Identification of Low- Versus High-Risk Acute Coronary Syndrome for a Selective ECG Monitoring Strategy

Background: While admission of patients with acute coronary syndromes (ACS) in cardiology intensive care unit (CICU) is usual, in-hospital major outcomes in lower risk patients may be evaluated after early coronary angiography according to the European guidelines. Methods: Consecutive ACS patients were prospectively included after coronary angiography evaluation within 24 h and percutaneous coronary intervention (PCI), when required. Patients were classified as high- or low-risk according to hemodynamics, rhythmic state, ischemic and bleeding risks. Major in-hospital outcomes were assessed. Results: From January to June 2021, 277 patients were enrolled (62.8% with ST-segment elevation myocardial infarction (STEMI) (n = 174); 37.2% with non-NSTEMI (NSTEMI) (n = 103). PCI was required for 260 patients (93.9%). Seventy-four patients (26.7%) were classified as low-risk (n = 47 NSTEMI; n= 27 STEMI) and 203 patients (73.3%) as high-risk of events. All patients were monitored in CICU. While 38 patients (18.7%) from the high-risk group reached the primary endpoint, mainly related to rhythmic or conduction disorder (n = 24, 11.8%) or unstable hemodynamics (n = 17; 8.4%), only 1 patient (1.3%) in the low-risk group had one major outcome (no fatal bleeding); p < 0.01. The negative predictive value of our patient stratification for the absence of major in-hospital outcome was 100% (CI95%: 100–100%) for STEMI and 97.9% CI95%: 93.2–100% for NSTEMI patients. Conclusions: Stratification of ACS patients after early coronary angiography and most of the time PCI, identify a population with very low risk of in-hospital events (1/4 of all ACS and 1/2 of NSTEMI) who may probably not require ECG monitoring and/or CICU admission. (NCT04378504).