Compliance Changes in Venous Insufficiency

In 37 patients (69 limbs) referred to Mayo Clinic's Vascular Center for possible venous valvular insufficiency in the lower limb, calf muscle pump function, calf compliance, and venous refilling times were measured by strain gauge plethysmography techniques. Patient limbs were separated into four categories based on 90% refilling time (T₉₀) following fifteen deep knee bends: Normal (n =16), mild/moderate (n = 28), severe (n = 16), and edema of nonvenous origin (n=9). Pump function was assessed in actual pumping volumes (mL) and in percent pumping volumes (mL/100 mL), and was reduced in all noncontrol categories. Calf compliance was assessed in actual volume change (mL/mmHg) and in percent volume change (mL/100 mL/mmHg) and was increased in the severe reflux category. Ten study patients had 1 normal category limb and 1 reflux category limb. Paired analysis of these limbs showed pump function to be decreased and calf compliance to be increased in the diseased group limbs.