Late and early results in tune with Melody and Harmony transcatheter PVs

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At SCAI 2020, researchers shared 10 years of data on a long-standing device and 6 months for a more recent arrival.

Two reports, covering two different pulmonary valves per catheter for separate but related indications, provide reassurance that an evolving field is heading in the right direction, with options extending to a wider population of patients with congenital heart disease .

Transcatheter pulmonary valves (TPV) placed in an existing dysfunctional right ventricular outlet (RVOT) or bioprosthetic pulmonary valve show good long-term results, according to the 10-year follow-up of the Experimental Device Exemption (IDE) Melody (Medtronic) test.

For the Harmony transcatheter pulmonary valve (Medtronic), 6-month data from the pivotal trial shows positive signs for a target that has proven to be more elusive: pulmonary regurgitation (RP) in patients who have undergone RVOT surgery for congenital heart disease but has not received a valve or prior conduit.

Both reports were published at the 2020 Virtual Meeting of the Society for Cardiovascular Angiography and Interventions (SCAI).

Thomas K. Jones, MD (Seattle Children’s Hospital, WA), who presented the Melody IDE data, told TCTMD that in 2000, the device was the first transcatheter valve to be implanted in a human patient.

“One of the festive aspects of all of this is that [Melody] represents a new paradigm in cardiac treatment which has now [grown into] this explosive number of patients treated worldwide, in particular for aortic valve disease. But it all started with the congenital heart population in the treatment of pulmonary valve position, ”he commented. As such, “this is the first and only long-term study of catheter-based heart valves ever to be performed. Ten-year data is difficult to obtain, and forward-looking 10-year data is important. “

Christopher J. Petit, MD (Children’s Healthcare of Atlanta, GA), agreed that long-term follow-up is welcome. For clinicians who have implanted Melody valves over the years and have tracked their results, “there has always been a kind of understanding of how our patients are doing. But certainly overall to have this data and to have the entirety of all the initial 171 patients who were enrolled 10 years later, it’s very useful, ”he told TCTMD.

Melody IDE Trial

For the Melody IDE trial, researchers recruited 150 patients with a median age of 19 (47% were under 18). Half had originally been diagnosed with tetralogy of Fallot. Pulmonary insufficiency was the main indication for 53%, RVOT obstruction for 26% and a combination of the two for 21%.

By 10 years, 90% of these patients had survived. Most (73%) had no or traces of RP, while 25% and 3% had mild or moderate RP, respectively. An even higher percentage belonged to NYHA functional class I (78%), with 22% in class II. The absence of repeat surgery was 79% and the absence of reoperation by catheter was 72%.

The primary endpoint of the study was the absence of TPV dysfunction (reoperation, catheter reoperation, or hemodynamic dysfunction consisting of moderate or greater RA and / or mean RVOT gradient> 40 mm Hg). This was encountered by 54% of patients at 10 years.

“This compares quite favorably to experience with surgically implanted valves,” Jones said.

Older patients seem to do better, he said. Specifically, 65% of adults were free from TPV dysfunction at 10-year follow-up, compared to 47% of pediatric patients. This is because “they keep growing. So their somatic growth at some point exceeds the size of the valve they implanted, ”Jones said, adding that late endocarditis is also somewhat more common in children.

Overall, TPV-related endocarditis occurred in 19% of patients, representing an annualized event rate of 2% per patient-year. Major stent fractures increased only slightly between 5 and 10 years, from 15% to 16% of patients.

The Melody valve fulfills its design goal of extending the useful life of RVOT conduits and surgically implanted bioprosthetic valves and reducing the lifelong burden of repeat open heart operations, ”Jones concluded in his SCAI presentation.

Melody’s use has not been static – as therapy has matured over the decade, the need to introduce yourself has become better known, Jones told TCTMD. It has also become used in valve-in-valve interventions for tricuspid or mitral disease. And finally, he added, operators can use a hybrid surgical approach or, more rarely, surgical implantation to now allow even younger children to receive a Melody device.

Going forward, Medtronic is developing a next-generation balloon-expandable bioprosthetic TPV that will be available in larger sizes than Melody, which has an internal diameter of 20 or 22mm, he said.

“The big takeaways,” said Petit, “are that there’s a pretty decent reoperation rate at 10 years.” For patients under 22 years of age, 52% had not undergone reoperation; for patients 22 years of age or older, this rate was 74%. “And it’s not surprising,” he said, observing that stenosis and other issues can arise. Another key finding, Petit continued, is that the risk of endocarditis is not only “early, but constant.” And it is stable throughout these 10 years.

Harmony pivot test

John P. Cheatham, MD (Nationwide Children’s Hospital Heart Center, Phoenix, AZ), who presented the results of the pivotal Harmony trial, explained that among patients who initially undergo RVOT surgery, 75% do not receive a conduit. or bioprosthetic valve in time. These are the people who, as they develop PR over the years, are Harmony’s intended recipients. “It’s a larger population base that has this particular condition,” he said.

But what’s been difficult, Cheatham told TCTMD, is being able to design a TPV that can handle the anatomical variations between patients – resulting from the different RVOT surgeries they had at a young age and how they healed – as well as the dynamic shape and movement of the right ventricle. The first iteration of Harmony was implanted in a patient in 2009; since then, however, its design has evolved in order to meet these “engineering challenges,” Cheatham said.

In their pivotal trial, Cheatham et al include data on three Harmony generations: the initial 22mm valve used in an early feasibility study; a later 25mm version which is shorter in length, has larger diameters on its inlet and outlet ends, and is designed to treat a wider range of patients; and the most recent 25mm version which has been modified to make stakeout more predictable.

“Severe RP after surgical correction of RVOT abnormalities remains an important hemodynamic abnormality and a challenge to correct using transcatheter technologies,” Cheatham told viewers at SCAI.

Six-month data is available for 38 patients (of the original 40) given the first two Harmony models, and 1-month data is available for 10 who received the last model.

Of the total 50 patients (median age 28 years, 38% female), 92% were initially diagnosed with tetralogy of Fallot, 6% with pulmonary stenosis, and 2% with pulmonary atresia with intact ventricular septum. Pulmonary regurgitation was severe for 94% and moderate for 6%.

At 30 days, the primary safety endpoint for freedom from procedure or device-related mortality was 100%. Efficacy was defined as the absence of valve interventions plus an average RVOT gradient ≤ 40 mm Hg and a PR

The most common adverse events were ventricular tachycardia (18%), minor paravalvular leakage (10%), minor hemorrhage (10%), and premature ventricular beats (8%).

“We are very satisfied with the results so far. It certainly hit its safety rating and the effectiveness it needed to achieve, ”Cheatham told TCTMD. This Harmony data is currently being submitted to the United States Food and Drug Administration for pre-market approval, he said. A continuous access study on the 22 mm and more recent 25 mm versions is in progress.

Currently, the only two TPVs approved by the FDA are Melody and Sapien XT (Edwards Lifesciences).


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