title: Survival and relapse in patients with thrombotic thrombocytopenic purpura.
abstract: Survival of patients with thrombotic thrombocytopenic purpura (TTP) improved dramatically with plasma exchange treatment, revealing risk for relapse. The Oklahoma TTP Registry is a population-based inception cohort of all 376 consecutive patients with an initial episode of clinically diagnosed TTP (defined as microangiopathic hemolytic anemia and thrombocytopenia with or without signs and symptoms of ischemic organ dysfunctions) for whom plasma exchange was requested, 1989 to 2008. Survival was not different between the first and second 10-year periods for all patients (68% and 69%, P = .83) and for patients with idiopathic TTP (83% and 77%, P = .33). ADAMTS13 activity was measured in 261 (93%) of 282 patients since 1995. Survival was not different between patients with ADAMTS13 activity < 10% (47 of 60, 78%) and patients with 10% or more (136 of 201, 68%, P = .11). Among patients with ADAMTS13 activity < 10%, an inhibitor titer of 2 or more Bethesda units/mL was associated with lower survival (P = .05). Relapse rate was greater among survivors with ADAMTS13 activity < 10% (16 of 47, 34%; estimated risk for relapse at 7.5 years, 41%) than among survivors with ADAMTS13 activity of 10% or more (5 of 136, 4%; P < .001). In 41 (93%) of 44 survivors, ADAMTS13 deficiency during remission was not clearly related to subsequent relapse.
authors.affiliation: Department of Hematology and Central Hematology Laboratory, Inselspital, Berne University Hospital and University of Berne, Berne, Switzerland.
authors.forename: Johanna A
authors.initials: JA
authors.lastname: Kremer Hovinga
authors.forename: Sara K
authors.initials: SK
authors.lastname: Vesely
authors.forename: Deirdra R
authors.initials: DR
authors.lastname: Terrell
authors.forename: Bernhard
authors.initials: B
authors.lastname: Lämmle
authors.forename: James N
authors.initials: JN
authors.lastname: George
mesh_terms: D051722:ADAM Proteins / Q000097:blood*; D000071120:ADAMTS13 Protein; D018572:Disease-Free Survival; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D009825:Oklahoma; D010951:Plasma Exchange; D011480:Protease Inhibitors / Q000097:blood*; D011697:Purpura, Thrombotic Thrombocytopenic / Q000097:blood* / Q000401:mortality* / Q000628:therapy; D012008:Recurrence; D012042:Registries; D012189:Retrospective Studies; D015996:Survival Rate
chemical_list: D011480:Protease Inhibitors; D051722:ADAM Proteins; D000071120:ADAMTS13 Protein; C099604:ADAMTS13 protein, human