Medtronic has announced the presentation of results of three studies which it says demonstrate that cryoablation is superior to drug therapy for first-line treatment for the prevention of paroxysmal atrial fibrillation (PAF). Two studies—Cryo-FIRST trial and the investigator-initiated EARLY AF— were presented at the American Heart Association Scientific Sessions (AHA 2020, 13–17 November, virtual). These come alongside the publication of the results of the STOP AF clinical trial in the New England Journal of Medicine (NEJM) this week.
Results from the STOP AF trial reveal that cryoablation with the Arctic Front Advance Cardiac Cryoballoon and Freezor MAX Cardiac Cryoablation Catheter is superior as a first-line treatment for preventing atrial arrhythmia recurrence compared to use of antiarrhythmic drug (AAD) therapy in patients with symptomatic PAF, Medtronic said in a press release.
“The clinical results of STOP AF First demonstrate the superiority of Medtronic cryoablation as a first-line treatment for AF patients, before the disease progresses,” Oussama Wazni, principal investigator for the STOP AF First trial and section head of electrophysiology at the Cleveland Clinic, Cleveland, USA, said.
STOP AF First demonstrated that Medtronic cryoablation was superior in maintaining freedom from AF, atrial tachycardia and atrial flutter, with 75% of patients in the catheter ablation group versus 45% in the AAD group (P<0.001) achieving treatment success at 12 months. A low rate of patient complications occurred when using catheter ablation as a first-line treatment in AF patients who had never received AAD therapy (12-month rate of primary safety events: 1.9%), and the percentage of patients with a serious adverse event was similar between the treatment groups.
Presented as a late-breaking clinical trial at the AHA 2020 with a simultaneous publication in the New England Journal of Medicine, the findings from the EARLY AF study also demonstrated the superiority of Arctic Front Cryoballoon ablation compared with AAD treatment for preventing atrial arrhythmia recurrence in treatment-naive patients with PAF.
A total of 303 patients with symptomatic AF who had not yet received treatment were randomised to first-line AAD therapy (149 in treatment arm), or first-line cryoballoon-based pulmonary vein isolation (154 in treatment arm). All patients underwent implantation of the Medtronic Reveal LINQ insertable cardiac monitor for the purpose of continuous arrhythmia monitoring. The primary outcome was measured by the amount of time, after treatment, that it took for patients to experience a recurrence of AF, atrial flutter or atrial tachycardia.
Results from this multicentre investigator-initiated trial found that Medtronic cryoablation was superior in maintaining freedom from AF, atrial tachycardia and atrial flutter, with 57.1% of patients in the catheter ablation group versus 32.2% in the AAD group (absolute difference in recurrence of 24.9%; P<0.001) achieving treatment success at 12 months. Safety events were low in both groups with 4% of AAD patients and 3.3% of catheter ablation patients experiencing a serious adverse event. Additionally, patients treated with Medtronic cryoablation demonstrated improvements in quality of life and arrhythmic symptoms (e.g., fatigue, rapid heartbeat, shortness of breath). The trial was sponsored by Jason Andrade, director of electrophysiology and associate professor at University of British Columbia, Vancouver, Canada.
“These randomised trials provide evidence supporting cryoablation as an initial rhythm control strategy for patients with atrial fibrillation,” said Christopher Granger, professor of medicine, Duke University, Durham, USA. “This is an important advance for our patients.”
Also at AHA 2020, results from the Cryo-FIRST trial were presented, demonstrating that patients with paroxysmal atrial fibrillation who received first-line treatment with Medtronic cryoablation experienced fewer recurrences of symptoms, compared to AAD.
Cryo-FIRST is a randomised, multicentre trial that enrolled 220 patients at 18 sites in nine countries across Europe, Australia and Latin America. Similar to STOP AF First, this trial found that Medtronic cryoablation is superior to AAD therapy for the prevention of atrial arrhythmia recurrence in PAF patients who have not previously been treated with drug therapy.
The Arctic Front Advance Cryoablation System is approved in Europe for the treatment of AF. The US Food and Drug Administration (FDA) recently expanded the indication for Medtronic cryoablation therapy to include treating patients with drug-refractory recurrent, symptomatic persistent atrial fibrillation (episode duration less than six months), in addition to patients with drug-refractory, recurrent, symptomatic paroxysmal AF. Results of the STOP AF First trial have not been reviewed by the FDA.
“The results of these three trials show that Medtronic cryoablation is a viable and even preferable option for patients with paroxysmal atrial fibrillation even prior to initiation of antiarrhythmic drug therapy,” said Rob Kowal, chief medical officer of Cardiac Ablation Solutions at Medtronic. “It’s wonderful for Medtronic cryoablation to attain this level of consistent validation from multiple studies, and the new evidence ultimately will be beneficial for patients and the physicians who treat them.”