Effects of prostaglandin E1 infusion on limb hemodynamics and vasodilatory response in patients with arteriosclerosis obliterans.
It is well known that prostaglandin E1 (PGE1) increases peripheral blood flow. The aim of this study was to investigate the effects of PGE1 infusion on the hemodynamics and vasodilatory response of the leg affected by intermittent claudication in patients with arteriosclerosis obliterans (ASO). Fourteen legs of 8 male patients with ASO were infused intravenously with PGE1 (120 microg/day) for 7 consecutive days. Before the infusion and 5 days after cessation of the infusion, resting skin and skeletal muscle blood flow in the calf and occlusion-induced reactive hyperemic flow were measured using plethysmography and a laser Doppler flowmeter. Clinical symptoms in the legs were assessed by treadmill exercise testing. Resting calf blood flow was found to have increased significantly (skin, from 2.6 +/- 0.1 ml/min/100 g tissue to 2.9 +/- 0.1 ml/min/100 g tissue, p < 0.02; skeletal muscle, from 3.1 +/- 0.2 ml/min/dl tissue to 4.0 +/- 0.5 ml/min/dl tissue, p < 0.02). There was also a significant reduction in the peripheral vascular resistance (-17.8 +/- 7.2%, p < 0.05) 5 days after the cessation of infusion. The time to the half-maximum post peak of hyperemia was significantly elongated (from 34.6 +/- 5.7 sec to 58.6 +/- 9.2 sec, p < 0.01). Borg's score of the legs on exercise testing was markedly reduced, and symptom-free walking distance was increased by an average of 70.9 + 15.6%. In conclusion, PGE1 infusion has vascular effects on not only resting calf blood flow but also hyperemic flow responses. These retentive effects may be due to alteration in vascular functions and/or rheological state as a result of PGE1-induced regular enhancement of blood flow, rather than the direct vasodilatory effect of the agent.