WO2023058035A1

WO2023058035A1 - Entrapped rota burr retrieval apparatus

Info

Publication number: WO2023058035A1
Application number: PCT/IN2021/000008
Authority: WO
Inventors: Prashant Ramdas Wankhade
Original assignee: Prashant Ramdas Wankhade
Priority date: 2021-10-08
Filing date: 2021-12-01
Publication date: 2023-04-13

Abstract

An entrapped rota burr retrieval apparatus 23 configured to be inserted over an already installed guidewire in the blood vessel and subsequently advanced over the rota burr drive shaft 26 to the vicinity of the entrapped burr, wherein its cutting head is rotated in order to abrade the calcified atherosclerotic plaque 29 responsible for rota burr entrapment to facilitate its displacement and therein creating the space to retrieve back the entrapped rota burr is disclosed.

Description

ENTRAPPED ROTA BURR RETRIEVAL APPARATUS

TECHNICAL FIELD

[0001] The present invention, in general, relates to interventional techniques used to remove calcified atherosclerotic stenosis inside the blood vessel. Particularly, the invention relates to an apparatus to aid the retrieval of entrapped rota burr stuck in calcified atherosclerotic stenosis inside the blood vessel. More particularly, the present invention relates to an apparatus configured to be inserted over an already installed guide wire in the blood vessel and subsequently advanced over the rota burr drive shaft to the vicinity of the entrapped burr, wherein its cutting head is rotated in order to abrade the calcified atherosclerotic plaque responsible for rota burr entrapment to facilitate its displacement, therein creating the space to retrieve said entrapped rota burr,

BACKGROUND ART

[0002] In the field of interventional cardiology and radiology, various interventions are being performed as 'closed techniques’, i.e., the procedures are being performed with the help of devices that are inserted via peripheral blood vessels through the small tube wherein said devices are then manipulated to perform a specific procedure. Angioplasty is one such procedure. In angioplasty, wherein the vascular stenosis is calcified, then a special system called the rotablation system is used to ablate the hardened calcified atherosclerotic plaques. Entrapped rota burr is one of the complications that may arise in said procedure, wherein the rota burr gets stuck in the calcified atherosclerotic stenosis. Retrieval of said burr is usually done by employing various interventional techniques, and if these techniques fail, then the patient needs to undergo surgical intervention.

[0003] Different apparatuses and methods for cutting or abrading blockages in blood vessels are known in the state-of-the-art literature. For example, US Pat No. 4850957 teaches an atherectomy catheter for removal of occlusive material in an artery. US Pat No. 4020847 details a rotating cutting catheter featuring an elongated blunt-ended hollow tube affixed on the distal end of a flexible catheter. However, this is a motorized apparatus designed to work over the usual guidewire to clear the blockage in the blood vessel. The cutting element of said apparatus consists of cutting blades, wherein the apparatus is designed to mount over the guidewire, and hence can’t be advanced over the wider driver shaft of entrapped rota burr.

[0004] US20030083681 A1 teaches an apparatus for use as a surgical hand piece that features a body, a rotatable shaft extending from the body and including a tissue contacting component such as a burr, and an outer tube connected to the body and surrounding at least a portion of the shaft. However, the cutting element of this apparatus consists of cutting burr. This is primarily a burring apparatus rather than the usual vascular atherectomy catheter that works over the guidewires.

[0005] US Pat No. 4729763 discloses a catheter for removing occlusive material from the stenosis of a blood vessel. But it is a motorized apparatus consisting of a flexible outer tube and a flexible, rotatable inner tube. The cutting element consists of spirally-shaped blade of unequal length disposed circumferentially of the inner tube. These blades have cutting edges that are serrated. However, this apparatus is designed to mount over the guidewire, and hence can’t be advanced over the wider driver shaft of entrapped rota burr. Further, even if said catheter is modified to make it to be able to advance over the rota burr driveshaft, its bulky nature may not allow it to pass through small coronaries that are already narrowed by atherosclerotic and calcified atherosclerotic plaques.

[0006] EP0487590B1 teaches a catheter atherotome (10) and method for its use for performing partial atherectomy in an artery and thereby enlarging the lumen effectively available for blood flow through the artery. The cutting element of this apparatus consists of an expansible cutter head that includes several elongated flexible members mounted in a parallel array and spaced angularly apart from one another about the associated ends of two concentric members. This apparatus is designed to work over the guidewire, and hence it is not possible to advance this apparatus over the rota burr driveshaft. Further, the distal tip of the apparatus doesn’t have cutting properties that can abrade the calcium or atheroma and hence cannot dismantle the calcified atherosclerotic plaque that is responsible for rota burr entrapment. Therefore, it cannot use to retrieve entrapped rota burr.

[0007] From the foregoing, it becomes apparent that there is a need for a simple, low-profile, less-bulky apparatus configured to advance over rota burr shaft and provide a second means to abrade the calcified atherosclerotic stenosis responsible for rota burr entrapment, thereby providing the space for an entrapped rota burr to be removed from the stenosed site.

[0008] The present invention discloses a manually operable entrapped rota burr retrieval apparatus configured to abrade calcified atherosclerotic stenosis inside the blood vessel so as to widen the stenosed lumen to aid the retrieval of an entrapped rota burr in said blood vessel.

SUMMARY OF THE INVENTION

[0009] It is therefore the primary objective of the present invention to propose an entrapped rota burr retrieval apparatus configured to abrade calcified atherosclerotic stenosis inside a blood vessel so as to widen the stenosed lumen to aid the retrieval of an entrapped rota burr in said blood vessel.

[0010] It is another object of the present invention to provide an entrapped rota burr retrieval apparatus that is manually operable.

[0011] It is yet another object of the present invention to propose an entrapped rota burr retrieval apparatus configured to provide a second means to abrade calcified atherosclerotic stenosis in an ongoing interventional cardiology/radiology procedure.

[0012] Accordingly, the present invention provides an entrapped rota burr retrieval apparatus for abrading out calcified atherosclerotic stenosis primarily responsible for rota burr entrapment in the blood vessel. The apparatus comprises of a body tube, cutting head, and hub. The apparatus is advanced over the rota wire and subsequently over the left-over driver shaft of the rota burr after disablement. Cutting head is essentially the cutting element of the apparatus, consisting of a disc of width 1 mm made of nickel-coated brass or similar material, wherein it has a hole in the center for the passage of the rota burr drive shaft. Microscopic (20 to 50 micrometers) diamond chips are embedded on the front surface of said disc, wherein a plurality of draining channels is carved obliquely through the cutting head disc at an angle of 450 to the longitudinal axis of the apparatus. Each set of two adjacent draining channels traverse through the disc from distal to proximal ends in a converging manner, maintaining 450 to the longitudinal axis of the apparatus.

[0013] The body tube is a triple layer structure comprising of outer polyurethane or polyethylene layer, middle flexible steel hose tube or steel braiding, and inner polytetrafluoroethylene layer. Hub has torque plates and a single thread capable of fitting in universal sized 'Y-connector with hemostatic valve and rotating male Luer lock’. The cutting head of the apparatus is configured to abrade the calcified atherosclerotic stenosis inside the blood vessel that is responsible for rota burr entrapment, therein making space for its free retrieval.

BRIEF DESCRIPTION OF DRAWINGS

[0014] FIG.1 shows the entire schema of entrapped rota burr retrieval apparatus.

[0015] FIG.2 illustrates the structure of cutting head.

[0016] FIG.3 depicts the structure of hemostatic valve freezer.

[0017] FIG.4 shows the functioning of hemostatic valve freezer.

[0018] FIG.5 illustrates the rotablation system and its working.

[0019] FIG.6 shows the entrapped rota burr in the calcified atherosclerotic stenosis inside the blood vessel.

[0020] FIG.7 depicts the operational steps of Entrapped rota burr retrieval apparatus

[0021] FIG.8 illustrates various stages involved in the retrieval of entrapped rota burr using entrapped rota burr retrieval apparatus. DESCRIPTION OF EMBODIMENTS

[0022] The preferred embodiments of the present invention will now be explained with reference to the accompanying drawings. It should be understood however that the disclosed embodiments are merely exemplary of the invention, which may be embodied in various forms. The following description and drawings are not to be construed as limiting the invention and numerous specific details are described to provide a thorough understanding of the present invention, as the basis for the claims and as a basis for teaching one skilled in the art how to make and/or use the invention. However, in certain instances, well-known or conventional details are not described in order not to unnecessarily obscure the present invention in detail.

[0023] The preferred embodiment of the present invention teaches an entrapped rota burr retrieval apparatus configured to abrade calcified atherosclerotic stenosis inside the blood vessel so as to widen the stenosed lumen in order to aid the retrieval of an entrapped rota burr in said blood vessel. Said apparatus is adapted to provide a secondary means to abrade the calcified atherosclerotic stenosis inside the blood vessel in order to widen the stenosed lumen in an ongoing interventional procedure, therein creating space for an entrapped rota burr to be removed from the site of vascular stenosis. [0024] Referring to FIG.1, the entrapped rota burr retrieval apparatus comprises of cutting head 1, body tube 2 and the hub 3, wherein the disc shaped cutting head is made of nickel-coated brass or similar material that imparts radiopacity and aids in precisely locating the tip of the apparatus under fluoroscopy. In the preferred embodiment, the disc is 1mm wide, featuring a central hole 7 of diameter 3.7 French (1.22 mm) to facilitate its passage over the already installed rota burr drive shaft. As shown in the figure, the disc is snuggly fitted in the body tube 2 at its distal end. The cutting head 1 is provided with coating of microscopic diamond chips (20- 50 μm) 11 on its front side. As shown in FIG.2, the cutting head further features draining channels 6.

[0025] Referring to FIG.1, the body tube is a triple layer structure comprising of an outer layer 8 made up of polyurethane or polyethylene that imparts properties such as lubrication, decreased thrombogenicity, and su pport/flexibi lity , a middle layer 9 made of a flexible steel hose tube or steel braiding therein making the body kink resistance and impart the property of 1 :1 torque while manipulation, and an inner layer 10 made of polytetrafluoroethylene that makes the lumen smooth and lubricious. Length of the body tube 2 is about 120 cm, which should be longer than the guide catheter through which the apparatus is inserted and subsequently goes beyond the tip of guide catheter. In the preferred embodiment, the internal lumen diameter is 1.5 mm and the thickness of wall is 0.12-0.15 mm. [0026] Referring to FIG.1 , the hub 3 of the entrapped rota burr retrieval apparatus features plurality of torque plates 4 that helps to provide manual rotation of said apparatus. The proximal end has a single thread 5 capable of being fitted to a universal-sized Y-connector featuring hemostatic valve and rotating male Luer lock. Rotating Luer lock helps in torquing the apparatus freely in 360°, whereas the side port of Y-connector helps in sucking or flushing the fluid through the apparatus and the hemostatic valve prevents blood loss. A shows the cross-section of body tube at level ‘a’. B and C depicts the cross section at levels ‘b’ and ‘c’ respectively.

[0027] FIG.2 depicts the structure of cutting head. As shown in the figure, D, the front side of the cutting head, is provided with a coating of microscopic diamond chips 11 of size 20-to 50 μm, which helps in abrading the calcified atherosclerotic plaque that have caused the rota burr to get stuck inside the blood vessel. The cutting head further features a plurality of draining channels 6 and a central hole 7. E illustrates the cross section at level 'a' and F shows the arrangement of adjacent draining channels. Said draining channels 6 are carved obliquely through the cutting head disc at an angle of 45° to the longitudinal axis of the apparatus. Each set of two adjacent draining channels 6 traverse through the disc from its distal to proximal ends in a converging manner, maintaining 45° to the longitudinal axis of the apparatus. This oblique arrangement of draining channels helps to maintain easy backward flow of scrapped material or blood into the body tube. This flow of scrapped material through the obliquely provided draining channels 12 is again augmented by clockwise and counter-clockwise rotation of the apparatus. G shows the 3-dimensional view of the cutting head. H depicts the posterior smooth surface of cutting head and arrangement of adjacent draining channels 6 on the posterior surface.

[0028] FIG.3 shows the structure of hemostatic valve freezer comprising of a conical shaped deformable silicon rubber structure 15 mounted on a thin cylindrical polycarbonate or metallic tube 14 of length 10 mm, wherein the hind end of said hemostatic valve freezer forms the base of the cone. The anterior 3-4 mm of inner surface of metallic tube 14 has a circular-shaped thin inner silicon rubber layer 13 of thickness of 200-400 micron, wherein it works as a seal preventing any blood seepage from the passage between the entrapped rota burr retrieval apparatus and the hemostatic valve freezer. I, J and K illustrates the cross section at the level of ‘inner silicon rubber layer' 13, at level 'b' and at level 'c' respectively. L shows the shape of hemostatic valve freezer, M depicts the longitudinal section through the center of hemostatic valve freezer at level ‘d’ and N shows its 3D structure.

[0029] FIG.4 depicts the functioning of hemostatic valve freezer. Fig 4A shows in situ guide catheter 16 with its hub 17, Y-connector 18, hemostatic valve 19 in Y-connector, and hemostatic valve freezer 20. FIG.4B illustrates the opened up hemostatic valve 21 of Y-connector. FIG.4C shows the advancement of valve freezer through opened up hemostatic valve resulting in the deformation of hemostatic valve freezer 22 resulting in it's fitting within the Y-connector. FIG.4D depicts the advancement of entrapped rota burr retrieval apparatus through the hemostatic valve freezer. Entrapped rota burr retrieval apparatus can smoothly be moved and torqued through said hemostatic valve freezer, which would have been difficult otherwise without the valve freezer as the usual Y-connector fits snuggly over the apparatus, therein preventing its smooth movement for manual rotation.

[0030] FIG.5 illustrates the rotablation system and its working. As shown in the figure, the guide catheter 16 with its hub 17 is engaged to coronary artery 27. Rota wire 31 is passed through guide catheter 16, and through the coronary artery 27 and beyond the calcified atherosclerotic stenosis 30 formed in said artery. Rotablation system consisting of advancer 32, wherein a driver shaft 26 having a Teflon sheath 25 and a rota burr 28 attached to the distal tip of said driver shaft 26 are advanced over the rota wire 31 till the coronary artery 27. Once the rota burr reaches near the calcified atherosclerotic stenosis, the rota burr 28 is rotated at the speed of 1 ,50,000 RPM - 1 ,90,000 RPM with the aid of compressed air, wherein said rotating burr is slowly advanced over the wire through the length of the calcified atherosclerotic stenosis 30. This high-speed revolving burr ablates the hard calcium atherosclerotic plaque 29 in the blood vessel and opens it up. [0031] FIG.6 shows the entrapped rota burr 28 in the calcified atherosclerotic stenosis inside the blood vessel segment 30. Entrapped rota burr is a complication of rotablation procedure wherein during the process, the rota burr gets entrapped in the calcified atherosclerotic stenosis and hence couldn't be pulled back to its original position (i.e., catheter) from where it can be taken back outside the body. Kokeshi Phenomenon can contribute to the burr entrapment wherein the high-speed rotation of the burr could result in transient enlargement of the stenosis by friction heat and hence the burr can easily pass through the calcified atherosclerotic plaques without removing a significant amount of calcification. As the burr is diamond-coated on the front half of its structure alone, it can ablate the calcium stenosis while going forward, but not while returning. The narrow lumen that was transiently dilated during the forward movement of the burr happens to regain its original size once it had moved forward and hence, the burr while returning, might get entrapped in the narrowed lumen.

[0032] FIG.7 depicts the various operational steps of Entrapped rota burr retrieval apparatus. FIG.7A shows rotablation assembly in situ. FIG.7B illustrates the scissors 33 for dissembling rotablation assembly. FIG.7C shows left-over Teflon sheath 25 and drive shaft 26 over the rota wire 31 after the detachment of advancer 32. FIG.7D shows the slitting off Teflon sheath 34 with scissors 33 and FIG.7E depicts the pulling back slit-off Teflon sheath 34 and further slitting off the Teflon sheath till it completely comes out. FIG.7F illustrates the left-over driver shaft 26 over the rota wire 31.

FIG.7G shows the advancement of Entrapped rota burr retrieval apparatus 23 along with hemostatic valve freezer 20 over the rota wire 31 and subsequently over the driver shaft 26. FIG.7H shows the advancement of the hemostatic valve freezer 20 over the body tube 2 of Entrapped rota burr retrieval apparatus 23.

[0033] FIG.7I depicts the opened up hemostatic valve 21 of the Y-connector 18. FIG.7J illustrates the advancement of the hemostatic valve freezer 20 through the opened up hemostatic valve 21 leading to its deformation 22 resulting in it's fitting in Y-connector 18, therein keeping the valve open. FIG.7K shows the advancement of body tube 2 of entrapped rota burr retrieval apparatus 23 through the central hole of deformed hemostatic valve freezer 22. Another universal sized Y-connector 35 is connected to the proximal end of the entrapped rota burr retrieval device. The rotating male Luer lock 36 of said Y-connector 35 aids in torquing the 'entrapped rota burr retrieval apparatus’ 23 freely in 360-degrees. The side port 37 of the Y-connector 35 aids in sucking or flushing the fluid through the apparatus, and the hemostatic valve 38 of Y-connector 35 prevents possible blood loss. FIG.7L shows manual rotation 39 of Entrapped rota burr retrieval apparatus 23. [0034] FIG.8 shows the various stages involved in the retrieval of entrapped rota burr using entrapped rota burr retrieval apparatus 23. FIG.8A depicts the advancement of Entrapped rota burr retrieval apparatus 23 till the calcified atherosclerotic plaque 29 responsible for the entrapment of rota burr. FIG.8B illustrates the ablation of calcified atherosclerotic plaque 29 with the Entrapped rota burr retrieval apparatus 23 by the external manual rotation of apparatus, as shown in FIG.7L. The apparatus is rotated manually in clockwise and counterclockwise directions with gentle forward thrust in order to abrade the calcified atherosclerotic plaque 29. FIG.8C depicts the ablated calcified atherosclerotic plaque creating space 36 for the retrieval of entrapped rota burr 28. FIG.8D illustrates the pulling back of rota burr via space 36 created after ablation of calcified atherosclerotic plaque 29. FIG.8E shows retrieval of rota burr 28 out of calcified atherosclerotic stenosis.

[0035] Although the present invention has been described in connection with the preferred embodiments thereof with reference to the accompanying drawings, it is to be noted that various changes and modifications are possible and are apparent to those skilled in the art. Such changes and modifications are to be understood as included within the scope of the present invention unless they depart there from.

Claims

1. An entrapped rota burr retrieval apparatus, characterized by:

• a disc shaped cutting head 1 made of nickel-coated brass, provided with coating of microscopic diamond chips 11, wherein said disc is snuggly fitted in a body tube 2 at its distal end;

• a hub 3 featuring plurality of torque plates 4 adapted to receive torqueing input, wherein its proximal end features a single thread 5 adapted to be fitted to a universal-sized Y-connector featuring hemostatic valve and rotating male Luer lock; and

• hemostatic valve freezer comprising of a conical shaped deformable silicon rubber structure 15 mounted on a thin cylindrical polycarbonate or metallic tube 14, wherein the hind end of said hemostatic valve freezer forms the base of the cone.

2. The entrapped rota burr retrieval apparatus as claimed in claim 1 , wherein the cutting head features a plurality of draining channels 6 and a central hole 7, wherein said draining channels 6 are carved obliquely through the cutting head disc at an angle of 45° to the longitudinal axis of the apparatus in order to maintain unhindered backward flow of scrapped material or blood into the body tube. The entrapped rota burr retrieval apparatus as claimed in claim 2, wherein each set of two adjacent draining channels 6 traverse through the disc from its distal to proximal ends in a converging manner, maintaining 45° to the longitudinal axis of the apparatus. The entrapped rota burr retrieval apparatus as claimed in claim 2, wherein the flow 12 of scrapped material through the obliquely provided draining channels is augmented by clockwise and counterclockwise rotation of the apparatus. The entrapped rota burr retrieval apparatus as claimed in claim 1 , wherein the body tube 2 comprises of an outer layer 8 made of polyurethane or polyethylene, a middle layer 9 made of flexible steel hose tube or steel braiding to render the body kink resistance and impart the property of 1:1 torque while manipulation, and an inner layer 10 made of polytetrafluoroethylene that makes the lumen smooth and lubricious. The entrapped rota burr retrieval apparatus as claimed in claim 1 , wherein the anterior 3-4 mm of inner surface of metallic tube 14 has a circular-shaped thin inner silicon rubber layer 13 of thickness of 200-400 micron, wherein it works as a seal configured to prevent blood seepage from the passage between said apparatus and the hemostatic valve freezer. The entrapped rota burr retrieval apparatus as claimed in claim 1 , wherein a universal sized Y-connector 35 is connected to the proximal end of the entrapped rota burr retrieval device. A method to retrieve entrapped rota burr, said method characterized by the steps of:

• advancing the entrapped rota burr retrieval apparatus 23 along with hemostatic valve freezer 20 over the rota wire 31 and subsequently over the driver shaft 26, wherein advancing of said hemostatic valve freezer 20 through the opened up hemostatic valve 21 leads to its deformation 22 resulting in it's fitting into the Y- connector, thereby keeping the valve open;

• further advancing the body tube 2 of entrapped rota burr retrieval apparatus 23 through the central hole of hemostatic valve freezer 22;

• further advancing the entrapped rota burr retrieval apparatus 23 till the calcified atherosclerotic plaque 29 responsible for the entrapment of rota burr;

• rotating the male Luer lock 36 to torque the apparatus freely in 360° ; creating space 36 by ablating the calcified atherosclerotic plaque 29 for the retrieval of entrapped rota burr 28; and • pulling out the trapped rota burr through the space 36 created by the ablated calcified atherosclerotic plaque 29. The method as claimed in claim 8, wherein the cutting head is rotated manually in clockwise and counterclockwise directions with gentle forward thrust in order to abrade the calcified atherosclerotic plaque 29. The method as claimed in claim 8, wherein the side port 37 of Y- connector aids in sucking or flushing the fluid through the apparatus.