['The present study aimed to investigate the association between periprocedural myocardial infarction (PMI), defined by creatine kinase (CK)-MB or troponin I (TNI) level elevations >5 times the 99 th percentile of the upper reference limit (URL) within 48 hr after implantation of a drug-eluting stent (DES), and one-year mortality in patients with coronary bifurcation.', 'PMI is reported to be associated with increased one-year mortality after DES implantation. However, the prevalence and association of PMI with mortality after stenting bifurcation lesions remains unclear.', 'We prospectively followed 1,971 patients with true coronary bifurcations who underwent DES implantation as part of the multicenter DEFINITION study. These patients were grouped into categories based on PMI outcome: Non-PMI, CKMB-PMI, TNI-PMI, and CKMB/TNI-PMI. The primary endpoint was the rate of all-cause mortality at one year.', 'PMI occurred in 11.4% of patients by CKMB criteria and 41.3% of patients by TNI criteria. At one-year follow-up, the mortality rate was 2.3% in the entire patient population. However, mortality was significantly higher in the CKMB-PMI (6.4%) and CKMB/TNI-PMI (6.1%) groups compared to the Non-PMI (1.7%) and TNI-PMI (2.1%) groups (all P < 0.05). A 10-fold increase in TNI levels resulted in similar PMI rate (5.2%) and mortality risk (adjusted HR 2.7, 95% CI 3.0-5.2) as a fivefold increase in CKMB levels.'] Is periprocedural myocardial infarction associated with increased mortality in patients with coronary artery bifurcation lesions after implantation of a drug-eluting stent?