Venous occlusion plethysmography in patients with post-thrombotic venous claudication

Objective: Post-thrombotic venous claudication is a serious condition that may be treated with iliac vein stenting or open surgery, and there is a need for hemodynamic tests in the preoperative evaluation. The purpose of this study was to describe the results of venous occlusion plethysmography in patients with venous claudication and to analyze the outflow curve to find variables that best describe the functional abnormality in this patient group. Methods: Twenty-nine patients with previous deep venous thrombosis and with clinical evidence of venous claudication were retrospectively identified. The results of venous occlusion plethysmography in these patients were compared with results obtained in a group of 63 healthy control subjects of similar age and sex. Computerized strain-gauge plethysmography was used in a capacitance mode where the occlusion time is determined by an electronic detector allowing the maximal venous volume to be achieved in all limbs. Outflow volumes (OV1, OV4) and outflow fractions (OF1, OF4) were calculated at 1 and 4 seconds after cuff release. Outflow fraction is OV divided by maximal venous volume. Results: Both outflow volumes and outflow fractions were significantly reduced in patients compared with healthy control subjects. Outflow fractions were more sensitive than outflow volumes in identifying patients with venous claudication. The most discriminating variable was OF4 that was reduced below the normal lower limit in 69% of the patients, most severely reduced in patients with severe claudication. Conclusions: Patients with venous claudication attributable to remaining post-thrombotic iliofemoral obstructive disease are characterized by a functional disturbance shown with venous occlusion plethysmography as a reduced venous outflow during the initial 4 seconds following cuff release in relation to their true maximal venous volume. Our results suggest that venous occlusion plethysmography can be a valuable tool in the preoperative workup for selection of patients with iliofemoral vein obstruction that may benefit from venous intervention.