Devices for restoring blood flow within blocked vasculature

Abstract

The devices and methods described herein relate to clearing of blockages within body lumens, such as the vasculature, by addressing the frictional resistance on the obstruction prior to attempting to translate and / or mobilize the obstruction within the body lumen.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS [0001] This application is a non-provisional of U.S. Provisional Application No. 60 / 765,496 filed Feb. 03, 2006 which is incorporated by reference in its entirety.FIELD OF THE INVENTION [0002] The devices and methods described herein relate to clearing of blockages within body lumens, such as the vasculature, by addressing the frictional resistance on the obstruction prior to attempting to translate the obstruction within the body lumen. In one variation, the devices and methods described below may treat conditions of ischemic stroke by remove blockages within arteries leading to the brain. Accordingly, variations of such methods and devices must navigate tortuous anatomy and vasculature without causing unacceptable damage to the anatomy. Also, the devices and methods first secure and surround the obstruction (such as a clot) prior to significantly moving the clot within the anatomy. BACKGROUND OF THE INVENTION [0003] Ischemic stroke occurs wh...

AI Technical Summary

Benefits of technology

[0014] In another variation of the device, the device may include a low friction mode (such as a set of parallel wires, or wires extending axially along the lumen or vessel) that converts to an increased friction mode (such as a compressed set of wires acting on the obstruction or a twisted set of wires acting on the obstruction). The increase in friction is an increase in the friction between the obstruction and the device (as opposed to the vessel wall. In some cases, the low friction modes is a low surface area mode and the high friction mode is a high surface area mode. When configured in the low friction mode, the device is better suited to engage the obstruction without the undesirable effect of prematurely mobilizing the obstruction or compacting the obstruction (e.g., when wires are slid across the obstruction in a transverse motion). Upon engaging the obstruction, the device will conform to a high friction mode with respect to the obstruction (in some cases the device will have an increased surface area mode). This high friction mode permits the device to better grip the obstruction for ultimate removal of the obstruction.

[0022] It should be noted that in some variations of the invention, all or some of the filaments (used in the surrounding portion of the device) can be designed to increase their ability to adhere to the obstruction. For example, the filaments of the surrounding portion may be coupled to an energy source (e.g., RF, ultrasonic, or thermal energy) to “weld” to the obstruction. Application of energy to the filaments may allow the surrounding portion to deform into the obstruction and “embed” within the obstruction. Alternatively, the filaments may impart a positive charge to the obstruction to partially liquefy the obstruction sufficiently to allow for easier removal. Alternatively, a negative charge could be applied to further build thombus and nest the device for better pulling force. The filaments may be made stickier by use of a hydrophilic substance(s), or by chemicals that would generate a chemical bond to the surface of the obstruction. Alternatively, the filaments may reduce the temperature of the obstruction to congeal or adhere to the obstruction.

Problems solved by technology

It should be noted that although minimal axial movement of the obstruction may take place, the device surrounds the obstruction before such movement causes significant distortion to the geometry of the obstruction resulting in an increase in the static force required to remove the obstruction from the vessel.

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