Venous hemodynamics in the legs of healthy human subjects and in primary varicose veins

Hemodynamic conditions in healthy human subjects as well as disturbed venou s hemodynamics in primary varicose veins ore discussed. The alterations of venous pressure in the deep and superficial veins occurring during the acti vation of the muscle venous pump of the calf are the driving power of the v enous circulation in the leg. The role of the ambulatory pressure gradient between the veins in the thigh and the lower leg is presented; the pressure gradient explains the existence of the private circulation according to Tr endelenburg as well as the findings of Bjordal that during calf muscle cont ractions the blood flows downward in the insufficient saphenous vein and in ward in the insufficient perforating veins of the lower leg. The pressure g radient could be the hemodynamic factor provoking venous reflux and trigger ing off the tendency to recurrence of varicose veins. Due to numerous commu nicating veins, the changes of venous pressure are transmitted immediately from deep into superficial veins of the lower leg; these veins act as conjo ined vessels. The hemodynamic disturbance in primary varicose veins is caus ed by the saphenous reflux, if large enough, the saphenous reflux may be re sponsible even for an advanced stage of chronic venous insufficiency. Based on a number of facts found in the literature it is stated that the insuffi cient calf perforating veins as well as the insufficiency of the femoral an d popliteal veins are not hemodynamically important as far as the deep vein s of the lower leg are sufficient.