Clopidogrel superior to Aspirin monotherapy after PCI across risk strata: HOST-EXAM analysis

Researchers in their study published in the Journal of the American College of Cardiology revealed a consistent beneficial effect of clopidogrel over aspirin monotherapy irrespective of clinical risk or relative ischemic and bleeding risks compared with aspirin monotherapy.

"Clopidogrel seems superior to aspirin monotherapy over the next 2 years regardless of the patient's baseline clinical risk or relative ischemic and bleeding risks among secondary-prevention patients who are event-free for 6 to 18 months after PCI," the researchers wrote.

"Taken together, favourable clinical outcomes of clopidogrel over aspirin monotherapy can be expected in high ischemic, clinical or bleeding risk patients."

The original study (HOST-EXAM) opened the door to the broader idea of clopidogrel monotherapy use over the usual aspirin for this patient population by showing consistent benefits with the former for bleeding and thrombotic events through 24 months of follow-up. In the analysis, Seokhun Yang, Seoul National University College of Medicine, Seoul, Republic of Korea, and colleagues aimed to evaluate the benefits of clopidogrel across high-risk subgroups.

The researchers randomly assigned patients who were event-free for 6 to 18 months post-PCI on DAPT (dual antiplatelet therapy) to clopidogrel or aspirin monotherapy.

For risk stratification, two clinical risk scores were used: the Thrombolysis In Myocardial Infarction Risk Score for Secondary Prevention (TRS 2°P) (the sum of age ≥75 years, hypertension, diabetes, peripheral artery disease, current smoking, stroke, heart failure, coronary artery bypass grafting, and renal dysfunction).

The primary composite endpoint of the study was determined as a composite of nonfatal myocardial infarction, all-cause death, readmission because of acute coronary syndrome, stroke, and major bleeding (Bleeding Academic Research Consortium type ≥3) at 2 years after randomization.

The analysis led to the following findings:

• Among 5,403 patients, clopidogrel monotherapy showed a lower rate of the primary composite endpoint than aspirin monotherapy (HR: 0.73; 95% CI: 0.59-0.90).
• The benefit of clopidogrel over aspirin was consistent regardless of TRS 2°P (high TRS 2°P [≥3] group: HR: 0.65; and low TRS 2°P [<3] group: HR: 0.77) and regardless of DAPT score (high DAPT score [≥2] group: HR: 0.68; and low DAPT score [<2] group: HR: 0.75). The association was similar for the individual outcomes.

The findings suggest that clopidogrel monotherapy can be a preferred option over aspirin monotherapy for secondary prevention after PCI, regardless of the patient's risk profile.

“Clinicians might consider these results when making therapeutic decisions for the choice of antiplatelet agents following DAPT, especially for high-risk patients," the investigators concluded.

Reference:

Yang S, Kang J, Park KW, et al. Comparison of antiplatelet monotherapies after percutaneous coronary intervention according to clinical, ischemic, and bleeding risks. J Am Coll Cardiol. 2023;82:1565-1578.