Optimal timing of an invasive strategy in patients with non-ST-elevation acute coronary syndrome: a meta-analysis of randomised trials

Background A routine invasive strategy is recommended for patients with non-ST-elevation acute coronary syndromes (NSTE-ACS). However, optimal timing of invasive strategy is less clearly defined. Individual clinical trials were underpowered to detect a mortality benefit; we therefore did a meta-analysis to assess the effect of timing on mortality. Methods We identified randomised controlled trials comparing an early versus a delayed invasive strategy in patients presenting with NSTE-ACS by searching MEDLINE, Cochrane Central Register of Controlled Trials, and Embase. We included trials that reported all-cause mortality at least 30 days after in-hospital randomisation and for which the trial investigators agreed to collaborate (ie, providing individual patient data or standardised tabulated data). We pooled hazard ratios (HRs) using random-effects models. This meta-analysis is registered at PROSPERO (CRD42015018988). Findings We included eight trials (n=5324 patients) with a median follow-up of 180 days (IQR 180–360). Overall, there was no significant mortality reduction in the early invasive group compared with the delayed invasive group HR 0·81, 95% CI 0·64–1·03; p=0·0879). In pre-specified analyses of high-risk patients, we found lower mortality with an early invasive strategy in patients with elevated cardiac biomarkers at baseline (HR 0·761, 95% CI 0·581–0·996), diabetes (0·67, 0·45–0·99), a GRACE risk score more than 140 (0·70, 0·52–0·95), and aged 75 years older (0·65, 0·46–0·93), although tests for interaction were inconclusive. Interpretation An early invasive strategy does not reduce mortality compared with a delayed invasive strategy in all patients with NSTE-ACS. However, an early invasive strategy might reduce mortality in high-risk patients. Funding None.