Catheter Ablation and Edoxaban for Secondary Stroke Prevention: Critical Analysis of the STABLED Randomized Trial

Highlights

The Stroke Secondary Prevention With Catheter Ablation and Edoxaban for Patients With Nonvalvular Atrial Fibrillation (STABLED) trial investigated whether catheter ablation combined with oral anticoagulation (OAC) is superior to OAC alone for secondary stroke prevention.

The primary composite end point—including recurrent ischemic stroke, systemic embolism, all-cause mortality, and hospitalization for heart failure—showed no statistically significant difference between the two groups (HR, 1.11; 95% CI, 0.62-2.01).

Catheter ablation demonstrated a high safety profile with only a 1.6% rate of major procedural complications, including cardiac tamponade and periprocedural stroke.

The study was likely underpowered due to a lower-than-anticipated event rate in both cohorts, reflecting the high efficacy of modern direct oral anticoagulants (DOACs) like edoxaban in secondary prevention.

Introduction: The Burden of Recurrent Stroke in Atrial Fibrillation

Atrial fibrillation (AF) remains a leading cause of ischemic stroke globally, significantly increasing the risk of thromboembolic events. For patients who have already survived an initial stroke, the risk of recurrence is particularly high, often leading to cumulative neurological deficit, increased mortality, and a heavy burden on healthcare systems. While oral anticoagulation (OAC) is the cornerstone of secondary prevention, the role of rhythm control—specifically catheter ablation—in reducing long-term thromboembolic risk has been a subject of intense clinical debate.

Catheter ablation is well-established for symptom management and has shown benefits in reducing heart failure hospitalizations and mortality in specific populations, such as those with AF and reduced ejection fraction. However, its efficacy in preventing stroke, particularly as a secondary prevention strategy, has lacked robust randomized evidence. The STABLED trial sought to address this gap by evaluating whether the aggressive rhythm control provided by ablation could offer additive protection over standard edoxaban therapy.

Study Design and Methodology

The STABLED trial was an open-label, parallel-group, randomized clinical trial conducted across 45 specialized centers in Japan. The study enrolled patients between January 2018 and March 2021, with follow-up extending through March 2024. The inclusion criteria targeted a high-risk demographic: patients aged 20 to 85 years with a definitive diagnosis of nonvalvular atrial fibrillation and a recent (within 1 to 6 months) history of ischemic stroke. Participants were required to have a modified Rankin Scale (mRS) score of 3 or less, ensuring they were functional enough to undergo the intervention and follow-up procedures.

Participants were randomized in a 1:1 ratio into two arms:

1. Standard Therapy Group: Patients received edoxaban, a direct factor Xa inhibitor, as the primary pharmacological intervention for stroke prevention.

2. Ablation Group: Patients received standard edoxaban therapy plus catheter ablation. The ablation procedure was scheduled after at least 4 weeks of stable anticoagulation and within 1 to 6 months of the index stroke onset.

The primary end point was a composite of recurrent ischemic stroke, systemic embolism, all-cause death, and hospitalization for heart failure. Secondary end points included the individual components of the primary outcome and safety metrics specifically related to the catheter ablation procedure.

Key Findings: Efficacy and Safety Outcomes

A total of 249 patients (mean age 71.7 years; 75.1% male) were randomized and analyzed. Over a median follow-up period exceeding 3 years, the trial yielded several critical data points:

Primary Composite Outcome

The primary composite end point occurred in 5.6% per person-year in the catheter ablation group compared to 4.9% per person-year in the standard therapy group. The hazard ratio (HR) was calculated at 1.11 (95% CI, 0.62-2.01), which failed to reach statistical significance (p > 0.05). This suggests that the addition of catheter ablation did not provide a superior benefit in preventing the combined risk of stroke, death, or heart failure hospitalization compared to edoxaban alone.

Mortality and Individual Components

When looking at individual components, the mortality rates were 2.8 per 100 person-years in the ablation group and 1.0 per 100 person-years in the standard therapy group. While numerically higher in the ablation group, the small sample size and wide confidence intervals prevent definitive conclusions regarding a mortality signal. Recurrent stroke rates remained relatively low in both groups, highlighting the effectiveness of the baseline edoxaban treatment.

Safety and Procedural Complications

Safety remains a paramount concern in any interventional AF trial involving post-stroke patients. The STABLED trial reported two major ablation-related adverse events (0.8% each for cardiac tamponade and periprocedural stroke), totaling a 1.6% complication rate. This is consistent with or slightly lower than complication rates reported in major AF ablation registries, confirming that the procedure is technically feasible even in a post-stroke population.

Expert Commentary: Interpreting the Neutral Results

The neutral results of the STABLED trial warrant careful interpretation. Several factors may have contributed to the lack of a significant difference between the intervention and control arms. First and foremost is the issue of statistical power. The observed event rate was significantly lower than what the investigators anticipated during the study design phase. This low event rate is likely a testament to the high efficacy of edoxaban in preventing recurrent thromboembolism in the modern era of stroke care.

Furthermore, the trial focused on patients who were already stabilized on OAC. In clinical practice, the primary driver of stroke in AF patients is the failure to maintain adequate anticoagulation or the presence of non-AF related vascular disease (such as carotid stenosis or small vessel disease). Catheter ablation addresses the arrhythmic trigger but does not mitigate these other systemic vascular risks. While ablation is highly effective at reducing the AF burden, it does not necessarily eliminate the need for OAC, especially in patients with a high CHADS2-VASc score who have already experienced a stroke.

Another consideration is the timing of the intervention. Although the trial mandated ablation within 1 to 6 months of the stroke, the biological remodeling of the atria in long-standing AF may not be fully reversed by a single procedure, and the impact on stroke risk may require a much longer observation period or a larger cohort to become evident.

Clinical Implications and Practice Gaps

For clinicians, the STABLED trial reinforces that OAC remains the gold standard for secondary stroke prevention in AF. Catheter ablation should continue to be viewed primarily as a strategy for rhythm control, symptom improvement, and potentially heart failure management, rather than a primary tool for stroke risk reduction in the immediate post-stroke period.

However, the trial does not suggest that ablation is harmful. The low procedural complication rate confirms that if a patient with a recent stroke has symptomatic AF that warrants ablation for quality-of-life reasons, the procedure can be performed safely. The challenge remains identifying the subset of patients where rhythm control might translate into hard clinical outcomes beyond symptom relief.

Conclusion

The STABLED trial provides important evidence that in patients with nonvalvular atrial fibrillation and a recent history of stroke, adding catheter ablation to edoxaban therapy does not significantly reduce the risk of a composite of recurrent stroke, death, and heart failure hospitalization. While the study was likely underpowered to detect small differences, the results underscore the foundational importance of high-quality anticoagulation. Future research should focus on whether specific subgroups, such as those with high AF burden or those intolerant to OAC, might derive greater benefit from early catheter intervention.

Funding and Trial Registration

The STABLED trial was supported by various academic and clinical research grants in Japan. The trial is registered at ClinicalTrials.gov with the identifier NCT03777631.

References

1. Kimura K, Nishiyama Y, Iwasaki YK, et al. Catheter Ablation and Oral Anticoagulation for Secondary Stroke Prevention in Atrial Fibrillation: The STABLED Randomized Clinical Trial. JAMA Neurol. 2026 Mar 2. doi:10.1001/jamaneurol.2026.0155.

2. Marrouche NF, Brachmann J, Andresen D, et al. Catheter Ablation for Atrial Fibrillation with Heart Failure. N Engl J Med. 2018;378(5):417-427.

3. Kirchhof P, Camm AJ, Goette A, et al. Early Rhythm-Control Therapy in Patients with Atrial Fibrillation. N Engl J Med. 2020;383(14):1305-1316.

4. Packer DL, Mark DB, Robb RA, et al. Effect of Catheter Ablation vs Antiarrhythmic Drug Therapy on Mortality, Stroke, Heart Failure, and Hospitalization Among Patients With Atrial Fibrillation: The CABANA Randomized Clinical Trial. JAMA. 2019;321(13):1261-1274.