title: Raised erythrocyte creatine in patients with pulmonary arterial hypertension--evidence for subclinical hemolysis.
abstract: BACKGROUND
  Pulmonary arterial hypertension (PAH) has been associated with hemolytic conditions such as sickle cell disease but the possible role of hemolysis in the pathogenesis or pathophysiology of other forms of PAH has not been studied. Erythrocyte lifespan is the gold-standard test of hemolysis and may be measured by assaying erythrocyte creatine (EC) levels. EC decreases as the erythrocyte ages, so patients with hemolysis have high EC levels.
  
  
  METHODS
  We measured EC and other parameters of hemolysis in patients with idiopathic and connective tissue associated PAH and normal controls.
  
  
  RESULTS
  In patients with PAH (n = 40), EC levels were higher than in controls n = 30 (patients EC 1.72 mcmol/g HgB 95%CI[1.51, 1.96], controls EC 1.05 mcmol/g HgB [0.93, 1.19], p < 0.0001). High levels of EC correlated with worse 6 min walk (r = -0.42, p < 0.0001) and worse functional class (p = 0.002). Other indirect indices of hemolysis (total lactate dehydrogenase, red cell distribution width) were also increased in patients with PAH relative to controls.
  
  
  CONCLUSIONS
  There is evidence of subclinical hemolysis in patients with PAH, and higher levels of hemolysis are associated with poorer exercise capacity.
authors.affiliation: Pulmonary Institute, Rabin Medical Center, Petach Tiqwa 49100, Israel. benfox@post.tau.ac.il
authors.forename: Benjamin D
authors.initials: BD
authors.lastname: Fox
authors.forename: Toshika
authors.initials: T
authors.lastname: Okumiya
authors.forename: Liat
authors.initials: L
authors.lastname: Attas-Fox
authors.forename: Michael
authors.initials: M
authors.lastname: Kassirer
authors.forename: Yael
authors.initials: Y
authors.lastname: Raviv
authors.forename: Mordechai R
authors.initials: MR
authors.lastname: Kramer
mesh_terms: D000328:Adult; D001800:Blood Specimen Collection / Q000379:methods; D016022:Case-Control Studies; D003401:Creatine / Q000097:blood*; D004912:Erythrocytes / Q000737:chemistry*; D065627:Familial Primary Pulmonary Hypertension; D005260:Female; D005500:Follow-Up Studies; D006461:Hemolysis / Q000502:physiology*; D006801:Humans; D006976:Hypertension, Pulmonary / Q000097:blood* / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D016138:Walking / Q000502:physiology
chemical_list: D003401:Creatine