EFFECTS OF INTERMITTENT PNEUMATIC COMPRESSION ON VENOUS HEMODYNAMICS AND FIBRINOLYTIC-ACTIVITY

Pneumatic intermittent compression is an effective method to prevent p ostoperative venous thromboembolism. Its efficacy has been ascribed to both a haemodynamic action (increase of blood flow velocity) and a st imulation of endogenous fibrinolytic activity [via the production of t issue-type plasminogen activator (t-PA) by the vascular endothelium]. The relative contribution of these two effects is still debated. In a randomized, cross-over study in ten healthy volunteers, we compared th e haemodynamic and fibrinolytic effects of two different pneumatic int ermittent compression devices: a classical, low-pressure, whole-leg bo ots system, and a novel, high-pressure, plantar compression system. Th e study was performed at rest, to compare haemodynamics and fibrinolyt ic activity modifications, and under induced venous leg stasis, in ord er to compare the two compression systems in experimental conditions m imicking laparoscopic surgery. Our data show that (1) a pneumatic comp ression device that exerts its compression on the plantar venous plexu s only induced an increase of venous blood peak velocity and flow in t he common femoral vein that is very similar to that induced by the cla ssical whole-leg boots compression system; (2) the venous stasis induc ed by an external pressure mimicking the conditions of laparoscopic su rgery further increased the absolute velocity and flow increase, with the two intermittent compression systems tested; (3) no changes of t-P A or plasminogen activator-inhibitor: 1 antigens were observed with ei ther pneumatic compression device. In conclusion, the present study in dicates that the antithrombotic effect of mechanical prophylaxis is pr obably mainly due to its ability to increase venous peak velocity and flow, especially under venous stasis conditions.