HEPARIN-RELEASABLE ENDOTHELIAL CELL-ASSOCIATED TISSUE FACTOR PATHWAY INHIBITOR (TFPI) IS INCREASED IN THE CORONARY CIRCULATION AFTER CORONARY SPASM IN PATIENTS WITH CORONARY SPASTIC ANGINA

Tissue factor pathway inhibitor (TFPI) is a physiological regulator of the extrinsic coagulation cascade. Coronary spasm can alter endotheli al cell properties in the coronary artery with resultant thrombosis. T o determine whether coronary spasm affects plasma TFPI level, we measu red the heparin-releasable endothelial cell-associated TFPI (heparin-r eleasable TFPI) (ng/ml) in the coronary sinus and the aortic root befo re and after coronary spasm induced by an injection of acetylcholine i n 18 patients with coronary spastic angina, and before and after myoca rdial ischemia induced by rapid atrial pacing in 18 patients with stab le exertional angina, and in 17 control subjects with normal coronary arteries and no coronary spasm. Heparin-releasable TFPI level in the c oronary spastic angina group significantly increased in the coronary s inus (122+/-46 to 147+/-63, p<0.001) after the ischemic event but not in the aortic root (113+/-44 to 121+/-58). The level in the coronary s inus and the aortic root remained unchanged after the ischemic event i n the stable exertional angina group and after the injection of acetyl choline in the control group. The coronary sinus-arterial difference i n the amount of the heparin-releasable TFPI significantly increased af ter the ischemic event only in the coronary spastic angina group (10+/ -18 to 26+/-18, p<0.002). Our result suggested that heparin-releasable TFPI is increased in the coronary circulation after coronary spasm. ( C) 1998 Elsevier Science Ltd.