Method and apparatus for catheterization to dilate vascular blockage

An method for implanting a coiled prosthesis within a body passageway having a longitudinally extending central axis first places a coiled prosthesis upon a catheter in a coiled, smaller diameter configuration. The prosthesis and catheter are inserted into the body passageway by catheterization of the body passageway. The prosthesis is expanded in order to unwind the coiled ring prosthesis to a larger diameter configuration that has a diameter larger than the smaller diameter configuration of the prosthesis initially. The prosthesis forms an annular ring having spaced apart first and second annular surfaces. The body passageway is supported in a direction away from the annular ring and along the passageway wall with multiple, longitudinally extending strut support members that each extend away from the ring, and each of which extends partially circumferentially around the passageway. After the prosthesis has been expanded, the catheter is withdrawn from the body passageway.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention relates to the treatment of coronary artery disease 
by mechanical dilation of blockages in the coronary arteries. More 
particularly, the present invention relates to a method and apparatus for 
dilating blockage in coronary arteries wherein a catheter assembly carries 
a balloon to the blockage site in a patient's artery, and the balloon is 
expanded to uncoil a coiled ring structure having longitudinally extended 
struts is carried upon the balloon, and which locks to remain in an 
uncoiled position, holding the blockage, flap or dissection in open 
dilated position. 
2. General Background 
A common medical condition that threatens thousands of lives is caused by 
blockage of the coronary arteries. Medical procedures have been designed 
to remove the blockage in many cases so that increased blood flow travels 
through the previously diseased artery. Restenosis means that coronary 
artery blockage returns. It is though that restenosis is due to tissue 
growing in the inner lining of the artery as it heals. Approximately 30% 
of the patients undergoing PTCA will experience restenosis. Several 
procedures have been developed in hopes of reducing the restenosis rate. 
Atherectomy is a technique by which the blockage is actually removed. It 
is often times referred to as the roto-rooter. This technique initially 
demonstrated promise but it seems that it does not effect restenosis. 
Another technique is stent implantation. A stent is a device that is 
deployed in the vessel to pin back flaps and prevent elastic recoil. Early 
data suggest that this procedure may reduce stenosis. 
The other problem with PTCA is acute occlusion. Occlusion occurs when the 
artery closes off completely following balloon dilatation. This problem is 
usually the result of one of two things. A clot can form at the PTCA site 
and obstruct the vessel, or a dissection can form which is basically a 
flap made up of the inner and middle layers of the artery. Severe 
dissections have been treated by long balloon inflation times in hopes of 
pinning up the flap, by atherectomy where by you go in and cut off the 
flap, and by stenting which pins up the flap mechanically. 
There are several stents currently being researched in the coronary and 
peripheral circulation, the most well known is the Palmaz stent. It is a 
stainless steel tube that is prepared by cutting a series of slots in it. 
It is then placed on a balloon. When the balloon is inflated the tube 
expends to the diameter of the balloon and foreshortens the stent upon 
expansion. 
Another stent is the Schneider or Wall stent. This is a self-expanding 
stent. It is similar in design to a Chinese finger cuff. When elongated 
its diameter is smaller. When allowed to shorten along its longitural axis 
its diameter increases. Following deployment in a blood vessel it is 
further expanded with a balloon. Various patents have issued for stents 
and for catheter arrangements that are directed to the problem of coronary 
blockage and restenosis. 
U.S. Pat. No. 4,733,665, entitled "Expandable Intraluminal Graft, And 
Method And Apparatus For Implanting An Expandable Intraluminal Graft," 
issued to Julio C. Palmaz, discloses a graft that is expanded within a 
blood vessel by an angioplasty balloon associated with a catheter to 
dilate and expand the lumen of a blood vessel. The graft may be made of a 
wire mesh tube. 
U.S. Pat. No. 5,049,131, entitled "Balloon Catheter," issued to Jacobus A. 
C. Deuss, discloses a balloon catheter for the widening of passages in the 
body, such as blood vessels. The apparatus comprises a tubular body 
connected at one side to the interior of a cylindrical balloon and at 
another side to a pump unit. The balloon can be enlarged from a first 
predetermined diameter to a second predetermined diameter without 
completely withdrawing the catheter from the body passages. 
U.S. Pat. No. 5,066,298, entitled "Article And Method Of Sheathing 
Angioplasty Balloons," issued to Robert L. Hess, discloses a 
pre-compressed angioplasty balloon catheter and method of manufacture 
wherein the balloon portion of the catheter is wrapped for storage and for 
minimizing its outside diameter for purpose of insertion into the body. 
U.S. Pat. No. 5,100,381, entitled "Angioplasty Catheter," issued to Matthew 
M. Burns, discloses an over-the-wire balloon for use in angioplasty and 
includes a dual lumen shaft formed by a multisection outer tube and 
multisection inner tube. The outer tube includes a first thin wall outer 
tube section which is connected to a manifold at its proximal end. The 
outer tube also includes a second outer tube section which is attached to 
the distal end of the first outer tube section and which has a greater 
flexibility. The inner tube has a first thin wall inner tube section which 
extends generally coaxially through the first outer tube section and into 
the interior of the second outer tube section. The inner tube also 
includes a second thin wall inner tube section which is attached to the 
distal end of the first inner tube section and extends distally beyond the 
distal end of the outer tube. A balloon is attached to the distal ends of 
the outer and inner tubes. The inner tube sections have a coating of a low 
friction material, such as polyimide-polytetrafluoroethylene composite, on 
their inner walls to facilitate movement of a guide wire through the guide 
wire lumen of the inner tube. 
U.S. Pat. No. 5,100,429, entitled "Endovascular Stent And Delivery System," 
issued to Edward L. Sinofsky et al., discloses an uncured or partially 
cured, collagen-based material that is delivered to a selected site in a 
blood vessel and is crosslinked in the blood vessel by laser energy or 
other suitable energy to form an endovascular stent. The collagen-based 
material can be delivered to the blood vessel as a coating on an 
inflatable balloon mounted on the distal end of a catheter. The 
collagen-based material can also be delivered to the blood vessel in 
liquid form and forced through a porous balloon to form a tubular 
configuration. The collagen-based material is preferably crosslinked by 
laser radiation carried through an optical fiber to a diffusing tip 
located within the balloon. In another embodiment, an endovascular stent 
is formed by rolling a flexible sheet of biologically-compatible material 
onto a an outside surface of an inflatable balloon. A crosslinkable 
collagen-based adhesive is used to adhere overlapping portions of the 
sheet together in the blood vessel and can be used to attach the stent to 
an inside surface of the blood vessel. The collagen-based adhesive is 
crosslinked in the blood vessel by application of laser energy or other 
suitable energy. A photodegradable adhesive can be used on an inside 
surface of the stent to releasably attach the stent to the inflatable 
balloon. 
U.S. Pat. No. 5,102,417, entitled "Expandable Intraluminal Graft, And 
Method And Apparatus For Implanting An Expandable Intraluminal Graft," 
issued to Julio C. Palmaz, discloses a plurality of expandable and 
deformable intraluminal vascular grafts that are expanded within a blood 
vessel by an angioplasty balloon associated with a catheter to dilate and 
expand the lumen of a blood vessel. The grafts may be thin-walled tubular 
members having a plurality of slots disposed substantially parallel to the 
longitudinal axis of the tubular members, and adjacent grafts are flexibly 
connected by at least one connector member. 
SUMMARY OF THE INVENTION 
The present invention provides and improved method for implanting a coiled 
vascular ring prosthesis within a body passageway having a longitudinally 
extending central axis. 
The method first places a coiled prosthesis upon a catheter in a coiled, 
smaller diameter configuration. 
The prosthesis and catheter are inserted into the body passageway by 
catheterization of the body passageway. 
The prosthesis is expanded in order to unwind the coiled prosthesis to a 
larger diameter configuration that has a diameter larger than the smaller 
diameter configuration of the prosthesis initially. 
The prosthesis forms an annular ring having spaced apart first and second 
annular surfaces. The length of the ring between first and second annular 
surfaces can be very small in relation to the overall largest diameter of 
the ring. This feature allows the ring to be placed adjacent branches of 
vessels, and in curves as well as adjacent blockages that are very small. 
The body passageway is supported in a direction away from the annular ring 
and along the passageway wall with multiple, longitudinally extending 
strut support members that each extend away from the ring, and each of 
which extends partially circumferentially around the passageway. 
After the prosthesis has been expanded, the catheter is withdrawn from the 
body passageway. 
In the preferred embodiment, the support members are spaced 
circumferentially about the ring. 
In the preferred embodiment, the coiled prosthesis is uncoiled by inflating 
a balloon. 
In the preferred embodiment, the prosthesis is a coiled ring member having 
a first predetermined collapsed smaller diameter, a central opening, and 
an inflatable balloon that occupies the central opening during insertion. 
In the preferred embodiment, the prosthesis is metallic or plastic. 
In the preferred embodiment, the prosthesis can be coated or impregnated 
with medication such as heparin, for example. 
In the preferred embodiment, the catheter carries an inflatable balloon 
that uncoils the prosthesis and further comprising the step of locking the 
ring into the second maximum diameter to prevent a return to a coiled 
position with a diameter smaller than the second maximum diameter.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT: 
FIGS. 1A-1B illustrate a normal coronary artery designated by the numeral 
10 having unrestricted blood flow designated schematically by arrow 11 in 
FIG. 1A. Healthy coronary artery 10 has a wall 14 comprised of an inner 
layer 14A (intima), a media layer of thick muscular tissue 14B, and an 
outer layer (adventitia) 14C. Otherwise, the lumen 12 of healthy artery 10 
is unrestricted and open for blood flow as defined by the inner layer 14A. 
In FIGS. 2A-2B, a coronary artery 10 is illustrated that has become 
diseased with heavy plaque 13 buildup and having restricted blood flow 
through the restricted lumen 15. Arrow 16 designates restricted blood flow 
which must pass through the very small restricted lumen 15 that has become 
a restriction for blood flow because of the buildup of heavy plaque 13 
occupying the majority of the normal dimensions of lumen 12. 
In FIGS. 3A-3B, a typical balloon angioplasty is used in the prior art is 
shown which as been used to compress the plaque inside the artery. Balloon 
17 is placed in lumen 12 with a coronary guide wire 18 as is known in the 
art. Balloon 17 is initially deflated during catheterization of artery 10. 
However, when the obstruction and restricted lumen 15 is reached, balloon 
17 is inflated and plaque buildup 13 compressed. In FIGS. 3A-3B, 
compressed plaque is designated generally by the numeral 20. 
One of the problems with balloon angioplasty as illustrated in FIGS. 3A and 
3B, is that the balloon angioplasty can sometimes damage artery wall 14. 
In FIG. 4A, guide wire 18 has been used to place balloon 17 adjacent an 
area of plaque buildup, designated as 20 in FIG. 4A. In FIG. 4A, balloon 
17 has been deflated following expansion of the balloon used to compress 
plaque inside artery 10. However, the inflated balloon 17 has damaged a 
portion of the artery wall, the damaged area indicated as 21. In FIG. 4B, 
the damaged area 21 is illustrated more particularly showing the torn 
inner layer 14A and damaged media layer 14B. 
FIG. 5A shows a perspective view of artery 10 and damaged area 21 of artery 
wall 14. A guide wire 22 has been placed in the lumen 12 of artery 10. 
After the guide wire is placed, according to the method of the present 
invention, a deflated balloon 23 carrying coiled ring structure 24 is 
inserted into the lumen 12 of artery 10. Ring 24 is coiled tightly around 
deflated balloon 13 so that the initial diameter of ring 24 is a smallest 
diameter which allows catheterization of artery 10 using wire 22 to carry 
deflated balloon 23 and coiled ring 24 into position adjacent damaged area 
21. 
FIGS. 8 and 9A illustrate in section, the placement of guide wire 22, 
deflated balloon 23, and ring structure 24 in an initial position during 
catheterization and prior to inflation of balloon 23. 
In FIGS. 9A-9C, sequential views respectively illustrate guide wire 22 
prior to the inflation of balloon 23, in FIG. 9B, balloon 23 beginning to 
inflate, and in FIG. 9C, balloon 23 has been further inflated so that 
coronary ring 24 expands toward a maximum diameter. 
In FIG. 10, the ring structure 25 can be seen as comprising an annular ring 
portion 27 having a pair of annular edges 28, 29. The length of the 
annular ring portion as measured from annular edge 28 to annular edge 29 
is much smaller than the largest diameter of the ring portion 27 upon full 
expansion. For example the length can be one millimeter for a ring 27 with 
a 3 mm diameter upon expansion. This allows the ring structure 25 to be 
placed adjacent branch lines of an artery, and in restricted spaces, and 
in curved portions of arteries. 
A longitudinally extending strut 30 extends longitudinally, generally 
parallel to the central longitudinal axis of bore 12. Similarly, strut 31 
extends from annular surface 28 and away from ring structure 27, the strut 
31 also extending generally parallel to the central longitudinal axis of 
lumen 12. In FIG. 10, wire 22 basically defines the central longitudinal 
axis of lumen 12 once balloon 26 is inflated. Central opening 32 in ring 
structure 27 allows unrestricted blood flow through ring structure 24. 
Struts 30, 31 extend longitudinally and in opposite directions from ring 
27. Further, each strut tracks the inner layer 14A of artery wall 14 when 
ring structure 24 has been fully expanded. Thus, the struts 30, 31 
function to hold the ring 27 upright, preventing its rotation or tipping 
with respect to the central longitudinal axis of lumen 12. 
In FIG. 14, an enlarged view of ring structure 24 illustrates the ring if 
laid out flat, rather than in the coiled position. Ring structure 24 
includes the annular ring 27 portion having a first end 33 and a second 
end 34. The end portion 33 provides a pointed member 34 that is bent 
inwardly as shown in FIG. 8 so that as the annular ring 27 expands, the 
pointed tip 35 registers with slot 36 of locking tab 37. The locking tab 
37 includes side portions 38, 39. Slot 36 extends transversely across 
locking tab 37, terminating at end portions 40, 41 which provide a lateral 
dimension to slot 36 that is slightly smaller than the width of tab 37 
between its edge portions 38, 39. 
In FIG. 16, a strut 30 is shown in section, as including a raised portion 
42 that can extend the full length of strut 30 between its point of 
attachment 43 to ring 27 and end portion 44 of strut 30. Raised portion 42 
provides an increased cross section and thus a reinforcement to strut 30. 
Depending upon the length of strut 30 or 31, the configuration of raised 
portion 42 could be varied to provide sufficient strength so that struts 
30, 31 do not unduly collapse or bend during use. 
In FIG. 17, a second embodiment of the ring structure is illustrated, 
designated generally by the numeral 45. In the embodiment of FIG. 17, the 
ring structure provides a plurality of slots 46-48 so that the ring 
diameter can be adjusted to ever larger diameters as the balloon expands 
the annular ring 49 portion of the ring structure 45. The annular ring 
portion 49 provides end portions 50, 51 with the plurality of slots being 
carried by end portion 50, as shown in FIG. 17. The end portion 51 carries 
a pointed tip portion 52 that registers with each adjustable slot 46-48 as 
the balloon expands. This allows the cardiologist or technician to expand 
the ring 49 into an initial first diameter and then increase that diameter 
if desired. This also allows the ring to be expanded to larger diameters 
in subsequent procedures such as when blockage returns. 
Each of the longitudinally extending struts 53, 54 carries a reinforcement 
55, 56 respectively for preventing excessive bending of the struts during 
use. 
As an example, the ring 49 could be adjusted to a first opened position of 
about 2.0 mm corresponding to a placement of the pointed tip 52 in the 
first slot 46. Further, the second slot 47 would represent a diameter of 
2.5 mm for the annular ring 49. The slot 48 represents an adjustment 
position for a diameter of 3.0 mm. These dimensions could be provided for 
a first smaller ring, adjusted to the above-referenced positions as 
desired. However, a larger ring having adjustment positions of 3.5 mm, 4.0 
mm, and 4.5 mm could also be provided so that a user achieves a broad 
range of ring 49 maximum diameters by providing the multiple slots 46-48 
on each ring and by providing numerous rings of ever increasing maximum 
diameter. 
The following Table 1 lists the part numbers and corresponding part 
descriptions as used herein in the written specification and the numbers 
as used in the attached drawing figures. 
TABLE 1 
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TS LIST 
Part Number Description 
______________________________________ 
10 coronary artery 
11 arrow 
12 lumen 
13 plaque 
14 wall 
14A inner layer 
14B media layer 
14C outer layer 
15 restricted lumen 
16 arrow 
17 balloon 
18 guide wire 
19 compressed plaque 
20 plaque buildup area 
21 damaged area 
22 guide wire 
23 collapsed balloon 
24 ring structure 
25 locking end portion 
26 inflated balloon 
27 annular ring 
28 annular edge 
29 annular edge 
30 strut 
31 strut 
32 opening 
33 end portion 
34 end portion 
35 pointed tip portion 
36 slot 
37 locking tab 
38 edge 
39 edge 
40 end portion of slot 
41 end portion of slot 
42 raised portion 
43 attachment 
44 end portion 
45 ring 
46 slot 
47 slot 
48 slot 
49 annular ring 
50 end 
51 end 
52 pointed tip 
53 strut 
54 strut 
55 reinforcement 
56 reinforcement 
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Because many varying and different embodiments may be made within the scope 
of the inventive concept herein taught, and because many modifications may 
be made in the embodiments herein detailed in accordance with the 
descriptive requirement of the law, it is to be understood that the 
details herein are to be interpreted as illustrative and not in a limiting 
sense.