Type 2 myocardial infarction among critically ill elderly patients in the Intensive Care Unit: the clinical features and in-hospital prognosis.

BACKGROUND: Type 2 myocardial infarction (T2MI) refers to myocardial ischemic necrosis as a result of myocardial oxygen supply/demand mismatch, which are common comorbidities of critically ill patients. The purpose of this study was to investigate the incidence rate and risks of T2MI in critically ill elderly patients and further elucidate in-hospital prognostic factors.

METHODS: A total of 223 critically ill elderly patients admitted to our hospital from October 2016 to September 2018 were recruited. The clinical data and the in-hospital mortality rate were compared between the T2MI and non-T2MI groups. Multivariate linear regression analysis was used to identify independent factors related to T2MI. The clinical data and incidence of T2MI were also compared between patients who survived and those who died; multivariate regression analysis was used to identify independent risk factors for in-hospital death and survival analysis was conducted.

RESULTS: In this study, the incidence of T2MI was 24.2% (54/223), and the mortality rate of critically ill elderly patients was 39.0% (87/223). Multivariate linear regression analysis showed that severe hypoxemia, arrhythmia, shock, and multiple organ dysfunction syndrome (MODS) were independent risk factors of T2MI. Compared to the survival patients, the use of mechanical ventilation, the incidence of T2MI, APACHE II score, troponin T, high-sensitivity C-reactive protein, and procalcitonin levels were significantly higher in patients who died, while the estimated glomerular filtration rate (eGFR) was significantly decreased (all P < 0.05). In-hospital mortality was significantly increased in patients with T2MI (59.3% vs. 32.5%, P < 0.001). After adjustment for relevant factors, the incidence of T2MI, mechanical ventilation required, and eGFR reduction were independent and significant predictors of in-hospital death.

CONCLUSIONS: Critically, ill elderly patients have a high incidence of T2MI. In addition to severe hypoxia, shock, and arrhythmia, MODS is also associated with T2MI. At the same time, the risk of in-hospital death is increased in patients with type 2 MI.