Prostacyclin for acute coronary insufficiency.

We have studied the effects of prostacyclin (PGI2) infusions in two different types of angina pectoris, i.e. effort and spontaneous angina. Contrary to sublingual nitroglycerin, intravenous infusions of PGI2 at a dose of 5 or 10 ng/kg/min offered no protection against effort anginal attacks precipitated by atrial pacing. On the other hand, in recurrent attacks of spontaneous angina at rest, infusion of PGI2 at a dose of 5 ng/kg/min led to sustained and long-lasting improvement as manifested by reduction of both anginal attacks and nitroglycerin intake. Different pathogenic mechanisms underlying the two types of angina studied could explain the results obtained. Prostacyclin might be of threapeutic interest in attacks of angina pectoris precipitated by redution of oxygen delivery to the myocardium rather than increased oxygen demand.