Background: While type 1 MI is caused by plaque rupture leading to an acute atherothrombotic coronary event, type 2 MI is defined by an evidence of ischemia, where a condition other than coronary artery disease leads to  a mismatch in myocardial oxygen supply and demand. The evidence regarding the prognosis of patients with type 2 myocardial infarction is ambiguous. While some studies demonstrated higher mortality rates in patients with type 2 MI compared to type 1 MI, other trials revealed comparable mortality rates after multivariate adjustment.

Purpose: The aim of the present analysis was to compare the long-term survival of patients without MI with patients, which presented with type 1 and type 2 MI.

Methods: The present analysis is a longitudinal registry analysis based on the Essen Registry of Coronary Artery Disease (ECAD registry) of patients undergoing coronary angiography at the West German Heart and Vascular Center, Department of Cardiology and Vascular Medicine, at the University Hospital Essen between 2004 and 2019. Type 1 MI was defined as a significant troponin level (Siemens Troponin I (Dimension) >0,1 ng/ml and Troponin I Ultra (Centaur) >40 ng/l) and coronary stenosis requiring intervention. Type 2 MI was defined as a significant troponin increase without percutaneous coronary intervention. During follow up, the all-cause mortality of patients without MI and patients with type 1 and 2 MI was investigated. Cox regression analysis was used to determine the association of type 1 and 2 MI with all-cause mortality. Multivariable adjustment was performed for age, sex, low-density lipoprotein cholesterol, systolic blood pressure, diabetes, family history of premature coronary artery disease and nicotine abuse.

Results: Overall, data from 18,286 coronary angiography exams (mean age 65.3 ± 13.0 years, 71.6% male) were included in our analysis. 14,883 patients (81.3%) had no MI, 1,699 patients (9.3%) presented with type 1 MI and 1,704 patients (9.3%) presented with type 2 MI. During a mean follow-up of 3.4 ± 3.6 years, 3321 deaths occurred (18.2%). Mortality rates were higher in patients with type 1 MI (25.2%) and type 2 MI (29.1%) as compared to patients without MI (16.1%) (Type 1 MI vs. without MI: p<0.0001, type 2 MI vs. without MI: p<0,0001). In Cox multivariable adjusted regression analysis, Type 1 MI (Hazard ratio [standard deviation]: 1.42 [1.14-1.76], p=0.0015) and type 2 MI (2.326 [1.91-2.84], p= <0.0001) were significantly associated with an increased all-cause mortality compared to patients without MI. Kaplan-Meier analysis confirmed the lowest survival rates for patients with type 2 MI (Figure 1).

Conclusion: In this large longitudinal registry cohort of patients undergoing invasive coronary angiography, type 2 MI was associated with impaired long-term survival. Prospective studies are required to determine risk stratification for these high-risk populations.

Figure 1: Kaplan-Meier Survival Estimates for the survival probability of patients without myocardial infarction, with type 1 and 2 myocardial infarction.