Evaluation of membrane‐based therapeutic plasma exchange as adjunctive treatment for immune‐mediated hematologic disorders in dogs

BACKGROUND: Therapeutic plasma exchange (TPE) has been used increasingly to treat immunological diseases in dogs, although data concerning its efficacy are lacking. HYPOTHESIS/OBJECTIVES: To describe the clinic and the outcome of dogs with immune‐mediated hematological disorders (IMHD) treated with membrane filtration TPE. ANIMALS: One hundred forty‐six dogs diagnosed with IMHD, including 17 dogs treated with and 129 control dogs treated without TPE. METHODS: Retrospective study of cases selected with a search of all medical records for dogs diagnosed with IMHD (2010‐2019). Primary outcomes included the assessment of safety and efficacy of adjunctive TPE compared to medical treatment alone. RESULTS: The TPE group included 7 dogs with immune‐mediated hemolytic anemia (IMHA), 5 dogs with immune‐mediated thrombocytopenia (IMT), and 5 dogs with combined IMHA‐IMT; the control group included 63 dogs with IMHA, 47 dogs with IMT, and 19 dogs with IMHA‐IMT. Dogs treated with TPE were more often refractory to initial immunosuppression (71%) than controls (43%; P = .04). Complications were observed in 15/43 TPE treatments (35%). The response rate of dogs treated with TPE was 83% in IMHA (controls, 65%; P = .5) and 80% in IMT (controls, 70%; P = .71). Overall, 12/17 dogs (71%) treated with TPE reached complete remission, 2/17 (12%) partial remission, and 3/17 (18%) died or were euthanized. Eighty‐two percent of the dogs treated with TPE survived to discharge (controls, 69%; P = .4). CONCLUSIONS AND CLINICAL IMPORTANCE: Despite a bias toward dogs refractory to initial immunosuppression, dogs treated with adjunctive TPE had a similar outcome as dogs treated medically.