Timing of Early Invasive Intervention in Patients with Moderate to High Risk Acute Coronary Syndromes

BACKGROUND: Although international guidelines recommend an early invasive intervention for the treatment of patients presenting with acute coronary syndrome (ACS), the optimal timing of this intervention remains uncertain. We aimed to determine the best time period for an early invasive intervention in ACS patients. METHODS: Literature searches for controlled trials on ACS (1970-Sep. 2010) were conducted. Patients with moderate to high risk of ACS sent to the catheterization laboratory within 72 hours of admission/symptom onset were analyzed. The major outcome was the rate of death or recurrent myocardial infarction (re-MI). RESULTS: A total of 10 trials with 39,453 patients were eligible. Intervention performed within 24-48 hours was associated with a significantly lower death or re-MI rate compared with intervention after 48 hours (odds ratio [OR] 0.64; 95% confidence interval [CI] 0.52-0.79; P < 0.0001). Death or re-MI was also reduced in the 12-24 hour group relative to the 24-48 hour group (8.4% vs. 10.8%; OR 0.85; 95% CI 0.75-0.97; P = 0.01). Performing angiography within <12 hours provided no benefit over 12-24 hours (P > 0.05). Interestingly, intervention before 3 hours was associated with a higher rate of death or re-MI compared with intervention within 3-48 hours (P = 0.0008). CONCLUSIONS: Intervention following ACS should be undertaken within 24 hours; however, immediate (<3 hours) angiography does not provide any benefit and may even be harmful.