First-line Ablation With Cryoballoon Gains Support From STOP AF First

Patients with symptomatic paroxysmal A-fib stand a better chance of being in sinus rhythm at 1 year if they undergo first-line catheter ablation with a cryoballoon rather than start antiarrhythmic drug therapy, the STOP AF First trial shows.

The rate of treatment success—which included freedom from documented atrial arrhythmias—was 75% in patients initially treated with ablation and 45% in those initially treated with antiarrhythmic drugs (P < 0.0001), Oussama Wazni, MD (Cleveland Clinic, OH), reported during the virtual European Society of Cardiology (ESC) Congress 2020.

First-line ablation appeared to be safe, with only two serious adverse events observed—a significant pericardial effusion in the first 30 days and an MI in the first 7 days.

Wazni pointed out that another trial presented at ESC 2020, EAST-AFNET 4, showed that early initiation of rhythm-control therapy in patients recently diagnosed with A-fib—mostly with antiarrhythmic drugs, but with some ablation—reduced the risk of CV events compared with usual care.

“If you take the findings of our study together with the EAST-AFNET 4 study, which showed that if you can control the rhythm you will have less [adverse] cardiovascular outcomes later, then it makes sense that if you’re going to intervene early for rhythm control then ablation is the way to go, and not antiarrhythmic drugs,” Wazni told TCTMD.

Mounting Evidence

In his presentation, Wazni pointed out that sinus rhythm is more difficult to restore as A-fib progresses and that progression of the arrhythmia has been associated with increased risks of heart failure hospitalization and mortality, as well as impaired quality of life.

Three earlier trials—RAAFT-1, RAAFT-2, and MANTRA-PAF—have shown that first-line catheter ablation modestly improves freedom from A-fib recurrence compared to antiarrhythmic drug therapy, supporting a class IIa recommendation for the approach in international guidelines. In all of those trials, ablation was performed with radiofrequency energy.

It makes sense that if you’re going to intervene early for rhythm control, then ablation is the way to go, and not antiarrhythmic drugs. Oussama Wazni

The STOP AF First trial adds to that evidence base in that ablation was performed using the Arctic Front Advance cryoballoon (Medtronic). The US Food and Drug Administration-regulated trial, conducted at 24 sites, included 203 patients with symptomatic paroxysmal A-fib who had been free from antiarrhythmic drug therapy for at least 7 days prior to enrollment. They were randomized to pulmonary vein isolation with the cryoballoon or class I or III antiarrhythmic medications.

The patients were relatively healthy, with few comorbidities, Wazni said. Their men age was about 61, and roughly 60% were men.

The primary efficacy outcome was freedom from treatment failure, which was a composite of acute procedural failure; any subsequent A-fib surgery or ablation in the left atrium; documented A-fib, atrial tachycardia, or atrial flutter; cardioversion; or use of class I or III antiarrhythmic drugs after the 90-day blanking period. Patients who underwent ablation fared better on this endpoint through 1 year. The most common reason for treatment failure in both groups was a documented atrial arrhythmia (21 in the ablation arm and 35 in the drug-therapy arm).

The primary safety outcome was a composite of procedure- and system-related serious adverse events, including TIA, stroke, major bleeding, MI, or vascular complication in the first 7 days; significant pericardial effusion within 30 days; and symptomatic pulmonary vein stenosis, atrial-esophageal fistula, or unresolved phrenic nerve injury within 1 year. The observed rate was 1.9% with ablation, coming in well below the performance goal of 12% (P < 0.0001).

‘Think About Ablation a Little Bit Earlier’

These results are more confirmatory of the prior trials using radiofrequency energy for ablation than they are novel, Luigi Di Biase, MD, PhD (Montefiore Medical Center, Bronx, NY), who was not involved in the study, commented to TCTMD. He noted also that the FIRE AND ICE trial showed that cryoablation was comparable to radiofrequency ablation for patients with paroxysmal A-fib.

“I feel that the results of [STOP AF First] are confirming that even if you use a different energy source, the results of first-line therapy do not change,” said Di Biase, a member of the electrophysiology section of the American College of Cardiology.

Like Wazni, Di Biase said these results fit together with those from EAST-AFNET 4. “If you put all this information together, I think that the general cardiologist should think about ablation a little bit earlier than what we used to do in the past.”

Quality of life is what we want for our patients and what I want for my patients. Luigi Di Biase

There is a reluctance on the part of referring physicians to suggest ablation as a first-line option, both because it has been thought of as an invasive procedure that comes with complications and because administering antiarrhythmic medications is more accessible as an initial treatment strategy. Also, guidelines used to recommend against ablation unless a patient had failed antiarrhythmic drug therapy.

Alone, STOP AF First, which is limited by relatively small patient numbers, is not enough to change guidelines, but the totality of the evidence now available does support strengthening the recommendation for first-line ablation, Di Biase said.

“I think we’re building up a lot of evidence that staying in sinus rhythm is better than controlling the rate or than other treatments,” he said. “And this trial also confirms first-line [ablation] is better than antiarrhythmic medication. So why do you want to do something with medication when you know that the best way to try to maintain sinus rhythm is the ablation, as long as you now know that the complication rate of ablation is not that high, it’s actually reasonable?” A low complication rate was seen in CABANA, as well, he added.

Wazni also indicated that a guideline change might be warranted: “Taken all together, I think there’s a good argument for first-line ablation to become a class I indication with very good level of evidence.”

Physicians should not forget about quality of life either, Di Biase stressed. “Quality of life is what we want for our patients and what I want for my patients. . . .  Patients who are symptomatic with atrial fibrillation need to be offered the best treatment possible today to be given a chance to have a better quality of life, irrespective of anything else. And I think that ablation provides that.”