Hemodynamics in Shy-Drager Syndrome and Treatment with Indomethacin

Abstract

Hemodynamic studies were performed in a case of Shy-Drager syndrome with severe orthostatic hypotension. Marked depression of blood pressure was recognized immediately after the tilt-up, wherein decrease in cardiac output was detected (65 → 35 ml; stroke volume) during measurements by echocardiography. In association with the depression of blood pressure and decrease in cardiac ouput, Doppler sonograms showed the overall blood flow reduction in the brain-supplying arteries, suggesting some breakdown of autoregulation of the cerebral blood flow. Medication with indomethacin obviously limited the depression of blood pressure during the standing exercise. The pressor mechanism of indomethacin might be regarded as a result of increased vasoconstrictivity by inhibiting the synthesis of prostaglandins.

Abnormal regional blood flow responses during and after exercise in human sympathetic denervation

“…This implies that the leg muscle was a site likely to contribute to the profound fall in systemic vascular resistance. Post exercise in AF there was a slower return of LM blood flow and vascular resistance to baseline, suggesting that prolonged responses to vasodilatory substances (including prostaglandins (Tsuda et al 1983) and lactic acid), or absence of sympathetic nervous tone may have further contributed to hypotension. The importance of uncontrolled skeletal muscle vasodilatation in exercise‐induced hypotension is emphasized in recent studies in AP in which a fall in mean arterial pressure and a reduction in systemic vascular resistance after a 3 s bout of bicycle exercise appeared to be mediated by vasodilatation in exercising muscles (Wieling, Harms, ten Harkel, van Lieshout & Sprangers, 1996).…”