Venous reflux has a limited effect on calf muscle pump dysfunction in post-thrombotic patients

Abstract

The purpose of the present study was to evaluate the relationship between calf muscle pump dysfunction (CMD) and the presence and location of valvular incompetence. Deep vein obstruction might influence CMD, and so venous outflow resistance (VOR) was measured. VOR and calf muscle pump function were measured in 81 patients, 7-13 years after venographically confirmed lower-extremity deep venous thrombosis. The supine venous pump function test (SVPT) measures CMD, and the VOR measures the presence of venous outflow obstructions, both with the use of strain-gauge plethysmography. Valvular incompetence was measured using duplex scanning in 16 vein segments of one leg. Venous reflux was measured in proximal veins using the Valsalva manoeuvre, and in the distal veins by distal manual compression with sudden release. Abnormal proximal venous reflux was defined as a reflux time of more than 1 s, and abnormal distal venous reflux as a reflux time of more than 0.5 s. No statistically significant relationship was found between the SVPT and either the location or the number of vein segments with reflux. Of the 81 patients, only nine still had an abnormally high VOR, and this VOR showed no relationship with the SVPT. In conclusion, venous reflux has a limited effect on CMD, as measured by the SVPT. The presence of a venous outflow obstruction did not significantly influence the SVPT. Duplex scanning and the SVPT are independent complementary tests for evaluating chronic venous insufficiency.

Chronic venous insufficiency in post-thrombotic patients

“…It has been unclear how much these different mechanisms are interdependent. In this issue of Clinical Science, Haenen and co-workers [6] examined the relationship between venous reflux, measured by duplex ultrasound, calf muscle pump function, measured by the supine venous pump function test (SVPT), and obstruction to venous outflow, measured by venous outflow resistance, in patients up to 13 years after lower limb DVT. They found that there was no relationship between the location and extent of venous reflux and calf muscle pump efficacy, although there was a tendency for calf muscle pump function to be impaired in those patients with the most widespread reflux.…”

“…In the presence of varicose veins there is increased venous compliance [19] and reduced ejection of calf venous volume [20]. As yet undefined, and not discussed in the report by Haenen et al [6], is whether some of the changes observed in calf muscle pump function in the setting of varicose veins may actually be consequent on a primary varicose vein disorder rather than secondary to past DVT. Furthermore, although the current study indicates that calf muscle pump dysfunction is an independent risk factor for the development of chronic venous insufficiency after DVT [6], it must be borne in mind that there is a secondary interaction that occurs whereby chronic venous insufficiency changes themselves reduce the range of movement of the ankle and thus the function of the calf muscle pump [7].…”