Cardiac Biomarkers at High Altitude

Mellor, Adrian, Christopher Boos, David Holdsworth, Joe Begley, David Hall, Andrew Lumley, Anne Burnett, Amanda Hawkins, John O'Hara, Stephen Ball, and David Woods. Cardiac biomarkers at high altitude. High Alt Med Biol 15:452-458, 2014.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: 3833m, 4450m, and 5129m. 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 (40mm Hg) was associated with higher NPs, NT-proBNP: 137195 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). Conclusion: The NPs and hs-cTnT are associated with high PASP at HA and the NPs with AMS.