The first-in-human results are “an encouraging first step with a new ablation source,” says one expert.
BERLIN, GERMANY—Treatment of monomorphic ventricular tachycardia (VT) with a novel ultra-cold cryoablation catheter (vCLAS, Adagio Medical) is safe and effective in patients with ischemic or non-ischemic cardiomyopathy According to the results of the first-in study, this is true. -Human Cryocure-VT study.
There were no protocol-defined serious adverse events related to the device or the procedure, and there were positive acute outcomes in terms of eliminating ventricular tachycardia, said Atul Verma, MD, PhD, McGill University Health, Montreal, Canada. Center) reported in European Heart Rhythm earlier this week. Association Conference 2024.
Additionally, by 6 months, 60.3% of patients did not have ventricular tachycardia lasting >30 seconds and 81.0% did not receive an implantable cardioverter defibrillator (ICD) shock.
These results were published simultaneously online. EP Europe, which was consistent with the results of previous important VT studies, Verma reported. “Further post-marketing studies are required and additional studies are ongoing including: Fulcrum-VT“This will be a very important American trial,” he said.
Discussant after Verma’s presentation, Dr. Usha Tedrow (Brigham and Women’s Hospital, Boston, Massachusetts), noted that improving the success rate of VT ablation is desired. Currently, the usage rate of radiofrequency catheters is approximately 60%. There are challenges with regard to mapping, as identification of functional and intramural stroma is difficult, and with respect to ablation, radiofrequency catheters have problems with fibrosis, calcification, chronic thrombosis, and intramural scarring. she stated.
“We need a powerful yet titratable energy source that can be used to reach the deep matrix within the wall without collateral damage,” Tedrow said.
Considering whether the cryoablation system studied here is the answer, she noted that while the 60% VT recurrence rate was consistent with previous studies, the burden of VT was reduced “very significantly.” .
Safety and efficacy are “reasonable,” she said, adding: “It would be very interesting to see the results with more image-assisted substrate guidance that could help increase success rates.” he added.
Overall, Dr. Tedlow concluded, “This is an encouraging first step with a new ablation source.”
Cryocure-VT research
VT ablation remains a “thorny problem” when using radiofrequency energy, Verma said, noting that scar tissue results in shallower lesion depths, normal tissue has limited lesion depth, and cardiomyopathy We noted that complications persist in patients.
He said changing the energy source for ablation could help improve the situation. ultra-low temperature cryoablation, Obtained CE mark approval in Europe The technology, developed last month for the treatment of VT, is still in the research phase in the U.S., but is notable for employing supercritical fluid nitrogen, which prevents vapor lock and allows delivery through smaller lumen catheters. It is different from traditional cryoablation.
“So this is a really important solution,” Verma said, adding that this type of ablation can penetrate both scar and normal tissue, and the depth of the lesion depends on the length of the freeze. .
Cryocure-VT, performed at nine centers, was performed on 64 adult patients (mean age 67 years; This was the first human clinical trial of this system in subjects (95.3% male). VT. All patients were refractory to at least one of her antiarrhythmic drugs and received her ICD before discharge.
The mean LVEF of the patients was 35%. The majority (79%) had ischemic cardiomyopathy and the remainder had non-ischemic substrate.
In this procedure, intracardiac echocardiography was used in 68.8% of cases. The average surgical time was 188 minutes, “which is a fairly reasonable time for a VT ablation procedure for scar-based cardiomyopathy,” he said. The average number of lesions per patient was 8.9 and the average freezing time per lesion was 3.8 minutes.
Acute results were “very good,” Verma reported. The primary success rate (no induced clinical VT) was 94.4%, and the secondary success rate (no induced VT of any kind) was 85.2%. Over 97% of his clinical VT was removed.
Six-month outcomes in terms of recurrent persistent monomorphic VT or not receiving adequate ICD therapy were similar regardless of the type of underlying cardiomyopathy. In patients who had an ICD for at least 6 months before ablation, VT burden decreased from his median of 4 ICD events to 0.
From a safety perspective, there were no device- or procedure-related serious adverse events within 30 days after ablation, but four serious adverse events occurred. Namely, there were 2 cases of minor/small pericardial effusion (3.1%) and 1 case of 2 mm asymptomatic pseudoaneurysm. tissue damage (1.6%), and one case of intraprocedural hemodynamic instability that required extracorporeal membrane oxygenation support (1.6%). All cases resolved without clinical sequelae.
Further research required
Commenting on the TCTMD results, Dr. KR Julian Chun (Bethanien Center for Cardiovascular Medicine, Frankfurt, Germany) said: And it’s dose-dependent by freezing duration, so it could be an interesting device to really get deep lesions. ”
The technique may be particularly useful in treating certain types of premature ventricular complexes, such as papillary muscles, because it increases stability when the catheter is attached to tissue, Chun said.
He said his team plans to run some cases using the system soon, but added that these data are very preliminary. “We need to learn more,” he said. “We need to see how this works within a 3D mapping system…because of course we need to understand where we’re ablating and where the substrate is.”
Professor Tedlow also said that although safety was reasonable in this study, the occurrence of asymptomatic pseudoaneurysms in very thin tissue was a potential concern. “We don’t know if we would have done routine imaging of all patients if something had happened. . . . We would see something similar in more patients.”
He also noted that more information is needed about the mechanism of the observed ventricular tachycardia recurrence.