Hemodynamic evaluation of foot venous compression devices.

Purpose: Venous compression devices effectively prevent deep venous thrombosis. Recently, because traumatic injury of the limb often precludes application of calf devices, newer methods have been developed that are only applied to the foot. This study was designed to evaluate the venous hemodynamic effects produced by four different compressive devices compared with calf-only intermittent pneumatic compression (IPC).

Methods: Twenty-seven healthy volunteers had application of each device followed by duplex scanning determination of the venous hemodynamics at the popliteal vein (PV) and the common femoral vein (CFV). Endpoints included (1) resting (peak) systolic velocity (RSV); (2) maximum venous velocity (MVV) during device activation; (3) acceleration, the slope of the line from RSV to MVV; and (4) return time (RT) from MVV back to RSV. The devices evaluated included two commercially available mechanical foot devices, (1) foot compressive device (FCD1), and (2) FCD2; (3) an experimental mechanical foot device (FCD3); (4) an experimental pneumatic foot device (FCD4); and (5) a calf-only IPC device (IPC).

Results: The RSV was higher in the CFV than the PV. The initial RSV was not statistically significant between the five experimental groups (p = 0.37) at either the PV or CFV, although the RSV was higher in the CFV than in the calf (CFV, 24.3 +/- 6.7 cm/sec; PV, 12.5 +/- 3.7 cm/sec; p < 0.0001). MVV was significantly higher with FCD2 and the IPC (p = 0.0002) at the PV level, but this difference decreased at the CFV. Acceleration was greatest with the two available foot devices, FCD1 and FCD2, compared with the other three devices (p < 0.0001) at both levels. On the other hand, the RT was significantly longer only with the IPC; RT was four to 10 times slower at the PV and three to five times slower at the CFV compared with the other four devices.

Conclusions: The two commercially available foot devices, FCD1 and FCD2, and the IPC produced significant alterations in venous hemodynamics. Changes produced at the PV level by both foot and calf devices were seen proximally at the CFV, although the changes were usually less. The mechanical devices produced rapid acceleration of venous flow to an elevated MVV, whereas the IPC produced an elevated peak with a sustained period of flow above baseline (RT). Further clinical comparison should be completed before widespread adaptation of these devices as an equivalent to existing IPC devices.