Volume 29, Issue 166, December 2025

Outcomes of early versus delayed intervention in emergency department patients with non-ST elevation acute coronary syndrome: a systematic review

Mazi Mohammed Alanazi¹, Raghad Mohammed Ghabban², Mohammed Obaid Alharbi³

¹Saudi and Jordanian Board Emergency Medicine, Emergency Department, Head of Emergency Research Unit, First Health Cluster, Riyadh, Saudi Arabia
²Saudi Board Emergency Medicine Resident, Emergency Department, Prince Mohammed Bin Abdulaziz hospital, Riyadh Saudi Arabia
³Saudi Board Emergency Medicine Resident, Emergency Department, King Abdulaziz Medical City, Riyadh, Saudi Arabia

ABSTRACT

Background: For non-ST elevation acute coronary syndrome (NSTE ACS), guidelines endorse an invasive strategy, but the optimal timing (immediate, early, or delayed) is debated, especially for emergency department (ED) pathways. We aimed to synthesize studies comparing early versus delayed invasive management in NSTE ACS, focusing on clinically relevant outcomes overall and within risk strata. Method: MEDLINE, PubMed, Embase, Cochrane CENTRAL, Web of Science, and Scopus (inception to 2025); ClinicalTrials.gov, WHO ICTRP; reference lists and forward citation tracking. Dual independent screening, data extraction with a piloted form, and PRISMA-aligned reporting. Risk of bias was assessed with RoB 2 (trials) and ROBINS I (cohorts). Owing to heterogeneity in timing cut-offs, therapies, and endpoints, a structured qualitative synthesis was performed. Results: In trials, routine immediate invasive management did not reduce major clinical events versus delayed approaches in unselected patients. Signals consistently favored earlier angiography among high-risk subgroups, particularly GRACE scores more than 140 and those with heart failure, while an isolated trial showed the benefit of immediate intervention. Observational data aligned with neutral overall effects but associated earlier procedures (within 24 to 48 h) with improved outcomes in higher risk patients. Major bleeding and procedural complications were generally similar between timing strategies. Conclusions: For ED care, a risk tailored approach is supported: immediate invasive management for very high risk features; early (less than 24 h) for high risk patients; and angiography within 24 to 72 h appears safe for stabilized intermediate risk patients.

Keywords: NSTE ACS; early invasive strategy; delayed invasive strategy; coronary angiography; percutaneous coronary intervention; time to treatment; risk stratification; GRACE risk score; emergency department; systematic review

Medical Science, 2025, 29, e231ms3753

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DOI: https://doi.org/10.54905/disssi.v29i166.e231ms3753

Published: 23 December 2025