DESC:

Field of Invention
The Present invention relates, generally, to medical devices to occlude a hole, a cavity, an appendage, and particularly, but not exclusively, to occlude a hole or a cavity of a septal defect.

Background
Atrial septal defect is a common congenital heart disease. The human heart is formed of four chambers (left atrium, left ventricle, right atrium, and right ventricle) between which there should be an intact septum. However, sometimes there is an opening in the atrial septum that affects the pressure and blood flow inside the heart and between the chambers. This is called atrial septum defect. The atrial septal defect is mainly formed in the growth and development phase of a foetus. The reason of this anomaly is mainly genes related. Due to the septum defect, the blood flows from left atrium to right atrium. This is not normal and results in pathological changes in right atrium. Due to excess amount of blood, the pressure increases in the right atrium and also enlarges its size. This may cause right atrium hypertrophy, pulmonary hypertension, arrhythmia, heart failure, palpitation, asthma, fatigue, repeated pulmonary infections, and the like. To cure this condition, the septal defect need to be repaired or the leakage causing hole need to be plugged.
Traditionally, the surgery was the only treatment available to plug the septal defect. However, the main shortcomings are open-heart surgery, longer recovery time and high rate of complications.
In recent years, another treatment route, minimally invasive percutaneous procedure, is prominently being practiced. In these procedures, occluder specifically designed for atrial septum defect is delivered to the target site (septal defect) using a delivery cable and deployed to plug the defect. Over a period of time, the endothelial cells develop over the occluder surface and becomes an integral part of the septal anatomy. The delivery cable is introduced through a puncture made in a vessel present on the limbs and the delivery cable is tracked to the atrial septal defect through the vessel network.
However, there are multiple design factors that affect an occluder’s performance and flexibility is one of them. The occluder is deployed in an organ (heart) that continuously moves on its own throughout the life of a human. Hence, the occluder should be adaptable to anatomy of the atrial septal and should be flexible enough to move with the beats of the heart or movement of the atrial septum. Stiff occluder or occluder with non-flexible structure cause stress on the atrial septal and also cause erosion of the tissues with atrial movement. Sometimes, the edges of the occluder cause erosion of the tissue wall due to frictional stress generated at sharp edges of the occluder due to continuous movement of heart mascles (contraction and expansion at each pulse). This may result in device failure in few days to few months. It may cause additional complications as well. Hene, the tissue erosion should be minimal after occluder implantation. Improper structure of an occluder may also create a shunting space that defeats the purpose of implanting an occluder. There should not be any blood leakage from sides or through the occluder. Thrombus formation, embolization are other failure modes that may happen due to improper designing of these devices. The shape and/or anchoring features of occluder should provide adequate radial strength and longitudinal length for atraumatic fixation or anchoring support at the implantation location.
Hence, there is need for an occluder to address above mentioned shortcomings and it is an objective of the present invention to provide a medical device, specifically an occluder, to treat such septal defects by developing a medical device that minimizes erosion, prevents formation of thrombus and provides better conformability at the deployment site.
Brief Description of Drawing
The Detail description is described with reference to the accompanying figures.
FIG. 1 illustrates an isometric view of an occluder, according to an embodiment of present invention;
FIG 2. Illustrates a cross-sectional, side view of an occluder, wherein a first disk and a second disk has concave surface, according to an embodiment of present invention;
FIG 3. Illustrated a cross-sectional, side view of an occluder, wherein a first disk and a second disk has convex surface, according to an embodiment of present invention;
FIG 4. Illustrated a side view of an occluder with a first cap and a second cap, according to an embodiment of present invention;
FIG 5. Illustrated a cross-sectional, front-view of the occluder (100) with indications of DM, DF, DS, LF, LS and Ø1 according to an embodiment of present invention.
Detail Description of the Invention
Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or the like parts. Wherever possible, corresponding, or similar reference numbers will be used throughout the drawings to refer to the same or corresponding parts.
Where the term “comprising” is used in the present description and claims, it does not exclude other elements or steps. Where an indefinite or definite article is used when referring to a singular noun, e.g. “a” “an” or “the”, this includes a plural of that noun unless something otherwise is specifically stated.
The invention is described below in detail with reference to accompanying drawings to make the purposes, technical solutions and advantages of invention understood more clearly with help of the specific embodiment of the invention.
The invention, as per the present disclosure, explains a medical device, specifically an occluder for atrial septal defect, that is percutaneously implantable to close a septal defect, a hole, or a cavity. The occluder comprising a first disk, a second disk, and a middle member. All disks are braided structures that are made by weaving a plurality of wires in a specific pattern. A First ends of these wires are collectively put together in a first cap and a second end of these wires are collectively put together in a second cap. Optionally, these ends of the wires are welded, hooked, clipped, tied, glued to the cap or attached to the cap using any other technique known in the art. In addition, the entire woven structure is hollow braided structure. The density of the wires in different sections of the occluder is different.
The first disk or the second disk is primarily saucer-shaped and at least one face of the first disk and/or the second disk is of either concave or convex shape. The middle member is situated between the first disk and the second disk. The first ends of these wires start from the first cap and form the shape of the first disk, the middle member and the second disk and terminates at the second cap. While transitioning from the first disk to the middle member, the wires form a first waist region of cylindrical shape. Similarly, while transitioning from the middle member to the second disk, the wires form a second waist region of cylindrical shape.
The middle member structure is similar to a torus structure, specifically, similar to a horn torus structure. The peripheral surface of the middle member is similar to a torus shape. However, the top and the bottom sides are similar to a conical shape. The top side of the middle member starts from the first waist region and moves in radial direction (X axis) at an angle till it reaches the peripheral surface of the middle member. Similarly, the bottom side of the middle member starts from the second waist region and moves in radial direction (X axis) at an angle till it reaches the peripheral surface of the middle member. The peripheral surface area of the middle member is slightly bulged out or has a curvature to give it an appearance of outer peripheral surface of a torus shape. Due to this design, the middle member acts as a shock-absorber and gives a cushion-like effect to the occluder if the occluder is compressed from the disk sides. The cushion-like effect increases from centre of the occluder towards the periphery of the occluder. This makes the middle member flexible and helps in adjusting itself into the anatomy of the deployment site to minimize erosion of tissues.
The first waist region and the second waist region are cylindrical in shape and provide a firm and rigid centre part to the occluder. The first waist region has a first length (LF) and the second waist region has a second length (LS). The first length and the second length, together, ensure that the length of the occluder is always at least equal or higher than the summation of the length of the first waist region (LF) and the length of the second waist region (LS) in longitudinal direction (Y-axis).
The first disk has a first diameter (DF), the second disk has a second diameter (DS), and the middle member has a middle diameter (DM). The first diameter (DF) and the second diameter (DS) can be either equal or unequal. However the middle diameter (DM) is smaller than at least one of the first diameter (DF) and the second diameter (DS). In addition, either the first diameter (DF) or the second diameter (DF) will be of highest value among the first diameter, the second diameter and the middle diameter.
Further, the curvature of the peripheral surface of the middle member is defined by a curvature angle (Ø1) that is formed between an imaginary horizontal line on the radial axis (X-axis) that longitudinally divides the middle member in half and a tangent drawn at the centre point of the upper half of the peripheral surface of the curvature..
On deployment of the occluder, the first disk and the second disk keep the occluder affixed at its deployment location and provide complete coverage to the septal defect thus preventing leakage of blood. The middle member provides required thickness to the occluder to fill the gap in tissue wall and it also acts as a shock absorber or a cushion to bear the compressive forces due to heart beats and thus reduces the tissue wall erosion by minimizing friction between the tissue wall and the occluder edges.
The shape of the occluder may vary depending on different values of DM, DF, DS, LF, LS, and Ø1. In addition, the selection of values of DM and Ø1 will affect the shape of the middle member and curvature of the peripheral surface area of the middle member. Accordingly, the shock absorbing or cushioning effect can be customized.

Due to braided structure, any plane or surface of the occluder forms a curved structure at their ends or edges. For clarity purpose, while defining angles, a tangent at the centre of such plane or surface should be drawn and should be extended till it meets the longitudinal axis (Y-axis) or radial axis (X-axis) to form an angle of definite quantifiable value.
As a good practice, the criteria to select the size of the occluder is that the diameter of the occluder should be slightly higher than the effective diameter of the septal defect that need to be occluded. The occluder design should resist the compressive force applied by the tissue walls i.e. the radial strength of the occluder should be higher than the compressive force exerted by the tissue wall of the septal defect that intended to be occluded.
According to an aspect of the present disclosure, the ratio of the middle diameter (DM) to the first diameter (DF) is in range of 1:1 to 1:0.25, specifically in range of 1:1 to 1:0.35 and more specifically in the range of 1:1 to 1:0.5.
According to an aspect of the present disclosure, the ratio of DM to DS is in range of 1:1 to 1:0.25, specifically in range of 1:1 to 1:0.35 and more specifically in the range of 1:1 to 1:0.5.
According to an aspect of the present disclosure, the value of the curvature angle (Ø1) is in the range of 95° to 170°, specifically in the range of 100° to 160° and more specifically in the range of 105° to 150°.
The first cap and the second cap are cylindrical hollow structures and at least one of the first cap and the second cap has provisions for connecting the same to a delivery cable. At least one of them comprises an outer portion and an inner portion. The outer portion has threads on the inner periphery. Optionally, the inner portion and the outer portion are separated with a partition that is situated inside the first cap or the second cap. Further, optionally, the outer portion of at least one cap is closed.
The wires are made of a deformable, biocompatible metal, metal alloy or a polymer. Specifically, the wires are made of a shape memory material that allows to make a structure in different shapes and sizes that deforms on applying a force and returns to their original form once the force is removed. The wires are braided and then given a particular shape, through a known process in the art, to produce an article, here an occluder. After shaping process, in normal state, the occluder will remain in that shape and it can be deformed after applying a force. The occluder will remain in deformed state till the force is applied and it will return to its normal state as soon as the force is removed. This property is utilized in deploying the occluder percutaneously and through endovascular route to the target location.
Further, optionally, the first disk, the second disk and/or the middle member is covered, partially or fully, by a cover. The cover minimizes thrombus formation and/or thrombus leakage. The cover is either sutured or adhered to the occluder. The cover is also beneficial for better endothelization.
According to an embodiment of the present invention, the material of the cover is selected from, but not limited to polymer, cotton, bio-derived, Nano-structured Fabrics, Functionalized Fabrics, Self-healing Fabrics, Smart-sensing Fabrics, Composite Fabrics, Polyurethane, Polypropylene, Polystyrene, Polyethylene, ePTFE, PET, Polyester silk, or a combination thereof. Specifically, the material of the cover is non-woven Polypropylene (spun-bound).
Further, optionally, a plurality of anchors are situated on the outer periphery of the occluder projecting outwardly from the outer contour of the occluder. The location of the anchors is primarily, but not limited to, on the middle member. These anchors are primarily hook shaped, but not limited to the said shape and may include various shape such as V-shaped, straight anchor at an angle etc. The direction of the anchors may also be in same direction, in opposing direction or at an angle with the radial axis (X axis). The anchors are either attached separately to the woven mesh of the occluder or may be a part of the woven mesh. The anchors may also be of equal or unequal lengths.
According to an embodiment of the present invention, the occluder may have additional means for sealing.
According to an embodiment of the present invention, the occluder may have radiopaque markers at suitable points on its peripheral surface.
According to an embodiment of the present invention, the occluder is recapturable and repositionable up to its complete length provided the occluder is not detached from the delivery cable.
According to an embodiment of the present invention, the material of the occluder, including anchor, is selected from, but not limited to, metal, non-metal, alloy, polymer, shape memory alloy, shape memory polymer, bioresorbable material or combinations thereof. Specifically, the material of the occluder is selected from, but not limited to, Stainless steel, Cobalt alloys, pure Iron, Nickel-Titanium alloys, Tantalum, Niobium, Nickel alloys, Magnesium alloys, Zinc alloys, L605, MP25N, Nitinol, Co-Cr, CuZnAl, CuAlNi, polytetrafluoroethylene, polylactide, ethylene-vinyl acetate or combinations thereof. In addition, based on the material selected for the occluder, the delivery mechanism can be a balloon catheter or a catheter for self-expanding devices.
According to an embodiment of the present invention, the material of the fabric cover is selected from, but not limited to polymer, cotton, bio-derived, Nano-structured Fabrics, Functionalized Fabrics, Self-healing Fabrics, Smart-sensing Fabrics, Composite Fabrics, Polyurethane, Polypropylene, Polystyrene, Polyethylene, ePTFE, PET, Polyester silk, or a combination thereof. Specifically, the material of the fabric cover is non-woven Polypropylene (spun-bound).
According to an embodiment of the invention, the occluder, the fabric cover or both are coated, completely or partially, with a coating. The coating composition may be selected from polymeric, metallic, metallic alloy based, non-metallic, clay-based, biological, pharmaceutical, chemical, non-polymeric or combinations thereof. In addition, the coating may contain at least an active agent, an additive to enhance either physical, chemical, or biological performance, a biodegradable polymer, a hydrophilic compound, or combinations thereof.
According to an embodiment of the present invention, the polymer used in the coating is selected from, but not limited to biodegradable polymers, non-biodegradable polymers, polymers of L-lactide, Glycolide or combinations of thereof, poly(hydroxybutyrate), polyorthoesters, poly anhydrides, poly(glycolic acid), poly(glycolide), poly(L-lactic acid), poly(L-lactide), poly(D-lactic acid), poly(D-lactide), poly(caprolactone), poly(trimethylene carbonate), polyester amide, polyesters, polyolefins, polycarbonates, polyoxymethylenes, polyimides, polyethers, and copolymers and combinations thereof.
According to an embodiment of the present invention, the term “active agent” refers to any biologically active compound or a pharmaceutical compound or a drug compound that can be used in a composition that is suitable for administration in mammals including humans. According to one embodiment of the present disclosure, the active agent is anti-cancer drug, antiproliferation drug, anti-restenosis drugs, neurolytic agents, Quaternary ammonium salts, Sodium channel blockers, anesthetics, amino acids, amines, Calcium channel blockers, diuretics, vasovasorum constrictors, neurotransmitter chemicals, venom, sclerosant agents, anti-nerve growth agents, aminosteroids, neurotoxins, antithrombotics, antioxidants, anticoagulants, antiplatelet agents, thrombolytics, anti-inflammatories, antimitotic, antimicrobial, smooth muscle cell inhibitors, antibiotics, fibrinolytic, immunosuppressive, antiangiogenic, antirestenotic, antineoplastic, antimigrative, anti-antigenic agents, or a combination thereof. Examples of the drug include, but are not limited to, everolimus, sirolimus, pimecrolimus, tacrolimus, zotarolimus, biolimus, paclitaxel, rapamycin, and combination thereof. In another embodiment, there can be more than one active agent in the coating to deliver at the target lesion.
According to another embodiment of the present invention, the coating formulation can be coated on the occluder through spray coating, dip coating, chemical vapor deposition, physical vapor deposition, Plasma enhanced chemical vapor deposition, evaporating deposition, sputtering deposition, ion plating, atmospheric pressure plasma deposition, sol-gel method, and 3-D printing.
Primarily, the occluder described herein is used in closing the septal defect in atrial wall. During the deployment, one of the first disk and the second disk is expanded to its normal shape and it is placed on left atrium side septal wall. Another disk is placed on the opposite side i.e. right atrium side septal wall. Wherein, the middle member remains in the hole or the gap. By design, the middle member is more flexible. Concave and/or convex shape of the first disk or the second disk is better for conformability with the anatomy of the septal wall. The occluder having decoupled fist disk, second disk and flexible middle member helps in preventing the stress caused on tissue of the heart and minimizes the erosion. The structure of occluder also helps in preventing formation of thrombosis and prevents embolization as well. to the cover also helps in minimizing the thrombus formation and thrombus leakage.

Given below is an embodiment of the present invention described using accompanying drawings.
Fig 1. Illustrates an isometric view of an occluder (100) that shows a first disk (102), a second disk (104) and a middle member (106). The first end of the plurality of wires (117) are collected and put together in the first cap (110).
Fig 2. Illustrates a cross-sectional, side view of an occluder (100) that shows a first disk (102), a second disk (104) and a middle member (106). the structure starts from the first disk (102) where the first ends of wires (117) are collected and tightly weld in to the first cap (110). The first cap (110) is located at centre of the first disk (102). The woven wires form a saucer-shaped the first disk (102) and move to create the first waist region (118) followed by formation of the middle member (106).
The middle member (106) comprises an upper part (107) and a lower part (108). Both, the upper part (107) and the lower part (108) form a slope initiated from the first waist region (118) and the second waist region (120), respectively, and extend radially till the periphery of the middle member (106). The second disk (104) terminates at the second cap (112). The first disk (102) and the second disk (104) has concave outer surfaces.
Fig. 3 Illustrates a cross-sectional, side view of an occluder (100), wherein the first disk (102) and the second disk (104) have convex outer surfaces.
Fig 4, Illustrates a side view of an occluder (100) with the first cap (110) and the second cap (112).
FIG 5. Illustrates a cross-sectional, front-view of the occluder (100) with indications of locations of the first diameter (DF), the second diameter (DS), the middle diameter (DM), the first length (LF), the second length (LS) and the curvature angle (Ø1).

100 Occluder
102 First disk
104 Second disk
106 Middle member
107 Upper part
108 Lower part
110 First cap
112 Second cap
117 Wires
118 First waist region
120 Second waist region
,CLAIMS:
1. An occluder (100) to occlude a septal defect or a coronary hole, the occluder (100) comprising:
a first disk (102) having a first diameter (DF);
a second disk (104) having a second diameter (DS);
a middle member (106) having a middle diameter (DM);
a first waist region (118) situated between the first disk (102) and the middle member (106); and
a second waist region (120) situated between the second disk (102) and the middle member (106),
wherein the peripheral surface area of the middle member (106) is curved at a curvature angle (Ø1).

2. The occluder (100) as claimed in claim 1, wherein the middle diameter (DM) is either equal or smaller than at least one of the first diameter (DF) and the second diameter (DS).

3. The occluder (100) as claimed in claim 1, wherein the ratio of the middle diameter (DM) to the first diameter (DF) is in range of 1:1 to 1:0.25.

4. The occluder (100) as claimed in claim 1, wherein the ratio of the middle diameter (DM) to the second diameter (DS) is in range of 1:1 to 1:0.25.

5. The occluder (100) as claimed in claim 1, wherein the value of the curvature angle (Ø1) is in the range of 95° to 170°.

6. The occluder (100) as claimed in claim 1, wherein the occluder (100) is made of a braided structure.

7. The occluder (100) as claimed in claim 6, wherein the braided structure is made of a plurality of wires (117) that are woven to form the braided structure.

8. The occluder (100) as claimed in claim 7, wherein the ends of the wires (117) are collected and attached to a first cap (110) and another ends of the wires (117) are collected and attached to a second cap (112).

9. The occluder (100) as claimed in claim 7, wherein the material of the wire (117) is selected from metal, non-metal, alloy, shape memory alloy, shape memory polymer, polymer, biodegradable material, bioresorbable material or combinations thereof.

10. The occluder (100) as claimed in claim 9, wherein the material of the wire (117) is selected from Stainless steel, Cobalt alloys, Iron, Nickel-Titanium alloys, Tantalum, Niobium, Nickel alloys, Magnesium alloys, Zinc alloys, L605, MP25N, Nitinol, CuZnAl, CuAlNi, or combinations thereof.

11. The occluder (100) as claimed in claim 1, wherein the occlude (100) is a hollow structure and, optionally, comprises a cover.

12. The occluder (100) as claimed in claim 11, wherein the cover is selected from a polymer, cotton, bio-derived, Nano-structured Fabrics, Functionalized Fabrics, Self-healing Fabrics, Smart-sensing Fabrics, Composite Fabrics, Polyurethane, Polypropylene, Polystyrene, Polyethylene, ePTFE, PET, Polyester, silk, or a combination thereof.

13. The occluder (100) as claimed in claim 1, wherein the occlude (100) is coated, completely or partially, with a coating.

14. The occluder (100) as claimed in claim 13, wherein the coating is selected from polymeric, metallic, metallic alloy based, non-metallic, clay-based, biological, biodegradable, pharmaceutical, chemical, non-polymeric coatings or combinations thereof.

15. The occluder (100) as claimed in claims 13 or 14, wherein the coating comprises at least one active agent.

16. The occluder (100) as claimed in any of claims 13 to 15, wherein the coating comprises at least one additive to enhance either physical, chemical, therapeutical or biological performance of the coating.

17. The occluder (100) as claimed in claim 14, wherein the polymer used in the coating is selected from biodegradable polymers, nonbiodegradable polymers, polymers of L-lactide, Glycolide, poly(hydroxybutyrate), polyorthoesters, poly anhydrides, poly(glycolic acid), poly(glycolide), poly(L-lactic acid), poly(L-lactide), poly(D-lactic acid), poly(D-lactide), poly(caprolactone), poly(trimethylene carbonate), polyester amide, polyesters, polyolefins, polycarbonates, polyoxymethylenes, polyimides, polyethers or combinations thereof.

18. The occluder (100) as claimed in claim 16, wherein the active agent is selected from anti-cancer drug, antiproliferation drug, antirestenosis drugs, neurolytic agents, Quaternary ammonium salts, Sodium channel blockers, anesthetics, amino acids, amines, Calcium channel blockers, diuretics, vasovasorum constrictors, neurotransmitter chemicals, venom, sclerosant agents, anti-nerve growth agents, aminosteroids, neurotoxins, antithrombotics, antioxidants, anticoagulants, antiplatelet agents, thrombolytics, antiinflammatories, antimitotic, antimicrobial, smooth muscle cell inhibitors, antibiotics, fibrinolytic, immunosuppressive, antiangiogenic, antirestenotic, antineoplastic, antimigrative, anti-antigenic agents, everolimus, sirolimus, pimecrolimus, tacrolimus, zotarolimus, biolimus, paclitaxel, rapamycin or combinations thereof.

19. The occluder (100) as claimed in claim 14, wherein occluder is coated by a method selected from spray coating, dip coating, chemical vapor deposition, physical vapor deposition, Plasma enhanced chemical vapor deposition, evaporating deposition, sputtering deposition, ion plating, atmospheric pressure plasma deposition, sol-gel method, 3-D printing or combinations thereof.

20. The occluder (100) as claimed in claim 1, wherein the occluder is completely recapturable and repositionable.