Noninvasive evaluation of venous function in chronic venous disease.

Measurements of calf volume changes during treadmill ambulation were taken using mercury-in-Silastic (silicone rubber) strain gauges for noninvasive study of venous function in patients with chronic venous disease. Seventy-four limbs were evaluated: 24 with postphlebitic changes, 26 with superficial varicosities, and 24 normal. Calf volume changes as measured by mercury-in-Silastic strain-gauge plethysmography (MISSGP) during ambulation correlated well (r = 0.8) with simultaneously obtained direct venous pressure measurements. The refill time as measured by MISSGP also correlated with the pressure restoration time (r = 0.8). Patients with moderate-to-severe obstructive patterns as shown by contrast venography were found to decrease their calf volume with MISSGP significantly less (P less than 0.001) than did those patients with minimal or no obstruction of venous outflow as depicted by venography. MISSGP is shown to be a useful method of quantitatively evaluating the efficiency of the calf venous pump, the degree of reflux, and the severity of venous obstruction.