Assessment of venous flow and venous-valve function in lower extremity by ultrasound - determination of risk factor for venous disease -

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1 In lower extremities, venous flow and the effect of respiration and peritoneal pressure on it, and the role of venous valve were assessed. Ten lower extremities from 10 healthy volunteers were included in this study. In reverse-Trendelenburg position, veins of whole lower extremity were examined by ultrasound (US). Visualization rates of valves, venous flow and valve movement during normal respiration and those changing when peritoneal pressure increased were assessed. All valves in the whole lower extremities were satisfactorily visualized ; thus, venous flow and valve movement were easily assessed. Venous flow sympathized with respiration during normal respiration and no adverse flow at the site of the valves was observed even when peritoneal pressure increased. In conclusion, venous flow and valve movement in the whole lower extremity were satisfactorily assessed by ultrasound. The effect of respiration on the venous low and the role of the valves to prevent adverse flow were considered large.2 The relationship between venous-valve dysfunction and venous disease was assessed. Nine patients with deep venous thrombosis (DVT) and 6 patients with varicose veins (VV) were included in this study. All thrombi and varicose veins were confirmed by venograms. The methods used were similar to those adopted in the previous study. In all cases except 1 case of DVT, disappearance or shortening of valve was observed consistently (P<0.01 against normal control). Valve movement was always unclear. When peritoneal pressure increased, adverse flow lasting for more than 1 second was observed consistently (P<0.01), and area in a cross section of vein just below the valve increased remarkably in 3 of 6 cases of DVT (P=0.2) and 4 of 4 cases of VV (P=0.01). In conclusion, valve dysfunction should be associated with venous disease.3 According to these results, US is the first choice of examination for DVT/VV in our hospital and is also used frequently to assess post-operation DVT.