Effectiveness and Safety of Single Antiplatelet Therapy Versus Dual Antiplatelet Therapy in Patients with Acute Coronary Syndrome Following Percutaneous Coronary Intervention: A Narrative Review

Abstract

Antiplatelet therapy forms the cornerstone of pharmacological management following percutaneous coronary intervention (PCI) in patients with acute coronary syndrome (ACS). For decades, dual antiplatelet therapy (DAPT) — conventionally comprising aspirin combined with a P2Y12 receptor inhibitor — has represented the standard of care, underpinned by robust evidence demonstrating reductions in major adverse cardiovascular events. However, sustained dual antiplatelet therapy inevitably increases the risk of clinically significant bleeding, which is itself associated with elevated mortality, prolonged hospitalisation, and impaired quality of life. This tension has catalysed growing interest in strategies that involve earlier transition to single antiplatelet therapy (SAPT), thereby reducing haemorrhagic exposure without substantially compromising ischaemic protection. This narrative review evaluates the comparative effectiveness and safety of SAPT versus DAPT in ACS patients following PCI, drawing on evidence from major randomised controlled trials, meta-analyses, and contemporary clinical guidelines. The review examines the pathophysiological rationale for antiplatelet therapy, the pharmacology of relevant agents, the role of risk stratification tools, and the ischaemic and haemorrhagic outcomes associated with abbreviated or single-agent approaches. Evidence from pivotal trials — including TWILIGHT, SMART-CHOICE, STOPDAPT-2, TICO, MASTER DAPT, and HOST-EXAM — is synthesised alongside guideline recommendations from the European Society of Cardiology and the American College of Cardiology/American Heart Association. The available data indicate that, in carefully selected patients — particularly those at elevated haemorrhagic risk — transition to SAPT after one to three months of DAPT can achieve a favourable balance between ischaemic efficacy and bleeding safety. Individual patient characteristics, stent type, clinical presentation, and comorbidities must nonetheless continue to inform clinical decision-making in this nuanced domain. This finding, robust across multiple independent RCTs and confirmed in individual patient data meta-analytic syntheses, represents one of the more substantive advances in post-PCI pharmacotherapy over the past decade.