Ambulatory venous pressure revisited

Purpose: The purpose of this study was to describe a method for measuring t he deep venous pressure changes in the lower extremity and compare it with those obtained in the dorsal foot vein. Methods: After cannulation of the posterior tibial vein, a catheter with a pressure transducer in its tip was inserted and placed at the knee joint le vel. The dorsal foot vein was also cannulated. Pressures were recorded simu ltaneously at both sites during toe stands and repeated with the probe in t he upper, middle, and tower calf. Results: The study was performed in 45 patients with signs and symptoms of chronic venous insufficiency. Duplex Doppler scanning and ascending and des cending venography performed before pressure measurements revealed saphenou s vein incompetence in 11 lower extremities, incompetent perforators in 11 extremities (eight were combined with saphenous incompetence), and marked c ompression of popliteal vein with plantar flexion in 28 extremities. No sig nificant deep axial reflux was observed on duplex Doppler examination or de scending venography. No morphologic outflow obstruction was detected. The m ean deep pressure at the knee joint level fell during toe stands, -15K +/- 27 (SD), and the mean dorsal foot vein pressure drop was even more marked, -75% +/- 22 (SD). Although the exercise pressure in the dorsal foot vein de creased in all patients (range, 13-90% drop), the popliteal vein pressure i ncreased (4-72%) in nine limbs, decreased only marginally if at all in 15 l imbs (0-15%), and fell more markedly in 21 extremities (22-65%). Deep vein recovery time was considerably shorter overall as compared with the finding s by the dorsal vein measurement. In the comparison of limbs with and witho ut superficial reflux the recovery times in the deep system were significan tly shorter in limbs with superficial incompetence. Conclusion: Ambulatory dorsal foot venous pressure is not always accurate i n detecting changes in the pressure of the tibial and popliteal veins. Alth ough dorsal foot venous pressure may be normal, deep venous pressure may de crease to a lesser degree or even increase.