"Catheter ablation was superior to medical therapy for rhythm control of AF in all age groups including the elderly in this study," Dr. Tristam Bahnson of Duke Center for Atrial Fibrillation in Durham. "The trend towards decreasing benefits...with advancing age for the mortality-inclusive endpoints over the long term should be interpreted with caution, due to a variety of factors including the limited number of patients in the oldest age category."
"Both catheter ablation and medical therapy remain reasonable strategies to treat AF in elderly patients, and catheter ablation remains the preferred option when/if medical therapy fails," he said.
"The analysis of mortality-inclusive outcomes...demonstrates a relationship between patient age and outcome whereby the youngest patients derive the most benefit of catheter ablation," he continued. "This observation is relevant to physicians and patients who must weigh the relative merits of catheter ablation versus medical therapy when choosing treatment plans for AF, and support the notion that younger patients with AF may benefit most from choosing catheter ablation as a preferred strategy early in their treatment."
"Independent of age, patients who cannot undergo full-dose anticoagulation, who are critically ill or unstable prohibiting safe conduct of an interventional procedure, or who have very recently undergone cardiac or thoracic surgery are typically not candidates for AF ablation," he added.
As reported in Circulation, among 2,204 AF patients randomized to catheter ablation or drug therapy in CABANA, 766 (34.8%) were <65; 1,130 (51.3%) were 65-74; and 308 (14%) were 75 or older.
The primary outcome was a composite of death, disabling stroke, serious bleeding, or cardiac arrest. Secondary outcomes included all-cause mortality, the composite of mortality or cardiovascular hospitalization, and AF recurrence.
Catheter ablation was associated with a 43% reduction in the primary outcome for those under age 65 (adjusted hazard ratio, 0.57); a 21% reduction for ages 65-74 (aHR 0.79); and an indeterminate effect for ages 75 and older (aHR 1.39).
Four-year event rates for ablation versus drug therapy across age groups were 3.2% versus 7.8% in patients under age 65; 7.8% versus 9.6% in those 65-74; and 14.8% versus 9% for those 75 and older.
For every 10-year increase in age, the primary outcome aHR increased (i.e., less favorable to ablation) an average of 27%. A similar pattern was seen with all-cause mortality - i.e., for every 10-year increase in age, the aHR increased an average of 46%.
AF recurrence rates were lower with ablation compared to drug therapy across age groups (aHR 0.47, 0.58, and 0.49, respectively), whereas treatment-related complications were infrequent in both arms (<3%), regardless of age.
Dr. Pedram Kazemian, Program Director - Clinical Cardiac Electrophysiology Fellowship at Deborah Heart and Lung Center in Brown Mills, New Jersey, commented on the study in an email to Reuters Health. "Since the main goal of AF ablation is maintenance of sinus rhythm, older patients who have larger number of comorbidities, hence lower chance of successful ablation, are more likely to be deemed unsuitable for this procedure."
"But this is a function of their overall health, rather than just age," he said. "Perhaps a better method for deciding on suitability of ablation would be a composite score that incorporates age with other risk factors."
"However," he noted, "the findings are difficult to explain, as the authors also mention, in the sense that the older patients in this particular study had roughly the same success rate in terms of maintaining sinus rhythm and were not 'sicker' than the younger cohorts (with some minor exceptions that the study corrected for), but ended up with poorer outcome after ablation."
The authors did not provide any satisfactory explanation for these findings, Dr. Kazemian said, and acknowledge that bias may possibly played a role - i.e., "cutting the trial cohort into subgroups even when analysis is done by intention to treat creates the possibility for complex, difficult to detect biases to influence observed results."
The study was funded in part by Biosense Webster, Medtronic, and Boston Scientific. Dr. Bahnson and four coauthors have received funds from one or more of the companies.
SOURCE: https://bit.ly/3zwyf8t Circulation, online December 22, 2021.
By Marilynn Larkin
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