Clinical outcomes and need for intensive care after non-ST-segment-elevation myocardial infarction

Background: The decision on whether non-ST-segment elevation myocardial infarction (NSTEMI) patients should be admitted to intensive care units (ICU) takes into account several factors including hospital routines. The Acute Coronary Treatment and Intervention Outcomes Network (ACTION) ICU score was developed to predict complications requiring ICU care post-NSTEMI.

Methods: We described patient characteristics and clinical outcomes of 1263 NSTEMI patients admitted to a private hospital in Sao Paulo, Brazil, from 2014 to 2018. We also aimed to retrospectively identify NSTEMI patients who might not have needed to be admitted to the ICU based on the ACTION ICU risk score. We defined complications requiring ICU care post-NSTEMI as cardiac arrest, cardiogenic shock, stroke, re-infarction, death, heart block requiring pacemaker placement, respiratory failure, or sepsis.

Results: Mean age was 62.3 years and 35.8% were female. A total of 94.6% of NSTEMI patients were admitted to the ICU. Most NSTEMI patients (91.9%) underwent coronary angiography. Percutaneous coronary intervention was performed in 47.1% and coronary artery bypass graft surgery in 10.3%. Complications requiring ICU care occurred in 62 patients (4.9%). In-hospital mortality rate was 1.3%. Overall, 70.4% had an ACTION ICU score ≤ 5. The C-statistics for the ACTION risk score to predict complications was 0.55 (95% confidence interval 0.47-0.63).

Conclusions: Complications requiring ICU care were infrequent in a cohort of NSTEMI patients who were routinely admitted to the ICU over a 4-year period. The ACTION risk score had low accuracy in the prediction of complications requiring ICU care in our population.