Apparatus and method for formation of foil-shaped stent struts

Abstract

A device and method is disclosed for reducing turbulent blood flow over stent struts of an intravascular stent implanted in, for example, a coronary artery. An abrasive slurry is passed over the struts of an intravascular stent in order to remove a portion of the stent struts to form an airfoil shape. When the stent having airfoil-shaped struts is implanted in an artery, the flow of blood over the airfoil shape will reduce the likelihood of turbulent blood flow and thereby will reduce the likelihood of turbulent blood flow and thereby reduce the likelihood of a buildup in plaque or injury to the vessel wall.

1 . A method for forming a stent, comprising:
 providing a metallic stent having a cylindrical shape and a pattern of stent struts;   placing the stent in a chamber;   injecting an abrasive slurry through the chamber and through a lumen of the stent;   removing metal from an inner surface of at least one of the stent struts by the abrasive slurry flowing over the inner surface of the stent.   
     
     
         2 . The method of  claim 1 , wherein as the abrasive slurry flows over the inner surface of the at least one stent strut, a transverse cross-section of the strut is transformed from a substantially rectangular shape into the shape of an airfoil. 
     
     
         3 . The method of  claim 1 , wherein the abrasive slurry has a low viscosity so that it flows through the stent lumen without bending the stent struts. 
     
     
         4 . (canceled) 
     
     
         5 . The method of  claim 1 , wherein the abrasive slurry has a pressure range of 1500 psi to 3500 psi. 
     
     
         6 . The method of  claim 1 , wherein the abrasive slurry contains abrasive particles having an average particle in the range of 12.0 microns (0.0005 inch) to 6.5 microns (0.0003 inch). 
     
     
         7 . The method of  claim 1 , wherein the abrasive slurry contains a polymer. 
     
     
         8 . The method of  claim 1 , wherein the airfoil-shaped cross-section of the at least one stent strut has a first edge that is thinner than a second edge. 
     
     
         9 . The method of  claim 7 , wherein the at least one stent strut has a curved inner surface that extends between the first edge and the second edge. 
     
     
         10 . The method of  claim 7 , wherein as the abrasive slurry flows over the inner surface of the at least one stent strut, the slurry flows in a direction from the first edge toward the second edge. 
     
     
         11 . The method of  claim 9 , wherein the abrasive slurry removes more metal from the first edge than from the second edge. 
     
     
         12 . The method of  claim 2 , wherein the transverse cross-sectional shape of the at least one stent strut before flowing the abrasive slurry over the inner surface is substantially rectangular with radiused corners. 
     
     
         13 . The method of  claim 1 , wherein the metal removed from the at least one stent strut reduces the radial thickness of the first edge from about 5% to about 20% and the second edge from about 3% to about 15%. 
     
     
         14 . The method of  claim 1 , wherein the stent has an outer surface and a radial thickness defined by the outer surface and the inner surface, the radial thickness being in a range of 0.002 inch to 0.060 inch.