Diminished finger volume pulse in borderline hypertension: evidence for early structural vascular abnormality.

Digital volume pulse maximum dilation was determined in 27 patients with borderline essential hypertension (BHT) and 28 age-matched normotensive controls (NT). Finger pulse volume (PV) and finger systolic pressure (SBP) were measured by pneumoplethysmography during vasodilation induced by combining direct and reflex heat dilation and reactive hyperemia. Finger SBP was higher (p less than 0.01) in BHT than in NT (120 +/- 18.7 vs. 104 +/- 14.8 mm Hg, respectively); PV was lower (p less than 0.01) in BHT than in NT (9.7 +/- 4.2 vs. 15.3 +/- 6 ml/5 ml finger X 10(-3). Pulse volume correlated inversely with SBP in BHT (r = -0.40, p less than 0.05) but was unrelated to SBP in NT. Pulse volume was not altered by high or low sodium intake in BHT or NT despite significant changes in plasma renin activity (PRA). In BHT finger vessels are less distensible at a higher pressure than in NT. This abnormality is demonstrable during maneuvers to withdraw sympathetic tone and is not influenced by alteration of PRA. These data support the concept that BHT can produce structural vascular change, and demonstrate that this abnormality can be detected by a relatively simple method.