The potential for in-stent restenosis has been reduced considerably by the advent of drug-eluting stent (DES) technology. Unfortunately, the problem of stent thrombosis remains and there are concerns that manipulation of the healing processes after stent implantation may prolong the period of occlusive/thrombotic risk. Although there is uncertainty about the magnitude of the problem, current estimates from registry data suggest an excess risk of up to 0.5–1.0% a year with “off-label” use of DES.1 Stent thrombosis may be catastrophic and fatal in up to 45% cases, and premature discontinuation of dual antiplatelet therapy is one of the most important predisposing factors.2 3 For these reasons recent recommendations state that dual antiplatelet therapy with aspirin and clopidogrel should be prolonged for a minimum of 1 year after DES implantation.4

An increasing number of patients presenting for percutaneous revascularisation are taking oral anticoagulation, usually warfarin. There are no randomised data to guide patient management in this circumstance. Adding aspirin and clopidogrel to warfarin may minimise the risk of stent thrombosis but this may be at the expense of an unacceptable risk of haemorrhagic complications. Conversely, stopping warfarin for up to a year and relying on dual antiplatelet therapy may not be sufficient to prevent the risk of disabling or fatal stroke. Therefore the dilemma when managing these patients is a fine balance between the risks of in-stent restenosis, stent thrombosis, thromboembolism and bleeding complications.

DUAL ANTIPLATELET THERAPY

Aspirin and clopidogrel are the current optimal treatment for patients undergoing percutaneous coronary intervention (PCI). Although there are many potential pathways for platelet activation, the efficacy of this combination is based on the interruption of positive feedback mechanisms mediated by thromboxane A2 and ADP, which may be synergistic. Dual antiplatelet therapy reduces stent thrombosis by 70% compared with aspirin alone, or aspirin and oral anticoagulation …