No-Implant Shunt Eases HF Symptoms in Early Data

ATLANTA -- Creating a left-to-right shunt in the interatrial septum to offload failing hearts was associated with improved quality of life and symptoms in a series of small feasibility studies.

Peak pulmonary capillary wedge pressure during exercise decreased significantly from baseline to 1 month after the procedure among the 15 patients in the ALLEVIATE-HF-1 study of heart failure with preserved or mid-range ejection fraction (>40%) with mild to moderate functional limitation.

A consistent numerical signal, albeit not significant, on that measure was seen in a similar group of 11 patients in the ALLEVIATE-HF-2 study and in the five patients with heart failure with reduced ejection fraction (<40%) in the ALLEVIATE-HFrEF study.

But across all three studies, quality of life as measured by the Kansas City Cardiomyopathy Questionnaire improved significantly on the order of 20 points on the 100-point scale by 1 month, sustained at 3 months, and out to 6 months in the one that had longer follow-up.

"Just as important is how patients feel," said Colin M. Barker, MD, director of the cardiac cath lab at Vanderbilt University Medical Center in Nashville, who called the symptom improvements "very significant."

New York Heart Association functional class improved from typically Class 3 to Class 1 or 2, he reported here at the Society for Cardiovascular Angiography and Interventions meeting.

Six-minute walk test results improved significantly and steadily to roughly 300 to 350 meters across the studies.

The shunt appeared durable, with 100% patency through 12 months in the 10 patients with available transthoracic echocardiography and CT scans.

"It's not very exotic but very effective. What it does is create a very predictable, reproducible atrial septostomy with the intent and goal of unloading the volume and pressure in patients with heart failure and alleviating them of their symptoms," he said.

The device uses radiofrequency to create a 7-mm diameter shunt, "almost a biopsy," Barker said, from the left atrium to right atrium. That circle of excised tissue is captured by the device to prevent embolic complications.

Other devices to create a similar shunt to treat heart failure, such as those in the works from Corvia and V-wave, rely on implanted hardware, he noted, whereas the Alleviant Medical device doesn't leave behind any hardware or foreign body that could impact septal access for future transseptal interventions.

"This approach to try to unload the left atrium is novel but becoming well accepted in advanced heart failure populations," SCAI past president Kirk Garratt, MD, MSc, of the Christiana Care Health System Center for Heart and Vascular Health in Newark, Delaware, told MedPage Today at a press conference.

"There remain questions about long-term consequences of an intentional interarterial shunt, what that does to pulmonary flow dynamics and the like," he added. "But to date the impact of this approach has been favorable."

It's especially notable for inclusion of HFpEF, a "terrible beast" for which few drug therapies have proven effective, Garratt said.

The shunt strategy is not likely to lengthen life for patients, but it does have an "incredibly reassuring" safety profile, Barker noted.

There have been no technical or procedural failures or any major adverse cerebrovascular or cardiovascular adverse events or thromboembolic events through 1 month.

While there haven't yet been cases where the shunt created has been closed, it's similar to an atrial septal defect, Barker said, and plenty of experience closing those shunts suggests a way to close them if need be.

Nor has there so far been a need to enlarge any of the holes, he said. "As of now it's one size, but you could imagine one-size-fits-all is ultimately probably not the way this will go."

The engineers are devising an adjustable mechanism to customize the size, Barker said. "What we do is calculate a predicted shunt ratio that falls within a safe shunt range so we don't overwhelm the right side of the heart."

Patients were selected based on exercise hemodynamics (with measurements taken during a leg lift and reclined cycling), which Barker predicted will be important for the future success of the procedure in the sham-controlled pivotal trial anticipated to start this year.

He pointed to the REDUCE LAP-HF II trial, in which the Corvia shunt device did not reduce the total rate of heart failure events or improve health status in patients with heart failure and ejection fraction of greater than or equal to 40%, despite selecting patients with pulmonary capillary wedge pressure during exercise of at least 25 mm Hg while exceeding right atrial pressure by at least 5 mm Hg.

If the approach does succeed, he said at the featured clinical research session that he could see most advanced heart failure patients being candidates for what is essentially an easy 10-minute procedure, with patient selection driven by heart failure specialists. "We're the technicians," he said.

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