Pre-loaded inverting tractor thrombectomy apparatuses
Mechanical thrombectomy apparatuses including an inverting, rolling conveyor region (“tractor”) at the distal end that are configured to grab and remove thrombus material. In particular, described herein are mechanical thrombectomy apparatuses that are adapted to prevent premature deployment of the tractor, e.g., by including a tractor hold (e.g., a housing, a lock, a clamp, etc.) or the like to secure the outer end of the tractor against and/or relative to the elongate inversion support.
1. A mechanical thrombectomy apparatus for removing a clot from a vessel, the apparatus comprising:
a catheter having a proximal end and a distal end and a distal end opening;
a tractor comprising a flexible tube that extends within the catheter, inverts over the distal end opening of the catheter and extends over the distal end of the catheter, wherein the tractor is configured to invert by rolling over the distal end opening of the catheter when a first end of the tractor is pulled proximally within the catheter;
a puller coupled to the first end of the tractor, wherein the puller extends within the catheter to the proximal end of the catheter; and
a tractor hold attached to an outer surface of the catheter proximal to the distal end of the catheter, wherein the tractor hold secures a second end of the tractor to an outside surface of the catheter, wherein the tractor is fixed to the catheter until a force greater than a threshold force is applied by pulling the first end of the tractor proximally within the catheter
wherein the threshold force is between 50 g of force and 500 g of force.
2. The apparatus of claim 1 , further comprising a guidewire lumen extending through the catheter, the puller and the tractor, and configured to pass a guidewire.
3. The apparatus of claim 1 , further wherein the tractor hold does not extend to the proximal end of the catheter.
4. The apparatus of claim 1 , wherein the tractor hold extends proximally along the catheter for less than 10 cm.
5. The apparatus of claim 1 , wherein the tractor hold compresses the tractor against the catheter.
6. The apparatus of claim 1 , wherein the tractor hold is configured to hold the second end of the tractor until the threshold force is applied, wherein the threshold force is between 200 g of force and 500 g of force.
7. The apparatus of claim 1 , wherein tractor is biased to expand beyond an outer diameter of the distal end of the catheter in a first relaxed configuration, further wherein the tractor is biased to expand to a second relaxed configuration having an outer diameter that is greater than an inner diameter of the distal end of the catheter, wherein the tractor converts between the first configuration and the second configuration by inverting.
8. The apparatus of claim 1 , wherein a proximal end of the tractor hold is attached to the catheter.
9. The apparatus of claim 1 , wherein the catheter comprises a larger outer diameter region and a smaller outer diameter region that is proximal to the larger outer diameter region, further wherein the tractor hold secures the tractor at one or more of: over the smaller outer diameter region, and between the larger outer diameter region and the smaller outer diameter region.
10. The apparatus of claim 9 , wherein an outer diameter of the tractor hold is flush with the larger outer diameter region.
11. The apparatus of claim 9 , further comprising a stepped transition between the larger outer diameter and the smaller outer diameter.
12. The apparatus of claim 1 , wherein the tractor hold comprises one or more of: a polyether block amide, a polyolefin, a polyethylene, a polypropylene, a polyethylene terephthalate (PET), and a Polytetrafluoroethylene (PTFE).
13. The apparatus of claim 1 , further comprising a tractor lock on the second end of the tractor, wherein the tractor lock engages with the tractor hold to secure the tractor lock on a proximal side of the tractor hold until the threshold force is applied by pulling the first of the tractor proximally within the catheter.
14. The apparatus of claim 13 , wherein the tractor lock comprises a band configured to slide over the outer surface of the catheter.
15. The apparatus of claim 13 , wherein the tractor hold comprises a projection extending from the outer surface of the catheter.