title: Clinical outcomes after platelet transfusions in patients with thrombotic thrombocytopenic purpura.
abstract: BACKGROUND
  Reports of deterioration and death after platelet (PLT) transfusions in patients with thrombotic thrombocytopenic purpura (TTP) have led to recommendations that they should not be given except for life-threatening hemorrhage.
  
  
  METHODS
  Published reports of PLT transfusions in patients with TTP were systematically reviewed and data from the Oklahoma TTP-HUS Registry, an inception cohort of 382 consecutive patients, 1989 through 2007, were analyzed.
  
  
  RESULTS
  A systematic review identified 34 publications describing outcomes of patients with TTP after PLT transfusions: 9 articles attributed complications to PLT transfusions, 4 suggested that they may be safe, and 21 articles did not comment about a relation between PLT transfusions and outcomes. Fifty-four consecutive patients from the Oklahoma TTP-HUS Registry were prospectively analyzed. ADAMTS13 activity was less than 10 percent in 47 patients; also included were 7 patients whose activity was not measured but who may have been deficient. Thirty-three (61%) patients received PLT transfusions. The frequency of death was not different between the two groups (p = 0.971): 8 (24%) patients who received PLT transfusions died (thrombosis, 5; hemorrhage, 1; sepsis, 2) and 5 (24%) patients who did not receive PLT transfusions died (thrombosis, 4; hemorrhage, 1). The frequency of severe neurologic events was also not different (p = 0.190): 17 (52%) patients who received PLT transfusions (in 5 of these 17 patients, neurologic events only occurred before PLT transfusions) and 7 (33%) patients who did not receive PLT transfusions.
  
  
  CONCLUSIONS
  Evidence for harm from PLT transfusions in patients with TTP is uncertain.
authors.affiliation: Hematology-Oncology Section, Department of Medicine, The University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, USA.
authors.forename: Karen K
authors.initials: KK
authors.lastname: Swisher
authors.forename: Deirdra R
authors.initials: DR
authors.lastname: Terrell
authors.forename: Sara K
authors.initials: SK
authors.lastname: Vesely
authors.forename: Johanna A
authors.initials: JA
authors.lastname: Kremer Hovinga
authors.forename: Bernhard
authors.initials: B
authors.lastname: Lämmle
authors.forename: James N
authors.initials: JN
authors.lastname: George
mesh_terms: D051722:ADAM Proteins / Q000172:deficiency; D000071120:ADAMTS13 Protein; D002423:Cause of Death; D006801:Humans; D009422:Nervous System Diseases / Q000209:etiology; D017713:Platelet Transfusion / Q000009:adverse effects* / Q000401:mortality / Q000706:statistics & numerical data; D011697:Purpura, Thrombotic Thrombocytopenic / Q000628:therapy*; D012042:Registries; D015996:Survival Rate; D016896:Treatment Outcome
chemical_list: D051722:ADAM Proteins; D000071120:ADAMTS13 Protein; C099604:ADAMTS13 protein, human