A large multicenter real-world experience with the self-expanding Harmony valve for transcutaneous pulmonary valve replacement (TPVR) shows excellent clinical and hemodynamic outcomes through more than 1 year of follow-up. Nevertheless, the study shows, ventricular arrhythmia requiring intervention was common following implantation. Bryan H. Goldstein, MD of the University of Pittsburgh School of Medicine and Heart Institute, and colleagues reported these data in a manuscript published online Monday and in the April 9 issue of the Journal of the American College of Cardiology. In 2021, the U.S. Food and Drug Administration (FDA) approved the Harmony transcatheter pulmonary valve (TPV; Medtronic) for the treatment of severe pulmonary regurgitation in the native or surgically repaired right ventricular outflow tract (RVOT). In this system, a porcine pericardial tissue valve is stitched to a frame of self-expanding nitinol covered with polyester knit fabric. Two sizes are available: 22 mm (TPV22) and 25 mm (TPV25). Both valves are delivered using a single 25-French delivery system. Despite showing favorable results, the Native Outflow Tract Early Feasibility Study, Harmony TPV Pivotal Study, and the Continued Access Study were small and included only 87 patients in total. However, since this device became commercially available, more than 1,200 valve implants have been performed in the U.S. Thus, to test the device in a real-world population and outside the setting of prospective clinical trials, a multicenter longitudinal registry, hosted at UPMC Children’s Hospital of Pittsburgh, was created. In this initial registry report, the authors report acute procedural results and short-term hemodynamic and clinical outcomes following TPVR. This study included 243 consecutive patients with native RVOT pulmonic regurgitation (PR) who underwent TPVR through April 30, 2022, at 11 centers in the U.S. The mean cohort age was 31 years (interquartile range: 18-46 years), and the most common cardiac pathologies were tetralogy of Fallot (TOF) and pulmonary stenosis. Most of the patients had previously undergone surgery with transannular patching. Procedural success was achieved in all but one case (99.6% success rate), and serious adverse events occurred in 4.1% of patients. All patients except one had mild or less post-procedural PR, with 96% having none or trivial PR. No cases of procedural mortality, device embolism, or adverse effects of the device on the tricuspid valve, aortic root, or coronary arteries have been reported. However, ventricular arrhythmia necessitating treatment occurred in 19% of cases. In a multivariate analysis, a cardiac diagnosis of valvular PS or other was the only predictor significantly associated with post-procedural arrhythmia (in the univariate analysis, a supra-annular TPV implant was also borderline protective, suspected to be due to less contact between the valve nitinol frame and the RVOT). After a median follow-up of 13 months, 87% of patients had PR severity of none or trace, 10% had mild PR, and 2.3% had moderate PR. The presence of a paravalvular leak of more than trace was observed in 3% of patients (all with mild PVL), and the mean RVOT gradient was 10 mmHg. The primary composite outcome of a hemodynamic dysfunction (defined as PR greater than mild and RVOT mean gradient greater than 30 mmHg) and RVOT intervention was achieved in 99% of patients after 12 months and in 96% of patients after 24 months. Five patients died during the follow-up period (2.1%). Clinical manifestations of TPV frame perforation or erosion of the RVOT or branch pulmonary arteries were not observed in any of the patients. TPV thrombosis occurred in 8 patients (3.4%) over the follow-up period, with a median follow-up time of 4 months. Four of these patients were managed medically; one underwent balloon pulmonary valvuloplasty, and three underwent valve-in-valve TPVR. Endocarditis was diagnosed or suspected in six patients (2.6%) over the follow-up period at a median of 11 months. In their discussion, the authors emphasized the excellent technical success and safety of the device. They pointed out that, “in contrast to balloon expandable TPV prostheses, this self-expanding TPV appears to not put the coronary arteries or aortic root at significant risk for device-related compression.” In an accompanying editorial, Mary B. Taylor, MD, from the Children’s Hospital of Mississippi, University of Mississippi, Jackson, emphasized the unmet need for these valves. “Severe PR is the common progressive complication of TOF, one of the more common congenital heart lesions, often leading to debilitating right ventricular dysfunction.” She noted that a limitation in using the available balloon-expandable valves in these patients is their large and distending RVOT, which prevents secure placement of these valves. In her view, the new self-expanding valves have overcome many of these limitations. She then wrote, “Given the 80% to 98% 30-year survival of repaired tetralogy of Fallot, the demand for treatment of severe progressive pulmonary regurgitation is more important than ever.” Sources: Goldstein BH, McElhinney DB, Gillespie MJ, et al. Early Outcomes From a Multicenter Transcatheter Self-Expanding Pulmonary Valve Replacement Registry. J Am Coll Cardiol. 2024;83:1310–1321. Taylor MB. Real-World Experience With the Harmony Valve: Great Results for a Common Problem. J Am Coll Cardiol. 2024;83:1322–1323. Image Credit: Courtesy of Medtronic