The first series of implantations of the Harmony valve in Europe – the beginning of a new era for percutaneous pulmonary valve implantation?

Background: In patients with congenital heart disease (CHD) in whom the RVOT is too large and too compliant (native RVOT) for safe implantation of the available percutaneous valves, surgical treatment has remained the only possible treatment modality until recently. The evident necessity for inventing an alternative, percutaneous treatment option for patients with RVOT wider than 34 mm in diameter resulted in the developing of other self-expandable devices dedicated to the pulmonary position. One of these is the Harmony transcatheter pulmonary valve (Medtronic, Minneapolis, MN, USA), a porcine pericardial tissue valve attached to a self-expandible nitinol frame (Figure 1A).

Patients: In August 2024 four young adult patients with initial pulmonary stenosis (n=3) and Tetralogy of Fallot (n=1) with severe pulmonary valve regurgitation were scheduled for PPVI with Harmony valve implantation. All interventions were conducted through individual patient-based exception. All procedures were performed after obtaining the patients' informed consent and after receiving individual approval for special access to a nob CE-marked device by the German authorities (BfArM). The patient characteristics are shown in Table 1.

Implantation procedure: All procedures were performed using a biplane angiographic platform. Interventions were conducted under intravenous sedation in spontaneously breathing patients. The valve implantation was performed with the use of a 26 French long Gore DrySeal sheath (W. L. Gore & Associates, Flagstaff, Ariz, USA) from venous femoral access in 3 cases and from jugular venous access in one patient due to interruption of the inferior vena cava (IVC) with azygos vein continuation (Figure 1B-D). No vascular complications were recorded. All 4 implantations were successful, the patients showed good function of the newly implanted valve without a significant gradient or regurgitation. There were no adverse events during implantation and within 72 hours after the procedure. There was no increase in the frequency of arrhythmias, recorded in the early 72-hour Holter ECG compared to the pre-procedure Holter ECG in all patients. In transthoracic echocardiography at discharge, neither pulmonary regurgitation, paravalvular leak, nor stenosis were recorded. All patients receive oral Aspirin for 6 months post intervention.

Conclusions: Here we report the first-in-Europe series of patients after Harmony-valve implantation. The Harmony valve offers a feasible and safe treatment option for patients with severe pulmonary regurgitation and dilated RVOT after surgical transannular patch augmentation of the RVOT or balloon valvuloplasty in early childhood. The pending accessibility of this valve on the European market will offer an alternative, less invasive treatment option for many patients with variable RVOT anatomy, in whom the available balloon-expandable valves offer only limited applicability. Long-term follow-up will be required to determine the durability of this treatment option.