Streamlined Procedure Maintains Benefits of Cryoablation Over Drugs for Paroxysmal A-fib
The AVATAR-AF trial will hopefully restart the debate about the best way to deliver catheter ablation for A-fib, the researcher says.
LISBON, Portugal—Ablation of paroxysmal A-fib using a cryoballoon cuts down on the need for patients to receive hospital-based care compared with antiarrhythmic drug therapy even if the procedure is performed without pulmonary vein (PV) mapping catheters, a finding that could have substantial cost implications, the AVATAR-AF trial shows.
In the first year of follow-up, 76% of patients treated with drug therapy alone received hospital care for atrial arrhythmias, which is significantly higher than the rate in the patients who underwent the streamlined ablation procedure (21%; P < 0.0001), Prapa Kanagaratnam, MB BChir (Imperial College Healthcare NHS Trust, London, England), reported at the European Heart Rhythm Association Congress 2019 here.
Cryoablation with PV mapping, however, was not superior to ablation without mapping (18%; P = 0.6061), counter to what was expected going into the trial, Kanagaratnam told TCTMD.
That’s a “slightly more controversial part of the trial,” he admitted. But, it “really calls into question a lot of these assumptions we’ve made about what is an essential part of the procedure.” Now that ablation has been shown to effectively relieve the burden of A-fib, Kanagaratnam said it’s time to go further, noting, “We need to figure out how we actually deliver the therapy in the best form.”
The approach used in AVATAR-AF, he said, should be associated with major cost savings across different healthcare models because an expensive part of the procedure is being removed. In the United Kingdom, for instance, the stripped-down procedure should be about 30% cheaper, which means that for the same budget, about 30% more patients could be treated, he said. Savings should also be seen in private healthcare models.
That is a key advantage to using an approach to cryoablation like that used in AVATAR-AF, agreed Oussama Wazni, MD (Cleveland Clinic, OH), who was not involved in the study. “Now, in an era where costs are rising but we’re getting paid less, I think that’s an important consideration,” he commented to TCTMD, adding, too, that “the less time you have to spend in the left atrium, the better.”
Wazni said he was encouraged by the findings because when he performs cryoablation (most of his procedures are with radiofrequency energy), he does it without PV mapping. “That validates my practice, that this is reasonable to do,” he commented.
Focusing on the Patient and Simplifying
Part of the philosophical background of AVATAR-AF, Kanagaratnam explained, was a desire to change the way physicians think about the success of A-fib ablation, shifting from trying to eliminate short bouts of A-fib on monitoring—which itself has financial costs and requires patients to visit the doctor’s office, even if they’re feeling fine—to focusing on outcomes more tangible for patients. That’s why the primary outcome of the trial was all hospital episodes related to treatment of atrial arrhythmias, which was driven by patients seeking care when they had symptoms and not by continuous monitoring.
The researchers then thought about ways that they could simplify the ablation procedure to reduce cost, with an eye toward meeting the anticipated growth in demand for catheter ablation as A-fib becomes more common in the coming decades. They identified PV mapping as something that has become standard practice but might not be necessary.
In AVATAR-AF, they tested this stripped down cryoablation procedure against antiarrhythmic drug therapy and additionally including a third arm for standard cryoablation to head off anticipated criticisms about whether efficacy would be sacrificed with the streamlined approach. Ablations were performed as same-day procedures to further reduce cost.
The trial included 321 patients with documented paroxysmal A-fib, most of whom (about 60%) were not taking any class I or III antiarrhythmic agents for symptom control at baseline; the rest were taking one. Over the 12-week treatment period, the proportion of patients taking an antiarrhythmic dropped to 12.7% in the streamlined ablation group and 16.7% in the conventional ablation group; it increased to 75.7% in the drug arm as physicians sought to optimize symptom control.
The results at 1 year show both that cryoablation can be performed effectively without PV mapping and that ablation overall reduces the need for patients to seek care for atrial arrhythmias at the hospital.
“So we believe that it is possible to simplify AF ablation procedures without compromising outcomes,” Kanagaratnam said during his presentation. “And our data supports the use of AF ablation in patients naïve to class I and class III antiarrhythmic agents.”
He pointed out that a recent international consensus statement gave use of catheter ablation in patients with symptomatic A-fib who had not yet tried an antiarrhythmic agent a class IIa recommendation (“is reasonable”) and told TCTMD that AVATAR-AF supports strengthening that advice.
Wait for STOP AF First
Wazni said it was too soon for changes to the guidelines to advocate for greater use of ablation over antiarrhythmic drugs, pointing out that more information will be coming from the ongoing STOP AF First trial (for which he is one of the principal investigators). In that trial, all patients have new, symptomatic, paroxysmal A-fib; are drug-naive; and are being randomized to either cryoablation or drug therapy. “The thought process is that the sooner you intervene on those patients in the long run, the better the outcome,” Wazni said.
For now, the main impact of AVATAR-AF will be in showing that the cryoablation procedure can be streamlined, he said, “and people will be more confident not mapping after doing a cryoablation, at least the first one.” If an additional ablation is needed, he said, mapping and a point-by-point catheter using radiofrequency energy should be used to “touch up” any missed spots.
Speaking to the ablation in general, Wazni said, “I think this is exciting. Everything is going in the right direction, meaning ablation works. It does reduce the burden of atrial fibrillation. It’s not going to eliminate it, I don’t think, but it does decrease the burden of A-fib, and I think our patients will be better off for it.” Even CABANA, which showed that A-fib ablation failed to improve clinical outcomes, demonstrated that ablation reduced A-fib recurrence and improved symptoms, he pointed out.
An important take-home message from AVATAR-AF for Kanagaratnam was that “we need to put the patient at the center of our thinking for the pathway, as opposed to what we do at the moment, which is we put the electrophysiologist at the center. . . . If I can achieve that change in thinking, then I think we’ve done a lot.”
Photo Credit: Medtronic
Kanagaratnam P. AVATAR-AF: ablation versus antiarrhythmic therapy for reducing all hospital episodes from recurrent atrial fibrillation. Presented at: EHRA 2019. March 17, 2019. Lisbon, Portugal.
- AVATAR-AF received funding from Medtronic and the British Heart Foundation.
- Kanagaratnam reports consulting for and receiving research contracts from Medtronic; consulting for Abbott; and consulting for and receiving royalties from Biosense Webster.
- Wazni reports consulting for Boston Scientific, Medtronic, and Biosense Webster.