Abstract
Polymeric durg delivery systems that allow the application of substances to a localized region for specified periods of time have been developed. After endothelial injury using a balloon catheter technique in 10 rats, the adventitial surface of the carotid artery was exposed to the polymer polyvinyl alcohol (PVA) containing heparin (heparin/PVA) and was compared with exposure to PVA alone in the contralateral(control) vessel. Morphometric analysis of the cross-sectional thrombus : lumen ratio in 10 rats 90 minutes after endothelial injury showed a significant reduction(P<0.005) in thrombus size for treated vessels (4.1±9.6%) compared with control vessels(60.2±25.8%) in the study for intravascular thrombosis. Segmental endothelial desquamation of the common carotid artery in 30 rats produced consistent proliferation of intimal smooth muscle cells from 5 to 20 days after injury. 15 animals were treated with heparin/PVA and PVA alone applied to 15 control rats in a similar fashion as described above. At all time periods, there was a significant reduction in intimal cross sectional area in heparin/PVA-treated vessels compared to control vessels. In the both studies for intravascular thrombosis and intimal proliferation, femoral venous prothrombin time and partial thromboplastin time were unchanged in heparin/PVA-treated animals compared to controls.
