THE ROLE OF NITRIC-OXIDE IN CARDIAC-SURGERY

The release of nitric oxide (NO) from coronary endothelial cells is im paired following reperfusion; however, several experimental studies ha ve found that it exerts a cardioprotective effect during myocardial is chemia-reperfusion, Thus, attempts have been made to supplement NO pro duction exogenously during reperfusion when endogenous NO release may be diminished, Conversely, other studies suggest that NO exacerbates r eperfusion injury by inducing the production of peroxynitrite. NO has also been reported to provide beneficial effects as a selective pulmon ary vasodilator to relieve pulmonary hypertension, A loss of NO-mediat ed relaxation caused by the dysfunction of endothelial cells is charac teristic of intimal hyperplasia, and nitrosovasodilators have proven e fficient against atherosclerotic coronary heart disease, which may be attributable to their antiplatelet effects as well as to vasodilation, Furthermore, protamine sulfate, which is rich in L-arginine, is thoug ht to augment NO production by supplying exogenous L-arginine, or to a ct on endothelial cell receptors to stimulate the production of NO. Th is review summarizes the current role of NO in cardiac surgery.