ANGIOPLASTY MARKER AND GUIDE CATHETER WITH BIFRUCATION SITE STENTING, APPARATUS AND METHOD

Abstract

An angioplasty apparatus for facilitating accurate placement of a lumen stent for dilating a stenosis, the apparatus includes arcuate low pressure balloon segment(s) connected at a distal end of a guiding catheter with gap(s) to facilitate blood flow during a stenting procedure. Optimal positioning of a stent at a lumen bifurcation is facilitated to obviate any tendency of a stent to miss a proximal end of a stenosis branch lumen while concomitantly preventing the stent from protruding into an original lumen, such as a patient's aorta.

Claims

1. An angioplasty marker and guide catheter apparatus for facilitating accurate placement of a lumen stent for dilating a stenotic segment at a lumen bifurcation junction, said angioplasty marker and guide catheter apparatus comprising: a marker and guide catheter assembly having a proximal end and a distal end, said guide catheter assembly including, a tubular conduit, a marker and guide balloon assembly connected to a distal end of said guide catheter tubular conduit, said marker and guide balloon assembly including at least one inflatable marker and guide balloon segment, said at least one inflatable marker and guide balloon segment having an arcuate, circumferential extent less than or equal to three hundred forty degrees about a distal end of said tubular conduit, and an inflation conduit connected to said tubular conduit and being operable to be connected to an inflation syringe at a proximal end of said guide catheter assembly and to said at least one inflatable marker and guide balloon segment mounted at a distal end of said tubular conduit for selective delivery of marker fluid under low pressure to said at least one inflatable marker and guide balloon segment.

2. An angioplasty marker and guide catheter apparatus for facilitating accurate placement of a lumen stent for dilating a stenotic segment at a lumen bifurcation junction as defined in claim 1 wherein said marker and guide balloon assembly having at least one inflatable segment comprises: an arcuate shaped balloon segment mounted at the distal end of said marker and guide catheter assembly, said arcuate shaped balloon segment subtends an arc of at least approximately forty five degrees.

3. An angioplasty marker and guide catheter apparatus for facilitating accurate placement of a lumen stent for dilating a stenotic segment at a lumen bifurcation junction as defined in claim 1 wherein said marker and guide balloon assembly having at least one marker and guide balloon segment comprises: at least two independent and symmetrically opposing arcuate shaped balloon segments mounted at the distal end of said guide catheter assembly.

4. An angioplasty marker and guide catheter apparatus for facilitating accurate placement of a lumen stent for dilating a stenotic segment at a lumen bifurcation junction as defined in claim 3 wherein: each of said two independent and symmetrically opposing arcuate shaped marker and guide balloon segments mounted at the distal end of said guide catheter assembly subtends an arc of at least approximately one hundred degrees but less than approximately one hundred and forty degrees.

5. An angioplasty marker and guide catheter apparatus for facilitating accurate placement of a lumen stent for dilating a stenotic segment at a lumen bifurcation junction as defined in claim 3 wherein: each of said two independent and symmetrically opposing arcuate marker and guide balloon segments mounted at the distal end of said guide catheter assembly subtends an arc of at least approximately one hundred twenty degrees.

6. An angioplasty marker and guide catheter apparatus for facilitating accurate placement of a lumen stent for dilating a stenotic segment at a lumen bifurcation junction as defined in claim 1 wherein said marker and guide balloon having at least one inflatable marker and guide segment comprises: three independent and symmetrically positioned arcuate shaped marker and guide balloon segments mounted at the distal end of said guide catheter assembly.

7. An angioplasty marker and guide catheter apparatus for facilitating accurate placement of a lumen stent for dilating a stenotic segment at a lumen bifurcation junction as defined in claim 6 wherein: each of said three independent and symmetrically opposing arcuate shaped marker and guide balloon segments mounted at the distal end of said guide catheter assembly subtends an arc of at least sixty degrees but less than one hundred degrees.

8. An angioplasty marker and guide catheter apparatus for facilitating accurate placement of a lumen stent for dilating a stenotic segment at a lumen bifurcation junction as defined in claim 1 wherein said marker and guide balloon assembly having at least one inflatable marker and guide balloon segment comprises: an arcuate marker and guide balloon segment mounted at the distal end of said guide catheter assembly, said arcuate marker and guide balloon segment subtends an arc of at least approximately forty five degrees.

9. An angioplasty apparatus, with stent, for facilitating accurate placement of a lumen stent for dilating a stenosis at a bifurcation, said angioplasty apparatus comprising: a guide catheter assembly having a proximal end and a distal end, said guide catheter assembly including, a marker and guide balloon connected to a distal end of said guide catheter assembly, said marker and guide balloon including at least one inflatable marker and guide balloon segment, said at least one inflatable marker and guide balloon segment having a circumferential extent less than or equal to three hundred forty degrees, and an inflation conduit connected to said guide catheter assembly and being operable to be affixed to an inflation syringe at a proximal end of said guide catheter assembly and to said at least one inflatable marker and guide balloon segment at a distal end of said guide catheter assembly; and a stent catheter assembly operable to be inserted through said guide catheter assembly, said stent catheter assembly comprising, an angioplasty guide wire operable to extend through said guide catheter assembly and through a stenosis segment of a patient, a percutaneous dilating catheter mounted upon said guide wire and being operable to be inserted over said guide wire and through said guide catheter assembly to a stenosis segment of a patient for operably dilating a patient's blood vessel at a stenosis segment location, and means connected to a proximal end of said percutaneous dilating catheter for marking a proximal end of said dilating catheter stent within a patient's blood vessel.

10. An angioplasty apparatus, with stent, for facilitating accurate placement of a lumen stent for dilating a stenosis at a bifurcation as defined in claim 9 wherein said marker and guide balloon having at least one inflatable marker and guide balloon segment comprises: at least two independent and symmetrically opposing arcuate marker and guide balloon segments mounted at the distal end of said guide catheter assembly subtends an arc of approximately one hundred and forty degrees.

11. An angioplasty apparatus, with stent, for facilitating accurate placement of a lumen stent for dilating a stenosis at a bifurcation as defined in claim 9 wherein said marker and guide balloon having at least one inflatable marker and guide balloon segment comprises: at least three independent and symmetrically positioned arcuate marker and guide balloon segments mounted at the distal end of said guide catheter assembly wherein each of said arcuate marker and guide balloon segments subtends an arc of at least approximately one hundred degrees.

12. An angioplasty apparatus, with stent, for facilitating accurate placement of a lumen stent for dilating a stenosis, said angioplasty apparatus comprising: a guide catheter assembly having a proximal end and a distal end, said guide catheter assembly including, a marker and guide balloon connected to a distal end of said guide catheter assembly, said marker and guide balloon including at least one inflatable marker and guide balloon segment, said at least one inflatable marker and guide balloon segment having a circumferential extent less than or equal to three hundred forty degrees, and an inflation conduit connected to said guide catheter assembly and being operable to be affixed to an inflation syringe at a proximal end of said guide catheter assembly and to said at least one inflatable marker and guide balloon segment at a distal end of said guide catheter assembly; and a stent catheter assembly operable to be inserted through said guide catheter assembly, said stent catheter assembly comprising, an angioplasty guide wire operable to extend through said guide catheter assembly and through a stenosis segment of a patient blood lumen, a percutaneous dilating catheter mounted upon said guide wire and being operable to be inserted over said guide wire and through said guide catheter assembly to a stenosis segment of a patient's blood vessel for operable dilating a patient's blood vessel at a stenosis segment location, and at least one low pressure, marker balloon segment connected to a proximal end of said percutaneous dilating catheter, said marker balloon segment including at least one inflatable marker balloon segment having a circumferential extent less than or equal to three hundred and forty degrees.

13. An angioplasty apparatus, with stent, for facilitating accurate placement of a lumen stent for dilating a stenosis as defined in claim 12 wherein said low pressure, marker balloon having at least one inflatable marker balloon segment comprises: an arcuate shaped marker balloon segment mounted at the proximal end of said percutaneous dilating catheter assembly, said arcuate shaped marker balloon segment subtends an arc of approximately at least forty five degrees.

14. An angioplasty apparatus, with stent, for facilitating accurate placement of a lumen stent for dilating a stenosis as defined in claim 12 wherein said low pressure, marker balloon having at least one inflatable marker segment comprises: at least two marker balloon segments.

15. An angioplasty apparatus, with stent, for facilitating accurate placement of a lumen stent for dilating a stenosis as defined in claim 12 wherein said low pressure, marker balloon having at least one inflatable marker segment comprises: at least three marker balloon segments.

16. A method for dilating a stenosis segment at a bifurcation junction of a human circulatory system, said method comprising the steps of: inserting percutaneously a guide catheter assembly having at least one marker and guide balloon segment connected to a distal end of said guide catheter assembly, an angioplasty guide wire extending coaxially through said guide catheter assembly, and a balloon stent catheter coaxially extending along the guide wire; extending the guide wire through a stenosis at a bifurcation junction of a human circulatory system; extending a collapsed stent balloon and surrounding stent over the guide wire and at least partially through a bifurcation stenosis to be treated; inflating, with a low pressure radiopaque marker fluid, at least one marker balloon segment connected at a distal end of the guide catheter to expand the at least one marker balloon segment to a degree larger than a bifurcation site of interest having a stenosis at the bifurcation site; positioning the guide catheter at least one marker balloon segment at the bifurcation opening of a stenosis region to be treated; extending a catheter balloon with stent and a radiopaque marker means mounted at a proximal end of the catheter balloon to a position at least partially past the stenosis to be treated; drawing back the catheter balloon with stent and proximal marker means until the marker means registers with the at least one marker balloon segment at a distal end of the guide catheter at the bifurcation junction to be treated; expanding the stent balloon with a high pressure to extend a wire mesh stent outwardly to radially enlarge the stenosis at the bifurcation junction being treated; collapsing the high pressure stent balloon; and withdrawing the guide wire, the collapsed stent balloon and the marker and guide catheter percutaneously from a patient.

17. A method for dilating a stenosis at a bifurcation junction of a human circulatory system as defined in claim 16 wherein said at least one marker and guide balloon at a distal end of said guide catheter comprises: two opposed marker and guide balloon segments with each having a circumferential extent of approximately one hundred and forty degrees and inflating each marker and guide balloon, independently, with a low pressure radiopaque marker media to conform the marker and guide balloon segments at a distal end of said guide catheter to approximately a coaxial posture of the distal end of the guide catheter with a stenosis lumen to be treated.

18. A method for dilating a stenosis lesion at a bifurcation junction of a human circulatory system as defined in claim 16 wherein said at least one marker and guide balloon comprises: three marker balloon segments with each having a radial extent of approximately one hundred degrees and inflating each marker and guide balloon, independently, with a low pressure radiopaque marker media to conform the marker and guide balloon segments at a distal end of said guide catheter to approximately a coaxial posture of the distal end of the guide catheter with a stenosis lumen to be treated.

19. A method for dilating a stenosis lesion of a human circulatory system, said method comprising the steps of: inserting percutaneously a guide catheter assembly having at least one marker and guide balloon segment connected to a distal end of said guide catheter assembly, an angioplasty guide wire extending coaxially through said guide catheter assembly, and a balloon stent catheter coaxially extending along the guide wire; inflating, with a low pressure radiopaque marker fluid, at least one marker balloon segment connected at a distal end of the guide catheter to expand the at least one marker balloon segment to a degree larger than a branch lumen of a patient to be treated; extending the guide wire through a stenosis of a patient's circulatory system; extending a collapsed stent balloon catheter and surrounding stent over the guide wire and at least partially through a stenosis segment to be treated; positioning the guide catheter and the at least one marker balloon segment at a branch of a patient's circulation system to be treated; extending a catheter balloon and stent with a marker means at a proximal end of the balloon stent at least partially through a stenosis to be treated; withdrawing the catheter balloon and stent with marker means at a proximal end thereof back until said marker means of the catheter balloon and stent joins with the at least on marker balloon segment connected to a distal end of the guide catheter at a proximal end of a stent to be treated using the low pressure marker balloon as location identification while permitting a flow of blood and marker fluid through the stenosis site positioning a proximal end of the stent at a proximal end of a patient's stenosis segment to be treated; expanding the stent balloon with a high pressure fluid to extend a wire mesh stent scaffolding outwardly to radially enlarge the stenosis at the patient stenosis site being treated; collapsing the high pressure stent balloon and the at least one low pressure marker and guide balloon; and withdrawing the guide wire, the collapsed stent balloon, and the guide catheter with the at least one collapsed marker and guide balloon segment percutaneously from a patient.

20. A method for dilating a stenosis lesion of a human circulatory system as defined in claim 19 wherein said step of inflating, with a low pressure radiopaque marker fluid, at least one marker balloon segment connected at a distal end of the guide catheter comprises the step of: independently inflating with a marker fluid at least two low pressure marker and guide balloon segments at a proximal end of the guide catheter.

21. A method for dilating a stenosis lesion of a human circulatory system as defined in claim 19 wherein said step of inflating, with a low pressure radiopaque marker fluid, at least one marker balloon segment connected at a distal end of the guide catheter comprises the step of: independently inflating with a marker fluid at least three low pressure marker and guide balloon segments at a proximal end of the guide catheter.

Description

THE DRAWINGS

[0023] Numerous advantages of the present invention will become apparent from the following detailed description of preferred embodiments taken in conjunction with the accompanying drawings wherein:

[0024] FIG. 1 is an anatomic, silhouette, front view of basic components of a human heart and aorta vascular system;

[0025] FIG. 2 is an anatomic, silhouette, back view of a similar human heart and aorta vascular system as depicted in FIG. 1;

[0026] FIG. 3 is axonometric view of an aorta segment and a branch artery, such as a renal artery, for example, extending at essentially a right angle with a plaque stenosis at the aorta branch junction or bifurcation and a guide catheter carrying a guide wire and balloon catheter, with stent, for accurate placement of the stent at the stenosis occlusion;

[0027] FIG. 4A is a side, partial cross-sectional view of a stent being placed at a renal artery bifurcation junction of the type depicted in FIG. 3;

[0028] FIG. 4B is a bubble enlargement of a segment of the aorta—lateral renal artery bifurcation junction with initial entry of a balloon stent carried within a guide catheter and being advanced over a guide wire;

[0029] FIG. 5A is a side cross-sectional view of a balloon stent placement as depicted in FIG. 4A with the stent shown in an accurate position at the aorta renal artery bifurcation junction by a guide catheter marker balloon segment abutted against the aorta bifurcation junction;

[0030] FIG. 5B is a bubble enlargement of a segment of the aorta—renal artery bifurcation junction showing a low pressure marker balloon segment abutted against the aorta bifurcation junction for accurate positioning of a bifurcation junction balloon stent;

[0031] FIG. 6 is an end view and partial cross-sectional view, taken in the direction of arrow “A” in FIG. 5B to disclose interior detail, of one preferred embodiment of an arcuate, low pressure, marker balloon positioned at a distal end of a guide catheter, at a bifurcation junction of a renal artery with a side wall segment of an aorta;

[0032] FIG. 7 is an end view and partial cross-sectional view of another preferred embodiment of an arcuate, low pressure, marker balloon system of opposing balloon segments positioned at a distal end of a guide catheter, at a bifurcation junction of a renal artery with a side wall segment of an aorta;

[0033] FIG. 8 is an end view and partial cross-sectional view of yet another preferred embodiment of an arcuate, low pressure, marker balloon system of three symmetric segments positioned at a distal end of a guide catheter, at a bifurcation junction of a renal artery with a side wall segment of an aorta; and

[0034] FIGS. 9A-9C are sequence views disclosing a method of use of the subject guide catheter for angioplasty, with bifurcation stenting sequence for accurate placement of a balloon stent at, for example, a bifurcation junction of an aorta with a renal artery branch.

DETAILED DESCRIPTION

[0035] In this description the expression “approximately” or “generally” is intended to mean at or near but not always exactly such that an exact dimension or location is not considered critical in those contexts where those expressions appear. In this description focus will be directed to a guide catheter for angioplasty, with bifurcation stenting, at a renal artery junction with an aorta. This renal artery bifurcation focus, however, is intended to be one of illustration and example and is not intended as a limitation. The subject invention is appropriate and advantageous for most human vascular system bifurcation locations and junctions where a guide catheter finds application.

[0036] Turning initially now to FIGS. 1 and 2 there is shown a front 10 and back 12 view of a human figure with outline views of generalized and basic components of a circulatory system with front and back views of a heart 14, an ascending aorta 16 connected to a left ventricle of the heart, an aorta arch 18 and a descending abdominal aorta 20 with renal branch arteries 22 and 24 extending to left and right kidneys 26 and 28 respectively. As indicated above, the human body has a number of arteries stemming from the aorta but for purposes of this description only the renal arteries going to a patient's kidneys are depicted as being representative.

[0037] In addition to lateral left and right renal arteries extending from a patient's aorta to a patient's kidneys FIGS. 1 and 2 generally depict left and right carotid arteries 30 and 32 as well as left and right femoral arteries 34 and 36 which bifurcate to superficial femoral and profunda arteries which are illustrative of arteries in a human vascular system. Finally, the FIGURES depict left 38 and right 40 brachial arteries in the figure's arms. A conventional percutaneous entry site for angioplasty, with stenting, is in a patient's common femoral artery at approximately location 42 shown in FIG. 1 or in a brachial arm artery at approximately site 44 also depicted in FIG. 1. Although a renal artery branch is specifically illustrated in the drawings the subject guide catheter with a distal marker balloon segment or balloon segments in addition to use in stenting renal arteries has particular application in other regions of a human circulatory system such as for example stenting an osteal or very proximal stenosis region in a left main coronary artery, a right coronary artery, arteries originating from the aortic arch, iliac arteries at a bifurcation of the abdominal aorta and superficial femoral arteries at a bifurcation of the common femoral arteries.

[0038] Referring now to FIG. 3 an aorta 20 is shown in broken away section at a junction location 46 with a renal artery 24, as an example of one specific application of the subject guide and marker catheter. A guide wire 48 is shown extending through the aorta 20 and a plaque stenosis 50. A wire mesh stent 52 surrounds a cylindrical high pressure stent balloon 54. High pressure as used in this disclosure means approximately nine to eighteen atmospheres of pressure. The stent lattice, scaffolding 52 and high pressure stent expansion balloon 54 extends through a guide catheter 56. The stent balloon is generally cylindrical and, is carried along the guide wire 48 to be operably directed by a physician toward the plaque stenotic segment 50 to be treated.

[0039] The guide catheter 56 is fitted at a distal end with an arcuate, low pressure, marker balloon segment(s) 58. This marker balloon segment(s) 58 is connected to an inflation tube that extends within the guide catheter 56 to a surgeon's access station. The marker balloon segment(s) 58 can be operably connected to a syringe containing radiopaque marker fluid for injection into the marker balloon segment(s) 58 with a relatively low operating pressure. As used in this description the term low operating pressure means one or two atmospheres of pressure which is low relative to the stent balloon pressure of nine to eighteen atmospheres or more.

[0040] In FIG. 4A a wire mesh stent 52 and interior, high pressure, expansion balloon 54 are shown advanced along the guide wire 48 and through the guide catheter 56 to a posture of partial insertion into a lesion zone of a plaque stenosis at a bifurcation junction of the renal artery 24 with the aorta 20.

[0041] FIG. 4B is an exploded bubble view of this initial insertion of the balloon stent 52. In this view, an arcuate marker balloon segment 58 is at least partially inflated with a low pressure radiopaque marker fluid at the distal end of the guide catheter 56. This inflation is performed as the guide catheter nears the renal artery bifurcation junction with the aorta 20.

[0042] FIG. 5A shows a guide catheter 56 and low pressure marker balloon 58 injected with radiopaque media and positioned adjacent an aorta renal artery bifurcation with a balloon stent 52 extended into a patient stenosis 50 at the bifurcation junction.

[0043] Bubble expansion image FIG. 5B illustrates a low pressure marker balloon segment 58 on a distal end of the guide catheter 56 at the renal bifurcation junction and a separate radiopaque band 60 (note FIGS. 9A and 9B), or a separate low pressure stent marker balloon segment at a proximal end of the high pressure stent balloon 54. When the two radiopaque markers 58 and 60 abut into a single radiopaque image the physician is visually alerted to a correct position of a proximal end of the stent at the aorta-renal artery bifurcation location and thus the stent 52 is in an accurate junction location for high pressure expansion of the stent balloon 54 to open the metal stent scaffolding and push the aorta—renal artery junction stenosis 50 outwardly.

[0044] Viewed in the direction of arrow “A” in FIG. 5B, FIG. 6 depicts one preferred embodiment of a single low pressure, arcuate, marker balloon 64 that preferably extends approximately three hundred and forty degrees around a distal end of guide catheter 56. The low pressure, marker balloon segment 64 has a small, low pressure line 66 that extends along or within the guide catheter 56 and is used to inflate the marker balloon segment 64. At a location exterior to a patient's vascular system a physician is able to inject low pressure (one or two atmospheres) radiopaque media into marker balloon 64 by injection from a hand syringe (not shown).

[0045] The marker balloon segment 64 preferably occupies an arcuate expanse of approximately three hundred and forty degrees so that there is a minimal gap of at least approximately twenty degrees past the marker balloon for passage of blood through the renal artery during a stenting procedure. Although three hundred and forty degrees is preferred for the arcuate extent of the marker balloon segment 64 a degree of operative advantage can be realized by the subject invention where the arcuate extent of the single marker balloon segment 64 shown in FIG. 6 is as little as forty five degrees.

[0046] FIG. 7 is a view similar to FIG. 6 but discloses an alternate preferred embodiment of the invention disclosing a low pressure marker balloon system including placement of two arcuate low pressure marker balloon segments 68 and 70 positioned in an opposing posture at a distal end of the guide catheter 56. This balanced arrangement of arcuate marker balloon segments, which can be independently inflated with marker fluid, enhances an ability to establish approximately coaxial placement of the opening of a guide catheter with a branch artery. In this embodiment each of the two balloon segments subtends an angle of at least one hundred degrees but less than one hundred and forty degrees and preferably one hundred and twenty degrees. The substantial open region, of approximately eighty to one hundred and sixty degrees, provides relatively unobstructed blood flow during a stenting procedure.

[0047] Each of the marker balloon arcuate segments is fitted with an independent thin tube 72 and 74 extending through the guide catheter for use in separately filling the low pressure marker balloons 68 and 70 respectively with a radiopaque fluid by using a syringe. The capacity to separately inflate each marker balloon enables a physician to selectively orient the end of the guide catheter 56 with respect to a branch artery as necessary or desirable to facilitate a normal or near normal positioning of the end of a guide catheter 56 with respect to placement at a desired branch artery.

[0048] FIG. 8 discloses yet another preferred embodiment of the invention including three approximately uniform arcuate marker balloons composed of low pressure balloon segments 76, 78 and 80 and independent fill lines 82, 84 and 86. This enables transmission of a low pressure radiopaque marker media via a syringe to the marker balloon segments at the distal end of the guide catheter 56. The marker balloon segments each extend peripherally around a distal end of the guide catheter at least approximately twenty degrees but less than one hundred degrees and preferably sixty degrees in arcuate extent around a distal end of the guide catheter 56. In this embodiment it is preferred that there is symmetric positioning of the marker balloon segments. This preferred marker balloon spacing concomitantly provides at least approximately sixty degrees of open space for blood flow during a stenting procedure and with three independent pressure zone capacity there is enhanced positioning capability of a distal end of a guide catheter 56 with respect to a branch artery by appropriate selection of pressure within each marker balloon segment.

[0049] FIGS. 9A-9C disclose a stenting procedure sequence in accordance with a preferred embodiment of the invention. In this, FIG. 9A depicts a guide wire 48 inserted through a stenosis 50 at a problem bifurcation junction of a renal artery 22 or 24 (note again FIGS. 1 and 2) with an aorta sidewall 20. In FIG. 9A the guide catheter 56 is shown advanced along the guide wire 48 until a low pressure, marker balloon 58 at a distal end of the guide catheter 56 abuts the aorta side wall 20 at the renal artery branch 22.

[0050] A syringe is used to inflate the low pressure marker balloon segment or segments 58 with a radiopaque marker media and the guide catheter 56 is positioned against the side wall of the aorta 20 at the renal artery bifurcation site. A balloon stent is slid over the guide wire 48 generally coaxially within the interior of the guide catheter 56 until a radiopaque stent marker 60 is positioned into the region of a bifurcation stenosis 50 as illustrated in FIG. 9A.

[0051] In FIG. 9B a physician is operably drawing the balloon stent 52 back along the guide wire 48 until a stent proximal marker 60, or low pressure balloon arcuate segment or segments, such as depicted in FIGS. 6-8, comes into register with a distal end of the guide catheter and the low pressure marker balloon segment or segments 58 at the distal end of the guide catheter 56. In this, the radiopaque image will become essentially one as the proximal end of the stent marker 60 slides into registry with the inflated marker balloon region 58 at a distal end of the guide catheter.

[0052] When the radiopaque marker 60 or low pressure marker balloon segment or segments at a proximal end of the balloon stent overlaps with the cover of the guide catheter marker balloon segment or segments 58 a physician accurately knows that a proximal end of the stent 52 is in a proper posture at a bifurcation location of, for example, the aorta—renal artery junction. At this point the interior stent balloon 54 is inflated with approximately nine to eighteen atmospheres of pressure to expand the wire stent scaffolding 52 as shown in FIG. 9C. Once expanded the plaque stenosis 50 is pushed outwardly allowing the damaged site to be enlarged internally to restore a flow of blood through the stenotic site.

[0053] The arcuate marker balloon segment gap(s) around the distal end of the guide catheter 56 enables blood perfusion to the diseased branch during accurate positioning of the stent at a bifurcation which may take minutes. The marker balloon segment gap(s) will also allow continuous measuring of blood pressure in the aorta by the guide catheter, when the marker balloon segment or segments are inflated.

[0054] When injecting radiopaque media through the guide catheter 56 radiopaque contrast media passes between the marker balloon segment(s) and into the side branch lumen thus providing a view of the downstream side vessel geometry and confirming a desired position of the marker balloon and stent relative to the main vessel and the side branch lumen.

[0055] In general the low pressure marker balloon(s) will cover varying degrees of the blood vessel opening, and the degree of coverage and marker balloon pressure may vary to allow matching the branching angle, such as when positioning the stent at a bifurcation that is less than 90 degrees. This might occur at the bifurcation of the abdominal aorta into the iliac arteries and the bifurcation of the common femoral arteries. In these instances the interventional physician, may prefer a marker balloon extending less than one hundred and eight degrees, in a way that the marker balloon will fall on the shoulder of the bifurcation, rather in the lumen of the branching vessel.

[0056] The low pressure marker balloon segment or segments outer cross sectional diameter is smaller the diameter of the main artery, to allow proper inflation, however, the cross sectional diameter is larger than a diameter of the side branch, in a way that prevents a prolapse into the side branch. In this connection, and as an example, the outside diameter of the marker balloon segment or segments should be between four and ten millimeters to butt against a junction location of an artery with the aorta side wall. The longitudinal extent of the catheter marker balloon segment or segments, when inflated, should reach but not unduly impinge upon the expanded stent.

[0057] The advantages provided by a low pressure marker balloon segment or segments mounted on a distal end of a guide catheter facilitates, for example, accurate positioning of a stent downstream of the aorta side wall and into a patient's branch vascular system. In this context the low pressure balloon market segment or segments permits both a flow of blood during a downstream stenting procedure and also a flow of radiopaque marker media to facilitate accurate placement of a stent at a downstream stenosis site. Although the structure of a low pressure marker balloon segment (or segments) are depicted, for example, in FIGS. 6-8, it will be appreciated by those skilled in the art that the physical size of the arcuate marker balloon segment, and arcuate marker balloon segments, in certain instances, may be selected to suit the anatomy of a patient of interest.

[0058] In describing the invention, reference has been made to preferred embodiments. Those skilled in the art however, and familiar with the disclosure of the subject invention, may recognize additions, deletions, substitutions, modifications and/or other changes which will fall within the scope of the invention as defined in the following claims.