In Vivo Compliance of the Human Saphenous Vein Measured by Sonography: Comparison with Plethysmographic and in vitro Measurements

Abstract

Objective: To evaluate a non-invasive and selective measurement of in vivo venous compliance of the human saphenous vein using sonography. Design: An experimental study in patients prior to coronary bypass surgery. Setting: Departments of Physiology and Cardiothoracic Surgery, University Hospital of Angers. Patients: Thirty patients investigated prior to coronary bypass surgery. Interventions: Simultaneous strain-gauge venous occlusion plethysmography (VOP) and measurements of the circumference of the great saphenous vein by sonography at four different occlusion pressures: 20, 30, 40 and 50 mmHg. In 10 of the same patients, in vitro determination of pressure–volume relationship during progressive inflation of excised saphenous vein samples. Main outcome measures: Venous compliance obtained with the three methods. Results: Weak correlation coefficients were found between in vitro measurements and VOP ( r=0.478, p<0.01) and sonography ( r=0.497, p<0.02). Although individual correlations between in vitro and VOP measurements ranged from 0.928 to 0.999, a wide heterogeneity was found with sonography (from 0.620 to 0.985). Conclusions: Sonography allows the selective measurement of in vivo venous compliance, although the measured compliances differ from other techniques.