Long-Term Outcomes After Melody Transcatheter Pulmonary Valve Replacement in the US Investigational Device Exemption Trial

Abstract

Background: The Melody valve was developed to extend the useful life of previously implanted right ventricular outflow tract (RVOT) conduits or bioprosthetic pulmonary valves, while preserving RV function and reducing the lifetime burden of surgery for patients with complex congenital heart disease.

Methods: Enrollment for the US Investigational Device Exemption study of the Melody valve began in 2007. Extended follow-up was completed in 2020. The primary outcome was freedom from transcatheter pulmonary valve (TPV) dysfunction (freedom from reoperation, reintervention, moderate or severe pulmonary regurgitation, and/or mean RVOT gradient >40 mm Hg). Secondary end points included stent fracture, catheter reintervention, surgical conduit replacement, and death.

Results: One hundred seventy-one subjects with RVOT conduit or bioprosthetic pulmonary valve dysfunction were enrolled. One hundred fifty underwent Melody TPV replacement. Median age was 19 years (Q1-Q3: 15-26). Median discharge mean RVOT Doppler gradient was 17 mm Hg (Q1-Q3: 12-22). The 149 patients implanted >24 hours were followed for a median of 8.4 years (Q1-Q3: 5.4-10.1). At 10 years, estimated freedom from mortality was 90%, from reoperation 79%, and from any reintervention 60%. Ten-year freedom from TPV dysfunction was 53% and was significantly shorter in children than in adults. Estimated freedom from TPV-related endocarditis was 81% at 10 years (95% CI, 69%-89%), with an annualized rate of 2.0% per patient-year.

Conclusions: Ten-year outcomes from the Melody Investigational Device Exemption trial affirm the benefits of Melody TPV replacement in the lifetime management of patients with RVOT conduits and bioprosthetic pulmonary valves by providing sustained symptomatic and hemodynamic improvement in the majority of patients. Registration: URL: https://www.clinicaltrials.gov; Unique identifier: NCT00740870.

Keywords: endocarditis; heart diseases; humans; mortality; pulmonary valve.

Figure 1.

Patient flow. Depicts patient status following discharge, showing the numbers of patients who underwent transcatheter pulmonary valve (TPV) dilation, TPV-in-TPV, or explant.

Figure 2.

Survival and transcatheter pulmonary valve (TPV) dysfunction. Kaplan-Meier curves depict (A) estimated freedom from all-cause death by age (≤21 vs >21 y), and freedom from TPV dysfunction, (B) overall, and (C) by age (≤21 vs >21 y). Estimates displayed with (95% CI). End point evaluated in patients implanted >24 h.

Figure 3.

Competing outcomes of reintervention, explant, and death. Competing outcome curves show the cumulative incidences of (A) reintervention and death or (B) explant and death. Estimated cumulative incidences for each outcome and Kaplan-Meier estimates at 10 y are indicated. End point evaluated in patients implanted >24 h.

Figure 4.

Echocardiographic and New York Heart Association (NYHA) functional class. In A, Mean right ventricular outflow tract (RVOT) gradients before and after implant and at annual study visits are depicted by box plots. Center line represents the median, and the marker the mean; the limits of the box are the 25th and 75th percentiles, and the whiskers indicate minimum–maximum. B, Pulmonary regurgitation severity before and after implant and at each annual follow-up visit. Percentages are rounded to the nearest whole number. For RVOT gradient and pulmonary regurgitation data, end points are assessed in patients implanted >24 h. Data were collected until patients received surgical or catheter-based reintervention, which rendered the original Melody valve nonfunctional. C, NYHA classification over time. Data represent outcomes in the group of patients with follow-up evaluation performed at each study visit.