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ATLANTA -- Longer-term outcomes with the Harmony transcatheter pulmonary valve appear to be holding up, with no mortality for the populations studied out to 1 year.

Across the 104 patients who had one of these devices implanted for more than 24 hours across the early feasibility, pivotal, and continued access studies, pulmonary regurgitation at 1 year was no worse than trace for 92% and mild or moderate in all the rest.

No patients died from any cause or had endocarditis by that point, Daniel S. Levi, MD, of the University of California Los Angeles, reported at the Society for Cardiovascular Angiography and Interventions meeting here.

Harmony valve recipients "had favorable clinical and hemodynamic outcomes at 1 year, confirming earlier results and demonstrating continued device success across studies and valve types," Levi concluded at the session.

With the two commercially available devices, the original 22-mm diameter device (TPV22) and modified 25-mm version (mTPV25), freedom from important clinical events was high.

The rates from 30 days to 1 year were 95.1% and 89.7%, with the two devices respectively, for the composite of freedom from moderate or worse pulmonary regurgitation, mean right ventricular outflow tract gradient >40 mm Hg, reoperation for device-related reasons, or catheter reintervention other than intraprocedural wire repositioning and balloon angioplasty.

The discontinued prototype version of the TPV25 device showed worse outcomes on that measure, 73.3% at 1 year.

That 89% rate really reflected a few cases that occurred on the learning curve, for example the one case of embolism after placement of an undersized valve and two of the four reinterventions done for the discontinued version that had structural integrity problems, Levi said.

The findings are useful in confirming that valve function remains good despite that steep learning curve, commented session co-moderator Brian H. Morray, MD, of Seattle Children's Hospital.

"If you have an option that's noninvasive, everybody would go for transcatheter as preferred," noted co-moderator Jacqueline Kreutzer, MD, of UPMC Children's Hospital of Pittsburgh.

But given that surgical valves are so low risk, the Harmony valves had a high bar of safety to meet, Morray acknowledged.

"Many of these patients are good surgical candidates, they are adults. They generally had one, maybe two cardiac surgeries in their life. They're young and relatively healthy," he said. "Having a nonsurgical, minimally invasive option reduces your recovery time but also gives you a platform for future transcatheter valves. Over their lifetime, the goal is to really reduce the number of sternotomies they will need. Those procedures carry quite a lot of risk. The ability to reduce that is actually quite impactful."

The study included 21 patients from the early feasibility study, 50 in the Harmony pivotal trial, and 37 from the continued access study. A total of 106 were implanted with a median 2.1-year duration of follow-up.

Altogether, that totaled 42 implanted TPV22 devices, 45 mTPV25 devices, and 19 of the discontinued TPV25 version. Median follow-up ranged from 3.9 years with the 22-mm diameter device to 1.1 years for the newest 25-mm version.

No major stent fractures occurred with the mTPV25 device; one patient required intervention at 1 month in the early feasibility study, for a rate of 2.4% at 1 year. One-year freedom from any stent fracture was 81% in the TPV22 group and 91% in the mTPV25 group.

One case of thrombosis occurred, in a patient in the mTPV25 group (0.9% of the overall cohort).

Study participants were largely adolescents and young adults, with a mean age of 29 years and a mean weight of 76 kg (168 lb) across the studies.

"These porcine pericardial leaflets are behaving the way we want them to behave," Levi said, noting that the few paravalvular leaks seen have tended to get better with time.

There are still refinements being made, he noted, for example device positioning has tended to move higher to avoid issues with arrhythmia. Ventricular tachycardia occurred in 17.6% of the overall cohort, but no cases were sustained.

Another question is even longer-term outcomes, Morray added. "One year follow-up would still be early for endocarditis evaluation. There's more to come on that."

Follow-up will continue through 10 years, but there are efforts underway to develop registries to follow these patients even longer, said Morray. "It's important to understand how well they do as they get older."

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