Gori AM et al. (2008) Incidence and clinical impact of dual nonresponsiveness to aspirin and clopidogrel in patients with drug-eluting stents. J Am Coll Cardiol 52: 734–739

Thrombosis is a complication of drug-eluting stent (DES) implantation, and can occur in patients despite optimum antiplatelet therapy with aspirin and clopidogrel. Gori et al. have reported that dual nonresponsiveness to these drugs increased the risk of DES thrombosis threefold among patients in the RECLOSE trial.

This prospective study included 746 consecutive patients who received sirolimus-eluting or paclitaxel-eluting stents, and who adhered to a 6-month regimen of aspirin (325 mg daily) and clopidogrel (75 mg daily). Assessment of platelet reactivity revealed that 6% of patients were nonresponsive to both aspirin and clopidogrel, and that 11.5% and 6% were nonresponsive to just aspirin and just clopidogrel, respectively. After 6 months of follow-up, DES thrombosis had occurred in significantly more patients with dual nonresponsiveness than in those who were nonresponsive to just aspirin or just clopidogrel, or who responded to both drugs (11.1% versus 2.3%, 2.2% and 2.1%, respectively). The composite outcome of cardiac mortality and DES thrombosis was also significantly more common among individuals with dual nonresponsiveness than other patients. Multivariate analysis revealed that nonresponsiveness to both antiplatelet agents was a significant, independent predictor of DES thrombosis (hazard ratio 3.18, 95% CI 1.14–8.83), and of the composite outcome of cardiac mortality and DES thrombosis (hazard ratio 2.94, 95% CI 1.16–7.41). Although rare, nonresponsiveness to dual antiplatelet therapy could be an important indicator of increased risk of DES thrombosis.