THE DYNAMIC CHANGES OF PLASMA TISSUE-TYPE PLASMINOGEN-ACTIVATOR LEVEL AND THE ACTIVITY OF ITS INHIBITOR DURING CORONARY VASOSPASM

This study aimed to examine the dynamic changes of the fibrinolytic system during coronary vasospasm. Tissue-type plasminogen activator (t-PA), plasminogen activator inhibitor (PAI) and fibrinopeptide A (FPA) levels were measured in the great cardiac venous and arterial blood of 9 patients with clinically and angiographically proven vasospastic angina and 11 controls. Before ergonovine provocation, although there was no difference between the above 2 groups in t-PA levels in the aorta or the great cardiac vein, the PAI level in patients with variant angina was lower than in the controls both in the aorta (4.2 +/- 3.5 IU/ml vs 10.9 +/- 5.2 IU/ml) and in the great cardiac vein (2.3 +/- 2.9 IU/ml vs 11.9 +/- 4.9 IU/ml). During ergonovine-induced coronary vasospasm in patients with variant angina, the t-PA level in the great cardiac vein significantly increased from 3.4 +/- 0.7 ng/ml to 4.4 +/- 0.5 ng/ml (p < 0.05), but it did not change in the aorta. The maximal dose of ergonovine (0.4 mg) induced mild diffuse coronary vasoconstriction in the controls, and this diffuse coronary vasoconstriction induced a reduction of PAI levels in the great cardiac vein from 11.9 +/- 4.9 IU/ml to 9.5 +/- 4.8 IU/ml (p < 0.05). FPA levels in the great cardiac vein did not change during ergonovine-induced coronary vasospasm in either group. Thus, the coronary vasospasm induced the release of t-PA from endothelial cells of coronary vessels and resulted in the reduction in the PAI activity in the great cardiac vein. In conclusion, during coronary vasospasm, the fibrinolytic system seems to play an anti-thrombogenic role in coronary arteries.