ISOSORBIDE DINITRATE DOES NOT INTERFERE WITH HEPARIN ANTICOAGULATION - A PLACEBO-CONTROLLED COMPARISON WITH NITROGLYCERIN IN PATIENTS SCHEDULED FOR CORONARY-ARTERY SURGERY

The possible nitrate-induced heparin resistance was studied intraopera tively in 40 patients undergoing coronary artery bypass grafting. The patients were randomized to receive a continuous infusion of placebo, nitroglycerin (0.5 mu g kg(-1) min(-1)) or isosorbide dinitrate (0.5 o r 2.5 mu g kg(-1) min(-1)). After the infusion had been administered, prior to the institution of cardiopulmonary bypass, for al least 60 mi n, porcine intestine heparin 300 I.U. kg(-1) (as divided in two consec utive doses of 100 and 200 I.U. kg(-1), respectively) was administered to achieve systemic anticoagulation. Activated coagulation time value s and plasma heparin anti-X(i), activity showed no significant differe nces between the groups before and after tile administration of hepari n. It is concluded that in doses given in the present study, organic n itrates do not interfere with the anticoagulation effect of large dose s of heparin required for the conduction of cardiopulmonary bypass.