Abstract
Calf muscle pump is the motive force enhancing return of venous blood from the lower
extremity to the heart. It causes displacement of venous blood in both vertical and
horizontal directions, generates ambulatory pressure gradient between thigh and lower
leg veins, and bidirectional streaming within calf perforators. Ambulatory pressure
gradient triggers venous reflux in incompetent veins, which induces ambulatory venous
hypertension in the lower leg and foot. Bidirectional flow in calf perforators enables
quick pressure equalization between deep and superficial veins of the lower leg; the
outward (into the superficial veins) oriented component of the bidirectional flow
taking place during calf muscle contraction is no pathological reflux but a physiological
centripetal flow streaming via great saphenous vein into the femoral vein. Calf perforators
are communicating channels between both systems making them conjoined vessels; they
are not involved in the generation of pathological hemodynamic situations, nor do
they cause ambulatory venous hypertension. The real cause why recurrences develop
has not as yet been cleared. Pressure gradient arising during calf pump activity between
the femoral vein and the saphenous remnant after abolition of saphenous reflux triggers
biophysical and biochemical events, which might induce recurrence. Thus, abolition
of saphenous reflux removes the hemodynamic disturbance, but at the same time it generates
precondition for reflux recurrence and for the comeback of the previous pathological
situation; this chain of events has been called hemodynamic paradox.
Keywords
venous hemodynamics - calf perforators - venous hypertension - hemodynamic paradox
