Usefulness of the ACTIO N ICU score to predict complications requiring critical care in Mexican patients with non-ST-segment elevation myocardial infarction

José M. Alanís-Naranjo, Department of Cardiology, Hospital Regional 1° de Octubre, ISSSTE, Mexico City, Mexico
Agustín Vela-Huerta, Department of Cardiology, Hospital Regional 1° de Octubre, ISSSTE, Mexico City, Mexico
Julio C. Rivera-Hermosillo, Department of Cardiology, Hospital Regional 1° de Octubre, ISSSTE, Mexico City, Mexico
José E. Villegas-Mayoral, Coronary Care Unit, Hospital Regional 1° de Octubre, ISSSTE, Mexico City, Mexico

Objective: The Acute Coronary Treatment and Intervention Outcomes Network Intensive Care Unit (ACTION ICU) score is a tool for assessing the risk of complications associated with non-ST-segment elevation myocardial infarction (NSTEMI) requiring intensive care unit (ICU) admission. The study aimed to describe the usefulness of the ACTION ICU score in Mexican patients with NSTEMI. Methods: A single-center, retrospective, observational, and comparative study of patients with NSTEMI admitted between January 2017 and December 2023; patients with respiratory failure, cardiac arrest, shock, and arrhythmias requiring a pacemaker on admission were excluded from the study. Based on the collected data, the ACTION ICU score was applied to all patients. The cutoff score for ICU admission is 5, with a 9.3% risk of complications. During hospitalization, the composite primary outcome included cardiac arrest, shock, heart block requiring a pacemaker, respiratory failure, stroke, or death. The score’s performance was determined by calculating the area under the curve (AUC). Results: A total of 345 NSTEMI patients were included; 41 (14.2%) developed the primary outcome. The most common complications were shock (12.5%) and respiratory failure (8.1%). A score of 0 to 5 points was present in 187 patients (54.2%), 10 of whom (5.3%) developed the primary outcome. The score had an AUC of 0.77 [CI 0.64-0.97, p value 0.01]. Conclusions: The ACTION ICU score showed acceptable discriminative ability for identifying patients with NSTEMI who need ICU care, providing a valuable tool to predict complications and implement best practices in medical units with limited resources.

Keywords: Non-ST-segment elevation myocardial infarction. ACTION ICU. Acute coronary syndrome. Coronary care unit. Intensive care unit. Complications.