Expandable emboli filter and thrombectomy device

Abstract

Expandable emboli filter and thrombectomy devices adapted for use with microcatheters to remove debris from blood vessels. The devices embody expanded profiles that span the entirety of various sized target vessels and thus are particularly effective in the engagement of debris found in vessels.

Description

BACKGROUND OF THE INVENTION [0001] The present invention relates generally to filtering and thrombectomy devices and systems which can be used to capture embolic material or thrombi found in blood vessels. The filtering devices and systems of the present invention are particularly useful when performing balloon angioplasty, stenting procedures, laser angioplasty or atherectomy in critical vessels where the release of embolic debris into the bloodstream can occlude the flow of oxygenated blood to the brain or other vital organs, which can cause devastating consequences to the patient. The thrombectomy devices are suited for the removal of thrombus in a variety of vessels. While the embolic filtering and thrombectomy devices and systems of the present invention are particularly useful in the cerebral vasculature and neurovasculature, the inventions can be used in conjunction with any vascular interventional procedure in which there is an embolic risk. [0002] A variety of non-surgical ...

AI Technical Summary

Benefits of technology

[0012] Briefly and in general terms, the present invention is directed toward expandable devices for repairing blood vessels. The expandable devices are particularly suited for removing emboli or thrombi from the bloodstream of a human or animal. One significant advantage provided by the present invention is the potential use of the expandable devices in narrow and very distal vasculature.

[0014] In another aspect, the present invention includes multiple loops that are connected by longitudinally extending fibers. The connecting fibers may be crossing or non-crossing and may terminate at a superior loop or continue distally to define a tapered distal end. A catheter is provided for deploying the double loop device as is a tether which effectuates the delivery and withdrawal of the device. The multiple loops are intended to self-expand to occupy the entirety of the cross-section of the blood vessel into which it is deployed, the loops assuming the geometry of the vessel. Additionally, when the device is in its expanded configuration, the tether is intended to generally lie adjacent a wall defining the lumen thereby accomplishing less blood flow obstruction. The distal loops may also provide internal support for an embolic filter, facilitating material entry into the filter.

[0015] In a third aspect of the invention, an embolectomy snare is provided which has the advantage of being able to assume a very small profile when packed within a delivery catheter. The embolectomy snare is characterized by including a basket that is formed from non-overlapping elongate members.

Problems solved by technology

However, there is one common problem which can become associated with all of these types of procedures, namely, the potential release of embolic debris into the bloodstream that can occlude distal vasculature and cause significant health problems to the patient.

Additionally, while complete vaporization of plaque is the intended goal during a laser angioplasty procedure, quite often particles are not fully vaporized and thus enter the bloodstream.

When any of the above-described procedures are performed in the vessels supplying blood to the brain, the release of emboli into the circulatory system can be extremely dangerous and sometimes fatal to the patient.

Naturally occurring debris can also be highly dangerous to a patient.

Debris that is carried by the bloodstream to distal vessels of the brain can cause these cerebral vessels to occlude, resulting in a stroke, and in some cases, death.

Therefore, although cerebral percutaneous transluminal angioplasty has been performed in the past, the number of procedures performed has been limited due to the justifiable fear of causing an embolic stroke should embolic debris enter the bloodstream and block vital downstream blood passages.

However, it is often difficult to control the size of the fragments which are formed, and the potential risk of vessel occlusion still exists, making such a procedure in the carotid arteries a high-risk proposition.

However, as mentioned above, there have been complications with such systems since the vacuum catheter may not always remove all of the embolic material from the bloodstream, and a powerful suction could injure the patient's vasculature or remove more blood than is safe.

Other techniques which have had some limited success include the placement of a filter or trap downstream from the treatment site to capture embolic debris before it reaches the smaller blood vessels downstream.

However, there have been problems associated with conventional filtering systems.

In particular, certain previously developed filtering devices do not optimize the area for embolic collection.

That is, conventional filtering devices may not present a collection device that spans the entity of the vessel or it may include supporting structure that itself impedes emboli collection.

Certain other devices are not effective when used in conjunction with a microcatheter.

However, such devices have been found to have structures which are either highly complex or lacking in sufficient or effective expansion and retraction capabilities.

Disadvantages associated with the devices having highly complex structure include difficulty in manufacturability as well as use in conjunction with microcatheters.

Other less complex devices can pull through clots due to in part the lack of experience in using the same, or lack an adequately fine mesh for capturing clots or foreign bodies.

Furthermore, systems heretofore disclosed in the art are generally limited by size compatibility and the increase in vessel size as the emboli is drawn out from the distal vascular occlusion location to a more proximal location.

If the thrombectomy device is too large for the vessel it will not deploy correctly to capture the clot or foreign body, and if too small in diameter it cannot capture thromboembolic material or foreign bodies across the entire cross section of the blood vessel.

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