VARIABILITY OF VENOUS HEMODYNAMICS WITH DAILY ACTIVITY

Purpose: This study was designed to evaluate changes in venous hemodynamics that occur in normal, symptom-free male and female volunteers, as a consequence of daily activity. Methods: Each leg of 25 symptom-free volunteers was prospectively studied twice in the early morning and twice in the late afternoon on 2 days. Air plethysmography was used to evaluate venous volumes, venous valvular function, calf muscle pump function, and the noninvasive equivalent of ambulatory venous pressure. Results: There was significant change in venous valvular function (venous filling index) indicating progressive insufficiency in the late afternoon compared with the results of the morning studies (p = 0.039). This was demonstrated by a shortened venous filling time (p = 0.033) but not a change in venous volume (P = 0.794). Calf muscle pump function and ambulatory venous pressures remained constant. Although there were significant leg volume and ejection volume differences at baseline in male volunteers compared with female volunteers, no gender differences were evident as a result of daily activity. five of 25 (20%) volunteers and seven of 50 (14%) extremities had normal venous refill times and venous function index in the morning, which became abnormal in the afternoon, indicating deterioration of venous valve function. Conclusions: Venous hemodynamic changes occur normally as a consequence of daily activity and seem to result from valvular dysfunction. This occurs in men and women and can alter diagnostic conclusions in 20% of otherwise normal patients. These findings have important implications for venous testing and accurate patient evaluation. However, extrapolation of these data to patients with established venous disease should not be made.