NEW ORLEANS -- Among patients with atrial fibrillation, radiofrequency ablation appears to reduce the risk of stroke and transient ischemic attacks -- and also shows a trend to a reduction in heart failure events, researchers said here.
A retrospective cohort analysis of 801 matched Afib patient pairs found that the relative risk of stroke events was decreased 40% (P=0.0027) among patients who underwent ablation compared with those treated medically, said Matthew Reynolds, MD, of the Beth Israel Deaconess Medical Center and the VA Boston Healthcare System.
At his poster presentation at the annual meeting of the American College of Cardiology, Reynolds also told MedPage Today that the researchers observed a 37% reduction in heart failure-related events in these Afib patients, but that the reduction did not achieve statistical significance (P=0.0725).
Action Points
- Note that this study was published as an abstract and presented at a conference. These data and conclusions should be considered to be preliminary until published in a peer-reviewed journal.
- This retrospective cohort study showed a reduction in stroke/TIA rates in patients undergoing radiofrequency ablation.
- Further examination of radiofrequency ablation's impact on the risk of stroke/TIA with prospective, randomized trials is warranted.
"We also observed that patients who underwent ablation therapy had a reduction in medication used to control arrhythmias," Reynolds added.
At baseline more than 75% of the patients were being treated with medications to control their Afib. Among patients who underwent ablation, about 40% were still using medication three years later, compared with more than 60% of those who had remained on medical therapy.
For their analysis, Reynolds and colleagues collected information on patients with Afib and their treatments from the Thomson Reuters MarketScan Research Database, which contains individual claims information from employers, health plans, hospitals, Medicare, and Medicaid.
The records included more than 12,000 Afib patients who underwent ablation (either as inpatients or outpatients) and more than 841,000 individuals medically treated between 2005 and 2009.
The analytic start date was a first ablation or a second anti-arrhythmic prescription fill for the medical treatment group.
After eliminating the patients with pacemakers or those who did not receive at least two anti-arrhythmics, the researchers were left with 3,194 ablation patients and 6,028 non-ablation patients.
From this group they were able to gather 801 patient pairs, propensity-matched on the basis of 15 characteristics, including demographics, comorbid conditions, medication usage, and prior stroke or TIA.
About 60% of the matched pairs were men; more than 85% of the cohort was between ages 50 and 80.
While the study results indicated a benefit for ablation in reducing the risk of stroke and TIAs, Matthew stated that randomized trials would provide a more definitive result.
John Vavalle, MD, a fellow in cardiology at Duke University Medical Center, Durham, NC, said the question of whether radiofrequency ablation or medical therapy is better for treating Afib is an important one.
"We have an aging population and atrial fibrillation is increasing common among older people," he told MedPage Today. "Radiofrequency ablation is an expensive procedure that utilizes a lot of medical resources. We need to be certain that the treatment offers advantages to our patients."
"This study is important because it will drive future prospective studies which will give us answers to these questions," he said.
Vavalle indicated that propensity scoring is gaining traction as one method of reducing selection bias in retrospective data.
"The prevalence of atrial fibrillation is 1% but ranges from 0.1% in adults under the age of 55 years to 9% in those who are at least 80 years old," Reynolds said in his presentation.
"The higher prevalence in elderly patients is an important health policy issue because atrial fibrillation significantly increases the incidence of adverse health events including stroke and heart failure," he added.
In addition to finding that ablation reduced stroke and TIA risk, Reynolds' group found that a prior stroke diagnosis increased the risk of subsequent stroke by 4.5-fold (P<0.0001) and the risk of stroke was increased 1.85-fold if individuals with Afib were age 65 or older (P=0.0042).
Disclosures
Reynolds disclosed financial relationships with St. Jude Medical, sanofi-aventis, Biosense-Webster.
Other co-authors are employees or consultants for Biosense-Webster. Vavalle had no disclosures.
Primary Source
American College of Cardiology
Source Reference: Reynolds M, et al "Comparison of long-term stroke or TIA risk between patients with atrial fibrillation who undergo radiofrequency catheter ablation vs. matched patients who have not had an ablation procedure" ACC 2011; Abstract 1056-395.