Tarnay TJ, Rohr PR, Davidson AG, Stevenson MM, Byars EF, Hopkins GR.
Pneumatic calf compression, fibrinolysis, and the prevention of deep venous
thrombosis.
Surgery 1980 Oct;88(4):489-96

In a previous pilot study that did not reach statistical significance,
intermittent single-leg pneumatic compression appeared effective in reducing the
incidence of calf vein thrombosis not only in the pumped calf but also in the
unpumped leg in 37 patients, using the 125I-fibrinogen (Abbott Laboratories)
technique. The present study was undertaken to investigate mechanical induction
of local and systemic fibrinolysis. The euglobulin lysis time in the arm venous
effluent was determined in five volunteers before and after unilateral arm
compression for 1/2 hour. Shortening averaged 19% (not significant). The
experiment was repeated using bilateral calf-length boots with femoral vein
sampling. Euglobulin lysis decreased 22% (P < 0.001). To uncover possible
systemic effects, the protocol was altered using calf boots with sampling from
the arm. The euglobulin lysis diminished 6% in 57 volunteers (P < 0.001). In 27
others the effects of thigh-length and calf-length boots were compared. In half,
pumping with a short boot was undertaken first, and in the remainder, the long
boot was applied initially. One-half hour of pumping was followed by 1/2 hour of
rest. Immediately afterward the second period of pumping took place and continued
for 1/2 hour. A total of four arm vein samples were obtained, one before and
after each pumping period. Although, in retrospect, the 1/2-hour rest period was
inadequate to permit the subjects to return to basal conditions, statistically
significant decreases in euglobin lysis time (P = 0.05) occurred with the long
boots. This study shows intermittent calf compression increases fibrinolytic
potential locally and this effect can be demonstrated systemically. The greater
the volume of tissue compressed, the greater the response. The efficacy of
intermittent venous compression in reducing the incidence of deep venous
thrombosis may be due, in part, to localized induction of fibrinolysis.