THE SIGNIFICANCE OF CALF MUSCLE PUMP FUNCTION IN VENOUS ULCERATION

Purpose: Patients with clinically evident chronic venous insufficiency were evaluated to relate the degree of insufficiency and calf muscle pump dysfunction to venous ulceration. Methods: Sixty-nine limbs in 55 patients with chronic venous insufficiency by Society for Vascular Surgery/International Society for Cardiovascular Surgery classification were compared in three groups: classes 1 and 2 with no history of ulceration (19 limbs); class 3 with healed ulceration (20 limbs); and class 3 with active ulcers (30 limbs). Air plethysmography measurements of outflow fraction, venous volume, venous filling time, venous filling index, ejection fi action, ejection volume, residual volume fraction, and residual volume were made. In 62 of the 69 limbs, color-flow duplex ultrasonography was used to determine the pattern of reflux. Results: The outflow fraction was normal in 84%, 75%, and 77% of nonulcerated, healed, and ulcerated limbs. The venous filling index was abnormal in most limbs (nonulcerated 95%, healed 90%, ulcerated 98%) but not significantly different among groups. Differences in calf muscle pump function were significant. Ulcerated limbs had significantly poorer ejection fractions (p = 0.0002) and greater residual volume fractions (p = 0.0006) than nonulcerated or healed limbs. By ultrasonography, deep and superficial vein incompetence was present in most limbs and was not statistically different among groups. Although venous insufficiency was not measurably different among groups, limbs with active venous ulcers had significantly poorer calf muscle pump function than those with healed ulcers or with no history of ulceration. Conclusion: Venous insufficiency is necessary but not sufficient to cause ulceration, and a deficiency of the calf muscle pump is significant to the severity of venous ulceration.