Late Mortality After Myocardial Injury in Critical Care Non-Cardiac Surgery Patients Using Machine Learning Analysis

Myocardial injury after noncardiac surgery (MINS) increases mortality within 30 days. We aimed to evaluate the long-term impact of myocardial injury in a large cohort of patients admitted to intensive care after noncardiac surgery. All patients who stayed, at least, overnight with measurement of high-sensitive cardiac troponin were included. Clini-cal characteristics and occurrence of MINS were assessed between patients who died and survivors using chi-square test and Student t test. Variables with p <0.01 in the univariate model were included in the Cox regression model to identify predictor variables. Survival decision tree (SDT), a machine learning model, was also used to find the predictors and their correlations. We included 2,230 patients with mean age of 63.8 +/- 16.3 years, with most (55.6%) being women. The prevalence of MINS was 9.4% (209 patients) and there were 556 deaths (24.9%) in a median follow-up of 6.7 years. Univariate analysis showed variables associated with late mortality, namely: MINS, arterial hypertension, previous myocardial infarction, atrial fibrillation, dementia, urgent surgery, peripheral artery dis-ease (PAD), chronic health status, and age. These variables were included in the Cox regression model and SDT. The predictor variables of all-cause death were MINS (hazard ratio [HR] 2.21; 95% confidence interval [CI] 1.77 to 2.76), previous myocardial infarction (HR 1.47; 95% CI 1.14 to 1.89); urgent surgery (HR 1.24; 95% CI 1.01 to 1.52), PAD (HR 1.83; 95% CI 1.23 to 2.73), dementia (HR 2.54; 95% CI 1.86 to 3.46) and age (HR 1.05; 95% CI 1.04 to 1.06). SDT had the same predictors, except PAD. In conclusion, increased high-sensitive troponin levels in patients who underwent noncardiac surgery raised the risk of short and late mortality. (c) 2023 Elsevier Inc. All rights reserved. (Am J Cardiol 2023;204:70-76)