New research shows that cryoablation is a safe and effective approach to close congenital patent foramen ovale (PFO, a small hole in the heart) in patients with atrial fibrillation (AF) undergoing pulmonary vein isolation (PVI) in a single procedure. A new study in Heart Rhythm, the official journal of the Heart Rhythm Society, the Cardiac Electrophysiology Society, and the Pediatric & Congenital Electrophysiology Society, published by Elsevier, details this alternative method to the conventional treatment of implementing a percutaneous metal device for PFO closure, which is associated with adverse events such as infection and arrhythmia.

In adults, the prevalence of PFO ranges between 20% and 34%. PFO is associated with a variety of disorders, including cryptogenic stroke, transient ischemic attack (TIA), migraine, and decompression sickness. Percutaneous device occlusion is currently the standard therapeutic option for PFO-related ischemic stroke. However, there are risks associated with implantation of this permanent device, including infection, pericardial effusion, device displacement, thrombus development, and arrhythmia. Furthermore, a metal occluder would obstruct future access to the left atrium in interventional treatments such as catheter ablation for AF, mitral valve clamping, and left atrial appendage occlusion.

This study presents the first use of cryoablation, a minimally invasive procedure that uses extreme cold, to induce PFO closure.

Co-lead investigator of the study Jiang Deng, MMed, Department of Cardiovascular Medicine, Yongchuan Hospital of Chongqing Medical University, Chongqing, China, notes, "The pursuit of an ideal PFO closure method without a residual device is a compelling endeavor. Our aim was to investigate the efficacy and safety of PFO closure using cryoablation without implantation in patients with atrial fibrillation who underwent PVI. We postulated that cryoablation can also fuse PFO by injuring the primary and secondary septum."

Co-lead investigator EnRun Wang, MMed, Department of Cardiovascular Medicine, The First Affiliated Hospital of Chongqing Medical University, Chongqing, China, explains, "Although AF and PFO are both risk factors for stroke/TIA, it is difficult to determine whether PFO is involved in the development of stroke when the two disorders co-occur. The advantages of PVI in conjunction with PFO closure are unknown. Our aim was to investigate whether atrial septal (AS) cryoablation could lead to secondary PFO closure in individuals with AF who undergo PVI."

The study enrolled a group of 22 patients with symptomatic drug-refractory paroxysmal or short-time persistent AF and PFO who were admitted for PVI via cryoablation from the First Hospital of Chongqing Medical University. Eligible patients were divided into the standard PVI + AS cryoablation group and the standard PVI group. The research was designed to determine the PFO closure rate, procedure-related complications, the recurrence of AF, and stroke/TIA events. Patients who underwent AS cryoablation had a significantly higher rate of successful PFO closure than individuals who only had balloon inflation. There was no difference in procedure-related adverse events, AF recurrence, and ischemic stroke/TIA events in both groups.

Nir Flint, MD, Division of Cardiology, Tel Aviv Sourasky Medical Center and Tel Aviv University School of Medicine, Tel Aviv, Israel, coauthor of an accompanying editorial commentary, notes, "The notion of a ‘no footprint,’ device-free, percutaneous PFO closure presents potential benefits. This procedure theoretically mimics the physiologic healing and closure of the PFO by inducing inflammation and scarring, creating an anatomic closure of the interatrial septum. This approach minimizes the adverse events associated with artificial materials and allows future interventions if needed."

Eyal Ben-Assa, MD, Division of Cardiology, Assuta Ashdod University Hospital and Ben Gurion University, Ashdod, Israel, coauthor of the commentary, concludes, "This study presents an innovative approach to PFO closure by cryoballoon ablation, showcasing its potential as a device-free alternative. The authors wisely performed this procedure on patients undergoing ablation of AF with a closing-the-door-on-your-way-out approach. Whereas preliminary results are promising, further research is needed to enhance efficacy and to confirm safety. This technique could pave the way for new strategies in PFO management, particularly for patients undergoing ablation procedures."