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Impact of Age on Antiplatelet Monotherapy in the Chronic Maintenance Period After Percutaneous Coronary Intervention:
Keehwan Lee1, Jeehoon Kang1, Kyung Woo Park2
1Seoul National University Hospital, Seoul, Korea.
Insights
Clopidogrel monotherapy is beneficial for secondary prevention after percutaneous coronary intervention (PCI), regardless of patient age. Adverse events, including ischemic and bleeding events, increase significantly from age 65.
Area of Science:
- Cardiology
- Interventional Cardiology
- Clinical Trials
Background:
- The HOST-EXAM Extended study demonstrated clopidogrel's superiority over aspirin for secondary prevention post-percutaneous coronary intervention (PCI).
- Age-related impacts on antiplatelet monotherapy efficacy and safety after PCI require specific investigation.
Purpose of the Study:
- To evaluate the influence of age on the effectiveness and safety of antiplatelet monotherapy following PCI.
- To compare clopidogrel monotherapy versus aspirin monotherapy across different age groups.
Main Methods:
- Subgroup analysis of the HOST-EXAM Extended study, including 4717 patients with a median follow-up of 5.8 years.
- Patients were categorized into age groups, with an 'old age' group defined as 65 years or older.
- Primary endpoint: composite of all-cause death, myocardial infarction, stroke, ACS readmission, and BARC bleeding type ≥3. Secondary endpoints: thrombotic events and any bleeding.
Main Results:
- Adverse event risk, particularly ischemic and bleeding events, escalated from age 65.
- Clopidogrel monotherapy reduced the primary endpoint in both older (19.4% vs 23.1%) and younger (7.8% vs 11.7%) patients, with no significant age interaction (P=0.167).
- These benefits were consistent for thrombotic and bleeding endpoints across age groups.
Conclusions:
- Ischemic and bleeding event rates significantly increase in patients aged 65 and older requiring antiplatelet monotherapy post-PCI.
- Clopidogrel monotherapy demonstrates consistent benefits over aspirin monotherapy for secondary prevention after PCI, irrespective of patient age.
Backgrounds:
The HOST-EXAM Extended study reported the benefit of clopidogrel monotherapy over aspirin monotherapy in secondary prevention after percutaneous coronary intervention (PCI). This age-specific subgroup analysis of the study aimed to assess the impact of age on antiplatelet monotherapy after PCI.
Methods:
We analysed data from the per-protocol population (4717 patients) with a median follow-up of 5.8 years. The old age group comprised 2033 patients (43.1%), defined as those 65 years of age or older. The primary end point was the composite of all-cause death, nonfatal myocardial infarction, stroke, readmission due to acute coronary syndrome (ACS), and Bleeding Academic Research Consortium (BARC) bleeding type 3 or greater. The secondary end points were thrombotic composite outcomes and any bleeding.
Results:
Age correlated with an elevated risk of adverse events, particularly from age 65. Clopidogrel monotherapy was associated with a reduction of the primary end point in both the old age group (19.4% vs 23.1%, hazard ratio [HR] 0.802, 95% confidence interval [CI] 0.664-0.968; P = 0.022) and the young age group (7.8% vs 11.7%, HR 0.646, 95% CI 0.506-0.825; P < 0.001), without significant interaction (interaction P = 0.167). These findings were consistent for the secondary composite thrombotic end point and any bleeding events (interaction P value of secondary thrombotic end point: 0.786; interaction P value of any bleeding end point: 0.565). Consistent results were observed in analyses with a 75-year age cutoff and in subgroup analyses by 10-year age intervals.
Conclusions:
In patients requiring antiplatelet monotherapy after PCI, occurrence of both ischemic and bleeding events dramatically increased from age 65. The beneficial impact of clopidogrel over aspirin monotherapy was consistent regardless of age.
Clinical Trial Registration Information:
ClinicalTrials.gov Identifier: NCT02044250.
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