Association of early elevated cardiac troponin I concentration and longitudinal change after off-pump coronary artery bypass grafting and adverse events: a prospective cohort study

BACKGROUND: The elevation of troponin after coronary artery bypass grafting (CABG) is common This study aimed to investigate the association between very early cardiac troponin I (cTnI) concentration and its longitudinal change within 24 hours after CABG and 30-day adverse events. METHODS: This study prospectively enrolled 633 patients who underwent isolated off-pump CABG from January 2019 to May 2019. Serum cTnI levels were measured in all patients at two examinations within 24 hours postoperatively (1 hour and 12–18 hours), and a proportional hazards model was used to determine the association between cTnI levels and their change with adverse events, which were defined as a composite of 30-day mortality, stroke, heart failure, myocardial infarction (MI), and ventricular fibrillation. RESULTS: cTnI levels of the two examinations and absolute change of cTnI levels were significantly higher in the event group than in the non-event group (P<0.01, both). Earlier and later cTnI concentrations were associated with 30-day complications [adjusted hazard ration (HR) 1.598, 95% confidence interval (CI), 1.158–2.204 and HR 1.499, 95% CI, 1.228–1.831, respectively]. With regard to longitudinal change in cTnI levels, participants with persistently high levels of cTnI and those with progression from a low level to high level concentration experienced a significantly increased risk of adverse events than did participants who had a trend of persistently low cTnI levels (HR 3.105, 95% CI, 1.748–5.517 versus HR 2.944, 95% CI, 1.488–5.824). CONCLUSIONS: Longitudinal change in cTnI levels within 24 hours and early cTnI concentrations, even less than 1 hour after CABG, are associated with adverse events. These data will be useful in identifying patients at an increased risk of complications.