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Transcatheter pulmonary valve shows promise at 2 years in early feasibility study
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SAN DIEGO — Two-year data from an early feasibility study show solid valve function and no paravalvular leak after implantation with a transcatheter pulmonary valve in patients with congenital heart disease and right ventricular outflow tract anomalies.
Eighteen patients enrolled in the Harmony Transcatheter Pulmonary Valve (TPV) early feasibility study have now been followed out to 2 years. The self-expanding valve (Harmony, Medtronic) is being studied in congenital heart disease patients born with right ventricular outflow tract anomalies who underwent a surgical repair early in life. Those enrolled had severe pulmonary regurgitation at baseline and a clinical indication for surgical right ventricle to pulmonary artery conduit or bioprosthetic pulmonary valve replacement.
The primary objective of the early feasibility study was to obtain in vivo data to confirm assumptions on loading conditions for future in vitro frame evaluations and secondary objectives included procedural feasibility, safety and valve performance. Up to 20 patients at three centers in Canada and the United States were implanted with the valve from May 2013 to May 2015 for 5-year follow-up. Fifty-five percent were male, the mean age was 27 years and the mean weight was 74 kg. In nearly all cases, the original diagnosis was tetralogy of Fallot. Ninety-five percent of patients had severe pulmonary regurgitation by echo and the mean right ventricular outflow tract gradient was 10 mm Hg.
These patients continued to experience strong hemodynamics, with 86.7% of patients having no/trace pulmonary regurgitation at 2 years. Mean gradients were consistent and stable at 2 years. Mean right ventricular outflow tract gradient by echo was 19.5 mm Hg at 2 years. Matthew J. Gillespie, MD, cardiologist at The Cardiac Center at Children’s Hospital of Philadelphia, noted that this number includes two patients who were treated in the cath lab for obstruction. The researchers reported no paravalvular leak during 2-year follow-up.
“Two-year results from [this] study reveal stable Harmony TPV position, no erosions, good valve function, no paravalvular leak and no additional frame fractures,” Gillespie said during a presentation at the Society for Cardiovascular Angiography and Interventions Scientific Sessions. “There were four adverse events requiring intervention: two patients required explant within 30 days, two patients developed significant neointimal proliferation requiring treatment in the cath lab [and] all others had no significant right ventricular outflow tract obstruction.”
In other results presented, total procedure time was 129 minutes and most patients were discharged after 1 day. Ninety-five percent of patients had the device delivered to the desired location.
The findings build on 1-year feasibility data that were presented at TCT 2016.
“Following the 1-year feasibility outcomes, we are encouraged to see the Harmony valve continues to show positive outcomes for patients 2 years post-implant. We are optimistic that these early outcomes will be a strong indicator of the types of results that we might expect to see from our pivotal study, which is currently enrolling,” Gillespie said in a press release.
Longer-term follow-up is ongoing, Gillespie said.
The Harmony IDE pivotal study is currently underway. The interventional, single-arm study has a planned follow-up of 5 years. The estimated enrollment is 40 patients at 15 sites in Canada, Japan and the United States. Primary outcome measures include freedom from procedure- or device-related mortality at 30 days and percentage of patients with acceptable hemodynamic function at 6 months, defined as mean RVOT gradient 40 mm Hg and pulmonary regurgitant fraction < 20%.
Reference:
Gillespie MJ. Abstracts: Best of the Best. Presented at: Society for Cardiovascular Angiography and Interventions Scientific Sessions; April 25-28, 2018; San Diego.
Disclosure: Gillespie reports he is a consultant and proctor for Medtronic.