Computerized Venous Strain-gauge Plethysmography is a Reliable Method for Measuring Venous Function

Abstract

To achieve reference values for computerized strain-gauge plethysmography (SGP), to assess reproducibility, and to evaluate the influence of different factors such as age, gender, body mass index, and symptomatic post-thrombotic disease on commonly used variables. Sixty-three healthy controls and 56 patients with previous deep venous thrombosis (DVT) were included. All participants underwent computerized SGP with evaluation of outflow capacity, as well as evaluation of venous reflux and muscle pump function. All variables were significantly reduced in DVT limbs, both compared with contralateral limbs and with healthy controls. Only two patients had all values within normal ranges (=mean±2 SD in controls). Measures of outflow capacity had a coefficient of variation (CV) of 5-6% and exercise-induced volume changes a CV of 10-15%. In symptomatic post-thrombotic limbs half-refilling time was significantly related to presence of edema (R=-0.28, p<.05) and to chronic skin changes (R=-0.58, p<.001). We suggest that our values in healthy controls can be used as new reference values for computerized venous strain-gauge plethysmography. The computerized design ensures high reproducibility and the results indicate that this is a very useful and sensitive test for functional quantitative assessment of patients with venous disease.