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EP-4427686-B1 - EXPANDABLE MOUTH CATHETER

EP4427686B1EP 4427686 B1EP4427686 B1EP 4427686B1EP-4427686-B1

Inventors

  • KEATING, KARL
  • KELLY, Ronald J.

Dates

Publication Date
20260513
Application Date
20200910

Claims (13)

  1. A catheter system actuatable to a deployed state, comprising: a catheter body (250) comprising a lumen (257); and a dilator (270) positioned at least partially within the lumen, a distal end (278) of the dilator releasably connected to a distal tip (251) of the catheter body, the dilator being retractable to expand and invert the distal tip such that the distal tip forms a funnel shape in the deployed state, the distal tip comprising: a proximal segment (255); and a distal segment (252) extended from the proximal segment and being substantially flexible, a proximal end (253) of the distal segment extended from the proximal segment and comprising a pull ring (254) adjacent and/or connected to a distal end (258) of the distal segment, and the dilator comprising: a proximal segment (276); a distal segment (277) distal of the proximal segment of the dilator comprising a greatest diameter greater than the proximal segment of the dilator, the distal segment of the dilator comprising: a distal contact element (271) extended radially outward from the distal segment of the dilator and configured to contact and translate proximally the pull ring until being aligned at or adj acent the proximal end of the distal segment of the distal tip of the catheter body; and a proximal contact element (273) proximally spaced from the distal contact element and extended radially outward from the distal segment of the dilator and configured to contact and translate proximally the pull ring, wherein the pull ring is connected between the distal contact element and the proximal contact element.
  2. The system of claim 1, a midpoint of the distal segment of the distal tip in a collapsed state transitions to being a distalmost atraumatic end of the funnel shape in the deployed state distal of the catheter body.
  3. The system of claim 1, the distal segment of the distal tip in a collapsed state being substantially tubular and in the deployed state comprising the funnel shape, an air cushion formed by the funnel shape between the distal end and the pull ring.
  4. The system of claim 1, the distal segment of the distal tip divided into a proximal braid portion and a distal spiral portion.
  5. The system of claim 1, the proximal contact element comprising a diameter less than the distal contact element.
  6. The system of claim 1, the distal contact element comprising an interference fit with the distal end of the distal tip of the catheter body.
  7. The system of claim 1, the distal segment of the dilator comprising a greatest diameter at the distal contact element and decreases from the distal contact element to a distal end of the distal segment of the dilator.
  8. The system of claim 1, the distal segment of the dilator comprising a greatest diameter at the distal contact element and tapers from the distal contact element to a junction between the proximal segment of the dilator and the distal segment of the dilator.
  9. The system of claim 1, the proximal segment of the dilator being highly flexible or substantially more flexible than the distal segment of the dilator, optionally the system further comprising: a substantially flexible segment extending distally of the distal segment of the dilator, the substantially flexible segment being a short nose.
  10. The system of claim 1, the proximal segment of the dilator comprising a fiber reinforcement system to negate elongation.
  11. The system of claim 1, wherein the proximal end of the distal tip and the pull ring are locked together in the deployed state.
  12. The system of claim 1, the distal tip being configured to first expand to a substantially conical shape before inverting to form the funnel shape.
  13. The system of claim 1, the distal tip comprising a braid comprising proximal, middle and distal portions, wherein the braid comprises filaments extended from proximal to distal portions in a helical configuration, wherein the distal portion comprises sufficient radial force to push the proximal portion radially outwardly while being configured to accommodate various vessel sizes in an atraumatic manner.

Description

Field The present disclosure generally relates to devices and methods for removing acute blockages from blood vessels during intravascular medical treatments. More specifically, the present disclosure relates to an expandable catheter used in aspiration of clots. Background Clot retrieval catheters and devices are used in mechanical thrombectomy for endovascular intervention, often in cases where patients are suffering from conditions such as acute ischemic stroke (AIS), myocardial infarction (MI), and pulmonary embolism (PE). Accessing remote areas such as the neurovascular bed is challenging with conventional technology, as the target vessels are small in diameter, distant relative to the site of insertion, and are highly tortuous. The clot itself can complicate procedures by taking on a number of complex morphologies and consistencies, ranging from simple tube-shaped structures which assume the shape of the vessel to long, strand-like arrangements that can span multiple vessels at one time. The age of a clot can also affect its compliance, with older clots tending to be less compressible than fresh clots. Fibrin rich clots also present a challenge in having a sticky nature that can cause a clot to roll along the outer surface of a mechanical thrombectomy device rather than being gripped effectively. Combinations of soft and firm clot regions can also separate during aspiration, with fragmentation leading to distal embolization which can occur in vessels that cannot be reached with currently available devices. Additionally, breaking the bonds adhering the clot to the vessel wall without damaging fragile vessels is a significant challenge. Conventional clot retrieval catheters, especially those for operating in the neurovascular, can suffer from a number of drawbacks. First, the diameters of the catheters themselves must be small enough to avoid causing significant discomfort to the patient. The catheter must also be sufficiently flexible to navigate the vasculature and endure high strains, while also having the axial stiffness to offer smooth advancement along the route. Once at the target site, typical objects to be retrieved from the body can be substantially larger in size than the catheter tip, making it more difficult to retrieve objects into the tip. For example, fibrin-rich clots can often be difficult to extract as they can become lodged in the tip of traditional fixed-mouth catheters. This lodging can cause softer portions of the clot to shear away from the firmer regions, leading to distal embolization. Small diameters and fixed tip sizes can also be less efficient at directing the aspiration necessary to remove blood and thrombus material during the procedure. The aspiration suction must be strong enough such that any fragmentation occurring through the use of a mechanical thrombectomy device or other methods can, at the very least, be held stationary so that fragments cannot migrate and occlude distal vessels. When aspirating with a traditional fixed-mouth catheter, however, a significant portion of the aspiration flow ends up coming from vessel fluid proximal to the tip of the catheter where there is no clot. This significantly reduces aspiration efficiency, lowering the success rate of clot removal. The disclosed design is aimed at providing an improved aspirating retrieval catheter which addresses the above-stated deficiencies. US2001011182A1 describes a device for the removal of a blockage in a passageway such as a dialysis graft or in a body passageway includes a catheter for reception and aspiration of the blockage and an occlusion engaging element distal of the distal end of the catheter which occlusion engaging element is supported on a wire that extends through the catheter. At the distal end of the catheter, there is a device such as a multi-wing malecot expansion device that is expanded after the catheter is placed in position so as to block the occlusion from passing around the outside of the catheter. The support wire can be a movable core guide wire which has a braided device on its distal end. When the core is as distal as possible of the distal end of the shell, the braid is in a collapsed minimum diameter state for insertion through the catheter and through the occlusion. Proximal movement of the core causes the braid to expand to the wall of the graft. Subsequent proximal movement of the entire support wire causes the braid to contact the occlusion forcing the occlusion into the catheter for aspiration and removal. US5971938A describes an access device has a distal, expandable member with a low-profile state facilitating insertion and a high-profile state facilitating operation of the device. An obturator can be used to move the expandable member between its two states. Alternatively, the device can have an outer tube and an inner tube connected to respective ends of a cylindrical expansion member, so that co-axial movement of the tubes changes the state of the member. An act