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.