POSTPRANDIAL HYPOTENSION - HEMODYNAMIC DIFFERENCES BETWEEN MULTIPLE SYSTEM ATROPHY AND PERIPHERAL AUTONOMIC NEUROPATHY

To clarify the mechanism of postprandial hypotension (PPH), we perform ed hemodynamic investigation after oral glucose ingestion in ten patie nts with multiple system atrophy (MSA), three patients with peripheral autonomic neuropathy (PN) and 16 normal controls. Blood pressure (BP) and heart rate (HR) were measured with an automatic sphygmomanometer; cardiac out (CO) and lower leg blood flow (LBF) with impedance plethy smography; and portal blood flow (PBF) using a B-mode pulse Doppler. I n normal subjects, BP, LBF and vascular resistance of the lower leg (L VR) were not changed, but HR slightly increased, and PBF and CO signif icantly increased after oral ingestion of 75 g glucose. In the patient s with MSA, BP fell significantly 15 min after glucose ingestion, and HR and CO did not increase. PBF and LBF increased and LVR fell signifi cantly. In PN patients, BP decreased at 15 min after glucose ingestion , but soon recovered. Increase of PBF and decrease of LVR in them were almost similar to those in the MSA group, and increase of CO was grea ter than that in the controls. These results suggest that both systemi c vasodilatation (presumably due to gastrointestinal vasodilatatory pe ptides) and lack of compensatory increase of CO and LVR play important roles in PPH.