Lifelong Treatment With Clopidogrel Should Be Given After DES Implantation

摘要

Coronary stent thrombosis (ST) is an uncommon and potentially catastrophic complication of percutaneous coronary intervention (PCI) (1). The importance of potent dual antiplatelet therapy (DAT) with aspirin and a thienopyidine (usually clopidogrel) for prevention of ST is well-established (2). Aspirin blocks the thromboxane pathway of platelet activation while clopidogrel, which bind to the P_2Y_(12) platelet membrane receptor, blocks the adenosine diphosphate pathway of platelet activation. Bare-metal stent (BMS) thrombosis occurs in <1% of the cases, usually within the first month after PCI. Dual antiplatelet therapy was initially recommended for 1 month following BMS implantation. The advent of drug-eluting stents (DES) has raised concerns regarding later occurrence of ST, beyond the traditional 1 -month timeframe, especially in complex lesion subsets that were excluded from randomized trials that compared BMS to DES. Initially DAT was recommended for 3-6 months following DES implantation, however this period was later extended out to 1 year (3). Premature cessation of clopidogrel therapy is the most important risk factor for DES thrombosis (4). Studies have suggested an 0.6% annual thrombosis risk with DES beyond the first year post PCI (5). Animal and human studies have demonstrated a persistent peri-stent inflammatory response and incomplete vessel wall healing, which appear to be the pathological substrate underlying this phenomenon (6, 7). These findings have prompted many physicians to prescribe DAT indefinitely in order to prevent ST.