The Luminize (Boston Scientific) radiofrequency balloon catheter is safe and effective at 30 days in the treatment of atrial fibrillation, data from the AF-FICIENT I study has shown. Amin Al-Ahmad (Texas Cardiac Arrhythmia Institute, Austin, TX, USA) presented the findings on behalf of the investigators in a late-breaking trial session at the European Heart Rhythm Association (EHRA 2019; 17–19 March) congress in Lisbon, Portugal.
He said: “In the AF-FICIENT I trial, the Luminize radiofrequency catheter achieved high rates of pulmonary vein isolation, with very short total ablation times, and low rates of device-related complications. Device enhancements led to a shorter procedure time, as well as less radiofrequency applications.”
The balloon catheter uses radiofrequency energy to isolate the areas of the heart muscle responsible for the abnormal heart rhythm. The single-shot catheter also features built-in digital cameras for visual guidance, sensing electrodes on the balloon to assess real-time vein isolation and customisable ablation electrodes with the ability to deliver tailored levels of energy around the circumference of the balloon.
The AF-FICIENT trial was a prospective, non-randomised, multicentre pilot study that assessed the safety and performance of the system in isolating pulmonary veins for the treatment of paroxysmal atrial fibrillation. It took part in two phases, with phase I (n=18) testing the original design of the balloon device.
Following this stage, Al-Ahmad explained: “There were further device enhancements, based on that early experience. These enhancements included increasing steerability of the sheath, as well as addition of the electrodes on the catheter that would allow sensing of the signal.”
The phase II device was then used on a further 81 participants. The primary safety endpoint was acute safety at 30 days, and the primary performance endpoint looked at the rate of successful pulmonary vein isolation with confirmed block. Confirmation was completed with the radiofrequency balloon sensing electrodes, a circular mapping catheter, or both. The average age in both phases was 58 years, 68% of subjects were male, and 78% of those in phase I had paroxysmal atrial fibrillation compared to 100% of those in phase II.
Al-Ahmad told delegates: “The procedure time dramatically improved after device enhancements were made, from an average of 173 minutes down to an average of 79 minutes. This reflects both the device enhancements, and experience with the device. Balloon dwell time also improved dramatically, from approximately 100 minutes to 33 minutes. Fluoroscopy time improved as well—from approximately 43 minutes to 14 minutes—with phase II enhancements.”
There were no device-related serious adverse events in either phase at 30 days post-procedure, and in patients with available cardiac imaging there were no cases of pulmonary vein stenosis (0/32). Successful pulmonary vein isolation was achieved in 88.9% (64/72) of veins in phase I. In phase II, pulmonary vein isolation increased to 99.4% of veins (322/324). By patient, 77.8% (14/18) of those in phase I and 97.5% (79/81) of subjects in phase II had successful isolation of all pulmonary veins. In phase I, there were 12 applications per patient; phase II had eight applications, approximating to two applications per vein.
Al-Ahmad acknowledged that a limitation of the findings was the lack of long-term data looking at freedom from atrial fibrillation. He said: “Further data are needed to understand the time to effect, time to isolation, and how that will impact dosing, as well as freedom from arrhythmia.”
