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.