Collapsible and self-expanding cannula for a percutaneous heart pump and method of manufacturing

Abstract

An expandable cannula for a percutaneous heart pump includes a substantially open proximal end, a substantially open distal end and an elongate central portion disposed between the proximal end and the distal end. The elongate central portion has an inner surface and an opposing outer surface. The expandable cannula is made of a shape memory alloy having an austenite finish temperature Af that is at or below the body temperature of a human patient.

1 - 20 . (canceled) 
     
     
         21 . A mechanical circulatory support device for treating a heart condition, the mechanical circulatory support device comprising:
 a self-expanding cannula that is insertable into a vasculature of a patient for advancement through the vasculature to a desired location for treating the heart condition, the self-expanding cannula including an elongate central portion defining a lumen extending between opposing substantially open ends; and   an expandable impeller received in the elongate central portion, the impeller generating a blood flow through the lumen when rotated at a predetermined speed to provide the circulatory support to treat the heart condition;   wherein the self-expanding cannula has an integrated composite structure including a shape memory alloy and a fluid impermeable membrane applied to the elongate central portion; and   wherein the shape memory alloy has an austenite finish temperature Af that is about 37° C. or less.   
     
     
         22 . The mechanical circulatory support device according to  claim 21 , wherein Af is between 5° C. and 30° C. 
     
     
         23 . The mechanical circulatory support device according to  claim 21 , wherein Af is between 10° C. to 25° C. 
     
     
         24 . The mechanical circulatory support device according to  claim 21 , wherein Af is between 10° C. to 20° C. 
     
     
         25 . The mechanical circulatory support device according to  claim 21 , wherein the shape memory alloy is selected from the group consisting of nickel-titanium (nitinol), copper-zinc, copper-zinc-aluminum, copper-aluminum-nickel, and gold-cadmium. 
     
     
         26 . The mechanical circulatory support device according to  claim 21 , wherein the self-expanding cannula has an outer diameter of approximately 3.5 mm when being advanced through the vasculature of the patient. 
     
     
         27 . The mechanical circulatory support device according to  claim 21 , wherein the self-expanding cannula has an outer diameter of approximately 7 mm when the impeller is being rotated. 
     
     
         28 . The mechanical circulatory support device according to  claim 21 , wherein the shape memory alloy has a cage or mesh structure. 
     
     
         29 . The mechanical circulatory support device according to  claim 28 , wherein the cage or mesh structure is at least one of a braided mesh, a woven mesh, or a laser-cut interconnected maze-like pattern. 
     
     
         30 . The mechanical circulatory support device according to  claim 28 , wherein the fluid impermeable membrane encapsulates the cage or mesh structure in the elongate central portion, the encapsulating defining substantially smooth inner and outer surfaces in the self-expandable elongate central portion. 
     
     
         31 . The mechanical circulatory support device according to  claim 28 , wherein the fluid impermeable membrane is applied to the cage or mesh structure in multiple material layers. 
     
     
         32 . The mechanical circulatory support device according to  claim 31 , wherein the multiple material layers are selected from the group consisting of a thermoplastic, segmented polyurethane block copolymer, a poly(ether-b-amide) copolymer, poly(ether ester) block copolymer, a functionalized olefinic thermoplastic elastomer having polar functional groups, a styrenic thermoplastic elastomer functionalized by polar functional groups, and combinations thereof, wherein the polar functional groups are selected from the group consisting of maleic anhydride, acrylate, epoxy, amine, and combinations thereof. 
     
     
         33 . The mechanical circulatory support device according to  claim 31 , wherein the multiple material layers are adhered to one another. 
     
     
         34 . The mechanical circulatory support device according to  claim 33 , wherein the multiple material layers are thermally bonded to one another. 
     
     
         35 . The mechanical circulatory support device according to  claim 33 , wherein the multiple material layers are fused together. 
     
     
         36 . The mechanical circulatory support device according to  claim 33 , wherein the multiple material layers includes at least one layer applied from an inside of the cage or mesh structure and at least one layer applied from an outside of the cage or mesh structure. 
     
     
         37 . The mechanical circulatory support device according to  claim 21 , wherein the substantially open proximal portion and the substantially open distal portion each comprise a plurality of struts. 
     
     
         38 . The mechanical circulatory support device according to  claim 37 , wherein the plurality of struts are fabricated from a shape memory alloy.