A valvuloplasty balloon catheter (100) is disclosed. The valvuloplasty balloon catheter (100) comprises of an inflatable member (40) having anchor shaped ends and a tubular member (50). The tubular member (50) comprises of a proximal section (50a), a distal section (50b) and a middle section (50c). The middle section (50c) includes a proximal middle portion (50c1), a distal middle portion (50c2) and an intermediate portion (50c3). The proximal middle portion (50c1) and the distal middle portion (50c2) includes a plurality of closed cells (54). At least one of the proximal section (50a) or the distal section (50b) includes a plurality of first struts (52) being anchor shaped. The plurality of closed cells (54) includes one or more zig-zag elements being placed over tapered end of the inflatable member (40) thereby allowing uniform and smooth expansion of the tubular member (50). The intermediate portion 50c3 includes a plurality of s-shaped links.

FIELD OF INVENTION

The present invention relates to a catheter for medical devices. More specifically, the present invention relates to a valvuloplasty balloon catheter.

BACKGROUND

Stenosis of an aortic or other cardiac valve occurs when a valve annulus narrows restricting the flow of blood through the valve when open. In order to treat such condition of valves, valvuloplasty proves to be a promising therapeutic procedure.

Valvuloplasty corresponds to widening of a stenotic valve using a balloon catheter. In valvuloplasty procedure, an operator inserts a hollow tube (catheter) into a blood vessel in the arm/groin of a patient and advances it through the aorta into the heart. Once the catheter reaches the treatment site, a balloon is expanded until the native leaflets of the valve are pushed open. Once the valve is open, the balloon as well as the catheter is removed.

However, treating blood vessels using valvuloplasty is associated with multiple shortcomings. One of the major obstacles is re-stenosis i.e. reoccurrence of stenosis.

Further, lack of effectiveness of pre-dilation in few patients has been observed. This is due to the fact that the radial pressure applied by the balloon is not always directed symmetrically, and the balloon can often slip from their original placement within the valve annulus. Both these circumstances limit the effectiveness of conventional valvuloplasty therapy.

Recently, scoring elements have been introduced for overcoming the above problems effectively. These are stent like structures mounted over the balloon which expand along with the balloon to remove calcified tissues from the implantation site at the time of pre-dilation. However, the conventional scoring elements are not bonded to the catheter properly and have reduced flexibility leading to greater force requirement when advance through torturous anatomy. Moreover, the conventional scoring elements may impart injury and trauma to the vessel wall during delivering, retraction and expansion in the vessel. Further, the existing structures of the scoring elements detach easily after multiple cycles of balloon inflation/deflation.

Therefore, there arises a requirement of a delivery device for an implant which overcomes the aforementioned challenges associated with the conventional delivery systems.

SUMMARY

The present invention relates to a valvuloplasty balloon catheter. The said catheter includes an inflatable member having anchor shaped ends. A tubular member is mounted over the inflatable member. The tubular member includes a proximal end and a distal end. The tubular member includes a proximal section which is disposed towards the proximal end, a distal section which is disposed towards the distal end and a middle section disposed there between. At least one of the proximal section or the distal section includes a plurality of first struts, which are anchor shaped. The middle section includes a proximal middle portion, a distal middle portion, and an intermediate portion connecting the proximal middle portion and the distal middle portion. The intermediate portion includes a plurality of s-shaped links.

The foregoing features and other features as well as the advantages of the invention will become more apparent from the following detailed description, which proceeds with reference to the accompanying figures.

DETAILED DESCRIPTION OF THE DRAWINGS

Prior to describing the invention in detail, definitions of certain words or phrases used throughout this patent document will be defined: the terms “include” and “comprise”, as well as derivatives thereof, mean inclusion without limitation; the term “or” is inclusive, meaning and/or; the phrases “coupled with” and “associated therewith”, as well as derivatives thereof, may mean to include, be included within, interconnect with, contain, be contained within, connect to or with, couple to or with, be communicable with, cooperate with, interleave, juxtapose, be proximate to, be bound to or with, have a property of, or the like; Definitions of certain words and phrases are provided throughout this patent document, and those of ordinary skill in the art will understand that such definitions apply in many, if not most, instances to prior as well as future uses of such defined words and phrases.

Further, descriptions and disclosures provided in association with one particular embodiment are not limited to that embodiment, and may be applied to any embodiment disclosed herein. Moreover, for the sake of simplicity, the attached figures may not show the various ways in which the disclosed system and apparatus can be used in combination with other systems, and apparatuses.

Furthermore, the described features, advantages, and characteristics of the embodiments may be combined in any suitable manner. One skilled in the relevant art will recognize that the embodiments may be practiced without one or more of the specific features or advantages of a particular embodiment. In other instances, additional features and advantages may be recognized in certain embodiments that may not be present in all embodiments. These features and advantages of the embodiments will become more fully apparent from the following description and apportioned claims, or may be learned by the practice of embodiments as set forth hereinafter.

In accordance with the present disclosure, a balloon catheter is disclosed. The balloon catheter of the present invention is used for pre-dilatation of a native stenotic valve prior to implantation of a heart valve. The balloon catheter may also be used for pre-dilatation in any coronary and/or peripheral artery.

The balloon catheter of the present invention includes a tubular member (tubular element) mounted over an outer surface of a balloon (or any other equivalent expandable structure). The tubular member of the present invention is expanded upon expansion of the balloon thereby leading to breakage of calcified tissues at an implantation site.

The tubular member includes three major sections i.e. a proximal section, a middle section and a distal section. The proximal and the distal sections include struts that are anchor shaped and hence, allow better attachment of the tubular member with the balloon. The middle section is provided with a plurality of closed cells having zig-zag elements. The closed cell structure in the middle section allows better expansion of the tubular member once the balloon is inflated. The zig-zag elements also help to increase the length of the tubular member during balloon inflation. The middle section of the tubular member is provided with at least one marker for better radio-opacity of the tubular member while fluoroscopic imaging. The aforesaid tubular member maintains its shape even if it is crimped for a long time and/or undergoes multiple inflation-deflation cycles. Further, the middle section includes a proximal middle portion, a distal middle portion, and an intermediate portion connecting the proximal middle portion and the distal middle portion. The intermediate portion includes a plurality of s-shaped links which provide enhanced flexibility and ease in advancement through aortic arc, thereby avoiding any injury to the vessel.

Referring to figures,FIG.1depicts the balloon catheter (or valvuloplasty balloon catheter)100of the present invention. As mentioned earlier, the balloon catheter100of the present invention is used for pre-dilation of a native stenotic valve. The balloon catheter100of the present invention may be used to treat stenosis of without limitation, aortic valve, pulmonary valve and bicuspid valve. Moreover, the balloon catheter100of the present invention may be used for valve in valve (ViV) procedure and/or for coarctation of aorta before stent placement.

The pre-dilation of the stenotic valve might create debris which when released into the bloodstream may cause blockages in smaller vessels. Hence, the balloon catheter100of the present invention may be provided with an embolic filter200as shown inFIG.1a. The embolic filter200may be structured to capture as well as remove debris during valvuloplasty procedure. The embolic filter200may be a self-expanding filter attached with the balloon catheter100at a pre-defined location. In an embodiment, the embolic filter200is placed before the aortic arch to avoid any emboli to go further in the bloodstream.

The balloon catheter100may include a pre-defined diameter. In an embodiment, the diameter of the balloon catheter100is one of, 14 mm, 16 mm, 18 mm, 20 mm, 23 mm or 25 mm. The length of the balloon catheter100may be in a range of 1200 mm to 1400 mm. In an embodiment, the length of the balloon catheter100is 1300 mm.

The balloon catheter100of the present invention includes various components such as, without limitation, one or more of, a catheter tubing10, a hub20, a soft tip30, an inflatable member40, a tubular member50and at least two couplers60a,60b.

The catheter tubing10of the balloon catheter100may be a conventional structure which is utilized to mount the other components of the balloon catheter100. The catheter tubing10may include pre-defined dimensions and shape. The catheter tubing10may include a proximal end10aand a distal end10b. The proximal end10aof the catheter tubing10may be coupled to the hub20of the balloon catheter100. The distal end10bof the catheter tubing10may be coupled to the soft tip30.

The hub20and the soft tip30of the balloon catheter100may be conventional structures. The hub20may include various ports such as guide wire port, inflation port, etc.

The soft tip30may be equivalent to any atraumatic tip known in the art, which is configured to guide the balloon catheter100through the body lumen while avoiding any perforation in the body lumen.

The inflatable member40for example a balloon, as shown inFIG.1is mounted over the catheter tubing10towards its distal end10b. The inflatable member40of the balloon catheter100may be an expandable structure. The inflatable member40may be made of a pre-defined polymeric material having good elasticity and which is capable of enduring high inflation pressures during the valve expansion. The material includes, without limitation, nylon, polyether block amide, polyethene terephthalate (PET), polyamide, polyurethanes, polyvinyl chloride, polyethylene, etc. In an embodiment, the inflatable member40is made from polyamide resins.

The inflatable member40may be made of a single layer or may include multiple layers. In an embodiment, the inflatable member40is a single layered structure. The rated burst pressure of the inflatable member40may range from 5 atm to 10 atm. In an embodiment, the rated burst pressure of the inflatable member40is 6 atm.

The inflatable member40includes a proximal end40aand a distal end40b. The distal end40bof the inflatable member40is disposed towards the distal end10bof the catheter tubing10. The proximal end40ais placed opposite to the distal end40b. The inflatable member40tapers towards its ends to connect with the catheter tubing10at the proximal end40aand a distal end40bas shown inFIG.1.

Though the present invention is described with the help of a balloon, however, any other equivalent inflatable member40capable of being inflated and deflated is also within the scope of the present invention.

The tubular member50is attached to or mounted over the catheter tubing10. The tubular member50may be made of a conventional metallic material(s) which includes without limitation, stainless steel, cobalt-chromium, nitinol, etc. In an embodiment of the present invention, the tubular member50is made of nitinol owing to its self-expanding and super-elastic properties. The tubular member50includes a pre-defined structure which helps to break the calcified tissues. The tubular member50may be fabricated using a conventional method. In an embodiment, the tubular member50is formed by laser cutting a hollow cylindrical tube.

The inner diameter of the tubular member50may range from 2.5 mm to 3.5 mm. In an embodiment, the inner diameter of tubular member50is 3.01 mm. The outer diameter of tubular member50may range from 3.0 mm to 4.0 mm. In an embodiment, the outer diameter of tubular member50is 3.61 mm.

As shown inFIG.1, the tubular member50includes a plurality of closed cells54. The tubular member50may include elongated cells that expand with the inflatable member40of the balloon catheter100.

As shown inFIG.2more clearly, the tubular member50includes a proximal end501and a distal end502. Further, as depicted inFIG.2, the tubular member50includes three sections i.e. a proximal section50a, a distal section50band a middle section50cdisposed there between. The proximal section50ais disposed towards the proximal end501of the tubular member50while the distal section50bis disposed towards the distal end502. The soft tip30is coupled to the distal section50bof the tubular member50. The catheter tubing10is coupled to the proximal section50aof the tubular member50.

The aforesaid coupling of the tubular member50of the present invention may be mediated with the help of the couplers60a,60b. The couplers60a,60bcan be for example, sleeves, tubes, rings (O shape, C shape or any other shape), stoppers etc. In an embodiment, the tubular member50is coupled via welding technique or combination of welding & adhesive bonding.

The structure of the proximal section50aand the distal section50bmay be same or different. In an embodiment, the proximal section50aand the distal section50bis same. As shown inFIG.2and more clearly inFIG.2a, the proximal section50aand the distal section50binclude a plurality of first struts52. The number of first struts52may vary depending on the diameter of the inflatable member40. The number of first struts52may range between 02 to 10. In an embodiment, the number of first struts52is six.

The first struts52may include a pre-defined shape. The shape of the first struts52may be any conventional shape. Such shapes may include, without limitation, spear shape, triangular shape, linear leaf shape, lanceolate leaf shape, anchor shape etc. In an exemplary embodiment as depicted inFIG.2a, the first struts52are in the form of spear shaped structures. The said shape of the first struts52help to hold the tubular member50on to the catheter tubing10firmly during the inflation as well as the deflation of the inflatable member40.

The first struts52may be in the form of solid structures as represented inFIG.2aor may include a cut-out as represented inFIG.2b. The cut-out structure of the first struts52adds extra flexibility and smoothness to the tubular member50which in turn helps in its bonding with the soft tip30/the catheter tubing10via the couplers60a,60b. Further, the side edges of the first struts52may be uniform i.e. straight or non-uniform i.e. having a sine-wave shape, a peak-valley shape, a zig-zag shape, etc.

In another embodiment as depicted inFIG.2c, each of the first struts52is connected to an adjacently placed first strut52with the help of a curved connector ‘c’. The utilization of such connectors reduces chance of slippage over the balloon surface.

In yet another embodiment, the first struts52are in the form of the anchor shape as depicted inFIG.2c1. The said shape of the first struts52has smooth edges which help to minimize and/or avoid trauma to the vessel wall during retraction and/or expansion of the tubular member50post deflation inside the blood vessel. Further, the anchor shape of the first struts52imparts strong grip to the couplers60aand60bon the distal end502and proximal end501of the tubular member50, thereby providing robust attachment of the tubular member50on the catheter tubing10. Strong attachment of the tubular member50over the catheter tubing10prevents removal of the tubular member50during multiple cycles of balloon and inflation and deflation process.

The thickness of the first struts52may be in a range of 0.10 mm to 0.50 mm. In an embodiment, the thickness is 0.30 mm.

The first struts52include a pre-defined length and width which assist to fix the position of the tubular member50within the couplers60a,60b(as clearly shown inFIG.2d) thereby helping the tubular member50to withstand high bond strength. The length of the first struts52may range from 2 mm to 16 mm. In an embodiment, the length of each first strut52is 6 mm-12 mm. The first struts52having a length in the aforesaid range enhance the flexibility of the tubular member50due to the presence of less material of construction. Also, owing to the use of struts having reduced width, more number of struts is required which in turn increases the radial strength of the tubular member50.

The middle section50cextends between the proximal section50aand the distal section50b. The total length of the middle section50cmay be in a range of 50 mm to 70 mm. In an embodiment, the total length of the middle section50cis 62 mm.

As shown inFIG.2e, the middle section50cincludes three sections i.e. a proximal middle portion50c1, a distal middle portion50c2and an intermediate portion50c3connecting the proximal middle portion50c1and the distal middle portion50c2. The proximal middle portion50c1is disposed towards the proximal section50awhile the distal middle portion50c2is disposed towards the distal section50b.

The proximal middle portion50c1and the distal middle portion50c2may contain one or more rows having large cell assemblies. The said cells may either be open cells or closed cells. In an embodiment, the proximal middle portion50c1and the distal middle portion50c2include a plurality of closed cells having a predefined shape.

The closed cells of the proximal middle portion50c1and the distal middle portion50c2may include same or differently structured closed cells. As represented inFIG.2e, the closed cells of the proximal middle portion50c1and the distal middle portion50c2are same and are referred as closed cells54. The structure of the closed cell54is clearly represented inFIG.2e/2f.

Each closed cell54may include a predefined shape formed by a plurality of struts for example, hexagonal, rhombus, diamond, etc. Each of the closed cells54of the present invention includes zig-zag elements. The portion of the closed cell54having zig-zag elements is mounted over the tapered portion of the inflatable member40in a tapered configuration. The presence of zig-zag shaped elements help to remove the plaque or calcified portion during the expansion of inflatable member40. The zig-zag elements of the present invention help to adjust the length of the tubular member50so that the tubular member50smoothly and uniformly expands along with the inflatable member40.

In an exemplary embodiment of the present invention, the closed cell54is a rhombus shaped cell having four struts. In an embodiment shown inFIG.2f, each closed cell54includes a first pair of struts54aand a second pair of struts54b. Each first pair of struts54ais connected to each other at a first peak ‘p1’. The first peak ‘p1’ may be in contact with the first strut52and help to connect the first row of the proximal middle portion50c1to the first struts52of the proximal section/distal section50a/50b. Each second pair of struts54bmay be connected with each other at a second peak ‘p2’. The second peak ‘p2’ may be in contact with the intermediate portion50c3(described below). The first pair of struts54amay be connected to the second pair of struts54bat a peak ‘p3’. The peak ‘p3’ allows each closed cell54to connect with the adjacent closed cell54via a link ‘s’ thereby forming a circumferential row of closed cells54. The link ‘s’ may be straight link. The length of the links ‘s’ may range from 0.2 mm to 0.8 mm. In an embodiment, the length of each link ‘s’ is 0.47 mm.

The struts of the closed cell54(namely, the first pair of struts54aand/or the second pair of struts54b) may be identical in structure or may include different structures.

In an embodiment, the first pair of struts54aand/or the second pair of struts54binclude at least a portion having zig-zag elements. In an embodiment, the first pair of struts54aand/or the second pair of struts54bmay be entirely zig-zag in shape (not shown). Alternately, each strut of the first pair of struts54aand/or the second pair of struts54bmay include a zig-zag element and a first element a1thereby forming a hybrid structure. The first element a1may include any shape such as without limitation, a straight shape, a spline shape, a semicircular shape, etc. In an embodiment as shown inFIG.2f, the first element a1is straight shaped. The length of the zig-zag element and the length of the first element a1may have a pre-defined ratio. The pre-defined ratio may range between 8:2 to 2:8 respectively for zig-zag element and first element a1with respect to length. In an embodiment, the pre-defined ratio is 6:4 for zig-zag element and first element a1respectively.

Each zig-zag element may include a plurality of crests and troughs. The number of crests and troughs may range from two to twelve. In an embodiment, the number of crests and troughs are six. The length of zig-zag element plays an important role in the sizing of the tubular member50. The length of the zig-zag element may range from 8.5 mm to 10.5 mm. In an embodiment, the length is 9.69 mm. Such length leads to accurate expansion of tubular member50when inflated.

The length of the first element a1may range between 5.0 mm to 7.0 mm. In an embodiment, the length of the first element a1is 6.16 mm.

Each strut of the second pair of struts54bmay be straight. However, it should be noted that other shapes of such struts are also within the scope of the present invention. Each of the second pair of struts54bincludes a length ranging from 10 mm to 14 mm. In an embodiment, the length is 11.90 mm.

The total length of each closed cell54(in compressed stage) may range between 23.5 mm to 32.5 mm. In an embodiment, the total length of each closed cell54is 27.75 mm.

The intermediate portion50c3includes a plurality of marker links56as shown inFIG.2g. The number of marker links56may be dependent upon the number of closed cells54. The number of marker links56may range between 2 to 8. In an embodiment, the intermediate portion50c3includes six marker links56. The marker links56help to connect the closed cells54of the proximal middle portion50c1with the closed cell54of the distal middle portion50c2via peaks ‘p2’ as depicted inFIG.2e.

The total length of the marker link56may range from 3 mm to 8 mm. In an embodiment, the length is 5 mm. The marker link56may include a plurality of markers56a. In an embodiment, each marker link56includes a single marker56a. The marker56amay be disposed at the center of marker link56. The marker56amay be made of a conventional radiopaque material such as without limitation, platinum, tantalum, platinum tungsten, platinum iridium, gold, etc. In an embodiment, the present invention includes markers56amade from tantalum and having a round shape. The diameter of the marker56amay range from 0.25 mm to 0.45 mm. In an embodiment, the diameter of the marker56ais 0.35 mm.

In another embodiment, the intermediate portion50c3includes a s-shaped connecting link56as depicted inFIG.2g1. The presence of the S shaped link in the intermediate portion50c3imparts enhanced flexibility, reduces stress at the proximal end501and the distal end502and helps in withstanding high pressure to the tubular member50. Moreover, the s-shaped links help in easy advancement of the tubular member50through the aortic arc owing to enhanced flexibility and thus avoids vessel injury.

Further, the presence of the S-shaped links56helps to increase inflation and deflation cycles of the inflatable member40due to uniform distribution of the stress on the tubular member50. Owing to uniform stress distribution, the tubular member50can withstand high pressure without detachment of the couplers60aand60bwith the catheter tubing10.

Hence, as per the above exemplary embodiments, the structure of the tubular member50is in the form of a plurality of columns ‘CS’ which are replicated radially to form the complete structure of the tubular member50. Each column includes a first strut52of the proximal section50a, a closed cell54of the proximal middle section50c1, a marker link56of the intermediate portion50c3, a closed cell54of the distal middle portion50c2and a first strut52of the distal section50b(in the aforesaid sequence). Such columns may be connected with each other at peak (point) ‘p3’ via links ‘s’. The number of columns may vary depending upon the diameter of the inflatable member40. In an embodiment, the tubular member50includes six columns ‘CS’ as represented inFIG.2h. The above disclosed middle section50cof the tubular member50may reside over the inflatable member40and expands along with the inflatable member40to break the calcified tissues at the time of pre-dilation. Owing to the presence of larger cells and the aforesaid struts in the middle section50c, the stresses which act upon the tubular member50at the time of inflation-deflation distributes uniformly thereby reducing any chances of breakage of the struts therein.

The design of tubular member50help in distributing the forces that are created when the inflatable member40of balloon catheter100is inflated.

The above disclosed tubular member50may be attached with the catheter tubing10as shown inFIG.1with the help of at least two couplers60a,60b. The couplers60a,60bmay be secured at the distal end502and proximal end501of tubular member50. The couplers60a,60bmay be in the form of polymeric tubes or sleeves. In an embodiment, the couplers60a,60binclude two bonding sleeves. The couplers60a,60bmay be secured to the catheter tubing10and/or the tubular member50via any conventional technique such as without limitation, heating, gluing and welding. In an embodiment, the couplers60a,60bare attached via laser welding followed by the adhesive gluing and UV curing. Alternately, the couplers60a,60bare bonded with laser welding process to secure the tubular member50with the catheter tubing10and soft tip30. The parameters maintained during laser welding are provided as follows:

The aforesaid bonding provides high tensile strength and bonding strength to the tubular member50.

In an embodiment, the couplers60a,60binclude polymeric heat shrink tubes. The tube may be made of without limitation, nylon, polytetrafluoroethylene, polyether block amide, polyolefin, polyurethane, fluorinated ethylene propylene etc. In present invention, polyolefin tube is used for the attaching the tubular member50.

The outer diameter of the tube may range from 4.0 mm to 9.0 mm. In an embodiment, the outer diameter is 6.23 mm. The inner diameter of tube may range from 3.0 mm to 8.0 mm. In an embodiment, the inner diameter is 5.23 mm.

The foregoing present invention may be explained with the help of below examples:

A fatigue test was performed in order to test performance of the tubular member50. The fatigue test was performed by subjecting the balloon catheter100to rated burst pressure (RBP) by inflation for a predefined period of time. Further, the balloon is deflated and the process is repeated for 20 cycles. The experimental parameters maintained during the test are as follows.

It was observed that the tubular member50having straight link56detached after 3-5 cycles at a burst pressure of 5 atm. However, there was no detachment observed for the couplers60aand60bfrom the tubular member50even after 20 cycles of inflation and deflation even at burst pressure of 5 atm owing to uniform distribution of stress at both the proximal end501and distal end502of the tubular member50. Therefore, it provides more robustness to the tubular member50during deployment at the implantation site.

A trackability test of the balloon catheter100was performed in a three-dimensional model of the artery network consisting of a testing fluid (purified water). The model was fed with a guide wire. Once a predefined temperature is attained, the balloon catheter100was inserted into the model over the guide wire at a predefined insertion speed. Further, the force required to navigate the device across the model was calculated.

The experimental parameters maintained during the test are as follows.

FIG.3aandFIG.3bdepict a graphical representation of the force required in case of straight link and s-shaped links respectively. It was observed that force require for navigation of the balloon catheter100having s-shaped links56is two times less as compared to the balloon catheter100having the straight link56.

The scope of the invention is only limited by the appended patent claims. More generally, those skilled in the art will readily appreciate that all parameters, dimensions, materials, and configurations described herein are meant to be exemplary and that the actual parameters, dimensions, materials, and/or configurations will depend upon the specific application or applications for which the teachings of the present invention is/are used.