Early coronary angiography in NSTEMI: a regional Victorian perspective

Background: Current guidelines highlight a paucity of evidence guiding optimal timing for non-ST-elevation myocardial infarction (NSTEMI) in high-risk and non-high-risk cases. Aim: We assessed long-term major adverse cardiovascular events (MACEs) in NSTEMI patients undergoing early (<24 h) versus delayed (>24 h) coronary angiography at 6 years. Secondary end-points included all-cause mortality and cumulative MACE outcomes. Methods: Baseline characteristics and clinical outcomes were assessed among 355 patients presenting to a tertiary regional hospital between 2017 and 2018. Cox proportional hazard models were generated for MACE and all-cause mortality outcomes, adjusting for the Global Registry of Acute Coronary Events (GRACE) score, patient demographics, biomarkers and comorbidities. Results: Two hundred and seventy patients were included; 147 (54.4%) and 123 (45.6%) underwent early and delayed coronary angiography respectively. Median time to coronary angiography was 13.3 and 45.4 h respectively. At 6 years, 103 patients (38.1%) experienced MACE; 41 in the early group and 62 in the delayed group (hazard ratio (HR) = 2.23; 95% confidence interval (CI) = 1.50–3.31). After multivariable adjustment, the delayed group had higher rates of MACE (HR = 1.79; 95% CI = 1.19–2.70), all-cause mortality (HR = 2.76; 95% CI = 1.36–5.63) and cumulative MACE (incidence rate ratio = 1.54; 95% CI = 1.12–2.11). Subgroup analysis of MACE outcomes in rural and weekend NSTEMI presentations was not significant between early and delayed coronary angiography (HR = 1.49; 95% CI = 0.83–2.62). Conclusion: Higher MACE rates in the delayed intervention group suggest further investigation is needed. Randomised control trials would be well suited to assess the role of early invasive intervention across all NSTEMI risk groups.