Device and method for bridging a neck of an aneurysm

Abstract

A system for removing a thrombus. The system includes an expandable device that maintains axially fixed engagement with the thrombus. The expandable device applies a first force to the thrombus according to surrounding vessel size. The expandable device applies a second force to the thrombus according to an increased vessel size to maintain axially fixed engagement.

Description

RELATED APPLICATIONS[0001]This application is a continuation of U.S. patent application Ser. No. 14 / 372,778 filed Jul. 17, 2014, which is a National Phase of PCT Patent Application No. PCT / US2013 / 021942 having International filing date of Jan. 17, 2013, which claims the benefit of priority of U.S. Provisional Patent Application Nos. 61 / 693,026 filed Aug. 24, 2012, 61 / 679,508 filed Aug. 3, 2012 and 61 / 587,617 filed Jan. 17, 2012. The contents of the above applications are all incorporated by reference as if fully set forth herein in their entirety.FIELD AND BACKGROUND OF THE INVENTION[0002]Stroke is a leading cause of disability, death and health care expenditure. Most strokes are ischemic (i.e. caused by a decrease in the blood supply to a portion of the brain due to a clot obstructing the flow of blood). A total or hemodynamically significant occlusion of a cerebral artery in an acute ischemic stroke is mostly due to thrombus formation, an embolus, and / or other unwanted matter.[000...

AI Technical Summary

Benefits of technology

[0006]Embodiments of the invention provide improved medical devices, systems, and methods. Many of the devices and systems described herein will be beneficial for removal of thrombus from blood vessels, particularly for mitigating neurological damage associated with ischemic stroke. Thrombus associated with ischemic stroke can include a tough, resilient material that can be difficult to break-up, capture within a stent-like cage, or the like. Hence, removal of the material may be facilitated by laterally engaging the material with an expandable member so as to allow the thrombus to be safely pulled into a retrieval catheter. Rather than relying entirely on self-expansion, many embodiments will include expandable members that are configured to controllably expand so as to laterally engage the thrombus with a controlled and variable engagement force. The thrombus may be pulled proximally a significant distance along the vessel from an initial distal position before it can be captured in a retrieval catheter at a proximal position, with the vessel often increasing significantly in diameter, branching, and / or having significant bends between the proximal and distal positions. By allowing a physician to vary thrombus-engagement forces from outside the patient as the thrombus moves, use of the device allows the physician to adjust as appropriate for the changing local conditions along the vessel. Exemplary embodiments of the device include helical and / or braided expandable members coupled with elongate bodies extending proximally from the proximal and distal regions of the expandable members, so that relative movement of the elongate bodies from outside the patient allows controlled actuation of the expandable structure. By providing control over the expansion of the device, the invention may have significant benefits over self-expanding stent-like structures for which expansion forces are dictated by the physical properties of a stent that is only constrained by the thrombus and / or the surrounding vessel.

[0016]In further aspects of the method, the intermediate vessel position can include a bend, and optionally a plurality of bends. Articulating of the elongate device from the first configuration to the second configuration can be performed in response to the expandable member being adjacent the bend, so as to inhibit loss of axially fixed engagement of the expandable member with the thrombus being induced by the bend.

[0017]In further aspects of the method, the intermediate vessel position can include a branch, optionally a plurality of branches. Articulating of the elongate device from the first configuration to the second configuration can be performed in response to the expandable member being adjacent the branch and so as to inhibit loss of axially fixed engagement of the expandable member with the thrombus being induced by the branch.

[0019]In further aspects of the method, the capture catheter can be affixed within the vessel by expanding a toroidal balloon of the capture catheter. The lumen of the capture catheter may have a diameter at least 10% smaller than that of the proximal position, optionally being at least 20% and in some cases being at least 30% smaller. Actuation of the expandable member may help withdraw the thrombus into the capture catheter.

[0034]In further aspects of the method, the second engagement force can maintain or increase the slope angle.

Problems solved by technology

Stroke is a leading cause of disability, death and health care expenditure.

When an artery is obstructed by thrombus, tissue ischemia (i.e. lack of oxygen and nutrients) quickly develops.

Drug-based treatments can be used to dissolve the thrombus, but may take hours to take effect.

While often effective, known thrombus-removal devices, systems, and methods suffer from significant limitations.

Even when the correct size device is initially selected to initially secure the thrombus, the device may not be ideal for moving the thrombus into the retrieval catheter, particularly if the retrieval catheter is positioned at a significant distance from a difficult-to-remove thrombus mass, when the vessel varies in size, has one or more bends, and / or has one or more branches between the thrombus and the retrieval catheter.

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