U.S. patent application number 10/613593 was filed with the patent office on 2004-03-11 for distal anastomosis system.
This patent application is currently assigned to Converge Medical, Inc.. Invention is credited to Whayne, James G..
Application Number | 20040049212 10/613593 |
Document ID | / |
Family ID | 25410825 |
Filed Date | 2004-03-11 |
United States Patent
Application |
20040049212 |
Kind Code |
A1 |
Whayne, James G. |
March 11, 2004 |
Distal anastomosis system
Abstract
Distal anastomosis devices and associated methodology are
described herein. Connector and connector components as well as
tools associated therewith are disclosed. The connectors are
preferably adapted to produce an end-to-side anastomosis at a
graft/coronary artery junction. A fitting alone, or a fitting in
combination with a collar may be used as a connector. Each fitting
may be deployed by deflecting its shape to provide clearance for a
rear segment that rotates about adjoining hinge section(s) so to
fit the connector within an aperture formed in a host vessel. Upon
return to a substantially relaxed position, a rear segment anchors
the fitting it in place. The distal fitting may include additional
side features for interfacing with the host vessel/coronary artery.
The collar may include features complimentary to those of a fitting
and provisions for strain relief and securing the graft vessel.
Inventors: |
Whayne, James G.; (Chapel
Hill, NC) |
Correspondence
Address: |
BOZICEVIC, FIELD & FRANCIS LLP
200 MIDDLEFIELD RD
SUITE 200
MENLO PARK
CA
94025
US
|
Assignee: |
Converge Medical, Inc.
|
Family ID: |
25410825 |
Appl. No.: |
10/613593 |
Filed: |
July 2, 2003 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10613593 |
Jul 2, 2003 |
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10251094 |
Sep 20, 2002 |
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10251094 |
Sep 20, 2002 |
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09899346 |
Jul 5, 2001 |
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6626920 |
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Current U.S.
Class: |
606/153 |
Current CPC
Class: |
A61B 2017/1135 20130101;
A61B 17/11 20130101; A61B 17/0206 20130101; A61B 17/064 20130101;
A61B 17/0643 20130101; A61B 17/30 20130101; A61B 2017/1107
20130101; A61B 2017/0243 20130101; A61B 17/068 20130101; A61B
2017/00243 20130101 |
Class at
Publication: |
606/153 |
International
Class: |
A61B 017/08 |
Claims
We claim:
1. A method of creating an anastomosis, comprising: advancing a
leading portion of a fitting into an opening in a host vessel wall;
advancing a rear portion of a fitting in a deflected position into
said opening, said deflected position occurring by torsional
displacement of said rear portion about at least two sections of
said fitting; and forming a connection between said host vessel and
a graft upon return of said distal portion from its deflected
position to a position contacting a wall of said host vessel.
2. The method of claim 1 further comprising forming the opening at
a location along the host vessel wall prior to advancing the
leading portion of the fitting.
3. The method of claim 2 wherein forming the opening comprises
forming a circular or oval opening through the host vessel
wall.
4. The method of claim 1 wherein the leading portion dilates the
opening while being advanced.
5. The method of claim 1 wherein prior to advancing the rear
portion, positioning the rear portion into the deflected position
by rotating the rear portion about the at least two sections.
6. The method of claim 5 wherein rotating the rear portion
configures the fitting into a profile adapted for introduction into
the opening.
7. The method of claim 1 further comprising releasing the rear
portion within a lumen defined within the host vessel prior to
forming the connection.
8. The method of claim 1 wherein forming the connection between the
host vessel and the graft defines an angle ranging from 20.degree.
to 70.degree. between the host vessel and the graft.
9. The method of claim 1 wherein the leading portion and the rear
portion are positioned in line with the host vessel when contacting
the wall of the host vessel.
10. The method of claim 1 wherein forming the connection between
the host vessel and the graft further comprises positioning a
collar over a portion of the graft such that the portion of graft
is urged against the fitting.
11. The method of claim 10 wherein the collar is resiliently
biased.
12. The method of claim 10 further comprising locking the collar
against the fitting via a plurality of interlocking member in
corresponding engagement with the fitting.
13. The method of claim 10 wherein positioning the collar further
comprises compressing a second portion of the graft against the
host vessel.
14. The method of claim 1 wherein prior to advancing the leading
portion of the fitting, configuring the graft such that a portion
of graft material overlaps the host vessel upon forming the
connection between the host vessel and the graft.
15. The method of claim 1 further comprising inspecting the
connection to detect for leakage.
16. The method of claim 1 further comprising adjusting the fitting
or graft.
17. The method of claim 1 further comprising additionally securing
the connection between the host vessel and the graft.
18. The method of claim 17 wherein additionally securing the
connection comprises a method selected from the group consisting of
packing, applying adhesive, and suturing.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This is a continuation of U.S. patent application Ser. No.
09/899,346, filed Jul. 5, 2001, which is incorporated herein by
reference in its entirety.
FIELD OF THE INVENTION
[0002] This relates to producing end-to-side anastomoses,
particularly in communication with coronary arteries. Accordingly,
distal anastomosis fittings and associated devices are
disclosed.
BACKGROUND OF THE INVENTION
[0003] Current techniques for producing anastomoses during coronary
artery bypass grafting procedures involve placing a patient on
cardiopulmonary bypass support, arresting the heart, and
interrupting blood flow in order to suture, clip or staple a bypass
graft to the coronary artery and aorta. However, cardiopulmonary
bypass support is associated with substantial morbidity and
mortality.
[0004] This invention provides devices and methods to avoid bypass
support by allowing for positioning and securing bypass grafts at
host vessel locations without having to stop or re-route blood
flow. In addition, this invention mitigates risks associated with
suturing, clipping or stapling the bypass graft to a host vessel.
This may be accomplished, in part, by features adapted to avoid
bleeding at graft attachment sites and avoiding collapse of a host
vessel around the incision point. Further, the invention optionally
provides features to improve blood flow within a graft and increase
the patency of a graft.
[0005] In performing cardiac bypass surgery, anastomosis sites are
typically provided at a proximal site along a patient's aorta, and
a distal site along a coronary artery beyond a partial or complete
occlusion. Producing an effective anastomosis along a coronary
artery is particularly challenging. The outer diameter of a
coronary artery where a distal anastomosis may be needed can range
from between about 1 mm to about 4 mm in size. By way of
comparison, the outer diameter of the aorta where a proximal
anastomosis may be located ranges between about 20 mm and about 50
mm in size.
[0006] The relatively small size of the site for a distal
anastomosis translates to greater difficulty in a number of ways.
Basic surgical challenges are encountered in dealing with the
smaller vasculature. Further, an interface issue is introduced.
Often, particularly for connection with the smaller coronary
arteries, a graft conduit will have a larger diameter than the host
vessel. This may be due to the need for a larger diameter conduit
to carry adequate blood flow or the result of using a saphenous
vein which must be inverted for use due to its valving, thereby
orienting the larger end of the graft toward the distal site. For
whatever reason, the mis-match in size in joining the graft to the
coronary artery must be dealt with. The present invention is
adapted to handle these issues as well as others as may be apparent
to those with skill in the art. The distal-type connectors
described herein may be employed with precision and speed,
resulting in treatment efficacy not heretofore possible.
SUMMARY OF THE INVENTION
[0007] The invention includes various improvements in end-side
anastomosis systems. Particularly, connectors for producing distal
anatomoses are described. They each include a fitting comprising a
rear section with a segment that deflectable about a hinge section
to allow for placement and securing the device. Curvilinear side
and forward-facing portions are preferred. Most preferably, these
portions are configured to conform to the shape of a host vessel.
Such a fitting may alone serve as a connector between a host vessel
and a graft. Alternately, the connector may comprise a fitting in
combination with a collar adapted to secure a graft to the
fitting.
[0008] Various features for improving the deployability of a
connector, hemostasis at the connector and blood flow through a
graft may be provided by the invention. Further, various tools for
use in preparing for and creating an end-side anastomosis may
comprise part of the invention.
[0009] While connectors and deployment devices according to the
present invention are preferably used in coronary artery bypass
grafting procedures, particularly at a distal location, it is to be
understood that the systems described herein may be used for
purposes other than creating distal anastomoses. The systems may
also be used to produce anastomoses between bypass grafts and host
vessels to treat other occlusions, vascular abnormalities such as
stenoses, thromboses, aneurysms, fistulas and indications requiring
a bypass graft. The system of the present invention is also useful
in bypassing stented vessels that have restenosed, and saphenous
vein bypass grafts that have thrombosed or stenosed. Further, the
invention may have other applications, such as producing arterial
to venous shunts for hemodialysis, bypassing lesions and scar
tissue located in the fallopian tubes causing infertility,
attaching the ureter to the kidneys during transplants, and
treating gastrointestinal defects (e.g., occlusions, ulcers,
obstructions, etc.).
[0010] The present invention variously includes the devices as well
as the methodology disclosed. Furthermore, it is contemplated that
subcombinations of features, especially of the connector features
disclosed, comprise aspects of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] Each of the following figures diagrammatically illustrates
aspects of the present invention. The illustrations provide
examples of the invention described herein. Like elements in the
various figures often are represented by identical numbering. For
the sake of clarity, some such numbering may be omitted.
[0012] FIG. 1 shows a side view of an installed connector according
to the present invention.
[0013] FIG. 2 shows a side view of another installed connector
according to the present invention, this connector including a
collar for securing the graft shown to a fitting.
[0014] FIGS. 3A and 3B show side and end views of a fitting as may
be used according to that shown in FIGS. 1 and 2.
[0015] FIGS. 4A and 4B show side and end views of a collar as may
be used according to that shown in FIG. 2.
[0016] FIGS. 5A-5C show side views of graft vessels as they may be
prepared.
[0017] FIG. 6A shows an oblique view of a guide tool for preparing
a graft vessel.
[0018] FIG. 6B shows a panel of measurement grafts useful to
determine an appropriate length for the graft vessel to be
prepared.
[0019] FIG. 7 shows an oblique view of a spreader.
[0020] FIG. 8 shows an oblique view of a stabilizer.
[0021] FIGS. 9A and 9B show side and top views of a spreader
specifically adapted to open a collar.
[0022] FIG. 10 shows an oblique view of another spreader adapted to
open a collar.
[0023] FIG. 11A show a side view of an instrument with a head
adapted to deploy a connector.
[0024] FIG. 11B shows an alternate head configuration for the
instrument in FIG. 11A, this head configuration adapted for
deploying a connector while holding the instrument at a different
angle.
[0025] FIG. 11C shows an scissors-type head configuration that may
be used with the handle portion of the instrument in FIG. 11A.
[0026] FIG. 12A shows a connector ready for deployment, restrained
in customized Rongeur clamp.
[0027] FIG. 12B shows an oblique view of the top of a lower section
of the instrument in FIG. 12A.
[0028] FIG. 12C shows an oblique view of the underside of an upper
section of the instrument in FIG. 12A.
[0029] FIGS. 13A and 13B show side views of another instrument for
deploying a connector, the instrument positioned in retracted and
extended states, respectively.
[0030] FIG. 14 shows a side view of components to form another
instrument for deploying a connector.
[0031] FIG. 15 shows an oblique view of a end portion for another
instrument for deploying a connector.
[0032] FIGS. 16A-16C show oblique, top and bottom views of a
connector fitting according to the present invention at an
intermediate stage of manufacture.
[0033] FIGS. 17A and 17B, 18A and 18B, and 19-22 show projected
views of optional fitting features.
[0034] FIGS. 23A and 23B, 24A and 24B, 25, 26A-26C and 27A and 27B
show projected views of optional collar features.
DETAILED DESCRIPTION OF THE INVENTION
[0035] The variations of the invention discussed herein are
applicable to robotic surgery and less invasive (i.e., minimally
invasive) surgery involving a thoracostomy or mini median
sternotomy to access the anastomosis site as well as the surgical
approaches, such as that described below. As noted above, the
present invention includes variations of anastomosis connectors
having features adapted to perform distal anastomoses. Anastomosis
connectors, tools and associated methodology for producing proximal
anastomoses are described variously in U.S. and foreign patent and
applications entitled, "Percutaneous Bypass Graft and Securing
System", U.S. Pat. No. 5,989,276; "Percutaneous Bypass Graft and
Securing System", U.S. patent application Ser. No. 09/415,776;
Percutaneous Bypass Graft Securing System", PCT Publication No. WO
98/19625; "Sutureless Anastomosis Systems", U.S. patent application
Ser. No. 09/329,503; "Sutureless Anastomosis Systems", PCT
Publication No. WO 99/65409; "Thermal Securing Anastomosis Systems"
U.S. patent application Ser. No. 09/329,504; "Thermal Securing
Anastomosis Systems", PCT Publication No. WO 99/63910; "Aortic
Aneurysm Treatment Sytems", U.S. patent application Ser. No.
09/329,658; "Aortic Aneurysm Treatment Systems", PCT Publication
No. WO 00/15144; "Additional Sutureless Anastomosis Embodiments",
U.S. patent application Ser. No. 09/654,216; "Improved Anastomosis
Systems", U.S. patent application Ser. No. 09/730,366; "End-Side
Anastomosis Systems", PCT Publicatioin No. WO 01/416653; "Advanced
Anastomosis Systems (II)", U.S. patent application Ser. No.
09/770,560; "Pre-Ionization of Mammalian Implants", U.S.
Provisional Patent Application Serial No. 60/231,368; and
"Sutureless Anastomosis System Deployment Concepts", U.S. Patent
Application Serial No. 60/227,680 and applications and patents
claiming benefit hereto, all commonly owned by Converge Medical,
Inc.
[0036] FIGS. 1 and 2 show distal anastomoses (2) formed by
connectors (4) according to the present invention. Each connector
(4) attaches a graft (6) to a host vessel (8). In this case, the
host vessel is a coronary artery. Graft (6) preferably comprises a
saphenous vein, though a synthetic graft (such as one made of
expanded PTFE) can be utilized. FIG. 1 shows a connector provided
by a fitting (10) only. The connector in FIG. 2 includes a fitting
(hidden) as well as a collar (12).
[0037] Referring to FIG. 1, various features of fitting (10) may be
observed. First, it is noted that fitting and attached graft (6)
are preferably configured so its base or body (14) is at an angle
.alpha. with respect to host vessel (8). Connectors (2) are shown
at approximately a 30.degree. angle. Preferred angles for distal
anastomosis range from about 20.degree. to about 70.degree.. A more
preferable range is from about 30.degree. to about 60.degree.. Most
preferably, they are between about 30.degree. and about 45.degree..
The angle helps maintain hemostasis and proper blood flow once the
anastomosis is created and retracted organs and tissue bear upon
the site. Pressure created by such action will not dislodge
connector (4) or kink or collapse graft (6) since the angle allows
graft (6) to leave the connector (4) and lie substantially in line
with the heart. In addition to improving blood-carry capability of
the conduit in assuring stability of the connector, including some
angle in the connector enables the manner of deployment taught
below.
[0038] Fitting (10) includes at least a front or leading segment
(16) and a rear or trailing segment (18). When situated to form an
anastomosis, these segments lie approximately in line with host
vessel (8). So-placed, they prevent removal of the connector from
the host vessel. Optional lateral or side portions (20) may also
aid in this regard. This is especially the case in forming an
anastomosis with a very small diameter vessel (such as a 1 to 4 mm
diameter coronary artery). Furthermore, lateral portions (20) may
assist in providing a physical barrier to leakage. This may be true
irrespective of the size of host vessel (8). The use of one or more
lateral portions (20) on each side of fitting (10) may also provide
a smooth transition between the leading and trailing portions of
fitting (10) to help moderate or alleviate trauma to the interior
of the host vessel (8).
[0039] A lateral portion may be provided integrally with a form
providing at least part of leading segment (16). Alternately, or
additionally (as shown in FIG. 3A), lateral portions (20) may be
provided in discrete form. Especially when pushed toward the rear
of fitting (10), such a member will work in conjunction with rear
segment (18) to maintain hemostasis at connector (4).
[0040] Additional optional features of fitting (10) include tabs
(22) to assist in securing graft (6) and/or optional collar (12).
Such tabs may be oriented to grip graft (6) as shown in FIG. 1. One
or more tabs may also be adapted to form a locking interface with
one or more complementary tabs (24) optionally included in collar
(12). Also, the height or amount of material incorporated in the
base of the fitting may be varied. In order to utilize as little
material as possible to join the various segments, base (14) may be
provided by a narrow band of material as shown in FIGS. 3A, 16A-16C
or otherwise. To achieve proper relative placement of these
features, base (14) may be curved or undulate.
[0041] As shown in FIG. 3B, the connector opening (26) may have a
circular bore; alternately, it may be ovalized. Configuring fitting
(10) with an ovalized opening (26) may be useful in providing an
interface at a smaller host vessel. It provides a manner in which
to account for the size difference between the vessel and what is
often a larger opening of the graft by. The ovalization increases
the available perimeter to accommodate a host vessel without
increasing the lateral size of the connector. Instead, a connector
is lengthened. This will usually be an acceptable alteration in
connector geometry since only the size of the arteriotomy made in
the host vessel need be lengthened to fit the connector in
place.
[0042] Features that are required of fitting (10), in addition to
the basic leading and trailing segment configuration, are found in
connection with a hinge section (28). Hinge section (28) may be
provided in a number of configurations. However, the configurations
serve the same purpose. Each of the variations shown and described
allow rear segment (18) to be displaced sufficiently to clear the
host vessel wall for insertion of the connector into the host
vessel by significant torsional deflection of areas between rear
segment (18) and fitting body (14). In the fitting variations shown
in FIGS. 1 and 3A and 3B, a pair of torsion sections (30) are
presented on each side of rear segment (18). In the variation in
FIGS. 16A-16C, hinge section (28) includes only one torsion section
(30) on each side of rear segment (18).
[0043] To displace rear segment (18) sufficiently, the primary
deflection does not occur at bend (32) as with the distal
connectors described in U.S. and foreign patents and applications
entitled, "Improved Anastomosis Systems", U.S. patent application
Ser. No. 09/730,366; "End-Side Anastomosis Systems", PCT
Publication No. WO 01/41653; "Advanced Anastomosis Systems (II)"
U.S. patent application Ser. No. 09/770,560. Rather, rotation about
torsional sections accounts for at least half, if not most or
substantially all of the displacement required of rear segment
(18). In the variation of the fitting shown in FIGS. 16A-16C. In
the variation of the fitting shown in FIGS. 16A-16C, rotation of
rear segment (18) occurs about the pair of torsional members (30),
whereas in the variations in FIGS. 1 and 3A and 3B, the rotation
that occurs is shared between two pair of torsional sections.
[0044] Such dual action provides for certain advantages notable in
the variations shown in FIGS. 1, 3A and 3B. Namely, upon forward
deflection of rear segment (18), the lateral portions connected to
torsional sections are caused to be drawn or flexed inward. This
action facilitates introduction of connector (4) into host vessel
(8) by clearing portions that could otherwise interfere with
entry.
[0045] In the variation of the invention shown in FIG. 1, it may be
observed that the torsional regions may be provided either by a
wire segment or simply by a portion of the base of the fitting
reduced to a relatively narrow section by a feature such as a cut,
break, groove or slit (34) in the material. In the variation shown
in FIGS. 16A-16C, no marked reduction in size relative to another
portion of the fitting base is apparent.
[0046] For fittings configured similarly to that in FIGS. 16A-16C,
it is also noted that rotation of members (30) in deflecting rear
section forward will cause lateral portions (20) to be drawn inward
to some extent. However, the amount of inward deflection will be
less relative to the variations of the fitting shown in FIGS. 1 and
3A and 3B where lateral portions (20) are directly connected to
torsional sections.
[0047] Turning now to the features of collar (12), FIGS. 2, 4A and
4B illustrate desirable features of this part of connector (4). A
primary purpose of collar (12) is to secure graft (6) to fitting
(4). As noted above, optional collar tab(s) (24) may assist in this
regard by interfacing with optional fitting tab(s) (22). Also,
collar (12) may be made to be resiliently biased against graft (6)
to hold it to fitting (4). Further, interlocking members (36) may
be provided to ensure a secure fit of collar (12) about fitting
(6). One or more of these interlocking members may take the form of
a hook as shown in FIG. 4A. Provision of a latching mechanism (36)
also eliminates any perceived need to use a locking member such as
a retaining clip, suture, implantable clips, staples, or other
device that might be desired to ensure graft (6) is secured to
fitting (4).
[0048] Collar (12) may comprise at least a proximal band (38) and a
distal band (40). One or more intermediate bands or band segments
(42) may also be provided, upon which optional tabs (24) may be
mounted.
[0049] In the variations of connector (12) shown in FIGS. 2, 4A and
4B, lateral portions (44) are also provided. Preferably, they
overlap or interface with corresponding lateral features (20) of a
complimentary fitting (10) to form a complete seal at an
anastomosis site. Likewise, the shape of the bore of the collar as
shown in FIG. 4B should complement that of the fitting. In
instances where the fitting has a circular bore (26) as shown in
FIG. 3B, at least a mating portion of collar (12) should be
substantially circular as well. In instances where fitting bore
(26) is ovalized, a corresponding shape should be utilized in
collar (12).
[0050] FIG. 12A shows another collar (12) in combination with a
fitting (10). In this collar, the band portions attach to opposite
rib segments (46) at the rear of collar (12). No lateral portions
as shown in the above-referenced figures are included in this type
of fitting. This type of collar functions well with fitting like
those shown in FIG. 1, that only include a pair of lateral portions
(20), instead of two pair like the connectors shown in FIGS. 3A,
and 16A-16C.
[0051] In addition to the collar bands forming part of a structure
to help secure graft (6) to fitting (4), at least the proximal and
distal bands--(38) and (40)--may provide additional utility.
Proximal band (38), possibly in connection with adjacent portions
of collar (12) may be configured to provide a graft/connector
transition allowing for greater blood flow and/or preservation of
the character of a graft, particularly a saphenous vein graft.
[0052] When exposed to arterial blood pressure, saphenous veins may
balloon, producing turbulent flow adjacent to the anastomosis site.
This may lead to hyperplasia or other unwanted physiologic
abnormalities. This tendency is exacerbated by any abrupt
transition in stiffness along its length. Avoidance of ballooning
mitigates the physiologic risks and also ensures a better flow
profile within graft (6).
[0053] To reduce the tendency for a saphenous vein graft to
balloon, proximal band (38) may be of a lower stiffness than
adjacent bands. It is also preferable that it have a curvilinear
shape like that depicted in FIGS. 2 and 4A. Alternately, it may
follow a substantially straight line as viewed from the side as
depicted in FIG. 12A. Either way, it is preferred that band (38)
not run a circumference perpendicular to graft (4). By setting band
(38) askew or by utilizing an undulating form, graft (4) does not
suddenly lack support about an area in which it may easily
balloon.
[0054] As for distal band (40), it may be used to help form a
hemostatic seal between host vessel (8) and graft (6) and/or
connector fitting (10). Preferably, band (40) is designed to bear
down upon a toe portion (48) of graft (6) once inserted into a host
vessel (8). Also, it may be set to bridge any gap between graft (6)
and host vessel (8). Either way, band (40) should grip graft (6) to
ensure its proper location. Such interaction may be aided by the
inclusion of undulating or serrated gripping features (50) in
distal band (40).
[0055] In order to insert connector (4) to complete an anastomosis,
it is preferred that distal band (40) be flexible. In inserting a
connector according to the present invention including a fitting
(10) and collar (12), it is preferably manipulated as shown in FIG.
12A. Here, a modified Rongeur clamp (52) is shown retracting band
(40) and advancing distal segment (18) to prepare the connector for
insertion into an opening in a coronary artery or other appropriate
site. Instrument (52) includes an upper finger (54) and a lower
finger (56), each with relieved interface sections (58) and (60) to
accommodate band (40) and rear segment (18), respectively. Rear
segment (18) extends beyond lower finger (56) to allow
visualization to assist in insertion within host vessel (8).
[0056] Whether prepared in connection with a collar or not,
connector (4) is preferably installed at an anastomosis site as
shown in FIG. 1. Here, it may be observed that graft toe (48)
preferably overlaps host vessel (8). A heel portion (62) may abut,
overlap host vessel (8) or leave a slight gap. When a connector is
provided with a collar (12), the visible result will resemble that
in FIG. 2. Still, the preferred relation of graft (6) to host
vessel (8) remains similar to that shown in FIG. 1, depending on
the fitting configuration selected.
[0057] FIGS. 5A-5C, further illustrate graft preparation
configurations. Graft (6) shown in FIG. 5A is configured like that
shown in FIG. 1. Graft (6) shown in FIG. 5B differs by the
inclusion of an "open" heal section (64); that in FIG. 5C has
"high" heel section (66). The open-heel configuration provides for
graft side extensions (68) offering additional graft material to
overlap a host vessel upon connector insertion. The high-heel
configuration also provides additional graft material to overlap a
host vessel upon connector insertion. By flexing heel (66) outward
to form an increased angle, .beta., heel (66) it is able to overlap
the host vessel above at least a portion of rear segment (18) upon
connector (4) insertion.
[0058] FIG. 6A shows a die (70) with grooves (72) that may be used
to guide a scalpel or other cutting instruments to trim a graft (6)
placed within partial bore (74) to achieve any of the graft
configuration shown in FIGS. 6A-6C. In preparing the graft end
configuration shown in FIG. 5B, a first cut is preferably made at a
45.degree. angle to define the open heel (64). Then a 30.degree.
follow-up cut is made to define side portions (68). In preparing a
graft as depicted in either of FIG. 5A or FIG. 5B, it may also be
desired to create a rear slit. This is currently performed by
taking the graft out of die (70) and manually cutting it with Potts
scissors for a length up to about 4 mm to 10 mm. This allows for
further advancement of graft (6) over fitting (10) to provide
increased coverage.
[0059] A graft/connector combination with at least a distal
connector (4) is preferably prepared before producing the
arteriotomy into which this connector is preferably placed. In
determining the appropriates size of connector (4) and length of
graft, measurements are taken. The size of the connector depends on
the size (particularly the diameter) of graft that is harvested or
otherwise made available for use.
[0060] The length to which graft (6) should be cut may be
determined by simply measuring the distance between anastomosis
target sites. A preferred manner is, however, to take a measurement
by reference to a group or panel (76) of measurement
graft/connector members (78) such as shown in FIG. 6B. Like a panel
of different optics that an optician may use to determine the
proper match for a patient, comparison of different members (78)
provided in panel (76) to the relevant anatomy provides a physician
with the ability to quickly and easily visualize and estimate the
ideal graft length. The length of each unit is advantageously
identified by printing upon each measurement members (78) or in
connection with an optional container (80). Either way, utilizing
measurement members (78) provides a much more accurate gauge of the
proper length of a host vessel since each more realistically spans
the distance between target sites. Most preferably, each member
(78) conforms to anatomy and approximates the angle(s) at one or
both anastomosis sites.
[0061] To achieve such results, measurement members (78) preferably
include a central section (82) adapted to model the compliance of a
graft to be used. Each member also preferably includes an end (84)
adapted to model the properties of a connector according to the
present invention. The opposite end (86) of each member may be
adapted to model a proximal anastomosis connector. A preferred
manner of producing measurement members so-adapted or configured is
with PTFE tubing ranging in diameter from about 2 mm to about 6 mm
and a length between about 60 mm and about 150 mm together with
actual connector members or pressed-in inserts (88). The inserts
may be made of simple plastic pieces or otherwise.
[0062] Now that many of the device features of the invention have
been described, the methodology associated therewith is set forth
in the order in which it is preferred that a surgeon or surgical
team take action to perform a coronary bypass procedure. Variation
of this procedure is, of course, contemplated. Furthermore, it is
to be understood that the devices described herein may be used
outside of this context.
[0063] This being said, after opening a patient and taking a
measurement between intended target sites for proximal and distal
anastomoses or by reference to the panel of measurement members
(78) discussed above, a graft member (6) of sufficient length is
obtained. Typically this will be a saphenous vein. Alternately,
another harvested vessel (such as the lima or radial artery), a
synthetic vessel or a donor vessel may be used as a graft.
[0064] Especially in the case where an organic member is used, the
vessel will be sized to determine the appropriate connector size.
This is preferably done with reference to the inner diameter (90)
of the graft by inserting pins of increasing size (e.g. by 0.25
increments) until the graft no longer easily fits over a given pin.
The size of the largest pin over which graft easily fits over sets
the inner diameter of the graft.
[0065] Next, a connector for producing an anastomosis at a desired
angle, and having an appropriate size is chosen. The size of
fitting (10) and optional collar (12) is preferably the first
incremental size over the inner diameter of the graft. It is
contemplated that connector component sizes may be sized to fit
grafts of a diameter from about 2 mm to about 6 mm progressively,
at 0.5 mm increments.
[0066] Once appropriately sized connector components are chosen, a
graft is skeletonized 10 mm away from the end to be used in
connection with the distal anastomosis. This may be accomplished by
holding the adventitial tissue away from the graft with forceps and
removing selected portions with Potts scissors. At this stage,
graft (6) is cut in such a manner as discussed above and advanced
over fitting (10) into a position as depicted in FIGS. 1, 2 or FIG.
12A.
[0067] Advancing graft (6) over fitting (10) may be accomplished
while holding fitting (10) with a clamp tool (e.g., a hemostat) and
using forceps on either side of graft (6) to pull it over the
fitting. If a collar is included in connector assembly (4), it is
advanced over graft (6) while holding graft end (48) to fitting
front segment (16). Doing so with a clamp tool ensures the
graft/fitting alignment is not changed. Once in place over a
fitting (18), graft (6) may be trimmed to more closely conform to
the shape of connector elements, particularly the exterior of any
collar (12) used. Trimming a graft in this manner may be
particularly appropriate in instances where the graft used is
simply prepared by taking a vessel, cutting it at 90.degree.
relative to its length and then creating a rear slit along its
length as described above.
[0068] A number of spreading mechanisms may be used to hold collar
(12) open to advance it over graft (8). FIGS. 7, 9A, 9B and 10
depict optional spreader devices (92). While spreader (92) in FIG.
7 has additional utility as described below, those depicted in
FIGS. 9A and 9B and 10 are more specialized. The spreader in FIGS.
9A and 9B include an adjustable locking feature (94) as well as
grooves (96) to capture the opposite sides or rib segments (46) of
a collar. The spreader variation shown in FIG. 10, is a modified
clamp. Bracketed ends (98) affixed to an otherwise common implement
provide the means to open collar (12) to place it on graft (6)
loaded onto fitting (10). Such an instrument may be more familiar
to a surgeon, and therefore preferred.
[0069] In placing collar (12) over graft (6), it is to be set in
relation to fitting (10) in a complementary manner. When optional
tabs (22) and (24) are provided, these features can easily be used
to help align a fitting and a collar relative to each other. Either
way, once collar (12) and fitting (10) are properly aligned, collar
(12) is released onto graft (6). Following this, any tabs and/or
locking features (36) are engaged with each other and a final check
is made to ensure accurate component placement and graft
coverage.
[0070] In the event a proximal connector is to be used to complete
a coronary bypass procedure, it may be connected to graft (6) in a
similar fashion or as described variously in the references cited
above. Still, as noted above, a distal connector may alone be used,
with the proximal anastomosis to be accomplished otherwise. While
it need not be the case, the distal connector will preferably be
deployed before making the proximal connection.
[0071] Once a graft/connector combination is prepared, the assembly
is then preferably engaged with a deployment device (52). The
deployment device may be provided as in FIG. 12A, however,
alternate devices are envisioned.
[0072] FIG. 11A shows a deployment device (52) similarly adapted to
draw back band (40) while advancing rear segment (18) in a manner
similar to the deployment device shown in FIG. 12A. Interface
section (58) captures band (40) while hook (100) advances rear
segment (18). To accommodate differences in anatomical access
locations or paths, it is also possible to orient the end of the
deployment device shown in FIG. 11A at another angular orientation
as shown in FIG. 11B. In this case, the instrument head is shown
rotated approximately 90.degree.. It is also noted that the
deployment device in FIG. 11A optionally includes interlocking
members (102) and sprung arms (104), that work in conjunction with
each other to provide a more user-friendly device able to provide a
more stable, user-friendly device to maintain a connector in a
state ready for deployment.
[0073] Alternate deployment mechanisms are portrayed in FIGS. 13A,
13B, 14 and 15. The deployment device in FIGS. 13A and 13B includes
a primary handle (106) and an actuator handle (108). When actuator
handle (108) is advanced, band grasping interface member (110) with
interface section (58) is advanced as shown in FIG. 13B. Pin (112)
within opening (114) limits the extent to which it may be advanced
or withdrawn. When band interface member (110) is retracted as
shown in FIG. 13A, to draw band (40) back from lead segment (16),
the rear segment of a fitting abuts interface section (60) to ready
the connector for deployment.
[0074] FIG. 14 shows another type of deployment device (52). In
this variation, a handle portion (116) and an actuator portion
(118) to be slidably received by handle portion (116) is used by
hooking rear segment (18) in retractor opening (120) and drawing it
into recess (122) when connector (4) is set in receptacle section
(124).
[0075] FIG. 15 shows an end section (126) of yet another type of
deployment device. This variation is adapted for sideways
deployment of a connector. In combination with each other, top and
bottom portions (128) and (130) restrain a connector, compressing
rear section (18) ready for connector deployment. A deployment
mechanism incorporating side-deployment end section (126) may be
advantageously used in situations where access to the host vessel
is hindered by little clearance due to a small thoracic cavity or
difficult vessel orientation. The graft of a graft/connector
combination is received in guide section (132), and stop (134)
limits how deeply the combination may be set into the deployment
device end section (126).
[0076] It is preferred that connector (4) be set and prepared for
deployment within a deployment device before taking invasive action
at the target site for a distal anastomosis. Regardless, a distal
anastomosis site is prepared by creating an initial puncture, for
instance, with the tip of a number 11 blade scalpel. Next, this
opening is preferably extended longitudinally with scissors to
about 3 mm to 7 mm in length depending on the vessel size. Most
often, a longitudinal slit of about 5 mm is preferred. Scissors are
advantageously provided in connection with an instrument as shown
in FIG. 11A, modified with scissors ends (132) as shown in FIG.
11C. Otherwise, standard Potts scissors may be used.
[0077] It may be preferred to use a stabilizing member (134) to
help accomplish the arteriotomy. FIG. 8 shows a suitable device. It
includes a handle (136) and an endpiece (138). A bridge (140)
provides clearance for a coronary artery, while feet (142) are set
against the heart of a patient. Gradations or other indicators in
endpiece (138) help provide a visual indication for creating
appropriately long arteriotomy. Once an arteriotomy of sufficient
length has been created, it is preferably held open by arms (142)
of a spreader (92) as shown in FIG. 7.
[0078] At this stage, connector (4) is deployed. This is preferably
performed by advancing leading section (16) through the
arteriotomoy, and then such lateral features (20) of fitting (10)
as may be provided. Deflected rear segment (18) is then advanced
into host vessel (8) and released to assume a position as shown in
FIG. 1 in order to secure the connector. Particularly in those
variations of the invention as described above where movement of
rear segment articulates side portions (20), movement of rear
segment (18) to an host-vessel engaging position will also cause
affected side portions (20) to engage the sides of host vessel (8)
to maintain connector (4) in place.
[0079] In instances when a collar (12) is used in connector (4), it
is also released to compress front portion (48) of graft (6)
against host vessel (8). Release of collar (12) may also result in
compressing graft (6) against portions of host vessel (8) opposed
by lateral fitting portions (20), especially if complimentary
lateral collar portions (44) are provided.
[0080] Once in place, the completed anastomosis is checked for
leakage. This may be done before and/or after an anastomosis at the
proximal site is complete. At minimum, an inspection of the distal
connection should be made when blood is flowing through graft (6).
If leakage is detected, and it cannot be remedied by adjustment of
the graft or collar, the anastomosis site may be packed or bioglue
(e.g., as available through Cryolife in Kennesaw, Ga.) or a stitch
of suture material may be applied.
[0081] In extremely rare instances where these steps do not prove
adequate, it may be necessary to remove connector (4). After
removing with any supplemental means applied in effort to provide
hemostasis, connector (4) may be removed by reversing the procedure
for its deployment.
[0082] Now, returning to the elements of connector (4), optional
inventive features and a manner of manufacture is described. A
preferred manner of producing connector components according to the
present invention is by machining tubing to include features that
may be bent and set into shape to produce connector elements like
those depicted in FIGS. 1, 2, 3A, 3B, 4A, 4B and 12A. Shapes so
produced may be referred to as wireforms.
[0083] The machining may be accomplished by electron discharge
machining (EDM), mechanically cutting, laser cutting or drilling,
water-jet cutting or chemically etching. It is to be noted that
portions of the connectors may be fabricated as a separate
components and bonded by spot welding, laser welding or other
suitable manufacturing process to form complete structures.
Typically, after whatever cutting or forming procedure is employed,
the material is set in a desired final shape. Where a metal is
used, one or more flexure steps followed by heating will accomplish
this. If the connector elements are made of alternate material such
as a plastic or a composite, other forming procedures as would be
apparent to one with skill in the art may be used.
[0084] Preferably, connector elements are made from a metal (e.g.,
titanium) or metal alloy (e.g., stainless steel or nickel
titanium). Other materials such as thermoplastic (e.g., PTFE),
thermoset plastic (e.g., polyethylene terephthalate, or polyester),
silicone or combination of the aforementioned materials into a
composite structure may alternatively be used. Also, connectors
fabricated from nickel titanium may be clad with expanded PTFE,
polyester, PET, or other material that may have a woven or porous
surface. The fittings may be coated with materials such as paralyne
or other hydrophilic substrates that are biologically inert and
reduce the surface friction. To further reduce the surface tension,
metallic or metallic alloy fittings may be electropolished.
Evidence suggests that electropolishing reduces platelet adhesion
because of the smooth surface. Alternatively, the fittings may be
coated with heparin, thromboresistance substances (e.g.,
glycoprotein IIb/IIIa inhibitors), antiproliferative substances
(e.g., rapamycin), or other coatings designed to prevent
thrombosis, hyperplasia, or platelet congregation around the
attachment point between the bypass graft and the host vessel.
Alternatively, a material such as platinum, gold, tantalum, tin,
tin-indium, zirconium, zirconium alloy, zirconium oxide, zirconium
nitrate, phosphatidyl-choline, or other material, may be deposited
onto the fitting surface using electroplating, sputtering vacuum
evaporation, ion assisted beam deposition, vapor deposition, silver
doping, boronation techniques, a salt bath, or other coating
process.
[0085] A still further improvement of the fittings is to include
beta or gamma radiation sources on the end-side fittings. A beta or
gamma source isotope having an average half-life of approximately
15 days such as Phosphorous 32 or Paladium 103 may be placed on the
base and/or petals of the end-side fitting using an
ion-implantation process, chemical adhesion process, or other
suitable method. Further details as to optional treatments of
connectors according to the present invention are described in
10.00. Of course, connector fitting (10) and any associated collar
(12) may be made differently. To avoid electrolytic corrosion,
however, dissimilar metals should not be used.
[0086] Preferably, NiTi (Nitinol) tubing or flat stock is used to
produce connector components. Irrespective of material format, a
preferred alloy includes a 54.5-57% Ni content, and a remainder Ti
by weight (less minor amounts of C, O, Al, Co, Cu, Fe, Mn, No, Nb,
Si and W) is used. Such alloy has an A.sub.f for at about -10 to
-15.degree. C. Consequently, for typical handling and in use, the
material will exhibit superelastic properties as is most
desired.
[0087] Still, it is contemplated that connectors according to the
present invention may utilize thermoelastic or shape memory
characteristics instead, wherein the material of either or both
fitting (10) and connector (12) change from a martinsitic state to
an austenitic state upon introduction to an anastomosis site and
exposure to a sufficiently warm environment. Taking advantage of
the martinsitic state of such an alloy will ease deflecting rear
segment (18) and lead band (40) and maintaining their positions
until placement.
[0088] Utilizing either thermoelastic or superelastic properties
makes for a connector that can have certain members stressed to a
high degree and return without permanent deformation from a desired
position. However, it is contemplated that either or both fitting
(10) and collar (12) may be made of more typical materials such as
stainless steel or plastic. For fitting (10), this is feasible in
view of the manner in which rear segment (18) is displaced for
insertion into a host vessel. Hinge section (28) permits designs in
which the stress applied by torsion is lower that applied in simply
deflecting a rear petal or segment as shown and described in U.S.
and foreign patents and applications entitled, "Improved
Anastomosis Systems", U.S. patent application Ser. No. 09/730,366;
"End-Side Anastomosis Systems", PCT Publication No. WO 01/41653;
"Advanced Anastomosis Systems (II)" U.S. patent application Ser.
No. 09/770,560.
[0089] This being said, FIGS. 16A-16C show views of a connector
fitting (10) at an intermediate stage of production being made from
tubing. The tube stock used to prepare distal connector fitting
preferably has an outer diameter between 0.080 and 0.240 in (2 to 6
mm) and a wall thickness between 0.004 and 0.008 in (0.1 to 0.2
mm). Slightly larger diameter stock (or end product) will be used
for each matching collar. The stock thickness for NiTi material
used to form collars will typically have a wall thickness between
about 0.04 in and about 0.08 in. Especially, for fitting (10) where
it is possible to use thin stock in view of strength requirements,
this will be preferred in order to minimally obstruct blood flow
past the fitting. Larger connector components will typically be
made of thick stock to account for increased stiffness required of
such configurations relative to smaller ones.
[0090] In the piece shown in FIGS. 16A-16C, all the various
elements described above in connection with completed fittings may
be observed. However, only rear segment (18) is show set in its
final, formed position. As with the other elements, rear segment
(18) is cut in the tubing and initially appears aligned with the
other features. Then, a technician deflects the segment from its
initial placement in accordance with the arrow associated with
segment (18). To set each element in its pre-operative location,
the material is stressed and held at the desired position while
heated or thermally formed to set its shape. The degree of bend in
rear segment show is so extreme as to require sequential
deflectation and thermal forming steps. As for the other elements
to be set in a deflected shape as indicated by arrows associated
therewith, a single deflection/thermal-forming cycle is
adequate.
[0091] FIGS. 17A and 17B show splayed out views of a fitting
according to the present invention. In interpreting these figures
and those similar to them for the collars, it need only be
appreciated that each flattened form represents a pattern (144) for
cutting tube or flat stock to be shaped into a fitting or
connector. When fitting pattern (144) is cut in tubing, it
completely wraps around the tube forming a seamless piece very
similar to that in FIGS. 16A-16C. When flat stock is used, another
forming step is used to produce a round or ovalized body with which
to work with. The ends of the body may then be joined. Alternately,
any gap or split may be left open to provide a measure of
especially compressibility in the fitting. What is more, it is
contemplated that a gap or split may be formed in a fitting made
from tube stock to provide such compliance to connector.
[0092] One way in which a fitting according to pattern (144) in
FIG. 17A differs from that in FIGS. 16A-16C, however, is by
relieved sections (146) in rear segment (18). This allows for
relatively larger rear lateral portions (20). Fitting pattern (144)
in FIG. 17B includes similar features. It is farther distinguished,
however, by its smaller size suited for cutting into a smaller
diameter tube (or in flat stock) to form a smaller connector (3.0
mm diameter in comparison to 3.5 mm diameter). Due to the smaller
size, of the fitting, a substantially regular opening (26) is
provided. In contrast, the variation in FIG. 17A includes a
nonlinear or irregular opening shape, similar to that shown in
FIGS. 16A-16C. This has been found to advantageously reduce the a
wound-healing/hyperplastic response at the site. Each of the
fitting patterns (144) in FIGS. 17A and 17B include various bands
(148) and runners that provide a sort of latticework or wireform to
give substance to the connector while minimizing material
usage.
[0093] FIGS. 18A and 18B show patterns for connectors that are
similarly constructed. In these, opening (26) becomes less regular
as breaks in the base or body (14) of the fitting are observed. In
a fitting made in accordance with FIG. 18A, those breaks occur in
connection with rear lateral portions (20) and at lead tab (22).
The fitting pattern in FIG. 18A also provides a tang (152) to grab
the heel of a graft to assist in graft loading and/or placement.
The switchback providing each of the lateral portions (20) not only
assists in providing a non-circular or irregular shape to assist
with issues of hyperplastic response, but also provides a measure
of axial flexibility to a fitting including such a feature. The
break in the base of the fitting at lead tab (22) provides a
measure of radial compressibility to the fitting.
[0094] In the fitting variation shown in FIG. 188B, a break at tab
(22) is also provided. However, base (14) provides more complete
support to elements around the fitting. The manner in which rear
lateral portions (20) are attached to rear segment (18) is also
worthy of note. As discussed variously above, such a configuration
allows for actuation of lateral portions connected to the rear
segment. Also, it provides a pair of torsional members (30) on each
side of rear segment (18) around which to hinge.
[0095] FIGS. 19 and 20 show fitting patterns (144) with additional
inventive features. A connector to be formed according to the
pattern in FIG. 19 will have a rear segment (18) that includes an
enlarged end (154). The increased coverage of end (154) may provide
a more secure connection or a relatively less traumatic interface
with host vessel (8). However, unless finely tuned in size,
enlarged end (154) can present clearance challenges in deployment.
Likewise, a tight transition (156) from lead section (16) to
forward side sections (20) may provide some impediment to
introduction through an arteriotomy. A more preferred approach is
shown in connection with FIG. 1 where a more gradual transition is
made between lead segment (16) and side portions (20). Still, such
a profile may be difficult to achieve in relatively large diameter
connectors (i.e., on the order of 6 mm in diameter) such as shown
in FIG. 19.
[0096] Regardless, it is noted that fittings as shown in FIGS. 1,
19 and 20 share a common feature in a relatively discrete front
segment (16) as compared to other fittings shown herein. This may
assist in connector penetration and dilation of an arteriotomy
during insertion. A broader front section (16) as shown in FIGS.
17A-18B may, however, be more advantageous from the perspective of
the hemostasis due to greater coverage area.
[0097] A fitting according to the pattern shown in FIG. 20 includes
further distinguishing characteristics. Here rear segment (18)
originates in a different manner than shown in connection with the
other fittings. In this instance, torsion sections (30) are not
provided in connection with base (14) near opening (26) but are
positioned adjacent lateral portions (20). Provided in this manner,
no medial bend (32) or less bend in segment (18) is required to
place rear segment end (154) in position to fulfill its task. In a
fitting formed with a rear segment (18) oriented according to the
approach in FIG. 20, segment (18) may be flexed outward from the
connector body and set in shape by thermal forming by a single
cycle. To use the fitting, rear segment (18) is flexed backward
rather than forward. Formation of the fitting in this manner
provides advantages in that less stress is applied to rear segment
(18) in thermal forming it as shown in connection with the other
figures. This makes for a stronger fitting, with rear segment less
prone to failure due to high stresses during deflection for
deployment or fatigue.
[0098] The pattern in FIG. 21 provides for a fitting in which a
graft can be sandwiched between outer band (156) and inner band
(158). In this manner, the outer band acts like collar band (40) to
hold graft (6) against host vessel (8). Tab (22) is provided to
help grip graft (6) as shown and described in connection with FIG.
1.
[0099] The pattern in FIG. 22 provides for a fitting with multiple
undulations adapted to provided a measure of both axial and radial
flexibility. Flexible fittings work particularly well with a
collar. Especially in connection with a collar having locking
members, it is useful to be able to compress the fitting when
locking the collar around it so that upon expansion of the collar
around the fitting to its locked limit, a graft is snugly captured
between the fitting and the collar.
[0100] However, another feature of fitting pattern (144) shown in
FIG. 22, makes a fitting so configured well suited for use without
a collar. The absence of a tab at medial portion (160) provides a
surface upon which to apply a bioadhesive to directly attach graft
(6) to the fitting.
[0101] FIGS. 23-27B show patterns (162) for creating collars (12).
Collars may be made in a similar fashion to the fittings as
described above. Collars geometry is advantageously set to
correspond in angle to the fitting chosen to form a matched
set.
[0102] FIGS. 23A and 23B show projections to produce collars
substantially as described above. A notable distinction between the
two is the inclusion of locking features (36) in the later
image.
[0103] FIGS. 24A and 24B depict similar collars, except that
additional tabs (24) are included in each. Also the manner of
providing lateral portions (44) differs. The are no longer discreet
members as shown in FIGS. 23A and 23B. Instead, in the variation
shown in FIG. 24A, they are provided in connection with an proximal
section (164) of the collar. In the variation in FIG. 24B, they are
provided in connection with a distal section (166) of the collar.
An advantage of the approach in FIG. 24A is that a stiffer forward
section results providing greater force bearing upon graft (6) for
improved hemostasis. An advantage of the approach in FIG. 24B is
that upward deflection of distal band (40) causes, lateral portions
(44) flex outward to provide additional clearance for connector
insertion.
[0104] FIG. 25 shows a projection (162) configured to provide a
collar (12) with overlapping ends (168). This avoids the production
of a significant seam at the rear of a graft, thereby providing
more support and improving graft patency. Another optional feature
shown in connection with FIG. 25 (see also FIG. 27B) is a distal
band shape intended be a mirror or complement the front portion of
a matching fitting.
[0105] FIGS. 26A-26C show collar projections (162) including
various retention features for grasping a graft (6) in addition to
any tabs (24) provided. The variation in FIG. 26A includes barbs or
tangs (170). The variation in FIG. 26B includes elongate tabs or
fingers (172). The variation in FIG. 26C includes undulations (50)
as described above. The variation in FIG. 26C also includes a
different type of locking mechanism (36) than observed elsewhere in
the figures. A lead-in feature is provided so a simple squeezing
application of force the sides of the collar locks it.
[0106] FIGS. 27A and 27B show examples of other features that may
be included in collars according to the present invention. Fittings
in accordance with each of these projections utilize distal section
(166) to secure a graft about a fitting. The proximal section (164)
in each serves to relieve strain on the graft. By avoiding the use
of a pair or rib segments (46) along the length of the collar as
shown in connection with the collar in FIG. 12A and instead
attaching proximal section features by bridge elements (174),
greater flexibility is achieved for the portion of each fitting
supporting the back of a graft. In the variation shown in FIG. 27A,
the placement of the elements also results in different stiffness
of band sections (176) and (178). In the variation in FIG. 27B,
change in stiffness form one band section to the next is evident in
view of the decreasing size of the material forming the same and
the offset loop (180) and curl (182) features provided.
Alternately, successive loops or curls may be employed. Any of
these features alone, or in combination may comprise a means for
strain relief on a graft. Still further optional features for
collars used in the present invention may include any of those
described in the references cited above.
[0107] The invention has been described and specific examples or
variations of the invention have been portrayed. The use of those
specific examples is not intended to limit the invention in any
way. In all, it is to be understood that each of the features
described in connection with the various connector components and
projections for forming the same may be mixed and matched to form
any number of desirable combinations. Further, it is contemplated
that additional details as to the use or other aspects of the
system described herein may be drawn from Abstract, Field of the
Invention, Background of the Invention, Summary of the Invention,
Brief Description of the Drawings, the Drawings themselves and
Detailed Description and other background that is intended to form
part of the present invention, including any of the patent
applications cited above, each of which being incorporated by
reference herein in its entirety for any purpose. Also, to the
extent that there are variations of the invention which are within
the spirit of the disclosure and are equivalent to features found
in the claims, it is the intent that the claims cover those
variations as well. All equivalents are considered to be within the
scope of the claimed invention, even those which may not have been
set forth herein merely for the sake of relative brevity. Finally,
it is contemplated that any single feature or any combination of
optional features of the inventive variations described herein may
be specifically excluded from the invention claimed and be
so-described as a negative limitation.
* * * * *