Type 4a myocardial infarction: Incidence, risk factors, and long‐term outcomes

OBJECTIVES: To assess the incidence of and outcomes related to periprocedural (Type 4a) myocardial infarction (MI) in a cohort of patients undergoing percutaneous coronary intervention (PCI) for stable coronary disease or non ST-elevation acute coronary syndrome with stable or falling cardiac troponin levels. BACKGROUND: The 2012 Third Universal Definition for Type 4a MI has not been prospectively studied in routine clinical practice. METHODS: The study included 516 patients undergoing eligible PCI at a single institution. Data were extracted from the National Cardiovascular Data Registry, review of electronic medical records, and telephone interviews. Clinical outcomes assessed at one year included all-cause mortality, recurrent MI, or any repeat coronary revascularization. RESULTS: Based on the Third Universal Definition of MI, 53 (10.3%) patients met criteria for Type 4a MI and 116 (22.5%) had myocardial injury. The Type 4a MI and myocardial injury groups each had significantly higher numbers of stents, longer stent lengths, and more use of rotational atherectomy than the control group. Type 4a MI was not associated with one-year mortality. The composite endpoint of death or recurrent MI at one year was similar between the Type 4a MI and myocardial injury groups (12 vs. 11%; P > 0.05), which were both higher compared with the control group (3%; P = 0.02, 0.03). CONCLUSIONS: Type 4a MI and myocardial injury were frequent, and were associated with more complicated index PCI and more frequent death or recurrent MI at one year as compared with the control group.