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

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.