Description:FORM 2
THE PATENTS ACT, 1970
(39 of 1970)
&
THE PATENTS RULES, 2003
COMPLETE SPECIFICATION
(Section 10 and Rule 13)

TITLE OF THE INVENTION
COMPOSITE STENT

APPLICANT:
Meril Corporation (I) Private Limited, an Indian company of the address Survey No. 135/139, Muktanand Marg, Bilakhia House, Pardi, Vapi, Valsad-396191 Gujarat, India.

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

FIELD OF INVENTION
[1] The present disclosure relates to a medical device, more specifically, to a stent for the atrium.
BACKGROUND OF INVENTION
[2] Pulmonary arteries carry deoxygenated blood from the lungs to the heart. Pulmonary arterial hypertension (PAH) or Pulmonary hypertension is a condition defined by high blood pressure in the pulmonary arteries. Patients suffering from pulmonary hypertension have symptoms such as shortness of breath, fainting, tiredness, chest pain, swelling of the legs, and/or a fast heartbeat. The condition of pulmonary hypertension may be caused by the elevated pressure differential between the right atrium and the left atrium. The pressure differential is directly associated with the volume of blood entering the right atrium.
[3] Commonly, patients may be prescribed medications to manage the pressure differential by relaxing and dilating the blood vessels. Alternately, balloon septostomy may be performed. Balloon septostomy is a minimally invasive heart procedure in which a cardiologist uses a balloon catheter after puncturing the atrial septum wall to control the pressure of the left atrium. However, the said treatment options may not result in a definitive cure for elevated atrial pressure differential.
[4] A promising new approach for managing the pressure difference between the two atriums involves the use of stents placed across the septum separating the right atrium from the left atrium of the heart. This procedure, known as right atrial septostomy, creates a controlled channel of blood flow from the right atrium to the left atrium, bypassing the congested pulmonary circulation and reducing high blood pressure.
[5] However, the conventionally available stents for right atrial septostomy have high chances of migration after being implanted due to high blood pressure. Further, due to high blood pressure the diameter of the stent along its length may become non-uniform causing risks of turbulence and stagnate blood flow that can promote thrombus formation. The resultant thrombus may cause a heart attack and/or a brain stroke.
[6] Therefore, there is a need for a stent which overcomes these, and other disadvantages of stents known in the art.
SUMMARY OF INVENTION
[7] 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 mere 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.
[8] The present disclosure provides a composite stent including a braided portion and a machined portion. The braided portion includes a braided disc and a braided tubular segment, the braided tubular segment defines a fenestration hole. The machined portion includes a plurality of cells arranged in a plane, radially around a central axis of the stent. The arrangement of the cells forms a flower like structure. The machined portion includes a plurality of axial struts extending orthogonally from the plane of the plurality of cells. The plurality of axial struts is coupled to an inner circumference of the braided tubular segment.
BRIEF 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 apportioned 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 instrumentality disclosed herein. Moreover, those in the art will understand that the drawings are not to scale.
[10] Fig. 1 depicts a perspective view of a stent 100, in accordance with an embodiment of the present disclosure.
[11] Fig. 2 depicts a perspective view of a braided portion 110 of the stent 100, in accordance with an embodiment of the present disclosure.
[12] Fig. 3 depicts a perspective view of the stent 100, in accordance with an embodiment of the present disclosure.
[13] Fig. 4 depicts a perspective view of a machined portion 130 of the stent 100, in accordance with an embodiment of the present disclosure.
[14] Fig. 5 depicts a side view of the machined portion 130 of the stent 100, in accordance with an embodiment of the present disclosure.
DETAILED DESCRIPTION OF ACCOMPANYING DRAWINGS
[15] 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.
[16] Reference throughout this specification to “one embodiment,” “an embodiment,” or similar language means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment. Thus, appearances of the phrases “in one embodiment,” “in an embodiment,” and similar language throughout this specification may, but do not necessarily, all refer to the same embodiment, but mean “one or more but not all embodiments” unless expressly specified otherwise. The terms “including,” “comprising,” “having,” and variations thereof mean “including but not limited to” unless expressly specified otherwise. An enumerated listing of items does not imply that any or all of the items are mutually exclusive and/or mutually inclusive, unless expressly specified otherwise. The terms “a,” “an,” and “the” also refer to “one or more” unless expressly specified otherwise.
[17] Although the operations of exemplary embodiments of the disclosed method may be described in a particular sequential order for convenient presentation, it should be understood that the disclosed embodiments can encompass an order of operations other than the particular sequential order disclosed. For example, operations described sequentially may in some cases be rearranged or performed concurrently. 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, method, and apparatus can be used in combination with other systems, methods, and apparatuses.
[18] Furthermore, the described includes, 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 includes or advantages of a particular embodiment. In other instances, additional includes and advantages may be recognized in certain embodiments that may not be present in all embodiments. These includes 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.
[19] In accordance with the present disclosure, a composite stent (or stent) is disclosed. The stent is useful for the treatment of diseases associated with elevated atrial pressure such as pulmonary hypertension, heart failure, and the like. The stent of the present disclosure helps to control atrial pressure by diverting blood flow from the right atrium to the left atrium to address overloading one atrium, and maintain a suitable blood pressure. The stent helps to divert and increase the blood flow from the right atrium to the left atrium by creating a controlled communication channel between the two atriums thereby, reducing blood pressure in the right atrium as well as any associated risks of heart disease. The stent is implanted in the atrial septum wall, specifically, between the right and left atrium after performing balloon septostomy, a procedure in which a balloon catheter is used to create a hole on the septal wall between the left atrium and the right atrium.
[20] The stent of the present disclosure is a composite stent. The stent includes a braided portion, and a machined portion. The braided portion further includes a braided disc (which forms one atrial disc), and a braided tubular segment (which defines the fenestration hole). The machined portion includes a plurality of cells, arranged in a plane, radially around a central axis of the stent. The machined portion forms the other atrial disc. The braided portion and machined portion are coupled together (for example, welded) using orthogonal struts extending from the machined portion, along the inner circumference of the braided tubular segment. In various embodiments, the machined portion may be laser cut.
[21] The machined portion helps to fix the stent at the implantation site by maintaining proper grip and hold with the atrial walls while diverting the blood flow, thereby reducing chances of migration of the stent from the implantation site. Further, this creates a smooth flow path within the shunt, minimizing the risk of turbulence and stagnant flow that can promote blood clot or thrombus formation. As the crucial blood flow dynamics at the implantation site increases the risk of blood clot formation or thrombosis, the braided structure provides improved flexibility, reducing the risk of thrombosis.
[22] The stent of the present disclosure offers ability to the medical practitioner to customize the size and configuration of the communication channel between the two atriums thereby, providing a distinct solution for individual patients.
[23] The stent of the present disclosure provides enhanced visibility under imaging modalities such as fluoroscopy, intravascular ultrasound and so forth which aids in accurate placement and assessment of the stent increasing the rate of procedural success.
[24] The stent of the present disclosure is deployed via a minimal invasive delivery system including a loader, a delivery cable, a delivery sheath and a dilator. Any conventional delivery system can be used along with the teachings of the present disclosure.
[25] Now referring to figures, Fig. 1 depicts an embodiment of a composite stent 100 of the present disclosure, hereon referred as the stent 100. The stent 100 includes a composite structure defined between a proximal end 100a and a distal end 100b. The composite structure of the stent 100 is defined by a plurality of sections that are linked together to form the stent 100. The sections of the stent 100 include without limitation, a machined portion 130 towards the proximal end 100a and a braided portion 110 towards the distal end 100b. The braided portion 110 and the machined portion 130 may be coupled together to form the stent 100. The two portions may be coupled using any technique including, but not limited to welding, adhesive boding, mechanical fastening, interlocking and so forth. Each section may exhibit distinct properties such as, without limitation, flexibility, softness, and radial strength as explained below.
[26] In accordance with Fig. 2 of the present disclosure, the braided portion 110 is made of a plurality of filaments. The filaments may be made up of a biocompatible material including, but not limited to nitinol, stainless steel, cobalt chromium alloy, platinum, titanium, platinum-iridium, platinum-tungsten, and combination there off. The filament may have a pre-defined diameter in the range of 15mm to 45mm. The filaments of the braided portion 110 are braided together in a pre-defined braiding configuration. In an exemplary embodiment, the braiding configuration used is 1 over 1 or 1:1 braiding configuration. In another embodiment, double back braiding configuration is used in which a first circular layer is braided in 1:1 configuration followed by a second layer, braided in reverse direction over the first layer thereby providing two layers of braiding to the braided portion 110. Double back braiding configuration provides superior structural integrity and increased durability, ensuring better performance and reliability to the braided portion 110. Alternate braiding configurations can be used along with the teachings of the present disclosure.
[27] The filaments of the present disclosure are braided in a way, to form a plurality of segments. The braded portion 110 includes a tubular segment 111 and a disc segment (or disc) 113. The tubular segment 111, and the disc 113 may have different external diameters. In an exemplary embodiment, the tubular segment 111 has a diameter smaller than that of the disc 113. The length of the tubular segment 111 may be different from the length of the disc 113. In an exemplary embodiment, the length of the tubular segment 111 is greater than that of the disc 113. The disc 113 and the tubular segment 111 may be braided to form a single structure. In another embodiment, the disc 113 and the tubular segment 111 may be two distinct structures. The two different structures may be formed by braiding different sets of filaments in different braiding patterns and coupled thereafter by way of stitching, welding and the like.
[28] The tubular segment 111 is disposed between the disc 113 and the machined portion 130. The tubular segment 111 defines a fenestration hole. The fenestration hole allows the blood to pass through the atrial septal wall thereby creating the channel between the two atriums. The tubular segment 111 may be coupled to the machined portion 130 at the distal end 100b. The tubular segment 111 may have a predefined diameter corresponding to a channel to be created between the two atriums to optimize blood flow, ranging between 3mm and 14mm. The tubular segment 111 may have a pre-defined length extending between the disc 113 and the machined portion 130. In an embodiment, the axial length of the tubular segment 111 is between 3mm and 15mm. The tubular segment 111 may have a higher radial strength to keep the shunt from closing and/or collapsing.
[29] The disc 113 may be disposed towards the distal end 100b of the stent 100. The disc 113 may have a pre-defined external diameter. In an embodiment, the external diameter of the disc 113 ranges from 15mm to 35mm. The internal diameter of the disc 113 may be equal to the diameter of the tubular segment 111. The external diameter of the disc 113 may increase with the increase in the diameter of the tubular segment 111. The disc 113 may have higher flexibility. Such flexibility of the disc 113 helps the stent 100 to be held firmly at the implantation site and preventing any migration.
[30] The braided portion 110 may include open ends 115 defined by the plurality of filaments. The open ends 115 extend towards the distal end 100b. The open ends 115 may provide additional strength to the braided portion 110. To avoid causing any damage to the cardiac walls at the implantation site, the open ends 115 may be capped using a first jacket 117.
[31] In accordance with Fig. 3, the first jacket 117 may be disposed at the distal end 100b. The first jacket 117 may have a shape including, but not limited to a cylindrical shape, tapered shape, conical shape, tubular shape, and the like. The first jacket 117 may be provided with a tapered end. The first jacket 117 may be made up of a biocompatible material, including, but not limited to polyurethane, medical-grade polyester, titanium, and combination thereof. The first jacket 117 may have a pre-defined diameter corresponding to the number of filaments in the open ends 115, ranging from 2mm to 15mm. In an embodiment, the first jacket 117 has a friction fit with the open ends 115. Any other coupling method can be used including, but not limited to welding, snap fit, spot welding, crimping, laser welding, arc welding, and the same.
[32] Fig. 4 depicts the machined portion 130 of the stent 100 of the present disclosure. The machined portion 130 is disposed towards the proximal end 100a. The machined portion 130 may be made up of a biocompatible material such as, but not limited to, nitinol, platinum, stainless steel, cobalt-chromium, and the like. Use of a fluoroscopic biocompatible material, helps in easy tracking and deployment of the stent 100. The machined portion 130 is made using the laser cutting process. A sheet of the biocompatible material can be laser-cut to form the machined portion 130. The laser cutting process may provide optimal mechanical properties including, without limitation, flexibility, strength, and/or precision. Alternatively, the machined portion 130 may be manufactured using any of the process including, without limitation plasma cutting, CNC milling, electrical discharge machining (EDM), and so forth. The machined portion 130 includes a plurality of closed cells (or cells) 131, and a plurality of axial struts 133.
[33] As represented in Fig. 4, the machined portion 130 may include a plurality of closed cells (or cells) 131 disposed at the proximal end 100a. The plurality of cells 131 is arranged in a plane, radially around a central axis of the stent 100.The total number of cells 131 may range from 3 to 5 radially. The number of the cells 131 may also increase with increase in the diameter of the tubular segment 111.
[34] Each of the cells 131 includes an inverted ‘V’ shaped strut 131a and at least two or more linear struts 131b. At least one of the inverted ‘V’ shaped struts 131a may be coupled to the two linear struts 131b to form one of the cells 131. One of the linear struts 131b may be coupled to one of the two distal ends of the inverted ‘V’ shaped strut 131a. The linear struts 131b and the inverted ‘V’ shaped strut 131a may be coupled using a coupling method, including but not limited to welding, spot welding, crimping, laser welding, arc welding etc. In an embodiment, the laser welding is used. A plurality of cells 131 may be joined circumferentially to form a radial frame. The arrangement of the cells 131 forms a flower-like structure of the machined portion 130.
[35] The machined portion 130 may include curved ends 137 extending towards the proximal end 100a. The curved ends 137 of the linear struts 131b may be covered by a loading hub 135 (shown in Fig. 3) fixedly coupled with the curved ends 137 towards the proximal end 100a by means of a coupling mechanism including but not limited to friction fit, snap fit, bayonet fit and so forth. In an embodiment, the loading hub 135 includes a tube that covers the curved ends 137 of the linear struts 131b followed by a jacket towards the proximal end 100a.
[36] The loading hub 135 may have a pre-defined diameter. The diameter of the loading hub 135 may correspond to the diameter of the radial frame of the machined portion 130. The loading hub 135 may have a hollow cylindrical shape tapered at the proximal end. The loading hub 135 may be made up of a material including but not limited to stainless steel, cobalt-chromium, platinum, titanium, platinum-iridium, platinum-tungsten, and so forth. The loading hub 135 may have a pre-defined length. In an embodiment, the length of the loading hub 135 ranges from 1.20mm to 7mm. The loading hub 135 may assist during the implantation procedure (described later). The loading hub 135 may also serve as a cap at the proximal end of the stent 100 preventing loose ends of the cells 131 from coming in contact with a body vessel.
[37] In an exemplary embodiment, the loading hub 135 is provided with internal threads (not shown). The threads of the loading hub 135 are configured to mate with corresponding one or more threads on the outer surface of the delivery shaft of the transcatheter delivery system. The screw-type mechanism ensures easy attachment/detachment of the stent 100 from the delivery shaft and prevents slipping of the stent 100 with respect to the delivery shaft during loading and deployment of the stent 100.
[38] In accordance with Fig. 5, the machined portion 130 may include a plurality of axial struts 133 extending towards the distal end 100b. The axial struts 133 may be coupled to the linear struts 131b using techniques such as, but not limited to welding, spot welding, crimping, laser welding, arc welding, etc. The axial struts 133 extend orthogonally from the plane of the cells 131 thereby, making a right angle with the linear strut 131b of the cells 131. Alternately, the axial sturts 133 may be coupled to the linear struts 131b at a different angle including, but not limited to parallel, oblique angles and so forth. Each of the axial struts 133 may be coupled to one of the respective linear struts 131b. Each of the axial strut 133 is coupled to the respective linear strut 131b in a way that the position of each axial strut 133 may correspond to the diameter of the tubular segment 111. In another embodiment, the axial struts 133 may have a different coupling configuration with the linear struts 131b. The axial struts 133 impart radial strength to the stent 100.
[39] In an embodiment, the axial struts 133 may be utilized as a coupling means for the braided portion 110 and the machined portion 130. The machined portion 130 is coupled with the braided portion 110 by coupling the axial struts 133 with the tubular segment 111 of the braided portion 110. In an embodiment, the axial struts 133 are fixedly coupled to an inner circumference of the tubular segment 111. The axial struts 133 may be coupled to the tubular segment 111 using techniques such as, but not limited to welding, soldering, adhesive bonding, mechanical fastening, and so forth. In an embodiment, the axial struts 133 are coupled with the tubular segment 111 using adhesive bonding, mechanical interlocking, and so forth. The length of the axial struts 133 may correspond to the length of the tubular segment 111 of the braided portion 110. The number of the axial struts 133 may correspond to the number of the cells 131. In an embodiment, the number of the axial struts 133 is equal to the number of cells 131.
[40] The stent 100 of the present disclosure may be implanted at the target site using a minimal invasive technique, such as trans-catheterization. The trans-catheterization or transcatheter delivery of the stent 100 is carried out by using a delivery catheter or sheath (not shown).
[41] The stent 100 is pre-loaded onto a delivery shaft. For this, the delivery shaft is passed through a loader, after which the device is loaded onto the delivery shaft by rotating it, say, clockwise five times. Once secured, the delivery shaft is retracted from the loader, ensuring the device is properly loaded.
[42] For delivery of the stent 100, post mounting of the stent 100 onto the delivery shaft, the delivery shaft is minimally invaded into the patient’s body via an appropriate vascular access point, e.g., through the transfemoral groin of a patient. The catheter/ sheath is navigated to the target site (i.e., Atrial septal wall) with the help of a guide wire (not shown). Fluoroscopic imaging techniques may be used to guide and monitor the advancement of the catheter/sheath during the procedure.
[43] Once the catheter/sheath approaches the target site, the braided portion 110 of the stent 100 is first pushed through the septal wall between the left atrium and right atrium followed by the machined portion 130. Once the stent 100 is fixed properly on the septal wall, the stent 100 is detached from the delivery shaft. The catheter and delivery shaft are thereafter removed from the body.
[44] 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. , Claims:CLAIMS:
1. A stent (100) comprising:
a braided portion (110) including a disc (113) and a tubular segment (111), the tubular segment (111) defines a fenestration hole; and
a machined portion (130) comprising a plurality of cells (131) arranged in a plane, radially around a central axis of the stent (100), the machined portion (130) includes a plurality of axial struts (133) extending orthogonally from the plane of the plurality of cells (131);
2. The stent (100) as claimed in claim 1, wherein the braided portion (110) is made of a plurality of filaments braided together in a pre-defined braiding configuration including 1 over 1 braiding configuration or a double back braiding configuration.
3. The stent (100) as claimed in claim 1, wherein the braided portion (110) includes open ends (115) capped using a first jacket 117.
4. The stent (100) as claimed in claim 1, wherein the machined portion (130) is made using one of a laser cutting process, plasma cutting, CNC milling, or electrical discharge machining (EDM).
5. The stent (100) as claimed in claim 1, wherein the plurality of axial struts (133) is coupled to the inner circumference of the tubular segment (111).
6. The stent (100) as claimed in claim 5, wherein the plurality of axial struts (133) is coupled to the inner circumference of the tubular segment (111) through welding.
7. The stent (100) as claimed in claim 1, wherein the arrangement of the cells (131) forms a flower like structure.
8. The stent (100) as claimed in claim 1, wherein each of the cells (131) of the) includes an inverted ‘V’ shaped strut (131a) and two or more linear struts (131b).
9. The stent (100) as claimed in claim 8, wherein the machined portion (130) include curved ends (137).
10. The stent (100) as claimed in claim 9, wherein the curved ends (137) are covered by a loading hub (135).
11. The stent (100) as claimed in claim 1, wherein the plurality of axial struts (133), are coupled to the linear struts (131b).