Comparison of in-hospital and long-term mortality and assessment of their predictors in patients with myocardial infarction and unstable angina

Background: The extent of myocardial damage largely determines both in-hospital and long-term mortality in patients with acute coronary syndrome. According to the literature, the in-hospital and long-term mortality rates in patients with unstable angina (UA) are lower than those in the patients with myocardial infarction (MI). Aim: To evaluate the in-hospital and long-term mortality rates and their predictors in patients undergoing in-patient treatment for acute coronary syndrome (MI and UA) in the regional cardiovascular center with the service territory of 1 million persons. Materials and methods: This retrospective registry study enrolled 1130 patients (715 [63.3%] men, 415 [36.7%] women) who were treated for UA and MI in the regional cardiovascular center in 2019. Based on the discharge diagnosis, the patients were divided into two groups: patients with MI (n = 766) and those with an UA episode (n = 364). The in-hospital and delayed mortality rates, as well as their predictors, were analyzed in both groups. The mean duration of the follow-up was 17.8 3.6 months. Results: The in-hospital mortality in patients with confirmed MI was 11.1% (85 patients) versus 0.27% (1 patient) in the UA patients (p 0.001). The independent predictors of in-hospital mortality in MI patients were a decreased left ventricular ejection fraction (LV EF) (odds ratio (OR) 0.9021, 95% confidence interval (CI) 0.82090.9914, p = 0.0324), chronic kidney disease C3a and above (OR 9.3205, 95% CI 2.670632.5283, p = 0.0005), and the extension of coronary involvement at coronary angiography (OR 1.3526, 95% CI 1.06670.0127, p = 0.0127). The long-term mortality in MI patients was 10.4% (72 patients) with no significant difference from that in UA patients (9.9%, 36 patients, p = 0.76). The independent predictors of long-term mortality after MI were older age (OR 1.12, 95% CI 1.011.22, p = 0.0052), chronic kidney disease C3a and above (OR 2.3375, 95% CI 1.13924.7963, p = 0.0206), decreased EF (OR 0.8895, 95% CI 0.730.99, p = 0.0364), atrial fibrillation on admission (OR 3.1462, 95% CI 1.35107.3268, p = 0.0079), and diabetes mellitus (OR 2.3163, 95% CI 1.25524.2744, p = 0.0072). In the UA patients, the predictors of the long-term mortality were a decrease in LV EF (OR 0.9139, 95% CI 0.86830.9619, p = 0.0006) and in blood hemoglobin level (OR 0.9729, 95% CI 0.95440.9917, p = 0.0050). Conclusion: The in-hospital mortality in UA patients is lower than that in MI patients, with comparable long-term mortality. This indicates the need of active follow-up of the patients with past UA, irrespective of the endovascular assessment and intervention.