Therapeutic Plasma Exchange Using Membrane Plasma Separation Across a Broad Spectrum of Indications: An Eight-Year Single-Center Retrospective Cohort Study.

Background: Therapeutic plasma exchange (TPE) removes pathogenic plasma constituents such as autoantibodies, immune complexes and monoclonal proteins. Plasma can be separated by centrifugation or by membrane plasma separation (MPS); although MPS predominates in many centers because it can be delivered at the bedside on standard renal replacement platforms, most published outcome data derive from centrifugal techniques. Objective: To describe the indications, complications, laboratory changes and clinician-assessed treatment response of MPS-based TPE in an unselected single-center cohort. Methods: All 131 patients who underwent TPE by MPS at a tertiary training and research hospital between January 2009 and March 2017 were retrospectively reviewed. Demographic data, indications, session numbers, vascular access, replacement fluid, dialysis and immunosuppressive status, procedure-related complications, and laboratory parameters obtained before the first and after the last TPE session were recorded. Treatment response was categorized by the treating physician as complete, partial or absent, based on resolution of disease-specific clinical findings and laboratory abnormalities. Results: Mean age was 44.0 ± 17.0 years (48.9% female). The most frequent indications were granulomatosis with polyangiitis/microscopic polyangiitis (18.3%) and thrombotic thrombocytopenic purpura/hemolytic uremic syndrome (14.5%). Sixty-nine complications occurred over 967 sessions (7.1%), most commonly hypocalcemia (26.0% of patients), allergic reactions (9.9%) and hypotension (6.9%); none were fatal. Urea (p=0.024), creatinine (p<0.001), LDH (p=0.001) and total protein (p=0.035) decreased significantly, while albumin increased (p<0.001). Complete and partial responses were recorded in 24.8% and 38.9% of patients, respectively. Response rates did not differ significantly by indication or by ANCA/anti-GBM status. Conclusion: In this retrospective single-center cohort, MPS-based TPE was performed across a wide range of indications with a low procedure-related complication rate and favorable short-term laboratory and clinical outcomes. As no comparator group was included, these findings describe institutional experience and do not establish the comparative effectiveness of MPS.