Harmony TPV continues to show safety, efficacy for recipients at 1 year

In an expanded analysis presented at SCAI 2022, recipients of the Harmony transcatheter pulmonary valve (TPV) continued to demonstrate favourable clinical and haemodynamic outcomes, confirming previous results and showing continued device success across studies and valve types at 1 year and beyond.

“We knew that Harmony TPV patients were doing well acutely, but our data now validate these findings in the intermediate term,” said Dr Daniel Levi from the University of California, Los Angeles Mattel Children’s Hospital in Los Angeles, California, US, in a press release.

The analysis comprised participants from the Harmony Native Outflow Tract Early Feasibility Study (EFS; n=21), Harmony TPV Pivotal Trial (n=50), and Continued Access Study (CAS; n=37) who have completed ≥1 year follow-up. Of the 108 catheterized participants (mean age 29 years, 62 percent male), 106 had TPV implants, and 104 remained implanted for >24 hours. About 90 percent were originally diagnosed to have Tetralogy of Fallot. Almost all (96 percent) had severe pulmonary regurgitation (PR) by echo.

When stratifying the pooled cohort by valve type, 44 received TPV22 (n=21 [EFS], 21 [Pivotal], and 2 [CAS]), 45 had modified (m)TPV25 (n=10 [Pivotal] and 35 [CAS]), while 19 (all from Pivotal) received the discontinued clinical (c)TPV25 valve.

At 1 year, no deaths were reported, and 95 percent of TPV22 and 90 percent of mTPV25 recipients were free from PR, stenosis, and interventions. More than 85 percent of patients had none/trace PR by discharge, which increased to 92 percent by 1 year. Ninety-three percent of patients had none/trace paravalvular leak at 1 year. [SCAI 2022, abstract A-58]

No surgical repairs of the right ventricular outflow tract were reported. Four patients had explants (two each in the TPV22 and cTPV25 arms), four had intraprocedural manoeuvres (two wire repositionings and two balloon valve frames), and four had reinterventions (two each in the cTPV25 and mTPV25 arms) through 1 year.

Only one TPV recipient (in the TPV22 arm) had major stent fracture through 1 year. This implies that intervention to prevent permanent impairment or damage to a body structure was not required for almost all patients, said the researchers.

The rates of freedom from all-stent fracture through 1 year in the respective TPV22 and mTPV25 arms were 81 percent and 91 percent.

Ventricular tachycardia occurred in 18 percent of participants, more so in the mTPV25 vs the TPV22 arm (24 percent vs 7 percent). Nonetheless, none of the events were sustained.

Before the advent of TPV technology, congenital heart disease (CHD) was treated invasively (eg, open-heart surgery, surgical valve replacement). Harmony TPV provides a noninvasive, nonsurgical alternative for many CHD patients who are unable to receive TPVs.

“[Our pooled population] represents the largest cohort to date of Harmony TPV recipients … Even a year after implant, the valve is continuing to function well without significant interventions, obstruction, or regurgitation. This gives us confidence that we are going down the right treatment path with this pulmonary valve,” said Levi.

Levi and colleagues will continue to follow the patients through 10 years to further ascertain the long-term efficacy and safety of the Harmony TPV.