Long-term outcome of patients presenting with myocardial injury or myocardial infarction.

Aims: Patients with acute or chronic myocardial injury are frequently identified in the context of suspected myocardial infarction (MI). We aimed to investigate their long-term follow-up.

Methods and results: We prospectively enrolled 2714 patients with suspected MI and followed them for all-cause mortality and a composite cardiovascular endpoint (CVE; cardiovascular death, MI, unplanned revascularization) for a median of 5.1 years. Final diagnoses were adjudicated by two cardiologists according to the Fourth Universal Definition of MI, including 143 (5.3%) ST-elevation MI, 236 (8.7%) non-ST-elevation MI (NSTEMI) Type 1 (T1), 128 (4.7%) NSTEMI T2, 86 (3.2%) acute and 677 (24.9%) with chronic myocardial injury, and 1444 (53.2%) with other reasons for chest pain (reference). Crude event rates per 1000 patient-years for all-cause mortality were highest in patients with myocardial injury (81.6 [71.7, 92.3]), and any type of MI (55.9 [46.3, 66.7]), compared to reference (12.2 [9.8, 15.1]). Upon adjustment, all diagnoses were significantly associated with all-cause mortality. Moreover, patients with acute (adj-HR 1.92 [1.08, 3.43]) or chronic (adj-HR 1.59 [1.16, 2.18]) myocardial injury, and patients with NSTEMI T1 (adj-HR 2.62 [1.85, 3.69]) and ST-elevation MI (adj-HR 3.66 [2.41, 5.57]) were at increased risk for cardiovascular events.

Conclusion: Patients with myocardial injury are at a similar increased risk for death and cardiovascular events compared to patients with acute MI. Further studies need to determine appropriate management strategies for patients with myocardial injury.

Registration: Clinicaltrials.gov (NCT02355457).