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News & Articles > HOST-EXAM: Aspirin versus clopidogrel for chronic maintenance monotherapy after PCI

Debra L. Beck and Eugene Braunwald, MD 

After percutaneous coronary intervention (PCI), guidelines recommend indefinite maintenance therapy with a single antiplatelet agent after the initial 6- to 12-months of dual antiplatelet therapy (DAPT). Aspirin is the most widely used standard antiplatelet agent, with clopidogrel recommended as an alternative strategy. The HOST-EXAM trial was an investigator-initiated, prospective, randomized, open-label, multicenter trial comparing the efficacy and safety of aspirin and clopidogrel monotherapy in patients after PCI.  

Participants included 5,436 patients (mean age, 63 years; 75% men) who had undergone drug-eluting coronary stenting and completed 6 to 18 months of DAPT without experiencing a clinical event. Patients were randomly assigned to aspirin 100 mg once daily or clopidogrel 75 mg once daily for 24 months.  

Clopidogrel was superior to aspirin for the primary composite endpoint of all-cause death, non-fatal myocardial infarction (MI, stroke, readmission due to acute coronary syndrome, and major bleeding (5.7% vs. 7.7%; hazard ratio [HR], 0.73; p=0.0035).  

Secondary outcomes also favored treatment with clopidogrel over aspirin, including a thrombotic composite outcome of cardiac death, non-fatal MI, ischemic stroke, readmission for ACS, and definite or probable stent thrombosis; HR, 0.68; p=0.002).  


“In patients who were event-free under DAPT for 6 to 18 months after PCI with drug-eluting stenting, clopidogrel monotherapy, compared with aspirin monotherapy significantly reduced the risk of the composite of all-cause death, non-fatal myocardial infarction, stroke, readmission due to acute coronary syndrome, and BARC bleeding type 3 or greater,” reported Dr. H-S Kim. “The beneficial effect of clopidogrel was observed in thrombotic composite endpoints as well as any bleeding endpoint.” Follow-up is continuing in this cohort.  


ACC 2021 Late-Breaking Clinical Trial: Aspirin vs. clopidogrel during chronic maintenance monotherapy after percutaneous coronary intervention: The HOST-EXAM randomized controlled trial. Presented on May 16 by H-S Kim.  

Koo B-K, Kang J, Park KW, et al. Aspirin versus clopidogrel for chronic maintenance monotherapy after percutaneous coronary intervention (HOST-EXAM): an investigator-initiated, prospective, randomised, open-label, multicentre trial. Lancet 2021; published online May 16. 

Braunwald’s Heart Disease: A Textbook of Cardiovascular Medicine features a unique update program by Dr. Braunwald, creating a “living textbook” by featuring twice monthly updates including “Hot off the Press” and Late-Breaking Clinical Trials (links to authors’ presentation slides are also included).

Learn more about Braunwald’s Heart Disease: A Textbook of Cardiovascular Medicine, 11th Edition. Download a free chapter here.

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