Standard versus extended dual antiplatelet therapy after pci in acute coronary syndrome: a systematic review and meta-analysis

Background Acute coronary syndrome (ACS) remains a major cause of cardiovascular morbidity and mortality worldwide. Following percutaneous coronary intervention (PCI), dual antiplatelet therapy (DAPT) is routinely prescribed to prevent recurrent ischaemic events and stent thrombosis. Although guidelines generally recommend 12 months of therapy, the benefit of extending DAPT beyond one year remains uncertain because potential reductions in ischaemic events must be balanced against bleeding risk. Purpose To compare the efficacy and safety of standard-duration (≤12 months) versus extended-duration (>12 months) DAPT after PCI in adults with ACS. Methods A systematic search of PubMed, Embase, and the Cochrane Library (inception-November 2025) identified randomised and comparative observational studies enrolling adults with ACS treated with PCI using any stent type. Studies directly comparing standard duration versus extended duration DAPT were included. Primary outcomes were myocardial infarction and clinically relevant bleeding (BARC-defined events). Secondary outcomes included mortality, major adverse cardiovascular events (MACE), stroke, target-vessel revascularisation (TVR), and definite stent thrombosis. Pooled risk ratios were calculated using random-effects models. Results Fourteen studies (13 cohort studies and 1 randomised trial), including 69,087 patients, were analysed. During overall follow-up, extended DAPT did not reduce myocardial infarction (RR 0.97, 95% CI 0.57–1.65), MACE (RR 0.82, 95% CI 0.52–1.31), stroke (RR 1.16, 95% CI 0.85–1.60) or definite stent thrombosis (RR 0.66, 95% CI 0.20–2.21). All-cause mortality was higher with extended therapy (RR 2.47, 95% CI 1.61–3.80). Target-vessel revascularisation was lower with standard-duration DAPT (RR 0.52, 95% CI 0.30–0.89). Bleeding risk was similar between strategies, both for any bleeding (RR 0.96, 95% CI 0.72–1.28) and clinically relevant bleeding (BARC 2/3/5 RR 1.07, 95% CI 0.78–1.49). In a landmark analysis at 12 months, extended DAPT did not reduce myocardial infarction (RR 0.57, 95% CI 0.12–2.62), MACE (RR 0.65, 95% CI 0.25–1.68), definite stent thrombosis (RR 0.55, 95% CI 0.11–2.79), cardiac death (RR 2.24, 95% CI 1.00–5.00) or all-cause mortality (RR 1.85, 95% CI 0.68–5.03), nor increase clinically relevant bleeding (BARC 2/3/5 RR 0.98, 95% CI 0.55–1.77). Conclusions In patients with ACS undergoing PCI, extending dual antiplatelet therapy beyond 12 months does not provide consistent reductions in major ischaemic outcomes, including myocardial infarction, stent thrombosis, or mortality. The absence of benefit was confirmed both during overall follow-up and in landmark 12-month analyses, with a reduction observed only in repeat revascularisation, a softer endpoint. These findings support an individualised approach to DAPT duration rather than routine prolongation beyond one year. Further adequately powered randomised trials are needed.