In this article, we provide information on the clinical trial evaluating the Toray Satake Balloon Thermal Ablation System at Beaumont Hospital. EP Lab Digest® speaks with David Haines, MD, director of Beaumont Hospital’s Heart Rhythm Center and national principal investigator of the research study testing the safety and effectiveness of the device.
Tell us about the Toray Satake Balloon (TSB) Thermal Ablation System.
The TSB thermal ablation system is designed for ablation of pulmonary veins in patients with paroxysmal atrial fibrillation. The catheter for this system has a compliant balloon that can be deflated for insertion through a 14 French sheath, and reinflated in the left atrium for positioning at the pulmonary vein ostia as well as at the antral level. Because the balloon is compliant, it conforms to the unique anatomical features of the individual pulmonary veins. In addition, depending upon the volume of saline/contrast injected into the balloon, the balloon profile can be small or large. Thus, it is fairly easy to achieve pulmonary vein occlusion and circumferential contact of the balloon wall to the atrial, antral or vein wall. Once the balloon is inflated and positioned, radiofrequency energy is delivered to a single electrode within the balloon. The saline/contrast solution within the balloon is heated, that heat is transmitted to the balloon surface, and the hot balloon subsequently heats the tissue. The system is designed to create a transmural circumferential lesion achieving vein isolation with relative ease and time efficiency with a minimal risk profile similar to pulmonary vein isolation procedures using standard techniques.
How does the Toray hot balloon treat atrial fibrillation?
The TSB hot balloon is a technology designed to create electrical isolation of the pulmonary vein and antral myocardium from the rest of the left atrium. It is thought that most of the triggers accounting for paroxysmal atrial fibrillation arise from pulmonary vein and antral myocardial tissues. By electrically isolating these tissues from the remainder of the heart, they can no longer trigger the atrium into fibrillation.
Beaumont Health System was recently selected as the first center outside of Japan to use this new balloon ablation technology. How did Beaumont Hospital become involved in this trial?
I have been involved in the development and testing of the TSB hot balloon ablation system for many years. I participated in the preclinical testing of this device to obtain FDA approval to proceed with human trials. I have worked with the sponsor to develop the clinical testing protocol for patients in the United States. I am the principal investigator for the U.S.-based trial.
What is the purpose of the clinical study? Describe the trial objectives.
Presently, we are testing the TSB hot balloon ablation system in an FDA-approved pilot study of 35 patients at four U.S. centers. In this initial trial, we will gain experience with this technology in human patients and prepare for more definitive testing in a pivotal trial. These FDA-supervised investigations, if successful, will ultimately lead to consideration of approval of this device for general use in the United States.
What is the target patient population for the study? What other sites are participating?
Presently, patients with symptomatic paroxysmal atrial fibrillation who have failed at least one drug are potential candidates for this trial. In addition to Beaumont Health System, three other centers are participating (Mount Sinai Hospital, New York, NY; St. David’s Medical Center, Austin, TX; and the Medical University of South Carolina, Charleston, SC).
How many patients have been enrolled in the clinical trial thus far? When did enrollment begin?
Presently, six patients have undergone the procedure, and a number of patients are enrolled and scheduled for procedures in the near future.
How does this technology compare with other balloon catheters currently available? What advantages does this balloon offer over current treatments for AF?
The main difference between the TSB hot balloon ablation catheter and other balloon-based ablation systems is that the TSB balloon is very compliant, designed to easily conform to variations in the pulmonary vein anatomy and optimize thermal energy delivery to the tissue. The energy delivery is highly controllable since it is a pure thermal ablation technology (there is no direct RF energy administered to the tissue). Because of this, the highest temperature in the system is the temperature recorded in the center of the balloon, and should avoid inadvertent superheating of deep tissue structures (such as the esophagus). We anticipate that we will be able to achieve a therapeutic ablation of the pulmonary vein antral tissue and minimize collateral injury with expected risks similar to those encountered when using standard pulmonary vein isolation techniques.
What is the estimated completion date for this trial?
It is anticipated that enrollment for the pilot phase of this trial will be completed within four months, and that follow-up will be completed 12 months after the last patient is enrolled.
Is there anything else you’d like to add?
Like any new technology, we believe that the TSB hot balloon ablation system may offer advantages that will translate into improved procedural success and decreased procedural complication rate. However, those hypotheses remained untested in U.S. patients, and the purpose of the trial is to investigate these very questions. We look forward to collecting our data and reporting our outcomes to the scientific community.
Disclosure: Dr. Haines reports grant support for the clinical trial, honoraria, and travel/accommodations expenses covered or reimbursed to his institution from Toray Medical, Inc.