Ultralow temperature cryoablation using near‐critical nitrogen for cavotricuspid isthmus‐ablation, first‐in‐human results

Abstract

Introduction: Cryoablation has evolved as a safe alternative to radiofrequency ablation in the treatment of several supraventricular arrhythmias and has potential advantages, yet is limited by the properties of the cryogen used. We investigated a novel ultralow temperature cryoablation (ULTC) system using nitrogen near its liquid-vapor critical point as a freezing source, achieving temperatures as low as -196 degrees Celsius in a long linear catheter with a continuous energy release. Initial safety, procedural and efficacy outcomes of ULTC are described in patients undergoing cavotricuspid isthmus (CTI) ablation. Methods and Results:The Cryocure studies (NCT02355106, NCT02839304) are prospective, single-arm, multi-center, first-in-human clinical studies in 17 patients with atrial flutter (AFL) and 13 patients with atrial fibrillation (AF). A total of 30 patients, mean age 65 ± 8 years old and 67% male, were enrolled and underwent ablation of the CTI. Acute success, defined as the confirmation of stable bidirectional conduction block across the CTI, was achieved in all 30 patients. After 12 months of follow-up, 14 out of 17 AFL patients remained free from any AFL. One (3.3%) procedure-related but not devicerelated serious adverse event was reported, involving transient inferolateral ST-elevation associated with temporary AV conduction block. Conclusion:In this first-in-human clinical study the safety and performance results demonstrate the capabilities of ultralow temperature near-critical nitrogen as an effective energy source for CTI ablation. Ongoing, larger, studies should confirm our findings and evaluate the capabilities to create linear and focal transmural lesions in other arrhythmias.This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.

A “Scalpel” for interventional electrophysiologists

“…This provided a cryogen with the viscosity of gas that can be delivered through extremely small tubes at a temperature of −196°C, making it feasible as a cryogen for use in ablation catheters. The clinical results reported by Klaver et al 9 in this issue of JCE confirm the promise of this new approach for the catheter treatment of atrial fibrillation.…”

“…The cryocatheter used in the clinical study reported by Klaver et al 9 was developed by Adagio Medical, Inc., which was founded in 2010 with one specific goal … to provide interventional electrophysiologists (EP's) with a tool that would allow them to perform catheter ablation for atrial fibrillation with the same flexibility and efficacy that surgeons have with surgical instruments. We theorized that if we could provide EP's with the equivalent of a surgical scalpel, they could potentially treat atrial fibrillation with the same results that we routinely attained with the open‐heart Maze procedure.…”

“…After several visits to Baust's laboratory and a few experiments using irreversible electroporation (pulsed‐field ablation, or “PFA”) in Professor Boris Rubinsky's laboratory at the University of California, Berkley in the summer of 2010, we chose to pursue the adaptation of ultra‐low cryosurgery as the most promising new energy source for the catheter ablation of atrial fibrillation. About a year later, we were fortunate to recruit Dr. Alex Babkin, a former NASA engineer and an expert in cryothermia, as our chief engineer at Adagio Medical and over the next 10 years Dr. Babkin and his colleagues at Adagio Medical developed the ultra‐low cryocatheter that is described in the accompanying article by Klaver et al 9 After some 8 years of animal research and catheter development, we invited Dr. Tom de Potter and later, Dr. Lukas Boersma, to perform the first clinical cases using the Adagio ultra‐low cryocatheter. We chose to use it first to create simple cavo‐tricuspid isthmus lesions in patients with atrial flutter because of the simplicity of the abnormal electrophysiology and its interventional treatment.…”

Preventing esophageal complications from atrial fibrillation ablation: A review

“…The main published clinical evaluation using this technology so far has been to treat atrial flutter. 77 Although acute success was obtained in 100% (17 patients), only 82.4% remained free from atrial flutter after 12 months of follow-up, which is a lower long-term success rate compared to established ablation methods. 78 However, as the technology is new, there is scope for improvement.…”

Initial clinical experience of pulmonary vein isolation using the ultra‐low temperature cryoablation catheter for patients with atrial fibrillation

“…In spite of various potential prospects, the data on in-human clinical experience in AF ablation using this modality has been limited. 6,7 In this study, we describe the initial clinical experience using ULTC for patients with AF.…”