Abstract 6054: Immersing Feet in CO 2 -Rich Water-Bath Improves Ulcer Healing on Ischemic Limb after Infrainguinal Bypass Surgery

Abstract

Background : We have shown that immersion of feet in warmed water enriched with carbon dioxide (CO 2 immersion) improves subcutaneous microcirculation in critical limb ischemia (CLI) with ischemic ulcer/gangrene. Using an animal model, other group has reported that the CO 2 immersion enhances collateral blood flow in ischemic limb via mobilization of endothelial progenitor cells and activation of NO-cGMP system. For CLI patients with ulcer/gangrene, infrainguinal bypass surgery is the standard therapy. However, ulcer healing and prevention of amputation still remain suboptimal. In order to know whether the CO 2 immersion improves the clinical efficacy, here we performed the CO 2 immersion after infrainguinal bypass surgery. Methods : This study was designed as a prospective controlled trial. Fifty-five patients with ischemic ulcer/gangrene underwent the standard care including successful infrainguinal bypass surgery were enrolled and were randomly divided into the two groups; patients underwent standard care added CO 2 immersion (CO 2 group, 27 patients with 30 limbs) and patients received standard care alone (control group, 28 patients with 30 limbs). The patients in the CO 2 group immersed their feet in CO 2 enriched water (depth of 20 –30 cm, 37–38°C, duration for 10 minutes) twice a day. Primary endpoint was defined as complete healing of ischemic ulcers. Results : Baseline demographical data, traditional risk factors, surgical procedure, ankle pressure and transcutaneous oxygen pressure (tcPO 2 ) were comparable between the two groups. Rate of the complete ulcer healing after 1-year was much higher in the CO 2 group than in the control group (43.3% vs. 20.0%, HR 2.72, 95%CI 1.03–7.17, p=0.043). Cox multivariate analysis revealed that CO 2 immersion (HR 4.13, 95%CI 1.09 –15.75, p=0.038), diabetes (HR 0.020, 95%CI 0.01–.303, p=0.005) and tcPO 2 (HR 1.04, 95%CI 1.00 –1.09, p=0.050) were independent predictors for complete ulcer healing. In contrast, rates of 1-year mortality, graft patency and limbs salvage showed no significant differences between 2 groups (p=0.55, p=0.47 and p=0.16, respectively). Conclusion : The CO 2 immersion after infrainguinal bypass surgery provided additional benefit for the ulcer healing in CLI patients with ulcer/gangrene.