Aspirin versus clopidogrel for chronic maintenance monotherapy after percutaneous coronary intervention: 10-year follow-up of the HOST-EXAM trial

Clinical Snapshot

Key Findings

• P Value: p=0.0050

• Effect Size: 25.4% vs 28.5% (clopidogrel vs aspirin)

• Primary Outcome: Composite of all-cause death, non-fatal MI, stroke, ACS readmission, and BARC ≥3 bleeding

• Nnt Or Sensitivity: NNT = 32 (based on 3.1% absolute risk reduction over 10 years)

• Confidence Interval: HR 0.86 (95% CI 0.77-0.96)

Clinical Application

Highly feasible - both medications readily available, similar dosing schedules, established monitoring protocols Both aspirin and clopidogrel are PBS-listed for post-PCI patients. Results support RACGP and cardiac society guidelines allowing clopidogrel as alternative to aspirin. TGA-approved indications align with study population. Post-PCI patients who have completed initial DAPT period without events, particularly those at higher bleeding risk or aspirin intolerance

Abstract

BACKGROUND: The long-term clinical outcomes of clopidogrel monotherapy versus aspirin monotherapy after percutaneous coronary intervention (PCI) remain uncertain. We conducted a 10-year follow-up of the HOST-EXAM trial to assess the very long-term effects of clopidogrel versus aspirin monotherapy in this setting. METHODS: In HOST-EXAM, patients who had completed dual antiplatelet therapy without clinical events for 6-18 months after PCI were randomly assigned to receive clopidogrel 75 mg once daily or aspirin 100 mg once daily. This study is an investigator-initiated 10-year extended follow-up of the HOST-EXAM trial. The primary endpoint was a composite of all-cause death, non-fatal myocardial infarction, stroke, readmission due to acute coronary syndrome, and Bleeding Academic Research Consortium type ≥3 bleeding. The primary analysis was done in the intention-to-treat population. The study is registered with ClinicalTrials.gov (NCT02044250) and is complete. FINDINGS: From March 26, 2014, to May 29, 2018, 5530 patients were enrolled and 5438 were randomly assigned to the aspirin group (n=2728) or the clopidogrel group (n=2710). Clinical follow-up status was ascertained on May 1, 2025, resulting in a median follow-up duration of 10·5 years (IQR 9·4-11·4) after PCI and a completion rate of 92·8%. Clopidogrel was associated with a lower rate of the primary composite endpoint than aspirin (Kaplan-Meier estimate 25·4% for the clopidogrel group vs 28·5% for the aspirin group; hazard ratio 0·86 [95% CI 0·77-0·96]; log-rank p=0·0050). Clopidogrel was also associated with a lower rate of the thrombotic endpoint (17·3% vs 20·0%; log-rank p=0·0024) and bleeding endpoint (9·1% vs 10·8%; log-rank p=0·020). All-cause mortality was similar between groups. INTERPRETATION: During 10 years of follow-up, clopidogrel monotherapy, compared with aspirin monotherapy, was associated with lower rates of the primary composite, ischaemic, and bleeding outcomes, but not all-cause mortality after PCI. These findings support consideration of clopidogrel as an alternative to aspirin for long-term antiplatelet monotherapy during the chronic maintenance phase after PCI. FUNDING: Ministry of Health & Welfare, South Korea.