Intravascular stent with increasing coating retaining capacity

Abstract

An expandable stent includes a tubular structure with an outer surface positionable adjacent to a vessel wall and an inner surface facing a lumen of a body passageway. The tubular structure further includes a plurality of expansion struts, connector struts and cells. The tubular structure has a first diameter which permits intraluminal delivery of the tubular structure into the body passageway, and a second expanded and deformed diameter which is achieved upon the application of a radially, outwardly extending force. A plurality of cavities are formed in the outer surface of the stent.

What is claimed is:  
     
         1 . An expandable stent, comprising: 
 a tubular structure including an outer surface positionable adjacent to a vessel wall, an inner surface facing a lumen of a body passageway, a plurality of expansion struts, connector struts and cells, the tubular structure having a first diameter which permits intraluminal delivery of the tubular structure into the body passageway having a lumen, and a second expanded and deformed diameter upon the application from the interior of the tubular member of a radially, outwardly extending force; and    a plurality of cavities formed in the outer surface of the stent.    
     
     
         2 . The stent of  claim 1 , wherein the tubular structure is balloon expandable.  
     
     
         3 . The stent of  claim 1 , wherein the tubular structure is self-expandable.  
     
     
         4 . The stent of  claim 1 , wherein at least a portion of the tubular structure is made of a shape memory alloy.  
     
     
         5 . The stent of  claim 1 , wherein the plurality of cavities are substantially evenly positioned on the tubular structure.  
     
     
         6 . The stent of  claim 1  wherein the plurality of cavities increase a flexibility of the stent without substantially reducing a radial strength of the stent in a deployed state.  
     
     
         7 . The stent of  claim 1 , wherein the plurality of cavities are micro-holes that extend from the outer surface.  
     
     
         8 . The stent of  claim 7 , wherein the micro-holes have a cross-section that is smaller than a cross section of a strut.  
     
     
         9 . The stent of  claim 7 , wherein the micro-holes extend from the outer surface through the inner surface.  
     
     
         10 . The stent of  claim 7 , wherein the micro-holes extend from the outer surface to an interior of the tubular structure without extending through the inner surface.  
     
     
         11 . The stent of  claim 7 , wherein at least a portion of the micro-holes extend from the outer surface through the inner surface and at least a portion extend from the outer surface to an interior of the tubular structure without extending through the inner surface.  
     
     
         12 . The stent of  claim 7 , wherein at least a portion of the micro-holes have geometry's that are configured to provide a reservoir for a coating substance applied to the tubular structure.  
     
     
         13 . The stent of  claim 7 , wherein at least a portion of the micro-holes have a diameter of at least 0.0007 inch.  
     
     
         14 . The stent of  claim 7 , wherein at least a portion of the micro-holes extend perpendicular from the outer surface to an interior of the tubular structure.  
     
     
         15 . The stent of  claim 7 , wherein at least a portion of the micro-holes extend at a non-perpendicular slant angle from the outer surface to an interior of the tubular structure.  
     
     
         16 . The stent of  claim 1 , wherein the plurality of cavities are micro-slits that extend from the outer surface.  
     
     
         17 . The stent of  claim 16 , wherein the micro-slits have a cross-section that is smaller than a cross section of a strut.  
     
     
         18 . The stent of  claim 16 , wherein the micro-slits extend from the outer surface through the inner surface.  
     
     
         19 . The stent of  claim 16 , wherein the micro-slits extend from the outer surface to an interior of the tubular structure without extending through the inner surface.  
     
     
         20 . The stent of  claim 16 , wherein at least a portion of the micro-slits extend from the outer surface through the inner surface and at least a portion extend from the outer surface to an interior of the tubular structure without extending 4 through the inner surface  
     
     
         21 . The stent of  claim 16 , wherein at least a portion of the micro-slits have geometry's that are configured to provide a reservoir for a coating substance applied to the tubular structure.  
     
     
         22 . The stent of  claim 16 , wherein at least a portion of the micro-slits have a width of at least 0.0007 inch.  
     
     
         23 . The stent of  claim 16 , wherein at least a portion of the micro slits have a width greater than 0.0007 inch.  
     
     
         24 . The stent of  claim 16 , wherein at least a portion of the micro slits have a length of at least 0.001 inch.  
     
     
         25 . The stent of  claim 16 , wherein at least a portion of the micro slits have a length greater than 0.001 inch.  
     
     
         26 . The stent of  claim 16 , wherein at least a portion of the micro-slits extend perpendicular from the outer surface to an interior of the tubular structure.  
     
     
         27 . The stent of  claim 16 , wherein at least a portion of the micro-slits extend at a non-perpendicular slant angle from the outer surface to an interior of the tubular structure.  
     
     
         28 . The stent of  claim 16 , wherein at least a portion of the micro-slits have a linear geometric shape.  
     
     
         29 . The stent of  claim 16 , wherein at least a portion of the micro-slits have a curved geometric shape.  
     
     
         30 . The stent of  claim 16 , wherein at least a portion of the micro-slits have a bottom surface formed in an interior of the tubular structure.  
     
     
         31 . The stent of  claim 30 , further including at least one aperture that extends from the bottom surface of a micro-slit through the inner surface.  
     
     
         32 . The stent of  claim 30 , further including a plurality of apertures that extend from the bottom surface of the micro-slit through the inner surface.  
     
     
         33 . The stent of  claim 1 , further comprising: 
 a coating substance on at least a portion of outer surface of the stent including 
 at least a portion of the plurality of cavities.  
   
     
     
         34 . The stent of  claim 33 , wherein the coating substance is a restenosis inhibiting agent.  
     
     
         35 . The stent of  claim 34 , wherein the restenonis inhibiting agent is selected from a drug, polymer and bio-engineered material.  
     
     
         36 . The stent of  claim 34 , wherein the restenonis inhibiting agent is a combination of two agents selected from a drug, polymer and bio-engineered material.  
     
     
         37 . The stent of  claim 34 , wherein each of a cavity of the plurality of cavities is configured to have a shape adapted to increase an amount of restenosis inhibiting agent coated on the stent.  
     
     
         38 . The stent of  claim 33 , wherein each of a cavity of the plurality of cavities is configured to have a shape adapted to provide reservoir of the coated substance on the stent.  
     
     
         39 . An expandable stent, comprising: 
 a tubular structure including an outer surface positionable adjacent to a vessel wall, an inner surface facing a lumen of a body passageway, a plurality of expansion struts, connector struts and cells, the tubular structure having a first diameter which permits intraluminal delivery of the tubular structure into the body passageway having a lumen, and a second expanded and deformed diameter upon the application from the interior of the tubular member of a radially, outwardly extending force;    a plurality of cavities formed in the outer surface of the stent; and    a coating substance on at least a portion of outer surface of the stent including and extending into at least a portion of the cavities.    
     
     
         40 . The stent of  claim 39 , wherein the coating substance is on at least a portion of the inner surface of the stent.  
     
     
         41 . The stent of  claim 39 , wherein the coating substance is a restenosis inhibiting agent.  
     
     
         42 . The stent of  claim 41 , wherein the restenonis inhibiting agent is selected from a drug, polymer and bio-engineered material.  
     
     
         43 . The stent of  claim 34 , wherein the restenonis inhibiting agent is a combination of two agents selected from a drug, polymer and bio-engineered material.  
     
     
         44 . The stent of  claim 40 , wherein each of a cavity of the plurality of cavities is configured to have a shape adapted to increase an amount of restenosis inhibiting agent coated on the stent.  
     
     
         45 . The stent of  claim 39 , wherein each of a cavity of the plurality of cavities is configured to have a shape adapted to provide a reservoir of the coated substance on the stent.  
     
     
         46 . The stent of  claim 39 , wherein the tubular structure is balloon expandable.  
     
     
         47 . The stent of  claim 39 , wherein the tubular structure is self-expandable.  
     
     
         48 . The stent of  claim 39 , wherein at least a portion of the tubular structure is made of a shape memory alloy.  
     
     
         49 . The stent of  claim 39 , wherein the plurality of cavities are substantially evenly positioned on the tubular structure.  
     
     
         50 . The stent of  claim 39 , wherein the plurality of cavities increase a flexibility of the stent without substantially reducing a radial strength of the stent in a deployed state.  
     
     
         51 . The stent of  claim 39 , wherein the plurality of cavities are micro-holes that extend from the outer surface.  
     
     
         52 . The stent of  claim 51 , wherein the micro-holes have a cross-section that is smaller than a cross section of a strut.  
     
     
         53 . The stent of  claim 39 , wherein the plurality of cavities are micro-slits that extend from the outer surface.  
     
     
         54 . The stent of  claim 55 , wherein the micro-slits have a cross-section that is smaller than a cross section of a strut.  
     
     
         55 . A stent assembly, comprising: 
 a balloon; and    an expandable stent positioned at an exterior of the balloon, the stent including, 
 a tubular structure including an outer surface positionable adjacent to a vessel wall, an inner surface facing a lumen of a body passageway, a plurality of expansion struts, connector struts and cells, the tubular structure having a first diameter which permits intraluminal delivery of the tubular structure into the body passageway having a lumen, and a second expanded and deformed diameter upon the application from the interior of the tubular member of a radially, outwardly extending force applied by the balloon;  
 a plurality of cavities formed in the outer surface of the stent; and  
 a coating substance on at least a portion of outer surface of the stent including and extending into at least a portion of the cavities.  
   
     
     
         56 . The stent of  claim 55 , wherein the coating substance is on at least a portion of the inner surface of the stent.  
     
     
         57 . The stent of  claim 55 , wherein the coating substance is a restenosis inhibiting agent.  
     
     
         58 . The stent of  claim 55 , wherein the restenonis inhibiting agent is selected from a drug, polymer and bio-engineered material.  
     
     
         59 . The stent of  claim 55 , wherein each of a cavity of the plurality of cavities is configured to have a shape adapted to increase an amount of restenosis inhibiting agent coated on the stent.  
     
     
         60 . The stent of  claim 55 , wherein each of a cavity of the plurality of cavities is configured to have a shape adapted to provide a reservoir of the coated substance on the stent.  
     
     
         61 . A method of manufacturing an intravascular stent, comprising: 
 forming an intravascular stent having an inner surface and an outer surface; and    forming a plurality of cavities on the outer surface of the intravascular stent; and    disposing on at least a portion of the outer surface and at least a portion of the plurality of cavities a coating substance that inhibits restenosis.    
     
     
         62 . The method of  claim 61 , wherein at least a portion of the plurality of cavities is formed on the outer surface of the intravascular stent by a laser.  
     
     
         63 . The method of  claim 61 , wherein the at least a portion of the plurality of cavities is formed on the outer surface of the intravascular stent by EDM.  
     
     
         64 . The method of  claim 61 , wherein the at least a portion of the plurality of cavities is photochemically formed on the outer surface of the intravascular stent.