Ten-year HOST-EXAM trial data show clopidogrel reduces major adverse events versus aspirin in chronic PCI maintenanceLong-term clopidogrel may lower risks compared to aspirin after heart stents

This study represents a 10-year extended follow-up of the HOST-EXAM randomized controlled trial, conducted in a setting of chronic maintenance monotherapy following percutaneous coronary intervention (PCI). The population consisted of 5,438 patients who had completed dual antiplatelet therapy without clinical events for 6 to 18 months post-PCI. Participants were randomly assigned to receive either clopidogrel 75 mg once daily or aspirin 100 mg once daily. The median follow-up duration was 10.5 years (interquartile range 9.4 to 11.4 years) after the PCI procedure. The trial was funded by the Ministry of Health & Welfare, South Korea, and is registered with ClinicalTrials.gov.

The primary outcome was defined as 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. Over the follow-up period, the primary composite endpoint occurred in 25.4% of patients in the clopidogrel group versus 28.5% in the aspirin group. The hazard ratio for the primary outcome was 0.86 (95% CI 0.77-0.96; log-rank p=0.0050), indicating a statistically significant lower rate of events with clopidogrel.

Secondary outcomes provided further detail on specific risks. The thrombotic endpoint occurred in 17.3% of the clopidogrel group compared to 20.0% in the aspirin group (log-rank p=0.0024). Similarly, the bleeding endpoint occurred in 9.1% of patients receiving clopidogrel versus 10.8% in the aspirin group (log-rank p=0.020). Regarding all-cause mortality, the results indicated similar rates between the two groups, although specific absolute numbers and p-values for this specific secondary outcome were not reported in the provided data.

Safety and tolerability were assessed through the incidence of Bleeding Academic Research Consortium type ≥3 bleeding. The data demonstrate that clopidogrel was associated with a lower rate of these serious bleeding events compared to aspirin. Specific data regarding discontinuations due to adverse events, other serious adverse events, and general tolerability were not reported in the available evidence. The study design allowed for the observation of long-term safety profiles in a real-world chronic maintenance context.

When compared to prior landmark studies in the therapeutic area of antiplatelet therapy, this extended follow-up reinforces the observation that clopidogrel may offer a favorable risk-benefit profile over aspirin for long-term monotherapy. Previous trials often focused on the acute phase or dual therapy; this study specifically addresses the chronic maintenance phase where patients have already tolerated dual therapy. The results align with the broader understanding that switching to clopidogrel monotherapy after the initial dual therapy period can reduce the risk of major adverse cardiac events without increasing bleeding risk.

Methodological limitations inherent to observational interpretations or specific trial constraints were not explicitly detailed in the provided input, though the distinction between association and causation is preserved in the results description. The study population was restricted to patients who had completed dual antiplatelet therapy without clinical events, which may limit generalizability to patients who experienced events during the dual therapy phase or those who could not tolerate dual therapy. Additionally, the specific funding source and potential conflicts of interest were noted, though no specific conflicts were detailed beyond the funding body.

Clinical implications suggest that clopidogrel can be considered as an alternative to aspirin for long-term antiplatelet monotherapy during the chronic maintenance phase after PCI. This is particularly relevant for patients who have completed the initial dual antiplatelet therapy period and require ongoing protection. However, clinicians must recognize that all-cause mortality was similar between groups, indicating that the benefit of clopidogrel is primarily in reducing the composite of ischemic and bleeding events rather than extending life directly.

Several questions remain unanswered. The long-term impact of these findings on patients with specific comorbidities or those who failed dual antiplatelet therapy is not addressed. Furthermore, the cost-effectiveness of switching to clopidogrel versus continuing aspirin in various healthcare systems requires further evaluation. The study does not provide data on patients who discontinued therapy early or those with specific bleeding diatheses beyond the reported composite bleeding endpoint. Ultimately, while the evidence supports the use of clopidogrel, individual patient factors must guide the final therapeutic decision.