The sooner the better? What is the optimal timing for coronary angiography in high-risk non-ST-elevation acute coronary syndrome

Abstract Introduction current guidelines recommend an early invasive coronary angiography (ICA), in the first 24 hours, for high-risk non-ST elevation acute coronary syndrome (NSTE-ACS) patients. However, several studies have failed to demonstrate a significant improvement in all-cause mortality, with controversial results regarding recurrent ischemia and myocardial infarction. Purpose to evaluate the optimal timing of ICA in high-risk NSTE-ACS. Methods this was a national multicentre retrospective study of patients hospitalized for NSTE-ACS between October 2010 and October 2023. Patients presenting in Killip class IV, mechanical complications, life-threatening arrhythmias or cardiac arrest were excluded. Participants were divided into three groups, according to the timing of ICA: in the first 24 hours (D0), between 24 and 48 hours (D1) and between 48 and 72 hours (D2). The incidence of in-hospital complications and mortality, as well as 1-year mortality rate and cardiovascular rehospitalization, was compared for the three groups. Results a total of 9949 patients was included, 98.2% with non-ST elevation myocardial infarction (NSTEMI) and 1.8% with unstable angina with high-risk criteria (GRACE risk score >140 or transient ST-segment elevation). Most patients were submitted to early ICA (46.7%), with 26.7% and 26.6% in D1 and D2, respectively. Interestingly, patients in higher Killip class (II or III) were referred for ICA latter than patients in Killip class I (9.0% in D0 vs. 11.3% in D1 vs. 13.5% in D2, p<0.001). Regarding in-hospital complications, early ICA was associated with a lower incidence of acute heart failure (8.5% vs. 11.1% vs. 11.5%, p<0.001) and shorter length of stay (7 vs. 6 vs. 10 days, p=0.01). However, it did not reduce in-hospital mortality (1.2% vs. 0.7% vs. 0.8%, p=0.07), recurrent myocardial infarction (0.9% vs. 1.5% vs. 1.3%, p=0.09), cardiogenic shock (7.9% vs. 5.7% vs. 5.4%, p=0.19), mechanical complications (0.1% vs. 0.2% vs. 0.1%, p=0.50) or sustained ventricular tachycardia (0.8% vs. 0.6% vs. 0.4%, p=0.12). Left ventricular ejection fraction was also similar between groups (54%±12, p=0.97). There were also no significant differences between groups regarding 1-year mortality or cardiovascular rehospitalization (15.1% vs. 15.9% vs. 15.7%, p=0.89). Conclusion in high-risk NSTE-ACS patients, early ICA resulted in lower incidence of acute heart failure and shorter length of stay. However, timing of ICA didn’t show a significant impact on in-hospital mortality or complications, nor in 1-year mortality rate or cardiovascular rehospitalization.