Clinical dissection of thrombotic microangiopathy

Differential treatment strategies are applied in thrombotic microangiopathy (TMA) according to the sub-classifications. Hence, it is worthwhile to overview clinical manifestations and outcomes of overall TMA patients according to sub-classifications. We analyzed TMA patients whose serum lactate dehydrogenase levels > 250 IU/L, with the presence of schistocytes in their peripheral blood smear, or with typical vascular pathologic abnormalities in their renal biopsy. We compared clinical manifestations including overall survival (OS) and renal survival according to TMA causes. A total of 117 TMA patients (57 primary and 60 secondary TMA) were analyzed. Renal symptom was the most common manifestation in whole patients, while renal function at diagnosis was worst in pregnancy-related TMA group. Primary TMA patients had more frequent CNS symptom and hematologic manifestation compared to secondary TMAs. Among secondary TMAs, pregnancy- and HSCT-related TMA patients showed prevalent hemolytic features. During 150.2 months of follow-up, 5-year OS rate was 64.8%. Poor prognostic factors included older age, combined hematologic and solid organ malignancies, lower hemoglobin levels, and lower serum albumin levels. There was no significant difference in OS between primary and secondary TMAs. Seventy-eight percent of patients experienced AKI during TMA. Five-year death-censored renal survival rate was poor with only 69.2%. However, excellent renal outcome was observed in pregnancy-associated TMA. TMA showed various clinical manifestations according to their etiology. Notably, both OS and renal survival were poor regardless of their etiologies except pregnancy-associated TMA. Physicians should differentiate a variety of TMA categories and properly manage this complex disease entity.