Calf Pump Activity Influencing Venous Hemodynamics in the Lower Extremity

Abstract

Although flow in the arterial system constitutes essentially an uncomplicated pulsing streaming in one direction from the heart to the periphery, venous return from the lower extremity to the heart in upright position is directed against the gravitation force and displays a more complex pattern; this field of the venous circulation and pathophysiology continues to be an insufficiently understood sphere with controversial perceptions concerning pressure and flow interactions in three different parts of venous circulation in the lower extremity: in deep and superficial veins, and in communicating channels between them. Moreover, several hemodynamic phenomena of the venous circulation have not so far been unequivocally apprehended or precisely defined, which provides for misunderstanding and misinterpretations, and deforms results presented after surgical and nonsurgical treatment of varicose veins.In this article, proven evidences pertaining to the influence of calf pump activity on pressure and flow changes that affect venous return to the heart were gathered from the references. Special point of view was concentrated on the hemodynamic significance of ambulatory venous hypertension, and on confusing opinions concerning incompetent calf perforators and reflux recurrence. Effect of the Hydrostatic PressureDuring quiet standing with relaxed calf muscles, gravitation force induces hydrostatic hypertension in the veins of the Keywords ► venous hemodynamics ► calf perforators ► venous hypertension ► hemodynamic paradox AbstractCalf 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 t...

Manual Lymphatic Drainage in the Treatment of Chronic Venous Disease

“…During muscle contractions, the venous blood is forced in direction to the heart and the valves prevent reflux during relaxation [27,48,76]. As deep veins are tethered to surrounding tissues, muscle relaxation causes the veins to open, lead to a sudden drop in pressure within these vessels [58,77,78].…”

Studying the in vivo microcirculatory adaptation to isometric contraction (dorsiflexion) in the human lower limb

“…Laser Doppler flowmetry (LDF) and photoplethismography (PPG) have gained relevance as practical tools to assess microcirculation physiology [1][2] . These technologies, based in related biophysical principles, are simple to use, cause minimal discomfort, and provide assessments close to the normal local perfusion conditions.…”

“…A fluxometria por laser Doppler e a fotopletismografia ganharam relevância como ferramentas práticas para avaliar a fisiologia da microcirculação [1][2] . Estas tecnologias, baseadas em princípios biofísicos relacionados, são de simples utilização, causando um desconforto mínimo e permitem avaliações próximas das condições normais de perfusão local.…”

Changes in the Volume and Circumference of the Torso, Leg and Arm after Cycling in the Heat Determined Using 3D Whole Body Scanners

“…We hypothesized that the relative volume of the torso would decrease more than that of the arms and legs after exercise since the highest sweat rates are observed in the torso region [8]. Also, we hypothesized that the volume of the legs would decrease more than that of the arms since venous and lymphatic flow back to the body is enhanced by the muscle pump [11,12]. Moreover, Ayling found no evidence of increased evaporation in the leg while cycling even though the skin temperature of the legs is higher and the airflow around the skin of the legs in increased due to the cycling movement [13].…”