Platelet function is evaluated using a validated method: the VerifyNow System (Accumetrics Inc., San Diego, CA), which is a point-of-care turbidimetry-based optical detection system that measures platelet-induced aggregation. These value are measured Platelet function, measured with the VerifyNow P2Y12. All patients on chronic dual antiplatelet therapy (>1 month) quit smoking for a 2 weeks period. Therefore PRU values are obtained at baseline (at the enrollment time) and after 2 weeks after smoking cessation. Platelet reactivity are expressed in P2Y12 reaction units (PRU). PRU values >240 are suggestive of high platelet reactivity.