembled
transseptal access system 74, which includes a delivery sheath 78,
a dilator 82, and a transseptal needle 84.
[0061] The delivery sheath 78 has a flexible body 90 with a distal
end, a proximal end, and a lumen extending between. A hub 94 is
positioned on the proximal end of the flexible body 90. The
flexible body 90 of the delivery sheath 78 is custom sized to
facilitate the delivery of a transseptal tip (discussed below) and
can be constructed as three thin-layer walls. The exterior layer
can be constructed of materials such as polyurethane, Nylon-11,
Nylon-12, or PEBAX, thermoplastic elastomers, copolymers, or blends
of urethanes; the interior layer can be a liner made from etched
polytetrafluorethylene (ePTFE), urethane, or Nylon with hydrogel
coating; and the mid-layer can be constructed from a braided
material or a coiled member, such as stainless steel wire, Nitinol,
or polyetheretherketones (PEEK) fibers to provide structural
stability to the flexible body 90. The interior layer, or liner,
can be extruded and placed upon a mandrel with the mid-layer and
the exterior layer respectively formed or otherwise placed over the
interior layer. Polyurethane is then placed over the entire
assembly and heat shrink wrapped over the flexible body 90 for
stability. Alternatively, the flexible body 90 of the delivery
sheath 78 can be laminated by a reflow process. In some instances,
a superelastic coil (nickel titanium, NiTi, or stainless steel) or
a metallic braid can be included to further increase the rigidity
of the delivery sheath 78. The superelastic coil or metallic braid
can enhance the maneuverability of the flexible body 90. A
polymeric layer can surround the superelastic coil or braid to
reduce friction as the flexible body 90 moves within the vascular
network. It would also be permissible for the flexible body 90 to
include a lubricious material, such as HYDROMED or a polyamide, to
reduce friction as a delivery catheter (described below) moves
within the flexible body 90.
[0062] In some embodiments, the flexible body 90 can further
include a marker 98 constructed from a metallic material, such as
gold (Au) or platinum (Pt), or from a polymeric material embedded
with a dense powder, such as tungsten (W). The marker 98 aids the
physician in positioning the delivery sheath 78 in vivo.
[0063] The hub 94 of the delivery sheath 78 can include a main port
102 having a hemostasis valve (described below) to prevent blood
from exiting the delivery sheath 78 during the introduction and/or
removal of other surgical devices, such as the dilator 82. A side
port 106 permits limited fluidic access via a tubing 108 and a
valve 110.
[0064] Referring still to FIG. 2A, the details of the dilator 82
will now be described. The dilator 82 has a dilator body 114, a
dilator tip 118, and a dilator hub 122. The dilator body 114 is
custom sized to facilitate the delivery of the transseptal tip
(discussed below). The dilator body 114 and dilator tip 118 can be
constructed from a polymer with a low coefficient of friction, such
as fluoropolymer. The dilator tip 118 should be constructed with
sufficient rigidity to dilate an opening through the heart tissue.
The dilator hub 122 allows the dilator 82 to be flushed with saline
prior to insertion into the vascular network.
[0065] In some embodiments, it would be permissible for the distal
ends of the delivery sheath 78 and the dilator 82 to include a
preformed shape that is directed toward the intra-atrial septum 42
(FIG. 1).
[0066] FIG. 2A also illustrates the transseptal needle 84, which
can be any device that has a hollow needle tip 126, a hollow needle
body 130, and a needle hub 134, such as the Brockenbrough
transseptal needle. The needle hub 134 can be used in monitoring
the patient's blood pressure while the transseptal needle 84
punctures the intra-atrial septum 42 (FIG. 1).
[0067] FIG. 2B illustrates the assembled transseptal access system
74.
[0068] With the details of the transseptal access system 74
described in some detail, the method of percutaneous transseptal
crossing can continue with reference to FIGS. 3A-3C.
[0069] FIG. 3A illustrates the transseptal access system 74 as the
transseptal needle 84 creates a puncture 138 in the intra-atrial
septum 42 and enters the left atrium 46. The dilator tip 118 is
then advanced over the transseptal needle 84 and dilates the
puncture 138 through the intra-atrial septum 42.
[0070] FIG. 3B illustrates the continued advancement of the dilator
82 such that the puncture 138 is further dilated to a diameter that
is approximately equal to the diameter of the dilator body 114.
This further dilation allows the delivery sheath 78 to advance over
the dilator 82, through the dilated puncture 138, and to enter the
left atrium 46. Once the delivery sheath 78 is within the left
atrium 46, the dilator 82 and the transseptal needle 84 are
retracted, as illustrated in FIG. 3C.
[0071] With the delivery sheath 78 (FIG. 3C) in place, the
physician can then use an anchoring guide-element to aid in the
method of implanting the transseptal tip (discussed below). The
anchoring guide-element may then also be used to facilitate the
redirecting of the implanting procedure from the primary incision
site 10 (FIG. 1) to the secondary incision site 24 (FIG. 1).
[0072] FIG. 4A illustrates an exemplary embodiment of the anchoring
guide-element 142, though additional detail is provided in U.S.
patent application Ser. No. 12/256,911. The anchoring guide-element
142 has a body portion 146 and an anchoring portion 150 on the
distal end of the body portion 146.
[0073] The body portion 146 can be constructed from a central core
made from a metallic material, such as stainless steel or nickel
titanium (NiTi) and covered with a polymeric material to reduce the
friction between the anchoring guide-element 142 and any surgical
device that is advanced over the anchoring guide-element 142. The
body portion 146 should be flexible enough to prolapse upon itself.
The proximal end of the body portion 146 may include an atraumatic
coil 154 constructed from wound radiopaque metal wire (for example,
platinum (Pt)).
[0074] The anchoring portion 150 has a plurality of struts 158
attached to a hub 160. The hub 160 has a tip transition section
162, a strut retaining ring 166, and a tip 170. The tip 170 can be
machined from a dense, radiopaque metallic material, such as
platinum (Pt) or tantalum (Ta), and coated with a material to
prevent galvanic corrosion with the plurality of struts 158. The
tip 170 secures the body portion 146 to the anchoring portion 150
by either laser welding or a chemical bonding process. The strut
retaining ring 166 can be constructed of similar material as the
tip 170 and secures the plurality of struts 158 to the anchoring
portion 150. The tip transition section 162 can be constructed of
similar materials but should be devoid of any sharp edges that may
catch or snag on other surgical devices when removing the anchoring
guide-element 142.
[0075] The plurality of struts 158 can be constructed from a sheet
of superelastic, metallic material (e.g. NiTi) or MP35N, which
allows each of the plurality of struts 158 to be folded and/or held
in a position that is parallel to central axis of the body portion
146. Once released, the plurality of struts 158 will automatically
spring to a deployed state that is transverse to the central axis.
While four struts 158 are shown, this number is not so limited.
Rather, embodiments could be envisioned where two struts or up to
eight struts can be necessitated for a particular physician's needs
or preference.
[0076] Continuing with FIG. 4A, a delivery device 174 for the
anchoring guide-element 142 is shown. A sheath tip 178 of the
delivery device 174 receives the proximal end of the body portion
146 of the anchoring guide-element 142. As the body portion 146 is
pulled through the sheath tip 178 and a sheath body 182, the
plurality of struts 158 contacts the sheath tip 178 and is folded
from the position transverse to the central axis to the position
that is parallel to the central axis. The sheath body 182 is
constructed from etched polytetrafluorethylene (ePTFE) or
fluorinated ethylene propylene (FEP) so as to allow minimal
clearance between the lumen of the sheath body 182 and the body
portion 146 of the anchoring guide-element 142. This construction
facilitates the delivery of the anchoring guide-element 142 because
the body portion 146 construction of the anchoring guide-element
142 lacks sufficient column strength to advance the folded
plurality of struts 158 through the delivery sheath 78 (FIG. 3C) to
the desired location. This minimal clearance can further aid the
physician in deploying the plurality of struts 158.
[0077] FIG. 4B illustrates the anchoring guide-element 142 fully
loaded within the delivery device 174 with the plurality of struts
158 deflected to the position parallel to the central axis. The
delivery device 174 and anchoring guide-element 142 are then ready
to be back-loaded through the hub 94 (FIG. 2A) of the delivery
sheath 78 (FIG. 2A).
[0078] FIG. 4C illustrates the advancement of the delivery device
174 and the anchoring guide-element 142 through the delivery sheath
78 until the distal end of the sheath tip 178 begins to emerge from
the delivery sheath 78.
[0079] The method for implanting the transseptal tip 186 now
continues with reference to FIGS. 5A-5E. FIG. 5A illustrates the
details of the transseptal tip 186, which include a distal end 190
and a proximal end 194 having an engaging portion 198. The engaging
portion 198 is operable to connect to a receiving portion
(described below) of a flexible cannula body (described below) or a
receiving portion of a delivery catheter (described below) in vivo.
In a preferred embodiment, the transseptal tip 186 is constructed
from titanium alloy, such as TiAl 6Va EL 1, by standard turning,
wire electrical discharge machining (EDM), or other machining
processes. Alternatively, the transseptal tip 186 can be
constructed from a polymeric material (for example, nylon) that is
compounded using radiopaque filler that is typically encapsulated
within the polymer matrix. The radiopaque filler can include
platinum-iridium (Pt:Ir), stainless steel, tungsten (W), or
tantalum (Ta) and allows for the in vivo visualization of the
transseptal tip 186 by non-invasive devices, such as X-ray,
real-time fluoroscopy, or intracardiac echocardiograph.
[0080] First and second anchors 202, 206 are coupled to the
transseptal tip 186. The first and second anchors 202, 206 are
configured to be deployed from a contracted state to an expanded
state. Once in the expanded state, the first anchor 202 will engage
the intra-atrial septum 42 (FIG. 1) within the left atrium 46 (FIG.
1) while the second anchor 206 will engage the intra-atrial septum
42 (FIG. 1) within the right atrium 68 (FIG. 1). Additionally, it
is possible to construct the first and second anchors 202, 206 in a
way such that the second anchor 206 is larger than the first anchor
202. This configuration is more desirable than the reverse because
the right atrium 68 (FIG. 1) is larger in volume than the left
atrium 46 (FIG. 1); however, the invention should not be considered
so limited. While the first and second anchors 202, 206 are
described in some detail below, additional details and features are
disclosed in U.S. patent application Ser. No. 12/256,911.
[0081] Continuing with FIG. 5A, the delivery catheter 210 for the
transseptal tip 186 is shown. The delivery catheter 210 has a
proximal end 214 and a distal end 218 that includes a receiving
portion 222. The receiving portion 222 is operable to removably
disengage the engaging portion 198 of the transseptal tip 186 in
vivo. The delivery catheter 210 can be made from a polymer (such as
Pebax or polyurethane) and can be reinforced with a metallic coil
226 or braid (not shown) or stiffening stylet to enhance the
response of the delivery catheter 210. To further increase the
torque response, the coil 226 can be constructed to wind in a
direction that is similar to the direction of rotation used to
disengage the receiving portion 222 from the engaging portion 198.
The delivery catheter 210 can further include a marker 230 near the
distal end 218 of the delivery catheter 210. The marker 230 may be
constructed from a radiopaque material to enhance in vivo
visualization.
[0082] FIG. 5B illustrates the transseptal tip 186 and the delivery
catheter 210 with greater detail. The engaging portion 198 can be
constructed as a low profile, coarse, male thread 232 for
threadably engaging the receiving portion 222 of the delivery
catheter 210 or of the flexible cannula body (described below). The
low profile and coarse construction of the thread 232 aids in
preventing cross threading during the in vivo disassembly of the
transseptal tip 186 from the delivery catheter 210 or during the in
vivo assembly of the flexible cannula body, described in detail
below. The threads 232 can be molded as part of the transseptal tip
186 during construction. Alternatively, the threads 232 are
machined after molding and polished to remove any rough edges.
[0083] In another embodiment, not specifically shown, the engaging
portion 198 can include a first magnet with a polarity that is
opposite to a second magnet on the receiving portion 222 of the
delivery catheter 210. The magnetic field between the first and
second magnets should be sufficiently strong to resist decoupling
without an appropriate amount of force. Generally, the magnetic
field should be sufficiently strong to resist decoupling of the
receiving portion 222 from the engaging portion 198 due to the
frictional force of blood pumping through the transseptal tip 186
and flexible cannula body (described below). Other alternative
means of engaging can include adhesives or frictional fit.
[0084] The distal end 190 of the transseptal tip 186 is shown to
include a shape that will reduce fluidic drag and can be coated
with a material that prevents thrombus growth; however, the
transseptal tip 186 should not be considered to be limited to the
shape specifically shown.
[0085] The transseptal tip 186 also includes a lumen 234 extending
between the distal and proximal ends 190, 194. Once the transseptal
tip 186 is implanted, the lumen 234 creates a shunt through the
intra-atrial septum 42 (FIG. 1).
[0086] The transseptal tip 186 can further include one or more
rings 238 provided for several reasons. These rings 238 can act in
a manner such as to engage the first and second anchors 202, 206.
In this way, the rings 238 can act in conjunction with clamps 242
to affix the first and second anchors 202, 206 on the transseptal
tip 186. The rings 238 could also be used in seating the first and
second anchors 202, 206 and keyed in a way so as to maintain an
orientation of the first and second anchors 202, 206. Suitable
clamps 242 can include configurations as shown or others such as,
but not limited to, swage or crimp-style clamps. The clamps 242
could alternately be attached to the transseptal tip 186 by
adhesive, welding, or tying.
[0087] In construction, the rings 238 can advantageously be molded
as a portion of the transseptal tip 186. Alternatively, the rings
238 are swaged or crimped into place after the transseptal tip 186
is constructed. In some embodiments, the rings 238 can optionally
be constructed of radiopaque materials such as to aid in
localization of the transseptal tip 186. Alternatively, a separate
radiopaque band (not shown) can be constructed and placed
sufficiently near the rings 238.
[0088] FIG. 5B further illustrates that the receiving portion 222
of the delivery catheter 210 may be constructed as the female
counterpart thread 244 to the thread 232 of the engaging portion
198. The threads 244 of the delivery catheter 210 can be
constructed from a radiopaque material to allow for fluoroscopic
visualization, from a polished metallic material (such as titanium
(Ti)), or from a molded polymeric material (such as nylon) that is
compounded using radiopaque filler (such as tantalum (Ta)). The
proximal end of the receiving portion 222 can further include one
or more barbs 246. Barbs 246 provide resistance against the
undesired removal of the receiving portion 222 from the delivery
catheter 210. A tie (not shown) can also be included external to
the delivery catheter 210 at the barbs 246 to further secure the
delivery catheter 210 to the receiving portion 222. In some
embodiments, the proximal end can include a shape that will reduce
fluidic drag; however, the proximal end should not be considered to
be limited to the shape specifically shown.
[0089] FIG. 5C illustrates with greater detail the transseptal tip
186 with the first and second anchors 202, 206. Each of the first
and second anchors 202, 206 generally includes a plurality of
struts 250 extending from a central ring portion (not shown) such
that the plurality of struts 250 and central ring portion are
etched as a single unit from the same piece of superelastic
material. Alternatively, it would be possible to permanently affix
each of the plurality of struts 250 to a separately manufactured
central ring portion, such as by welding or other means. It should
be appreciated that while four struts are shown per anchor 202,
206, this number is not so limited. Rather, embodiments could be
envisioned where fewer or more struts can be necessitated for a
particular physician's needs or preference. Generally, three or
more struts are preferred.
[0090] The first and second anchors 202, 206 can be at least
partially constructed from a superelastic material (such as nickel
titanium (NiTi)) or by chemically etching the parts from flat sheet
stock, electropolishing the etched parts to remove rough edges
generated during the formation process, and then heating the parts
to a superelastic state. While the preferred materials are
specifically taught herein, other suitable biocompatible,
non-compliant, flexible material would be sufficient for the
transseptal tip 186 or the anchors 202, 206.
[0091] FIG. 5C also illustrates that the first anchor 202 can be
offset with respect to the second anchor 206. This is the preferred
configuration of the deployed anchors 202, 206 because of the
particular load-bearing benefits. However, it would also be
possible to include anchors 202, 206 with no offset if the
particular need would arise, though this is not shown.
[0092] As illustrated in phantom in FIG. 5C, the anchors 202, 206
can each respectively include a porous polymeric structure 252 over
the plurality of struts 250. In function, the porous polymeric
structure 252 provides a larger surface to engage the intra-atrial
septum 42 (FIG. 1) than the plurality of struts 250 alone. Further,
the porous polymeric structure 252 allows for tissue in-growth,
where the tissue can grow and become embedded within the porous
polymeric structure 252 to provide greater structural stability and
sealing capacity. While either or both of the anchors 202, 206 can
include the porous polymeric structure 252, it is generally
preferred that only the second anchor 206, which will reside along
the intra-atrial septum 42 (FIG. 1) within the right atrium 68
(FIG. 1), will include the porous polymeric structure 252. This
configuration is preferred because the right atrium 68 (FIG. 1) is
larger in volume than the left atrium 46 (FIG. 1); however, the
invention should not be considered so limited. Suitable materials
for the porous polymeric structure 252 can include, but are not
limited to, polyester monofilament or multifilament yarn; ePTFE
monofilament or multifilament yarn; or fluorinated polyolefin
fibers or yarns, which can be woven, braided, knitted, or felted
into a proper configuration. The porous polymeric structure 252 can
further include various intrinsic configurations including weaves,
braids, or knits having two or three-dimensional honeycombs,
circular, flat, or tri-axial tubular structures. In other
embodiments, the porous polymeric structure 252 can be constructed
from an ePTFE piece in tubular, cylindrical, or sheet form.
Generally, the porous polymeric structure 252 will be constructed
by etching or laser cutting a shape from two sheets of a stock
material (such as those described above). The shaped polymeric
structures 252 are then ultrasonically welded together such that
the shaped polymeric structures 252 capture the plurality of struts
250 therebetween.
[0093] FIG. 5D illustrates the assembled delivery catheter 210 and
transseptal tip 186.
[0094] FIG. 5E illustrates an exemplary method of loading the
assembled delivery catheter 210 and transseptal tip 186 into the
hub 94 of the delivery sheath 78. Because the first and second
anchors 202, 206 naturally expand to a position that is transverse
to the lengthwise central axis, it is necessary to fold the first
and second anchors 202, 206 to a position that is parallel to the
lengthwise central axis and thus suitable for loading the first and
second anchors 202, 206 into the delivery sheath 78. Various
manners of folding the first and second anchors 202, 206 are
disclosed in U.S. patent application Ser. No. 12/256,911; however,
other methods of folding the anchors 202, 206 would be known. For
example, the physician can simply deflect the first anchor 202
distally while the second anchor 206 is deflected proximally. The
proximal and distal folding of the anchors 202, 206 is preferred
because this configuration provides the greatest distance between
the folded anchors 202, 206 and can enhance the physician's control
over the delivery of the anchors 202, 206. A loading tube 254 is
used to open the hemostatic valve 258 within the hub 94 of the
delivery sheath 78 to permit passage of various surgical devices
into the lumen of the delivery sheath 78. The inner diameter of the
loading tube 254 should be sufficiently similar to the inner
diameter of the delivery sheath 78 to create a smooth transition
262 from the loading tube 254 and the delivery sheath 78. A
positive stop (not shown) within the hub 94 provides a tactile
feedback to the physician to ensure that the loading tube 254 is
properly seated prior to advancing the transseptal tip 186. The
loading tube 254 can be constructed from a polymer (fluoropolymer)
that minimizes friction with the transseptal tip 186.
[0095] With the transseptal tip 186 and the anchors 202, 206 now
loaded into the delivery sheath 78, the method of introducing the
transseptal tip 186 to the intra-atrial septum 42 (FIG. 1) can
proceed as shown in FIGS. 6A-6H.
[0096] FIG. 6A illustrates the transseptal tip 186 that has been
advanced to the intra-atrial septum 42 within the right atrium 68.
The transseptal tip 186 can then be advanced to the distal end of
the delivery sheath 78.
[0097] Deploying the first anchor 202, as illustrated in FIG. 6B,
begins with the physician confirming that the transseptal tip 186
is advanced to the distal end of the delivery sheath 78 within the
left atrium 46. The confirmation can be accomplished by in vivo
localization of the marker 230 near the intra-atrial septum 42.
After the confirmation, the delivery catheter 210 and transseptal
tip 186 are advanced further into the left atrium 46 while the
delivery sheath 78 is held in position. In this way, the
transseptal tip 186 extends beyond the delivery sheath 78, and the
first anchor 202 is deployed within the volume of the left atrium
46. Once deployed, the first anchor 202 can have a diameter that is
at least about 1.1 times, but smaller than about 3 times, the
diameter of the puncture 138 through the intra-atrial septum 42
created by the transseptal tip 186; however, the diameter of the
first anchor 202 in the expanded state is limited primarily by the
patient's anatomy. The physician can ensure proper deployment of
the first anchor 202 by in vivo visualization of a radiopaque
marker (not shown) on the plurality of struts 250 of the first
anchor 202.
[0098] Once the proper deployment of the first anchor 202 is
confirmed, the plurality of struts 158 of the anchoring
guide-element 142 can be deployed, as shown in FIG. 6C.
Accordingly, the position of the transseptal tip 186 is maintained
while the anchoring portion 150 of the anchoring guide-element 142
is advanced beyond the sheath tip 178. In this way, the plurality
of struts 158 is deployed within the volume of the left atrium 46.
The physician can ensure proper deployment of the plurality of
struts 158 by in vivo visualization of a radiopaque marker (not
shown) on the plurality of struts 158.
[0099] Once proper deployment of the plurality of struts 158 is
confirmed, the anchoring guide-element 142 and the delivery
catheter 210 with the transseptal tip 186 are retracted until the
plurality of struts 158 contacts the distal end 190 of the
transseptal tip 186 and the first anchor 202 contacts the
intra-atrial septum 42 within the left atrium 46, as shown in FIG.
6D. The delivery device 174 for the anchoring guide-element 142 can
now be fully retracted.
[0100] FIG. 6E illustrates the deployed first anchor 202 and the
deployed plurality of struts 158 with respect to the intra-atrial
septum 42.
[0101] To deploy the second anchor 206, as shown in FIG. 6F, the
physician advances a deflated balloon catheter 266 into the lumen
of the delivery catheter 210. The balloon 270 of the suitable
balloon catheter 266 can be constructed of a compliant to
non-compliant material, including Nylon-11, Nylon-12, polyurethane,
polybutylene terephthalate (PBT), PEBAX, or polyethylene
terephthalate (PET). The balloon 270 is then coupled to the distal
portion of a catheter shaft 274, which can be constructed of the
same or a different material as the balloon 270. Coupling of the
balloon 270 to the catheter shaft 274 can be by thermal bonding,
adhesives, solvent, or covalent bonding. A radiopaque marker (not
shown) can be included upon the distal end of the catheter shaft
274 for providing in vivo localization and alignment of the balloon
270 within the lumen 234 of the transseptal tip 186.
[0102] Once the balloon 270 of the balloon catheter 266 is within
the lumen 234 of the transseptal tip 186, an inflation fluid 271 is
used to inflate the balloon 270 until it contacts the inner
diameter of the transseptal tip 186. This contact may be used to
stabilize the position of the transseptal tip 186 during the
deployment of the second anchor 206.
[0103] To deploy the second anchor 206, the delivery sheath 78 is
retracted once again, while the positions of the transseptal tip
186 (via the delivery catheter 210 and the inflated balloon
catheter 266) and the anchoring guide-element 142 are maintained.
This retraction can be aided by the in vivo visualization of the
marker 98 on the delivery sheath 78. After sufficient retraction,
the second anchor 206 is deployed and engages the intra-atrial
septum 42 within the right atrium 68. The physician can then
confirm that the second anchor 206 is fully deployed by in vivo
visualization of a radiopaque marker (not shown) on the plurality
of struts 250 of the second anchor 206.
[0104] After confirming that the second anchor 206 is fully
deployed and the delivery sheath 78 is fully retracted, the
delivery catheter 210 can be removed from the transseptal tip 186.
To remove the delivery catheter 210, as shown in FIG. 6H, the
balloon catheter 266 remains in contact with the inner surface of
the transseptal tip 186 while the delivery catheter 210 is
uncoupled from the transseptal tip 186 and fully retracted. The
balloon catheter 266 is then deflated and retracted as well.
[0105] As noted above, the use of the primary incision site 10
(FIG. 1) is useful for gaining direct access to the intra-atrial
septum 42 (FIG. 1) and for applying the force necessary to
introduce the transseptal tip 186 (FIG. 5A) to the intra-atrial
septum 42 (FIG. 1). However, the remainder of the surgical
procedure is preferably accomplished from a secondary incision site
24 (FIG. 1). The secondary incision site 24 (FIG. 1) allows the
physician to use a shorter length of flexible cannula body than if
the primary incision site 10 (FIG. 1) had been used; however, the
method should not be considered so limited. The snare device 66
(FIG. 1) is utilized to transition, or move, the operation
procedure from the primary incision site 10 (FIG. 1) to the
secondary incision site 24 (FIG. 1).
[0106] FIG. 6I illustrates the body portion 146 of the anchoring
guide-element 142 extending through the snare loop 70 after the
delivery sheath 78 (FIG. 6H) and the balloon catheter 266 (FIG. 6H)
have been retracted from the primary incision site 10.
[0107] FIG. 6J shows the snare device 66 as the physician begins
retracting the body 69 of the snare device 66 and transitioning
from the primary incision site 10 to the secondary incision site
24. Because the plurality of struts 158 are secured at the
intra-atrial septum 42 within the left atrium 46, the plurality of
struts 158 will resist the removal of the anchoring guide-element
142 from the intra-atrial septum 42. By retracting the snare device
66, a prolapsed portion 278 of the body portion 146 is formed.
After continued retraction of the snare device 66, the proximal end
of the body portion 146 extends through the secondary incision site
24, as shown in FIG. 6K.
[0108] In some embodiments, such as those disclosed in U.S. patent
application Ser. No. 12/256,911, the proximal end of the body
portion 146 could remain extended through the primary incision site
10 while a medial section of the body portion 146 extends
externally from the secondary incision site 24. This embodiment can
prevent an inadvertent application of too much force to the
anchoring portion 150, thereby causing the anchoring portion 150 to
pull through the intra-atrial septum 42.
[0109] With the body portion 146 of the anchoring guide-element 142
extending from the secondary incision site 24, the method of
advancing the flexible cannula body can continue with reference to
FIGS. 6L-6R. However, before the flexible cannula body can be
directed into the secondary incision site 24, the dilator 53 (FIG.
6K) and the introducer set 61 (FIG. 6K) are removed from the hub 54
of the introducer 52 extending from the secondary incision site 24
in a manner that is similar to the methods described above.
[0110] FIG. 6L illustrates the advancement of a cannula guide 282
to the transseptal tip 186, which can be used to align the flexible
cannula body (described below) with the transseptal tip 186. The
cannula guide 282 includes a body 286 and a expandable member 290
having an alignment section 294, a proximal taper 298, and a distal
taper 302. The expandable member 290 can be made from a polymeric
material and is injection molded or blow molded onto the body 286;
however, it is possible to construct the body 286 and the
expandable member 290 separately and adhere the components by a
chemical adhesion process. The distal taper 302 is constructed to
allow the cannula guide 282 to enter the previously implanted
transseptal tip 186 while the proximal taper 298 is constructed to
guide the flexible cannula body onto the alignment section 294 in a
manner that is described in detail below.
[0111] The body 286 can be an extruded polymeric material with a
marker 306 positioned within the alignment section 294 to indicate
the center of the alignment section 294 once assembled. The marker
306 may be constructed from a metallic material, such as gold (Au)
or platinum (Pt) or from a polymeric material embedded with a dense
powder, such as tungsten (W).
[0112] The cannula guide 282 can then be back-loaded over the
anchoring guide-wire 142 and advanced to the transseptal tip 186,
as shown in FIG. 6L. In some embodiments, it may be preferred for
the flexible cannula body (described below) to be back-loaded with
the cannula guide 282, as a unit, over the anchoring guide-element
142. As the cannula guide 282 is slowly advanced, the distal taper
302 enters the transseptal tip 186. Yet further advancement causes
the alignment section 294 to enter the lumen 234 of the transseptal
tip 186.
[0113] With the cannula guide 282 advanced to the transseptal tip
186, the transseptal tip 186 is ready to receive the flexible
cannula body 310. FIG. 6M illustrates the flexible cannula body
310, which includes a proximal end 314 and a distal end 318 having
a receiving portion 322. The walls of the flexible cannula body 310
are preferably constructed from a biodurable, low durometer
thermoplastic or thermoset elastomer material. Specifically, this
can include an extruded aliphatic, polycarbonate base polyurethane;
aliphatic polyether polyurethane; aromatic polyether polyurethane;
aromatic polycarbonate based polyurethane; silicone modified
polyurethane, thermoplastic elastomers, copolymers, or blends of
urethanes; or silicone that will conform to the tortuosity of the
vasculature in which it will reside. At least a portion of the
flexible cannula body 310 can further include a reinforcing member
that provides support and to minimize the chance of kinking. The
reinforcing member may be a metallic coil 326 or braid (not shown)
to enhance the torque response of the flexible cannula body 310. As
described previously with the delivery catheter 210 (FIG. 5A), to
further increase the torque response, the coil 326 can be
constructed to wind in a direction that is similar to the direction
of rotation used to engage the receiving portion 322 to the
engaging portion 198 (FIG. 6N). The reinforcing member will
typically terminate prior to the distal and proximal ends 318, 314
of the flexible cannula body 310 so that the distal and proximal
ends 318, 314 are not reinforced and remain pliable.
[0114] Antimicrobial agents can be embedded within the flexible
cannula body material prior to the forming process to effectively
reduce or eliminate the presence of bio-film and reduce the
potential for infection. Alternatively, the antimicrobial agent may
be applied to the surface of the flexible cannula body 310 after
the molding process is complete.
[0115] In some embodiments, a lubricious coating or layer can be
included on the exterior of the flexible cannula body 310. Such a
lubricious layer would aid in the movement of the flexible cannula
body 310 with respect to the vascular network. Suitable materials
for the layer would include etched polytetrafluorethylene (ePTFE),
fluorinated ethylene propylene (FEP), ethylene vinyl acetate (EVA),
polyvinylidene difluoride (PVDF), high density polyethylene (HDPE),
PEBAX, or polyamide materials coated with a lubricious coating
similar to HYDROMED.
[0116] Once the flexible cannula body 310 is properly formed, it is
cut to the desired length. The pliable proximal end 314 can be
flared for coupling the flexible cannula body 310 to a pump
(described below) of the circulatory assist device. Alternatively,
the proximal end 314 can be formed to be about twice the thickness
of the remainder of the flexible cannula body 310, which can also
assist in coupling the flexible cannula body 310 to the pump of the
circulatory assist device.
[0117] The pliable distal end 318 of the flexible cannula body 310
may also be flared for receiving the engaging portion 198 in a
manner that is described in greater detail below.
[0118] The flexible cannula body 310 can include a marker 330
sufficiently near the receiving portion 322 and made from a dense
metal, such as gold (Au) or platinum (Pt), for providing in vivo
localization of the receiving portion 322.
[0119] Turning now to FIG. 6N illustrating the flexible cannula
body with greater detail, the receiving portion 322 can include an
internal seal ring 342 within a ring groove 346. The seal ring 342,
once assembled with the engaging portion 198, will allow blood flow
to transition smoothly from the transseptal tip 186 to the flexible
cannula body 310, as described in greater detail below. This smooth
blood flow also minimizes the potential for thrombus formation
between the transseptal tip 186 and the flexible cannula body 310.
A lumen transition 350 can also be provided to further minimize the
potential from thrombus formation.
[0120] The receiving portion 322 can be coupled to the flexible
cannula body 310 by any of a variety of means, including mechanical
lock, melt flow, or adhesive bonding. By way of example, the
mechanical lock can be barbs 354 or other external features that
enhance the securement force between the transseptal tip 186 and
the flexible cannula body 310.
[0121] With the details of the flexible cannula body 310 described,
the method of coupling the flexible cannula body 310 to the
transseptal tip 186 continues with reference to FIG. 6N. FIG. 6N
illustrates the cannula guide 282 fully inserted within the lumen
234 of the transseptal tip 186 such that the marker 306 aligns with
the proximal end 194 of the transseptal tip 186. The expandable
member 290 is then inflated such that an outer diameter of a distal
portion 295 of the alignment section 294 engages the inner diameter
of the transseptal tip 186. The expandable member 290, as shown,
can be stepped such that a proximal portion 296 of the alignment
section 294 is expandable to a diameter that is slightly less than
a diameter of the distal portion 295. This configuration allows the
distal portion 295 to contact the inner diameter of the transseptal
tip 186 while maintaining a smaller profile proximal portion 296
that will allow the flexible cannula body 310 to slide over the
cannula guide 282 and couple to the transseptal tip 186. FIG. 6N
also illustrates that in some embodiments, it is permissible for
the distal taper 302 of the cannula guide 282 to extend beyond the
distal end 190 of the transseptal tip 186 and advance the anchoring
portion 150 of the anchoring guide-element 142 slightly distally
from the transseptal tip 186; however, this is not required.
[0122] With the catheter guide 282 positioned within the
transseptal tip 186, the physician can advance the receiving
portion 322 of the flexible cannula body 310 to the engaging
portion 198 within the right atrium 68. The receiving portion 322
has a tapered thread 334 that matches the thread 232 of the
engaging portion 198 of the transseptal tip 186, described
previously. The thread 334 can be a low profile, highly polished,
coarse female thread 334 that prevents cross threading during
engagement of the receiving portion 322 with the engaging portion
198 of the transseptal tip 186. A lead-in 338 to the receiving
portion 322 can be tapered to allow for alignment of the
transseptal tip 186 and the receiving portion 322. The receiving
portion 322 can be a radiopaque material, a polished metallic
material (such as titanium (Ti)), or a molded polymeric material
(such as nylon) that is compounded using radiopaque filler (for
example tantalum (Ta)). In some embodiments, the receiving portion
322 can be coated with a material to prevent thrombus growth.
[0123] FIG. 6O illustrates the attaching of the flexible cannula
body 310 to the transseptal tip 186. The receiving portion 322
initially engages the proximal taper 298 of the cannula guide 282.
With further advancement, the receiving portion 322 engages the
alignment section 294 and eventually the transseptal tip 186. Then,
while the position of the transseptal tip 186 is maintained by the
cannula guide 282, the receiving portion 322 of the flexible
cannula body 310 threadably engages the engaging portion 198 of the
transseptal tip 186 until the marker 330 of the flexible cannula
body 310 is aligned with the marker 306 of the cannula guide 282.
This alignment of the markers 306, 330 ensures full engagement and
seating of the receiving portion 322 onto the engaging portion 198.
With full engagement, two seals are created: an external seal and
an internal seal. The external seal is formed between the receiving
portion 322 and the most proximal clamp 242. The internal seal is
formed between the engaging portion 198 and the seal ring 342.
[0124] Although it is not specifically shown, the inner diameter of
the transseptal tip 186 can be large enough that an embodiment of
the flexible cannula body 310 traverses the lumen of the
transseptal tip 186 and is attached to the distal end 190 of the
transseptal tip 186 within the left atrium 46. Appropriate
attachment means can include screw threads as described above,
magnets, adhesives, or other known means. The attachment can be
strengthened by including a porous polymeric material, such as the
porous polymeric structure 252 (FIG. 5C) described previously with
the first and second anchors 202, 206 (FIG. 5C).
[0125] FIG. 6P illustrates the deflation and retraction of the
cannula guide 282 as well as the retraction of the anchoring
guide-element 142. The anchoring guide-element 142 is removed by
maintaining the position of the transseptal tip 186 by the flexible
cannula body 310 and retracting the body portion 146 of the
anchoring guide-element 142. This retraction movement will force
the anchoring portion 150 against the transseptal tip 186, causing
the deflection of the plurality of struts 158 into the lumen 234 of
the transseptal tip 186. Once the plurality of struts 158 is
deflected, the anchoring guide-element 142 is retracted through the
lumen of the flexible cannula body 310 and out of the secondary
incision site 24 (FIG. 1), leaving the flexible cannula body 310
and transseptal tip 186 implanted, as shown in FIG. 6Q.
[0126] FIG. 6R illustrates the implanted transseptal tip 186 and
the flexible cannula body 310 as a portion of the circulatory
assist system. In that regard, the flexible cannula body 310, which
extends from the transseptal tip 186 to the secondary incision site
24 (via the superior vena cava 67 and right subclavian vein 30), is
attached to the input port 358 of the implantable pump 362. A
separate outflow cannula 366 is attached to an output port 370 of
the implantable pump 362, which is then surgically attached so as
to communicate with a suitable superficial artery, such as the
right subclavian artery 374. At this time, the physician can
position the implantable pump 362 subcutaneously or submuscularly
within the secondary incision site 24 or maintain the pump 362
externally even after the secondary incision site 24 is closed.
[0127] As also shown in FIG. 6R, the pump 362 is operably
associated with a controller 378, which can also be implanted or
remain external to the patient 12. A signal transmission 382 means
is provided between the pump 362 and the controller 378 and can be
either a hard-wired or a wireless communications device. In
operation, the controller 378 can regulate the pumping action of
the pump 362. Additionally, a memory device 386 can be included
within the controller 378 that will record pump activity for
subsequent physician evaluation and interaction.
[0128] The completed flow of blood according to a preferred
embodiment and as shown in FIG. 6R will be as follows: oxygenated
blood will travel from the left atrium 46 via the natural path into
the left ventricle 390 to the aorta 394. From the aorta 394, blood
moves into the left subclavian artery 398, the left common carotid
402, and the brachiocephalic trunk 406, which supplies oxygenated
blood to the right common carotid 410 and the right subclavian
artery 374. Oxygenated blood will also enter the transseptal tip
186 and flexible cannula body 310 from the left atrium 46. Blood
entering the flexible cannula body 310 will travel through the
lumen of the flexible cannula body 310 to the implantable pump 362.
The implantable pump 362 actively pumps blood into the outflow
cannula 366 and into the right subclavian artery 374. From here,
the blood is directed into the remainder of the vascular
network.
[0129] In some patients, there may be a time after the surgery in
which the circulatory assist device is no longer necessary. Thus,
it would be beneficial to remove the unnecessary components, such
as the implantable pump 362 and flexible cannula body 310.
Accordingly, one exemplary method of reversing the procedures is
illustrated in FIGS. 7A-7G.
[0130] The reverse procedure begins, as illustrated in FIG. 7A,
with the physician once again creating an incision near the
secondary incision site 24. It would be appreciated that while this
procedure will be illustrated from the secondary incision site 24,
a similar procedure could also be directed from the primary
incision site 10 (FIG. 1) or any other appropriate incision site
location. It would also be possible for the physician to again use
the introducer assembly 51 (FIG. 1A) at the secondary incision site
24, though this is not shown.
[0131] With the secondary incision site 24 created, the physician
accesses the implantable pump 362 and disconnects the flexible
cannula body 310 from the input port 358 of the implantable pump
362. The flexible cannula body 310 is then sealed with a suitable
cap 411. The physician then cuts and ligates the outflow cannula
366 near the right subclavian artery 374. The implantable pump 362
with the outflow cannula 366 can then be removed from the secondary
incision site 24.
[0132] FIG. 7B illustrates the directing of a guide-wire 412
through the lumen of the flexible cannula body 310 and into the
left atrium 46. While a standard j-shape 413 guide-wire 412 has
been illustrated, it would be understood that other guide-wire
shapes, including the anchoring guide-element 142 (FIG. 4A)
described above, could also be used. Further, while the procedure
has been illustrated with the cap 411 removed, it would be
understood that a suitable sealing device capable of permitting
passage of the guide-wire 412 could also be used.
[0133] FIG. 7B further illustrates the re-advancing of the cannula
guide 282 along the guide-wire 412 to the transseptal tip 186.
[0134] Once the expandable member 290 is within the transseptal tip
186, as shown in FIG. 7C, it is inflated such that the distal
portion 295 of the alignment section 294 contacts the inner
diameter of the transseptal tip 186 and secures the position of the
transseptal tip 186. The proximal portion 296 is stepped such that
the alignment section 294 does not contact an inner surface of the
flexible cannula body 310, which also increases the ease of
removal. With the position of the transseptal tip 186 secured, the
physician can then begin uncoupling the flexible cannula body 310
from the transseptal tip 186. Uncoupling of the flexible cannula
body 310 can occur in a manner that is similar to the method
described previously for uncoupling the delivery catheter 210 (FIG.
6G) from the transseptal tip 186.
[0135] While FIG. 7C illustrates the use of the cannula guide 282
in this exemplary procedure, it would be understood that another
balloon catheter or device could be used to stabilize the position
of the transseptal tip 186 while the flexible cannula body 310 is
removed.
[0136] FIG. 7D illustrates the retraction of the flexible cannula
body 310 from the transseptal tip 186. Subsequently, the expandable
member 290 of the cannula guide 282 is deflated and retracted from
the transseptal tip 186, though this step is not specifically
shown.
[0137] Finally, the present embodiment includes closing off the
shunt created between the left and right atriums 46, 68 by the
transseptal tip 186. One manner of closing off the shunt is for the
physician to direct a closure device 422 over the anchoring
guide-element 142 and through the transseptal tip 186, as
illustrated in FIG. 7E. Appropriate closure devices 422 can include
a distal end 426, a proximal end 430, and a sealing matrix 434
extending therebetween. Suitable commercially available closure
devices can include atrial septal defect closure devices, such as
the BIOSTAR by NMT Medical, Inc. or the AMPLATZER Septal Occluder
by AGA Medical Corp.
[0138] FIG. 7F illustrates the release of the closure device 422
such that the sealing matrix 434 expands to form first and second
fluid-tight seals 436, 438 at the distal and proximal ends 190,
194, respectively, of the transseptal tip 186. Alternatively as
shown in phantom, the first and second fluid-tight seals 440, 442
could extend to include the first and second anchors 202, 206. With
the fluid-tight seals 436, 438 in position, the guide-wire 412 and
any delivery devices 444 associated with the delivery and/or
deployment of the closure device 422 are retracted from the
transseptal tip 186 and the secondary incision site 24 (FIG.
7A).
[0139] With the implantable pump 362 (FIG. 7A) and flexible cannula
body 310 (FIG. 7A) removed, the physician sutures the incisions
created in the right subclavian vein 30 the secondary incision site
24, as shown in FIG. 7G.
[0140] While the present invention has been illustrated by a
description of various preferred embodiments and while these
embodiments have been described in some detail, it is not the
intention of the Applicant to restrict or in any way limit the
scope of the appended claims to such detail. Additional advantages
and modifications will readily appear to those skilled in the art.
The various features of the invention may be used alone or in any
combination depending on the needs and preferences of the user.
This has been a description of the present invention, along with
the preferred methods of practicing the present invention as
currently known. However, the invention itself should only be
defined by the appended claims.
* * * * *