Blockage of partially obstructed coronary arteries with platelet thrombi: comparison between its prevention with cyclooxygenase inhibitors versus prostacyclin.

This study shows that in vivo, platelet aggregation occurs by both cyclooxygenase- and noncyclooxygenase-dependent mechanisms, so that blockage of partially obstructed coronary arteries still occurs after cyclooxygenase inhibition if the obstruction is severe enough. Prostacyclin prevents blockage of the vessels under all conditions. Furthermore, prostacyclin's ability to block primary aggregation is enhanced after cyclooxygenase inhibition.