Ablation Associated with Lower Long-Term Risk of Stroke Compared to Cardioversion in Patients with Atrial Fibrillation

An analysis of more than 20,000 records indicates that patients who choose catheter ablation rather than cardioversion for atrial fibrillation (AF) face an elevated stroke risk immediately after the procedure but a lower stroke risk thereafter.

Mayo Clinic researchers pulled records for 12,122 people who underwent catheter ablations for AF from a national administrative claims database. They then looked at another 12,122 people — matched to those in the first group age, sex, year-of-treatment, CHA2DS2-Vasc score, and Charlson index— who had undergone cardioversion instead.

Claims records for the 30-day period after each procedure showed that 0.5% of the catheter ablation group but just 0.3% of the cardioversion group suffered ischemic stroke, hemorrhagic stroke, or transient ischemic attack (relative risk [RR], 1.53; p=0.05).

After 30 days, however, the relative frequency of claims was reversed. Ablation patients, in the long-term, were significantly less prone to strokes and transient ischemic attacks than cardioversion patients (RR 0.78; p=0.03).

Previous research had demonstrated that catheter ablation can significantly reduce the disease burden associated with AF. Several studies, moreover, had tallied short-term adverse events in ablation patients.

But the authors of the new analysis, which appears in Heart Rhythm, believe that theirs is the first to compare the long-term incidence of strokes and transient ischemic attacks in ablation patients and similar patients who chose another treatment option.

The authors conclude that catheter ablation is clearly associated with a relatively low risk of strokes, particularly for patients who get past the 30-day window unscathed, but the risks for ablation patients today may actually be somewhat lower than the study indicates.

Patients included in the new analysis all underwent their procedures between 2005 and 2012, but research published since 2012 has found several potential ways to reduce the risk of strokes and other adverse events during and immediately after ablations.

For example, a randomized trial that was written up last year in Circulation compared the incidence of thromboembolic and hemorrhagic events in 790 patients who discontinued warfarin before ablation and 794 who kept using it normally.

Patients in the first group suffered 39 adverse events (including 29 strokes) in the 48 hours after surgery. Patients in the second group suffered 2 strokes and no transient ischemic attacks (P=<0.001). Multi-variable analysis, not surprisingly, found the common practice of discontinuing warfarin before ablation to be associated with a massive increase in the risk of thromboembolic and hemorrhagic events (odds ratio [OR], 13; 95% confidence interval [CI], 3.1 to 55.6; p<0.001).

Another factor that might reduce the risk of post-ablation stroke is the steady advance in the technologies and techniques used in ablations.

For example, a study of ablations performed between 2010 and 2012 and published in the Journal of Cardiovascular Electrophysiology found that the use of novel contact force sensing (CFS) technology increased the effectiveness of ablations on patients with paroxysmal AF.

The use of a CFS catheter more than doubled the chances that ablation would keep hearts beating properly throughout the follow-up period that averaged about a year (hazard ratio [HR], 2.24; 95% CI, 1.29—3.90; p = 0.004).