Platelet activation is central in the vascular response to percutaneous coronary intervention (PCI). In addition, patients with coronary artery disease (CAD), particularly those with an acute coronary syndrome (ACS), have pre-existing platelet hyper-reactivity. Together, these are among the factors that predispose to stent thrombosis (ST). Thus, dual antiplatelet therapy (DAT), which consists of aspirin and a thienopyridine, forms the cornerstone of pharmacotherapy following PCI with the goal of reducing ST, as well as ischaemic events related to the underlying CAD. Adherence to DAT, and the need for a longer duration of treatment, has become even more important for patients receiving drug-eluting stents (DES), as concerns have been raised regarding the increased risk of very late ST (>1 year) with the current generation of stents.1 Table 1 summarises the most recent guidelines on DAT following PCI which have been jointly published by the American College of Cardiology (ACC), American Heart Association (AHA) and Society for Cardiovascular Angiography and Interventions (SCAI).2 3 Despite the routine use of clopidogrel, there is uncertainty about the optimal timing, dose and duration of thienopyridine therapy, and there is a lack of consensus on the management of patients requiring non-cardiac surgery or chronic anticoagulation while being treated with DAT.

ROLE OF PRETREATMENT WITH CLOPIDOGREL

Although current practice in many parts of the world is to administer clopidogrel in the catheterisation laboratory at the time of ad hoc PCI, several clinical trials have evaluated the efficacy of pretreatment (table 2).4^–8 Overall, the data suggest a potential benefit of pretreatment with the 300 mg loading dose, though both PCI-CURE and PCI-CLARITY represent analyses in which the decision to perform PCI was made after randomisation to the two loading strategies. It appears that a 300 mg clopidogrel loading dose needs to be administered at least 6 h prior to …