U.S. patent application number 09/469717 was filed with the patent office on 2003-09-18 for anastomosis device and method.
Invention is credited to NARCISO, HUGH L. JR..
Application Number | 20030176877 09/469717 |
Document ID | / |
Family ID | 21893106 |
Filed Date | 2003-09-18 |
United States Patent
Application |
20030176877 |
Kind Code |
A1 |
NARCISO, HUGH L. JR. |
September 18, 2003 |
ANASTOMOSIS DEVICE AND METHOD
Abstract
A method for sealingly joining a graft vessel to a target vessel
at an anastomosis site, the target vessel having an opening formed
therein. The method includes positioning a fastener made from a
deformable material radially adjacent to a free end portion of the
graft vessel. The material is transformable between a non-fluent
state and a fluent state, upon application of energy to the
material. The method further includes inserting at least the free
end portion of the graft vessel in the target vessel through the
opening in the target vessel. Energy is then supplied to the
deformable material at an intensity sufficient to transform the
material into the fluent state. The free end portion of the graft
is radially expanded to expand the graft vessel into intimate
contact with an inner wall of the target vessel. The energy supply
is discontinued so that the material returns to its non-fluent
state to sealingly secure the graft vessel to the target
vessel.
Inventors: |
NARCISO, HUGH L. JR.; (PALO
ALTO, CA) |
Correspondence
Address: |
RICHARD SKULA, ESQ.
JOHNSON & JOHNSON
ONE JOHNSON & JOHNSON PLAZA
NEW BRUNSWICK
NJ
08903
US
|
Family ID: |
21893106 |
Appl. No.: |
09/469717 |
Filed: |
December 21, 1999 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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09469717 |
Dec 21, 1999 |
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09037216 |
Mar 9, 1998 |
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6110188 |
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Current U.S.
Class: |
606/153 |
Current CPC
Class: |
A61B 2017/1135 20130101;
A61B 17/11 20130101; A61B 2017/00004 20130101 |
Class at
Publication: |
606/153 |
International
Class: |
A61B 017/08 |
Claims
What is claimed is:
1. A method for sealingly joining a graft vessel to a target vessel
at an anastomosis site, the target vessel having an opening formed
therein, comprising the steps of: positioning a fastener made from
a deformable material radially adjacent a free end portion of said
graft vessel, said material being transformable between a
non-fluent state and a fluent state, upon application of energy to
the material; inserting at least said free end portion of said
graft vessel in said target vessel through the opening in the
target vessel; supplying energy to the deformable material at an
intensity sufficient to transform the material into said fluent
state; radially expanding at least said free end portion of said
graft vessel to expand the graft vessel into intimate contact with
an inner wall of said target vessel; and discontinuing the energy
supply so that the material returns to its non-fluent state to
sealingly secure the graft vessel to the target vessel.
2. The method of claim 1 wherein said energy is selected from a
group consisting of radiant energy, convection heating, conduction
heating, light energy, radiofrequency energy, microwave energy, and
ultrasonic energy.
3. The method of claim 1 wherein said deformable material is
selected from a group consisting of polymerics, polymers, and
copolymers.
4. The method of claim 3 wherein said deformable material is
selected from a group consisting of polyglycotic/polylactic acid
(PGLA) polymer, polyhydroxybutylate valerate (PHBV) polymer,
polycaprolactone (PCL) polymer, polycaprolactone homopolymer, and
polycaprolactone copolymers.
5. The method of claim 1 wherein said material is bioerodable.
6. The method of claim 1 further comprising the step of everting at
least a first portion of said free end portion of the graft vessel
over a portion of said fastener prior to said step of inserting the
graft vessel in the target vessel.
7. The method of claim 6 wherein the step of everting comprises
attaching the first portion of said free end portion of the graft
vessel to the fastener.
8. The method of claim 7 wherein the step of attaching the graft
vessel to the fastener comprises suturing the graft vessel to the
fastener.
9. The method of claim 7 wherein the step of attaching the graft
vessel to the fastener comprises applying an adhesive material to
an external surface of said first portion of said free end portion
of the graft vessel.
10. The method of claim 7 wherein said deformable material has an
adhesive surface and the step of attaching the graft vessel to the
fastener comprises adhering the first portion of the free end
portion of the graft vessel to the fastener.
11. The method of claim 1 wherein said supplying energy step
comprises positioning a distal end portion of a light-diffusing
balloon catheter in said graft vessel.
12. The method of claim 1 wherein said supplying energy step
comprises positioning a distal end portion of a thermal balloon
catheter in said graft vessel.
13. The method of claim 11 wherein said supplying energy step
further comprises irradiating said deformable material with light
energy from an energy source which is coupled to a light-diffusing
end member of said catheter via at least one optical fiber.
14. The method of claim 13 wherein said radially expanding step
comprises inflating a balloon of said balloon catheter.
15. The method of claim 1 wherein said supplying energy step
comprises positioning a distal end portion of a light-diffusing
catheter in said graft vessel.
16. The method of claim 15 wherein said supplying energy step
further comprises irradiating said deformable material with light
energy from an energy source which is coupled to a light-diffusing
end member of said catheter via at least one optical fiber.
17. The method of claim 1 wherein said radially expanding step
comprises inflating a balloon of a balloon catheter.
18. The method of claim 1 wherein said supplying energy step
comprises exposing said material to energy having a wavelength of
between 100 nm and 15,000 nm.
19. The method of claim 1 wherein said supplying energy step
comprises exposing said material to energy having a wavelength of
between 300 nm and 1100 nm.
20. The method of claim 1 wherein said fastener positioning step
comprises positioning a tubular sleeve of said deformable material
over an external surface of said free end portion of said graft
vessel.
21. The method of claim 1 wherein said fastener positioning step
comprises rolling a thin sheet of said deformable material over an
external surface of said free end portion of said graft vessel.
22. The method of claim 1 wherein said fastener positioning step
comprises longitudinally inserting a tubular sleeve of said
deformable material within an opening in said free end portion of
said graft vessel.
23. The method of claim 1 wherein said radially expanding step is
performed prior to said energy supplying step.
24. The method of claim 1 wherein the material is impregnated with
one or more agents selected from the group consisting of
anti-platelet, anti-thrombus, and anti-inflammatory compound.
25. The method of claim 1 wherein the material utilized is
impregnated with one or more anti-proliferative compounds.
26. A method for sealingly joining a graft vessel to a target
vessel at an anastomosis site, the target vessel having an opening
formed therein, comprising the steps of: applying a coating of a
curable material to a free end portion of said graft vessel, said
material being transformable between a fluent state and a
non-fluent state upon application of energy to the material;
inserting at least said free end portion of said graft vessel in
said target vessel through the opening in the target vessel;
radially expanding at least said free end portion of said graft
vessel to expand the graft vessel into intimate contact with an
inner wall of said target vessel; and supplying energy to the
material at an intensity sufficient to transform the material into
its non-fluent state to sealingly secure the graft vessel to the
target vessel.
27. The method of claim 26 wherein said material is
bioerodable.
28. The method of claim 26 wherein said material is selected from a
group consisting of polyethylene-glycol (PEG) based hydrogel,
acrylate, and acrylated urethane.
29. The method of claim 26 wherein said coating comprises a
liquid.
30. The method of claim 26 wherein said coating comprises a viscous
gel.
31. The method of claim 26 wherein the material is impregnated with
one or more agents selected from a group consisting of
anti-platelet, anti-thrombus, and anti-inflammatory compounds.
32. The method of claim 26 wherein the material utilized is
impregnated with one or more anti-proliferative compounds.
33. The method of claim 26 further comprising the step of everting
at least a first portion of said free end portion of the graft
vessel over a portion of said coating.
34. The method of claim 33 further comprising the step of coupling
said first portion of said free end portion to said coating.
35. The method of claim 34 wherein said coupling step includes
suturing said first portion to said graft vessel.
36. The method of claim 34 wherein said curable material has an
adhesive surface and wherein said coupling step comprises adhering
said first portion to said coating.
37. The method of claim 26 wherein said supplying energy step
comprises positioning a distal end portion of a light-diffusing
balloon catheter in said graft vessel.
38. The method of claim 37 wherein said supplying energy step
further comprises irradiating said material with light energy from
an energy source which is coupled to a light-diffusing end member
of said catheter via at least one optical fiber.
39. The method of claim 37 wherein said radially expanding step
comprises inflating a balloon of said balloon catheter.
40. The method of claim 26 wherein said supplying energy step
includes the step of positioning a distal end portion of a
light-diffusing catheter in said graft vessel.
41. The method of claim 40 wherein said supplying energy step
further comprises irradiating said material with light energy from
an energy source which is coupled to a light-diffusing end member
of said catheter via at least one optical fiber.
42. The method of claim 26 wherein said radially expanding step
comprises inflating a balloon of a balloon catheter.
43. The method of claim 26 wherein said supplying energy step
comprises exposing said curable material to ultraviolet radiation
from an ultraviolet radiation energy source.
44. The method of claim 26 wherein said supplying energy step
comprises exposing said curable material to visible light from a
visible light energy source.
45. The method of claim 26 wherein said supplying energy step
comprises exposing said curable material to infrared radiation from
an infrared radiation energy source.
46. An anastomosis device for use in coupling an end of a first
vessel to a side of a second vessel in an anastomosis, the device
comprising a tubular member formed of a deformable material, and a
graft vessel connected to the tubular member, the tubular member
being transformable upon application of energy to the tubular
member between a non-fluent state and a fluent state in which the
tubular member is radially expandable to sealingly engage th e
graft vessel with the target vessel.
47. The anastomosis device of claim 46 wherein the tubular member
is pre-shaped and has at least a first bend along a length of the
member.
48. The anastomosis device of claim 47 wherein the portion of the
tubular member extends at an angle of between 30.degree. and
90.degree. relative to the longitudinal centerline.
49. The anastomosis device of claim 46 wherein said tubular member
is formed from a biocompatible material.
50. The anastomosis device of claim 49 wherein said biocompatible
material is bioerodable.
51. The anastomosis device of claim 46 wherein said biocompatible
material comprises a polymeric material.
52. The anastomosis device of claim 51 wherein said polymeric
material is selected from a group consisting of a polymer, a
homopolymer, and a copolymer.
53. The anastomosis device of claim 52, wherein the polymeric
material is a polycaprolactone.
54. The anastomosis device of claim 46 wherein an end portion of
the graft vessel is everted over an end margin of the tubular
member.
55. The anastomosis device of claim 54 wherein the tubular member
has an adhesive surface and the end portion of the graft vessel is
adhered to the tubular member.
56. The anastomosis device of claim 49 wherein the tubular member
includes a chromophore.
57. The anastomosis device of claim 56 wherein said chromophore is
a dye.
58. The anastomosis device of claim 46 wherein said tubular member
is impregnated with one or more agents selected from the group
consisting of anti-platelet, anti-thrombus, and anti-inflammatory
compounds.
59. The anastomosis device of claim 46 wherein the tubular member
is impregnated with one or more anti-proliferative compounds.
60. A fastener for sealingly joining a graft vessel to a target
vessel in an anastomosis, the target vessel having an opening
formed in a side wall thereof, the fastener comprising a tubular
member formed of a deformable material and sized and dimensioned
for receiving an end portion of said graft vessel, said tubular
member being transformable upon application of energy to the
tubular member between a non-fluent state in which said tubular
member has an outer diameter smaller than the opening in the target
vessel, and a fluent state in which said tubular member is radially
expandable to permit said graft vessel to be forced into sealing
engagement with an inner wall of the target vessel.
61. An anastomosis device for coupling a graft vessel to a target
vessel, the device comprising a graft vessel having a material
disposed on an end margin of a free end thereof, the material being
transformable upon the application of energy to the material
between a fluent state in which the material is radially expandable
to permit radial expansion of the graft vessel, and a non-fluent
state in which the material retains the end margin of the graft
vessel in its expanded state in sealing engagement with the target
vessel.
62. The fastener of claim 61 wherein said material is
bioerodable.
63. The fastener of claim 61 wherein said material is selected from
a group consisting of polyethylene-glycol (PEG) based hydrogels,
acrylates, and acrylated urethanes.
64. The fastener of claim 61 wherein the material is impregnated
with an agent selected from the group consisting of anti-platelet,
anti-thrombus, and anti-inflammatory compounds.
65. The fastener of claim 61 wherein the material is impregnated
with one or more anti-proliferative compounds.
66. The fastener of claim 61 wherein said material is applied to an
outer wall of the graft vessel.
67. The fastener of claim 61 wherein said material is applied to an
inner wall of the graft vessel.
Description
FIELD OF THE INVENTION
[0001] The present invention relates generally to devices and
methods for performing a vascular anastomosis and, more
particularly, to a device for coupling the end of a vessel, such as
a coronary bypass graft, to the side wall of a vessel such as a
coronary artery.
BACKGROUND OF THE INVENTION
[0002] A manifestation of coronary artery disease is the build-up
of plaque within the inner walls of the coronary arteries, which
causes narrowing or complete closure of these arteries, resulting
in insufficient blood flow. This deprives the heart muscle of
oxygen and nutrients, leading to ischemia, possible myocardial
infarction and even death. When angioplasty is excluded from
potential treatments, surgery to alleviate this problem is employed
and often involves creating an anastomosis between a coronary
artery and a graft vessel to restore a blood flow path to essential
tissues. An anastomosis is a surgical procedure by which two
vascular structures, such as a graft vessel and a coronary artery,
are interconnected.
[0003] Current methods available for creating an anastomosis
include hand suturing the vessels together. Connection of
interrupted vessels with stitches has inherent drawbacks. For
example, it is difficult to perform and requires great skill and
experience on the part of the surgeon due in large part to the
extremely small scale of the vessels. For example, the coronary
arteries typically have a diameter in the range of between about 1
to 5 mm, and the graft vessels have a diameter on the order of
about 1 to 4 mm for an arterial graft such as a thoracic artery, or
about 4 to 8 mm for a vein graft such as a saphenous vein. Other
drawbacks of connection with stitches are the long duration of the
operation, during which period in conventional open-heart coronary
artery bypass graft (CABG) surgery the heart is arrested and the
patient is maintained under cardioplegic arrest and cardiopulmonary
bypass. Cardiopulmonary bypass has been shown to be the cause of
many of the complications that have been reported in conventional
CABG, such as stroke. The period of cardiopulmonary bypass should
be minimized, if not avoided altogether, to reduce patient
morbidity.
[0004] One approach to coronary artery bypass grafting that avoids
cardiopulmonary bypass is performing the suturing procedure on a
beating heart in a minimally invasive direct coronary artery bypass
graft ("MIDCAB") procedure. At present, however, safe,
reproducible, and precise anastomosis between a stenotic coronary
artery and a bypass graft vessel presents numerous obstacles
including continuous cardiac translational motion which makes
meticulous microsurgical placement of graft sutures extremely
difficult. The constant translational motion of the heart and
bleeding from the opening in the coronary artery hinder precise
suture placement in the often tiny coronary vessel.
[0005] The above mentioned drawbacks of hand suturing have led to
the development of various approaches to stitchless vascular
connection or anastomosis which has the advantage of quick and
simple execution and undamaged vascular endothelium. Some
approaches to stitchless anastomosis used rigid rings prepared from
various materials. For example, Geotz et al., INTERNAL
MAMMARY-CORONARY ARTERY ANASTOMOSIS--A Nonsuture Method Employing
Tantalum Rings, J. Thoracic and Cardiovasc. Surg. Vol. 41 No. 3,
1961, pp. 378-386, discloses a method for joining blood vessels
together using polished siliconized tantalum rings which are
circumferentially grooved. The free end of the internal thoracic
artery is passed through a ring chosen according to the size of the
stenotic coronary artery. The free end of the thoracic artery is
everted over one end of the ring as a cuff and fixed with a silk
ligature which is tied around the most proximal of the circular
grooves in the ring. The cuffed internal thoracic artery is
inserted into an incision in the target coronary artery. The ring
is fixed in place and sealingly joined to the target coronary
artery by tying one or more sutures circumferentially around the
target vessel and into one or more circular grooves in the ring. An
intima-to-intima anastomosis results.
[0006] The use of metallic coupling rings is also disclosed in
Carter et al., Direct Nonsuture Coronary Artery Anastomosis in the
Dog, Annals of Surgery, Volume 148, No. 2, 1958, pp. 212-218
(describing use of rigid polyethylene rings for stitchless vascular
connections). Moreover, for example, U.S. Pat. No. 4,624,257 to
Berggren et al. describes a device consisting of a pair of rigid
rings each having a central opening through which the end of the
coronary or graft vessel is drawn and everted over the rings. A set
of sharp pins extends outwardly from the face of each ring and
pierce through the vessel wall in the everted configuration. The
rings are then joined together to align the end of the graft vessel
with the opening in the target vessel.
[0007] However, no permanently satisfactory results have been
reported with the use of rigid rings. A rigid ring presents a
foreign body of relatively heavy weight which does not heal well
and produces pressure necrosis. Moreover, the use of rigid rings
that completely encircle the graft vessel and the arteriotomy
creates a severe "compliance mismatch" relative to both the
coronary artery and the graft vessel at the anastomosis site which
could lead to thrombosis. That is, recent studies suggest that the
anastomosis site should not be dramatically different in compliance
relative to either the coronary artery or the vascular graft, which
is the case when using rigid rings to sealingly join two vessels
together.
[0008] Another method currently available for stitchless
anastomosis involves the use of stapling devices. These instruments
are not easily adaptable for use in vascular anastomosis. It is
often difficult to manipulate these devices through the vessels
without inadvertently piercing a side wall of the vessel. Moreover,
as noted above, the scale of the vessels is extremely small, and it
is extremely difficult to construct a stapling device that can work
reliably on such a small scale to provide a consistent and precise
leak-free vascular anastomosis.
[0009] In response to the inherent drawbacks of previous devices
and methods for performing vascular anastomoses, the applicant has
invented a novel device and method for anastomosing vessels using
deformable or curable materials, which can be molded in vivo to
create a shaped article which is capable of sealingly joining a
graft vessel to a target vessel in a patent, compliant anastomosis.
The application of deformable materials to body tissues of humans
to treat various medical conditions has become increasingly
important in medicine. By "deformable," it is meant that the
material may be transformed from a solid, non-fluent state to a
moldable, fluent state in vivo upon the application of energy, such
as light energy or heat, to the material. The deformable material,
for example, may become moldable in vivo by a heat-activated
process upon the application of radiant energy from an energy
source such as a radio frequency energy source, microwave energy
source, ultrasonic energy source, or light energy source at a
predetermined frequency, wavelength or wavelengths. Alternatively,
the deformable material may become moldable by other conventional
heat-activated heating means, such as by conductive heating or
convective heating. In addition, deformable materials that become
moldable by a non-thermal light-activated process without
generating heat also are generally known. Such materials can be
converted to a moldable, fluent state by any one of a number of
light-activated processes, such as a photochemical process or a
photophysical process (i.e., photoacoustic or plasma
formation).
[0010] Alternatively, it is also generally known to use curable
materials, such as an acrylate or an acrylated urethane material,
to bond two materials together, such as body tissue surfaces. A
"curable" material refers to a material that can be transformed
from a generally fluent, or liquid state, to a solid, non-fluent,
cured state upon the application of energy, such as light energy or
heat, to the material. The curable material is preferably applied
to an internal tissue surface in fluent form, as a liquid or
viscous gel. The coated tissue can then be exposed to light, such
as ultraviolet, infrared or visible light, or heat, to cure the
material and render it non-fluent, in situ. If light is used as the
activating medium, the light is selected to be of an appropriate
wavelength and intensity to effectively transform the material from
its fluent state into its non-fluent state. Heat curable materials
can be used in a similar fashion with the method of heating chosen
from the list set forth above for deformable materials.
[0011] Among the various uses of deformable and curable materials
are the prevention of post-operative adhesions, the protection of
internal luminal tissue surfaces, the local application of
biologically active species, and the controlled release of
biologically active agents to achieve local and systemic effects.
They may also be used as temporary or long-term tissue adhesives or
as materials for filling voids in biological materials. The
materials and conditions of application are selected to enhance
desirable properties such as good tissue adherence without adverse
tissue reaction, non-toxicity, good biocompatibility,
biodegradability, and ease of application. Numerous examples of
these materials and their various current uses are fully disclosed
in U.S. Pat. Nos. 5,410,016 to Hubbell et al. and 5,662,712 to
Pathak et al., the entire contents of which are expressly
incorporated by reference herein. However, it is believed that
these materials have not been applied to the field of coronary
artery bypass graft surgery, and more particularly, to performing
vascular anastomoses. Accordingly, a need exists for a simple
method and device for performing a vascular anastomosis using
deformable or curable materials in vivo that avoids the problems
associated with the prior art methods and devices for joining two
vessels together.
SUMMARY OF THE INVENTION
[0012] The present invention involves improvements to methods and
devices for performing vascular anastomoses using deformable or
curable materials in vivo. The invention facilitates sealingly
joining a graft vessel, such as an internal thoracic artery, to a
target vessel, such as a left anterior descending artery.
[0013] A method of the present invention for sealingly joining a
graft vessel to a target vessel at an anastomosis site generally
includes positioning a fastener made from a deformable material
radially adjacent a free end portion of the graft vessel. The
material is transformable between a non-fluent state and a fluent
state upon application of energy to the material. At least the free
end portion of the graft vessel is inserted in the target vessel
through the opening in the target vessel. Energy is supplied to the
deformable material at an intensity sufficient to transform the
material into the fluent state. The free end portion of the graft
vessel is radially expanded to expand the graft vessel into
intimate contact with an inner wall of the target vessel. The
energy supply is discontinued so that the material returns to its
non-fluent state to sealingly secure the graft vessel to the target
vessel.
[0014] In another aspect of the invention, an anastomosis device
generally comprises a tubular member formed of a deformable
material and a graft vessel connected to the tubular member. The
tubular member is transformable upon application of energy to the
tubular member between a non-fluent state and a fluent state in
which the tubular member is radially expandable to sealingly engage
the graft vessel with the target vessel.
[0015] The above is a brief description of some deficiencies in the
prior art and advantages of the present invention. Other features,
advantages, and embodiments of the invention will be apparent to
those skilled in the art from the following description,
accompanying drawings and claims.
BRIEF DESCRIPTION OF THE DRAWINGS
[0016] FIG. 1 is a perspective schematic view of an anastomosis
device of the present invention showing the formable, moldable
tubular member.
[0017] FIG. 1A is a perspective schematic view of an alternative
embodiment of the anastomosis device of FIG. 1 showing a thin sheet
of formable, moldable material.
[0018] FIG. 1B shows a pre-formed tubular member.
[0019] FIG. 2 shows the anastomosis device of FIG. 1 after
positioning the device about an external surface of a free end of
the graft vessel.
[0020] FIG. 3 is an elevated view of the anastomosis device of FIG.
2 with the free end of the graft vessel everted over a portion of
the tubular member.
[0021] FIG. 4 is an elevated view of the anastomosis device and
graft vessel of FIG. 3 and a light-diffusing balloon catheter prior
to insertion of the catheter longitudinally into the graft
vessel.
[0022] FIG. 5 is an elevated view of the anastomosis device of FIG.
4 and balloon catheter inserted into the target vessel through an
incision in the target vessel.
[0023] FIG. 6 is an elevated view of the anastomosis device of FIG.
5 following light irradiation and radial expansion of the
balloon.
[0024] FIG. 7 is an elevated view of the anastomosis device of FIG.
6 after the light-diffusing balloon catheter has been removed from
the graft vessel showing the completed anastomosis.
[0025] FIG. 8 is an elevated view of an alternative embodiment of
an anastomosis device prior to insertion into a graft vessel.
[0026] FIG. 9 shows the anastomosis device of FIG. 8 after
insertion of the device into the graft vessel.
[0027] FIG. 10 is an elevated view of the anastomosis device of
FIG. 8 with a light-diffusing balloon catheter inserted into the
graft vessel and the device.
[0028] FIG. 11 is an elevated view of the anastomosis device, graft
vessel and catheter of FIG. 10 inserted into the target vessel
through an incision in the target vessel.
[0029] FIG. 12 is an elevated view of the anastomosis device of
FIG. 11 following light irradiation and expansion of the
balloon.
[0030] FIG. 13 is an elevated view of the anastomosis device of
FIG. 12 after the light-diffusing balloon catheter has been removed
from the graft vessel showing the completed anastomosis.
DESCRIPTION OF THE INVENTION
[0031] Referring now to the drawings, and first to FIG. 1, an
anastomosis device constructed according to the principles of the
present invention is shown and generally indicated with reference
numeral 8. The anastomosis device (or fastener) 8 is used to
connect a graft vessel 10, such as a thoracic artery or saphenous
vein, to a target coronary vessel 12, such as the left descending
artery, in an anastomosis. The anastomosis device 8 of the present
invention may also be used in connecting various other vessels or
arteries and may be used to connect synthetic vascular grafts to an
artery.
[0032] The fastener 8 comprises a tubular member 20 as shown in
FIG. 1. The tubular member 20 is constructed from a deformable
material that must satisfy various criteria such as moldability,
strength, biocompatability, and light absorption characteristics.
The deformable material may comprise a material that becomes
moldable in vivo by a heat-activated process upon the application,
for example, of radiant energy from an energy source such as a
radio frequency energy source, microwave energy source, ultrasonic
energy source, or light energy source at a predetermined frequency,
wavelength or wavelengths. Alternatively, the deformable material
may become moldable by other conventional heating means, such as by
conductive heating or by convective heating. In addition,
deformable materials that become moldable by a non-thermal
light-activated process without generating heat, such as by a
photochemical process or a photophysical process (i.e.,
photoacoustic or plasma formation), also are contemplated for use
in the present invention.
[0033] The deformable material should become moldable or fluent at
a condition such as temperature that is not significantly injurious
to tissue or surrounding fluids if maintained at that condition for
the amount of time needed to implant and shape the material.
Additionally, if temperature is the germane condition, the material
should become moldable at a temperature above about 40 degrees C.,
since that temperature is greater than a person's body temperature
with hyperthermia or fever (approximately 38 to 40 degrees C.). The
minimum molding temperature prevents the material from
spontaneously softening or melting in response to elevated,
physiologically occurring body temperatures.
[0034] It is also preferred that the deformable material have a
substantially crystalline or semi-crystalline structure so that
when irradiated and transformed into its moldable, fluent state, it
will undergo a rapid transition to a viscous fluid that will flow
readily, yet remain cohesive, when subjected to molding forces. The
materials used in this invention are termed "fluent" when in their
moldable state. The actual viscosity of the fluent material that
allows the material to be molded without significant mechanical
disruption of the tissue depends on the particular tissue and the
method by which the material is molded. In general, it is preferred
that the material be such that once rendered fluent, the material
may be shaped or formed using a physiologically acceptable amount
of force to reduce damage to surrounding tissue during the molding
process. The material must also be structurally sound in its
non-fluent, or solid form, to provide mechanical support and
strength to withstand forces exerted upon the shaped material
during its functional lifetime in vivo at the anastomosis site.
This requirement is important if the material is also bioerodable
after its functional lifespan. The material can include one or more
predefined perforations or apertures (not shown) once transformed
from a delivery configuration to its final, shaped support
configuration. The perforations may allow increased flexibility to
facilitate delivery and reduce tissue erosion during and after
implementation, and increase ingrowth of tissue for anchoring and
encapsulation of the material.
[0035] Where light energy is used as the heat activating medium
(i.e., for a photothermal process), the deformable material should
preferably absorb light within a wavelength range that is not
absorbed significantly (from a clinical perspective) by tissue,
blood, physiological fluids, or water. Wavelengths in the
ultraviolet, visible, and infrared spectrum may be used, for
example, to selectively heat the material to its molding
temperature. Ultraviolet light typically has a wavelength of
between about 100 and 400 nm, visible light has a wavelength
typically in the range of between about 400 and 700 nm, and
infrared light typically has a wavelength of between about 700 and
15,000 nm. Additionally, a chromophore such as a dye or pigment may
be incorporated into the material to selectively absorb light at a
predefined, specific wavelength. As an alternative to compounding
the material with a chromophore, polymers or copolymers that
naturally absorb the wavelength spectrum of the light may be used
and the mechanism of action can be either photothermal or
photochemical as explained above. Preferably, one or more of a wide
variety of therapeutically useful pharmacological agents may be
impregnated into the material, thus providing local drug delivery
to prevent thrombus formation, smooth muscle cell proliferation, or
inflammatory responses. Examples of such drugs include
anti-platelet or anti-thrombus agents (such as Heparin, Hirudin,
tPA, Streptokinase, Urokinase, Persantine, Aspirin, etc.),
anti-inflammatory agents (such as steroidal and non-steroidal
compounds), and anti-proliferative compounds (such as suramin,
monoclonal antibodies for growth factors, and equivalents). In
addition, other potentially useful drugs can be impregnated into
the material to facilitate healing and reduce the incidence of
thrombosis at the anastomosis site, such as immunosuppressant
agents, glycosaminoglycans, collagen inhibitors, and endothelial
cell growth promoters.
[0036] The deformable material is also preferably bioerodable. By
"bioerodable", it is meant that the material will be broken down in
the body and gradually absorbed or eliminated by the body after its
functional lifespan, which in the case of the structural support
application of the present invention preferably is between 3 to 24
months, although shorter or longer periods may be appropriate
depending on the particular application for the fastener 8. Once
the material has been absorbed by the body, the graft will exhibit
similar compliance to that of the native artery. The new tissue
ingrowth forms a natural biological field between the graft vessel
and the target vessel. The new tissue growth connects the graft
vessel to the target vessel so that the fastener is no longer
required.
[0037] Examples of deformable materials which may be used in the
present invention and which typically satisfy the above criteria
include suitable polymers and copolymers, or combinations thereof,
such as polyglycotic/polylactic acid (PGLA), polyhydroxybutylate
valerate (PHBV), polycaprolactone (PCL), polycaprolactone
homopolymers and copolymers, and the like. Many of these materials
(and other similar materials) are fully described in U.S. Pat. No.
5,662,712 to Pathak et al., the entire contents of which are
incorporated herein by reference.
[0038] Polycaprolactone homopolymers and copolymers, for example,
possess adequate strength in their solid form to structurally
support soft tissue lumens. Additionally, once positioned and
molded to a desired shape in a body lumen or about a vessel, the
physical structure of such materials is sufficiently nonvariable,
in the period prior to their bioerosion, to maintain constant
dimensions in their molded state. Polycaprolactones have a
crystalline melting point of approximately 60 degrees C., and can
be deployed in vivo using the method described in detail below.
Additionally, such polymeric materials in their fluent state are
well adapted for mechanical deformation to various degrees and into
various configurations. Polcaprolactone homopolymers and copolymers
can be designed to resorb as soon as three months after
implantation, which may be preferable for the application of the
fastener 8. For example, polycaprolactone copolymerized with lactic
or glycolic acids may resorb over a 3 to 9 month period.
Additionally, other bioabsorbable, deformable materials which have
higher melting temperatures, such as polyglycolides and
polylactides, may be used since these materials have glass
transition temperatures on the order of about 45 degrees C. which
makes them moldable at physiologically acceptable temperatures.
These examples are in no way meant to be limiting, however, and any
deformable, moldable material that satisfies the criteria described
above may be used in the present invention without departing from
the scope of the invention. Any of the methods known in the art of
polymer processing may be used to form the polymeric material into
the tubular shape of FIG. 1 and, if necessary, to compound
chromophores into the material.
[0039] The diameter of the tubular member 20 will vary depending on
the size of the graft vessel about which it is positioned.
Preferably, the inner diameter of the tubular member 20 will
generally be between about 0.5 to 6.0 mm for a coronary
anastomosis. The length of the tubular member 20 can also vary, and
is preferably between 4 and 20 mm in length, for example.
Alternatively, as shown in FIG. 1A, the fastener 8 may comprise a
relatively thin sheet of material 30 that can be conformed about an
external surface of the graft vessel 10 prior to the anastomosis
procedure described below. The sheet 30 may be rolled about the
graft vessel 10. The adhesiveness of the material allows the edges
of the sheet 30 to adhere to one another. If required additional
adhesive may be applied to one or both of the edges of the sheet.
Upon irradiation and subsequent expansion of the material, the
sheet 30 will be caused to unroll to press the graft vessel 10 into
conforming contact with the target vessel 12. Further
alternatively, as shown in FIG. 1B, the fastener 8 may comprise a
pre-shaped tubular member 32 which will at least have a first bend
along its length such that a portion of the tubular member extends
at an angle "R" of between about 30.degree. and 40.degree. from a
longitudinal centerline, the pre-shaped tubular member 32 provides
support for the graft vessel through the anastomosis site after
employment of the device to prevent kinking of the graft
vessel.
[0040] FIGS. 2-7 show an exemplary use of the anastomosis device 8
of the present invention in an open surgical coronary artery bypass
graft procedure via a median or partial sternotomy. The anastomosis
device 8 of this example is preferably formed from a heat-activated
deformable material, although a non-thermal light-activated
deformable material can be used as well without departing from the
scope of the invention. This example is meant to be by illustration
only, and in no way is meant to be limiting. The present invention
can be used in other cardiac surgery procedures such as minimally
invasive direct coronary artery bypass grafting (MIDCAB) on a
beating heart though a small incision (thoracotomy) (about 6-8 cm)
in the left side of the chest wall, in endoscopic minimally
invasive cardiac surgery bypass graft procedures, and in other
vascular procedures to join two vessels together. By way of
example, the left internal thoracic artery is used as the graft
vessel 10. In this example, the left anterior descending artery is
used as the target vessel 12 and contains a build-up of plaque or
narrowing 13. If left untreated, this diseased artery may lead to
insufficient blood flow and eventual angina, ischemia, and possibly
myocardial infarction.
[0041] Conventional coronary bypass graft procedures require that a
source of arterial blood be prepared for subsequent bypass
connection to the diseased artery. An arterial graft can be used to
provide a source of blood flow, or a free vessel graft may be used
and connected at the proximal end to a source of blood flow.
Preferably, the source of blood flow is any one of a number of
existing arteries that are dissected in preparation for the bypass
graft procedure. In many instances, it is preferred to use either
the left or right internal thoracic artery. In multiple bypass
procedures, it may be necessary to use free graft vessels such as
the saphenous vein, gastroepiploic artery in the abdomen, and other
arteries harvested from the patient's body as well as synthetic
graft materials, such as Dacron or Gortex grafts. If a free graft
vessel is used, the upstream end (proximal) of the dissected
vessel, which is the arterial blood source, will be secured to the
aorta to provide the desired bypass blood flow, and the downstream
end (distal) of the dissected vessel will be connected to the
target vessel in a distal anastomosis.
[0042] In order to perform an anastomosis with the fastener 8 of
the present invention, the graft vessel 10 preferably is first
coupled to the fastener 8. Preferably, the graft vessel 10 is
coupled to the fastener 8 by first inserting a free end of the
graft vessel 10 through an opening in the tubular member 20 and
moving the graft vessel 10 longitudinally within the tubular member
20 until the free end of the graft vessel extends a short distance
beyond an end of the tubular member as shown in FIG. 2. Preferably,
the free end of the graft vessel 10 is then everted over an end of
the tubular member 20 as shown in FIG. 3. The natural adhesiveness
of graft vessel 10 or tubular member 20 may be sufficient to secure
the graft vessel 10 to the tubular member 20. If necessary, one or
more sutures can be applied between the graft vessel 10 and the
tubular member 20 to secure the graft vessel 10 to the fastener 8
in an everted configuration. Alternatively, the graft vessel 10 can
be secured to the tubular member 20 with glue, other adhesive
means, by tying one or more sutures circumferentially around the
graft vessel 10, or by any other suitable means.
[0043] Where light energy is used as the heat activating medium, a
suitable light-diffusing balloon catheter device 50 which has the
ability to deliver light energy to luminal surfaces such as blood
vessels is inserted through the lumen of the graft vessel 10 and
fastener 8. An example of a suitable light-diffusing balloon
catheter device 50 is shown in U.S. Pat. No. 5,441,497 to Narciso
et al., the entire contents of which are incorporated by reference
herein, although other suitable light-diffusing balloon catheter
devices may also be used, such as that disclosed in Spears U.S.
Pat. No. 4,773,899, for example. Additionally, a separate light
diffusing catheter (or guidewire) and balloon catheter (not shown)
may be used in conjunction with one another, as disclosed, for
example, in Spears U.S. Pat. No. 5,199,951, the entire contents of
which are incorporated by reference herein. Generally, the
light-diffusing balloon catheter 50 includes a light diffusing
guidewire 60 which is used in conjunction with an inflated balloon
62. The balloon 62 is affixed to the guidewire 60 so that the
balloon 62 overlies the light diffusing member 64 of the guidewire
60. The wall of the balloon 62 is transparent at the wavelength of
light being delivered to (or received from) the surrounding tissue.
At least one optical fiber 66 delivers light from an external light
source (not shown) to the light diffusing member 64. The light
diffusing member 64 within balloon 62 is selected for optimum
transmission of light with maximum light scattering.
[0044] The graft vessel 10 is inserted into the target vessel 12
through an incision (opening) 16 in a wall of the target vessel 12.
The fastener 8 is preferably positioned in the target vessel 12
such that at least an end portion of the tubular member 20 extends
generally coaxial with the target vessel 12 (FIG. 5). With the
fastener 8 securely positioned in the target vessel 12, light
energy at a given wavelength or wavelengths is supplied to the
light diffusing member 64 from the energy source via optical fiber
66 to irradiate, or illuminate, the tubular member 20 with light at
a wavelength or wavelengths at which the deformable material
readily absorbs. Upon absorption of the light energy, the
deformable material forming tubular member 20 is transformed into
its moldable state. Alternatively, where heat energy is used as the
heat activating medium, the deformable material can be made fluent
by use of a suitable thermal balloon catheter (not shown) in lieu
of the light-diffusing balloon catheter 50, or by any other
conductive or convective heating means as would be obvious to one
of ordinary skill in the art, such as by providing a heated saline
irrigation flush. Inflation of the balloon 62 causes the tubular
member 20 to radially expand outwardly, thereby pressing the graft
vessel 10 into conforming engagement with an inner wall of target
vessel 12 (FIG. 6). Alternatively, where the deformable material
comprises a rolled sheet 30 such as in FIG. 1A which can be
reconfigured prior to molding, the material is reconfigured using
the balloon and then irradiated to transform it into its moldable
state to mold it into conformance with the everted graft vessel 10
and target vessel 12. By discontinuing the supply of light energy
from the energy source, the deformable material will become
non-fluent and remain in its molded configuration. The balloon 62
is then deflated and the catheter device 50 withdrawn from the
graft vessel 10 (FIG. 7).
[0045] The engagement of the graft vessel 10 via tubular member 20
with the inner wall of the target vessel 12 prevents substantial
longitudinal movement of the tubular member 20 within the target
vessel. The tubular member 20 in its molded configuration will
apply a gentle uniform, circumferential pressure against the
everted graft vessel 10 and the inner wall of the target vessel 12.
An intima-to-intima anastomosis results. The flexibility of the
tubular member 20 permits the fastener device 8 to be substantially
compliant with the target vessel 12 and the graft vessel 10 to
reduce thrombosis formation. Additionally, the tubular member 20 is
preferably bioerodable, so that after its functional lifespan
(i.e., 3 to24 months), it will degrade and leave remaining a
natural patent, sealed, compliant anastomosis.
[0046] If required, cardiac stabilization such as described in
co-pending provisional patent application for Compositions,
Apparatus and Methods For Facilitating Surgical Procedures, filed
Aug. 8, 1997 and invented by Francis G. Duhaylongsod, M.D, may be
used during the procedure. Other pharmacological or mechanical
methods may also be used.
[0047] In an alternative embodiment of the present invention, a
different fastener device is disclosed for sealingly joining a
graft vessel to a target vessel at an anastomosis site. The
fastener (not shown) of this embodiment comprises a coating of a
fluent, curable material, such as a liquid or viscous gel, which is
applied to an external surface of a free end portion of the graft
vessel 10. Examples of suitable curable materials include, but are
not limited to, light-curable materials such as the chemical class
of biocompatible compounds including acrylate polymers which can be
cured when exposed to ultraviolet light, and acrylate urethane
polymers which can be cured when exposed to ultraviolet light
and/or visible light of sufficient intensity. These materials also
can be combined with a dye that absorbs light at a very specific
wavelength so that light energy can be used to selectively and
rapidly cure the material and not heat the surrounding tissue.
[0048] Other suitable light-curable materials may include
bioerodable hydrogens which can be photopolymerized (or gelled) in
vivo by a brief exposure to long wavelength ultraviolet light, such
as polyethylene-glycol (PEG) based hydrogels as fully disclosed in
U.S. Pat. No. 5,410,016 to Hubbell et al. Several biocompatible,
photopolymerizable macromer hydrogels are disclosed in U.S. Pat.
No. 5,410,016 (see, for example, Table I therein) which are
suitable as tissue supports by forming shaped articles within the
body upon the application of light energy at a specific wavelength.
These macromers, for example, can be composed of degradable
co-monomers such as glycolides, lactides, and caprolactones of
various molecular weights and compositions. These materials are
given by way of example only, and in no way are meant to limit the
invention to the specific materials disclosed. Any suitable
light-curable material having the requisite strength,
biocompatability and moldability criteria may be used without
departing from the scope of the present invention. In addition,
heat-curable materials can be used in a similar fashion with the
method of heating chosen from the list set forth above for
deformable materials, such as convective or conductive heating.
[0049] As in the previous example, the curable material can be
impregnated with one or more anti-platelet or anti-thrombus agents,
anti-inflammatory agents, and anti-proliferative compounds. In
addition, other potentially useful drugs can be impregnated into
the material to facilitate healing and reduce the incidence of
thrombosis at the anastomosis site, such as immunosuppressant
agents, glycosaminoglycans, collagen inhibitors, and endothelial
cell growth promoters. Preferably, where light-curable materials
are used, wavelengths in the ultraviolet, visible, and infrared
light spectrum may be used, for example, to transform the curable
material into its cured state, since light energy within these
wavelengths is not significantly injurious to surrounding tissues.
Additionally, a chromophore such as a dye or pigment may be
incorporated into the material to selectively absorb light at a
predefined, specific wavelength or wavelengths.
[0050] The method of using the fastener of this embodiment is
similar in many respects to that shown for use of the tubular
member 20 of FIGS. 1-7, with the principal difference being that
the energy supply and balloon expanding steps are typically
reversed. In this alternative embodiment, after the coating of
curable material is applied to an external surface of the free end
portion of the graft vessel 10, the free end portion of the graft
vessel 10 is everted. The curable material typically has a natural
adherent property in which case the free end portion of the graft
vessel 10 in its everted configuration will be adhered and secured
to the coating material. If necessary, one or more sutures may be
required to retain the free end of the graft vessel 10 in an
everted configuration. Subsequently, where a light-curable coating
material is used, a light-diffusing balloon catheter 50 such as
shown in FIG. 4 preferably is inserted into the graft vessel 10.
Alternatively, as above, a separate light diffusing catheter (or
guidewire) and balloon catheter (not shown) may be used in
conjunction with one another.
[0051] At least a portion of the everted free end portion of the
graft vessel 10 is then positioned in the target vessel 12 through
an incision 16 in the target vessel 12. The balloon 62 of
light-diffusing balloon catheter 50 is then inflated to radially
expand at least the free end portion of the graft vessel 10 into
conforming engagement with an inner wall of the target vessel 12.
Once expanded, curing is achieved by irradiating, or illuminating,
the free end portion of the graft vessel 10 with light energy at a
predetermined wavelength or wavelengths supplied by an energy
source coupled to the light diffusing member 64 of light-diffusing
balloon catheter 50. The light energy preferably has a wavelength
and intensity which does not have a significant adverse effect on
the surrounding tissue, such as light within the ultraviolet,
infrared, or visible light spectrum. The intensity of the light
energy is sufficient to transform the curable material into its
cured, non-fluent state to complete the anastomosis. The balloon 62
can then be deflated and the light-diffusing balloon catheter 50
removed from the graft vessel 10. Again, an intima-to-intima
anastomosis results which reduces the possibility of thrombosis
formation at the anastomosis site. Alternatively, where a
heat-curable coating material is used, the curable material can be
cured by use of a suitable thermal balloon catheter (not shown) in
lieu of the light-diffusing balloon catheter 50, or by any other
conductive or convective heating means as would be obvious to one
of ordinary skill in the art, such as by providing a heated saline
irrigation flush.
[0052] In alternative embodiments of the invention, the anastomosis
fastener can comprise either a tubular member formed of a
deformable material or a coating of a curable material that is
applied to the internal wall of a free end portion of graft vessel
10. In the case of the embodiment shown in FIGS. 8-13, the fastener
108 comprises a tubular member 120 having a diameter sized to
permit the tubular member 120 to be inserted longitudinally into
the graft vessel 10, as shown in FIGS. 8-9. As shown in FIG. 10,
where a light-activated deformable material is used, a
light-diffusing balloon catheter 50 can then be inserted into the
graft vessel 10 and the tubular member 120 and positioned such that
the balloon (not shown) of the light-diffusing balloon catheter 50
is adjacent an internal surface of tubular member 120. If
necessary, the balloon can be partially inflated to secure the
tubular member 120 in place prior to inserting the graft vessel 10
into the target vessel 12. With the tubular member 120 securely in
place within the free end portion of the graft vessel 10, the graft
vessel 10 is then inserted into the target vessel 12 such that at
least the free end portion of the graft vessel 10 extends generally
coaxial with the target vessel 12, as shown in FIGS. 11-12.
[0053] With the graft vessel 10 securely positioned in the target
vessel 12, light at a given wavelength or wavelengths is supplied
by the light-diffusing balloon catheter 50 to irradiate, or
illuminate, the tubular member 120 with light at a wavelength or
wavelengths at which the material readily absorbs. Upon absorption
of the light, the material forming tubular member 120 is irradiated
to transform it into its fluent, moldable state. Further inflation
of the balloon causes the moldable tubular member 120 to radially
expand outwardly, thereby pressing the graft vessel 10 into
conforming engagement with an inner wall of target vessel 12. By
discontinuing the supply of light energy from the light source, the
formable material will become non-fluent and remain in its molded
configuration. The balloon is then deflated and the catheter device
50 withdrawn from the graft vessel 10, as shown in FIG. 13. An
intima-to-adventitia anastomosis results.
[0054] Alternatively, a coating of a curable material can be
applied to an internal wall of the free end portion of the graft
vessel 10. In this particular embodiment, the balloon 62 will be
expanded fully prior to applying light energy, or heat, to the
coating material. Where a light-curable coating material is used,
with the graft vessel in conforming engagement with the target
vessel 12, curing is achieved by irradiating, or illuminating, the
free end portion of the graft vessel 10 with light energy at a
predetermined wavelength or wavelengths supplied by an energy
source coupled to the light diffusing member of the light-diffusing
balloon catheter 50. The intensity of the light energy is
sufficient to transform the curable material into its cured,
non-fluent state to complete the anastomosis. The balloon can then
be deflated and the light-diffusing balloon catheter 50 removed
from the graft vessel 10.
[0055] The engagement of the graft vessel 10 via tubular member 120
(or the cured, nonfluent coating of curable material) with the
inner wall of the target vessel 12 prevents substantial
longitudinal movement of the graft vessel 10 within the target
vessel 12. The tubular member 120 (or the cured, non-fluent
coating) in its molded configuration will apply a gentle uniform,
circumferential pressure against the graft vessel 10 and the inner
wall of the target vessel 12. The flexibility of the tubular member
120 (or the cured, non-fluent coating) permits the fastener device
108 to be substantially compliant with the target vessel 12 and the
graft vessel 10 to reduce thrombosis formation. Additionally, the
tubular member 120 (or the cured, non-fluent coating) is preferably
bioerodable, so that after its functional lifespan (i.e., 3 to 24
months), it will degrade and leave remaining a natural patent,
sealed anastomosis. Although the embodiments of FIGS. 8-13 result
in an intima-to-adventitia anastomosis as opposed to an
intima-to-intima anastomosis as in the above embodiment of FIGS.
1-7, the anastomosis of these embodiments results in a larger
target vessel inner diameter over the previous embodiments, thus
increasing the blood flow area, rather than reducing the diameter
of the blood flow passage.
[0056] It should be understood that while the above is a complete
description of the preferred embodiments of the invention, various
alternatives, modifications and equivalents may be used. Therefore,
the above description should not be taken as limiting the scope of
the invention which is defined by the following claims.
[0057] All references cited herein are incorporated by
reference.
* * * * *