title: Treatment with or without plasma exchange for patients with acquired thrombotic microangiopathy not associated with severe ADAMTS13 deficiency: a propensity score-matched study.
abstract: Therapeutic plasma exchange (TPE) is a proven treatment for thrombotic thrombocytopenic purpura (TTP) characterized by severe ADAMTS13 deficiency, but the efficacy of TPE in suspected TTP with an ADAMTS13 activity level of more than 10% remains controversial.
  
  
  
  We conducted a propensity score (PS)-matched study of 186 adult patients included in the Harvard Thrombotic Microangiopathy (TMA) Research Collaborative registry who presented with TMA suggestive of TTP but an ADAMTS13 activity level of more than 10%.
  
  
  
  Before matching, patients treated with TPE (n = 71) differed from untreated patients (n = 115) by several clinical measures. PS matching was performed to address clinical disparities between the two groups and resulted in a well-balanced cohort of 59 TPE-treated patients paired with 59 untreated controls, all of whom had TMA. After matching, we observed no significant difference in the primary outcome of 90-day survival between the treated and untreated groups (hazard ratio, 0.88; 95% confidence interval [CI], 0.44-1.77; p = 0.72). In-hospital mortality (odds ratio [OR], 0.77; 95% CI, 0.34-1.75; p = 0.53) and the percentage of patients with platelet count recovery (OR, 1.58; 95% CI, 0.77-3.26; p = 0.21) also did not differ significantly between the two matched groups.
  
  
  
  Our data suggest that routine use of TPE in the diverse group of TMA patients without severe ADAMTS13 deficiency may not significantly improve outcomes.
authors.affiliation: Department of Medicine.|Harvard Medical School, Boston, Massachusetts.
authors.forename: Ang
authors.initials: A
authors.lastname: Li
authors.affiliation: Harvard Medical School, Boston, Massachusetts.|Blood Transfusion Service, Department of Pathology.
authors.forename: Robert S
authors.initials: RS
authors.lastname: Makar
authors.affiliation: Harvard Medical School, Boston, Massachusetts.|Center for Clinical Investigation.
authors.forename: Shelley
authors.initials: S
authors.lastname: Hurwitz
authors.affiliation: Harvard Medical School, Boston, Massachusetts.|Department of Pathology, Beth Israel Deaconess Medical Center.
authors.forename: Lynne
authors.initials: L
authors.lastname: Uhl
authors.affiliation: Harvard Medical School, Boston, Massachusetts.|Department of Pathology, Brigham and Women's Hospital.
authors.forename: Richard M
authors.initials: RM
authors.lastname: Kaufman
authors.affiliation: Harvard Medical School, Boston, Massachusetts.|Blood Transfusion Service, Department of Pathology.
authors.forename: Christopher P
authors.initials: CP
authors.lastname: Stowell
authors.affiliation: Harvard Medical School, Boston, Massachusetts.|Blood Transfusion Service, Department of Pathology.|Division of Hematology, Massachusetts General Hospital.
authors.forename: Walter S
authors.initials: WS
authors.lastname: Dzik
authors.affiliation: Harvard Medical School, Boston, Massachusetts.|Blood Transfusion Service, Department of Pathology.|Division of Hematology, Massachusetts General Hospital.
authors.forename: Pavan K
authors.initials: PK
authors.lastname: Bendapudi
mesh_terms: D000071120:ADAMTS13 Protein / Q000172:deficiency* / Q000235:genetics; D000328:Adult; D000368:Aged; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010951:Plasma Exchange / Q000379:methods*; D057216:Propensity Score; D011446:Prospective Studies; D012189:Retrospective Studies; D057049:Thrombotic Microangiopathies / Q000235:genetics / Q000628:therapy*
chemical_list: D000071120:ADAMTS13 Protein; C099604:ADAMTS13 protein, human