Prolonged Elevated Cardiac Troponin After Marathon Running Is A Sign For Myocardial Damage

Abstract

PURPOSE:The pathophysiological mechanism of cardiac troponin (cTn) elevation after marathon running is still not clear. It is discussed controversially whether (especially a prolonged) elevation reflects rather physiological than pathological processes. We hypothesized that a prolonged elevation of cTn (pecTn) post-marathon is associated with late gadolinium enhancement (LGE) in cardiac magnetic resonance (CMR) imaging as a sign of myocardial damage. METHODS: We examined cTn T values in 162 healthy male marathon runner (age: 42.1 ± 10.9 yrs) before (V2) and immediately (V3), 24 hrs (V4), and 72 hrs (V5) after a marathon race. A pecTn was defined as follows: a high-sensitive cTnT > 25 ng/L at V4 or > 14 ng/L at V5. The participants with pecTn were compared to controls without pecTn which were similar with respect to age and previous finished long-distance races. Both groups were examined with CMR in the days post-race and those with LGE in the first CMR also with a second CMR approximately 3 month post-race. RESULTS: We examined in total 22 out of 162 runners (13.6%). 12 of 162 (7.4%, age 38.7 ± 10.4 yrs) had prolonged elevated cTn T values. 7 in the pecTn group (58.3%) and 2 in the control group (20%, p = 0.099) had a LGE in the first CMR. In the second CMR, 5 participants in the pecTn group (41.7%) and 1 in the control group (10%, p = 0.162) presented LGE. In the ROC analyses, cTnT values immediately post-race were not associated with LGE (1st CMR: AUC = 0.671, p = 0.182, 2nd CMR: AUC = 0.474, p = 0.854). However, LGE in first CMR was significantly associated with cTnT at V4 (AUC = 0.769, p = 0.035) and LGE in second MRI with cTnT at V5 (AUC = 0.807, p = 0.030), however not reaching level of significance for V4 (AUC = 0.750, p = 0.077). Regarding mean cTn values at V4 and V5, LGE in both CMRs were significantly associated with cTn values (first CMR: AUC = 0.752, p = 0.049; second CMR: AUC = 0.828, p = 0.020). An optimal cut-point regarding LGE at the first MRI determined by maximizing the Youden index for a cTn value at 24 hrs post-race was found at 23.5 ng/L (estimated sensitivity: 66.7 %, specificity: 84.6 %). CONCLUSIONS: Prolonged elevation of cTn after marathon running is associated with LGE in CMR and therefore, seems to be a sign for myocardial damage. Furthermore, high-sensitive cTnT values ≥ 24 ng/L 24 hrs post-race are highly suspicious for a pathological process.