Type 2 myocardial infarction: A descriptive analysis and comparison with type 1 myocardial infarction.

BACKGROUND

While 'plaque rupture' is the paradigm of type 1 myocardial infarction (T1MI), T2MI is myocardial necrosis secondary to oxygen supply-demand mismatch. Being a heterogeneous and rather newly defined group, data are lacking about T2MI.

METHODS

A retrospective review of medical records of patients diagnosed with T2MI in the Rabin Cardiology Center, Israel between the years 2007 and 2012 was performed. Following a descriptive analysis, we used multivariate time dependent models to estimate the association of T2MI with the risk for 30-day, 1-year, and 5-year all-cause-mortality and major adverse cardiovascular events (MACE), and compared it to a T1MI group matched for age, gender and electrocardiographic changes.

RESULTS

The study included 107 T2MI (and 107 T1MI) patients. Sepsis, anemia, and atrial fibrillation were the most common etiologies. Triple anti-thrombotic therapy was given to 22% of T2MI patients (vs. 82% of T1MI patients, p<0.001). Twenty-five percent were managed using urgent percutaneous coronary intervention. Angiography unmasked acute plaque rupture in 29% of T2MI patients group. Compared to T1MI, T2MI was associated with higher all-cause-mortality rate: adjusted-hazard-ratio 7.14 (1.31-38.9) at 30 days, 3.42 (1.51-7.75) at 1 year, and 2.08 (1.14-3.81) at 5 years follow-up. MACE risk was consistent between T2 and T1MI patients.

CONCLUSIONS

The most common T2MI triggers are sepsis, anemia, and atrial fibrillation. Compared to a T1MI population, T2MI is associated with higher short- and long-term mortality rates but equal cardiovascular mortality and MACE risk. As many as 30% may harbor plaque rupture and in fact have T1MI.