CYP2C19 and coronary artery disorder: However, smoking as an independent risk factor for CAD, could enhance the drug responsiveness of clopidogrel in patients with acute coronary syndrome (ACS) (8, 9), which indicated that smokers could get greater clinical benefit compared with non-smokers, further indicating a correlation between smoking and CYP2C19 gene polymorphisms and the efficacy of clopidogrel treatment.