Diagnosis of myocardial infarction and prognostic utility of high-sensitivity troponin T after isolated aortic valve replacement

Abstract

Background

The Universal Definition for type 5 myocardial infarction (MI) applies to coronary artery bypass grafting (CABG), while MIs for other cardiac surgery are not specifically defined. We assessed whether elevated high-sensitivity troponin (hs-TnT), with electrocardiogram (ECG) changes and/or new wall motion abnormalities on echocardiography as defined by the Universal Definition, predicted mortality and/or morbidity after aortic valve replacement (AVR) (n = 219).

Methods

Consecutive patients with isolated AVR performed during July 2010–December 2012 and followed-up for 2.3 ± 0.8 years. Hs-TnT was measured 12–24 h post-operatively. ECG and/or echocardiographic changes with hs-TnT > 140 ng/L (10 times 99th percentile upper reference limit and > 500 ng/L (10 times the coefficient of variation of 10% for 4th generation troponin T applied to hs-TnT) were pre-specified as the criteria for MI diagnosis.

Results

There were 9.1% (20) and 3.7% (8) patients with ECG and/or echocardiographic changes and hs-TnT > 140 ng/L and hs-TnT > 500 ng/L respectively. Neither criterion was independently associated with 30-day mortality (2.7%). Hs-TnT > 500 ng/L and ECG and/or echocardiographic changes was independently associated with mortality (5.5%) during follow-up, hazards ratio 5.23, 95% confidence interval 1.09–25.2, p = 0.039. Hs-TnT per 100 ng/L as a continuous parameter was independently associated with 30-day mortality, mortality during follow-up and composite morbidity.

Conclusion

The Universal Definition of MI, using 10 times the URL for the 4th generation troponin T and 35 times the URL for hs-TnT with a cutpoint of > 500 ng/L with ECG and/or echocardiographic changes, independently predicted median term mortality after AVR. Hs-TnT as a continuous parameter was independently associated with mortality at both time points and morbidity.