title: Cardiac biomarkers at high altitude.
abstract: BACKGROUND
  Classically, biomarkers such as the natriuretic peptides (NPs) BNP/NT-proBNP are associated with the diagnosis of heart failure and hs-cTnT with acute coronary syndromes. NPs are also elevated in pulmonary hypertension. High pulmonary artery systolic pressure (PASP) is a key feature of high altitude pulmonary edema (HAPE), which may be difficult to diagnose in the field. We have previously demonstrated that NPs are associated with high PASP and the presence of acute mountain sickness (AMS) in a small cohort at HA. We aimed to investigate the utility of several common cardiac biomarkers in diagnosing high PASP and AMS.
  
  
  METHODS
  48 participants were assessed post-trekking and at rest at three altitudes: 3833 m, 4450 m, and 5129 m. NPs, hs-cTnT and hsCRP, were quantified using immunoassays, PASP was measured by echocardiography, and AMS scores were recorded.
  
  
  RESULTS
  Significant changes occurred with ascent in NPs, hs-cTnT, hsCRP (all p<0.001) and PASP (p=0.006). A high PASP (≥40 mm Hg) was associated with higher NPs, NT-proBNP: 137±195 vs. 71.8±68 (p=0.001); BNP 15.3±18.1 vs. 8.7±6.6 (p=0.001). NPs were significantly higher in those with AMS or severe AMS vs. those without (severe AMS: NT-proBNP: 161.2±264 vs. 76.4±82.5 (p=0.008)). The NPs correlated with hsCRP. cTnT increased with exercise at HA and was also higher in those with a high PASP (13.8±21 vs. 7.8±6.5, p=0.018).
  
  
  CONCLUSIONS
  The NPs and hs-cTnT are associated with high PASP at HA and the NPs with AMS.
authors.affiliation: 1 Defence Medical Services , Whittington Barracks, Lichfield, United Kingdom .
authors.forename: Adrian
authors.initials: A
authors.lastname: Mellor
authors.forename: Christopher
authors.initials: C
authors.lastname: Boos
authors.forename: David
authors.initials: D
authors.lastname: Holdsworth
authors.forename: Joe
authors.initials: J
authors.lastname: Begley
authors.forename: David
authors.initials: D
authors.lastname: Hall
authors.forename: Andrew
authors.initials: A
authors.lastname: Lumley
authors.forename: Anne
authors.initials: A
authors.lastname: Burnett
authors.forename: Amanda
authors.initials: A
authors.lastname: Hawkins
authors.forename: John
authors.initials: J
authors.lastname: O'Hara
authors.forename: Stephen
authors.initials: S
authors.lastname: Ball
authors.forename: David
authors.initials: D
authors.lastname: Woods
mesh_terms: D000208:Acute Disease; D000328:Adult; D000531:Altitude; D000532:Altitude Sickness / Q000097:blood* / Q000175:diagnosis; D015415:Biomarkers / Q000097:blood*; D001794:Blood Pressure; D002097:C-Reactive Protein / Q000032:analysis; D015331:Cohort Studies; D015444:Exercise; D005260:Female; D006801:Humans; D006976:Hypertension, Pulmonary / Q000175:diagnosis*; D008297:Male; D008875:Middle Aged; D009051:Mountaineering / Q000502:physiology; D020097:Natriuretic Peptide, Brain / Q000097:blood; D045265:Natriuretic Peptides / Q000097:blood; D010446:Peptide Fragments / Q000097:blood; D011651:Pulmonary Artery / Q000503:physiopathology*; D012146:Rest; D020107:Troponin T / Q000097:blood
chemical_list: D015415:Biomarkers; D045265:Natriuretic Peptides; D010446:Peptide Fragments; D020107:Troponin T; C109794:pro-brain natriuretic peptide (1-76); D020097:Natriuretic Peptide, Brain; D002097:C-Reactive Protein
keywords: BNP; NT-proBNP; acute mountain sickness; hypobaric hypoxia; pulmonary artery systolic pressure