Internal graft prosthesis and delivery system

A resilient tubular graft is delivered into place within a body passage by elongating the graft to reduce its diameter and then directing the graft to the desired position while in the elongated condition. The graft is carried into position by a pair of elongate members mounted for longitudinal movement relative to one other. Flexible lines secure opposite ends of the graft to the respective elongate members whereby relative longitudinal movement of the members functions to elongate the graft and reduce its diameter. The lines extend around the graft to impart radial compression thereto simultaneously with elongation of the graft. Upon placement of the graft at the desired location within a body passage, the lines are released to permit the graft to expand into engagement with the passage. Barbs on the graft provide for secure engagement of the graft with a body passage.

BACKGROUND OF THE INVENTION 
The present invention relates to a prosthetic graft and a method and 
apparatus for placing the graft within a body passage. In its more 
particular aspects, the invention is concerned with a resilient tubular 
graft which may be reduced in diameter for delivery and then expanded into 
place. The invention is especially concerned with such a graft which may 
be deployed within the thoracic aorta, the abdominal aorta, or the femoral 
artery, via a groin incision. 
The prior art teaches expansible tubular grafts for use in body passages. 
For example, U.S. Pat. No. 4,655,771 discloses such a graft which may be 
elongated for delivery and then expanded into place. With the device of 
that patent, the ends of the graft are held within tubular fixtures which 
are used to impart elongation to the graft to reduce its diameter during 
delivery. Once the graft is in place, these fixtures are removed to 
release the graft for expansion. The employment of the fixtures 
necessarily adds to the bulk and complexity of the mechanism and limits 
its use. Another example of an expansible intraluminal graft is found in 
U.S. Pat. No. 4,776,337. The device of that patent is fabricated of a 
malleable material which is delivered in a reduced diameter condition and, 
once in place, expanded by an angioplasty balloon to dilate and expand the 
lumen of a blood vessel. 
The prior art also teaches expansible devices for vessel dilation embodying 
braided cylinders of an adjustable axial length structured such that a 
reduction in the length increases the radial size of the device. U.S. Pat. 
No. 4,572,186 shows such a device. 
It is also known to provide sheaths which may be placed in vessels to 
facilitate the passage of other instruments or catheters therethrough. 
U.S. Pat. Nos. 4,493,711 and 4,798,193 teach such devices. 
SUMMARY OF THE INVENTION 
The graft of the present invention is resilient and of a tubular 
configuration adapted to assume a foreshortened enlarged diameter 
condition upon relaxation and, upon being elongated, assume a reduced 
diameter condition. The mechanism for delivery of the graft comprises an 
elongate placement means which extends longitudinally of the graft to 
carry the graft through a body passage and facilitate its placement. 
Flexible lines secure opposite ends of the graft to the elongate placement 
means. The lines are movable to selectively elongate the graft for 
delivery, or expand the graft for placement. A retractable sheath may be 
provided to shield the mechanism and graft during the delivery process. 
The method of the invention comprises the steps of securing opposite ends 
of the graft to a placement member with flexible lines, moving the lines 
to elongate the graft, passing the placement member through a body passage 
with the graft carried thereby in a reduced diameter elongated condition, 
and positioning the graft and releasing the lines at the desired location. 
In the preferred embodiment the lines are also extended around the graft 
to subject it to radial compression simultaneously with its elongation. 
A principal object of the invention is to provide an improved graft and 
system and method for its delivery and placement which enables the graft 
to be delivered through elongate body passages. 
Another object of the invention is to provide an improved expansible 
tubular graft which may be fabricated with fluid permeable, or 
impermeable, walls. 
Still another object is to provide such a graft which is biocompatible with 
the body and has means to securely anchor it in place. 
A further object is to provide such a graft which may be securely placed 
with a main artery without blocking branch arteries, even where there is 
not a substantial length of healthy artery between the aneurysm being 
treated and the branch arteries. 
Yet another more general object of the invention is to provide an improved 
apparatus and method for intraluminal delivery of a graft to a select 
remote area within a body passage, without need to surgically access the 
area. 
Yet a further object of the invention is to provide an apparatus and method 
for the intraluminal placement of a graft within a body passage which may 
be carefully controlled to provide precise placement of the graft and 
repeatedly adjusted. 
Still another object related to the latter object is to provide such an 
apparatus and method wherein the graft can be precisely located and fully 
expanded before its release from the delivery system. 
These and other objects will become more apparent from the following 
detailed description and accompanying drawings.

DESCRIPTION OF THE PREFERRED EMBODIMENT 
FIG. 1 shows the graft and delivery system in exploded perspective, with 
the graft designated by the letter G and the delivery system designated in 
its entirety by letter S. The graft, as may be seen in FIG. 2, is of an 
open-ended tubular configuration and comprises filaments F.sub.1 and 
F.sub.2 extending helically therearound. The filaments F.sub.1 and F.sub.2 
extend around the graft in opposite directions and cross at intersections 
I. The filaments are fabricated of a resilient material, such as 
polyester, titanium or stainless steel. The filaments cross over each 
other at intersections I. As a result of the resiliency of the filaments, 
the graft normally assumes a foreshortened enlarged diameter upon 
relaxation and, upon being elongated, assumes a reduced diameter condition 
(see FIG. 3). In a typical embodiment for use in treating a dissecting 
aneurysm in the aorta, the graft might have the following dimensions: 
______________________________________ 
ELEMENT DIMENSION 
______________________________________ 
Filament diameter .010 inches 
Graft diameter in the relaxed condition 
1.0-1.25 inches 
Graft length in the relaxed condition 
3.0-6.0 inches 
______________________________________ 
In a typical application, the graft is elongated to double its length for 
delivery, with the result that the outside diameter of the graft is 
reduced by substantially more than one-half. 
The components of the delivery system may best be seen from FIG. 4 and 
comprise: 
1. An outer tube 10 having an outer hub 12 fixed to its proximal end and a 
lateral opening 14 adjacent its distal end; 
2. A middle tube 16 proportioned for slidable extension through the outer 
tube 10, said middle tube having a middle hub 18 fixed to its proximal end 
and a lateral opening 20 adjacent its distal end; 
3. A flexible distal retainer rod 22 proportioned for slidable extension 
through the middle tube 16, said rod having a rod hub 24 fixed to its 
proximal end; 
4. A closed loop flexible line 26 fixed at one end to the hub 24 and closed 
at its distal end 28; 
5. A proximal suture loop retainer wire 30 proportioned for slidable 
extension through an opening 32 formed in one side of the hub 24 and 
through a passage 34 formed in the middle hub 18, said retainer wire 
having a retainer hub 36 fixed to its proximal end; and, 
6. A looped flexible line 38 fixed at its proximal end to the hub 36 and 
closed at its distal end 40. 
FIG. 1 shows the delivery system in the assembled condition, with the outer 
hub, middle hub and rod hub exploded relative to one another for purposes 
of illustration. The middle tube 16 extends slidably through the outer 
tube 10. The retainer rod 22, together with the looped flexible line 26 
extends through the middle tube 16 and the closed distal end 28 of the 
line 26 extends through the opening 20 and around the graft G. The wire 
30, together with the looped flexible line 38, extends through the opening 
32 in the hub 24 and thence through the opening 34 in the hub 18 and 
through the hub 12 and the outer tube 10. From the latter, it will be 
appreciated that there is sufficient space between the outer tube 10 and 
the middle tube 16 to accommodate free passage of the wire 30 and looped 
line 38 therethrough. The looped flexible line 38 exits the tube 10 
through the opening 14 and extends around the graft G. 
FIG. 2 shows in detail the manner in which the looped lines 26 and 38 
extend around the graft G. As there shown, it will be seen that the looped 
line 38 is threaded into and out of the graft around its proximal end and 
exits from the graft to a closed end 40 engaged around the retainer wire 
30. The looped flexible line 26 is fed into and out of the graft G around 
its distal end and exits therefrom, with the end 28 engaged around the rod 
22. Thus, with the rod 22 and wire 30 in place as shown in FIG. 2, the 
looped ends of the lines 26 and 38 are secured around the distal and 
proximal ends, respectively, of the graft G. In this condition, movement 
of the hub 12 into mated engagement with the middle hub 18 functions to 
elongate the graft G and cinch the ends of the looped lines around the 
graft, as shown in FIG. 3. Such elongation and cinching reduces the 
diameter of the graft by substantially more than one-half. 
From FIG. 4 it will be seen that the hubs are configured to mate one within 
the other in a nested condition. Hub 12 has a recess 42 proportioned to 
receive a collar 44 formed on one end of the hub 18. A collar 46 formed on 
the other end of the hub 18 is proportioned for mating engagement within a 
recess 46 formed in the hub 24. The retainer hub 36 is formed with screw 
threads 48 formed for threaded engagement with a threaded opening 50 in 
the hub 18. When the hubs are fully nested, the opening 32 is aligned with 
the opening 50 and the hub 36 is passed through the opening 32 into 
threaded engagement with the opening 50. 
FIG. 5 shows the delivery system fully assembled, with the hubs nested 
together and the graft G in the fully elongated reduced diameter 
condition. As there shown, the graft is in the process of being introduced 
into the femoral artery 52 through a partially split sheath 54. The sheath 
has a length equal to or slightly greater than that of the delivery system 
and, during the delivery process, fully encloses that part of the system 
disposed within the artery. Once fully in place at the site where it is 
desired to locate the graft, the sheath is partially withdrawn, as shown 
in FIG. 5, to expose the graft. 
FIGS. 6 and 7 show the detailed construction of the sheath. The sheath is 
preferably made of a flexible material having a relatively low coefficient 
of friction, such as polyethylene or TEFLON. The proximal end of the 
sheath, designated 56, is of an open funnel-shaped configuration with a 
slit 58 extending over its length. The distal end of the sheath, 
designated 60, is of a closed conical configuration with a slit 62 
extending thereacross to permit the delivery system to be passed 
therethrough, as shown in FIG. 5. 
The graft G may be either fluid permeable or impermeable, or a combination 
of permeable and impermeable portions, depending upon the area of its 
intended use. Permeability naturally results from the spacing of the 
filaments F.sub.2. Impermeability may be provided by coating the graft 
with an elastomer, such as silicone. 
OPERATION 
The operation of the graft and delivery system may be seen from FIGS. 8, 9 
and 10. In FIG. 8, the graft is shown in the elongated contracted 
condition, with the sheath retracted prior to expansion and release of the 
graft from the delivery system. Expansion is provided by moving the hub 12 
forwardly away from the hub 18 which, in turn, moves the distal end of the 
outer tube 10 toward the distal end of the middle tube 16 (See FIG. 9) and 
permits the graft to foreshorten and expand into engagement with the 
artery. If the graft is not positioned at the precise location desired, it 
may be re-elongated by moving the hub 12 into engagement with the hub 18 
and repositioned. Once the graft is expanded at the precise location 
desired, it is released from the delivery system by first withdrawing the 
wire 30 and the flexible line 38 and then withdrawing the rod 22 and the 
flexible line 26. Withdrawal of the wire 30 and the rod 22 releases the 
looped distal ends 40 and 28 of the lines. Once the lines are so released, 
proximal pulling of the lines (See FIG. 10) pulls the lines from the graft 
and out of the delivery system. The remaining components of the system can 
then be fully withdrawn from the artery through the groin incision. The 
sheath 54 may be left in place to facilitate such withdrawal. 
The graft may also be provided with barbs B for engagement with the body 
passage within which the graft is used. Such barbs, as shown in FIG. 2, 
may comprise folded-over titanium staples passed through the material of 
the graft. 
FIGS. 11, 12, 13 and 14 show different applications of the graft. In FIG. 
11, an impermeable coated form of the graft G is shown within an artery 
A.sub.1 at the site of an aneurysm which is shielded by the graft. The 
coating on the graft is designated by the letter C. FIG. 12 shows an 
artery A.sub.2 having a dissecting aneurysm 64. FIG. 13 shows the same 
artery A.sub.2 with its lumen forced open by a permeable form of the 
graft, designated G.sub.1. In this application, the permeable character of 
the graft permits blood to flow from the artery A.sub.2 into the branches 
A.sub.3. The arrow lines in FIGS. 12 and 13 depict the direction of the 
flow of blood. As shown in FIG. 13, the graft G, compresses the aneurysm 
and permits free flow through the artery. FIG. 14 shows an artery A.sub.4 
having an aneurysm 66 without a substantial length of healthy artery 
between the aneurysm and renal arteries 68. As there shown, a graft 
G.sub.2 having an impermeable portion 70 and a permeable portion 72 is 
used. The impermeable portion 70 is positioned over the aneurysm 66 and 
adjacent healthy tissue and the permeable portion 72 is placed over the 
renal arteries 68 and adjacent healthy tissue of the artery A.sub.4. Thus, 
the graft bridges the aneurysm and the renal arteries, allowing flow 
through all arteries and providing for positive graft fixation. 
FIG. 15 shows the manner in which the graft may be inserted into the 
femoral artery through a groin incision and directed to treat a dissecting 
thoracic aneurysm, such as that shown in FIGS. 12 and 13, or an abdominal 
aortic aneurysm. Dashed lines 74 depict where the graft would be 
positioned for treating a dissecting thoracic aneurysm. Dashed lines 76 
depict where the graft would be positioned for treating an abdominal 
aortic aneurysm. Because of the side branches at the thoracic aneurysm, 
the permeable embodiment of FIG. 13 would be used at that location. The 
abdominal aortic aneurysm would be treated with the impermeable graft 
embodiment of FIG. 11. 
CONCLUSION 
From the foregoing description, it is believed apparent that the present 
invention enables the attainment of the objects initially set forth 
herein. In particular, a graft and delivery system is provided which may 
be delivered to remote locations to treat various types of aneurysms. It 
should be understood, however, that the invention is not intended to be 
limited to the illustrated embodiment, but rather is defined by the 
accompanying claims.