Outcomes in patients with thrombotic microangiopathy associated with a trigger following plasma exchange: A systematic literature review.

Plasma exchange (PE) outcomes in patients with trigger-associated thrombotic microangiopathy (TMA) have not been comprehensively reviewed. Embase and MEDLINE® were searched on 03/14/2022 for English language articles published after 2007, alongside a congress materials search (2019-2022; PROSPERO: CRD42022325170). Studies with patients with trigger-associated TMA (excluding thrombotic thrombocytopenic purpura, 'typical' hemolytic uremic syndrome caused by Shiga toxin-producing Escherichia coli, post-partum TMA, and TMAs with known genetic cause) who received PE or plasma infusion (PI) and reported treatment response (including measures), safety, patient-/caregiver-reported outcomes, or economic burden data were examined. The NICE quality appraisal checklist assessed bias risk. After screening 695 articles, 49 PE or PI studies were identified, of which 42 reported PE exclusively; most were retrospective observational studies (n = 37). The most common TMA trigger was transplantation (n = 12). The median number of PE sessions was 3.5-25.0. Outcomes following PE varied by trigger type. Treatment response rates and definitions varied (0-100 %; 24 studies); in studies of > 25 patients, response rates were 5-63 %. TMA relapse rates were 0-67 % (7 studies). Mortality was 10-91 % (23 studies). Progression to chronic kidney disease (CKD; 5 studies) and end-stage renal disease (ESRD; 6 studies) occurred in 0-93 % and 17-100 % of patients, respectively. Two serious adverse events were identified (transfusion-related injury, acute lung injury; 10 studies; 231 patients). Patients with trigger-associated TMA may experience a substantial burden in terms of mortality, relapse, and progression to CKD and ESRD following PE, leading to increased healthcare resource utilization. Additional interventions may be required.