The adverse event rate in the ablation arm was “surprisingly” low, said Dr. Packer, with a 3.9% rate of complications from catheter insertion (more than half were hematomas), a 3.4% rate of complications from catheter manipulation within the heart (2.2% involved pericardial effusions that required no intervention), and a 1.8% rate of ablation-related events, most commonly severe pericardial chest pain. “The risks of ablation seem to be lower than we thought,” he said, but quickly added the caveat that all ablation operators in CABANA had to have performed at least 100 ablation cases prior to the trial. The observed safety applies to operators “who know what they’re doing,” he said. Adverse events in the medically treated patients were typical for patients treated with amiodarone, Dr. Packer said, with the most common events hyper- or hypothyroidism, in 1.6%, and an allergic reaction, in 0.6%. In the intention-to-treat analysis the incidence of recurrent AF following a 90-day blanking period after ablation was 47% lower in the ablated patients relative to the drug-treated patients (P less than .0001).
Dr. Packer also presented an intriguing subgroup analysis for the primary endpoint that showed ablation had the best performance relative to medical management in patients younger than 65 years, patients with a history of heart failure, minority patients, and those who entered the trial in NYHA functional class II or III. The subgroup analysis showed a signal for worse performance from ablation in patients who were at least 75 years old. “I’m concerned about these older patients; we need to look into this,” Dr. Packer said. He also expressed optimism that the good performance of ablation in heart failure patients, while an exploratory finding, suggested confirmation of the results reported recently from the CASTLE-AF trial, which also showed good outcomes from catheter ablation for treating patients with heart failure and AF (N Engl J Med. 2018 Feb 1;378[5]:417-27).
The main qualification Dr. Packer voiced about the CABANA results is that not every AF patient should get ablation. “All treatments are not right for all patients. Not everyone with AF needs ablation. You need to talk with patients about it.” But despite this caution, he declared that the results had already changed his practice.
“I much less often now say to patients ‘let’s go with a drug and see what happens.’ I’d still do that if I wasn’t sure that a patient’s symptoms were caused by their AF” as opposed to their underlying heart disease, but if I’m pretty certain that their symptoms are caused by their AF over the past few months, I’ve become more likely to say that front-line ablation is reasonable,” Dr. Packer said.