Intraprocedural Hemodynamics During Concomitant Rheocarna Therapy and Maintenance Hemodialysis: Effects of Dialyzer Membrane Type and Circuit Sequence

ABSTRACT Chronic limb‐threatening ischemia (CLTI), a severe manifestation of peripheral artery disease, is particularly prevalent among patients receiving maintenance hemodialysis (HD) and is associated with poor limb and survival outcomes. Low‐density lipoprotein (LDL) apheresis, including Rheocarna, is used as adjunctive therapy for refractory CLTI; however, intraprocedural hypotension remains a major limitation, especially when combined with HD. We examined the effects of dialyzer membrane type and extracorporeal circuit sequence on hemodynamic stability during concomitant therapy. This case series comprised two patients with CLTI receiving maintenance HD. Each patient underwent four treatment sessions representing the four configurations defined by two dialyzer membranes (polysulfone [PS] and AN69) and two circuit sequences (Rheocarna → dialyzer vs. dialyzer → Rheocarna). Hemodynamic parameters, including systolic blood pressure, relative blood volume change (ΔBV), and peripheral microvascular perfusion assessed by laser Doppler flowmetry (ΔLDF), were assessed during each treatment session. In both cases, the Rheocarna → AN69 configuration showed the smallest early decrease in systolic blood pressure and the most favorable early ΔBV pattern among the four sessions. Toe ΔLDF was preserved or increased with this configuration. The other three configurations were associated with larger early decreases in systolic blood pressure in one or both patients, including a decrease to below 90 mmHg in Case B. These findings suggest that dialyzer membrane type and circuit sequence may influence intraprocedural hemodynamic stability during concomitant Rheocarna therapy and HD. Among the tested configurations, Rheocarna → AN69 showed better hemodynamic tolerance and preservation of peripheral perfusion. These hypothesis‐generating findings warrant further evaluation in larger prospective studies.