Cannula with flow diversion mechanism and methods of use

Abstract

A cannula is described that includes a diverter mechanism in the form of a diffusion surface deployable from within the lumen of the cannula and retractable from the lumen of the cannula. The diffusion surface may take the form of a planar surface, a curved surface, a membrane mounted on a wire ring, or a conical sleeve, or any other suitable shape. In use, the cannula is inserted in a vessel, the diffusion surface is deployed in the lumen of the cannula beyond the distal end of the cannula, and blood flow is passed through the cannula and against the diffusion surface. Alternative devices and methods are also described.

What is claimed is:  
     
         1 . A surgical method, comprising the steps of: 
 inserting a cannula into a blood vessel, the cannula comprising an elongate tubular member having a proximal end, a distal end, and a lumen therebetween;    deploying an embolic protection filter through the elongate tubular member and within the blood vessel;    advancing a diffusion surface from the lumen of the elongate tubular member beyond the distal end of the elongate tubular member;    flowing a blood stream through the lumen of the elongate tubular member against the diffusion surface, wherein the blood stream is dispersed by the diffusion surface; and    retracting the diffusion surface into the lumen of the elongate tubular member.    
     
     
         2 . The method of  claim 1 , wherein the blood vessel is an artery.  
     
     
         3 . The method of  claim 2 , wherein the artery is the aorta.  
     
     
         4 . The method of  claim 1 , wherein the elongate tubular member is angled at its distal end.  
     
     
         5 . The method of  claim 1 , wherein the lumen is divided into more than one lumen.  
     
     
         6 . The method of  claim 1 , further comprising an occlusion member deployable from the distal end of the elongate tubular member.  
     
     
         7 . The method of  claim 1 , wherein the diffusion surface comprises a membrane mounted on a flexible wire ring.  
     
     
         8 . The method of  claim 7 , wherein the membrane is semi-permeable.  
     
     
         9 . The method of  claim 8 , wherein the membrane is a mesh.  
     
     
         10 . The method of  claim 7 , wherein the membrane is impermeable.  
     
     
         11 . The method of  claim 1 , wherein the diffusion surface is a cone-shaped sleeve.  
     
     
         12 . The method of  claim 11 , wherein the sleeve is an elastomeric material.  
     
     
         13 . The method of  claim 1 , wherein the diffusion surface comprises a substantially flat surface mounted at a distal end of a flexible elongate member.  
     
     
         14 . The method of  claim 13 , wherein the flexible elongate member is a wire.  
     
     
         15 . The method of  claim 13 , wherein the surface is attached to the flexible elongate member at substantially a 45° angle.  
     
     
         16 . A cannula, comprising: 
 an elongate tubular member having a proximal end, a distal end, and a lumen therebetween;    an attachment wire coupled to the distal end of the elongate tubular member; and    an expansion frame deployable from the distal end of the elongate tubular member and attached to the distal end of the attachment wire;    wherein during use, the distal end of the elongate tubular member is inserted into a vessel and the expansion frame is expanded to fill the vessel lumen.    
     
     
         17 . The cannula of  claim 16 , further comprising a mesh attached to the expansion frame.  
     
     
         18 . The cannula of  claim 16 , further comprising a diffusion surface deployable from within the lumen of the elongate tubular member and retractable into the lumen of the elongate tubular member.  
     
     
         19 . The cannula of  claim 18 , wherein the diffusion surface comprises a substantially flat surface mounted at a distal end of a flexible elongate member.  
     
     
         20 . The cannula of  claim 16 , wherein the lumen is divided into more than one lumen.