INHIBITION OF PLATELET DEPOSITION WITH LOCAL-DELIVERY OF HEPARIN USING A DOUBLE-BALLOON CATHETER

Heparin is an effective agent in the treatment of unstable angina and myocardial infarction. The clinical utility of heparin is limited by b leeding complications. This study was performed to determine whether s tatic delivery of heparin could effectively inhibit further platelet d eposition. Thrombogenic graft segments were incorporated into chronic arteriovenous shunts in pigs. Autologous platelets were labeled with ( 111)Indium. Platelet deposition was quantitated with gamma camera imag ing. The grafts were exposed to blood flow for 15 min in order to indu ce platelet deposition on the thrombogenic surface. Heparin was delive red locally either by direct exposure or with a double balloon cathete r. After a 15 minute exposure period, the heparin solution was removed and subsequent platelet deposition was monitored for 90 minutes. Hepa rin, administered with the double balloon catheter in doses as low as 12.5 U, effectively inhibited further platelet deposition. An intraven ous injection of 100 U of heparin, the highest dose use for local deli very, did not perturb bleeding time or the activated partial thrombopl astin time. In conclusion, platelet deposition can be inhibited with s tatic local delivery of heparin at doses that are not associated with systemic bleeding. (C) 1997 Elsevier Science Ltd.