Claims:WE CLAIM
1. A shunt comprising:
i. a proximal end including a disc to support a right atrium side of a septal wall;
ii. a distal end including a flat disc to support a left atrium side of the septal wall;
iii. an intermediate portion disposed between the proximal end and the distal end, the intermediate portion including a neck portion to provide a passage between the left atrium and the right atrium of the septal wall;
wherein the dimensions of the proximal end, distal end and the intermediate portion are selected to provide a low crimp profile ranging from 2mm to 3mm.
2. The shunt as claimed in claim 1 wherein the disc at the proximal end includes a flared disc.
3. The shunt as claimed in claim 2 wherein the flared disc is aligned with respect to the flat disc of the shunt at an angle of inclination ranging from 40° to 80°.
4. The shunt as claimed in claim 2 wherein the flared disc includes an outer diameter in a range of 15mm to 24mm.
5. The shunt as claimed in claim 2 wherein the intermediate region includes an inner diameter in a range of 5mm to 10mm.
6. The shunt as claimed in claim 2 wherein the intermediate region includes a height in a range of 2mm to 5mm.
7. The shunt as claimed in claim 1 wherein the disc at the proximal end includes a curvature disc.
8. The shunt as claimed in claim 7 wherein the curvature disc includes an outer diameter in a range of 15mm to 24mm.
9. The shunt as claimed in claim 7 wherein the curvature disc is aligned with respect to the intermediate region of the shunt at an angle of inclination ranging from 40° to 80°.
10. The shunt as claimed in claim 7 wherein the intermediate region includes an inner diameter ranging from 5mm to 10mm.
11. The shunt as claimed in claim 7 wherein the intermediate region includes a height in a range of 6mm to 12mm.
12. The shunt as claimed in claim 1 wherein the distal end and the intermediate portion includes a plurality of cavities to accommodate one or more radiopaque markers.
13. A shunt, comprising:
i. a proximal end including a curvature disc to support a right atrium side of a septal wall;
ii. a distal end including a plurality of barbs to support a left atrium side of a septal wall;
iii. an intermediate portion disposed between the proximal end and the distal end, the intermediate portion including a neck portion to provide a passage between the left atrium and the right atrium of the septal wall;
wherein the dimensions of the proximal end, distal end and the intermediate portion are selected to provide a low crimp profile ranging from 2mm to 3mm.
14. The shunt as claimed in claim 13 wherein the plurality of barbs includes 6 to 12 barbs.
15. The shunt as claimed in claim 13 wherein the barbs has a length ranging from 3mm to 8mm and width ranging from 1mm to 3mm.
16. The shunt as claimed in claim 13 wherein the curvature disc is aligned with respect to the intermediate at an angle of inclination ranging from 40° to 80°.
17. The shunt as claimed in claim 13 wherein the intermediate region includes a height in a range of 6mm to 12mm.
18. The shunt as claimed in claim 13 wherein the intermediate region includes an inner diameter in a range of 6mm to 9mm
19. The shunt as claimed in claim 13 wherein the curvature disc includes an outer diameter in a range of 15mm to 24mm. ,

Description:THE PATENTS ACT, 1970
(39 of 1970)
&
THE PATENTS RULES, 2003
COMPLETE SPECIFICATION
(Section 10 and Rule 13)

1. TITLE OF THE INVENTION:
INTERATRIAL SHUNT

2. APPLICANT:
Meril Life Sciences Pvt. Ltd., an Indian company of the address Survey No. 135/139 Bilakhia House, Muktanand Marg, Chala, Vapi- 396191, Gujarat

The following specification particularly describes the invention and the manner in which it is to be performed:

FIELD OF INVENTION
[1] The present invention relates to an interatrial shunt (IAS). More specifically, the present invention relates to the design of the interatrial shunt (IAS).
BACKGROUND
[2] The most common heart problem occurs due to an increase in blood pressure in the left atrium or when the left atrium is unable to accept an adequate volume of blood at normal diastolic pressure leading to diastolic dysfunction. The aforesaid heart complication may be treated using different approaches such as pharmacological treatment as a first line of treatment and/or surgical treatment. Other treatments may include implantation of shunt to reduce pressure in the left atrium.
[3] A self-expandable shunt may be placed on the septal wall to create an open passage between the right atrium and left atrium which results in elevated blood of left atrium to flow towards right atrium due to pressure differentiation. Subsequently, pressure is reduced in the left atrium and the chances of a heart stroke are minimized.
[4] The difference in blood pressure between the two chambers of the heart may be referred to as the blood pressure gradient. The blood pressure gradient is responsible for the flow of blood from the left atrium to the right atrium. However, the conventional shunt used to transfer blood from the left atrium to the right atrium may pose the problem of increase in pressure gradient leading to detrimental effects for patients.
[5] Further, the conventional shunt used for treatment may not have a size in accordance with the septal wall of heart which may lead to stress generation on the septal wall of the heart as well as cause damage to the adjacent walls of the heart. Also, there may be a chance of migration or deviation of the shunt after implantation due to instability of device under high blood pressure.
[6] Moreover, the conventional shunt used may have a different design, for example, as disclosed in prior art WO2018158747A1, the shunt does not include a flat disc structure at one of the end which may pose several disadvantages such as inadequate adherence to septal wall at one of the end and/or device patency may not be maintained to fulfil the requirement.
[7] Therefore, there exists a need for an improved intra atrial shunt that can overcome limitations of the existing ones.
SUMMARY
[8] The present invention discloses an interatrial shunt. The shunt includes a proximal end including a disc to support a right atrium side of a septal wall, a distal end including a flat disc to support a left atrium side of the septal wall and an intermediate portion disposed between the proximal end and the distal end, the intermediate portion including a neck portion to provide a passage between the left atrium and the right atrium of the septal wall. Further, the dimensions of the proximal end, distal end and the intermediate portion are selected to provide a low crimp profile ranging from 2mm to 3mm.
BREIF DESCRIPTION OF DRAWINGS
[9] The summary above, as well as the following detailed description of illustrative embodiments, is better understood when read in conjunction with the appended drawings. For the purpose of illustrating the present disclosure, exemplary constructions of the disclosure are shown in the drawings. However, the disclosure is not limited to specific methods and instrumentalities disclosed herein. Moreover, those in the art will understand that the drawings are not to scale.
[10] Fig.1 represents a schematic view of the shunt in accordance with an embodiment of the present invention.
[11] Fig.1A represents a front view of the shunt of Fig.1 implanted on septal wall in accordance with an embodiment of the present invention.
[12] Fig.2 represents a schematic view of another embodiment of the shunt in accordance with an embodiment of the present invention.
[13] Fig.2A represents a front view of the shunt of Fig.2 implanted on septal wall in accordance with an embodiment of the present invention.
[14] Fig.3 represents a schematic view of another embodiment of the shunt in accordance with an embodiment of the present invention.
[15] Fig.3A represents a front view of the shunt of Fig.3 implanted on septal wall in accordance with an embodiment of the present invention.
[16] Fig.4 represents a process involved in manufacturing of the shunt in accordance with an embodiment of the present invention.
[17] Fig.5A-5B represents front view of the laser cut tubes in accordance with an embodiment of the present invention.
[18] Fig.6A_6B represents a flow chart depicting a process involved in molding of the laser cut tubes in accordance with an embodiment of the present invention.
[19] Fig.7 represents a front view of a mold to form the shunt depicted in Fig. 1 in accordance with an embodiment of the present invention.
[20] Fig. 7A represents a front view of molding of the laser cut tube in accordance with an embodiment of the present invention.
[21] FIG.8 represents a front view of a mold to form the shunt depicted in fig. 2 in accordance with an embodiment of the present invention.
[22] Fig.8A-8B represents a front view of molding of the laser cut tube in accordance with an embodiment of the present invention.
DETAILED DESCRIPTION OF DRAWINGS
[23] 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.
[24] Particular embodiments of the present disclosure are described herein below with reference to the accompanying drawings, however, it is to be understood that the disclosed embodiments are merely examples of the disclosure, which may be embodied in various forms. Well-known functions or constructions are not described in detail to avoid obscuring the present disclosure in unnecessary detail. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a basis for the claims and as a representative basis for teaching one skilled in the art to variously employ the present disclosure in virtually any appropriately detailed structure.
[25] In accordance with the present disclosure, a shunt and its method of manufacturing are disclosed. In various embodiments, the shunt may be implanted between two ventricles of the heart, or between any other two body cavities. In an embodiment, the shunt is implanted on a septal wall between a left atrium and a right atrium of the heart in a patient. The shunt may create a passage or vent between the left atrium and the right atrium to divert elevated blood flow from the left atrium to the right atrium in controlled manner to reduce the chances of diastolic heart failure.
[26] The shape and dimension of the shunt may play a vital role in the treatment of diastolic heart diseases. In an embodiment, the shunt includes a flared disc on one end, a flat disc on another end and a neck portion between the flared disc and the flat disc. In another embodiment, the shunt includes a curvature disc on one end, a flat disc on another end and a high length neck portion between the curvature disc and the flat disc. The aforesaid shapes of the shunt have enhanced strength, provide adequate conformity to the septal wall of the heart and/or can be deployed at the treatment site with ease. Further, the aforesaid shapes of the shunt provide enhanced performance under low and high blood pressure at the left atrium by creating a passage for blood flow from the left atrium to the right atrium. The blood flow from the left atrium to the right atrium significantly reduces the excess blood pressure at the left atrium, thereby preventing detrimental consequences to the patient.
[27] In another embodiment, a nitinol tube is subjected to a process of the molding in order to obtain a desired shape of the shunt as per patient’s heart anatomy. The adequate shape of the shunt helps in reducing stress at an implantation site, conforms adequately to the septal wall and/or reduces chances of migration or deviation of the shunt at the implantation site.
[28] Now referring specifically to drawings, in an embodiment as depicted in FIG.1, a schematic view of a shunt 100 is disclosed. The shunt 100 may include a frame 10. The shunt 100 is self-expandable and/or has a low crimp profile. The crimp profile of the shunt 100 may be in a range of 2mm to 3mm. The low crimp profile of the shunt 100 may help to load the device effortlessly and smoothly into a catheter. The shunt 100 may be delivered via the catheter of low profile, for example, 10F to 14F.
[29] The frame 10 of the shunt 100 may be made of a biocompatible material. The biocompatible material may include without limitation, stainless steel alloy, nitinol alloy, cobalt-chromium (Co-Cr) alloy. In an embodiment, the frame 10 is made of nitinol alloy. The nitinol alloy is chosen due to its enhanced elasticity and/or shape memory properties.
[30] The frame 10 of the shunt 100 includes a proximal end 12, a distal end 14 and an intermediate region 16 between the proximal end 12 and the distal end 14. In an embodiment, the frame 10 includes a flair disc at the proximal end 12, and a flat disc at the distal end 14 (as depicted in FIG.1). In another embodiment, the intermediate region 16 of the frame 10 includes a neck portion (as depicted in FIG.1).
[31] The frame 10 may include a plurality of cells formed by a plurality of struts 15. The width of the struts 15 may be in a range of 180µm to 300µm. In an embodiment, the width of the struts 15 is in a range of 200µm to 280 µm. In an embodiment, the frame 10 includes two rows of cells 11 and 13. The cells 11 may constitute the flair disc of the frame 10 and the cells 13 may constitute the flat disc of the frame 10 (as depicted in FIG.1). The two rows of cells (11, 13) may be fabricated in any shape such as lotus, cone, hour glass. The two rows of cells (11, 13) may be fabricated in similar or different shapes. In an embodiment, cells (11, 13) of the two rows are in the shape of a petal. The cells (11, 13) of the two rows may be of predefined dimensions in line with native anatomy where the frame 10 is to be implanted. The width and length of the cells (11, 13) may be similar or different. The width and length of the cells (11, 13) may be in a range of 2mm to 5mm and 7mm to 15mm. In an embodiment, the width and length of the cells (11, 13) is 3mm to 4mm and 8mm to 12mm respectively.
[32] In accordance with an embodiment, FIG.1A shows the front view of implanted shunt 100 on septal wall of heart. The proximal end 12 and the distal end 14 are configured to partially engage and protrude beyond the right and left sides of the atrial septum upon implantation. The flair disc at the proximal end 12 and the flat disc at the distal end 14 of the frame 10 may help to accommodate the shunt 100 at the septal wall and/or prevent migration/deviation of the shunt 100 from its location. The neck portion at the intermediate region 16 of frame 10 may help in reduction of blood pressure in the left atrium by effectively diverting the blood to the right atrium. FIG.1A shows the Further, the aforesaid shape of the shunt 100 may be easily loaded in the catheter and/or may provide immediate reduction of blood pressure at the left atrium due to the flair disc and neck portion of the frame 10 of the shunt 100.
[33] The flair disc at the proximal end 12 and the flat disc at the distal end 14 include an outer diameter. The outer diameter of the proximal end 12 and the distal end 14 may be similar or different. In an embodiment, the outer diameter of the proximal end 12 and distal end 14 is same. The outer diameter of the proximal end 12 and the distal end 14 may be in range of 15mm to 24mm. In an embodiment, the outer diameter of the proximal end 12 and the distal end 14 is 19mm and 19mm respectively.
[34] The neck portion at the intermediate region 16 may include an inner diameter and a predefined height depending upon the patient’s heart anatomy. The aforesaid parameters of the neck portion play a vital role in the treatment of the diastolic dysfunction. The adequate diameter of the neck portion is required to provide adequate blood flow from the left atrium to the right atrium, thereby achieving required blood pressure at the left atrium.
[35] The inner diameter of the intermediate region 16 may be in range of a 5mm to 10mm. In an embodiment, the inner diameter is 8mm. The predefined height of the intermediate region overall 16 may be in a range of 2mm to 5mm. In an embodiment, the predefined length of the intermediate region 16 is 3mm.
[36] In an embodiment, the distal end 14 and the intermediate region 16 of the shunt 100 includes a plurality of cavities 18. The plurality of cavities 18 may be provided to accommodate radiopaque markers to enhance visualization of the shunt 100 under fluoroscopy. The radiopaque markers may include but not limited to gold, platinum, platinum-iridium, silver, tantalum, niobium, zirconium, hafnium, etc. In an embodiment, the radiopaque markers include tantalum markers.
[37] In an embodiment, the cells 11 constituting the flair disc at the proximal end 12 and the cells 13 constituting the flat disc 14 at the distal end 14 may be aligned at a predefined angle of inclination, for example, A1. The angle of inclination (A1) between the flair disc and the flat disc may be in a range of 40° to 80°, more preferably in between 50° to 70°. In an embodiment, the angle of inclination (A1) is 60°. The angle of inclination (A1) may depend upon the thickness of the septal wall. The inclination between the flair disc and the flat disc may help to load the shunt 100 smoothly as well as may minimize jerking during deployment procedure. Moreover, the inclination may help to properly accommodate the shunt 100 with the atrial septal wall of a patient.
[38] Further, the shunt 100 may be made in a wide range of sizes that comply with the dimension of the atrial septal wall of the heart. An appropriate size of the shunt 100 as per the dimension of the atrial septal wall may help in controlled transfer of blood from the left atrium to the right atrium to achieve desired pressure in both upper chambers of the heart.
[39] The shunt 100 may be formed using predefined dimensions. The predefined dimensions of the shunt 100 may include without limitation, the outer diameter of the proximal end 12 and the distal end 14, the height and the inner diameter of the intermediate region 16 between the proximal end 12 and the distal end 14. In an embodiment, the predefined dimensions of the shunt 100 are selected from progressively increasing ranges.
[40] The progressively increasing range of the inner diameter of the intermediate region 16 and the outer diameter of the proximal end 12 and the distal end 14 of the shunt 100 may depend upon septal wall height. The septal wall height may range from 23mm to 40mm.The progressively increasing range of the inner diameter of the intermediate region of the shunt 100 may be in range of 0.5mm to 1.5mm. The progressively increasing range of the outer diameter of the proximal end 12 and the distal end 14 of the shunt 100 may be in range of 0.5mm to 2mm.
[41] The progressively increasing range of the height of the shunt 100 may depend upon septal wall thickness and maybe in a range of 0.5mm to 2.0mm. The thickness of the septal wall ranges from 2mm to 6mm.
[42] Table 1 given below shows an exemplary size range of the shunt 100 as per the dimension of the atrial septal wall of the heart.
Size 1 Size 2 Size 3 Size 4
Atrial Septal wall height (mm) 23-26 27-30 31-35 36-40
Shunt Height (mm) 6 8 10 12
Shunt (Intermediate region) inner diameter (mm) 6 7 8 9
Shunt (proximal and distal disc) outer diameter (mm) 15 17 19 21

[43] In another embodiment, as depicted in FIG.2, a schematic view of the shunt 200 is disclosed. The shunt 200 includes a frame 20. The frame 20 includes a proximal end 22, a distal end 24 and an intermediate region 26 between the proximal end 22 and the distal end 24. In an embodiment, the proximal end 22 of the frame 20 includes a curvature disc, the distal end 24 includes a flat disc and the intermediate region 26 includes a neck portion. The curvature disc at proximal end of the frame 20 may help to properly accommodate the shunt 200 at the septal wall and/or may prevent migration of the shunt 200 from the treatment site.
[44] The frame 20 may include a plurality of large cells 23, medium cells 25 and small cells 27 formed by a plurality of struts 21. The width of the struts 21 may be in a range of 140µm to 220µm, more preferably in between 160µm to 200µm.
[45] The large cells 23 may curve distally towards the distal end 24 of the frame 20 to form the curvature disc at the proximal end 22 of the frame 20 (as depicted in FIG. 2). The large cells 23 may be curved at a predefined angle of inclination with respect to the intermediate region, for example B1. The angle of inclination (B1) may be in a range of 40° to 80°, more preferably in between 50° to 70°. In an embodiment, the angle of inclination (B1) is 55°. The angle of inclination helps to load the implant smoothly and uniformly as well as it may minimize the jerking effect during deployment procedure due to less number of cells. Moreover, it will well accommodate with the atrial septal wall thickness as per patient’s heart anatomy.
[46] The large cells 23 may be fabricated in shapes such as pear, petal, diamond, combat, sigma, etc. In an embodiment, the large cells 23 are fabricated in the shape of a petal. The large cells 23 may be fabricated in predefined dimensions. The large cells 23 may have a length and width in the range of 7mm to 15mm and 2mm to 5mm. In an embodiment, the large cells 23 have a length of 11mm and a width of 3mm respectively.
[47] The medium cell 25 constitutes the neck portion of the frame 20. In an embodiment, the medium cells 25 are molded at one end to form the flat disc of the frame 20 (as depicted in FIG.2). The medium cells 25 may be fabricated in shapes such as diamond, petal, etc. In an embodiment, the medium cells 25 are fabricated in the shape of a petal. The medium cells 25 may be fabricated in predefined dimensions. The medium cells 25 may have length and width in the range of 5mm to 8mm and 1mm to 3mm respectively. In an embodiment, the medium cells 25 have a length of 7mm and width of 2mm.
[48] The small cells 27 constitute the flat disc of the frame 20. The small cells 27 may be fabricated in shapes such as diamond, petal, etc. In an embodiment, the small cells 27 are fabricated in the shape of a petal. The small cells 27 may be fabricated in predefined dimensions. The small cells 27 may have length and width in range of 3mm to 6mm and 1mm to 3mm respectively. In an embodiment, the small cells 27 have a length of 4mm and width of 1.5mm.
[49] In accordance with an embodiment of the present invention, FIG.2A shows a front view of implanted shunt 200 on septal wall of heart. The aforesaid shape of the shunt 200 may provide large number of struts 21 at the distal end 24 which provides more support at the septal wall leading to prevention of deviation of the shunt 200.
[50] The proximal end 22 and the distal end 24 of the shunt 200 includes an outer diameter. The outer diameter of the proximal end 22 and the distal end 24 may be same or different. In an embodiment, the outer diameter of the proximal end 22 and distal end 24 is same. The outer diameter of the proximal end 22 and the distal end 24 may be in a range of 15 mm to 24 mm. In an embodiment, the outer diameter of the proximal end 22 and the distal end 24 is 19mm and 19mm respectively.
[51] The neck portion at the intermediate region 26 of the frame 20 may include an inner diameter, and a predefined length. The inner diameter of the intermediate region 26 may be in range of a 5mm to 10mm. In an embodiment, the inner diameter is of the intermediate region 26 is 8mm.
[52] The height of the intermediate region 26 may be greater to maintain passage on the septal wall open for enough flow of blood from the left atrium to the right atrium and/or to provide sufficient angle of inclination to the curvature disc which results in enhanced holding capacity of the shunt 200 at the septal wall of a patient. The height of the intermediate region 26 may be in a range of 6mm to 12mm. In an embodiment, the height of the intermediate region 26 is about 5mm to 12mm.
[53] In yet another embodiment, the distal end 24 of the frame 20 includes a plurality of barbs 30 (as depicted in FIG.3). In an embodiment, the frame 20 includes 6-12 barbs 30. The length of the barbs 30 may be in a range of 3mm to 8mm and width may be in range of 1mm to 3mm. In accordance with an embodiment of the present invention, FIG.3A shows a front view of implanted shunt 200 on septal wall of heart. The barbs 30 of the shunt 200 may provide spring-back effect and/or possess enhanced strength due to which the shunt 200 can withstand rapid fluctuations of blood pressure. Further, the barbs 30 of the shunt 200 include blunt edges that prevent penetration of the septal wall during deployment and placement shunt 200.
[54] Optionally, the flat disc of the shunt (100, 200) may be covered with a fabric (not shown) leading to faster tissue growth, prevention of deviation of the shunt (100, 200) from the site of implantation and enhanced adherence to the septal wall of the heart. The fabric may be attached by means of without limitation, shrink process or stitching. The fabric may be selected from but not limited to polytetrafluoroethylene (PTFE), polyethylene terephthalate PET or any non-degradable material. In an embodiment, the fabric is made of PET or PTFE. The thickness of the fabric may be in a range of 80µ to 200µ. In an embodiment, the thickness of the fabric ranges from 100µ to 170µ.
[55] Additionally, the shunt (100,200) may include a bi-leaflet/tri-leaflet tissue (not shown) to provide a unidirectional flow of blood from the left atrium to the right atrium and restricts backflow of blood from the right atrium to the left atrium of heart. The tissue may be attached to the proximal end of the shunt (100, 200). The tissue may be attached by means of without limitation, suturing. The thickness of the tissue may be in a range of 50µ to 500µ, more preferably 80µ to 400µ.
[56] In accordance with an embodiment of the present invention, FIG.4 represents a flow chart depicting a process involved in the fabrication of the shunt 100. The process of fabrication of the shunt 100 commences by laser cutting the nitinol tube (not shown) at step 401. The nitinol tube maybe laser cut in different designs in order to obtain desired shapes of the shunt as disclosed above. In an embodiment, the nitinol tube is laser cut to obtain laser-cut tubes 32 and 34 as shown in FIG. 5A, and FIG.5B respectively. The laser-cut tube 32 has a proximal end 31 and a distal end 33. The laser-cut tube 34 has a proximal end 35 and a distal end 37.
[57] After laser cutting at step 401, the laser cut tubes (32, 34) are subjected to a process of grinding and honing at step 403. The process of grinding and honing may be performed in order to remove the burrs generated during the process of laser cutting. The process of grinding and honing may be performed by means of without limitation diamond and/or abrasive gel which cleans or remove the burrs generated during the laser cutting to provide a smooth surface.
[58] At step 405, the laser cut tubes (32, 34) of step 403 are subjected to a process of molding and shape setting. The process of molding of the laser cut tubes 32 and 34 may be performed to obtain a desired shape of the shunt (as disclosed in FIG.1 and FIG.2). The laser-cut tubes (32, 34) may be subjected to a number of predefined steps of molding. The number of predefined steps may be in a range of 2-3 steps.
[59] In an exemplary embodiment, the shunt 100 as depicted in FIG.1 is obtained by molding the laser cut tube 32 on a mold 50 (depicted in FIG.7). The mold 50 may include two upper portions 51a and 51b and a lower portion 52. Alternatively, the mold 50 may include one upper portion. The shunt 100 as depicted in FIG. 1 may be fabricated by molding the laser cut tube 32 on the mold 50 at a temperature ranging from 500°C to 520°C. The process of molding may be performed for a predefined time. In an embodiment, the molding is performed for 15 minutes.
[60] FIG. 6A represents a flow chart depicting a process involved in the molding of the laser cut tube 32 in accordance with an embodiment of the present invention. The molding of the laser cut tube 32 commences at step 601. At this step, the distal end 33 of the laser cut tube 32 is placed on the lower portion 52 of the mold 50 (as depicted in FIG.7A). At step 603, the distal end 33 of the laser cut tube 32 is flared against the lower portion 52 of the mold 50 to fabricate the flat disc structure at the distal end 33 of the laser cut tube 32. The flaring of the distal end 33 may be performed at a temperature in range of 450°C to 550°C, preferably in a range of 500°C to 520°C. In an embodiment, the flaring of the distal end 33 is performed at a temperature in range of 450°C to 550°C. At step 605, the flair disc structure is fabricated at the proximal end 31 by placing the upper portions 51a and 51b on the proximal end 31 of the laser cut tube 32 as shown in FIG.7A. The flaring of the distal end 31 may be performed at a temperature in range of 450°C to 550°C, preferably in a range of 500°C to 520°C. In an embodiment, the flaring of the distal end 31 is performed at a temperature in range of 450°C to 550°C.
[61] In another exemplary embodiment, the shunt 200 as depicted in FIG.2 is obtained by molding the laser cut tube 34 on the mold 60 (depicted in FIG.8). The mold 70 may include two upper portions 71a and 71b, two middle portions 71c and 71d and a lower portion 72. Alternatively, the mold 60 may include one upper portion and one middle portion. The shunt 200 as depicted in FIG.2 may be fabricated by molding the laser cut tube 34 on the mold 70.
[62] FIG. 6B represents a flow chart depicting a process involved in the molding of the laser cut tube 34 in accordance with an embodiment of the present invention. The molding of the laser cut tube 34 commences at step 701. At this step, the distal end 37 of the laser cut tube 34 is placed between the lower portion 72 and the middle portion 71c and 71d of the mold 70 as depicted in FIG. 8A. At step 703, both the proximal end 35 and the distal end 37 of the laser cut tube 34 are flared against the middle portion 71c and 71d and the lower portion 72 of the mold 70 respectively. The aforesaid step is performed at a temperature in a range of 450°C to 550°C, preferably ranges from 500°C to 520°C. In an embodiment, the temperature is 505°C. The above step leads to fabrication of the flat disc at the distal end of the laser cut tube 34. Lastly, at step 705, the proximal end 35 of the laser cut tube 34 is further molded against the upper portion 71a and 71b (as depicted in FIG.8b) to fabricate the curvature disc of the shunt 200.
[63] At step 407, the shunt obtained at the above steps is subjected to a process of sandblasting. The process of sandblasting may be performed by propelling a stream of abrasive material at a predefined pressure. The process of sandblasting may be performed in order to remove oxidized layer generated on an upper surface of the IAS during the process of shape setting.
[64] Lastly, the process of electropolishing is performed at step 409. The process of electropolishing may be performed in order to remove the impurities generated during various above processes. The process of electropolishing may be performed by dipping the shunt into a concentrated solution of 20% to 25% perfluoric acid and 75% to 80% acetic acid. The process of electropolishing may be conducted in presence of current in a range of 0.8A to 0.10A and voltage in a range of 8v to 12v.
[65] Now the invention will be explained with the help of following examples.
[66] Example 1: Native anatomy of the septal wall included the height of the septal wall of around 24mm and the thickness of the septal wall of around 3mm. In such case, a shunt having a flared disc at the proximal end with the outer diameter 15mm, a flat disc at the distal end with the outer diameter 15mm and the intermediate region between the flared disc and the flat disc having the height 3mm and inner diameter 6mm was used. The flair disc at the proximal end facilitated adequate placement of the shunt at right atrium side of the septal wall and/or prevent migration/deviation of the shunt from its location. The flat disc at the distal end facilitated adequate placement of the shunt at left atrium side of the septal wall and/or provided better adhesion to the shunt at the site of implantation. The appropriate height of the intermediate region helped to keep the passage open between the left atrium and the right atrium and/or provide significant reduction in blood pressure at the left atrium. Further, the angle of inclination between the flared disc and the flat disc was 60°. The said angle of inclination helped to load the device smoothly and uniformly into catheter of size 12F.
[67] Example 2: Native anatomy of the septal wall included the height of the septal wall of around 26mm and the thickness of the septal wall of around 4mm. In such case, a shunt having a flat disc at the distal end with the outer diameter 17mm, a curvature disc at the proximal end with the outer diameter 17mm and a high neck intermediate region between curvature disc and flat disc having the height 8mm and inner diameter of around 7mm was used. The flat disc at the distal end facilitated adequate placement of the shunt at left atrium side of the septal wall and/or minimized chances of migration of the shunt at the site of implantation. The curvature disc at the proximal end enabled adequate placement of the shunt at right atrium side of the septal wall, and/or provided enough holding capacity to the shunt to facilitate blood transfer from high pressure side (left atrium) to lower blood pressure side (right atrium). Further, the appropriate height of the intermediate region helped to keep the passage open between the left atrium and the right atrium and/or provided significant reduction in blood pressure at the left atrium. Further, the angle of inclination between the high neck intermediate region and the curvature disc was 55°. The said angle of inclination of the device helped in shape recovery as well as smooth loading of the device into the catheter of size 12F.
[68] Example 3: Native anatomy of the septal wall included the height of the septal wall of around 32mm and the thickness of the septal wall of around 4mm. In such case, a shunt having a plurality of barbs at distal end forming a flat disc with the outer diameter 19mm, a curvature disc at the proximal end with the outer diameter 19mm and the intermediate region between the curvature disc and the flat disc having the height of 10mm and inner diameter around 8mm was used. The curvature disc at the proximal end enabled adequate placement of the shunt at right atrium side of the septal wall, and/or provided enough holding capacity to the shunt to facilitate blood transfer from high pressure side (left atrium) to lower blood pressure side (right atrium). The flat disc at the distal end facilitated adequate placement of the shunt at left atrium side of the septal wall and/or the barbs helped to withstand rapid fluctuations of blood pressure at the left atrium. An appropriate height of the intermediate region helped to keep the passage open between the left atrium and the right atrium and/or provided significant reduction in blood pressure at the left atrium. Further, the angle of inclination between the high neck intermediate region and the curvature disc was 55°. The said angle of inclination of the device helped in shape recovery as well as smooth loading of the device into the catheter of size 12F.
[69] 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.