Effects of reactive hyperemia and nifedipine on forearm vascular resistance in essential hypertension: evidence for functional abnormality.
The aim of this study was to explore whether the increased forearm vascular resistance in patients with essential hypertension is predominantly due to structural or functional changes. We studied 22 male patients with moderate essential hypertension and 22 age- and weight-matched normotensive men (28-52 years). The effects of intraarterially infused nifedipine, reactive hyperemia after 10 min arterial occlusion combined with handgrip exercise and local heating, and arterial occlusion combined with nifedipine on forearm blood flow and blood pressure were investigated in random order. Blood pressure was measured directly in the brachial artery and forearm blood flow by venous occlusion plethysmography. The calculated resistance values reduced by nifedipine or following arterial occlusion remained significantly higher in hypertensives than in normotensives. However, the maximal vasodilation achieved by the combination of arterial occlusion and nifedipine resulted in a similar decrease of resistance in hypertensives and normotensives. These data suggest that there is an important functional component of the elevated vascular resistance in patients with essential hypertension.
Schulte
K L
KL
Department of Internal Medicine, Klinikum Steglitz, Freie Universität Berlin, F.R.G.
Braun
J
J
Meyer-Sabellek
W
W
Gotzen
R
R
Distler
A
A
D000328:Adult; D001783:Blood Flow Velocity; D001794:Blood Pressure; D005542:Forearm / Q000098:blood supply; D006801:Humans; D006940:Hyperemia / Q000503:physiopathology*; D006973:Hypertension / Q000503:physiopathology*; D007511:Ischemia / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D009543:Nifedipine / Q000494:pharmacology*; D014655:Vascular Resistance / Q000187:drug effects
D009543:Nifedipine