Ambulatory venous hypertension : Component analysis in 373 limbs. Discussion

Purpose: We studied factors contributing to ambulatory venous hypertension in patients with symptoms of chronic venous insufficiency in order to delineate the contribution of each to global venous hypertension. Methods: A total of 373 consecutive limbs with ambulatory venous hypertension were studied. Simultaneous ambulatory venous pressure and air plethysmography measurements allowed compliance calculations. With reactive hyperemia, maximal arterial inflow was measured. Air plethysmography provided calf venous pump capacitance and ejection fraction data. Reflux was quantified by a point system based on Duplex, venous filling index on airplethysmography (VFI-90), Valsalva foot venous pressure, and ambulatory venous pressure recovery time (VFT). Multiple regression analysis was used to model ambulatory venous pressure in terms of these variables. Results: Six major causes of ambulatory venous hypertension were identified and quantified : 1. reflux, 2. increased arterial inflow, 3. reduced venous capacitance, 4. poor ejection fraction, 5. poor compliance of the calf venous pump, and 6. a combination of factors. Of the total, 91% of the limbs had at least two of these factors, 57% had three factors, and 24% had four factors contributing to ambulatory venous hypertension. Reflux was present in 97% of limbs but was significant (VFT <15 seconds) in only 57%, suggesting that other factors were dominant in the remainder. (continued on next page) Conclusion: Ambulatory venous hypertension is a multifactorial entity. Many of the contributing factors are interrelated in a complex fashion. Regression analysis indicates that even though reflux followed by arterial inflow and capacitance were important as single contributing factors, a combination of factors is more important than any single individual factor in the genesis of ambulatory venous hypertension. VFT was found to be superior to other measurements in quantifying global reflux.