Coated endovascular stent

Abstract

An implantable stent is coated with a material that attracts heparin and with which heparin forms a bond. The stent is exposed to a heparin containing solution just prior to implantation or is first implanted and then exposed to heparinized blood. As heparin becomes detached from the stent, the implantation site is exposed to heparin to restore an effective level and thereby prevent thrombosis.

1 . A method of making a medical device comprising: 
 providing an implantable support structure;    depositing a coating on the support structure, the coating including functional groups that attract heparin;    implanting the support structure in the patient's vasculature; and    exposing the implanted support structure to heparinized blood such that heparin attaches to the coating.    
   
   
       2 . The method of  claim 1 , wherein heparin attaches to the coating via ionic bonds.  
   
   
       3 . The method of  claim 1 , wherein exposing the implantable support structure to heparinized blood comprises delivering heparin from a catheter to the patient.  
   
   
       4 . The method of  claim 1 , wherein the coating is deposited on the entire support structure.  
   
   
       5 . The method of  claim 1 , wherein the support structure is configured such that upon implantation in a blood vessel, such support structure has surfaces that face the vessel walls and surfaces that face the blood flow and wherein the coating is exclusively deposited on the surfaces that face the blood flow.  
   
   
       6 . The method of  claim 1 , wherein the support structure is configured such that upon implantation in a blood vessel, such support structure has surfaces that face the vessel walls, surfaces that face the blood flow and an upstream edge and a downstream edge and wherein the coating is exclusively deposited on at least one of the edges.  
   
   
       7 . The method of  claim 1 , wherein the coating is deposited on the support structure by dipping, spraying or molding.  
   
   
       8 . The method of  claim 1 , wherein the coating is deposited on the support structure by plasma deposition.  
   
   
       9 . The method of  claim 1 , wherein the coating is deposited by first depositing a base layer, selected for its ability to adhere to the support structure and then depositing thereon a top layer selected for its ability to bond to the base layer and avail the functional groups for attachment to the heparin.  
   
   
       10 . The method of  claim 1 , further comprising repeatedly exposing the implanted support structure to heparinized blood in order to maintain a heparin level on the stent.  
   
   
       11 . The method of  claim 1 , wherein the functional groups are selected from a group consisting of amine and carboxyl groups.  
   
   
       12 . A method of making a medical device, comprising: 
 providing an implantable support structure;    depositing a coating on the support structure, the coating including functional groups that attract heparin, bond with heparin, or a combination thereof,    when the coating is exposed to heparin;    sterilizing and storing the support structure having the coating deposited thereon;    exposing the coated support structure to a heparin-containing solution; and    implanting the structure in the patient's vasculature.    
   
   
       13 . The method of  claim 12 , wherein the coating is deposited on the entire support structure.  
   
   
       14 . The method of  claim 12 , wherein the support structure is configured such that upon implantation in a blood vessel, such support structure has surfaces that face the vessel walls and surfaces that face the blood flow and wherein the coating is exclusively deposited on the surfaces that face the blood flow.  
   
   
       15 . The method of  claim 12 , wherein the support structure is configured such that upon implantation in a blood vessel, such support structure has surfaces that face the vessel walls, surfaces that face the blood flow and an upstream edge and a downstream edge and wherein the coating is exclusively deposited on at least one of the edges.  
   
   
       16 . The method of  claim 12 , wherein the coating is deposited on the support structure by dipping, spraying or molding.  
   
   
       17 . The method of  claim 12 , wherein the coating is deposited on the support structure by plasma deposition.  
   
   
       18 . The method of  claim 12 , wherein the coating is deposited by first depositing a base layer, selected for its ability to adhere to the support structure and then depositing thereon a top layer selected for its ability to bond to the base layer and avail the functional groups for attachment to the heparin.  
   
   
       19 . The method of  claim 12 , further comprising exposing the implanted support structure to heparinized blood in order to maintain a heparin level on the support structure.  
   
   
       20 . The method of  claim 12 , wherein the functional groups are selected from a group consisting of amine and carboxyl groups.  
   
   
       21 . The method of  claim 12 , wherein the bonding of the coating with heparin comprises a combination of ionic bonding and covalent bonding.  
   
   
       22 . The method of  claim 12 , wherein the support structure comprises a stent.