Severe intracoronary thromboxane release preceding acute coronary artery occlusion

Abnormalities of thromboxane (TXA2)-prostacyclin (PGI2) balance have been described in patients with coronary artery disease. Whether these abnormalities precede or follow an acute coronary event is debated. We report a patient in whom spontaneous acute right coronary artery occlusion was observed during coronary angiography. Measurements of arachidonic acid metabolites demonstrated imbalance in TXA2-PGI2 equilibrium preceding coronary occlusion. Marked increase in TXA2 in coronary sinus but not in the aortic blood suggested intracoronary release. Absence of PGI2 in the coronary venous blood at baseline and during tachycardia stress was evidence for failure of atherosclerotic coronary vessels to generate PGI2.