Acute versus chronic myocardial injury and long-term outcomes

Abstract

Objective: There is a paucity of data regarding prognosis in patients with acute versus chronic myocardial injury for long-term outcomes. We hypothesised that patients with chronic myocardial injury have a similar long-term prognosis as patients with acute myocardial injury.

Methods: In an observational cohort study of 22 589 patients who had high-sensitivity cardiac troponin T (hs-cTnT) measured in the emergency department during 2011-2014, we identified all patients with level >14 ng/L and categorised them as acute myocardial injury, type 1 myocardial infarction (T1MI), type 2 myocardial infarction (T2MI) or chronic myocardial injury through adjudication. We estimated adjusted HRs with 95% CIs for the primary outcome all-cause mortality and secondary outcomes MI, and heart failure in patients with acute myocardial injury, T1MI and T2MI compared with chronic myocardial injury.

Results: In total, 3853 patients were included. During 3.9 (±2) years of follow-up, 48%, 24%, 44% and 49% of patients with acute myocardial injury, T1MI, T2MI and chronic myocardial injury died, respectively. Patients with acute myocardial injury had higher adjusted risks of death (1.21, 95% CI 1.08 to 1.36) and heart failure (1.24, 95% CI 1.07 to 1.43), but a similar risk for myocardial infarction (MI) compared with the reference group. Patients with T1MI had a lower adjusted risk of death (0.86, 95% CI 0.74 to 1.00) and higher risk of MI (2.09, 95% CI 1.62 to 2.68), but a similar risk of heart failure. Patients with T2MI had a higher adjusted risk of death (1.46, 95% CI 1.18 to 1.80) and heart failure (1.30, 95% CI 1.00 to 1.69) compared with patients with chronic myocardial injury.

Conclusions: Absolute long-term risks for death are similar, and adjusted risks are slightly higher, among patients with acute myocardial injury and T2MI, respectively, compared with chronic myocardial injury. The lowest risk of long-term mortality was found in patients with T1MI. Both acute and chronic myocardial injury are associated with very high risks of adverse outcomes.

Keywords: cardiac risk factors and prevention; coronary artery disease; epidemiology.