Claims:WE CLAIM:
1. A method (300) for preparing a pre-looped medical device (100), the method (300) comprising:
a. procuring a suture having a pre-defined length and diameter;
b. forming at least one loop in the suture using an apparatus, the apparatus (200) including a plurality of grooves (201), wherein forming the at least one loop includes wounding the suture within the grooves of the apparatus (200);
c. forming a knot (103) after each loop of the at least one loop (101) to form a looped suture;
d. attaching a pledget (105) adjacent to the knot (103) of the looped suture; and
e. coating the looped suture with a bioactive agent to form a pre-looped medical device (100).
2. The method (300) as claimed in claim 1 wherein the suture is made from nylon, silk or Teflon, polytetrafluoroethylene.
3. The method (300) as claimed in claim 1 wherein the predefined length ranges from 70cm to 110cm
4. The method (300) as claimed in claim 1 wherein the pre-defined diameter ranges from 0.0118inch to 0.0133inch.
5. The method (300) as claimed in claim 1 wherein the apparatus is made from stainless steel, Teflon or Teflon coated stainless steel.
6. The method (300) as claimed in claim 1 wherein the apparatus includes a uniform diameter.
7. The method (300) as claimed in claim 1 wherein the apparatus includes non-uniform diameter.
8. The method (300) as claimed in claim 1 wherein the apparatus includes a plurality of sections detachable from each other with via a locking means 202.
9. The method (300) as claimed in claim 1 wherein the plurality of grooves include grooves being parallel to each other.
10. The method (300) as claimed in claim 1 wherein the plurality of grooves include grooves being angled with respect to each other.
11. The method (300) as claimed in claim 1 wherein the bioactive agent includes sirolimus, everolimus, paclitaxel, tacrolimus, cyclosporine, prednisone or other compounds of the limus group. , 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:
PRE-LOOPED MEDICAL DEVICE AND METHOD OF PREPARATION THEREOF

2. APPLICANT:
Meril Life Sciences Pvt. Ltd., an Indian company of the address Survey No. 135/139 Bilakhia House, Muktanand Marg, Chala, Vapi- 396191, Gujarat, 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 pre-looped medical device. More specifically, the present invention relates to a method for preparing pre-looped medical device.
BACKGROUND
[002] Mitral valve is located between the left atrium and the left ventricle of heart. The mitral valve apparatus includes an anterior leaflet 1, a posterior leaflet 3, chordae tendineae (tendinous cords) 5 and papillary muscles 7 as shown in FIG. 1. The chordae tendineae 5, colloquially known as the heart strings, are tendon-resembling fibrous cords of connective tissue that connect the papillary muscles to the leaflets. The length of the chordae regulates overall chordae tension, mitral hemodynamics and the coaptation area of the mitral leaflets. Further, the chordae tendineae provides a tension to the leaflets for proper functioning of the mitral valve.
[003] However, the chordae tendineae is enlarged, pulled/elongated or ruptured over a period of time because of changes in valve structure due to acquired/congenital causes, mitral valve prolapse, bacterial endocarditis and/or rheumatic heart disease. Due to this, the arrangement of the two leaflets in the valve is disturbed leading to incomplete closure of the valve. It is well reported that even 10% increase in chordae length, doubles the chordal tension. This proves that even minor changes in the length can have significant effects on the tension of the chordae. Elongated or ruptured native chordae are generally responsible for mitral valve prolapse and severe mitral regurgitation.
[004] Mitral valve repair and mitral valve replacement are procedures performed to treat such diseased mitral valves. One of the many techniques used for mitral valve repair is through replacement of the chordae tendineae that support the valve to restore its structural integrity. Replacement of elongated or ruptured chordae with artificial chordae is one of the treatment options available to treat the diseased mitral valve. The replacement may be employed in two different methods, namely, simple suturing of the heart valve cusps and papillary muscles maintaining a length similar to the native chordae or using chordal loops to secure the valve cusps to the papillary muscles.
[005] As per current practice, physician makes chordal loops using sutures during surgery to mimic the function of native chordae tendineae. However, the use of such artificial chordal loops has a limitation of adequate length determination and fixation. In some cases, the suture loops made during the open heart surgery have improper sizes and length thereby, resulting in increased tension on the valve leaflet and papillary muscle causing rupture or improper leaflet movement. Further, improper size and length is associated with complications/failure, residual mitral regurgitation or hemolysis. Also, it is a tedious task for the physician to make chordal loops during an open heart surgery as this process can consume valuable time and extend the procedural time of the surgery multifold. Further, while the physician makes the suture loops, he/she may face difficulties in knotting and handling the suture loops.
[006] Various pre-looped artificial tendineae are also known in the art such as, as disclosed in US Pat. No. US20060287716A1. However, such devices are manufactured using a conventional mandrel. The conventional mandrels are usually flat/cylindrical shaped structures that are used for the formation of loops. The smooth surface of the mandrels results in slipping of a wounded suture at the time of knotting. This slippage may lead to uneven loops or loops with non-uniform lengths. Also, the mandrels include rough/sharp edges that often cause damage to suture surface thereby reducing the tensile strength of the suture.
[007] Therefore, there arises a requirement of pre-looped artificial chordae tendineae which overcomes the aforementioned challenges associated with the conventional artificial chordae tendinae.
SUMMARY
[008] The present invention relates to a method for preparing a pre-looped medical device. The method includes procuring a suture having a pre-defined length and diameter, forming at least one loop in the suture using an apparatus, forming a knot after each loop of the at least one loop to form a looped suture, attaching a pledget adjacent to the knot of the looped suture and coating the looped suture with a bioactive agent to form a pre-looped medical device. The apparatus includes a plurality of grooves. The at least one loop are formed by wounding the suture within the grooves of the apparatus.
[009] 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 DRAWINGS
[0010] 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.
[0011] FIG. 1 shows a native mitral valve.
[0012] FIG. 2 depicts a pre-looped medical device 100 inside a heart in accordance with an embodiment of the present invention.
[0013] FIG. 2a represents a pre-looped medical device 100 in accordance with an embodiment of the present invention.
[0014] FIG. 3 depicts a method 300 to prepare the pre-looped medical device 100 in accordance with an embodiment of the present invention.
[0015] FIGs. 3a, 3b and 3c illustrates different embodiments of an apparatus for making the pre-looped medical device 100 in accordance with an embodiment of the present invention.
[0016] FIGs. 3d and 3e illustrate different embodiment of the apparatus 200 depicted in FIG. 3c in accordance with an embodiment of the present invention.
[0017] FIG. 4 depicts an apparatus ‘A’ of the prior art in accordance with an embodiment of the present invention.
DETAILED DESCRIPTION OF THE DRAWINGS
[0018] 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.
[0019] 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.
[0020] 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.
[0021] 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.
[0022] In accordance with the present disclosure, a pre-looped medical device and a method for preparing the same are disclosed. The pre-looped medical device (or device) is an artificial tendineae that is used to repair or replace a native chordae. The pre-looped medical device of the present invention is used to secure any two biological tissues with each other such as the heart valve cusps and papillary muscles. The device of the present invention are pre-measured and pre-knotted. The device provides an accurate fixation between the heart valve cusps and the papillary muscles. Since, the pre-looped medical device does not require the physician to make loops after getting appropriate dimension of the patient’s chordae during surgery, the pre-looped medical device of the present invention reduces operating time by approximately 10%-30%.
[0023] The device of the present invention is manufactured using a pre-defined method. The method includes looping a suture, coating, etc. The process of looping in the present invention is performed using a pre-defined apparatus. The apparatus includes a plurality of grooves. The dimensions of the grooves correspond to the required length and size of the device. Further, the grooves of the apparatus eliminate the chances of slippage of the suture which in turn prevent the formation of non-uniform loops and/or damage to the suture. Hence, the device formed using the aforesaid method and apparatus have exact dimensions for conformability at a treatment site.
[0024] Fig. 2 illustrates the pre-looped medical device 100 implanted at the treatment site. As shown, the treatment site corresponds to the mitral valve. The pre-looped medical device 100 is attached to a leaflet of a mitral valve 10 at one end while other end of the pre-looped medical device 100 is attached to the papillary muscles 20. The pre-looped medical device 100 includes the exact dimensions for conformability at the treatment site. The pre-looped medical device 100 may have a length ranging from 5mm to 40mm. In an embodiment, the pre-looped medical device 100 includes a length of 25mm.
[0025] The pre-looped medical device 100 may be made of one or more sutures. The suture may be made of a synthetic material including but not limited to nylon, silk, teflon, polytetrafluoroethylene, etc. Alternatively, the suture may be made of a biological material including but not limited to autologous or heterologous pericardium, collagen etc. In an embodiment of the present invention, the suture is made of expanded polytetrafluoroethylene for the replacement of native chordae. Expanded polytetrafluoroethylene (e-PTFE) is used in the present invention as it includes favorable properties like high tensile strength, adequate strength to prevent breakage, no elasticity and no elongation. Further, e-PTFE supports endothelialization and does not cause any tissue irritation. Such properties of e-PTFE are particularly beneficial for chordae replacement since slight change in the length of suture due to elongation may lead to mitral valve failure.
[0026] The suture may include one or more filaments (a multifilament suture or a monofilament suture). In an embodiment, the suture is made of monofilament e-PTFE. The size of the sutures used for replacement of native chordae may range from 6/0 USP to 0/0 USP. In an embodiment, the size of the suture is 4/0 USP. The mean diameter of the suture may range from 0.0118inch to 0.0133inch. In an embodiment, the mean diameter of the suture is 0.0125inch. The knot pull tensile strength of suture ranges from 1.50kg/cm2 to 2.0kg/cm2. In an embodiment, the knot pull tensile strength of the suture is 1.86kg/cm2. The suture may have a length ranging from 70cm to 110cm. In an embodiment, the suture includes a length of 90cm.
[0027] The pre-looped medical device 100 may include at least one loop 101. The loops 101 may be formed by wounding the suture over a pre-defined apparatus (described below in detail). In an embodiment, the number of loops 101 may range from 1 to 10 loops. The number of loops 101 may depend on the type of leaflet prolapsed (anterior leaflet/ posterior) and/or number of diseased tendinous cords. For example, for the treatment of prolapsed anterior leaflet, a set of two loops are required.
[0028] The loops 101 of the present invention may have a length corresponding to the length of the pre-looped medical device 100. In an embodiment, the length of all the loops 101 of the pre-looped medical device 100 is same. In another embodiment, the length of each of the loops 101 of the pre-looped medical device 100 is different.
[0029] The pre-looped medical device 100 includes a knot 103. The knot 103 helps to hold the loops 101 together and to fix the length of the loops 101 of the pre-looped medical device 100. The knot 103 may have a pull tensile strength ranging from 1.5kg/cm2 to 2.0kg/cm2.
[0030] The pre-looped medical device 100 includes a pledget 105 adjacent to the knots 103. The pledget 105 may be made of any soft material know in the art including but not limited to a small wad of lint, dacron fabric, collagen, pericardium tissue etc. The pledget 105 is used to fix the pre-looped medical device 100 with the papillary muscles 20 as shown in FIG. 2. The pledgets 105 of the present invention are structured based upon the shape of the papillary muscles 20 in order to promote easy fixation. The shape of papillary muscles 20 mainly includes conical, broad-apexed, pyramidal, fan shaped, etc. Hence, the shape of pledgets 105 used for fixation in the present invention include conical shaped, broad-apexed, pyramidal or fan shaped.
[0031] The pre-looped medical device 100 may have at least two free ends 107. The number of free ends 107 may be dependent upon the number of sutures used for manufacturing the pre-looped medical device 100. In an embodiment, if a single suture is looped a multiple times then the pre-looped medical device 100 include two free ends 107. The free end 107 may enable the pre-looped medical device 100 to connect with the papillary muscles 20.
[0032] The length of the free ends 107 may range from 60cm to 80cm. The length of all free ends 107 may be same or different. In an embodiment, the pre-looped medical device 100 includes two free ends 107 having a length of 35cm each.
[0033] Each of the free ends 107 may be provided with a needle 109. The needle 109 may be made of any material known in the art. In an embodiment, the needle 109 may be made of stainless steel. The needle 109 helps to fix the free ends 107 with the papillary muscle 20 during the surgery.
[0034] FIG. 3 outlines the method 300 to prepare the above described pre-looped medical device 100. At step 301 of the said method 300, a suture having a pre-defined length and diameter is procured.
[0035] At step 303, the suture may be wounded over an apparatus 200 in order to form loops. The apparatus 200 may be made of a material including but not limited to stainless steel, teflon, teflon coated stainless steel. In an embodiment, the apparatus 200 is made up of stainless steel. The apparatus 200 may resemble a three-dimensional structure known in the art. In an embodiment, the apparatus 200 is a hollow cylinder with a uniform diameter as shown in FIG. 3a and FIG. 3b. The diameter of the apparatus 200 may range from 5mm to 40mm. The diameter of the apparatus 200 may correspond to the length of the pre-looped medical device 100.
[0036] In an alternate embodiment, the apparatus 200 is a non-uniform diameter as shown in FIG. 3c. The apparatus 200 with the non-uniform diameter may be tapered. The non-uniform diameter of the apparatus 200 may enable formation of loops 101 with more than one size. The sizes that can be prepared using the apparatus 200 may be engraved on the corresponding apparatus 200 for easy identification.
[0037] The apparatus 200 may include an outer surface having a plurality of grooves 201. The grooves 201 prevent slipping of the suture from the outer surface of the apparatus 200 while preparing the pre-looped medical device 100.
[0038] The grooves 201 may have a diameter ‘d’ ranging from 0.0039 inch to 0.0196 inch. The grooves 201 may have a diameter ‘d’ corresponding to the diameter of the suture used to prepare the pre-looped medical device 100. The groove 201 may include constant diameter or the diameter of the grooves 201 may vary. The grooves 201 with varying diameter ‘d’ on the apparatus 200 may enable use of sutures having different diameter for preparation of the pre-looped medical device 100.
[0039] The apparatus 200 may have a pre-defined thickness. The thickness of the apparatus 200 may range between 0.5mm to 5mm. The thickness of the apparatus 200 may render the apparatus 200 flexible. The flexibility of the apparatus 200 may help dislodge the pre-looped medical device 100 from the grooves 201 when a user may flex the apparatus 200 with an inward force thereby reducing a strain given by the apparatus 200 to the pre-looped medical device 100.
[0040] The grooves 201 may either be parallel to each other (FIG. 3a) or may be angled with respect to each other (FIG. 3b & 3c). The grooves 201 may be angled with respect to each other with an angle ranging from 10° to 35°, preferably from 15° to 30°. The grooves 201 may gather together at a point (FIG. 3c).
[0041] The apparatus 200 may be in the form of an integral structure having grooves 201 disposed in different sets as shown in FIGs. 3a-3c. Alternately, the apparatus 200 may include a plurality of detachable sections 200a-200c as shown in FIGs. 3d and 3e. Each section 200a-200c may be provided with a pre-defined set of grooves 201.
[0042] Each section 200a-200c may include same or different dimensions. Each of the sections 200a-200c may include a tapered shape having progressively increasing dimensions from the section 200a to the section 200c to from a tapered apparatus. The tapered apparatus 200 with detachable sections helps in generating loops of the device 100 according to the native chordae in a single procedure as per the requirement during surgery.
[0043] The attachment as well as detachment of the sections 200a, 200b, 200c with each other may be mediated via a plurality of locking means 202. In an embodiment, the locking means 202 is a thread lock (shown in FIG. 3d). In an alternate embodiment, the locking means 202 is a push lock (shown in FIG. 3e). The pre-looped medical device 100 may be easily slid off from the grooves 201 of the sections 200a-200c.
[0044] The suture may be wounded over the apparatus 200 as described above for one or more times based on the desired number of loops 101 required to be formed.
[0045] At step 305, the knot 103 may be tied after every loop 101 is wounded over the apparatus 200. Alternatively, the knot 103 may be tied after a desired number of loops 101 are obtained.
[0046] At step 307, the suture wounded over the apparatus 200 may be left undisturbed for a period of time ranging from 0.5 hour to 6 hour for shape setting of the wounded suture.
[0047] At step 309, the top section of the apparatus 200 may be detached leaving the suture wounded over the base section. The wounded suture may be removed from the base section by sliding it off to obtain the pre-looped medical device 100.
[0048] At step 311, the free ends 107 of the pre-looped medical device 100 may be attached with the needles 109. The attachment between the free ends 107 and the needles 109 may be made by way of a temporary or a permanent provision. For example, the free ends 107 and the needles 109 may be glued with each other.
[0049] At step 313, the knots 103 of the loops 101 may be attached adjacent to the pledget 105. The attachment between the knots 103 and the pledget 105 may be made by way of a temporary or a permanent provision. For example, the knots 103 and the pledget 105 may be glued with each other.
[0050] At step 315, the pre-looped medical device 100 obtained is coated with a bioactive agent. The bioactive agents may include but are not limited to anti-proliferative agents and anti-inflammatory agents. Exemplary drugs of bioactive agent include but are not limited to sirolimus, everolimus, paclitaxel, tacrolimus, cyclosporine, prednisone or other compounds of the limus group and likewise. In an embodiment, a coating with the anti-proliferative drug namely, sirolimus. The bioactive agent may be coated by any method known in the art.
[0051] The bioactive agent may be combined with a polymer for coating on the suture of the pre-looped medical device 100. The polymer may include a non-biodegradable polymer or a biodegradable polymer, preferably a biodegradable polymer. The biodegradable polymer may include but are not limited to poly-dl-lactide, poly-DL-lactide-co-glycolide, poly-L-lactide, poly-L-lactide-co-caprolactone, polycaprolactone, etc. The polymer helps in regulating the release kinetics of the coated bioactive agent at the treatment site.
[0052] The coating may be provided either before or after preparation of the pre-looped medical device 100. In an embodiment, the coating is provided after the pre-looped medical device 100 is prepared. Coating after the pre-looped medical device 100 is prepared prevents possible drug loss due to handling of the sutures.
[0053] Thereafter, the pre-looped medical device 100 may be ready for use at the treatment site.
[0054] The present invention may be supported by the following examples:
[0055] Example 1: A monofilament ePTFE suture (USP4/0) was used to create artificial chordae loops. The loop formation was carried out using a predefined apparatus ‘A’ (as shown in FIG. 4) during the surgery after measuring the native chordae. A suture was applied over the apparatus ‘A’ to create a desired number of loops. Once the loops were formed, they were verified and further a knot was provided to secure the length of the loops.
[0056] It was observed that the above process alone took around 30min-60min during surgery. Further, variation in sizes of the loops from the measured chordae length was found. Further, increased tension on the valve leaflet and papillary muscle was observed resulting in rupture/improper leaflet movement.
[0057] Example 2: A monofilament ePTFE suture was used to create pre-looped medical device. The apparatus of the present invention was used to create the pre-looped sutures. The apparatus included a hollow cylinder with uniform diameter. A plurality of grooves was disposed on the outer surface of the apparatus.
[0058] Owing to the readily available pre-looped medical device, the chordal replacement procedure was simplified. It was observed that the risk of complication arising due to improper sizes was minimized. Also, due to the pre-looped suture of the present invention, surgery time that was reduced to 30min-40min.
[0059] 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.