Severity and location of venous valvular insufficiency: the importance of distal valve function.

Venous calf pump function was evaluated with special reference to distribution and severity of deep venous reflux at different levels. A combination of ultrasonography, foot volumetry and venous plethysmography was used in 100 consecutive patients, 32 of whom were also studied with phlebography and intravenous pressure measurements. A clear relationship was found between clinical stage of chronic venous insufficiency and number of segments with reflux. Clinically important deep venous insufficiency was found particularly in patients with reflux in the distal posterior tibial veins, even in the presence of competent popliteal valves. The results demonstrated the calf pump to be functionally divided into a series of pumps, with the distal part more important than the proximal. The importance of evaluating venous valvular function at different levels for adequate assessment of venous calf pump function is emphasized.