COMPARATIVE ACUTE EFFECTS OF ADENOSINE AND PROSTACYCLIN IN PRIMARY PULMONARY-HYPERTENSION

Vasodilators have been a main focus of therapy for primary pulmonary h ypertension, Adenosine and prostacyclin have been shown to reduce pulm onary vascular resistance acutely in these patients, In order to compa re the acute hemodynamic effects of adenosine and prostacyclin, ten pa tients with severe primary pulmonary hypertension, unresponsive to med ical therapy, were studied, After baseline hemodynamics were obtained, an adenosine infusion, 50 to 100 ng/kg/min, was begun and titrated to the maximum tolerated dose, Hemodynamics were allowed to return to ba seline, and thereafter, a prostacyclin infusion was begun at 2 ng/kg/m in, and titrated to the maximum tolerated dose, Overall, adenosine (20 0 +/- 53 ng/kg/min) produced a 33 +/- 18% (p<0.001) fall in pulmonary vascular resistance and a 52 +/- 25% (p<0.001) increase in cardiac out put with no effect on pulmonary or systemic arterial pressures. Prosta cyclin (8 +/- 4 ng/kg/min) caused a 22 +/- 18% (p<0.01) fall in pulmon ary vascular resistance and a 25 +/- 26% (p<0.05) increase in cardiac output with a 14 +/- 6% (p<0.001) decrease in systemic arterial pressu re, but no change in pulmonary arterial pressure, The effects of adeno sine and prostacyclin on pulmonary vascular resistance were similar (r =0.70, r(2)=0.49, p=0.02). Adenosine and prostacyclin have similar hem odynamic effects acutely in primary pulmonary hypertension, Adenosine may be useful as a test of the potential for long-term prostacyclin th erapy in patients with primary pulmonary hypertension,