Diagnostic and prognostic role of peak troponin T in patients with acute coronary syndromes and non-obstructive coronary arteries

Abstract

Abstract Background Up to 10% of patients who present with an acute coronary syndrome have a myocardial infarction with non-obstructive coronary arteries (MINOCA). Troponin T predicts infarct size and outcomes in patients with ST-elevation myocardial infarction. The value of peak troponin T in patients with a working diagnosis of MINOCA is not well understood. Purpose The aim of this study is to investigate the diagnostic and prognostic role of troponin in patients with MINOCA. Methods Consecutive patients with a working diagnosis of MINOCA from a single tertiary centre who underwent comprehensive cardiovascular magnetic resonance (CMR) imaging with late gadolinium enhancement (LGE) were followed prospectively. Peak troponin T was identified during the index admission and divided into deciles and quartiles for analysis. The primary endpoint was all-cause mortality. Results Among 796 patients undergoing CMR, 719 met the study criteria and had underwent a diagnostic quality scan. The peak Troponin T threshold for optimal diagnostic sensitivity and specificity was 211 ng/L. Peak troponin T ≥211 ng/L and time to CMR of ≤14 days has a sensitivity of 94%, specificity of 35%, PPV 57% and NPV 94% for the CMR making a diagnosis. Each increase in troponin decile increases the mean diagnostic yield of the CMR by 3.65% (p<0.001, 95% CI 3.38 – 3.91; R2 0.84; Figure 1). If the troponin is in the lowest decile and the CMR is performed at ≤14 days, the diagnostic yield is still 72%. There is no overall difference in median troponin in patients who died and those who survived (229 ng/l v. 424 ng/l; p=0.157), however mortality is significantly lower in the highest two troponin quartiles (6.9% versus 11.9%; p=0.009; Figure 2). Conclusion Peak troponin T is readily available during the index admission in patients presenting with MINOCA and provides useful diagnostic and prognostic information for the attending cardiologist. Funding Acknowledgement Type of funding sources: None. Figure 1. CMR diagnosis by troponin decileFigure 2. Mortality by troponin quartile