Embolic filter

#The present invention relates generally to intravascular devices and systems and more particularly, filter devices which can be used to capture embolic material or thrombi found in blood vessels.

#The intravascular filter device and system of the present invention is particularly useful as a passive device utilized 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. While the filter device and system of the present invention is particularly useful in the cerebral vasculature and neuro-vasculature, the invention can be used in conjunction with any vascular interventional procedure in which there is an embolic risk.

#A variety of non-surgical interventional procedures have been developed over the years for opening stenosed or occluded blood vessels in a patient caused by the build up of plaque or other substances on the wall of the blood vessel. Such procedures usually involve the remote introduction of the interventional device into the lumen of the artery, usually through a catheter. In typical carotid PTA procedures, a guiding catheter or sheath is percutaneously introduced into the cardiovascular system of a patient through the femoral artery and advanced, for example, through the vasculature until the distal end of the guiding catheter is in the common carotid artery. A guidewire and a dilatation catheter having a balloon on the distal end are introduced through the guiding catheter with the guidewire sliding within the dilatation catheter. The guidewire is first advanced out of the guiding catheter into the patient's carotid vasculature and is directed across the arterial lesion. The dilatation catheter is subsequently advanced over the previously advanced guidewire until the dilatation balloon is properly positioned across the arterial lesion. Once in position across the lesion, the expandable balloon is inflated to a predetermined size with a radiopaque liquid at relatively high pressures to radially compress the atherosclerotic plaque of the lesion against the inside of the artery wall and thereby dilate the lumen of the artery. The balloon is then deflated to a small profile so that the dilatation catheter can be withdrawn from the patient's vasculature and the blood flow resumed through the dilated artery. As should be appreciated by those skilled in the art, while the above-described procedure is typical, it is not the only method used in angioplasty.

#FIG. 1 is a side view, partially in cross-section, of a vessel partially occluded by a stenosis and a distal portion of a delivery catheter and intravascular filter device of the present invention positioned proximate the debris;

#FIG. 2 is a side view, partially in cross-section, of the intravascular filter as deployed within the vessel of FIG. 1;

#FIG. 3 is a plan view, depicting a pattern of a preferred embodiment of an intravascular filter of the present invention as if the filter was cut longitudinally and unrolled to show its pattern in a flat configuration;

#Referring now to the drawings, and in particular FIGS. 1 and 2, there is shown a filter device of the present invention. The filter device 20 is adapted to provide more consistent and improved radial opening as well as enhanced angular resistance to collapse. Moreover, the filter device 20 of the present invention is configured to facilitate the maintenance of clearance in its interior space along its length allowing undesired materials or objects found in the blood stream to enter and be captured.

#Furthermore, since it is contemplated that the filter device 20 be manufactured from a tubular member to form elements with very small widths and thicknesses, the device is thus more easily packed to a relatively smaller diameter and inherently embodies high longitudinal flexibility.

#The filter device 20 (FIG. 2) of the present invention includes a body 22 having a proximal end portion 24 and a distal end portion 26. The proximal end portion 24 is intended to be affixed to a terminal end portion of an elongate member 30 (i.e., wire; described in more detail below). In a presently preferred embodiment, the body 22 of the filter device 20 is generally tubular with a proximally directed opening 32 and a generally closed terminal end 34 to thereby form a filter for receiving embolus, stones, thrombus and foreign bodies found in vasculature, which may be free flowing within the blood stream during or as a result of treatment.