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 Su rgery/International Society for Cardiovascular Surgery classification were compared in three groups: classes 1 and 2 with no history of ulce ration (19 limbs); class 3 with healed ulceration (20 limbs); and clas s 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 duple x 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 i n most limbs (nonulcerated 95%, healed 90%, ulcerated 98%) but not sig nificantly different among groups. Differences in calf muscle pump fun ction were significant. Ulcerated limbs had significantly poorer eject ion fractions (p = 0.0002) and greater residual volume fractions (p = 0.0006) than nonulcerated or healed limbs. By ultrasonography, deep an d superficial vein incompetence was present in most limbs and was not statistically different among groups. Although venous insufficiency wa s not measurably different among groups, limbs with active venous ulce rs had significantly poorer calf muscle pump function than those with healed ulcers or with no history of ulceration. Conclusion: Venous ins ufficiency is necessary but not sufficient to cause ulceration, and a deficiency of the calf muscle pump is significant to the severity of v enous ulceration.