EP-4736789-A2 - HYBRID ATHERECTOMY DEVICES

EP4736789A2EP 4736789 A2EP4736789 A2EP 4736789A2EP-4736789-A2

Abstract

Telescoping, self-driving, and laterally-pushing atherectomy devices are provided, each having a flexible sheath, a cutter with helical flutes, and a drive assembly. The drive assembly can have a flexible driveshaft rotatably translational with the lumen of the flexible sheath, a positive displacement pump to transport cut tissue, and a flexible drive shaft that can be longer than the flexible sheath for a reversible telescoping of the drive assembly from the lumen of the flexible sheath. The positive displacement pump can be a screw pump having a drive screw portion exposed for contact with a vascular lumen for a self-driving of the device through the vascular lumen. A reversibly-expandable, lateral pushing member can be included at the distal end of the flexible sheath for a lateral pushing of the cutter. Improved cutting heads, and methods of making them, are provided for cutting a combination of soft and hard plaque.

Inventors

TO, JOHN
ESCUDERO, PAUL

Assignees

Avantec Vascular Corporation

Dates

Publication Date: 20260506
Application Date: 20220607

Claims (15)

An atherectomy device, comprising: a distal end, a proximal end, a long axis, and a guidewire lumen passing through the device in the direction of the long axis; a flexible sheath having an outer diameter and a sheath lumen; a cutter having a proximal end, a distal end, and a body with a plurality of helical flutes that include a first helical flute 931 and a second helical flute 932, each of the flutes having a respective helix angle and forming a respective helical channel that is open at the distal end of the cutter and the proximal end of the cutter; a plurality of primary cutting edges that include a first primary cutting edge 905-1 and a second primary cutting edge 905-2; a plurality of secondary cutting edges that include a first secondary cutting edge 910-1, a second secondary cutting edge 910-2; a plurality of secondary facets 973 including a first plurality of secondary facets 972, and a second plurality of secondary facets 974; wherein, the first plurality of secondary facets 972 form the first secondary cutting edge 910-1 following the first primary cutting edge 905-1; and, the second plurality of secondary facets 974 form the second secondary cutting edge 910-2 following the secondary primary cutting edge 905-2; a cutter lumen; and a cleared diameter. and, a drive assembly having a flexible driveshaft including an axis, a proximal end, a distal end, an outer surface, and a driveshaft lumen, the distal end of the flexible drive shaft having a fixed connection with the cutter, wherein the flexible drive shaft is rotatably translational with the lumen of the flexible sheath; a drive screw attached to the outer surface of the drive shaft and adjacent to the helical flutes at the proximal end of the cutter, the drive screw extending beyond the flexible sheath and exposed for contact with a vascular lumen during use of the atherectomy device within the vascular lumen; and, is either a right hand screw when the cutter is rotated in the right-hand direction; or, a left hand screw when the cutter is rotated in the left-hand direction. wherein, the guidewire lumen includes the cutter lumen and the driveshaft lumen.
The atherectomy device of claim 1, wherein the cleared diameter of the cutter is greater than the outer diameter of the flexible sheath.
The atherectomy device of claim 1, wherein the flexible drive shaft is longer than the flexible sheath to enable a reversible telescoping of the drive assembly from the lumen of the flexible sheath at the distal end of the flexible sheath.
The atherectomy device of claim 1, wherein the cutter further includes; a third primary cutting edge 905-3 extending helically from the distal end to the proximal end of the cutter and along the radius; a third helical flute having a helix angle and forming a helical channel that is open at the distal end and the proximal end of the cutter; a third plurality of secondary facets 976 that form a third secondary cutting edge 910-3 at the distal end of the third helical flute; and, configurations that extend the distal reach of the cutting edges, including a plurality of first primary facets 971 at the distal end of the first primary cutting edge 905-1 configured to extend the reach of the first primary cutting edge 905-1; a plurality of second primary facets 973 at the distal end of the second primary cutting edge 905-2 configured to extend the reach of the second primary cutting edge 905-2; and a plurality of third primary facets 975 at the distal end of the third primary cutting edge 905-3 configured to extend the reach of the third primary cutting edge 905-3.
The atherectomy device of claim 1 , further comprising a reversibly-expandable, lateral pushing member at the distal end of the flexible sheath.
The atherectomy device of claim 1, further comprising a reversibly-expandable, lateral pushing member at the distal end of the flexible sheath; the lateral pushing member having a proximal end, a distal end, a collapsed state, and an expanded state, the proximal end having an operable connection with the flexible sheath, and the distal end having an operable connection with the cutter; wherein, the operable connection with the flexible sheath and the operable connection with the cutter are each configured to receive an axial force (i) applied along the axis of the flexible drive shaft from the cutter to the flexible sheath and (ii) transferred through the lateral pushing member during the collapse and the expansion of the lateral pushing member with the reversible telescoping of the flexible drive shaft from the flexible sheath; and, the operable connection with the cutter is configured as a rotatably translatable connection to facilitate the rotation of the cutter and the flexible drive shaft without rotating the lateral pushing member during operation of the atherectomy device.
The atherectomy device of claim 3, further comprising a reversibly-expandable, lateral pushing member at the distal end of the flexible sheath.
The atherectomy device of claim 3, the lateral pushing member having a proximal end, a distal end, a collapsed state, and an expanded state, the proximal end having an operable connection with the flexible sheath, and the distal end having an operable connection with the cutter; wherein, the operable connection with the flexible sheath and the operable connection with the cutter are each configured to receive an axial force (i) applied along the axis of the flexible drive shaft from the cutter to the flexible sheath and (ii) transferred through the lateral pushing member during the collapse and the expansion of the lateral pushing member with the reversible telescoping of the flexible drive shaft from the flexible sheath; and, the operable connection with the cutter is configured as a rotatably translatable connection to facilitate the rotation of the cutter and the flexible drive shaft without rotating the lateral pushing member during operation of the atherectomy device.
A system comprising the atherectomy device of claim 1 and a guidewire.
A system comprising the atherectomy device of claim 3 and a guidewire.
The atherectomy device of claim 1, further comprising a compressible sleeve to increase the torsional stiffness of the lateral pushing member.
The atherectomy device of claim 1, the first primary cutting edge and the second primary cutting edge extending helically from the distal end to the proximal end of the cutter; wherein, the cutter has a lumen configured for passage of a guidewire; and, effectively cuts both soft and hard plaque in blood vessels.
The atherectomy device of claim 4 the first primary cutting edge, the second primary cutting edge, and the third primary cutting edge extending helically from the distal end to the proximal end of the cutter; wherein, the cutter has a lumen configured for passage of a guidewire; and, effectively cuts both soft and hard plaque in blood vessels.
The atherectomy device of claim 4, further comprising a reversibly-expandable, lateral pushing member at the distal end of the flexible sheath; wherein, the first primary cutting edge, the second primary cutting edge, and the third primary cutting edge extending helically from the distal end to the proximal end of the cutter; wherein, the cutter has a lumen configured for passage of a guidewire; and, effectively cuts both soft and hard plaque in blood vessels.
The atherectomy device of claim 14, further comprising a fourth primary cutting edge extending helically from the distal end to the proximal end of the cutter; and, a fourth helical flute having a helix angle and forming a helical channel that is open at the distal end of the cutter and the proximal end of the cutter.

Description

CROSS REFERENCES TO RELATED APPLICATIONS This application claims priority to U.S. Application No. 17/833,967, filed June 7, 2022, which claims the benefit of U.S. Provisional Application No. 63/197,970, filed June 7, 2021, each of which is hereby incorporated herein by reference in its entirety. BACKGROUND Field of the Invention The teachings herein are directed generally to medical devices and methods, including devices and methods for performing atherectomies through both soft and hard vascular plaque. Description of the Related Art An atherectomy is a minimally invasive procedure for removing atherosclerosis from blood vessels within the body and is an alternative to angioplasty in the treatment of narrowing arteries. Common applications include peripheral arterial disease and coronary artery disease. Unlike angioplasty and stents, which push plaque into the vessel wall, the atherectomy procedure cuts plaque away from the wall of a blood vessel. While atherectomies are usually used to remove plaque from arteries, they can also be used in veins and vascular bypass grafts, for example. Atherectomies can offer improvements over balloon dilatation and stent placement, which are considered traditional interventional surgical methods of treating atherosclerosis. In balloon dilatation, a collapsed balloon is inserted into a blood vessel and inflated to push plaque against the vessel wall, and the stent can be placed to hold the plaque as a scaffolding in order to try and maintain the integrity of the lumen of the vessel. However, such traditional treatments can stretch the artery and induce scar tissue formation, while the placement of a stent may also cut arterial tissue and induce scar tissue formation. The scar tissue formation can lead to restenosis of the artery. Moreover, the dilatation with the balloon can also rip the vessel wall. Because atherectomies enlarge the lumen by removing plaque rather than stretching the vessel, risk of suffering vessel injuries, such as dissections that can lead to increased restenosis, is reduced. Unfortunately, the art suffers performance limitations in state-of-the-art atherectomy devices. For example, current devices with rotating cutters cannot handle the variety of soft, fibrous and calcific plaque effectively, either not cutting all types of plaque or breaking up the plaque into large pieces that remain in the arterial bed as emboli that can clog blood vessels downstream. As plaque is a tissue made of fat, cholesterol, calcium, fibrous connective tissue and other substances found in the body, it can be highly variable and classified mainly into four different types of tissue: calcified and hard, necrotic and soft, fibrotic, and a combination thereof. Calcified plaque can be hard as a bone; fatty plaque is typically soft; and fibrotic plaque is typically viscoelastic, stretchy yet firm, and thus difficult to cut. Some state-of-the-art devices have burrs that can grind-away hard plaque but can't cut soft or viscoelastic plaque. Worse yet, they can loosen debris that can become dangerous emboli. Some state-of-the-art devices have a sharp cutter that can be deflected against one side of the vessel to do eccentric cutting, which is desirable, but the amount of deflection can't be effectively controlled. And, some state-of-the-art devices have a "nose cone" that prevents the cutter from cutting through lesion that doesn't allow enough progression of the device to reach the cutter blades. Most importantly, however, is that patients having "tight" or "tough" lesions are currently unable to receive treatments with balloons, stents, or atherectomy devices. Such lesions are occlusions that leave only a very small luminal opening, or no opening, making it difficult-to-impossible to achieve passage of a guidewire, much less passage of a balloon or stent on the guidewire. For example, a luminal opening that is only 0.5 mm may allow passage of a guidewire, perhaps, but the smallest stents may be 1.0 mm, and the smallest balloon may be 0.75 mm, neither of which can pass through a tough, small lesion for the treatment. And, as noted above, current atherectomy devices have a difficult time cutting away the plaque, even if the guidewire might be able to pass through the luminal opening. In situations having a total occlusion, the problem is exacerbated. As such, one of skill will appreciate an atherectomy device that (i) can effectively cut and remove the 4 different types of plaque tissue, namely calcified and hard, necrotic and soft, fibrotic, and a combination thereof; (ii) can render a concentric vessel lumen with minimal plaque burden; (iii) can safely self-collect and remove plaque particles to avoid release of emboli; and, (iv) can effectively treat a blood vessel with a reduced risk of suffering vessel injuries that can lead to increased restenosis. In addition, the skilled artisan will certainly appreciate having an atherectomy device that (v) can handle these tight or tough le