Forearm arterial compliance: the validation of a plethysmographic technique for the measurement of arterial compliance.

Arterial compliance was determined in eight normal subjects and 23 patients with hypertension and vascular disease by two independent techniques: (a) with a plethysmographic strain gauge (to measure pulsatile forearm volume changes as representing intra-arterial volume changes) and an automated sphygmomanometric system (to measure pulse pressure) and (b) calculation from the local pulse wave velocity and dimension of the brachial artery measured by pulsed wave Doppler ultrasound. Arterial compliance measured both by the plethysmographic technique and calculated from the pulse wave velocity was reduced in subjects with hypertension and vascular disease as compared with normal subjects. The regression equation between the compliance determined by the plethysmographic technique (x) and that calculated (y) from the pulse wave velocity and brachial arterial diameter was y = 3. 35x + 1.53, r = 0.77, P less than 0.001. The good correlation appears to validate the plethysmographic technique as a method of determining arterial compliance.