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Finally, a Transcatheter Solution for Native Outflow Tracts
Pulmonary valvotomy and other surgeries involving the right ventricular outflow tract (RVOT) can save children’s lives, but often come with an unfortunate side effect: pulmonary regurgitation that requires valve replacement. Making matters worse, the outflow tracts can be too large to accommodate currently available transcatheter valves, which means patients must endure open-heart surgeries to implant artificial valves and replace them as they age.
Fortunately, an innovative device – the Edwards Alterra Adaptive Prestent – could change the game. This self-expanding, stent-like device can be inserted into the outflow tract to downsize the outflow tract and create a “landing zone” that enables transcatheter valve placement, sparing children and adults with pulmonary regurgitation from a lifetime of invasive surgeries.
Faster, Safer Valve Replacement
Children’s Health℠ was one of four sites in a Phase I trial of the new device, which has a nitinol, hourglass-shaped frame to help anchor it in place. The Alterra leaves a row of cells uncovered at the outflow end to prevent blockage of (obstruction of) flow to the branch pulmonary arteries. The Alterra is deployed via catheter, and then the SAPIEN 3 Transcatheter Heart Valve System is advanced through the same sheath and guidewire, and placed inside the Alterra.
The procedure usually takes about two hours. Most children spend one night in the hospital and are back to normal activities within three days – much faster than the four- to six-week recoveries that go along with open-heart surgery.
“Procedures like pulmonary valvotomy can mean a lifetime of follow-up surgeries and potential complications,” says Vivian Dimas, M.D., Director of Interventional Cardiology at Children’s Medical Center Dallas and Associate Professor of Pediatrics at UT Southwestern Medical Center. “I’m hopeful that Alterra could make some of those surgeries obsolete and help more patients thrive.”
Dr. Dimas is the Alterra trial’s site principal investigator and is presenting the study’s 6-month follow-up data on behalf of the investigators at the annual Scientific Session of the SCAI. The trial demonstrated safety and efficacy of placement of the prestent and valve with no significant complication.
For example, our first patient in the trial – a 16-year-old girl named Angelica – was born with severe narrowing of her pulmonary valve and the area below it, as well as several holes in her heart. When she was 7 months old, a patch was placed across her pulmonary outflow, resulting in leaking or insufficiency of the pulmonary valve. Over time, she became increasingly fatigued by activity, and her right ventricle began to show signs of stress.
After the procedure, she noticed an immediate improvement – she could walk across the room without feeling winded. At her 6-month visit, she reported feeling “better than she ever had.” It’s now been almost a year, and she continues to do well.
Developing Breakthrough Devices
The Alterra trial is just the latest step in our push to bring the next generation of innovative devices to children with a range of heart issues. For example, Dr. Dimas helped pioneer the use of Impella percutaneous left ventricular assist devices – which are among the world’s smallest heart pumps – in kids. She also worked with Impella’s manufacturer to develop a version tailored to children.
We’re currently participating in more than three clinical trials of new devices.
“Parents give me the opportunity to take care of their most prized possession, and some of them have to do that over and over,” says Dr. Dimas. “That’s the impetus behind my research -- to figure out how to make heart procedures less invasive, with faster recoveries, so children can get back on track toward happy, healthy lives.”
Children’s Health surgeons perform nearly 750 cardiac catheterization procedures a year. This expertise, combined with our team of world-class subspecialists, helps explain why U.S. News and World Report ranks our Heart Center #17 in the nation.