Claims:1. A medical device (100) comprising:
• a driving means (113) having a shaft, wherein the said driving means (113) includes a brushless DC motor with slotless stator;
• a rotating unit (109) having a proximal end (109a) for breaking and macerating blood clots; and
• a pre-defined coupling means (117) coupled to the driving means, the said pre-defined coupling means (117) includes a holding means (117a) and a securing means (117b), the holding means (117a) being tapered and possesses plural protrusions (10) and (12) at the end for holding respective ends of the shaft (113b) and the rotating unit (109).
2. The medical device (100) as claimed in claim 1 wherein the securing means (117b) includes a number of threads to secure the proximal end (109a) of the rotating unit (109) and the shaft (113b) of the driving means (113).
3. The medical device (100) as claimed in claim 1 wherein the medical device (100) includes:
a first tube (105a) having a reinforced braided tubular structure is mounted over the rotating unit (109).
a second tube (105b) having a tubular structure is attached to the hemostatic valve (107).
4. The medical device (100) as claimed in claim 3 wherein the first tube (105a) includes a reinforced braided tube.
5. The medical device (100) as claimed in claim 3 wherein the distal end (105a’’) of the first tube (105a) is narrower than the proximal end (105a’) of the first tube (105a).
6. The medical device (100) as claimed in claim 5 wherein diameters of the proximal end (105a’) and the distal end (105a’’) are 2.7mm and 1.9mm respectively.
7. The medical device (100) as claimed in claim 3 wherein the proximal end (105a’) includes a hemostatic valve (107).
8. The medical device (100) as claimed in claim 3 wherein the second tube (105b) is made of silicone.
9. The medical device (100) as claimed in claim 8 wherein the distal end (105b’’) of the second tube (105b) holds a three way stop cock (111). , 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:
ROTATIONAL THROMBECTOMY DEVICE

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

3. 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 device, more specifically, the present invention includes a thrombectomy device.
BACKGROUND
[002] Thrombosis is the formation of blood clots (or thrombus) inside a blood vessel thereby obstructing the flow of blood through a circulatory system. Such obstruction may eventually cause various diseases and impair the functioning of the body.
[003] There are different techniques to break and/or dissolve blood clots/thrombus in a human body at various locations. Initially, thrombolytics were injected in a patient’s body for dissolving thrombus which resulted in separate/other complications like drug toxicity and bleeding complications. Further, thrombolytics were found to be effective only for a short period of time and necessitated thrombectomy for macerating blood clots. Moreover, such thrombolytics are costly and require more clinical observation and procedures.
[004] One of the currently existing approaches includes a self-expanding clot retrieval device having a mesh/cavity for capturing the clot and retrieving the same from the patient’s body. Some devices are expanded distally of the thrombus, some are expanded through the thrombus and some are expanded proximally or before the thrombus. The clot is either tangled in the mesh of the device or trapped in the cavity of the device and subsequently retrieved in a catheter. However, the use of such devices have high chances of migration of small clots resulting from breakage of the clot from the mesh which may create further occlusion in the arteries and veins with smaller diameter.
[005] Other approach is mechanical thrombectomy using a device which is mechanically rotated with the help of a mechanical rotating mechanism driven by an external electrical motor. Such devices are mostly in the form of a basket having multiple wires which can be shaped in a vortex form that may be rotated to macerate the thrombus from the blood vessel. However, when such rotating members come in contact with the vessel wall then the endothelial layer of the vessel may be damaged. Further, the chances of puncture of blood vessel are high which may lead to fatal consequences.
SUMMARY
[006] The present invention relates to a medical device for breaking up thrombus or other obstructive material. The device includes a driving means posseing a shaft and a brushless DC motor with a slotless stator. The shaft of the said motor is attached to the proximal end of the rotating unit. The said shaft and rotating unit are coupled together with the help of a pre-defined coupling means.
[007] The structure of the pre-defined coupling means includes a holding means and a securing means. Holding means of the said coupling means being tapered and possesses plurality of protrusions at both the ends of the holding means. Moreover, the structure of the securing means designed to mount over the holding means carrying the shaft and rotating units at it’s two ends respectively. Additionally, two tubes i.e. first and second tubes are secured to the medical device at two separate positions. The said tube exhibit different functionalities during the functioning of the medical device. First tube of the medical device is tapered and a reinforced braided tube which is mounted over the rotating unit.
[008] The other tube i.e. the second tube is attached to the hemostasis valve and is made of silicone. A three way stop cock is also provided at the distal end of the second tube.

BRIEF DESCRIPTION OF THE DRAWINGS
[009] The summary above, as well as the following detailed description of illustrative embodiments, is better understood when read in conjunction with the appended drawings. For the purpose of illustrating the present disclosure, exemplary constructions of the disclosure are shown in the drawings. However, the disclosure is not limited to specific methods and instrumentalities disclosed herein. Moreover, those in the art will understand that the drawings are not to scale.
[0010] FIG. 1 represents a medical device 100 in accordance with an embodiment of the present invention.
[0011] FIG. 2 depicts the tubing 105a in accordance with an embodiment of the present invention.
[0012] FIGs. 2a & 2b represent different embodiments of a slider 107a in accordance with an embodiment of the present invention.
[0013] FIG. 3 illustrates the driving means 113 in accordance with an embodiment of the present invention.
[0014] FIGs. 4a to 4c represent the cone and socket coupling 117 in accordance with an embodiment of the present invention.
[0015] FIG. 5 represents the handle 115 in accordance with an embodiment of the present invention.
DETAILED DESCRIPTION OF THE DRAWINGS
[0016] 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.
[0017] Particular embodiments of the present disclosure are described herein below with reference to the accompanying drawings, however, it is to be understood that the disclosed embodiments are merely examples of the disclosure, which may be embodied in various forms. Well-known functions or constructions are not described in detail to avoid obscuring the present disclosure in unnecessary detail. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a basis for the claims and as a representative basis for teaching one skilled in the art to variously employ the present disclosure in virtually any appropriately detailed structure.
[0018] The term “treatment site” refers to a treatment location where the device is deployed.
[0019] The present invention discloses a medical device which is capable of breaking clots/thrombus and further removing the plaque, clot and/or thrombus from the treatment site for removal or macecaration of blood clots. The treatment site of the present disclosure may include one or more occluded blood vessels including coronary artery, iliac artery, femoral artery, pulmonary artery, etc.
[0020] In an embodiment, the medical device of the present invention is a thrombectomy device. The medical device may include a rotating unit (say, a wire) which is being capable of rotation for breaking as well as removing clots. The medical device is equipped with a rotating mechanism for rotation of the rotating unit. The rotating mechanism includes a brushless, slotless stator and self-integrated driving means powered by a battery. The said driving means is a compact structure with high efficiency. Further, the driving means of the present invention requires minimum power and results in reduced heat dissipation. The driving means further includes a shaft having a provision for attachment of the rotating unit. The rotating unit is attached to the driving means with the help of a pre-defined coupling. The said attachment of the driving means and the rotating unit renders a jerk free and vibration free rotational transmission from the driving means to the rotating unit.
[0021] Now referring specifically to drawings, FIG.1 illustrates the medical device 100. As provided earlier, the medical device 100 may be used for breaking as well as removing the blood clots or thrombus from the treatment site. The treatment site may include, without limitation, one of, a pulmonary artery, a peripheral artery, a dialysis graft or any other artificial graft.
[0022] In an embodiment of the present invention, as depicted in FIG.1, the medical device 100 includes a distal end 101 and a proximal end 103. The medical device 100 further includes various components (as shown in FIG. 1 and described below) which function in a synchronized manner to break and/or remove the blood clots without damaging the endothelial layer of the treatment site. The components include without limitation a first tube 105a, a second tube 105b, a hemostatic valve 107, a rotating unit 109, a three-way stop cock 111, a driving means 113, a handle 115, and a pre-defined coupling means 117.
[0023] The first and second tubes 105a and 105b of the present invention include a tubular structure having a lumen. The said tubes 105a, 105b may be mounted over or attached to the medical device 100 at two different locations in the device thus exhibiting separate functionalities. The first tube 105a may be made of a pre-defined material having significant flexibility such as, without limitation, PEBAX, PTFE (polytetrafluoroethylene), nylon, PET(Polyethylene terephthalate), HDPE (High-density polyethylene), combination of different polymeric material, etc. The first tube 105a may be made by one or more methods such as, extrusion, braiding, coiling, etc, resulting in the formation of extruded, braided or coiled tubing.
[0024] In an embodiment, the first tube 105a is a multi-layered reinforced tubing which is made via braiding as shown in FIG. 2. The said first tube 105a includes three distinct layers with different flexibility transitions. The said three layers may be an outer layer, an intermediate layer and an inner layer (not shown). The outer layer of the first tube 105a may be made up of one or more materilas including nylon, PEBAX, PET(Polyethylene terephthalate), HDPE (High-density polyethylene), etc. In an embodiment, the outer layer of the first tube 105a is made up of PEBAX. The intermediate layer can be developed by braiding or coiling the metal wires like Stainless steel (SS316), nitinol, CoCr, etc. with spherical or rectangular periphery. Further, the use of reinforced braided tube 105a provides kink resistance, high torque-ability and ease in navigation. The inner layer of the first tube 105a is made up of PTFE (polytetrafluoroethylene) which provides lubricity while rotation of the rotating unit 109.
[0025] As shown in FIG. 1, the first tube 105a includes two ends i.e. a proximal end 105a’ and a distal end 105a’’. The distance between the proximal end 105a’ and the distal end 105a’’ defines a length of the first tube 105a. The length of the first tube 105a may range between 600 to 630mm and 1300 to 1330mm. In an embodiment, the length of the first tube 105a is 615mm and 1315mm.
[0026] The first tube 105a may be tapered or non-tapered. In an embodiment, the first tube 105a is tapered and the distal end 105a’’ of the first tube 105a is narrower than the proximal end 105a’ of the first tube 105a. The diameter of the proximal end 105a’ may range from 1.5mm to 3.5mm. The diameter of the distal end 105a’’ may range from 0.5mm to 2.5mm. In an exemplary embodiment, the diameters of proximal end 105a’ and distal end 105a’’ are 2.7mm and 1.9mm respectively.
[0027] Moreover, he proximal end 105a’ of the tube 105a has a higher braid angle compared to the middle and/or distal end 105b’. Such a configuration renders better torque-ability and stiffness to the proximal end 105a’ of the first tube 105a whereas the middle and distal end 105b’ tend to be more flexible.
[0028] In an embodiment, the first tube 105a is made of a flat braided stainless steel wire. The braiding of the wire may be performed via two distinct methods i.e. one wire under another wire or one wire above two wires with different angles at proximal region and distal region. Angle between the braided wires at the proximal region may range from 90° to 120° whereas the angle between the braided wires at the distal region may range from 80° to 100°.
[0029] The first tube 105a as disclosed above may be used for performing the following two functions. The rotating unit 109 may be accommodated in the first tube 105a during insertion of the medical device 100 in a patient’s body. Once the medical device 100 reaches the treatment site, the first tube 105a is retracted to expose the rotating unit 109. Further, to infuse or release a contrast media or a therapeutic agent, a hole (not shown) may also be created at the distal end 105a’’ of the first tube 105a.
[0030] The proximal end 105a’ of the first tube 105a may include a hemostatic valve 107. Additionally, the hemostatic valve 107 is attached to the second tube 105b.
[0031] The second tube 105b is made up of one or more materials including silicone, PTFE (Polytetrafluoroethylene), PET (Polyethylene terephthalate), FEP (Fluorinated ethylene propylene), etc. In an embodiment, the second tube 105b is made of silicone.
[0032] The second tube 105b also includes two ends i.e. proximal end 105b’ and distal end 105b’’. The proximal end 105b’ of the second tube 105b is attached to the hemostatic valve 107. Further, the distal end 105b’’ of the second tube 105b holds a three way stop cock 111 for aspiration of the removed clots. The three way stop cock 111 helps in minimizing the flow of the body fluids inside the medical device 100. The three way stop cock 111 helps in connecting external suction source, saline flush ports, contrast media, etc.
[0033] The slider 107a may be attached on the hemostatic valve 107 for holding and reciprocating movement of the first tube 105a to expose distal end 105a’’ of the rotating unit 109 in order to macerate the thrombus. The slider 107a may have different designs as shown in Figs 2a and 2b. The slider 107a may include a lock mechanism. The lock mechanism restricts the movement of the first tube 105a at the time of rotation of the rotating unit 109. As shown in FIG. 2B, a locking screw 107b is provided on the slider 107a for locking the first tube 105a. It should be noted that other means for example, providing grooving in the handle 115 may also be used for locking.
[0034] The rotating unit 109 of the present invention may be any conventionally known structure used for breaking as well as removing blood clots. The rotating unit 109 may be capable of rotating in such a manner that the clots disposed at the treatment site are broken down into smaller segments.
[001] In an exemplary embodiment as depicted in FIG.1, the rotating unit 109 may be made of a conventional medical grade material known to a person skilled in the art. The rotating unit 109 may be a wire that is made of one or more materials but not limited to stainless steel, nitinol, platinum, tantalum, copper, etc. In an embodiment, the rotating unit 109 is made of nitinol. The rotating unit 109 may include two ends proximal end 109a and the distal end 109b. The length of the rotating unit 109 may correspond to the distance between the proximal end 109a and the distal end 109b of the rotating unit 109. In an embodiment, the length of the rotating unit 109 ranges from 600mm to 1400mm but more preferably 650mm. The diameter of the rotating unit 109 may range from 0.5mm to 1.6mm but more preferably 0.7mm to 1.3mm.
[002] In an exemplary embodiment, the distal end 109b may include a predefined shape. The predefined shape may includes a sine-wave shape, C-shape, etc.
[0035] The rotating unit 109 may be rotated with the help of the driving means 113. In an embodiment, the driving means 113 is a brushless and slotless stator DC motor as shown in FIG. 3. The speed of rotation of the driving means 113 ranges from 5000 to 8000 and more preferably 6500 rpm. In an embodiment, the driving means 113 includes a slotless stator self integrated circuit which provides a compact configuration to the driving means 113. The driving means 113 may include a slotless stator 113a and a shaft 113b. In an embodiment, the diameter of the shaft 113b may range from 1mm to 6mm but more preferably 2.5mm to 3.5mm. In an embodiment, the driving means 113 includes a slotless stator 113a which eliminates vibration and noise caused during rotation of the rotating unit 109. The shaft 113b of the driving means 113 is connected to the rotating unit 109 (as described below).
[0036] Further, the functioning of the medical device 100 requires low power i.e. 9V which may be provided by one or more battery source (not shown).
[0037] The driving means 113 of the present invention minimizes heat dissipation due to negligible friction. Further, the output torque of the driving means 113 is very high compared to the size of the driving means 113. In an embodiment, the efficiency of the driving means 113 is more than 85%. Additionally, as the driving means 113 includes less mechanical components, the reliability and life expectancy of the driving means 113 is enhanced. Owing to the use of the slotless stator 113a, the weight of driving means 113 is quite low i.e. approximately 20gm. Further, as the driving means 113 is slotless and self-integrated, a need for additional drivers to drive the driving means 113 is completely eliminated.
[0038] FIGs. 4A to 4C depict the crossectional view of attachment between the driving means 113 and the proximal end 109a of the rotating unit 109. The said attachment may be a permanent or a temporary link. As a preferred embodiment, the attachment between the driving means 113 and the rotating unit 109 may be made by way of a cone and socket type coupling 117. The coupling 117 is made of one or more materials including aluminium, copper, statinless steel, high speed steel, etc. In an embodiment, the said coupling 117 is made of stainless steel.
[0039] In an embodiment, as depicted in FIGs.4A to 4C, the said coupling 117 includes one or more components like a holding means 117a and a securing means 117b. The holding means 117a has two ends – a first end 117a’ and a second end 117b’ and an intermediate portion 117c’ (helps to hold the coupling in place during the attachment procedure). The holding means 117a possesses one or more protrusions 10 and 12 at both the first and the second ends i.e. 117a’ and 117b’ of the holding means 117a. In an embodiment, the number of protrusions 10 and 12 are three. The said protrusions 10 and 12 of the holding means 117a holds the two respective ends of the shaft 113b and the rotating unit 109.
[0040] The length of the holding means 117a ranges from 2.0mm to 6.5mm. In an embodiment the length of the holding means 117a is 5.0mm.
[0041] Further, the first end 117a’ corresponding to protrusions 10 and the second end 117b’ corresponding to protrusions 12 are narrower at their ends as compared to the central portion of the cone 117c’. The diameter of the first end 117a’ i.e. of protrusions 10 may range from 0.5mm to 1.5mm and the diameter of the second end 117b’ of holding means 117a i.e. the protrusions 12 may range from 1.5mm to 3.5mm. The first end 117a’ holds the proximal end 109a of the rotating unit 109. Whereas, the second end 117b’ holds the end of the shaft 113b.
[0042] Further, a securing means 117b is disclosed. The said securing means 117b may be one or more annular members mounted over the holding means 117a. In an embodiment, three annular members or securing means 117b are disclosed. The said securing means 117b are respectively mounted over the first, second and intermediate portions i.e. 117a’, 117b’, 117c’ of the holding means 117a. The said securing means 117b helps to tightly secure the proximal end 109a of the rotating unit 109 and the shaft 113b of the driving means 113.
[0043] Additionally, the said coupling 117 possesses one or more threads and grooves on the securing means 117b and holding means 117a. In an embodiment, the holding means 117a possesses four adjacently placed compact threads on the surface of both the protrusions i.e. 10 and 12. On the contrary, the securing means 117b possesses four internally placed threads. Moreover, when the securing member is advanced over the holding means 117a, the threaded portions provides or exhibits a secured configuration at both ends of the coupling 117.
[0044] The compression force exerted by the threads and grooves due to the tapered configuration of the holding means 117a helps in tightly holding the shaft 113b of the driving means 113 and the proximal end 109a of the rotating unit 109. The main advantage of the said coupling 117 is that, it can be employed for various dimensioned shafts of the driving means 113 and the rotating units 109. Coupling 117 acts as a cushion that absorbs vibrations and provides jerk-free functioning during the initial as well as further functioning of the medical device 100.
[0045] In an embodiment, the coupling is performed by providing a cotter pin, a flexible coupling (made from silicon, polytetrafluoroethylene, PEBAX, etc.), a threaded arrangement, laser welding, etc.
[0046] The medical device 100 of the present invention may be operated by a user via the handle 115. The handle 115 may be an ergonomically designed structure having a round body as shown in FIG. 5. The ergonomic design helps in better operation and handling of the medical device 100 while using the same at the treatment site. The handle 115 may be provided with a cavity for assembling the above disclosed components of the medical device 100. The handle 115 of the medical device 100 is completely closed.
[0047] The medical device 100 of the present invention is so assembled that all the vibrations are absorbed in the handle 115 and smooth transmission of rotational movement is obtained.
[0048] Examples:
[0049] Example 1 (prior art): A simple sinusoidal shaped wire (thrombectomy wire) was attached to the shaft of the driving means (brushed motor with air gap) with silicone coupling. The device was fed a power of 9V for functioning of the driving means. However, due to an inefficient attachment of wire to the motor shaft and driving means with stator, the vibrations i.e. 0.1 G produced by the driving means during the rotatory motion of the thrombectomy wire were high. Moreover, the size of the handle was also large due to size of the motor. The weight of the motor due to circuit was 120gms. Further, due to improper coupling/attachment of the stainless steel sinusoidal thrombectomy wire, the torque transmitted to the distal end of the wire was less. The SS wire was welded to the motor shaft for motion transfer but due to lack of torque transmission chances of welding failure increased.
[0050] Additionally, an extruded tubing was used to enclose the thrombectomy wire, which had the trackability value of 3.14 N and pushability value of 2.91 N. As exemplified above, the torque transmitted to the thrombectomy wire was quite low. Moreover, the silicone attachment of thrombectomy wire and the motor shaft allowed reduced rotational energy being transferred by the driving member.
[0051] Example 2 (present invention): A sinusoidal shaped nitinol wire was attached to the shaft of the driving means (brushless slotless stator motor) with cone and socket coupling and power of 9V was provided for the functioning of the driving means. With the incorporation of the above mentioned motor and coupling, reduced heat dissipation and less vibrations were produced i.e. 0.05G during the functioning of the medical device. Moreover, the size of the motor was compact and the weight was also reduced i.e. 65 gms as compared to the prior art. Additionally, more torque transmission and jerk free transfer of rotational motion to both the shafts and the thrombectomy wire was observed as compared to the prior art. Further, the use of braided tubing provides 1.86 N tracakbility and 1.18 N pushability with high enhanced flexibility to provide improved navigation inside the tortuous anatomy as compared to the prior art.
[0052] 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.