Evaluation of the treatment volume and removal rate of Rheocarna: A novel adsorption‐type blood purification device for patients with chronic limb‐threatening ischemia

Introduction Chronic limb‐threatening ischemia (CLTI) is a clinical syndrome defined by peripheral arterial disease (PAD) combined with rest pain, gangrene, or leg ulceration for longer than two weeks resulting in lower extremity amputation. In recent years, low‐density lipoprotein apheresis (LDL‐A) has been implemented for PAD treatment. However, it has not been possible to ensure insurance coverage for patients with lower LDL levels than 140 mg/dL under cholesterol‐lowering drugs. Rheocarna is a novel adsorption‐type blood purification device for the treatment of CLTI by adsorbing LDL and fibrinogen (Fib) that is not constrained by hypercholesterolemia and is not amenable to or nonresponsive to revascularization surgery. The only requirements for use are that the blood flow rate increases up to 200 mL/min gradually. Methods To evaluate the applicability of this treatment procedure, we compared the removal rates of Fib and LDL following Rheocarna therapy using various blood treatment volumes (6, 10.5, and 19.5 L). Results Fib and LDL removal rates were about 20% and 15%–25% per treatment, with no significant differences between treatment volumes. Following treatment with Rheocarna, blood pressure tends to decrease at first, which later increases, and the higher the treatment volume, the longer the time of low blood pressure tended to be. Conclusion Although no significant difference was found in the removal rate of Fib and LDL in response to increase volume to 6 L or beyond in this study, the 6 L volume is considered effective enough for the removal of Fib and LDL.