Management and outcomes with 5-year mortality of patients with mildly elevated high-sensitivity troponin T levels not meeting criteria for myocardial infarction

Objectives: To examine management and outcomes of patients presenting to EDs with symptoms suggestive of acute coronary syndrome, who have mild non-dynamically elevated high-sensitivity troponin T (HsTnT) levels, not meeting the fourth universal definition of myocardial infarction (MI) criteria (observation group). Methods: Consecutive patients presenting to the ED with symptoms suggestive of acute coronary syndrome at Liverpool Hospital, Sydney, Australia, those having >= 2 HsTnT levels after initial assessment were adjudicated according to the fourth universal definition of MI, as MI ruled-in, MI ruled-out, or myocardial injury in whom MI is neither ruled-in nor ruled-out (>1 level >= 15 ng/L, called observation group); follow-up was 5 years. Results: Of 2738 patients, 547 were in the observation group, of whom 62% were admitted to hospital, 52% to cardiac services, whereas 97% of MI ruled-in patients and 21% of MI ruled-out patients were admitted; P < 0.001. Non-invasive testing occurred in 42% of observation group patients (36% had echocardiography), and 16% had coronary angiography. Of observation group patients, MI rates were 1.5% during hospitalisation and 4% during the following year, similar to that in those with MI ruled-in, among those with MI ruled-out, the MI rate was 0.2%. The 1-year death rate was 13% among observation group patients and 11% MI ruled-in patients (P = 0.624), whereas at 5 years among observation group patients, type 1 MI and type 2 MI were 48%, 26% and 58%, respectively (P = 0.001). Conclusion: Very few unselected consecutive patients attending ED, with minor stable HsTnT elevation, had MI, although most had chronic myocardial injury. Late mortality rates among observation group patients were higher than those with confirmed type 1 MI but lower than those with type 2 MI.