VARIABILITY OF VENOUS HEMODYNAMICS WITH DAILY ACTIVITY

Purpose: This study was designed to evaluate changes in venous hemodyn amics that occur in normal, symptom-free male and female volunteers, a s a consequence of daily activity. Methods: Each leg of 25 symptom-fre e 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 f unction, and the noninvasive equivalent of ambulatory venous pressure. Results: There was significant change in venous valvular function (ve nous filling index) indicating progressive insufficiency in the late a fternoon 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 functi on and ambulatory venous pressures remained constant. Although there w ere significant leg volume and ejection volume differences at baseline in male volunteers compared with female volunteers, no gender differe nces were evident as a result of daily activity. five of 25 (20%) volu nteers and seven of 50 (14%) extremities had normal venous refill time s and venous function index in the morning, which became abnormal in t he afternoon, indicating deterioration of venous valve function. Concl usions: Venous hemodynamic changes occur normally as a consequence of daily activity and seem to result from valvular dysfunction. This occu rs in men and women and can alter diagnostic conclusions in 20% of oth erwise normal patients. These findings have important implications for venous testing and accurate patient evaluation. However, extrapolatio n of these data to patients with established venous disease should not be made.