Dose-response of compression therapy for chronic venous edema--higher pressures are associated with greater volume reduction: two randomized clinical studies.

BACKGROUND Two phase II clinical studies used an experimental, multi-chambered compression device with different cuff pressure combinations in subjects with leg edema and chronic venous insufficiency. The objective of each study was to evaluate the safety and the relative effects of different cuff pressure combinations to determine if edema reduction was dose-dependent. METHODS Each study enrolled adults with chronic (>or=6 weeks) venous edema corresponding to CEAP C(3)-C(5). The test device could apply different pressures at the foot, gaiter, mid-calf, and upper-calf. In the first study, the following six sustained pneumatic compression (SPC) profiles were applied for six hours each: 20, 30, and 40-mm Hg at the gaiter with graduated SPC (ie, lower pressures at the calf); and 20, 30, and 40-mm Hg at the gaiter with nongraduated SPC (ie, the same pressures at the calf). In the second study, the following three intermittent pneumatic compression (IPC) profiles were applied for two hours each: 40, 50, and 60-mm Hg at the gaiter with graduated IPC (ie, lower pressures at the calf). Each study included a baseline profile with no compression and two-day intervals between profiles. Leg volume was measured before and after compression using the water-displacement method. RESULTS A dose-response relationship was observed between increased SPC/IPC pressures and reduced limb edema. Limb volume was reduced most effectively with the highest pressures of 40-mm Hg nongraduated SPC and 60-mm Hg graduated IPC (136 mL and 87 mL, respectively); however, some subjects reported discomfort with these profiles. Limb volume was reduced by more than 100 mL with 30 to 40-mm Hg graduated SPC and by 69 mL with 50-mm Hg graduated IPC, and subjects rated these profiles as comfortable or very comfortable. Of the 28 study participants (12 SPC, 16 IPC), two subjects reported pain with 60-mm Hg IPC; no other adverse events were reported with SPC or IPC. CONCLUSION Pneumatic compression was safe and well-tolerated, with a dose-response relationship between increased SPC/IPC pressures and reduced leg edema. To our knowledge, this is the first study to demonstrate a dose-relationship in compression therapy: higher pressures are associated with greater volume reduction in subjects with chronic venous edema.