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

1. TITLE OF THE INVENTION:
STENT INTERLOCKING ASSEMBLY

2. 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
[001] The present invention relates to a medical implant. The invention particularly relates to an interlocking assembly between two stents.
BACKGROUND OF THE INVENTION
[002] The coronary artery is a blood vessel responsible for delivering oxygenated blood to the heart. A blockage or narrowing of the coronary artery is often due to the accumulation of fat, cholesterol, and other substances in and on an internal wall of artery coronary artery, a condition called atherosclerosis. Atherosclerosis is a common cause of blockage in the coronary artery. The blockage or narrowing of the blood vessel is called coronary artery disease (CAD).
[003] To restore blood flow through the narrowed or obstructed coronary artery, a minimally invasive procedure such as coronary angioplasty is performed. In the coronary angioplasty, a catheter with a small balloon at its tip is navigated through the vascular system to the site of the blockage. The balloon is then inflated to compress the atherosclerotic plaque against the coronary artery wall, thereby widening the lumen and improving blood flow.
[004] Following balloon angioplasty, there is a risk that the treated coronary artery may recoil or become narrowed again; a process referred to as restenosis. To mitigate this risk, a stent is typically deployed at the treated site.
[005] The stent is an implant inserted into the coronary artery to provide mechanical support. The stent generally has an open or mesh-like tubular structure and is expandable to maintain or re-establish a fluid flow path within the coronary artery. The stent may also be used to treat arterial narrowing or occlusion and to prevent restenosis following a medical procedure such as an angioplasty.
[006] The stent is deployed to prevent premature collapse of a vessel weakened or damaged during angioplasty. However, the healing process post-deployment may trigger a local biological response, including inflammation and smooth muscle cell proliferation, which can lead to neointimal overgrowth or hyperplasia within the stent. This phenomenon, known as restenosis, partially closes the flow path, thereby diminishing or reversing the therapeutic effect of the intervention.
[007] The structural nature of the stent may be permanent or temporary. A permanent stent is typically made of a metallic material. Despite using a biocompatible material, a metallic stent often results in thrombus formation due to the exposure of blood to a foreign surface of the implant. While systemic administration of an antiplatelet agent during or after angioplasty prevents large thrombosis from forming immediately, microscopic thrombosis is frequently present on the metallic stent surface. The early-stage thrombosis may establish a biocompatible matrix that facilitates the adhesion and proliferation of a smooth muscle cell, further contributing to restenosis.
[008] While the metallic stent significantly improves short-term outcomes, it presents a serious long-term complication. Late stent thrombosis remains a critical drawback, occurring months or even years after implantation due to the presence of a foreign body that impairs endothelial healing. Similarly, post-restenosis caused by neointimal hyperplasia and mechanical irritation is a frequent cause of treatment failure. A drug-eluting stent has been developed to control neointimal growth, yet chronic vascular inflammation remains prevalent due to a permanent nature of the metallic stent.
[009] An additional issue in conventional stents is stent malapposition, wherein the stent does not conform adequately to the vessel wall. The stent malapposition can result from anatomical variability or deployment instability. The stent malapposition leads to impaired drug delivery, reduced endothelialization, and elevated risk of thrombus formation. Furthermore, a permanent stent often necessitates long-term administration of a dual antiplatelet therapy (DAPT), which increases the likelihood of a bleeding event and compromises patient adherence and safety.
[0010] A temporary stent (or a bioresorbable stent) is introduced to mitigate the long-term risks by removing the foreign material after the vessel has healed. The biodegradable stent is advantageous in case of recurrent vascular narrowing or a temporary post-surgical condition where long-term support is not required. In such a scenario, the biodegradable stent degrades over time, restoring the natural state of the vessel without leaving a permanent implant. However, current polymeric bioresorbable stent exhibit low mechanical strength and poor ductility, causing early structural failure, stent strut fracture, and elevated thrombosis risk. Such limitations lead to limited clinical adoption and product withdrawal. Furthermore, the polymeric stent is radiolucent, complicating real-time fluoroscopic visualization and hindering optimal placement during an intervention.
[0011] Therefore, there is a need for a stent to overcome the drawbacks of the existing stents.
SUMMARY OF THE INVENTION
[0012] The present invention relates to an interlocking assembly for coupling two stents. In an embodiment, the interlocking assembly includes a plurality of locking elements for coupling a first stent and a second stent. Each locking element includes a first coupling element and a second coupling element. The first coupling element includes a base and a protrusion coupled to the base. The second coupling element includes a groove configured to engage with the base, thereby coupling the first stent and the second stent. The protrusion is disposed outside the groove. At least one first coupling element is provided on the first stent, and at least one second coupling element is provided on the second stent.
[0013] The present disclosure also relates to a hybrid stent. In an embodiment, the hybrid stent includes a first stent, a second stent, and an interlocking assembly (such as, one described above) to lock the first stent and the second stent together.
[0014] 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.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
[0015] 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 instrumentalities disclosed herein. Moreover, those in the art will understand that the drawings are not to scale.
[0016] Fig. 1A depicts a perspective view of a hybrid stent 100 in a collapsed state, according to an embodiment of present disclosure.
[0017] Fig. 1B depicts an enlarged view of the hybrid stent 100 showing an interlocking assembly 400 to couple a first stent 200 and a second stent 300 of the hybrid stent 100, according to an embodiment of the present disclosure.
[0018] Fig. 1C depicts a perspective view of the hybrid stent 100 in an expanded state, according to an embodiment of present disclosure.
[0019] Fig. 2 depicts an anatomical diagram illustrating the hybrid stent 100 implanted in a coronary artery 11 of a patient’s heart, according to an embodiment of present disclosure.
[0020] Fig. 3A depicts a perspective view of the first stent 200 in a collapsed state, according to an embodiment of the present disclosure.
[0021] Fig. 3B depicts a perspective view of the first stent 200 in the expanded state, according to an embodiment of present disclosure.
[0022] Fig. 3C depicts a planar view of the first stent 200 in the expanded state, according to an embodiment of the present disclosure.
[0023] Fig. 4A depicts a top view of a first coupling element 210 provided on the first stent 200, according to an embodiment of the present disclosure.
[0024] Fig. 4B depicts a side view of the first coupling element 210, according to an embodiment of the present disclosure.
[0025] Fig. 5A depicts a perspective view of the second stent 300 in an expanded state, according to an embodiment of the present disclosure.
[0026] Fig. 5B depicts a planar view of the second stent 300 in the expanded state, according to an embodiment of the present disclosure.
[0027] Fig. 6 depicts a top view of a second coupling element 310 provided on the second stent 300, according to an embodiment of the present disclosure.
[0028] Fig. 7 depicts the coupling between the first stent 200 and the second stent 300 in expanded configuration, according to an embodiment of the present disclosure.
[0029] Figs. 8A - 8F depict various stages of coupling the first coupling element 210 with the second coupling element 310, according to an embodiment of the present disclosure.
[0030] Fig. 9A depicts a perspective view of an exemplary stent delivery system 900, according to an embodiment of the present disclosure.
[0031] Fig. 9B depicts an enlarged view of the stent delivery system 900 loaded with the hybrid stent 100 in the expanded state, according to an embodiment of the present disclosure.
[0032] Fig. 9C shows a balloon 906 in the deflated state, with the hybrid stent 100 in the collapsed state, according to an embodiment of the present disclosure.
[0033] Fig. 9D depicts the balloon 906 in the deflated state and the hybrid stent 100 in the crimped state at the target lesion within a coronary artery 11, according to an embodiment of the present disclosure.
[0034] Fig. 9E depicts the balloon 906 in the inflated state and the hybrid stent 100 in the expanded state at the target lesion within the coronary artery 11, according to an embodiment of the present disclosure.
DETAILED DESCRIPTION OF THE INVENTION
[0035] 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.
[0036] 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.
[0037] 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.
[0038] 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.
[0039] In accordance with the present disclosure, a stent interlocking assembly (interchangeably referred to as an interlocking assembly) is disclosed. The stent interlocking assembly is used for coupling two stents with each other. For example, the stent interlocking assembly is particularly useful to couple more than one type of stent in procedures such as interventional cardiology, peripheral vascular interventions, neurovascular procedures, endovascular treatments, minimally invasive vascular surgeries or the like.
[0040] The stent interlocking assembly of the present disclosure includes a plurality of locking elements configured to mechanically couple two stents to form a hybrid stent. In an embodiment, the hybrid stent includes a first stent and a second stent coupled via the stent interlocking assembly. The stent interlocking assembly ensures precise positioning and minimizes stent malapposition. In an embodiment, the first stent includes a metallic or permanent stent, whereas the second stent includes a bioresorbable stent. The metallic stent provides long-term mechanical support, while the bioresorbable stent offers temporary scaffolding. The bioresorbable stent degrades gradually to restore natural vessel anatomy. The progressive degradation of the bioresorbable stent eliminates permanent load of a single device in a dual-stent configuration due to its biodegradable nature, thereby mitigating late thrombosis and chronic inflammation. In some embodiments, at least one of the first and second stents includes a drug-eluting layer for localized therapeutic release. The drug eluting layer promotes endothelial healing and reduces the risk of neointimal hyperplasia.
[0041] The stent interlocking assembly allows for integrated deployment using standard catheterization techniques, simplifying a stent deployment procedure without requiring specialized tools. The combination of a metallic and a bioresorbable stent addresses long-term safety concerns associated with traditional metallic stents while ensuring early-phase mechanical reliability that was lacking in conventional polymeric bioresorbable stents. Thus, the hybrid stent coupled using the stent interlocking assembly improves procedural outcomes, reduces the need for long-term dual antiplatelet therapy, and promotes natural vascular healing. The stent interlocking assembly is applicable across a wide range of vascular anatomies and lesion complexities, making it a versatile and patient-centric solution for a modern cardiovascular intervention.
[0042] Although the interlocking assembly of the present disclosure has been described in the context of coupling a first stent and a second stent for deployment within a coronary artery, it should be considered merely exemplary. The interlocking assembly is also applicable for coupling other intraluminal implants such as a neurovascular scaffold, a peripheral stent, a biliary stent, or the like. The use of the interlocking assembly in such alternative applications is within the scope of the teachings of the present disclosure.
[0043] Now referring to the figures, Figs. 1A-1C depict a hybrid stent 100, according to an embodiment of the present disclosure. The hybrid stent 100 includes at least two stents interlocked together using a stent interlocking assembly 400 (hereinafter, interlocking assembly 400). The interlocking assembly 400 is used for coupling two stents. The hybrid stent 100 may be balloon-expandable or self-expandable. In an embodiment, the hybrid stent 100 is balloon-expandable. In an embodiment, the hybrid stent 100 includes a first stent 200, a second stent 300 and the interlocking assembly 400. The first stent 200 and the second stent 300 have a tubular, mesh-like structure. In one embodiment, the first stent 200 is positioned distally, and the second stent 300 is positioned proximally. However, it should be understood that either stent may be positioned proximally or distally, depending on the clinical application or deployment orientation. In an embodiment, the interlocking assembly 400 is configured to lock the first stent 200 and the second stent 300 together. When the hybrid stent 100 includes more than two stents, multiple instances of the interlocking assembly 400 are provided such that each interlocking assembly 400 couples adjacent two stents together. According to an embodiment, the interlocking assembly 400 comprises a plurality of locking elements 402. The plurality of locking elements 402 is configured to couple the first stent 200 and the second stent 300. Each locking element 402 includes a first coupling elements 210 and a second coupling elements 310. Each first coupling element 210 is configured to engage with a corresponding second coupling element 310 to lock the first stent 200 and the second stent 300 together. Thus, when the first coupling elements 210 are coupled to the respective second coupling elements 310, the first stent 200 and the second stent 300 are securely interlocked with each other. According to an embodiment, at least one first coupling element 210 is provided on the first stent 200 and at least one second coupling element 310 is provided on the second stent 300. For example, all first coupling elements 210 are provided on the first stent 200 and all second coupling elements 310 are provided on the second stent 300. In another example, one or more of the first coupling elements 210 and one or more of the second coupling elements 310 are provided on the first stent 200 and corresponding one or more second coupling elements 310 and corresponding first coupling elements 210 are provided on the second stent 300. The first coupling elements 210 and the second coupling elements 310 are provided at a proximal end, or a distal end or both the proximal and distal ends of the respective stent (e.g., the first stent 200 and the second stent 300) depending on the design and clinical requirements. The positions of the first coupling elements 210 are aligned with the positions of the corresponding second coupling elements 310. In an embodiment, the number of first coupling elements 210 corresponds to the number of second coupling elements 310.
[0044] In an embodiment, the first stent 200 is made of one or more non-bioresorbable materials and the second stent 300 is made of one or more bioresorbable materials. In another embodiment, the first stent 200 is made of one or more bioresorbable materials and the second stent 300 is made of one or more non-bioresorbable materials. As described herein, a bioresorbable material is a material that is capable of being absorbed and/or broken down (or degrade) by bodily fluids a patient’s body and a non-bioresorbable material is a material that are incapable of being absorbed and/or broken down (or degrade) by bodily fluids a patient’s body. In an embodiment, the non-bioresorbable materials include a metal, a metallic alloy, a polymer composite, or combinations thereof. Examples of the non-bioresorbable materials include, without limitation, nitinol, stainless steel, cobalt-chromium alloy, etc. Examples of bioresorbable materials include, without limitation, polylactic acid (PLLA), polyglycolic acid (PGA), magnesium alloys, polycaprolactone (PCL), etc., or combinations thereof. In an example implementation, the first stent 200 is made of a non-bioresorbable material, for example, nitinol, and the second stent 300 is made of a bioresorbable material, for example, polylactic acid (PLLA).
[0045] In an embodiment, each of the plurality of stents of the hybrid stent 100 includes a plurality of struts and a plurality of linkages. The struts are arranged in a plurality of circumferential rows in a pre-defined pattern to form a tubular structure. The plurality of rows of struts is interconnected by at least one linkage to form a plurality of open units and/or a plurality of closed units. The plurality of linkages provides structural support to the hybrid stent 100. The struts are formed using techniques, such as, without limitation, laser cutting, 3-D printing, braiding, welding, machining, etc. or any combination(s) thereof.
[0046] In some embodiments, the first stent 200, or the second stent 300 or both may be coated or treated with a drug-eluting coating to enhance tissue integration and local therapeutic delivery. The drug-eluting coating supports vascular healing while maintaining the mechanical integrity of the hybrid stent 100. The drug-eluting coating is applied to at least a portion of a stent surface, either uniformly or selectively, depending on the intended clinical effect and deployment orientation. The coating is applied to the luminal, abluminal, or both surfaces of the stents (first stent 200 and/or second stent 300) using precision coating techniques such as dip coating, spray coating, electrospinning, plasma-assisted deposition, etc. The drug-eluting coating includes a biocompatible carrier material, such as a bioresorbable or biostable polymer, embedded with one or more therapeutic agents. Suitable polymers for the coating matrix may include, but are not limited to, poly(lactic-co-glycolic acid) (PLGA), polycaprolactone (PCL), polyethylene glycol (PEG), polylactic acid (PLA), polyhydroxybutyrate (PHB), and poly(ethylene-co-vinyl acetate) (PEVA), etc. These polymer coating matrices may further exhibit controlled degradation properties, allowing the drug to be released in a time-dependent, sustained, or biphasic manner. The one or more therapeutic agents may be chosen based upon the intended clinical effect. The drug-eluting coating on the hybrid stent 100 delivers a targeted pharmacological effect that helps regulate the biological response to stent implantation, thereby, minimizing the risk of restenosis and thrombosis.
[0047] In an embodiment, the hybrid stent 100 is intended for intraluminal delivery and deployment, e.g., within a coronary artery, to treat vascular obstructions and provide both temporary and long-term support to wall of the vessel. Fig. 2 depict an anatomical representation of a heart 10 and the hybrid stent 100, according to an embodiment of the present disclosure. In the depicted embodiment, the hybrid stent 100 is deployed within a coronary artery 11 of the heart 10. It should be appreciated that the hybrid stent 100 may be implanted in other vessels (e.g., carotid artery, femoral artery, etc.) of the patient.
[0048] Figs. 3A-3C depict an exemplary first stent 200, according to an embodiment of the present disclosure. The first stent 200 has a mesh-like, tubular structure extending between a proximal end 200a and a distal end 200b, thereby defining a longitudinal length of the first stent 200.
[0049] The first stent 200 may have a uniform or non-uniform diameter across its length. In one embodiment, the first stent 200 has a uniform diameter, as shown in Fig. 3A. In another embodiment, the first stent 200 has a tapered profile, i.e., a diameter of the first stent 200 gradually reduces from the proximal end 200a to the distal end 200b or vice versa. Optionally, the first stent 200 may be flared at the proximal end 200a and/or the distal end 200b. The first stent 200 is balloon expandable or self-expandable. In an embodiment, the first stent 200 is balloon expandable. In an embodiment, the first stent 200 is made of a non-bioresorbable material, for example, nitinol. Additionally, or optionally, an outer surface of the first stent 200 is coated with bioresorbable polymer composites to enhance biocompatibility and therapeutic performance of the first stent 200. Examples of materials for the coating include, without limitation, Poly(N-isopropylacrylamide) (PNIPAM) combined with silica nanoparticles, polyurethane reinforced with carbon nanotubes or glass fibers, chitosan-based hydrogels reinforced with montmorillonite clay, etc.
[0050] The first stent 200 is configured to toggle or transition between a radially collapsed state (interchangeably referred to as the collapsed or crimped state) and a radially expanded state (interchangeably referred to as the expanded state). For example, the first stent 200 may be crimped to the collapsed state using a loading device (not shown), to load the first stent 200 over a delivery device (not shown). The loading device may be any device known in the art capable of crimping a stent. Upon delivering the first stent 200 to an intended zone, the first stent 200 is configured to radially expand from the collapsed state to the expanded state. In an embodiment, the first stent 200 is mounted over a balloon in a crimped state and is radially expanded by inflating the balloon. In the collapsed state, the first stent 200 has a reduced a radial profile, making it suitable for minimal invasive delivery. The collapsible nature of the first stent 200 allows it to be crimped to a reduced profile, enabling smooth passage through narrow vasculature. The first stent 200 expands to adapt and anchor with the wall of the aortic vessel without compromising its mechanical strength and structural integrity.
[0050] The first stent 200 is dimensioned according to clinical requirements, for example, depending upon a diameter of a body cavity (such as the coronary artery 11) in which the first stent 200 is deployed. The first stent 200 has a predefined length and a predefined diameter. In the collapsed state, the first stent 200 may have a predefined collapsed length ranging between 8 mm and 48 mm. In the expanded state, the first stent 200 may have a predefined expanded length ranging between 8 mm and 38 mm. In an embodiment, the collapsed length and the expanded length of the first stent 200 are 28 mm and 24 mm, respectively. In the collapsed state, the first stent 200 includes a collapsed diameter ranging from 0.8 mm to 1.4 mm. In the expanded state, the first stent 200 has an expanded diameter ranging from 2.0 mm to 4.5 mm. In an embodiment, the collapsed diameter and the expanded diameter are 1.2 mm and 3.5 mm, respectively. According to an embodiment, the expanded diameter of the first stent 200 remains the same throughout a predefined length of the first stent 200.
[0051] The first stent 200 is formed using techniques, such as, without limitation, laser cutting, 3-D printing, braiding, welding, machining, etc. In an embodiment, the first stent 200 is formed by laser cutting a tube of a desired material (e.g., nitinol) to form the mesh structure.
[0052] In an embodiment, the first stent 200 includes a plurality of circumferentially extending rows 232 (or rows 232) of a first struts 230 (hereinafter, struts 230). The struts 230 have a predefined profile such as curved, straight, wavy, etc. In an embodiment, the struts 230 have a curved profile. The struts 230 are connected in a predefined pattern, such as, curved chevron pattern, zig-zag pattern, chevron pattern, etc., to form alternating peaks 230a and troughs 230b. In other word, the first struts 230 are interconnected to form alternating peaks 230a and troughs 230b. In an embodiment, the strut 230 are connected in curved chevron pattern. For example, the struts 230, when connected, have a shape similar to a cuspidate shape of an apex of a leaf. Dimensions of the struts 230 may be chosen based upon clinical requirements. The dimensions of the struts 230 may be the same or different. In an embodiment, the length of the struts 230 may range from 0.3 mm to 0.8 mm, the width of the struts 230 may range from 0.08 mm to 0.15 mm, and the thickness of the struts 230 may range from 0.08 mm to 0.14 mm. In an embodiment, the length, width and thickness of the struts 230 are 0.6 mm, 0.1 mm, and 0.1 mm, respectively.
[0053] The rows 232 are arranged axially between the proximal end 200a and the distal end 200b of the first stent 200. Each row 232 of the first struts 230 extends circumferentially. The pluralities of rows 232 are coupled in a predefined pattern to form a tubular structure of the first stent 200. The first stent 200 includes a plurality of linkages. The plurality of linkages is configured to interconnect two adjacently disposed rows 232. The plurality of linkages couples the plurality of rows 232 in a predefined pattern to form a tubular structure of the first stent 200. In an embodiment, the plurality of linkages of the first stent 200 includes a plurality of first linkages 217 (hereinafter, first linkages 217) and a plurality of second linkages 220 (hereinafter, second linkages 220).
[0054] In an embodiment, the first linkages 217 couple at least one pair of adjacently disposed rows 232 such that the first stent 200 includes at least one row 203 of closed units 201 at each of the proximal end 200a and distal end 200b. A plurality of rows 203 of closed units 201 or a plurality of rows 207 of open units 205 or combinations thereof disposed between the at least one row 203 provided at the proximal end 200a and the distal end 200b. Each first linkage 217 is configured to couple a trough 230b of a first row 232a of the pair of adjacently disposed rows 232 with a corresponding peak 230a of a second row 232b of the pair of adjacently disposed rows 232 to form one closed unit 201.
[0055] In an embodiment, the plurality of first linkages 217 coupling alternate pairs of adjacently disposed rows 232 such that the first stent 200 includes the plurality of rows 203 of closed units 201 and the plurality of rows 207 of open units 205 disposed alternatingly between the proximal end 200a and the distal end 200b as shown in Fig. 3C. Each row 203 of the closed units 201 and each row 207 of open units 205 extend circumferentially. For example, struts 230 of the pair of adjacently dispose rows 232 are coupled using the first linkages 217. According to an embodiment, each first linkage 217 is configured to couple each trough 230b of the first row 232a of the pair of adjacently disposed rows 232 is coupled to a corresponding peak 230a of a second row 232b of the pair of adjacently disposed rows 232 by the first linkage 217 to form the closed units 201. Each closed unit 201 has a pre-defined shape like hexagonal, diamond-shaped, etc. In an embodiment, the closed unit 201 has a hexagonal shape. In the embodiment depicted herein, one row 203 of closed units 201 is provided at both the proximal end 200a and the distal end 200b of the first stent 200. In an embodiment, each closed unit 201 includes four struts 230 and two first linkages 217 forming an apex 201c at each of proximal and distal ends of the closed unit 201.
[0056] It should be understood that the coupling between the rows 232 as depicted herein is merely exemplary and the rows 232 is coupled in various other configurations based upon clinical requirements. In an embodiment, the rows 232 are connected such that the first stent 200 includes at least one row 203 of closed unit 201 at both the proximal end 200a and the distal end 200b, and a plurality of rows 203 of closed units 201 or a plurality of rows 207 of open units 205 or combinations thereof provided between the said at least one row 203a at the proximal end 200a and the distal end 200b. For example, the first stent 200 includes only the rows 207 of open units 205 between the said at least one row 203a at the proximal end 200a and the distal end 200b. In another example, the first stent 200 includes only the rows 203 of closed units 201 between the said at least one row 203a at the proximal end 200a and the distal end 200b, i.e., in this case, the first stent 200 includes the rows 203 of closed units along its entire length. Other variations are also possible and the same is within the scope of the present disclosure.
[0057] The dimensions of the closed units 201 and the open units 205 are uniform or non-uniform depending on the desired design. In an embodiment, the dimensions of the closed units 201 and the open units 205 are the same. For example, the width of the closed units 201 and the open units 205 may range from 0.08 mm to 0.15 mm. In an embodiment, the width of the closed units 201 and the open units 205 is 0.10 mm. Further, for example, the axial length of the closed units 201 and the open units 205 may range from 0.25 mm to 0.8 mm. In an embodiment, the axial length of the closed units 201 and the open units 205 is 0.6 mm.
[0058] The first linkages 217 are configured to couple the pairs of adjacently disposed rows 203 to form the closed units 201. The first linkages 217 extend in an axial direction. The first linkage 217 may have a predefined shape including, but not limited to, straight, curved, angled, s-shaped, diamond shaped, zigzag, etc. In one embodiment, the first linkage 217 is straight, thus, forming hexagonal closed units 201, as shown in Fig. 3B. The first linkages 217 allow uniform expansion of the first stent 200 during the deployment. The first linkages 217 also help the first stent 200 to conform to the coronary artery 11. Dimensions of the first linkages 217 are chosen based upon clinical requirements. The first linkages 217 may have the same or different dimensions. In an embodiment, the first linkages 217 have the same dimensions. The length, width and thickness of the first linkages 217 may range from 0.3 mm to 0.9 mm, from 0.07 mm to 0.12 mm, and from 0.07 mm to 0.12 mm, respectively. In an embodiment, the length, width and thickness of the first linkages 217 are 0.6 mm, 0.10 mm, and 0.10 mm, respectively.
[0059] In an embodiment, the second linkages 220 are configured to couple at least one pair of adjacently disposed rows 203 of closed units 201, for example, pairs of adjacently disposed rows 203 of closed units 201 having one or more rows 207 of open units 205 therebetween. In other words, each second linkage 220 is configured to couple a first closed unit 201a of a first row 203b of a pair of adjacently disposed rows 203 of closed units 201 to a second closed unit 201b of a second row 203c of the pair of adjacently disposed rows 203 of closed units 201. The pair of adjacently disposed rows 203 of closed units 201 has one or more rows 207 of the plurality of rows 207 of open units 205 therebetween. In one embodiment, the second linkages 220 are coupled to a respective apex 201c of the first and second closed units 201a, 201b. In one embodiment, the pairs of adjacently disposed rows 203 of closed units 201 are coupled in a circumferentially offset manner, i.e., first closed unit 201a and the second closed unit 201b are circumferentially offset. For example, the first closed unit 201a and the second closed units 201b are circumferentially offset by a distance equal to the width of one closed unit 201 as depicted in Fig. 3C. It is possible that the first and second closed units 201a, 201b may be circumferentially offset by a distance equal to multiples of the width more than one closed unit 201. In an embodiment, the pairs of adjacently disposed rows 203 are coupled in an axially aligned manner, i.e., the first closed unit 201a and the second closed unit 201b are axially aligned. All or a subset of the closed units 201 of the pairs of adjacently disposed rows 203 may be coupled using the second linkages 220 in a manner as disclosed herein. In an embodiment, every third of the closed units 201 of the pairs of adjacently disposed rows 203 are coupled using the second linkage 220 as shown in Fig. 3C. Other configurations of coupling the first and second closed units 201a, 201b of the pair of adjacent rows 203 using the second linkage 220 are possible, such as diagonal interconnection or rotationally offset, depending on requirements and the same is within the scope of the present disclosure.
[0060] The second linkages 220 may be a straight, curved, angled, s-shaped, diamond shaped, Zigzag, etc. In the depicted embodiment, the second linkages 220 are S-shaped. The S-shaped geometry of the second linkage 220 enables the formation of uniformly distributed open units 205 and supports the flexible configuration of expandable first stent 200. The dimensions of the second linkages 220 may be chosen based upon clinical requirements and desired performance of the first stent 200.
[0061] According to an embodiment, the first coupling elements 210 are provided on the first stent 200 as shown in Figs. 3A – 3C. In an embodiment, the first coupling elements 210 are provided at both, the proximal end 200a and the distal end 200b of the first stent 200. In an embodiment, the first coupling element 210 are integrally coupled to the first stent 200. For example, a single tube of a desired material, e.g., nitinol, is laser cut to form the first stent 200 and the first coupling elements 210. However, in other embodiments, the first coupling element 210 may be separate components coupled to the first stent 200 using a suitable technique, for example, laser welding, micro-welding, crimping, adhesive bonding, or mechanical interlocking, depending on the material compatibility and clinical application.
[0062] In one embodiment, the first coupling elements 210 are configurable between an open configuration and a folded configuration. Fig. 4A depicts a top view of one first coupling element 210 in an open configuration and Fig. 4B depicts a side view of the first coupling element 210 in a folded configuration, according to an embodiment of the present disclosure. As depicted in Fig. 4B, in one embodiment, each of the at least one first coupling element 210 is provided at the apex 201c of the corresponding closed unit 201 at the proximal end 200a or the distal end 200b. The number of first coupling elements 210 are chosen based upon the deployment scenario, mechanical requirements, desired strength for the hybrid stent 100, designs of the first stent 200 and the second stent 300, desired stress resilience, and so forth. In an example implementation, six first coupling elements 210 are provided at each of the proximal end 200a and the distal end 200b of the first stent 200. In one embodiment, the first coupling elements 210 are provided on the apex 201c of every n-th (e.g., third) closed unit 201 at the proximal end 200a and/or the distal end 200b. The exact spacing may vary based on mechanical requirements and alignment with the second coupling elements 310.
[0063] The first coupling element 210 includes a first end 210a and a second end 210b. The first end 210a of the first coupling element 210 is coupled to the first stent 200. According to an embodiment, the first coupling element 210 includes a base 210c provided at the first end 210a and a protrusion 210d coupled to the base 210c and provided at the second end 210b. The base 210c extends away from the first stent 200, for example, from the corresponding closed unit 201, in an axial direction.
[0064] The base 210c has a predefined shape, such as rectangular, square, trapezoidal, elliptical, etc. In an embodiment, the base 210c is generally trapezoidal with curved lateral sides. The base 210c has a first width (W1) and a first length (L1). The dimensions of the base 210c are designed based upon requirements. In an embodiment, the first width W1 ranges from 0.05 mm to 0.20 mm, and the first length L1 ranges from 0.10 mm to 0.50 mm. W1 and L1 correspond to a maximum lateral width and a maximum axial length of the base 210c. In an example implementation, W1 and L1 are 0.10 mm and 0.30 mm, respectively.
[0065] The protrusion 210d projects away from the base 210c. The protrusion 210d has a predefined shape such as, but not limited to, diamond shape, C-shape, crown shape, U shape, O-shape, oval shape, rectangular, trapezoidal, etc. In an embodiment, the protrusion 210d has a generally circular shape. The protrusion 210d may also include a tapered or rounded tip to facilitate atraumatic engagement during deployment and minimize vessel injury.
[0066] In an embodiment, the protrusion 210d is elastically deformable. For example, the protrusion 210d is foldable along a longitudinal axis X of the first coupling element 210 to a folded configuration. In other words, lateral sides of the protrusion 210d are movable toward each other along the longitudinal axis X of the first coupling element 210. Upon release, the elastic property of the protrusion 210d causes it to return to its original shape, i.e., open configuration. The protrusion 210d includes a second width W2 and a second length L2. W2 corresponds to a maximum lateral width and L2 corresponds to a maximum axial length of the protrusion 210d. The second width W2 is greater than the first width W1 of the base 210c. This dimensional difference assists in engagement with the corresponding second coupling element 310. In an embodiment, the second width W2 ranges from 0.40 mm to 0.80 mm, and the second length L2 ranges from 0.30 mm to 0.70 mm. In an example, W2 and L2 are 0.60 mm and 0.50 mm, respectively.
[0067] Additionally, or optionally, the protrusion 210d includes an aperture 212. In an embodiment, the aperture 212 is provided centrally. The aperture 212 is provided to reduce structural weight of the first coupling element 210. The aperture 212 also enhances flexibility during engagement of the first stent 200 with the second stent 300. The aperture 212 has a predefined shape, such as, but not limited to, circular, triangular, ellipse, square, rectangle, polygonal, etc. In an embodiment, the aperture 212 has a circular shape.
[0068] In an embodiment, the first coupling element 210 includes a connecting portion 210e that couples the base 210c and the protrusion 210d. The connecting portion 210e is disposed between the base 210c and the protrusion 210d. The connecting portion 210e provides a transition from the base 210c to the protrusion 210d and imparts strength. In an embodiment, the connecting portion 210e has a trapezoidal shape with curved lateral sides, though it may have any other shape. The connecting portion 210e has a predefined length, for example, ranging from 0.05 mm to 0.15 mm. In an example implementation, the connecting portion 210e has a length of 0.10 mm.
[0069] In an embodiment, the first coupling element 210 is made of the same material as that of the corresponding stent (in this example, the first stent 200) that the first coupling element 210 is provided on. In an embodiment, the first coupling element 210 is made of one or more non-bioresorbable materials including, without limitation stainless steel (316L), cobalt-chromium alloy, platinum-chromium alloy, or a combination thereof. In an example, the first coupling element 210 is made of nitinol.
[0070] Fig. 5A- Fig. 5B depict an exemplary second stent 300, according to an embodiment of the present disclosure. In the depicted embodiment, the second stent 300 includes a proximal end 300a and a distal end 300b, thereby defining a length therebetween. The second stent 300 is configured to transition or toggle between the collapsed state and the expanded state. In the collapsed state, the second stent 300 is crimped, reducing a radial profile of the second stent 300, thereby making it suitable for minimal invasive delivery. The collapsible nature of the second stent 300 allows it to be crimped to a reduced profile, enabling smooth passage through narrow vasculature. In the expanded state, the second stent 300 conforms to the wall of coronary artery 11, providing structural support without compromising flexibility. In the collapsed state, the second stent 300 has a collapsed diameter. In the expanded state, the second stent 300 has an expanded diameter. In an embodiment, the second stent 300 is mounted over a balloon in a crimped state and is radially expanded by inflating the balloon.
[0071] The second stent 300 may have a uniform or non-uniform diameter along its length. In one embodiment, the second stent 300 has a uniform diameter, as shown in Fig. 5A. In another embodiment, the second stent 300 has a tapered profile, i.e., a diameter of the second stent 300 gradually reduces from the proximal end 300a to the distal end 300b or vice versa. Optionally, the second stent 300 may be flared at the proximal end 300a and/or the distal end 300b. The second stent 300 may be balloon expandable or self-expandable. In an embodiment, the second stent 300 is balloon expandable.
[0072] The second stent 300 is dimensioned according to clinical requirements. The second stent 300 has a predefined length and a predefined diameter. In the collapsed state, the second stent 300 may have a predefined collapsed length ranging between 8 mm and 20 mm. In the expanded state, the second stent 300 may have a predefined expanded length ranging between 10 mm and 24 mm. In an embodiment, the collapsed length and the expanded length of the second stent 300 are 16 mm and 20 mm, respectively. In the collapsed state, the second stent 300 includes a collapsed diameter ranging from 0.8 mm to 1.5 mm. In the expanded state, second stent 300 has an expanded diameter ranging from 2.5 mm to 4.0 mm. In an embodiment, the collapsed diameter and the expanded diameter are 1.2 mm and 3.0 mm, respectively.
[0073] The second stent 300 is formed using techniques, such as, without limitation, laser cutting, 3-D printing, braiding, welding, machining, etc. In an embodiment, the second stent 300 is formed using laser cutting.
[0074] In an embodiment, the second stent 300 includes a plurality of rows 332 (or rows 332) of second struts 330 (hereinafter, struts 330). Each row 332 extends circumferentially. The rows 332 are arranged axially between the proximal end 300a and the distal end 300b. The struts 330 have a predefined profile such as curved, straight, wavy, etc. In an embodiment, the struts 330 have a straight profile. Dimensions of the struts 330 may be chosen based upon clinical requirements. The dimensions of the struts 330 may be the same or different. In an embodiment, all struts 330 of the second stent 300 have the same dimensions. In an embodiment, the length of the struts 330 may range from 0.4 mm to 1.5 mm, the width of the struts 330 may range from 0.05 mm to 0.12 mm, and the thickness of the struts 330 may range from 0.08 mm to 0.15 mm. In an embodiment, the length, width and thickness of the struts 330 are 1.0 mm, 0.08 mm, and 0.10 mm, respectively.
[0075] The rows 332 are coupled in a pre-defined pattern to form a tubular structure of the second stent 300. In an embodiment, the rows 332 are coupled using a plurality of third linkages 320a and a plurality of fourth linkages 320b to form a plurality of first rows 303 of first closed units 301 and a plurality of rows 307 of second closed units 305 as explained below.
[0076] In an embodiment, the second stent 300 includes a proximal section 302a disposed at the proximal end 300a, a distal section 302b disposed at the distal end 300b and a middle section 302c disposed between the proximal section 302a and the distal section 302b. The proximal section 302a includes at least one first row 303 of first closed units 301 and the distal section 302b includes at least one first row 303 of first closed units 301. The number of first rows 303 in the proximal section 302a and the distal section 302b are chosen based upon clinical requirements. In an embodiment, the second stent 300 includes a proximal row 303a of first closed units 301 provided at the proximal end 300a of the second stent 300, a distal row 303b of the first closed units 301 provided at the distal end 300b of the second stent 300, and a plurality of second rows 307 of second closed units 305 extending coaxially between the proximal row 303a and the distal row 303b. The first closed units 301 have a predefined shape such as diamond, hexagonal etc. In an embodiment, the first closed units 301 have a diamond shape as shown in Fig. 5B. Each first closed unit 301 defines an enclosed structure. In an embodiment, each first closed unit 301 is formed by interconnecting two struts 330 each from a pair of adjacently disposed first rows 332 using two oppositely disposed third linkages 320a. These form a diamond-like configuration as shown in Fig. 5B.
[0077] Each second row 307 extends circumferentially. The number of second rows 307 are chosen based upon clinical requirements. In an embodiment, the second stent 300 includes six second rows 307. The second closed units 305 defined an enclosed structure and have a predefined shape such as diamond, hexagonal, etc. In an embodiment, each second closed unit 305 resembles the shape of “8” as shown in Fig. 5B. In an embodiment, each second closed unit 305 is formed by interconnecting two struts 330 each of four adjacently disposed rows 332 coupled using one third linkage 320a and one fourth linkage 320b (e.g., at the second row 307 adjacent to the proximal row 303a and the distal row 303b) or two fourth linkages 320b (at the remaining second rows 307). In other words, in an embodiment, each second closed unit 305 includes eight struts 330 and a pair of fourth linkages 320b or eight struts 330, one third linkage 320a and one fourth linkage 320b. Each second closed unit 305 includes a first portion 305a and a second portion 305b. The first portion 305a is disposed towards the proximal end 300a and the second portion 305b is disposed towards the distal end 300b. Though the first closed unit 301 and the second closed unit 305 are shown to have different shapes, it is possible that they have the same shape.
[0078] The first rows 303 and the second rows 307 are arranged and coupled in a pre-defined pattern. In an embodiment, the second rows 307 are axially aligned with each other and with the first rows 303. The first rows 303 and the second rows 307 are coupled using a plurality of linkages. In an embodiment, the second stent 300 includes the plurality of third linkages 320a, the plurality of fourth linkages 320b, a plurality of fifth linkages 320c, and a plurality of sixth linkages 320d.
[0079] The third linkages 320a are configured to couple the first closed units 301, the second closed units 305, or both. In an embodiment, each of the plurality of third linkages 320a couples at least one first closed unit 301 of the proximal row 303a or the distal row 303b with a corresponding second closed unit 305 of an adjacently disposed second row 307.
[0080] In an embodiment, at least one pair of second closed units 305 adjacently disposed in axial direction (for example, all such pairs) are coupled using one fourth linkage 320b. For example, each of the plurality of fourth linkages 320b is configured to couple at least one second closed unit 305 of one second row 307 with a corresponding second closed unit 305 of an adjacently disposed second row 307.
[0081] According to an embodiment, at least one pair of second closed units 305 adjacently disposed in circumferential direction (e.g., all such pairs) are coupled using at least one fifth linkage 320c. For example, the plurality of fifth linkages 320c are configured to couple at least one second closed unit 305 of one row 307 with an adjacently disposed second closed unit 305 of the same row 307. In other words, the fifth linkages 320c couple at least one pair of adjacently disposed second closed units 305 in a circumferential direction within a same second row 307. According to an embodiment, each fifth linkage 320c couples one second closed unit 305 of one second row 307 with an adjacently disposed second closed unit 305 of the same second row 307. In an embodiment, second portions 305b of the pair of second closed units 305 adjacently disposed in circumferential direction are coupled using fifth linkage 320c. Alternately, or in addition, the first portions 305a of such pairs may be coupled in a similar manner using one fifth linkage 320c.
[0082] In an embodiment, the plurality of sixth linkages 320d are configured to couple at least one first closed unit 301 of the proximal row 303a with an adjacently disposed first closed unit 301 of the proximal row 303a and/or to couple at least one first closed unit 301 of the distal row 303b with an adjacently disposed first closed unit 301 of the distal row 303b. In other words, the sixth linkages 320d couple at least one pair of adjacently disposed first closed units 301 of the proximal row 303a and/or couple one pair of adjacently disposed first closed units 301 of the distal row 303b. According to an embodiment, each first closed unit 301 of the proximal row 303a is coupled to an adjacently disposed first closed unit 301 of the proximal row 303a using one sixth linkage 320d. In an embodiment, the first closed units 301 of the distal row 303b are not interconnected, i.e., the first closed units 301 of the at least one first row 303 in the distal section 302b are discontinuous. Other variations are also within the scope of the present disclosure. For example, in an embodiment, circumferentially adjacent first closed units 301 of the distal row 303b are coupled using the sixth linkages 320d, while the circumferentially adjacent first closed units 301 in the proximal row 303a are coupled using the sixth linkages 320d. In another embodiment, the circumferentially adjacent first closed units 301 of the distal row 303b are coupled using the sixth linkages 320d, while the circumferentially adjacent first closed units 301 in the proximal row 303a are not interconnected (i.e., they are discontinuous). In yet another embodiment, the circumferentially adjacent first closed units 301 in both, the proximal row 303a and the distal row 303b, are not interconnected, i.e., they are discontinuous.
[0083] The third linkages 320a have a predefined shape, including, but not limited to, straight, curved, angled, s-shaped, diamond shape, zigzag, rectangular etc. In one embodiment, the third linkages 320a have rectangular shape having a predefined length ranging from 0.20 mm to 0.60 mm and a predefined width ranging from 0.05 mm to 0.15 mm. In an embodiment, the length and width of the third linkages 320a are 0.40 mm and 0.10 mm, respectively.
[0084] The plurality of linkages, including the third linkages 320a, the fourth linkages 320b, the fifth linkages 320c and the sixth linkages 320d, contribute to the radial strength of the second stent 300. Though the third linkages 320a are depicted to have the same shape and dimensions, it is possible that the third linkages 320a are designed different shapes and/or dimensions based upon requirements. In an embodiment, the fourth linkage 320b, the fifth linkage 320c and the sixth linkage 320d are similar to the third linkage 320a. Accordingly, their structure can be referred to from that of the third linkage 320a and is not repeated for the sake of brevity.
[0085] It should be noted that the specific designs and configurations of the first stent 200 and second stent 300 described in the present disclosure are exemplary and are provided for illustrative purposes only. Various modifications or alternative stent designs may be employed by a person skilled in the art.
[0086] In an embodiment, the second coupling elements 310 are provided on the second stent 300. The second coupling elements 310 is positioned at the proximal end 300a and/or the distal end 300b of the second stent 300, for example, each of the at least one second coupling elements 310 are provided on one or more third linkages 320a at the proximal end 300a and/or the distal end 300b. In other words, each of the at least one second coupling element 310 is provided on the third linkages 320a of the first closed unit 301 of the proximal row 303a or the distal row 303b. According to an exemplary embodiment, at least one second coupling element 310 is provided on the third linkage 320a at the distal end 300b. In one embodiment, the second coupling elements 310 are integrally formed with the second stent 300. For example, the second stent 300 and the second coupling elements 310 are formed by laser cutting a tube of a desired material. However, in other embodiments, the second coupling element 310 may be separate components coupled to the second stent 300 using a suitable technique, for example, laser welding, micro-spot welding, mechanical crimping, biocompatible adhesive bonding, etc.
[0087] Fig. 6 depicts a top view of one second coupling element 310, according to an embodiment of the present disclosure. In an embodiment, the second coupling element 310 is provided on the second stent 300, for example, on the third linkage 320a of a respective first closed unit 301 of the second stent 300. In an example implementation, one second coupling element 310 is provided at the third linkage 320a at each first closed unit 301 at the distal end 300b of the second stent 300.
[0088] Each second coupling element 310 has a predefined geometry that facilitates secure mechanical interlock with the respective first coupling element 210. The second coupling element 310 extends away from second stent 300, for example, from the respective first closed unit 301, in an axial direction.
[0089] In an embodiment, each second coupling element 310 includes a groove 310a that defines a receiving region for a corresponding portion of the corresponding first coupling element 210. In an embodiment, the groove 310a is configured to engage with the base 210c of the corresponding first coupling element 210, thereby coupling the first stent 200 and the second stent 300. In an embodiment, at least a portion of the base 210c is disposed within the groove 310a. For example, a first portion 210c1 of the base 210c resides in the groove 310a and a second portion 210c2 of the base 210c resides on a boundary portion 310b of the second coupling element 310 as shown in Fig. 8F. In other words, the first portion 210c1 of the base 210c is disposed within the groove 310a and the second portion 210c2 of the base 210c is disposed outside the groove 310a. The first portion 210c1 and the second portion 210c2 are provided towards the first end 210a and the second end 210b of the first coupling element 210, respectively. Further, the protrusion 210d, and optionally, the connecting portion 210e, reside outside the groove 310a. The groove 310a has a predefined shape, such as, but not limited to, circular, triangular, ellipse, square, rectangle, polygonal, etc. In an embodiment, the groove 310a has a rectangular shape. The internal dimensions of groove 310a are selected such that, upon engagement with the first coupling element 210, it ensures tight fitting and resistance to disengagement. The groove 310a has a third width (W3) and a third length (L3). The first width (W1) of the base 210c of the first coupling element 210 is less than or equal to the third width (W3) of the groove 310a of the corresponding second coupling element 310, and the second width (W2) of the protrusion 210d of the first coupling element 210 is greater than the third width (W3) of the groove 310a. Due to the second width (W2) being greater than the third width W3 of the groove width, the first coupling element 210 forms a positive mechanical interference with the second coupling element 310 once the protrusion 210d of the first coupling element 210 is inserted through the groove 310a of the second coupling element 310. This dimensional mismatch between the groove 310a and the protrusion 210d ensures that the protrusion 210d cannot pass through the groove 310a unless the protrusion 210d is folded via an external force, thereby ensuring that the first coupling element 210 and the second coupling element 310 remain securely coupled to each other. Consequently, the locking element 402 disclosed herein prevents unwanted disengagement under physiological forces or mechanical disturbances during or after deployment, and securely couples the first stent 200 and the second stent 300. In an embodiment, the third width W3 ranges from 0.1 mm to 0.5 mm, and the third length L3 ranges from 0.2 mm to 1.0 mm. In an example, W3 and L3 are 0.3 mm and 0.6, mm, respectively.
[0090] In an embodiment, the second coupling element 310 is made of the same material as that of the respective stent (the second stent 300 in the example shown herein) that the second coupling element 310 is provided on. In an embodiment, the second coupling element 310 is made of one or more bioresorbable materials, including without limitation, poly-L-lactic acid (PLLA), poly-D,L-lactide-co-glycolide (PLGA), magnesium alloy, or a combination thereof. In an example, the second coupling element 310 is made of poly-L-lactic acid (PLLA).
[0091] Fig. 7 illustrates coupling of the first coupling elements 210 with the corresponding second coupling elements 310, according to an embodiment of the present disclosure. In the interlocked configuration (i.e., when the first and second coupling elements 210, 310 are coupled or engaged to each other), the groove 310a of each second coupling element 310 is configured to receive a portion of a corresponding closed unit 201 of the first stent 200, and the protrusion 210d of each first coupling element 210 is disposed within a corresponding first closed unit 301 of the second stent 300 according to one embodiment, enhancing positional locking and restricting relative movement under mechanical stress.
[0092] An embodiment of a process for coupling the first stent 200 and the second stent 300 with the help of the interlocking assembly 400 is now explained with reference to Fig. 8A to Fig. 8F. For reasons of clarity, only one locking element 402 including one first coupling element 210 and the corresponding second coupling element 310 is illustrated. According to an embodiment, the first coupling element 210 and the second coupling element 310 are coupled using a snap-fit technique. In this exemplary scenario, the first coupling element 210 is provided on the first stent 200 and the second coupling element 310 is provided on the second stent 300. In an embodiment, the first stent 200 and the second stent 300 are interlocked during the pre-deployment assembly stage, before crimping and loading the hybrid stent 100 into a delivery catheter. As shown in Fig. 8A, the process begins with the axial alignment of the first coupling element 210 of the first stent 200 and the second coupling element 310 of the second stent 300. The first coupling element 210 is directed toward the corresponding second coupling element 310.
[0093] The first coupling element 210 is advanced toward the second coupling element 310 such that the protrusion 210d is introduced into the groove 310a as illustrated in Fig. 8B. In an embodiment, the protrusion 210d folds inward automatically along the longitudinal axis X during insertion due to its flexible and deformable design. The self-deformation of the protrusion 210d results in reducing its cross-sectional profile temporarily to facilitate a smooth passage through the narrower groove 310a of the second coupling element 310 despite the second width W2 of the protrusion 210d being greater than the third width W3 of the groove 301a without a need for manual pre-folding or for any specialized instrument to fold the protrusion 210d. Figs. 8C-8E illustrate successive stages during the insertion of the protrusion 210d through the groove 310a. The protrusion 210d is continued to be inserted until the protrusion 210d is disposed outside the groove 310a as depicted in Fig. 8E.
[0094] At this stage, the protrusion 210d is released. Due to its elastic characteristics, the protrusion 210d returns to its original shape, thereby interlocking the first coupling element 210 with the second coupling element 310. Fig. 8F depicts the interlocked configuration of the locking element 402, i.e., of the first coupling element 210 and the second coupling element 310, according to an embodiment. Thus, a snap-fit engagement is formed between the first coupling element 210 and the second coupling element 310. In the interlocked configuration, at least a portion (e.g., the first portion 210c1) of the base 210c remains inside the groove 310a. The connecting portion 210e is disposed outside the groove 310a and resides on or under the boundary portion 310b. For example, the connecting portion 210e resides on the boundary portion 310b as shown in Fig. 8F. The groove 310a and the protrusion 210d are dimensioned (through respective widths) such that the protrusion 210d retains its width unless an external trigger (e.g., a force folding the protrusion 210d) is applied, thereby preventing unintended disengagement during crimping, delivery, or deployment, and post-deployment into the vessel. The pre-assembled hybrid stent 100 can be crimped and loaded onto a delivery system. The first coupling elements 210 and the second coupling elements 310 together form a passive, mechanical, and secure stent interlocking assembly 400. The snap-fit locking mechanism described herein provides an easier way to assemble the first stent 200 and the second stent 300, reducing the time for assembly and enhancing procedural efficiency.
[0095] Figs. 9A and 9C illustrate an exemplary stent delivery system 900 for deploying the hybrid stent 100, according to an embodiment of the present disclosure. The stent delivery system 900 is a balloon-expanded delivery system configured to deliver and deploy the hybrid stent 100 at a target vascular site such as the aortic vessel. The stent delivery system 900 includes a handle 902 at a proximal end 900a of the stent delivery system 900 and an elongated catheter shaft 904 coupled to the handle 902 and extending toward a distal end 900b of the stent delivery system 900. The stent delivery system 900 further includes a balloon 906, a sensor 908, and a sensor sheath 910 towards the distal end 900b. The balloon 906 is coupled to the catheter shaft 904 towards a distal end of the catheter shaft 904. The balloon 906 is configurable to be in a deflated state and an inflated state.
[0096] The handle 902 is ergonomically designed for medical practitioners. In an embodiment, the handle 902 includes components such as a luer lock fitting for guidewire access and an inflation port 902a. The inflation port 902a is configured to couple with an inflation device (not shown). The balloon 906 is fluidically coupled to the inflation port 902a, for example, via an inflation lumen of the catheter shaft 904. The inflation device is configured to deliver a pressurized inflation fluid (e.g., a saline solution having a contrast dye) into a balloon lumen of the balloon 906, enabling radial expansion of the balloon 906 and corresponding deployment of the hybrid stent 100 at the target site. In an embodiment, the inflation device is a syringe, though any other known inflation device may be used.
[0097] The hybrid stent 100 is mounted on the balloon 906 in a crimped configuration. The hybrid stent 100 may be crimped using any known crimping and/or loading device. In an embodiment, the hybrid stent 100 is mounted in a pre-assembled state, i.e., the first stent 200 and the second stent 300 are locked using the interlocking assembly 400 (as explained earlier) before crimping the hybrid stent 100 on the balloon 906. Fig. 9C shows the balloon 906 in the deflated state, with the hybrid stent 100 securely loaded over its outer surface in the crimped state. Fig. 9B shows the balloon 906 in the inflated state and correspondingly, the hybrid stent 100 in the expanded state.
[0098] The stent delivery system 900 includes a distal tip 900c provided at the distal end 900b. The distal tip 900c features a tapered or atraumatic profile to ensure smooth navigation through the vasculature with minimal trauma.
[0099] The sensor 908 is positioned distal to the balloon 906 and is enclosed within the sensor sheath 910. The sensor 908 is coupled to the catheter shaft 904. The sensor 908 is configured to monitor parameters such as pressure, temperature, or vessel wall contact during stent deployment. The sensor sheath 910 provides mechanical protection and insulation to the sensor 908 while allowing accurate real-time feedback during the procedure.
[00100] An exemplary procedure to deploy the hybrid stent 100 is described below. The procedure is, for example, performed under fluoroscopy. The catheter shaft 904 having the balloon 906 mounted over it, is inserted into a patient’s vasculature (e.g., via a femoral or radial artery) and advanced over a guidewire (not shown) to the target lesion. The medical practitioner manipulates (e.g., push) the handle 902 to control the advancement of the catheter shaft 904. The distal tip 900c is positioned across the target lesion such that the hybrid stent 100 is aligned with the diseased segment. Fig. 9D depicts the balloon 906 in the deflated state and the hybrid stent 100 in the crimped state at the target lesion within a coronary artery 11. The balloon 906 is then inflated via the inflation port 902a, causing radial expansion of the hybrid stent 100 to its intended size and pressing against the vessel wall. The first stent 200 and the second stent 300 deform and lock in place against the vessel wall. Fig. 9E depicts the balloon 906 in the inflated state and the hybrid stent 100 in the expanded state at the target lesion within the coronary artery 11.
[00101] After successful expansion of the hybrid stent 100, the balloon 906 is deflated, and the catheter shaft 904 is withdrawn, leaving the deployed hybrid stent 100 in place as shown in Fig. 2. The balloon 906 and catheter shaft 904 are then retracted proximally, completing the procedure.
[00102] The present disclosure provides a stent interlocking assembly that offers several advantages over conventional stent coupling methods. The interlocking assembly enables precise mechanical engagement between a first stent and a second stent via complementary coupling elements, such as a first coupling element and a second coupling element, forming a passive snap-fit connection. This configuration allows the first and second stents to be pre-coupled ex-vivo, thereby eliminating the need for intraoperative alignment during deployment. The mechanical interlocking provides positional stability along both axial and radial directions, ensuring consistent overlap between the stents and maintaining structural continuity across the inter-stent junction. Additionally, the design permits uniform radial force distribution, reducing localized mechanical stress and minimizing risks of tissue injury or stent malapposition. The interlocking assembly also supports secure crimping and delivery of the hybrid stent as a single unit using standard catheter-based systems, streamlining procedural workflow and reducing deployment time.
[00103] In an embodiment, the interlocking assembly facilitates coupling of a metallic stent and a bioresorbable stent. This configuration combines the high radial strength and long-term durability of the metallic stent with the temporary scaffolding function of the bioresorbable stent. The bioresorbable stent provides mechanical support during the initial post-deployment phase and is gradually resorbed, thereby avoiding long-term presence of foreign material and associated complications such as late thrombosis, chronic inflammation, or restenosis. The metallic stent, which remains in place, maintains long-term patency and structural reinforcement of the vessel.
[00104] 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:WE CLAIM:
1. An interlocking assembly (400) for coupling two stents, the interlocking assembly (400) comprising:
a. a plurality of locking elements (402) for coupling a first stent (200) and a second stent (300), each locking element (402) comprising:
i. a first coupling element (210) comprising: a base (210c) and a protrusion (210d) coupled to the base (210c); and
ii. a second coupling element (310) comprising a groove (310a) configured to engage with the base (210c), thereby coupling the first stent (200) and the second stent (300);
iii. wherein the protrusion (210d) is disposed outside the groove (310a);
wherein at least one first coupling element (210) is provided on the first stent (200), and
wherein at least one second coupling element (310) is provided on the second stent (300).
2. The interlocking assembly (400) as claimed in claim 1, wherein the base (210c) and the protrusion (210d) have a first width (W1) and a second width (W2), respectively, and the groove (310a) has a third width (W3), wherein the first width (W1) is less than or equal to the third width (W3) and the second width (W2) is greater than the third width (W3).
3. The interlocking assembly (400) as claimed in claim 1, wherein the protrusion (210d) of the first coupling element (210) is elastically deformable.
4. The interlocking assembly (400) as claimed in claim 1, wherein the protrusion (210d) comprises an aperture (212).
5. The interlocking assembly (400) as claimed in claim 1, wherein the first coupling element (210) comprises a connecting portion (210e) coupling the base (210c) and the protrusion (210d).
6. The interlocking assembly (400) as claimed in claim 1, wherein a first portion (210c1) of the base (210c) is disposed within the groove (310a) and a second portion (210c2) of the base (210c) is disposed outside the groove (310a).
7. The interlocking assembly (400) as claimed in claim 1, wherein the first stent (200) is made of one or more non-bioresorbable materials and the second stent (300) is made of one or more bioresorbable materials.
8. The interlocking assembly (400) as claimed in claim 1, wherein the first stent (200) is made of one or more bioresorbable materials and the second stent (300) is made of one or more non-bioresorbable materials.
9. A hybrid stent (100) comprising:
a. a first stent (200);
b. a second stent (300); and
c. an interlocking assembly (400) as claimed in any of claims 1 – 6, to lock the first stent (200) and the second stent (300) together.
10. The hybrid stent (100) as claimed in claim 9, wherein the first stent (200) is made of one or more non-bioresorbable materials and the second stent (300) is made of one or more bioresorbable materials.
11. The hybrid stent (100) as claimed in claim 9, wherein the first stent (200) is made of one or more bioresorbable materials and the second stent (300) is made of one or more non-bioresorbable materials.
12. The hybrid stent (100) as claimed in claim 9, wherein the first stent (200) comprises:
a. a plurality of circumferentially extending rows (232) of first struts (230), extending between a proximal end (200a) and a distal end (200b) of the first stent (200), the first struts (230) interconnected to form alternating peaks (230a) and troughs (230b); and
b. a plurality of linkages coupling the plurality of rows (232) in a predefined pattern to form a tubular structure of the first stent (200).
13. The hybrid stent (100) as claimed in claim 12, wherein the plurality of linkages comprises:
a. a plurality of first linkages (217) coupling alternate pairs of adjacently disposed rows (232) such that the first stent (200) comprises a plurality of rows (203) of closed units (201) and a plurality of rows (207) of open units (205) disposed alternatingly between the proximal end (200a) and the distal end (200b), wherein, each first linkage (217) is configured to couple a trough (230b) of a first row (232a) of the pair of adjacently disposed rows (232) with a corresponding peak (230a) of a second row (232b) of the pair of adjacently disposed rows (232) to form one closed unit (201); and
b. a plurality of second linkages (220), each second linkage (220) configured to couple a first closed unit (201a) of a first row (203b) of a pair of adjacently disposed rows (203) of closed units (201) to a second closed unit (201b) of a second row (203c) of the pair of adjacently disposed rows (203) of closed units (201);
wherein each of the at least one first coupling element (210) is provided at an apex (201c) of a corresponding closed unit (201) at the proximal end (200a) or the distal end (200b).
14. The hybrid stent (100) as claimed in claim 13, wherein the first closed unit (201a) and the second closed unit (201b) are circumferentially offset.
15. The hybrid stent (100) as claimed in claim 9, wherein the second stent (300) comprises:
a. a proximal row (303a) of first closed units (301) provided at a proximal end (300a) of the second stent (300);
b. a distal row (303b) of first closed units (301) provided at a distal end (300b) of the second stent (300);
c. a plurality of second rows (307) of second closed units (305) extending coaxially between the proximal row (303a) and the distal row (303b);
d. a plurality of third linkages (320a) coupling at least one first closed unit (301) of one of the proximal rows (303a) or the distal row (303b) with a corresponding second closed unit (305) of an adjacently disposed second row (307); and
e. a plurality of fourth linkages (320b) coupling at least one second closed unit (305) of one second row (307) with a corresponding second closed unit (305) of an adjacently disclosed second row (307);
wherein each of the at least one second coupling element (310) is provided on the third linkages (320a) of the first closed unit (301) of the proximal row (303a) or the distal row (303b).
16. The hybrid stent (100) as claimed in claim 16, wherein the second stent (300) comprises one or more of:
a. a plurality of fifth linkages (320c), each fifth linkage (320c) coupling one pair of adjacently disposed second closed units (305) of one second row (307); or
b. a plurality of sixth linkages (320d), each sixth linkage (320d) coupling one pair of adjacently disposed first closed units (301) of the proximal row (303a) or coupling one pair of adjacently disposed first closed units (301) of the distal row (303b).