Ablation lowers stroke rate across all risk profiles

Patients with atrial fibrillation treated with ablation had a lower risk of stroke than those left untreated across all age and risk profiles in a study published in the September issue of Heart Rhythm.

T. Jared Bunch, MD, of the Intermountain Heart Institute in Salt Lake City, and colleagues used the Intermountain Atrial Fibrillation Study Registry to look at long-term risk of stroke in atrial fibrillation patients who underwent catheter ablation. They stratified patients into one of three groups enrolled in differing periods between 1984 and 2009: atrial fibrillation patients who received ablation therapy; patients with a history of atrial fibrillation who did not undergo ablation; and patients with no history of atrial fibrillation.

The 4,212 atrial fibrillation patients who underwent ablation were matched 1:4 by age and sex to the other two patient groups for a mean follow-up of 2.9 years. The primary outcome was stroke based on diagnosis codes.

Baseline demographics in the three groups varied slightly. The group with no history of atrial fibrillation was younger with lower rates of hypertension, heart failure and valve disease. The atrial fibrillation group that did not undergo ablation had higher rates of diabetes and prior stroke, and the group that received ablation had higher rates of hypertension, transient ischemic attack and valvular heart disease.

At one year, 2.4 percent of the patients had a stroke. The rate for atrial fibrillation patients who did not undergo ablation was 3.5 percent vs. 1.4 percent for ablation patients and 1.4 percent for patients with no history of atrial fibrillation. The benefit of ablation compared with no ablation was seen in all age groups and across CHADS2 risk profiles.

They suggested several reasons for the findings. Ablation may arrest the progression of changes in the atrium. Alternatively, patients who undergo ablation may be more aggressive about seeking treatment for other stroke risk factors, or they may be healthier.

The authors emphasized that the data do not include long-term success rates and they recommended physicians follow long-term stroke prevention strategies based on CHADS2 scores. They acknowledged that catheter ablation carries some risk but compared with long-term use of antiarrhythmic medications “these risks typically are realized upfront with the procedure whereas those with medications are observed continually over time.”

Yasuo Okumura, MD, PhD, of Nihon University School of Medicine in Tokyo, wrote in an accompanying editorial that the study population may better reflect a real-world cohort than seen in clinical trials. Okumura cautioned that the analysis did not include data on anticoagulation therapy medication and proposed that clinical follow-up in the ablation group might explain the lower stroke rate.