Prognosis of spontaneous myocardial infarction and various definitions of periprocedural myocardial infarction in patients who underwent percutaneous coronary intervention.

BACKGROUND Debate exists on the prognostic significance of spontaneous myocardial infarction (SMI) and periprocedural myocardial infarction (PMI), which could be diagnosed by various definitions. METHODS AND RESULTS A total of 10,724 patients undergoing percutaneous coronary intervention (PCI) were consecutively enrolled and followed up for a median of 2.4 years. We evaluated outcomes of all-cause death, cardiac death, and major adverse cardiovascular events (MACE). Patients were stratified into three groups, including the No MI group, PMI group, and SMI group. PMI was defined based on different diagnostic criteria, including the third and fourth universal myocardial infarction (MI) definitions, the society for cardiovascular angiography and interventions (SCAI) definition, and the independent biomarker definition. Regardless of these definitions, the PMI groups were all associated with a significantly increased MACE risk at one year or 1000 days (all P < 0.05), but not all-cause or cardiac death. The SMI group was associated with a markedly elevated risk of death and MACE, but it showed no significant different risk of MACE to PMI using varying definitions. CONCLUSIONS According to various PMI definitions, PMI and SMI were associated with an increased risk of MACE, but not death for PMI. No significantly different risk of MACE was observed between PMI and SMI.