title: The LDH ratio as a marker for response to plasma exchange in HUS/TTP of the adult.
abstract: BACKGROUND
  Plasma exchange improved the outcome of thrombotic thrombocytopenic purpura (TTP)/hemolytic uremic syndrome (HUS) of the adult markedly, but a high number of non-responders remain. Identifying these patients at an early stage would help to optimize therapy.
  
  
  OBJECTIVE
  determine the value of serologic measures in predicting the response to plasma exchange.
  
  
  METHODS
  We performed a retrospective chart review of 30 patients with HUS/TTP of the adult treated with plasma exchange. According to the treatment protocol, a mean of 42 +/- 8.2 ml plasma per kilogram of body weight was exchanged daily for 3 days and continued every second day thereafter. Prior to each session, clinical status and serologic markers for hemolysis and kidney function were obtained. To assess the early individual response to plasma exchange, the decline of LDH from the first to the third cycle was calculated as: LDH concentration before the third session/LDH concentration before the first session (LDH ratio).
  
  
  RESULTS
  During the observation period (median 195, range 6-1500 days), 80% of the patients responded to therapy with plasmapheresis. None of the serologic measures or clinical signs obtained before initiation of plasma exchange showed a significant correlation with the outcome. After 2 sessions of plasma exchange, only LDH and platelet level had improved markedly in responding patients. The LDH ratio was the best predictive marker for the individual response. An LDH ratio < 0.6 predicted a favorable outcome with a sensitivity of 0.96 and a specificity of 0.83.
  
  
  CONCLUSIONS
  The LDH ratio might be a useful marker for separating patients responding to plasma exchange from those not responding at an early stage.
authors.affiliation: Department of Internal Medicine III, University Hospital Vienna, Austria.
authors.forename: M
authors.initials: M
authors.lastname: Haas
authors.forename: Z
authors.initials: Z
authors.lastname: Leko-Mohr
authors.forename: T
authors.initials: T
authors.lastname: Lang
authors.forename: M
authors.initials: M
authors.lastname: Jansen
authors.forename: P
authors.initials: P
authors.lastname: Knöbl
authors.forename: W H
authors.initials: WH
authors.lastname: Hörl
authors.forename: W
authors.initials: W
authors.lastname: Druml
mesh_terms: D000328:Adult; D015415:Biomarkers / Q000097:blood; D005260:Female; D006463:Hemolytic-Uremic Syndrome / Q000097:blood* / Q000401:mortality / Q000628:therapy*; D006801:Humans; D007770:L-Lactate Dehydrogenase / Q000097:blood*; D008297:Male; D008875:Middle Aged; D017063:Outcome Assessment, Health Care; D010951:Plasma Exchange; D011237:Predictive Value of Tests; D011697:Purpura, Thrombotic Thrombocytopenic / Q000097:blood* / Q000401:mortality / Q000628:therapy*; D015203:Reproducibility of Results; D012189:Retrospective Studies; D015996:Survival Rate; D013997:Time Factors
chemical_list: D015415:Biomarkers; D007770:L-Lactate Dehydrogenase