Outcomes of plasma exchange in patients with transplant-associated thrombotic microangiopathy based on time of presentation since transplant.

Transplant-associated thrombotic microangiopathy (TA-TMA) is a rare clinical syndrome associated with significant mortality. Although the use of plasma exchange (PE) in TA-TMA continues to be explored, evidence for its efficacy is debated. We performed a single institution, retrospective study to evaluate the efficacy of PE in treating TA-TMA patients. Special attention was given to efficacy in relation to the timing of presentation with TA-TMA since transplant. Thirty-three patients diagnosed with TA-TMA and treated with PE between January 1999 and December 2010 were included in the study. Clinical improvement was seen in eight patients (24%); four patients achieved complete resolution while the remaining four achieved partial resolution. All-cause day-30 and day-100 mortality was 33 and 55%, respectively. There was a trend toward a better outcome (complete/partial) for those presenting ≥ 100 days after transplantation (42%) vs. < 100 days after transplantation (14%; P-value = 0.15). Similarly, those presenting at ≥ 100 days had better, but not significantly, 30-day and 100-day all-cause mortality rates (17 and 33%, respectively) than those presenting at < 100 days (43 and 67%, respectively) (P-value = 0.25 and 0.08, for 30- and 100-day all-cause mortality, respectively). This is the first study looking at the efficacy of PE while considering the time of presentation since transplantation and is one of the largest single institution series of TA-TMA. The overall efficacy of PE is poor; however, patients who present with TA-TMA ≥100 days after transplant may have better outcome and lower mortality.