AVATAR-HF: Simplified AF ablation yields good outcomes for less costs

Foregoing intracardiac electrophysiologic mapping was as good as conventional cryoablation with pulmonary vein (PV) mapping in the AVATAR-HF* study, suggesting that a simplified procedure could produce the same outcomes for lower costs. 

Considering that it was a day-case cryoablation, this also means fewer patients with atrial fibrillation (AF) on the waiting lists. On top of that, AF ablation without PV mapping was superior to antiarrhythmic drugs during 1-year follow-up, reported Dr Prapa Kanagaratnam, principal investigator and consultant cardiologist at Imperial College Healthcare NHS Trust, London, UK.

Patients in the AVATAR-AF trial were randomly assigned to AF ablation without PV mapping (AVATAR group, n=110), medical therapy group (anti-arrhythmic group, n=103), or conventional cryoablation using mapping (conventional group, n=108). Mean age of the patients was 60 years, majority of them were male, with CHA₂DS₂VASC scores largely in the 0–3 range and mean left ventricular ejection fraction of 57–58 percent. [EHRA 2019, abstract LBT1-176]

About 40 percent of patients were taking a class I/III anti-arrhythmic agent, 63–74 percent were on anticoagulants. The AVATAR protocol involved anticoagulation based on guidelines using the CHA₂DS₂VASC score, sedation or general anaesthesia, transeptal puncture by a catheter, and balloon occlusion of the PV with two 3-minute cryoblations. There was phrenic nerve monitoring using a temporary transvenous pacing wire but there was no specialist electrophysiology catheters or PV isolation assessment done.

Patients who were asymptomatic or had improvement in symptoms were discharged from hospital-based specialist care at 12 weeks and followed at 6, 9, and 12 months. At 1 year, the AVATAR protocol was superior to antiarrhythmic therapy in terms of hospital episodes related to treatment for atrial arrhythmia. There was a significant difference with 23 events in the AVATAR arm vs 76 in the antiarrhythmic arm (p<0.001).

And given the noninferiority of the AVATAR protocol to conventional cryoablation, Kanagaratnam believed it is possible to simplify AF ablation procedures without compromising outcomes. The findings also question two things — the value of drug therapy and whether catheter ablation should be the first-line treatment for AF patients with symptoms, said Kanagaratnam.

Study discussant Dr Jose Merino from the La Paz University Hospital in Madrid, Spain said if mapping can be avoided in future, any catheterization laboratory could do cryoablation. EHRA president and session comoderator Dr Hein Heidbuchel from Antwerp University, Belgium commented that it was “an intriguing and unexpected finding” that the outcomes were similar for the two procedures.

“Interventionists are all struggling to find easier ways to isolate the pulmonary veins. I don’t think AVATAR-AF will be the groundbreaking trial facilitating that …”