Prognostic Value of High-Sensitivity Troponin T After On-Pump Coronary Artery Bypass Graft Surgery.

INTRODUCTION: High-sensitivity troponin T (hs-TnT), as a single or serial measurement to predict postoperative mortality and morbidity, appears to be attractive due to its direct relationship in assessing myocardial damage and the widespread availability of hs-TnT testing. Therefore, this study aimed to identify any prognostic value of hs-TnT in predicting in-hospital outcomes after coronary artery bypass graft (CABG) surgery. METHOD: We identified all consecutive patients who underwent on-pump CABG between July 2011 and December 2018. To evaluate the prognostic value of hs-TnT after CABG, we assessed the probability and odds ratio (OR) of adverse events concerning the maximum value of postoperative hs-TnT (measured within 24 hrs). TnT was routinely collected at 0, 6, 12 and 72 hours postoperatively. Values were categorised into intervals of 200 for analysis. A fully Bayesian logistic regression of the adverse event with the troponin T interval (0-200) as the reference level was used. A subgroup analysis was performed in patients with normal and elevated preoperative hs-TnT (< or ≥30 ng/L). The pre-specified primary outcome was a major adverse cardiac or cerebrovascular event (MACCE), defined as a composite of death within 30 days of operation for any cause, myocardial infection (MI), or stroke. RESULTS: 1,318 people underwent on-pump CABG during this period. One hundred and twenty-three (123) (9.3%) experienced MACCE, 14 (1.1%) experienced death within 30 days, 105 (8.0%) experienced MI and 14 (1.1%) experienced stroke. Compared to the reference category (hs-TnT ≤200 ng/L) we found there was an increase in OR with increasing level of hs-TnT for MACCE (p<0.001), 30-day mortality (p=0.003), MI (p<0.001) and ICU stay >48 hours (p<0.001). However, there was no statistically significant association present between hs-TnT and stroke, readmission to the intensive care unit (ICU), return to theatre for bleeding, or new-onset renal dysfunction. CONCLUSION: Peak hs-TnT level, greater than 400 ng/L, measured within 24 hours after CABG surgery is associated with MACCE, 30-day mortality, MI and ICU stay >48 hours. Prospectively designed trials, with clear prognostic and outcome variables, may provide further insight into the prognostic value of hs-TnT post-CABG.

The long-term mortality of an Aboriginal and Torres Strait Islander Australian population after isolated coronary artery bypass graft surgery.

BACKGROUND: Aboriginal and Torres Strait Islander (Indigenous) Australians have an increased prevalence of coronary artery disease and present at a younger age for coronary artery bypass graft surgery (CABG) when compared to non-Indigenous Australians. Studies have reported postoperative outcomes in Indigenous people to be less favourable. Therefore, the aim of this study is to evaluate long term mortality between Indigenous and non-Indigenous people post-CABG. METHODS: We analysed data on all patients who underwent isolated CABG, with and without cardiopulmonary bypass, at our institution between January 1998 to September 2008. There were 33 395 person-years of survival for analysis with a median follow-up of 13 years (Interquartile range (IQR): 8-16 years). We analysed all-cause mortality with the Kaplan-Meier graph and log-rank test. Univariate and multivariate analysis was performed using a Cox proportional hazards model. RESULTS: The mean age at presentation for Indigenous people was 52 years compared to 65 yr for non-indigenous people. There were 1431 (52.1%) deaths by the study census date, with the overall mortality for Indigenous patients at 49.8% (n = 147) and 52.4% for non-Aboriginal patients (n = 1284). The age and comorbidities adjusted hazard ratio (HR) for all-cause late mortality (median years) was HR = 1.712 (95% CI: 1.288-2.277, p < 0.001). CONCLUSION: Indigenous patients present for CABG at a younger age and have a higher prevalence of comorbidities. Our study demonstrates they have a higher risk of propensity adjusted all-cause long term mortality. Primary and secondary prevention strategies, tailored to Indigenous people, may improve health outcomes in the long-term post-CABG.