The role of air plethysmography in monitoring results of venous surgery

Abstract

The development of an objective, noninvasive method to assess the hemodynamic effects of venous surgery has long been awaited. Previous methods used to evaluate the results of surgery for varicose veins and venous stasis ulceration have been limited in their quantitative assessment. Now, by use of air plethysmography (APG), we can accurately quantify the effectiveness of corrective venous surgery. Twenty-five extremities that had evidence of venous insufficiency were examined with use of APG before and after venous surgical procedures. Surgery was directed at specific sites of venous incompetence as defined by physical examination and high-resolution duplex imaging. Twenty-one extremities underwent ligation and stripping of the greater saphenous vein. In these patients, APG showed an improvement in venous reflux as demonstrated by a decrease in the venous filling index from 6.6 ± 0.7 ml/sec to 1.8 ± 0.3 ml/sec (p = 0.0001) and venous volume from 177.1 ± 14.5 ml to 139.2 ± 8.9 ml (p = 0.0008). In addition, these patients showed a mild improvement in calf muscle pump function as noted by an improvement in ejection fraction from 45.8% ± 2.0% to 50.8% ± 2.5% (p = 0.07). The residual volume fraction decreased from 45.0% ± 3.4% to 42.0% ± 3.7%, a difference that was not statistically significant (p = 0.4). Four extremities with grade III chronic venous insufficiency underwent popliteal vein valve transplantation with use of an autogenous axillary vein valve. Venous reflux in these patients was reduced dramatically in the early postoperative period, with the venous filling index dropping from 14.2 ± 2.3 ml/sec before the operation to 5.1 ± 1.4 ml/sec after the operation (p = 0.08) in conjunction with a drop in venous volume from 190.9 ± 35.4 ml to 135.2 ± 10.7 ml (p = 0.15). APG offers a unique and quantitative technique to evaluate the results of reconstructive venous surgery. It is simple and noninvasive, and we believe it represents an improvement on older methods for evaluating the effect of surgery on the venous hemodynamics of the leg.