Initial experience with the self-expandable Venus P-ValveTM for percutaneous pulmonary valve replacement in large right ventricular outflow tracts - excellent early and mid-term outcomes

Objectives:  Percutaneous pulmonary valve implantation has become an integral element of the lifetime management of patients with right ventricular outflow tract lesions after repaired congenital heart disease. Balloon-expandable valves have shown very good short- and long-term results; however, their limitations in size exclude a substantial number of patients with unsuitably large dimensions from treatment. The self-expandable Venus P-Valve^TM is currently the only CE-marked valve specifically designed for percutaneous pulmonary valve implantation in patients with dilated right ventricular outflow tracts. Preliminary results are encouraging but experience is limited. We summarized our initial experience and and mid-term outcomes with the Venus P-Valve^TM.

Material and Methods: We performed a retrospective study including fifteen patients whom had undergone Venus P-Valve^TM implantation in our institution. Procedural data as well as clinical, imaging and hemodynamic data at baseline and last follow-up were recorded and analyzed.

Results: Mean patient age was 38.5±16.8 years, two patients were <18 years of age. The most frequent diagnosis was previous repair of Tetralogy of Fallot with a transannular patch. All valves were implanted in an annular position and deployed via the left pulmonary artery. Valve deployment was uneventful in all but one patient. A partial infolding of the distal aspect of the valve limited control of deployment and placement in that patient. Procedural success was 100%, there was no major valve-related procedural complication. At last follow-up (median 0.6 [range 0.1-6.6] years), valve function was excellent in all patients. Two patients had mild valvar regurgitation after 6.2 and 6.6 years, respectively, while all other patients had no or only trace regurgitation. There were no paravalvar leakages. Flow was unobstructed with a mean gradient estimated by echocardiography of 13±4 mmHg. NYHA functional class improved significantly (p=0.019) and right ventricular dimensions significantly decreased (right ventricular end-diastolic diameter 56±9mm vs. 48±7mm, p<0.001; right ventricular end-diastolic volume 157±33 vs. 117±25 ml/m², p=0.002). Transient benign ventricular arrhythmias were frequent. One patient experienced a severe arrhythmia with sustained ventricular tachycardia during follow-up. In addition to this patient, an implantable cardioverter-defibrillator was implanted in two patients due to recurring non-sustained ventricular tachycardias and symptomatic bradycardia with antiarrhythmic treatment.

Conclusions: Early and mid-term results with the Venus P-Valve^TM are excellent. It considerably extends the interventional options and offers a safe and effective alternative to surgery in patients with large right ventricular outflow tracts. Larger multi-institutional studies with longer follow-up duration are required to reliably assess the long-term performance and possible long-term complications of the Venus P-Valve^TM. Ventricular arrhythmias might be a cause of concern in this group of patients with already increased risk. Appropriate risk stratifications to guide arrhythmia screening and possible preemptive treatment by electrophysiological studies will have to be an objective for future studies.