Embolic filter frame having looped support strut elements

Abstract

An improved embolic filter frame having looped support struts. The frame configuration provides enhanced longitudinal compliance, improved sealing against a vessel wall, low profile delivery, and a short deployed length. The looped support struts have a high degree of “radial” stiffness with a low degree of “longitudinal” stiffness. In the deployed state, the frame exerts a relatively high stress onto a vessel wall to maintain an effective seal, yet remains compliant in the longitudinal direction. Minor displacements of the support wire or catheter are therefore not translated to the filter. The looped support struts elongate when tensioned and assume a compressed and essentially linear form. While constrained in this linear state by a delivery catheter, the support struts exert minimal stress onto the delivery system. The overall delivery profile and stiffness are therefore reduced. When the delivery catheter constraint is removed during deployment, the struts “snap open” and assume a looped configuration which exert a high degree of force onto the vessel wall, creating an enhanced filter to vessel wall seal. In addition, the looped struts and the central collar connecting the support struts to the support wire, are positioned essentially within the plane of the filter opening. The overall deployed length of the embolic filter is therefore reduced.

What is claimed is:  
     
         1 . An embolic filter comprising: 
 a support wire;    an embolic filter frame having a filter support portion and multiple support struts mounted to the support wire;    the support struts extending radially from the support wire;    at least one support strut having a looped configuration when not in tension in a deployed state; and    a filter element attached to the filter support portion.    
     
     
         2 . The embolic filter of  claim 1  wherein the multiple support struts have looped configurations.  
     
     
         3 . The embolic filter of  claim 1  wherein at least one support strut projects a looped configuration in two orthogonal views.  
     
     
         4 . The embolic filter of  claim 1  wherein at least one support strut has an “s” shape.  
     
     
         5 . An embolic filter comprising: 
 a support wire having a longitudinal axis;    an embolic filter frame including multiple support struts mounted to the support wire at an attachment point;    the frame having a constrained delivery state and a non-tensioned deployed state;    the embolic filter having a distal and proximal end;    the frame having a filter opening when in the non-tensioned deployed state;    the filter opening defining a plane essentially orthogonal to the support wire longitudinal axis; and    the strut attachment point located distally from the plane of the filter opening.    
     
     
         6 . The embolic filter of  claim 5  further comprising at least three looped support struts.  
     
     
         7 . The embolic filter of  claim 5  wherein at least one support strut projects a looped configuration in two orthogonal views.  
     
     
         8 . An embolic filter comprising: 
 a support wire;    an embolic filter frame including multiple struts mounted to the support wire;    the struts having a constrained delivery state and a non-tensioned deployed state;    the struts having an essentially linear configuration while in the constrained delivery state and an essentially looped configuration while in the non-tensioned deployed state;    wherein the struts are adapted to transform from the straight configuration to the looped configuration during deployment.    
     
     
         9 . The embolic filter of  claim 8  further comprising at least three looped support struts.  
     
     
         10 . The embolic filter of  claim 8  wherein at least one support strut projects a looped configuration in two orthogonal views.  
     
     
         11 . An embolic filter comprising: 
 a support wire;    an embolic filter frame including multiple support struts mounted to the support wire and extending radially therefrom;    the struts having a constrained delivery state and a non-tensioned deployed state;    at least one strut having a loop configuration when in the non-tensioned deployed state; and    a filter element attached to the frame.    
     
     
         12 . The embolic filter of  claim 11  further comprising at least three looped support struts.  
     
     
         13 . The embolic filter of  claim 11  wherein at least one support strut projects a looped configuration in two orthogonal views.  
     
     
         14 . An embolic filter comprising: 
 a movable support wire having a maximum total displacement;    a frame having multiple looped support struts and an unconstrained diameter;    wherein a ratio of the frame unconstrained diameter divided by the support wire total displacement is greater than about 2.    
     
     
         15 . The embolic filter of  claim 14  wherein at least one support strut projects a looped configuration in two orthogonal views.  
     
     
         16 . An embolic filter comprising: 
 a frame having multiple looped support struts, a deployed length and an unconstrained diameter;    wherein the frame deployed length divided by the frame unconstrained diameter is between about 0.5 to about 1.    
     
     
         17 . The embolic filter of  claim 16  wherein at least one support strut projects a looped configuration in two orthogonal views.  
     
     
         18 . An embolic filter comprising: 
 a frame having multiple looped support struts, a constrained delivery length and an unconstrained length; wherein    the frame constrained delivery length divided by the unconstrained frame length is between about 2 to about 3.    
     
     
         19 . The embolic filter of  claim 18  wherein at least one support strut projects a looped configuration in two orthogonal views.  
     
     
         20 . An endoluminal filter assembly comprising 
 a filter element;    a support wire;    a filter frame comprising at least two “s” shaped support struts attaching the filter element to the support wire.    
     
     
         21 . The endoluminal filter assembly of  claim 20  wherein the filter frame is slidably attached to the support wire.  
     
     
         22 . An endoluminal filter assembly comprising 
 a support wire;    a filter frame having a collar adapted to attach around the support wire and move relative thereto;    a first stop attached to the support wire distal to the filter frame;    a second stop attached to the support wire proximal to the filter frame;    wherein movement of the filter frame along the support wire is constrained by the first and second stops.    
     
     
         23 . The endoluminal filter assembly of  claim 22  wherein the filter frame includes at least two looped support struts.