Is cardiac troponin elevation following strenuous exercise clinically relevant in healthy subjects?

Abstract Background Exercise causes an increase in cardiac troponin (cTn) levels. Exercise-induced myocardial injury (cTn > the 99th percentile) has been associated with adverse cardiovascular (CV) outcomes in older subjects with CV risk factors. The long-term clinical implications of exercise-induced cardiac troponin elevations in healthy individuals has not been determined. Purpose To assess the association between exercise-induced cardiac troponin increase above the 99th percentile and all-cause death, myocardial infarction, revascularization, sudden cardiac arrest, heart failure admission and stroke during 5-years follow-up in a large cohort of healthy recreational athletes. Methods 1002 healthy subjects that completed a 91-km bike race in 2014 were eligible. Follow-up data was available for 991 subjects (99%). High-sensitivity cardiac troponin I (cTnI) and T (cTnT) were obtained 24h prior to the race, and at 3h and 24h after the race in 2014. Results Median age was 46 (25th-75th percentile: 40–53) years at inclusion, and 776 (78%) were male. Race duration was 3.8 (3.4–4.3) hours. At 3-hours following the race 821 (82.8%) of subjects exceeded the sex-specific 99th percentile of the cTnI assay and 910 (91.8%) of the cTnT assay. At 24-hours following the race 168 (17%) of subjects exceeded the sex-specific 99th percentile of the cTnI assay and 263 (27%) of the cTnT assay. During 5 years of follow-up 12 subjects (1.2%) suffered a CV event. Exercise-induced cardiac troponin increase above the 99th percentile was not associated with increased risk of adverse CV events, neither at 3-hours nor at 24-hours following the race (Figure 1). This finding was further supported by no significant relationship between adverse CV events and cTnI or cTnT at any time-point, assessed as continuous variables. Conclusion Myocardial injury, defined as a cardiac troponin level above the 99th percentile, occurs frequently following strenuous exercise. In the present study, however, healthy subjects with cardiac troponin increase above the 99th percentile following strenuous exercise were not found to have an increased five-year risk of cardiovascular events. frequent occurrence following strenuous exercise. Figure 1 Funding Acknowledgement Type of funding source: Foundation. Main funding source(s): Stavanger University Hospital, Abbott Diagnostics