Current guidelines recommend that patients be given dual antiplatelet therapy (DAPT; combination of a P2Y12 inhibitor [clopidogrel, prasugrel, or ticagrelor] with acetylsalicylic acid [ASA]) ranging from six months to 12 months following percutaneous coronary intervention (PCI) with stenting, with the aim of preventing stent thrombosis and major adverse cardiac and cerebrovascular events (MACCEs). However, debate is ongoing about the optimal duration of DAPT; importantly, patient characteristics may be an important factor in treatment duration decisions. In some settings, DAPT for even less than six months may be appropriate (e.g., patients with high risk of bleeding), while other patients may derive greater benefit from extended DAPT (e.g., patients with high risk of stent thrombosis and low risk of bleeding). Previous reviews have reported an increased risk of death among patients who received DAPT for more than 12 months following PCI with stenting, but whether this risk is common across all patient subgroups is unclear.
Previous systematic reviews (SRs) have attempted to determine the optimal duration of DAPT; however, there is a paucity of data on the impact of specific patient characteristics or type of P2Y12 inhibitor on the effect estimate. One SR reported that extending DAPT beyond 12 months reduced the risk of stent thrombosis in patients without, but not with, acute coronary syndrome (ACS); however, no significant differences were reported in the risk of cardiovascular (CV) death or myocardial infarction (MI). A recent network metaanalysis (NMA) found that among patients randomized to ticagrelor, prasugrel, or clopidogrel, the risk of major adverse cardiac events and MI were lower with both ticagrelor and prasugrel compared with clopidogrel. Shah et al. reported a reduced risk of all-cause and CV death among patients randomized to ticagrelor compared with clopidogrel; however, whether these results are consistent at all durations of DAPT is unknown.
To make appropriate decisions, clinicians require a transparent and comprehensive review of the evidence to evaluate the potential benefits and harms associated with extending DAPT beyond 12 months after stenting to potentially personalize therapy and reach best patient outcomes. Such information may also inform P2Y12 inhibitor reimbursement policies by insurers because such policies may be limited to 12 months, in particular in the public sector. In this study, we will evaluate the comparative clinical effectiveness of different DAPT durations by performing an SR to assess the benefits and harms associated with extending DAPT beyond 12 months following PCI with stenting. We will also investigate the effect of extended DAPT in clinically relevant patient subgroups, including age, history of MI, ACS at presentation, diabetes, and smoking status, and the impact of individual P2Y12 inhibitors. Of note, the patient subgroups were selected based on the clinical components of the DAPT Score combined with consideration of findings from a recent clinical review that found different effects between shorter and longer DAPT duration for some subgroups; the selected subgroups were chosen because statistically significant differences were observed in key clinical outcomes when extended DAPT was used. In addition, we will evaluate the comparative cost-effectiveness of different DAPT durations; results from the clinical review will be used to inform clinical input for the economic evaluation.
Funding: CADTH receives funding from Canada’s federal, provincial, and territorial governments, with the exception of Quebec.
Suggested citation:
Dual antiplatelet therapy following percutaneous coronary intervention: clinical and economic impact of standard versus extended duration — project protocol. Ottawa: CADTH; 2018 Feb.
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