Apparatus for forming custom length grafts after endoluminal insertion

A device for endoluminally cutting a graft is disclosed. The device includes an elongated catheter having an actuator at its proximal end and a cutting element remote from its proximal end. The actuator causes the cutting element to sever the graft endoluminally. The cutting element effects a cut through the wall of the graft to cut the graft, endoluminally, to a desired length. The cutting element includes a portion shaped so that the catheter can be positioned relative to the graft with the graft in close proximity to the cutting element.

FIELD OF THE INVENTION 
This invention relates to a method for endoluminally deploying a graft in a 
body passageway, for example, for the purpose of isolating an abdominal 
aortic aneurysm. 
BACKGROUND OF THE INVENTION 
Marin et al. U.S. Pat. No. 5,507,769 describes a method and apparatus for 
endoluminally deploying a graft across an aortic aneurysm and associated 
common iliac aneurysms. In that patent, separate grafts are advanced 
through a patient's femoral and iliac arteries and aligned in a common 
region in the aorta above the aneurysm. Cephalic stents are deployed in 
that region to effectively create a bifurcated graft with the individual 
legs of the graft extending into the patient's arteries. Suitable stents 
are likewise deployed in these legs caudal of the aneurysm, thus isolating 
the aneurysm. 
Marin et al. U.S. Pat. No. 5,507,769 in its entirety is hereby incorporated 
by reference. 
The iliac arteries each include a branch known as the internal iliac 
artery. It is necessary that the grafts terminate cephalic of the internal 
iliac arteries so as not to block blood flow through these arteries. 
Assuming that the upper arteries may vary in length, the appropriate 
length of an individual graft will also need to vary considerably from 
patient to patient. This means that the surgeon must anticipate the length 
of the graft. If he/she is mistaken, the graft must be removed and a new 
graft inserted so as not to block important branch arteries, which is 
obviously undesirable. Moreover, the manufacturer must make different 
length grafts and the hospital must keep an inventory of all of the 
different lengths that may ultimately be needed. 
OBJECT OF THE INVENTION 
The object of the invention is to alleviate the foregoing problems. 
More specifically, it is an object of the invention to provide a method for 
endoluminally placing a graft of a standard length in a body passageway 
wherein the final length of the graft may be formed endoluminally. 
SUMMARY OF THE INVENTION 
In accordance with the invention, a graft is inserted into a passageway 
such as a patient's artery. After the distal end of the graft is tacked to 
the passageway, a special intraluminal cutting device is threaded along 
the graft and actuated at the appropriate position so that the graft can 
be cut to the proper size. 
The cutting device may be contained within the delivery system along with 
the graft such that actuation of a cutting element may take place entirely 
within the catheter system. This arrangement will permit this procedure to 
be performed percutaneously eliminating the need to directly expose the 
artery. 
In a preferred embodiment, the cutting device may include a tube through 
which a contrast solution can be introduced into an artery so that the 
position of the cutting device can be precisely determined by an 
arteriogram. For example, in the case of an abdominal aneurysm, the 
cutting device will be positioned so that the proximal end of the graft 
will be severed at a point which is cephalad of the internal iliac artery.

DETAILED DESCRIPTION 
The present invention was developed as an improvement over the endoluminal 
grafting procedure disclosed in U.S. Pat. No. 5,507,769 but the invention 
is not limited to that procedure. Just as in the case of U.S. Pat. No. 
5,507,769, the invention may be used to bypass pathological defects other 
than aneurysms and vascular occlusions, for example malignancies. The 
invention is not limited to arteries or even the vascular system, and will 
have utility in other body passageways, such as the trachea, esophagus or 
colon, or wherever grafts have or may have utility. In general, the 
invention will have utility with any passageway (whether or not 
bifurcated) so long as the ability to customize the length of the graft in 
situ is beneficial. Nevertheless, despite the broad application of the 
basic principles of the invention, the preferred embodiment is described 
below in connection with the placement of a bifurcated graft for the 
purpose of bypassing an aortic aneurysm encompassing the junction of the 
aorta and the iliac arteries. 
In describing the preferred embodiments of the invention, a balloon 
deployed stent (such as the Palmaz stent) is described as the device for 
securing the graft in the vasculature. The invention, however, is not 
limited to any particular type of stent and other stents (including but 
not limited to self-expanding stents such as the Walsten stent and stents 
made of shape memory alloys, e.g. Nitinol) can also be used. In place of a 
balloon, mechanical deployment means may be used. 
In the following description and claims, the terms used have the 
definitions set forth in U.S. Pat. No. 5,507,769. Specifically, the terms 
"distal" and "proximal" refer to the device itself and not to the 
vasculature. The vasculature is referred to with respect to the cephalic 
(closer to head) and caudal (further from head) directions. The term 
"above" refers to the regions cephalic of the aneurysm (for example) and 
"below" refers to the region of the vasculature caudal of the aneurysm. 
In the illustrated embodiments, the grafts are cut to the desired length by 
means of a sharp cutting edge, however, it is conceivable that other types 
of devices may be used (for example, heat or light responsive devices) to 
sever the graft. Accordingly, as used herein, the term "cutting" is 
intended to encompass any procedure for forming a graft to a predetermined 
length. 
FIG. 1 is a diagram of the arterial system in the vicinity of the abdominal 
aorta. The aorta, left and right common iliac arteries, left and right 
renal arteries, and left and right internal iliac arteries are labelled 
accordingly on the drawing. An aortic aneurysm 40 is shown occupying a 
large area at the junction of the aorta and the iliac arteries. 
To bypass the aneurysm 40 it is necessary that the graft extend from a 
position caudal of the renal arteries to positions cephalic of the 
internal iliac arteries so that blood flow through the latter arteries is 
not interfered with. In practice it is difficult to estimate accurately 
the proper length of the graft to achieve this objective since the 
aneurysm may change shape and configuration once pressure has been 
eliminated from the lumen. 
In accordance with the invention, a graft of a defined length, which is 
expected to be longer than required, is used for each leg. For example, 
each of the grafts may be approximately 40 cm long but otherwise identical 
in construction to known grafts as described in U.S. Pat. No. 5,507,769. 
In the illustrated embodiment, the femoral arteries are entered within the 
thigh by an arterial incision where the artery is exposed where it comes 
close to the surface of the skin. A guide wire and catheter are then 
introduced into the patient's artery and snaked into position above the 
aneurysm 40. After the left and right guide wires are in place, the grafts 
44L and 44R are introduced into the guide catheter and snaked through the 
aneurysm until their distal ends are properly positioned above the 
aneurysm. Stents are then deployed to attach the distal ends of the grafts 
to the aorta near the renal arteries. 
The process and apparatus for positioning the distal ends of the grafts and 
deploying the cephalic stents is fully described in U.S. Pat. No. 
5,507,769 and, therefore, is not repeated herein. 
The length of the grafts is such that the proximal ends extend from the 
arterial incision through which the grafts were introduced into the 
patient's vasculature. A special intraluminal cutting device is provided 
which may be positioned on the graft extending from the incision. The 
cutting device is then advanced through the artery over the graft cephalad 
to a position where it can be actuated to cut the graft to the desired 
length. The position of the cutting device within the artery is determined 
by means of an arteriogram. The contrast material for the arteriogram may 
be injected through a suitable tube attached to the intraliminal cutting 
device which is accessible to medical personnel. When the arteriogram 
indicates that the cutting device is in a proper position cephalic of the 
internal iliac artery, the device is actuated to sever the graft. The 
proximal end of the graft is then secured to the arterial wall with 
another stent after the severed portion of the graft and the cutting 
device have been removed. 
In the illustrated example, the same process may be repeated on the 
opposite side to complete the bifurcated configuration and construct a 
graft of appropriate length. The invention enables a graft to be formed in 
which one limb is longer than the other if this is dictated by the 
arterial anatomy. 
FIG. 2 helps to illustrate the way in which various different types of 
graft cutting devices can be used in accordance with the invention. 
Continuing with the example of U.S. Pat. No. 5,507,769, FIG. 2 shows the 
right femoral artery after the graft 44R has been inserted and the 
cephalic stent deployed to hold the graft in place. The graft 44R extends 
from an incision H through which the graft was previously inserted as 
explained in U.S. Pat. No. 5,507,769. The invention provides a way for 
cutting graft 44R just cephalic of the right iliac artery so that the 
caudal stent (not shown) can be deployed in the vicinity of attachment 
point J. 
In this embodiment, and as shown more clearly in FIG. 3, the cutting device 
includes a catheter 50 and an elongated wire 52, in the shape of a snare, 
which terminates in proximal knobs 54 and 56 and includes a distal cutting 
loop 58 extending from the distal end of the catheter 50. Attached to the 
catheter 50 is a small tube 60 having apertures 62 at its distal end so 
that a contrast solution can be injected into the artery. 
The ends of the snare 52 extend through a hemostatic valve 64 which 
includes a port 66 through which contrast solution can be introduced into 
the tube 60. 
The loop 58 includes a cutting surface 68 (FIG. 4) so that when the snare 
52 is pulled tight, the cutting edge 68 will sever the graft 44R. As shown 
in FIG. 3, the loop 58 extends at an angle from the catheter 50 at its 
distal end. This angle is selected primarily with the view of enhancing 
cutting efficiency and minimizing the profile. An angle of 45.degree. 
appears optimal. 
The device shown in FIGS. 1-6 is used as follows. 
With the graft 44R extending from the incision H in the femoral artery, the 
proximal end of the graft is placed through the loop 58. By pulling on one 
of the knobs 54, 56 and pushing on the other, the sharp cutting edge 68 
can be positioned within the catheter 50 (shown in FIG. 3). Using the 
graft 44R in the fashion of a guide wire, the surgeon then pushes the 
catheter 50 through the artery with the object of positioning the cutting 
device cephalic of the right iliac artery. Contrast solution is introduced 
through port 66, exiting from the holes 62 in tube 60. When the distal end 
of catheter 50 is positioned cephalic of the right iliac artery, the knobs 
54, 56 are manipulated to bring the sharp cutting edge around the graft 
44R. The surgeon then grasps the knobs 54 and 56, while maintaining the 
graft and catheter 50 are stationery, and pulls the loop 58 into the 
catheter, as shown in FIG. 6. This action, which is analogous to the 
action of a surgical snare, causes the cutting edge 68 in the loop to 
sever the graft. 
The severed portion of the graft 44R and the catheter 50 are then removed 
leaving only the guidewire (not shown) extending through the graft. A 
stent loaded catheter (which may be conventional) is then passed over the 
guidewire into the graft. When the stent is properly positioned at the 
caudal end of the graft (as indicated by the radiopaque markers), the 
stent is deployed and the catheter and guidewire removed. Obviously, the 
type of stent and its method of deployment form no part of this invention. 
In the embodiment of FIGS. 7 and 8, the cutting device comprises two 
separate wire loops 70 and 72 which are controllable from a position 
external of the patient. The loop 70 includes a sharp outer cutting edge 
70A while the loop 72 includes a sharp inner cutting edge 72A. The graft 
44R passes between the two cutting edges 70A and 72A as shown in FIG. 8. 
The operation of this device is similar to the operation of the device 
shown in FIGS. 2-6 insofar as positioning the cutting surfaces is 
concerned. When the devices is properly positioned, the surgeon pulls on 
the loops 70 and 72 closing the gap between the cutting edges 70A and 72A 
to sever the graft. 
The cutting device shown in FIGS. 9 and 10 comprises a metallic cylinder 
74, which is movable with respect to the catheter 50, and a wire loop 76. 
The cylinder 74 includes a cutting edge 74A at its distal end. Because of 
the sharp cutting edge 74A, the cylinder 74 is retracted into catheter 50 
as the catheter is moved to the cutting position. When the catheter 50 is 
properly positioned, the catheter 50 is pulled proximally to the position 
shown in FIG. 10, exposing cutting edge 74A. The wire loop 76 is then 
pulled forcing the graft against the cutting surface 74A to sever the 
graft. 
FIGS. 11, 12 and 13 show an embodiment of the invention which can be 
introduced into the vasculature percutaneously and which requires no 
additional catheters to deploy the cephalic and caudal stents. 
This device comprises a catheter or sheath 80 which envelopes the graft 44R 
and a balloon catheter 82 which extends through the interior of the graft 
44R. The balloon catheter 82 supports proximal and distal balloons 84, 85, 
86 and 87. The catheter 82 will include four inflation lumens (not 
numbered) so that the four balloons can be selectively inflated and 
deflated. 
A caudal stent 88 is mounted on deployment balloon 85 and a cephalic stent 
91 is mounted on the deployment balloon 87. As is conventional, the distal 
end of the graft 44R is attached to the cephalic stent 91, for example, by 
sewing. 
As best shown in FIG. 13, the cutting device in this case comprises a 
circular blade 89 mounted for rotation within sheath 80. The proximal 
balloon 84 when expanded, pushes the graft 44R into contact with the blade 
89 so that the graft can be cut as described below. 
As indicated above, an advantage of this embodiment is that it can be 
introduced percutaneously into the patient's vasculature. Accordingly, in 
using the embodiment of FIGS. 11-13, after the guidewire is in position, 
the entire assembly including the graft/stent complex, balloon catheter 82 
and sheath 80 are advanced along the guidewire until the cephalic stent 91 
is properly positioned, as indicated by contrast solution. The guide 
sheath 80 is then retracted to expose the stent 91 which is deployed by 
expanding balloon 87, thus pinning the distal end of the graft. Deployment 
balloon 87 is next deflated and the balloon catheter 82 and sheath 80 
retracted. The catheter 82 is retracted until the distal end of the sheath 
80 is positioned just below the attachment point J. This is determined by 
means of the contrast solution introduced through tube 60 as in the 
previous embodiments. 
The balloon catheter 80 is then retracted through the graft 44R until the 
balloon 84 is positioned in the distal end of the sheath 80 as shown in 
FIG. 12. Proper positioning can be assured by external markings on the 
balloon catheter which are visible to the surgeon. With the balloon 
catheter 82 in position, the balloons 84 and 86 are inflated. The expanded 
distal balloon 86 holds the graft 44R in position so that it does not 
retract after the graft has been cut to size. (In place of a balloon 84, a 
solid material may be employed to serve as an anvil for the cutting 
blade.) The proximal balloon 84 forces the graft against the circular 
blade 89. The guide sheath 80 is then rotated from its proximal end 
causing the circular blade 89 to form an annular cut in graft 44R in the 
desired location. Balloons 84 and 86 are then deflated and the severed 
proximal portion of graft 44R removed, through the incision H. The stent 
88 may be then be deployed by expanding the balloon 85 beneath the stent 
in conventional fashion. The balloon catheter 82 and guide sheath 80 are 
then removed, leaving the graft in place pinned by both the cephalic and 
caudal stents as desired. 
FIGS. 14-17 illustrate a "guillotine" type of cutting arrangement which 
would be used in much the same way as the embodiments of FIGS. 2-10, i.e. 
with the cutting device encircling the graft. In this embodiment, a 
catheter 90 is supported in a base 92 at its proximal end and terminates 
in a head 94 at its distal end which contains the cutting mechanism. The 
cutting mechanism comprises a fixed blade 96 secured to head 94 and a 
movable blade 98 which is biased by a pair of return springs 100 to its 
open position. The movable blade 98 is operated by a pair of pull cables 
102 which extend from the base 92 through the catheter 90 into the head 
94. The head includes horizontally arrayed pulleys 104 at its distal end 
and vertically arrayed pulleys 106 at its proximal end. Each of the pull 
cables 102 passes over a vertically arrayed pulley 106, around a 
horizontal pulley 104, and through a return spring 100 and a suitable bore 
(not numbered) within the movable blade 98. Each cable is anchored in 
conventional fashion at the proximal end of the blade 98 (FIG. 16). 
As shown in FIG. 17, the proximal ends of the pull cables 102 are attached 
to a pin 110 which slides in slots 112 within the base 92. Pin 110 
terminates in control knobs 114 which are accessible to the surgeon. The 
surgeon, by pushing the control knob 114 proximally against the force of a 
return spring 116 exerts a force on the movable blade 98 which will pull 
it toward the fixed blade 96 to sever a graft which is positioned between 
the blades. 
A sixth type of cutting device is shown in FIG. 18. This device is an iris 
type cutter which includes a series of blades 120 which may be movable in 
much the same way as the iris of a camera. Movement of the blades 120 is 
controlled by a rotatable knob 122 at the proximal end of the catheter 
through an elongated rod 124 and a suitable transmission (not shown). The 
iris blades 120 may also be actuated by means of pull wires. 
It is contemplated that the cutting device will be packaged as part of an 
overall system. In such a case, the cutting device will be introduced with 
the graft, with the stent deploying catheter inside the graft as is 
customary. After the cephalic stent is deployed, the stent deployment 
catheter can be removed and the cutting device positioned to cut the 
caudal end of the graft. In this arrangement, it is likely, though not 
necessary, that the cutting device will be positioned by pulling on the 
catheter 50, which is generally preferable to pushing although both 
arrangement are contemplated by the invention. 
The invention contemplates the use of any type of cutting mechanism besides 
those illustrated in this specification for the purpose of cutting a graft 
to size after it has been situated in the vasculature. Furthermore, 
although the invention has been described in the context as U.S. Pat. No. 
5,507,769, it is anticipate and intended that the invention will be used 
in any situation where a graft may be used.