Efficacy and safety of clopidogrel after PCI with stenting in patients on oral anticoagulants with acute coronary syndrome

Aims: To evaluate crude cardiovascular risk in patients with acute coronary syndrome (ACS) who are on oral anticoagulants (OAC) after percutaneous coronary intervention with stents (PCI-S) and also to evaluate if the patients on OAC after PCI-S benefit from clopidogrel. Methods and results: Data from RIKS-HIA and SCAAR on patients admitted to coronary care units 1997 to 2005, undergoing PCI-S (n=27,972), were evaluated. OAC were prescribed to 4.2% (n=1,183) of the patients and they had higher crude 1-year mortality than the non-OAC group, (3.6% [n=421 vs. 1.5% [n= 413], p=0.008), but after adjusting for pre-treatment patient characteristics there were no significant difference in 1-year mortality (adjusted risk ratio [adj. RR] 0.82 [95% CI 0.58-1.16]). Of patients on OAC, 56% (n=659) were also on clopidogrel at discharge. Incidence of death or myocardial infarction (MI) within one year did not differ between the clopidogrel and non-clopidogrel group, adj. RR 0.93 (95% Cl 0.65-1.34). Triple therapy (OAC, clopidogrel plus aspirin) was associated with four times higher risk of any bleeding than OAC plus aspirin, adj. RR 4.27 (95% Cl 1.2-15.1) but a lower incidence of death or MI than OAC plus clopidogrel adj. RR 0.63 (95% Cl 0.40-0.99) Conclusions: Patients discharged on OAC after PCI-S in ACS have higher crude 1-year mortality than patients not on OAC, largely explained by age and comorbidities. Adding clopidogrel is not associated with lower incidence of death or MI at one year. Triple therapy is associated with higher risk of any bleeding than OAC plus aspirin but lower risk of death or MI than OAC plus clopidogrel.