The hemodynamic significance of the calf perforating veins continues to be the point of controversy. The conception that incompetent perforating veins cause hemodynamic disturbance and are responsible for the formation of leg ulceration has still many adherents prefering perforator surgery, whereas others reject any causal relation between large, incompetent perforators and severe forms of chronic venous insufficiency. In this study well documented facts concerning the impact of the calf perforators on the venous hemodynamics are reviewed. There is a bidirectional flow within calf perforators in healthy subjects enabling a quick equilibration of pressure changes produced during calf muscle contractions and relaxations, so that recordings of the mean pressure display identical values in superficial and deep veins of the lower leg, a feature typical of conjoined vessels. In cases with saphenous reflux, the bidirectional flow within calf perforators has a distinct inward vector directed to the deep veins; this inward component is the more pronounced, the larger the saphenous reflux is. Incompetent calf perforators do not cause ambulatory venous hypertension, exactly the opposite happens: the high hydrostatic pressure found in the quiet standing position drops significantly during ambulation, as soon as the saphenous reflux is interrupted. In primary varicose veins calf perforators can not become the source of reflux because they are situated at the lower pole of the ambulatory pressure gradient, which occurs between thigh and lower leg veins during ambulation. The size of the calf perforators is determined by the amount of saphenous reflux. When the saphenous reflux is abolished (e.g. by high ligation), the enlarged calf perforators diminish.

Division of Vascular Surgery Department of Surgery University Hospital Hradec Kralove Czech Republic