ObjectiveCurrent guidelines recommend that patients with non-ST elevation acute coronary syndromes (NSTEACS) receive dual antiplatelet therapy (DAPT) early in hospitalisations. However, observational studies suggest that this rarely occurs. We evaluated site-specific variation and clinical outcomes associated with early DAPT among patients undergoing angiography for NSTEACS.MethodsIn this observational analysis, we identified patients undergoing angiography for NSTEACS in Veterans Affairs hospitals from 2008 to 2016 and assessed characteristics and site variation associated with early DAPT (administration <24 hours of admission). Using propensity matching, we compared time to revascularisation, recurrent myocardial infarction (MI) and mortality between those receiving early DAPT and those not receiving early DAPT (administration ≥24 hours).ResultsOf 45 569 patients undergoing angiography for NSTEACS, 15 084 (33%) received early DAPT. Early DAPT was more frequent in patients with non-ST elevation MI, prior surgical revascularisation and among patients undergoing revascularisation. There was a greater than twofold difference in early DAPT across sites, independent of patient characteristics (median OR 2.43, 95% CI 2.28 to 2.55). There was no difference in time topercutaneous coronary intervention (PCI) between groups, but a significant delay to surgical revascularisation with early DAPT (median 4 vs 3 days, p<0.001) without reduction in hazard of death or MI (HR 1.08, 95% CI 1.00 to 1.16) and similar results demonstrated in the subgroup of patients undergoing revascularisation (HR 1.02, 95% CI 0.91 to 1.13).ConclusionAmong NSTEACS patients undergoing coronary angiography, early DAPT was not associated with improvement of outcomes but was associated with delays in surgical revascularisation.