Structured exercise improves calf muscle pump function in chronic venous insufficiency: a randomized trial.

Abstract

Deterioration of calf muscle pump function is associated with progression of chronic venous insufficiency (CVI). We postulated that a supervised exercise program would improve calf muscle strength and venous hemodynamics in patients with CVI. We recruited 31 patients for this randomized, prospective trial. Inclusion criteria required the presence of skin changes or ulceration (CEAP 4, 5, 6), and duplex ultrasound scanning (reflux or scarring) and air plethysmographic (APG) evidence of CVI. Subjects were randomized into control (n = 13) and therapy (n = 18) groups. Class II (30-40 mm Hg) compression hosiery was given to all. The experimental group received physical therapy designed specifically to strengthen calf musculature. Dynamic strength and power were measured with a Biodex II dynamometer (Biodex Medical Systems, Shirley, NY) at slow and fast speeds. Reflux (venous filling index) and calf pump function (ejection fraction, residual volume fraction) were measured with APG. Quality-of-life questionnaires and venous severity scores were also administered. Outcomes were compared 6 months after initiation of exercise. Probability of treatment effect was tested with univariate analysis of variance, with control for baseline values. Demographic variables and medical comorbidities were not different between groups. After 6 months of intervention, indicators of calf pump function returned to a normal range in the therapy (experimental) group. Mean residual volume fraction was improved in the exercise group (-8.75 +/- 4.6 vs 3.4 +/- 2.9 in the control group; P <.029). Mean ejection fraction was increased in the exercise group (3.48 +/- 2.7 vs -1.4 +/- 2.1 in the control group; P <.026). Reflux, while substantially greater than the normal value of 2.0 mL/s in both groups, was unchanged. The exercise regimen improved isokinetic peak torque/body weight at both slow speed (3.1 +/- 1.4 in the therapy group vs -1.0 +/- 1.1 in the control group; P <.05) and fast speed (2.8 +/- 0.9 in the therapy group vs - 0.3 +/- 0.6 in the control group; P <.03). No changes were observed in quality-of-life or severity scores. Calf muscle pump function and dynamic calf muscle strength were improved after a 6-month program of structured exercise. Directed physical conditioning of the calf musculature may prove beneficial for patients with or without alternative management options for severe CVI. Further research on exercise for patients with CVI is warranted.