Scientists now report that cryoablation effectively closes congenital patent foramen ovale (PFO, a small hole in the heart) in patients with atrial fibrillation (AF) undergoing pulmonary vein isolation (PVI) in a one-time procedure, with no complications.
A new study published in Heart Rhythm details an alternative method for PFO closure, describing the adverse events associated with the conventional approach, which involves implanting a percutaneous metal device. These adverse events consist of complications such as infection and arrhythmia. PFO is present in 20% to 34% of adults and is associated with various conditions such as transient ischemic attack (TIA), cryptogenic stroke, migraine, and decompression sickness.
Percutaneous device occlusion is the current standard treatment for PFO-associated ischemic stroke. Though, this permanent device poses various risks such as infection, pericardial effusion, device displacement, thrombus formation, and arrhythmia during implantation. Additionally, the presence of a metal occluder can obstruct future interventional access to the left atrium, and cause difficulties in procedures such as catheter ablation for atrial fibrillation (AF), mitral valve clamping, and left atrial appendage occlusion.
The first use of cryoablation, a minimally invasive procedure that supercools tissue and selectively kills blood vessels, to induce PFO closure is presented in this study. “Our purpose was to evaluate cryoablation without implantation for closure of the PFO in patients with atrial fibrillation undergoing PVI. We hypothesized that cryoablation can also close PFO by injuring the primary and secondary septum. It is very difficult to say whether PFO is responsible for the stroke when AF and PFO occur simultaneously, as AF and PFO both are risk factors for stroke/TIA. The benefits of PVI in combination with PFO closure are not known. We aimed to determine whether atrial septal (AS) cryoablation in isolates with AF could induce closure of a PFO to outcomes,” said one of the lead investigators EnRun Wang, department of cardiovascular medicine, Yongchuan Hospital of Chongqing Medical University, China.
The study compared two groups of patients (N=22) with PFO and AF undergoing PVI through cryoablation. Group 1 (n=11) underwent additional AS cryoablation, while Group 2 (n=11) received a sham procedure. At 6 months, the PFO closure rate was significantly higher in Group 1 (63.6%) compared to Group 2 (9.1%, P = 0.002). AF recurrence rates were comparable between the groups at 3 months (27.3% vs 9.1%, P = 0.269), 6 months (0 vs 0), and 12 months (18.2% vs 9.1%, P = 0.534). No ischemic strokes were reported at 1-year follow-up. The authors concluded that cryoablation offers a safe and effective method for closing PFO in AF patients undergoing PVI in a single procedure.
The potential benefits of the notion of a ‘no footprint,’ device-free, percutaneous PFO closure are described in an accompanying editorial commentary written by Nir Flint, MD division of cardiology, Tel Aviv Sourasky Medical Center, Tel Aviv University School of Medicine, Tel Aviv, Israel.
Physiologically, this procedure simulates the physiologic healing and closure of the PFO by inducing inflammation, scarring, and anatomic closure of the interatrial septum. In this approach, the adverse events from artificial materials are minimized and there is scope for future interventions in case of requirement.
The authors wisely used this procedure on people having ablation of AF with a closing-the-door-on-the-way-out approach. The preliminary results are promising, but the efficacy needs to be checked and improved along with the safety. This will need additional research. However, this technique may open the way for new strategies for PFO management for those patients who undergo ablation procedures.
Reference: Deng J, Wang E, Liu G, et al. Feasibility and safety of cryoballoon ablation for atrial fibrillation and closing patent foramen ovale without implantation: A pilot study. Heart Rhythm. 2024;21(12):2460-2467. doi:10.1016/j.hrthm.2024.06.006‌
