No-implant interatrial shunt improves HF symptoms with durability at 1 year
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ATLANTA – A no-implant interatrial shunt improved HF symptoms including exercise capacity, quality of life and NYHA class at 3 and 6 months, a speaker reported.
At the Society for Cardiovascular Angiography and Interventions Scientific Sessions, Colin M. Barker, MD, FSCAI, director of the cardiac catheterization laboratory at Vanderbilt University Medical Center in Nashville, Tennessee, presented multicenter data from three trial programs assessing the no-implant interatrial shunt (Alleviant Medical) for relief of HF symptoms: ALLEVIATE-HF-1, ALLEVIATE-HF-2 and ALLEVIATE HFrEF.
According to the presentation, implanted shunt hardware can limit follow-on transseptal access, inhibit ease of closure and limit septal access for interventions such as paravalvular leak closure (MitraClip), transseptal patent foramen ovale closure, percutaneous left ventricular assist devices, left atrial appendage closure and pulmonary vein interventions.
Using femoral access and following transseptal puncture, the no-implant interatrial shunt system requires an excision via 0.5-second radiofrequency energy for secure tissue capture, with a target shunt diameter of 7 mm.
“Essentially, the tissue that's removed is a circle that has a 7 mm diameter, and it's captured in a way that the device cuts from the left atrium to the right atrium to prevent or avoid any potential embolic complications,” Barker said during a press conference. “There are other devices out there ... and they require implantables as opposed to the Alleviant, where there's no implantable, no hardware or foreign bodies left inside the patient. There's a natural healing process at the rims after the radiofrequency ablation has been done, which provides a safe and durable interatrial septostomy for shunting to alleviate heart failure symptoms.”
Researchers posited that an implant-free shunt may preserve access while retaining the closure option for the future.
For the ALLEVIATE trials, researchers enrolled 30 patients with HF (mean age, 67 years; 18 women) who were NYHA class II, III or ambulatory IV with elevated peak exercise pulmonary capillary wedge pressure (PCWP). Mean left ventricular ejection fraction was 60.1% in patients with HFpEF and 30% in those with HFrEF.
Outcomes of interest were changes in peak supine exercise PCWP, NYHA class, Kansas City Cardiomyopathy Questionnaire (KCCQ) overall summary score, 6-minute walk test and shunt durability.
The procedures were successful in all 30 patients, with no complications or adverse events through 1 month, according to the presentation.
Barker and colleagues observed a significant drop in confirmed peak exercise pressure from baseline to 1 month in three ALLEVIATE analyses (P = .005).
Significant and sustained improvement in quality of life, as assessed by KCCQ score, occurred across the 6 months of follow-up on the ALLEVIATE-HF 1 trial (P at 1 month, 3 months and 6 months < .001) and the 3 months of follow-up in the ALLEVIATE-HF 2 (P at 1 month = .008; P at 3 months = .009) and ALLEVIATE-HFrEF trials (P at 1 month = .044; P at 3 months = .002).
Barker and colleagues observed continued improvement in NYHA class as well as 6-minute walk test distance (P < .001 at 6 months in ALLEVIATE-HF 1; P = .017 at 3 months in ALLEVIATE-HF 2; P = .003 at 3 months in ALLEVIATE-HFrEF) throughout follow up.
Researchers observed 100% shunt patency among all participants with 12 months of follow-up data and confirmed by transesophageal echocardiography and cardiac CT.
“This early data is promising and shows that we are headed down the right path in developing a new safe and effective approach, without the burden of an implant, to help address the unique needs of this large and underserved patient population,” Barker said in a press release.
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Srihari S. Naidu, MD, FACC, FAHA, FSCAI
We have some devices to try to create shunts, but they have a large footprint in the atrium, and that makes it hard to do structural procedures such as mitral valve repair, left atrial appendage closure or anything else you may want to do in the future. The idea with this new technique is to use a radiofrequency catheter that can essentially put a smaller 7 mm hole in the atrium, leaving nothing behind and taking out that tissue. And that, presumably, should improve diastolic HF or HF symptoms due to LA congestion and elevated LA pressure.
Barker and colleagues did a study looking at three cohorts of patients, two cohorts in HFpEF and one cohort in HFrEF, and found that both at rest, but mainly on exertion, the LA pressure was decreased compared with patients without the shunt. This is interesting because these patients should feel better and, sure enough, using the KCCQ, the researchers found that although the patients were pretty debilitated by HF, there was a significant improvement in that score, in all subsets, primarily in patients with HFpEF who had a reasonably higher score than the ones who are very symptomatic.
I thought that was an interesting study with more to come. We need a larger evidence base in that space, but this could be an improvement in the field of HF therapy without leaving anything behind in the heart.
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Barker CM, et al. Featured Clinical Research: Part 2. Presented at: Society for Cardiovascular Angiography and Interventions Scientific Sessions; May 19-22, 2022; Atlanta.
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