The role of deep venous valvular function in lower extremity venous drainage

BACKGROUND: The aim of this study was to assess the role of deep venous valvular function in lower extremity venous drainage.METHODS: The study involved 22 volunteers without venous pathology. Duplex ultrasound scanning (DUS) was performed in all subjects to assess venous diameter, venous lumen reduction, and valve cycle in superficial femoral vein. Six subjects underwent DUS with ECG synchronization.RESULTS: Active function of valves was recorded in 9 patients with a venous lumen reduction of 46.9%. Active function of valves was not registered in 7 subjects, while the degree of venous lumen reduction was 45.9%. There was no statistical difference between the subjects (P>0.05). Valve cycles were associated with the act of breathing, i.e. “vis a fronte” factor. At 3 days active valvular function was recorded in all patients who received intravenous infusion therapy, and was strongly associated with breathing. To exclude the “vis a fronte” effects, the patients were asked to hold their breath: the valves closed strictly after the ventricular systole. However, we regard this not as an influence of the kinetic energy of blood movement during cardiac output, but a potential energy of the deformation of the vascular wall. Such mechanism of the venous outflow may be described as an arterio-venous pump.CONCLUSIONS: Continuous work of the deep venous valves is not a prerequisite for venous outflow from the lower extremities. Active function of the valves is associated with a mechanical factor i.e. the volume of blood accumulated in the venous system.