Electrostatic Vascular Filters

Abstract

An intravascular filter is constructed to electrostatically capture and retain particles of a targeted type (for example fat or methacrylate emboli), even if those particles are physically small enough to slip through the filter in the absence of electrostatic attraction. Specific types of targeted particles are thereby captured and retained with improved efficiency, while permitting free flow of non-targeted particles. This improvement permits intravascular filters to be constructed with low-resistance, widely spaced filter elements. Accordingly, more targeted particles are captured, less thrombosis occurs, less pressure drop occurs across the filter, and perfusion or blood collection in downstream areas is maintained.

1 . A method for filtering embolic material with an electrostatic charge from a vessel of a subject, the method comprising the steps of:
 providing a filter system comprising a first filtration element configured to carry a stable electrostatic charge;   delivering said filter system to a treatment site within a vessel of a subject;   deploying said filter system by expanding the filter system from a low-profile insertion configuration to an expanded-profile filter configuration within the vessel;   electrostatically trapping oppositely charged electrostatic particles in the vessel to the first filtration element with the electrostatic charge.   
     
     
         2 . (canceled) 
     
     
         3 . The method according to  claim 1  wherein said first filtration element is delivered to the vessel in a lumen of an elongate catheter in the low-profile configuration. 
     
     
         4 . (canceled) 
     
     
         5 . The method of  claim 1 , wherein the first filtration element comprises a filtration mesh configured to collapse to prevent the escape of electrostatically trapped particles during removal of said filter system from the vessel. 
     
     
         6 . The method of  claim 5  further comprising, removing the filter system from the vessel by withdrawing the filter system into a lumen of an elongate catheter and wherein a purse string is configured to collapse the first filtration element to a delivery configuration so as to facilitate the withdrawing of the filter system into the lumen. 
     
     
         7 . The method of  claim 1  wherein the first filtration element is configured to carry a negative electrostatic charge such that positive charged electrostatic particles may be electrostatically trapped and removed from the vessel and negative charged electrostatic particles may be repelled from the first filtration element to remain in the vessel. 
     
     
         8 . The method of  claim 1  wherein the first filtration element is configured to carry a positive electrostatic charge such that negative charged electrostatic particles may be electrostatically trapped and removed from the vessel. 
     
     
         9 . The method of  claim 1  wherein the first filtration element comprises a filtration mesh having perforations and wherein a portion of the electrostatically trapped particles are smaller than the perforations of the filtration mesh. 
     
     
         10 . The method of  claim 1  wherein the first filtration element is elongate and configured such that the blood flows parallel to the filtration element with low resistance when the filter system is deployed. 
     
     
         11 . The method of  claim 1 , wherein the filter system further comprises a second filtration element adjacent to the first filtration element, the second filtration element configured to carry a stable electrostatic charge opposite the electrostatic charge of the first filtration element; and
 the method further comprising electrostatically trapping oppositely charged electrostatic particles in the vessel to the second filtration element with the electrostatic charge.   
     
     
         12 . The method of  claim 1  further comprising imparting an electrostatic charge on the first filtration element with a direct current. 
     
     
         13 . The method of  claim 12  wherein the direct current is supplied by a battery. 
     
     
         14 . The method of  claim 12  wherein the electrostatic charge is imparted on the first filtration element by coupling an anode or cathode to the first filtration element. 
     
     
         15 . The method of  claim 12  wherein the electrostatic charge is imparted on the first filtration element by coupling a anode or cathode to the first filtration element and an oppositely corresponding anode or cathode is coupled to an intravascular location. 
     
     
         16 . A method for filtering electrostatically charged particles from blood flow in a blood vessel, the method comprising:
 delivering an intravascular filter comprising one or more filtration elements to a treatment site in the blood vessel;   deploying the intravascular filter by expanding the filter from a low-profile insertion configuration to an expanded-profile filter configuration within the blood vessel;   imparting a stable electrostatic charge on the one or more filtration elements;   maintaining the stable electrostatic charge on the one or more filtration elements while the one or more filtration elements are in the blood vessel; and   electrostatically trapping particles in the blood vessel which have an opposite electrostatic charge to the one or more filtration elements using the imparted electrostatic charge.   
     
     
         17 . The method of  claim 16 , wherein the one or more filtration elements comprise elongate filtration elements and wherein the blood flows parallel to the one or more filtration elements with low resistance. 
     
     
         18 . The method of  claim 17 , wherein the intravascular filter comprises at least two elongate filtration elements adjacent to one another. 
     
     
         19 . The method of  claim 16 , wherein the filtration element comprises a filtration mesh with pore sizes larger than a targeted electrostatic particle size. 
     
     
         20 . A method for removing positive charged particles from blood flow in a blood vessel, the method comprising:
 delivering an intravascular filter comprising a filtration element to a treatment site in the blood vessel;   imparting a stable negative electrostatic charge on the filtration element;   maintaining the stable negative electrostatic charge on the filtration element while the filtration element is in the blood vessel;   electrostatically trapping particles in blood flowing in the blood vessel which have a positive electrostatic charge to the filtration element using the imparted negative electrostatic charge; and   withdrawing the intravascular filter from the treatment site so as to remove the electrostatically trapped particles.