WO2008099424A2 - A balloon catheter assembly and a method of use thereof - Google Patents

Abstract

The present invention relates to a balloon catheter assembly wherein at least one of the balloons of catheter assembly is highly compliant balloon capable of occluding a blood vessel or vessels at bifurcation by gaining a shape of the interior of the blood vessel or blood vessels at the bifurcation when inflated. The highly compliant balloon elastically expands at minimum pressure as less as less than 1.0 atm (101.325 KPa) thereby applying substantially less pressure on a blood vessel when inflated in vivo thereby may reduce distension of the blood vessel thereby potentially reduce damage and irritation to the contact areas of the blood vessel and minimizes abrasion and denuding of the healthy endothelial or endoluminal tissue of the blood vessel during method of treatment stenosis in a blood vessel or a bifurcated blood vessel.

Description

A BALLOON CATHETER ASSEMBLY AND A METHOD OF USE THEREOF.

FIELD OF INVENTION:

The present invention relates to a balloon catheter assembly that includes more than one balloon.

BACKGROUND OF THE INVENTION:

Obstructive vascular disease is the disruption of the normal flow of blood through the blood vessels, usually as a result of arterioscleroses, the accumulation of fatty plaque in the walls of arteries. Patients with arterioscleroses are at increased risk of stroke and heart attack.

Angioplasty is used to reopen a partially blocked blood vessel so that blood can flow through it again at a normal rate. Angioplasties were originally performed by dilating the blood vessel with introduction of larger and stiff catheters. The complications that resulted from this approach led the researchers to develop ways to open the vessel with smaller devices. As of now the catheters used to performing angioplasty contain the balloon that is inflated to widen the vessel, and stents to be deployed within the arteries to prevent restenosis and provide structural support for the vessel to maintain a clear pathway. Some catheters are equipped with spinning wires or drill tips to clean out the plaque.

Major difficulties involved in Angioplasty include but not limited to are the bifurcation lesion and distal embolisation. The difficulty subsists in the treatment of bifurcation lesion more particularly when the stenosis is at the ostium of one of the vessels. While dilating the said lesion using conventional balloon catheter, with the expansion of balloon such as dilation balloon, the plaque shifts in to the adjoining bifurcated branch of the vessel, which is otherwise in normal state. Such plaque shift may further lead to occlusion of the adjoining vessel /artery which is pathologically normal causing the detrimental effect to it. When a sizeable plaque shift occurs, the ostium of the adjoining vessel /artery can get occluded to such an extent that it does not allow the insertion of the guide wire and catheter for the treatment of such initially normal vessel / artery.

In order to prevent such occlusion of adjacent vessel/artery, the "kissing balloon" technique was developed. In this technique, two balloon dilation catheters are used parallely, one catheter extending into one branch of the bifurcation and the other one extending into the other branch. Balloons in both the branches, that is the stenosed branch and the adjacent normal branch are inflated to prevent the occlusion of the normal branch, which can become constricted. During such situation the proximal ends of the balloons "kiss" or touch in the common trunk vessel / artery. The disadvantage with such technique is that the effective diameter at the kissing proximal ends of the balloons may be too large causing the injury to the common vessel/artery.

To circumvent such problem catheter with the stepped balloon that has the proximal segment that is of a smaller diameter than the more distal segment is disclosed in the US Patent No. US 4,896,670. The smaller diameter proximal sections reduce the distension of the common artery and bifurcation where the kissing balloon technique is utilized. This type of catheter like the "kissing balloons" technique uses the two separate balloon catheters. The use of two single balloon catheters to treat arterial bifurcations has significant drawbacks. For example, the presence of two similar catheters exiting the proximal end of the guide catheter makes it difficult for a physician to manage both devices without becoming confused as to which catheter controls which balloon. Further, the presence of two balloon catheters creates a large device profile thereby limiting the amount of radiopaque dye, which can be injected into the vessel to allow the physician to view the bifurcation.

An improvement over use of two separate catheters is described in the international patent application WO 97/16217 of this type device a Y-shaped balloon is disposed at the distal end of a catheter which is inflated in a bifurcation to treat both passages simultaneously. However, the proposed device may not be practical due to challenges of manufacturing a Y-shaped balloon, attaching the same to a catheter shaft, and properly positioning it at a bifurcated blood vessel.

To overcome the problem associated with aforementioned devices, a bifurcated catheter assembly is described in United States Patent no. US 6,117,117. The bifurcated catheter assembly comprises a main catheter shaft having a stiffer proximal portion, and a pair of flexible branch catheters attached to the distal portion having balloon on each of the branch catheters. The balloons are held together to provide a low profile as the device is advanced over the tracking guide wire. Upon reaching the bifurcated vessel, the balloons are separated and are advanced over separate guide wires into separate branches of the bifurcated vessel. Such assembly uses two wires, two inflation kits and requires additional manpower to operate such multiple components. The maneuvering of such catheter and positioning of the balloon in the bifurcation will be difficult and challenging especially where the stenosis is just near the ostium. Besides both the balloon are semi compliant, which can cause injury to the normal vessel.

Another difficulty in 'angioplasty' is that the manipulation of balloon catheters in the arteries/vessels can dislodge embolic materials such as thrombotic material and/or plaque, which have the potential of being carried distally by the blood stream into the blood vessels thereby extending further damage. When this material travels downstream, it can cause serious complications. For example lose embolic material released within the ascending aorta, the arch, or carotid arteries may travel downstream to the brain, possibly causing stroke, which can lead to permanent injuries or even death of the patient.

The distal embolic protection devices currently available for use in angioplasty include different types of distal protection devices (DPD). One of them is a 'balloon catheter system' that temporarily occludes the vessel distal to the lesion during the intervention, thereby capturing and aspirating the atheromatous and thrombotic debris liberated by the lesion before it reaches the capillary bed.

Another distal embolic protection device is a 'filter system' that does not occlude blood flow; instead, it preserves flow but captures thrombi (as little as 100 urn) through small pores.

A number of filter devices utilize an expandable filter mounted on the angioplasty guide wire to facilitate entrapment of particles and removal. One of the devices available is Parodi Anti-Emboli System™, which is an example of a catheter occlusion device that establishes protection by reversing blood flow in the target vessel. However, the incomplete vessel occlusion with the filter devices may allow passage of debris through the holes of the filter devices. Besides after the saturation of debris within the filter, it may cause damage to the vessel. Also it necessitates use of another catheter to deploy and tale out the device. Further, it would be difficult and cumbersome to manipulate/remove filter device saturated with debris.

Another device is published in the international publication number WO 2006/032686 A1, for performing protected angioplasty and stenting of a patient's carotid bifurcation. This catheter system includes two catheters namely a rapid exchange angioplasty catheter and an occlusion balloon catheter. A releasable linking device holds the catheter system together as a unit. The occlusion balloon is inflated within the stent to occlude the carotid artery and to prevent any embolic debris from traveling downstream from the treatment site. The angioplasty balloon is inflated to dilate the stenosis and to complete the expansion of the stent. The angioplasty catheter is withdrawn and any potential embolic debris is aspirated out through the lumen of the guiding catheter. The occlusion balloon is deflated and the catheter system is withdrawn. Because of multiplicity of catheter units used, this catheter system is bulky, much complicated, and time consuming, which in turn keeps the artery closed for longer duration.

Further, it has been medically proven that the safety and protection of endothelium of the artery/vessels entail not to keep it occluded for longer duration. In this regard to minimize the complexities involved while manipulating balloon catheter system so as to reduce the inherent risks and duration of the operation and consequently to prevent damage of the pathologically healthy endothelium of the artery /vessel interacting with occlusion balloon is a cause of research.

In light of the foregoing, a need exists for an improved balloon catheter assembly that minimizes denuding of the healthy endothelial or endoluminal tissue due to abrasion and compression by the occlusion balloon when inflated, and which can be used to effectively treat bifurcations lesions and in distal embolic protection, which may contain provision for the aspiration too and useful in stent delivery and deployment. The balloon catheter assembly when used within the blood vessel should not tend to keep the artery/vessel occluded for longer duration.

SUMMARY OF THE INVENTION:

The present invention provides a balloon catheter assembly comprising a catheter body having a proximal portion and a distal portion, atleast two balloons capable of being inflated and deflated within a blood vessel, said balloons adapted spacedly on the distal portion of the catheter, and a lumen for each balloon for inflation and deflation wherein at least one of the balloons of catheter assembly is highly compliant balloon capable of occluding a blood vessel or vessels at bifurcation by gaining a shape of the interior of the blood vessel or blood vessels at the bifurcation when inflated.

According to the one embodiment of the invention, wall of said highly compliant balloon towards another balloon, is selectively and partially thickened so as to prevent substantial expansion of the highly compliant balloon towards another balloon and shifting of plaque.

According to the present invention, the catheter assembly comprises other balloon as a dilation balloon for dilating a plaque within the blood vessel. According to the present invention, the dilation balloon can be adapted before or after the highly compliant balloon.

According to the second embodiment of the present invention, distance between the balloons is at least 1 mm.

According to the third embodiment, a catheter portion form between the balloons comprises plurality of holes (ports) for aspirating blood and is connected by a separate passage or lumen within the catheter assembly.

The present invention also provides a method for treating stenosis in a blood vessel comprising steps of: inserting a balloon catheter assembly of the preferred embodiment comprising at least one highly compliant balloon and a dilation balloon; positioning the dilation balloon at the stenosis to be dilated; inflating the highly compliant balloon within the lumen of the artery/vessel to occlude the blood vessel; inflating the dilation balloon to dilate the stenosis; deflating the dilating balloon; deflating the occlusion balloon; removing the balloon catheter assembly; wherein the highly compliant balloon on inflating, adapts a shape of the interior of the vessel/artery and occludes the vessel portion by snuggly fitting to the interior wall of the vessel without applying substantial pressure on the vessel. According to an embodiment of the invention, to treat the stenosis near the bifurcation of the blood vessel, the highly compliant balloon advance across the bifurcation of the bifurcated vessel to occlude both the vessels at the bifurcation.

According to another embodiment of the invention, the method comprises a step of aspirating blood including debris of plaque after dilation through the holes provided over the catheter portion between the highly compliant balloon and the dilation balloon.

According to another embodiment of the invention, the balloon catheter assembly comprises two highly compliant balloons and a dilation balloon adapted between the highly compliant balloons to form an occluded portion within the blood vessel. The catheter portion between the balloons may have plurality of holes to aspirate the blood containing embolic debris.

The balloon catheter assembly of the present invention minimizes abrasion and denuding of the healthy endothelial or endoluminal tissue as the highly compliant balloon applies pressure as less as less than 1 atm over blood vessel.

BRIEF DESCRIPTION OF THE DRAWINGS ACCORDING TO THE INVENTION

Fig.1 is a side view of a balloon catheter assembly according to one of the preferred embodiment of the present invention;

Fig.2 is a side view of a balloon catheter assembly according to another preferred embodiment of the present invention;

Fig. 3 illustrates a sectional view of an blood vessel with atherosclerotic plaque showing a balloon catheter assembly shown in Fig 2 being advanced within the vessel with both the balloons inflated; Fig 4 illustrates a sectional view of a blood vessel bifurcation showing a balloon catheter assembly shown in Fig 1 being advanced within the blood vessel with both the balloons inflated.

DETAILED DESCRIPTION OF THE INVENTION:

The present invention relates to a balloon catheter assembly and method of treating the blood vessel using the same for all aspects of both angioplasty and stent delivery procedure. In most preferable term, the balloon catheter assembly of the present invention comprises a catheter body having a proximal portion and a distal portion, atleast two balloons capable of being inflated and deflated within a blood vessel, and a lumen for each balloon for inflation wherein atleast one of the balloon is a highly compliant balloon. According to the present invention, the balloons are adapted spacedly on the distal portion of the catheter. The balloons are attached at their proximal and distal ends to the catheter portions to form the fluid tight seal by employing known technique like attaching by use of adhesive, laser welding, solvent bonding, and heat sealing. Preferably, according to the present invention wall of said highly compliant balloon towards other balloon of the catheter assembly, is selectively and partially thickened so as to prevent expansion of the highly compliant balloon towards another balloon and plaque shifting.

The highly compliant balloon according to the present invention is made of a highly compliant material that elastically expands upon pressurization. The balloon is generally formed of material such as silicone, latex, polyisoprene rubber, polyethylene, polyolefin copolymer polyethylene terphathalate, nylon, polyurethanes or any other material suitable to make balloons of desired characteristics. Alternatively, balloons may be made from the same material used for making the tube. Balloon characteristics may be modified by addition of suitable plasticizers and stabilizers. According to the present invention, the highly compliant balloon preferably elastically expands at minimum pressure as less as less than 1.0 atm (101.325 KPa). The highly compliant balloon, on inflation, is capable of expanding within interior of the blood vessel and snuggly fit to the inner wall of blood vessel applying substantial less pressure on the vessel as after snuggly fitting within the blood vessel, due to its highly compliant nature, the highly compliant balloon even if inflated further expands in a direction of available space within interior of the blood vessel instead of applying pressure on the blood vessel. The dilation and highly compliant balloons used are of desired configurations and dimensions appropriate to serve the purpose.

According to the present invention, the highly compliant balloon is of any shape but more precisely dimension-wise perpendicular to the catheter body (refer Figs. 1 and 2) unlike the dilation balloon not parallel to the catheter body. When inflated the highly compliant balloon in vivo will expand adapt the same shape as that of the interior of the vessel/artery and occupy the interior of the vessel portion by snuggly fitting with the inner side of the vessel/artery and prevent the plaque shift and/or occlude the blood flow.

The dilation balloon is of typical shape generally known and used in the art in the balloon catheters that is of cylindrical or tubular shape running lengthwise parallel to the catheter body.

Referring to Fig 1, which shows a balloon catheter assembly (100) of one of the exemplary preferred embodiments of the present invention having proximal portion

(110) and a distal portion (120). The two balloons, namely a dilatation balloon (130) and a highly compliant balloon (140) for occlusion mounted spacedly on or near the distal end (122) of the distal portion (120). As shown in Fig 1 the highly compliant balloon (140) is mounted before the dilation balloon (130) on the distal portion (120) means the dilation balloon (130) is adapted between the distal end (122) and the highly compliant balloon (140). Alternatively, the highly compliant balloon can be mounted after the dilation balloon depending upon the need. The portion (142) of wall of the highly compliant balloon (140) towards the dilation balloon (130) is selectively and partially thickened to prevent expansion of the highly compliant balloon (140) towards the dilation balloon (130) and shifting of a plaque.

Referring to Fig 3, which shows a catheter assembly (200) of another exemplary embodiment of the present invention similar to that of the Fig 1 comprising a dilation balloon (230) and a highly compliant balloon (240) on the distal portion

(220) wherein a catheter portion (260) between the highly compliant balloon (240) and dilation balloon (230) has plurality holes (250) for aspiration. As shown in the

Fig 2 the highly compliant balloon (240) is adapted after the dilation balloon (230) i.e. between the dilation balloon (230) and a distal end (222) of the distal portion.

According to the present invention two highly compliant balloons can be adapted on the distal portion of the assembly along with a dilation balloon adapted between the highly compliant balloons. One or both catheter portions between these balloons can be provided with plurality of holes for blood aspiration.

According to the present invention, the distance between the two balloons that is length of the catheter portion between the two balloons is depends upon the requirement and preferably atleast 1 mm. The catheter assembly may have an arrangement to adjust the distance between the balloons.

According to the present invention, each balloon is connected to a separate lumen (not shown) extending from the proximal portion of the catheter assembly to inflate or deflate the balloon. The catheter portion between the balloons as shown in Fig 2 also has a separate lumen extending from the proximal portion of the catheter assembly. The proximal portion comprises Y connector for each lumen to act as inlet/outlet ports for inflation/deflation device such a syringe (not shown) to deliver or withdraw the inflating agent and/or for aspiration of the blood with thrombotic fluid. As shown in Figs. 1 , the proximal portion (110) comprises at least two Y- connectors with side ports (112 and 114) for inflating or deflating the dilation balloon (130) and the highly compliant balloon (140) separately. In Fig 2, the proximal portion (210) comprises at least three Y-connectors with side ports (212, 214 and 216) connected with the lumens of the catheter assembly for inflating or deflating the two balloons and for aspirating the blood with thrombotic fluid separately. Alternately, the proximal portion may have in place of or in addition to Y connectors, manifold (not shown) to serve such purposes. The manifold to be used can be conventional manifold or can be designed suitably to meet the requirements.

Further, each catheter assembly of the present invention has an arrangement (not shown) of guide wire (not shown) for inserting the catheter assembly at desired place. The lumen of the guide wire generally extends centrally from the proximal end to the distal end. The catheter assembly of the present invention may use rapid exchange technique for guide wire for inserting the catheter assembly in the blood vessel.

The lumens (not shown) in the catheter assembly are arranged in any suitable configuration for aiding ease in maneuvering and/or construction.

The proximal portion (110 and 210) is of sufficient length as desired. Preferably the proximal portion is sufficiently longitudinally flexible so that it can bend suitably to adapt to the vascular /arterial curvature. The proximal portion of the catheter assembly can be made of known material using known techniques such as polymeric materials like polyethylene, polystyrene, or nylons or metals like stainless steel or shape memory alloys such as nickel titanium blends. The surface of the tube may be coated with a polymer jacket made from materials including nylon, polyethylene, polyethyl ether ketone, co-polyester-elastomer, or the like, to provide lubricity. The distal portion of the catheter body is of slender and identical hollow tubular form as of proximal portion and made from material providing higher flexibility to follow the vascular /arterial curvature comfortably without having any undesirable effect on the endothelial tissues, preferably it can be made of suitable polymeric material. The distal portion is of desirable length and dimensions of the outer and inner diameter and wall thickness.

For visualization while using and judging the position of balloons, a marker band (not shown) made of radiopaque material is attached to the catheter assembly between the proximal and distal ends of balloons.

The balloon catheter assembly as shown in Figs. 1 and 2 may be used in angioplasty and/or stenting to prevent plaque shift more particularly in cases involving bifurcation lesion, where the stenosis is at the ostium of one of the vessels as shown in Fig 4.

Referring to Fig 3, wherein a stenosis (52) to be treated is formed in a single vessel (50). The catheter assembly (200) shown in Fig 2 is advanced in the blood vessel

(50) with the help of guide wire through the body lumen as per the requirement and the dilation balloon is positioned across the stenosis (52). For better understanding of the invention, a part of the distal portion of the catheter assembly as shown in

Fig 2 representing the invention is shown in Fig 3. According to the present invention, the highly compliant balloon (240) is inflated first to occlude the vessel

(50). As the highly compliant balloon (240) has thickened wall towards the dilation balloon (230), the non-thickened portion of the highly compliant balloon (240) gets inflated first resulting in the inflation of the highly compliant balloon substantially less towards the dilation balloon (230) thereby preventing the expansion substantially towards the dilation balloon (230). The highly compliant balloon (240), on inflation, expands within interior of the blood vessel and snuggly fits to the inner wall of blood vessel thereby occluding the blood vessel and on inflation of the dilation balloon, prevent shifting of plaque and traveling of any embolic debris from the treatment site. Due to the high compliant property and requirement of less pressure as less than 1 atm (101.325 KPa) to inflate, the highly compliant balloon even if inflated further after snuggly fitting within the blood vessel, the highly compliant balloon expands in a direction of available space within interior of the blood vessel instead of applying pressure on the blood vessel. Thus the highly compliant balloon of the present invention may reduce distension of the blood vessel thereby potentially reduce damage and irritation to the contact areas of the blood vessel and minimizes abrasion and denuding of the healthy endothelial or endoluminal tissue of the blood vessel. After treatment, the dilation balloon is deflated and blood is aspirated through the plurality of the holes along with the embolic debris before the highly compliant balloon is to be deflated. After removal of blood containing debris, the highly compliant balloon is deflated and the assembly is removed.

In Fig 4 the stenosis (62) to be treated is formed near the bifurcation in one (60A) of the vessels (6OA, 60B) of the bifurcated vessels (60). For treating stenosis, according to the method of the present invention, the catheter assembly (100) shown in Fig 1 is advanced in a blood vessel (60) with the help of guide wire through the body lumen as per the requirement and the dilation balloon is positioned across the stenosis (62). For better understanding of the invention, a part of the distal portion of the catheter assembly as shown in Fig 1 representing the invention is shown in Fig 4. The catheter assembly is selected in such a way that the highly compliant balloon is positioned across the bifurcation in the bifurcated vessel to occlude both vessels that is the distance between the highly compliant balloon depends upon the distance of the stenosis from the point of bifurcation. Alternatively, the catheter assembly may have arrangement to adjust the distance between the dilation balloon and the highly compliant balloon. According toe the present invention, the highly compliant balloon (140) is inflated first to occlude the vessel (6OA and/or 60B). As the highly compliant balloon (140) has thickened wall towards the dilation balloon (130), the non-thickened part of the highly balloon gets inflated first resulting in less inflation of the highly compliant balloon towards the dilation balloon thereby preventing the expansion substantially towards the dilation balloon (130). The highly compliant balloon (140), on inflation, expands within interior of the blood vessel and snuggly fit with the inner wall of blood vessel (60A) as shown in Fig 4. The highly compliant balloon, on further inflation, due to the compliant property, start inflating in the space available thereby snugly fitting with the inner wall of the another vessel (60B) at the opening as shown in Fig 4 thereby occluding the vessels at the bifurcation point and preventing shifting of plaque from traveling from one vessel to another vessel when dilation balloon is inflated and also prevent traveling of any embolic debris. Due to the high compliant property and requirement of less pressure to inflate as less as less than 1atm (101.325 KPa), the highly compliant balloon even inflated further, after snuggly fitting within the blood vessel, expands in the direction of available space within interior of the blood vessel instead of applying pressure on the blood vessel. Thus, the highly compliant balloon of the present invention may reduce distension of the blood vessel thereby potentially reduce damage and irritation to the contact areas of the blood vessel and minimizes abrasion and denuding of the healthy endothelial or endoluminal tissue of the blood vessel. After treatment, the highly compliant balloon is deflated and the assembly is removed.

According to the present invention a catheter assembly comprising two highly complaint balloons and a dilation balloon adapted between the highly compliant balloons can be used to treat the stenosis at or on bifurcation of the bifurcated vessels. According to the requirement, proximal or distal stenosis, the respective highly balloon can be inflated to occlude the blood vessel to prevent plaque shifting and/or to aspirate the blood containing the debris.

For angioplasty, an angioplasty stent can be adapted over the dilation balloon of the catheter assembly of the present invention to deliver at the stenosis. While the present invention has been described herein with respect to the various exemplary embodiments, it will be apparent to one of the ordinary skill in the art that many modifications, improvements and sub combinations of the various embodiments, adaptations and variations can be made to the invention without departing from the spirit and the scope thereof.

As shown in Figures 1 and 2, the balloon catheter assemblies are of exemplary in nature only and catheters of other designs, configurations and constructions material may also be employed in this invention appropriately. The person ordinary skilled in the art is generally aware of such catheters.

Claims

1. A balloon catheter assembly, comprising:

a catheter body having a proximal portion and a distal portion;

atleast two balloons capable of being inflated and deflated within a blood vessel, said balloons adapted spacedly on the distal portion of the catheter; and

a lumen for each balloon for inflation and deflation;

wherein at least one of the balloons is highly compliant balloon capable of occluding a blood vessel or vessels at bifurcation by gaining a shape of the interior of the blood vessel or blood vessels at the bifurcation when inflated in vivo.

2. A balloon catheter assembly as claimed in claim 1 wherein the other balloon is a dilation balloon for dilating a plaque within the blood vessel.

3. A balloon catheter assembly as claimed in claim 1 wherein the balloons are spaced on the catheter assembly at a distance of at least 1 mm from each other.

4. A balloon catheter assembly as claimed in claim 1 or 4 wherein a catheter portion between the balloons comprises plurality of holes for aspirating blood containing embolic debris with a separate passage within the catheter assembly.

5. A balloon catheter assembly as claimed in claim 1 or 2 wherein wall of said highly compliant balloon, towards another balloon, is selectively and partially thickened so as to prevent substantial expansion of the highly compliant balloon towards the other balloon and shifting of the plaque.

6. A balloon catheter assembly as claimed in claim 1 or 5 wherein the highly compliant balloon elastically expands at minimum pressure as less as less than 1.0 atm (101.325 KPa) thereby applying substantially less pressure on a blood vessel when inflated in vivo.

7. A balloon catheter assembly as claimed in one of the preceding claims wherein said highly compliant balloon is made of highly complaint material such as silicone, latex, polyisoprene rubber, polyethylene, polyolefin copolymer polyethylene terphathalate, nylon, polyurethanes or any other material suitable to make balloons of highly complaint nature.

8. A catheter assembly as claimed in claim 2 wherein said compliant balloon is adapted before or after the dilation balloon on the distal portion.

9. A catheter assembly as claimed in claim 2 wherein an angioplasty stent can be adapted on the dilation balloon.

10. A balloon catheter assembly as claimed in one of the preceding claims wherein said catheter comprises two highly compliant balloons and a dilation balloon adapted between the highly compliant balloons.

11. A highly compliant balloon for a balloon catheter assembly made of a highly compliant material wherein said balloon elastically expands at minimum pressure as less as less than 1.0 atm (101.325 KPa) thereby applying substantially less pressure on a blood vessel when inflated in vivo.

12. The highly compliant balloon as claimed in claim 11 wherein wall of said highly compliant balloon, towards another balloon of the catheter assembly, is selectively and partially thickened so as to prevent expansion of the highly compliant balloon towards another balloon and shifting of plaque.

13. The highly compliant balloon as claimed in claim 11 wherein the balloon is made of highly compliant material such as silicone, latex, polyisoprene rubber, polyethylene, polyolefin copolymer polyethylene terphathalate, nylon, polyurethanes or any other material suitable to make balloons of desired characteristics.

14. A method for treating stenosis in a blood vessel comprising steps of :

inserting a balloon catheter assembly comprising at least one highly compliant balloon and a dilation balloon as claimed in one of the claims 1-9 in the blood vessel;

positioning the dilation balloon across the stenosis to be dilated;

inflating the highly compliant balloon within the blood vessel to occlude the blood vessel;

inflating the dilation balloon to dilate the stenosis;

deflating the dilating balloon;

deflating the highly compliant balloon;

removing the balloon catheter assembly;

wherein the highly compliant balloon on inflating, adapts a shape of the interior of the vessel/artery and occludes the vessel portion by snuggly fitting to the interior wall of the vessel without applying substantial pressure on the vessel.

15. A method as claimed in claim 14 further comprises steps of aspirating blood including debris of plaque through the holes provided over the catheter portion between the highly compliant balloon and the dilation balloon before deflation of the highly compliant balloon.

16. A method as claimed in claim 14 wherein stenosis is near the bifurcation of the bifurcated vessel.

17. A method as claimed in claim 14 wherein the method comprises steps of selecting the distance between the highly compliant balloon and the dilation balloon before advancing the catheter assembly in the blood vessel so as to position the highly compliant balloon across the bifurcation in the bifurcated vessel to occlude both vessels.

18. A method as claimed in one of the claims 14 to 18 wherein the balloon catheter assembly comprises two highly compliant balloons and a dilation balloon adapted between the highly compliant balloons wherein one of the highly compliant balloons inflated as per the requirement.