Two-Thirds of Patients Free From AF Without Drugs 5 Years After Surgical Ablation

August 19, 2015

UPDATED August 21, 2015 // ST LOUIS, MO — For patients with atrial fibrillation (AF) treated with surgical ablation, nearly 80% were free from the arrhythmia and two out of every three were free from AF without the use of antiarrhythmic medications at 5 years, according to the results of a new analysis[1].

The late outcomes, reported by Dr Matthew Henn (Washington University School of Medicine, St Louis, MO) and colleagues, are retrospective and based on procedures performed at a single center but are consistent with the "good early and midterm results" of patients undergoing surgical ablation with the Cox-Maze IV procedure.

In the study, published online August 8, 2015 in the Journal of Thoracic and Cardiovascular Surgery, the researchers also found that the duration of preoperative AF and length of hospital stay were independent predictors of ablation failure at 5 years.

"The Cox-Maze IV [procedure] remains the most successful surgical treatment for AF, even in patients with nonparoxysmal AF and regardless of the complexity of the concomitant procedures," write Henn and colleagues. "The duration of preoperative AF predicted failure at 5 years and suggests the need for earlier intervention."

To heartwire from Medscape, senior investigator Dr Ralph Damiano (Washington University School of Medicine) said candidates for surgical ablation of AF are typically patients who have failed one or more catheter ablations or are poor candidates for catheter ablation.

"Patients who tend to be referred for surgery are those with left atrial appendage thrombus, long durations of AF, a large atrium, and patients who have concomitant cardiac disease, most commonly valve pathology," said Damiano. "The Cox-Maze procedure has the highest success rate of any single procedure, but is clearly more invasive than catheter ablation. It can be done with a minimally invasive approach, however, and this has further limited morbidity."

The Cox-Maze procedure has been modified over the years such that a combination of radiofrequency and cryothermal ablation lines have replaced the surgical incisions in the original "cut-and-sew" technique, explain the researchers. Although the procedure is the gold standard for surgical AF ablation, data on the long-term freedom from AF are somewhat lacking.

At their institution, Barnes Jewish Hospital, where the Cox-Maze procedure was developed and first performed in 1987, the researchers prospectively collected data on 532 consecutive patients with AF undergoing the Cox-Maze IV procedure and 44 patients undergoing a left-sided Cox-Maze procedure with or without a concomitant procedure. Most of the patients, including 77% of the paroxysmal and 81% of the nonparoxysmal AF patients, underwent a sternotomy, while the rest were treated with a right-sided minithoracotomy.

In the overall cohort, freedom from atrial tachyarrhythmia at 1, 2, 3, 4, and 5 years was 92%, 88%, 87%, 81%, and 73%, respectively. Similarly, freedom from atrial tachyarrhythmias without the use of antiarrhythmic medication was 81%, 78%, 77%, 69%, and 61%, respectively. Freedom from atrial tachyarrhythmias was even higher, with and without the use of medication, among individuals who underwent a "boxed lesion set," a modification to the procedure that involves completely isolating the entire posterior left atrium.

"The major advantage of a Cox-Maze procedure is that it has a higher single-procedure success rate than catheter ablation and is quite durable," said Damiano. "Five-year freedom from AF with our most recent version of the Cox-Maze IV was 78%. This was the same regardless of the type of AF. The 5-year freedom from AF after a single catheter ablation has been less than 30% in reported series."

Another advantage of the surgical Cox-Maze IV procedure, noted Damiano, is the removal of the left atrial appendage, and this reduces the future risk of stroke.

Overall, the researchers observed no difference in clinical outcomes among patients with paroxysmal and nonparoxysmal AF, nor were there any differences in long-term freedom from AF among patients undergoing ablation alone or with a concomitant surgical procedure.

In an editorial[2], Dr Robert Hawkins and Gorav Ailawadi (University of Virginia, Charlottesville) point out that majority of studies in the AF literature are retrospective analyses. One trial, the Atrial Fibrillation Catheter Ablation Versus Surgical Ablation Treatment (FAST) trial, did show more patients were free from atrial tachyarrhythmias without antiarrhythmic medications with surgery, but the incidence of adverse events was more than double the rate observed among patients treated with catheter ablation.

Most important, Hawkins and Ailawadi say the latest report by Henn and colleagues is fraught with inconsistencies, which make the data difficult to interpret. "This includes differing types of AF, heterogeneous concomitant operations, multiple lesion sets and energy sources, and inconsistent postablation monitoring," write the editorialists. "As such, direct comparisons of surgical ablation strategies or even against catheter ablation are not appropriate. Moreover, without controls or selection criteria, it is difficult to account for the selection bias."

They suggest that more study is needed, especially in more homogenous patient populations and with more rigorous monitoring to make stronger conclusions. "Nevertheless, this report provides strong evidence that surgical AF ablation should be considered, especially when the preoperative duration is shorter (less than 5 to 10 years) and left atrial size is not prohibitive," they write.

The study supported by grants from the National Institutes of Health. Henn has no relevant financial relationships. Disclosures for the coauthors are listed in the article. Ailiwadi reports consulting fees from Abbott Vascular, Mitralign, and Edwards and speaking fees from St Jude Medical. Hawkins reports no relevant financial relationships.

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