Outcomes in Type 2 MI and Myocardial Injury

Study Questions:

What are the long-term outcomes among patients with type 1 myocardial infarction (MI), type 2 MI, or myocardial injury?

Methods:

The authors evaluated 2,122 consecutive patients with elevated cardiac troponin I concentrations at a single tertiary care cardiac center. Patients were divided into those with type 1 MI, type 2 MI, or myocardial injury. Myocardial injury was defined as evidence of myocardial necrosis in the absence of any symptoms or signs of myocardial ischemia. The primary outcome was all-cause death at 5 years. The secondary outcome included major adverse cardiac outcomes (MACE), defined as nonfatal MI or cardiovascular death.

Results:

A total 52% (n = 1,171), 20% (n = 429), and 25% (n = 522) of patients presented with type I MI, type 2 MI, and myocardial injury, respectively. All-cause death was higher among patients with type 2 MI (62.5%) and injury (72.4%) compared to type 1 MI (36.7%). Unadjusted rates of MACE were similar between type 1 and type 2 MI. History of coronary heart disease was an independent predictor of MACE in patients with type 2 MI and injury.

Conclusions:

Patients with type 2 MI and injury have higher noncardiac mortality and similar unadjusted rates of nonfatal MI and cardiac death. Subsets of patients with type 2 MI or injury with coronary heart disease may benefit from targeted therapies to lower rates of cardiac events.

Perspective:

Approximately two-thirds of patients with type 2 MI or myocardial injury die within 5 years, with the majority of deaths being secondary to noncardiac causes. This population is also at higher risk of cardiac events at long-term follow-up. History of coronary artery disease among patients with type 2 MI may identify those who would benefit from further risk stratification and/or aggressive secondary prevention therapies.

Keywords: Acute Coronary Syndrome, Coronary Disease, Myocardial Infarction, Myocardial Ischemia, Outcome Assessment, Health Care, Risk, Secondary Prevention, Tertiary Healthcare, Troponin I


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