Balzer, David T.

BACKGROUND: Anatomic selection for Harmony valve implant is determined with the aid of a screening report and perimeter plot (PP) that depicts the perimeter-derived radius along the right ventricular outflow tract (RVOT) and projects device oversizing. The PP provides an estimation of suitability for implant, but its sensitivity as a screening method is unknown. This study was performed to describe anatomic features and outcomes in patients who underwent Harmony TPV25 implant despite a PP that predicted inadequate oversizing. METHODS: We reviewed RVOT anatomic features and measurements in patients who underwent transcatheter pulmonary valve replacement with the Harmony TPV25 device despite a PP that predicted inadequate oversizing. RESULTS: This study included 22 patients. There were no unsuccessful implants or adverse valve-related events. Anatomic features varied, but all patients fit into 1 of 3 anatomic types characterized by differences in RVOT dimensions. Type 1 patients (n=9) had a long RVOT with a choke point and a wide main pulmonary artery. Type 2 patients (n=6) had a short RVOT that was pyramidal in shape, with no choke point, and extensive main pulmonary artery lengthening/expansion during systole. Type 3 patients (n=7) had a short, bulbous main pulmonary artery with a choke point and an open pulmonary artery bifurcation. CONCLUSIONS: Transcatheter pulmonary valve replacement with the Harmony valve is feasible in some patients whose PP fit analysis predicts inadequate oversizing. All cases in this series fit into 1 of 3 anatomic patterns, which are not identified in the screening report. Implanters must review cases individually to assess the feasibility of the implant.

AbstractBackgroundThe Harmony TPV25 transcatheter pulmonary valve (Medtronic Inc.) is constructed with a self‐expanding stent frame comprising six zigged nitinol wires sewn together and covered with knitted polyester fabric, with flared inflow and outflow ends and a porcine pericardial valve sutured to the central portion of the device. It was approved for treatment of pulmonary regurgitation after prior right ventricular outflow tract repair in 2021. Early outcomes of this procedure have been excellent, but little is known about valve durability or ultimate mechanisms of dysfunction.MethodsWe collected data on patients who underwent reintervention for TPV25 dysfunction and described findings related to distortion of the stent frame and tissue accumulation.ResultsWe describe six patients who underwent valve‐in‐valve implant for TPV25 obstruction (peak catheterization gradient peak 28–73 mmHg) 10–28 months after implant. In all cases, there was tissue accumulation within the inflow and valve‐housing segments of the device and deformation of the self‐expanding valve frame characterized by variable circumferential narrowing at the junction between the valve housing and the inflow and outflow portions of the device, with additional geometric changes in all segments. All six patients underwent valve‐in‐valve implant that results in a final peak gradient ≤10 mmHg and no regurgitation.DiscussionThe occurrence of short‐term Harmony TPV25 dysfunction in multiple patients with a similar appearance of frame distortion and tissue accumulation within the inflow and valve housing portions of the device suggests that this may be an important failure mechanism for this valve. Potential causes of the observed findings are discussed. It is possible to treat this mechanism of TPV25 dysfunction with valve‐in‐valve implant using balloon expandable transcatheter valves.

AbstractObjectiveWe compared 5‐year outcomes of transcatheter pulmonary valve (TPV) replacement with the Melody TPV in the post‐approval study (PAS) and the investigational device exemption (IDE) trial.BackgroundAs a condition of approval of the Melody TPV after the IDE trial, the Food and Drug Administration required that a PAS be conducted to evaluate outcomes of TPV replacement in a “real‐world” environment. The 5‐year outcomes of the PAS have not been published, and the IDE and PAS trials have not been compared.MethodsThe cohorts comprised all patients catheterized and implanted at 5 IDE sites and 10 PAS sites. Differences in trial protocols were detailed. Time‐related outcomes and valve‐related adverse events were compared between the two trials with Kaplan–Meier curves and log‐rank testing.Results167 patients (median age, 19 years) were catheterized and 150 underwent TPV replacement in the IDE trial; 121 were catheterized (median age, 17 years) and 100 implanted in the PAS. Freedom from hemodynamic dysfunction (p = .61) or any reintervention (p = .74) over time did not differ between trials. Freedom from stent fracture (p = .003) and transcatheter reintervention (p = .010) were longer in PAS, whereas freedom from explant (p = .020) and TPV endocarditis (p = .007) were shorter. Clinically important adverse events (AEs) were reported in 14% of PAS and 7.2% of IDE patients (p = .056); the incidence of any particular event was low in both.ConclusionsHemodynamic and time‐related outcomes in the PAS and IDE trials were generally similar, confirming the effectiveness of the Melody TPV with real‐world providers. There were few significant complications and limited power to identify important differences in AEs. The lack of major differences in outcomes between the two studies questions the usefulness of mandated costly post‐approval studies as part of the regulatory process for Class III medical devices.