The clinical features and prognosis of type 4C myocardial infarction in patients with non-ST-segment elevation myocardial infarction

BACKGROUND: Type 4C myocardial infarction (MI) is a special type of myocardial infarction related to restenosis without thrombosis. There is a lack of relevant data on this new classification of acute MI (AMI). This study set out to examine the prognosis and treatment of type 4C MI in patients with non-ST-segment elevation MI (NSTEMI). METHODS: With reference to the NSTEMI cohort study database, we enrolled 1,032 cases of type 1 MI and 42 cases of type 4C MI from the period January 01, 2018 to August 31, 2018. All cases were followed up for 1 year. The outcome was major cardiovascular adverse events (including all-cause deaths, nonfatal MI, heart failure necessitating hospitalization, uncontrollable angina pectoris, and revascularization of the target vessels). Risk ratios (RR) were calculated using the generalized linear model. Cox multivariate analysis was performed to analyze the prognostic effects of drug-coated balloon (DCB) angioplasty or drug-eluting stent (DES) implantation in patients with type 4C MI. RESULTS: Compared with type 1 MI, type 4C MI was associated with a higher incidence of major adverse cardiovascular events (MACEs) [21.43% vs. 5.14%; adjusted RR: 3.725, 95% confidence interval (CI): 1.937–7.164]. Type 4C MI also showed a higher 1-year mortality rate than type 1 MI (7.14% vs. 1.55%; unadjusted RR: 4.607, 95% CI: 1.395–15.212). However, after adjusting for covariates, no statistical difference was noted (adjusted RR: 2.515, 95% CI: 0.768–8.233). Multiple adjustments to the Cox multivariate models revealed that neither DCB nor DES affected the clinical outcomes. CONCLUSIONS: Type 4C MI has a poorer prognosis than type 1 MI. DCB angioplasty and DES implantation show similar efficacy in the treatment of type 4C MI.