Does Preoperative Troponin Level Impact Outcomes After Coronary Artery Bypass Grafting?

BACKGROUND

As a marker of myocardial injury, troponin level correlates with adverse outcomes after myocardial infarction (MI). We hypothesized that patients with a higher preoperative troponin level would have increased morbidity and mortality after coronary artery bypass grafting (CABG).

METHODS

Preoperative troponin measurements were available for 1,272 patients who underwent urgent or emergent isolated CABG at our institution from 2002 to 2016. Logistic regression assessed the risk-adjusted effect of peak troponin level on morbidity and mortality. Long-term survival analysis was performed with Kaplan-Meier and Cox proportional hazards models.

RESULTS

Preoperative troponin was positive in 835 patients (65.6%). The median peak troponin for this group was 3.2 ng/mL (interquartile range, 0.6 to 11.9 ng/mL), with a median time from peak troponin to the operation of 3 days (interquartile range, 1 to 4 days). Positive troponin was associated with more significant comorbid conditions and more extensive coronary artery disease. Operative mortality (3.7% versus 1.1%, p = 0.009), major morbidity (11.7% versus 3.9%, p < 0.001), and long-term mortality (median survival 12.5 years versus 13.6 years, p = 0.01) were increased in the positive troponin group. After risk adjustment, positive troponin was not independently associated with increased operative mortality (odds ratio, 2.61; p = 0.053). Adjusted and unadjusted analysis showed the peak preoperative troponin level did not independently predict death at any time point (all odds ratios, 1.0; p > 0.05).

CONCLUSIONS

A positive preoperative troponin correlates with worse outcomes after CABG, but risk adjustment eliminates much of the short-term predictive value of this biomarker. Peak troponin level does not influence outcomes after CABG and is a poor predictor of events when The Society of Thoracic Surgeons predictive models are used.