Timing of coronary angiography in patients with non-ST-elevation acute coronary syndrome: long-term clinical outcomes from the nationwide SWEDEHEART registry

Background: Current guidelines stress the importance of early invasive assessment of patients with non -ST-elevation acute coronary syndrome (NSTE-ACS), in particular those at high risk. However, supporting scientific evidence is limited. Aims: We aimed to investigate the prognostic impact of the timing of coronary angiography in a large cohort of NSTE-ACS patients. Methods: We performed a retrospective analysis including 34,666 NSTE-ACS patients registered from 2013 to 2018 in the SWEDEHEART registry. The prognostic implications of the timing of coronary angi-ography on a continuous scale and within <24 vs 24-72 hours were assessed using Cox regression analyses. Results: The median time interval from admission to invasive assessment was 32.8 (25th, 75th percentiles 20.4-63.8) hours. There was no apparent time window within 96 hours from admission that provided prog-nostic benefit. Coronary angiography within 24-72 hours (vs <24 hours) was not associated with worse out-come overall (all-cause mortality: hazard ratio 1.01, 95% confidence interval [CI] 0.92-1.11; major adverse events: hazard ratio 1.04, 95% CI: 0.98-1.12). Interaction analyses indicated a greater relative benefit of coronary angiography <24 hours in some lower-risk groups (women, non-diabetics, patients with minor tro-ponin elevation) but neutral effects in higher-risk groups (defined by age or the GRACE 2.0 score). Conclusions: These Swedish data do not provide support for an early invasive strategy in NSTE-ACS, especially in high-risk patients. Our results suggest that the timing of invasive assessment should rather be based on individualised decisions integrating symptoms and risk panorama than on strictly defined time intervals.