DOUBLE-BLIND, PLACEBO-CONTROLLED STUDY OF INTRAVENOUS PROSTACYCLIN ON HEMODYNAMICS IN SEVERE RAYNAUDS-PHENOMENON - THE ACUTE VASODILATORY EFFECT IS NOT SUSTAINED

In 12 patients with severe Raynaud's phenomenon (RP: ischemic ulcers or intractable pain despite use of narcotic analgetics), we studied the acute and long-term hemodynamic effects of epoprostenol on systemic and finger skin circulation. Epoprostenol was infused intravenously (i.v., initial infusion rate of 2 ng/kg/min, with a subsequent increase of 2 ng/kg/min every 30 min to the individually tolerated maximal dose of 8 ng/kg/min) in a triple, 5-h, double-blind, placebo-controlled cross-over study. During epoprostenol infusion, systolic blood pressure (SBP) remained stable, while diastolic BP (DBP) decreased (-8 mm Hg, p < 0.02), with a simultaneous increase in heart rate (HR + 14 beats/min, p < 0.001). Forearm blood flow (FBF) increased and forearm vascular resistance (FVR) decreased during epoprostenol as compared with placebo infusion (p < 0.01). Epoprostenol caused a significant increase in fingertip skin temperature (p < 0.01) as well as in laser Doppler flux (p < 0.02) before and after a standardized cooling test of the hand as compared with placebo. The increase in transcutaneous oxygen tension reached significant difference only during recovery (p < 0.02). No long-term improvement was noted during two additional cooling tests performed 1 and 6 weeks after the completed epoprostenol or placebo triple-infusion cycle. Repeated long-lasting epoprostenol infusion immediately improves the microcirculation, but these effects are not sustained after 1 week.