772–5 Local Intramural Nitroglycerin Delivery Improves Vascular Responses to Balloon Arterial Injury

Abstract

Endothelial denuding injury of the arterial wall in vivo is associated with a localized platelet deposition and a vasoconstrictive response, that may be due to loss of endogenous vessel wall EDRF nitric oxide production. Exogenous administration of EDRF in the form of systemic nitroglycerin (NTG) can decrease the injury-related platelet deposition and vasoconstriction. Whether the injured vessel wall EDRF effect can be enhanced by local intramural NTG delivery was studied using a Localmed infusion sleeve. Normal pigs underwent carotid arterial injury by a balloon dilatation catheter placed inside a sleeve with distal micro-perforations designed for intramural drug delivery at the site of angioplasty. In 6 pigs, the left carotid was treated with NTG, while the right carotid was treated with dextrose 5% vehicle. Autologous 51 Crplatelet (PLT) deposition quantified at the site of deep arterial injury by the body of the balloon, and the degree of angiographic vasoconstriction (VC) at the site of endothelial denudation by the tapering ends of the balloon, were assessed before and after NTG or dextrose delivery, and are shown below, (mean ± SEM): Group PLT deposition (% control) VC before (% baseline) VC after (% baseline) Dextrose 100 25.7 ± 7.6 25.7 ± 7.6 NTG 59.3 ± 14.0 * 26.2 ± 72 10.7 ± B.6 † * p < 0.05 vs dextrose † p < 0.05 vs VC before Thus, local administration of NTG directly into the injured arterial wall is effective in decreasing platelet deposition and the vasoconstrictive response after deep arterial injury. This may improve vascular function after balloon injury.