Acute impact of intermittent pneumatic leg compression frequency on limb hemodynamics and vascular function in humans
Intermittent pneumatic leg compression (IPC) therapy is commonly used to treat symptoms associated with peripheral artery disease. However, the physiologic mechanism responsible for its effectiveness remains speculative. One hypothesis is that IPC increases shear stress during treatment and enhances endothelial cell (EC) function. In order to test this hypothesis we 1) characterized the hemodynamic profile in the treatment limb during IPC application and 2) used flow mediated dilation (FMD) and peak reactive hyperemia blood flow (RHBF) to assess alterations in EC function in response to single session of IPC. Eleven male subjects (age: 23.5 ± 4.7 years) underwent an hour of HF (2s inflation/3s deflation) and LF (4s inflation/16s deflation) IPC treatment on separate days. Doppler/ultrasonography of the popliteal artery was used to measure blood velocity and diameter at the 5th and 45th minute of treatment. FMD and RHBF were assessed pre and post treatment. IPC treatment had no effect on popliteal FMD (HF: pre: 2.45±.50%, post: 2.76 ±.32%; LF: pre: 3.16±.36%, post: 3.56±.52%) or RHBF. Cuff deflation elevated blood flow (BF) and shear rate (SR) and decreased oscillatory shear index (OSI) from baseline at the onset of both treatments (p<.01). This effect was lost by the 45th minute of HF treatment. When compared to baseline, both treatments significantly reduced BF and SR and increased OSI during cuff inflation (p<.01). In conclusion, a single session of IPC does not acutely impact popliteal FMD or RHBF despite significant alterations to the hemodynamic profile during treatment.^
Sean C. Newcomer, Purdue University.