Embolic filter with controlled aperture size distribution

Abstract

Methods and devices are provided for protecting the cerebrovascular circulation from embolic debris released during an index procedure. An embolic protection filter is delivered in a reduced profile configuration via an access catheter, and positioned in the aorta spanning the ostia to the three great vessels leading to the cerebral circulation. An index procedure catheter is thereafter advanced through the same access catheter to conduct the index procedure. The index procedure may be a transcatheter aortic valve replacement. A pore distribution in the filter blocks passage of debris greater than a predetermined threshold, minimizes total cumulative volume of debris passing through the filter and minimizes blood pressure drop across the filter.

1 . (canceled) 
     
     
         2 . An intravascular filter for blocking passage of debris, comprising:
 a self-expandable tubular wire frame, having a tubular sidewall extending axially from a proximal end to a distal end; and   a porous membrane carried by the tubular sidewall, the porous membrane comprising a plurality of electrospun fibers defining a distribution of pore sizes.   
     
     
         3 . The intravascular filter of  claim 2 , wherein the plurality of electrospun fibers extend circumferentially around the self-expandable tubular wire frame. 
     
     
         4 . The intravascular filter of  claim 2 , wherein the electrospun fibers are formed from a dispersion, a solution, a suspension, a liquid, a molten material, a semi-molten material, or a semi-fluid material. 
     
     
         5 . The intravascular filter of  claim 2 , wherein the porous membrane comprises a plurality of layers of the electrospun fibers. 
     
     
         6 . The intravascular filter of  claim 5 , wherein a layer of the plurality of layers has a different average pore size than one of the other layers. 
     
     
         7 . The intravascular filter of  claim 2 , wherein the porous membrane is configured to block passage of all debris having a maximum dimension greater than 80 microns. 
     
     
         8 . The intravascular filter of  claim 2 , wherein the distribution of pore sizes includes a first group of pores with a maximum dimension of no more than 25 microns. 
     
     
         9 . The intravascular filter of  claim 8 , wherein the distribution of pore sizes further includes a second group of pores with a maximum dimension of at least 50 microns. 
     
     
         10 . The intravascular filter of  claim 9 , wherein the first group of pores has at least three times as many pores as the second group of pores. 
     
     
         11 . The intravascular filter of  claim 2 , wherein a sum of an area of all pores of the porous membrane is at least about 30% of a surface area of the porous membrane when the filter is in an unconstrained expansion. 
     
     
         12 . A method of forming an intravascular filter for blocking passage of debris, the method comprising:
 electro spinning a material onto a self-expandable frame; and   forming with the electrospun material a distribution of different sized pores along a length of the frame.   
     
     
         13 . The method of  claim 12 , further comprising expelling the material from one or more orifices of a spinneret. 
     
     
         14 . The method of  claim 13 , further comprising performing a series of passes of the spinneret axially relative to the self-expandable frame. 
     
     
         15 . The method of  claim 12 , further comprising:
 loading the material into a spinneret having one or more orifices on an outside circumference of the spinneret;   expelling the material into a stream from the one or more orifices;   elongating the stream into a small diameter fiber;   depositing the fiber onto the self-expandable frame; and   performing a series of passes of the spinneret axially relative to the self-expandable frame.   
     
     
         16 . The method of  claim 12 , further comprising:
 loading the frame on a mandrel;   rotating the mandrel as the material is electrospun onto the frame.   
     
     
         17 . The method of  claim 12 , further comprising layering the material along the self-expandable frame thereby successively reducing average pore sizes formed between adjacent fibers of the material. 
     
     
         18 . The method of  claim 12 , further comprising coating the frame. 
     
     
         19 . The method of  claim 18 , wherein coating the frame comprises dip coating the frame in polyurethane. 
     
     
         20 . The method of  claim 12 , further comprising forming the frame by weaving one or more wires over a mandrel. 
     
     
         21 . The method of  claim 12 , further comprising forming the frame by welding a series of wires together via axially offset welds down to a single control wire at a proximal end of the frame.