Feasibility and Short-Term Outcomes of Percutaneous Transcatheter Pulmonary Valve Replacement in Small (<30 kg) Children With Dysfunctional Right Ventricular Outflow Tract Conduits

Prestenting for prevention of melody valve stent fractures: A systematic review and meta-analysis

INTRODUCTION

The role of right ventricular outflow tract (RVOT) prestenting in the prevention of Melody valve stent fractures (SFs) is not well defined. We aimed to perform a systematic review and meta-analysis comparing the incidence of SF in Melody valve transcatheter pulmonary implants with and without prestenting.

METHODS

PubMed, EMBASE, and Cochrane Central were searched for studies that reported the incidence of SF in Melody valve transcatheter pulmonary implants stratified by the presence or absence of RVOT prestenting. Subgroup analyses were performed for (1) SF associated with a loss of stent integrity and (2) SF requiring reintervention.

RESULTS

Five studies and 360 patients were included, of whom 207 (57.5%) received prestenting. Follow-up ranged from 15 to 30 months. SF were significantly reduced in the prestenting group (16.7%) when compared to no prestenting (33.5%) (odds-ratio [OR] 0.39; 95%CI 0.22-0.69). Patients who received prestenting also had a lower incidence of (1) SF associated with loss of stent integrity (OR 0.16; 95%CI 0.05-0.48) and (2) SF requiring reintervention (OR 0.15; 95%CI 0.02-0.91).

CONCLUSION

Our findings suggest that stenting of the RVOT prior to Melody valve implantation is associated with a reduction in the incidence of SF and fracture-related reinterventions.

Clinical and hemodynamic outcomes up to 7 years after transcatheter pulmonary valve replacement in the US melody valve investigational device exemption trial

BACKGROUND

Studies of transcatheter pulmonary valve (TPV) replacement with the Melody valve have demonstrated good short-term outcomes, but there are no published long-term follow-up data.

METHODS AND RESULTS

The US Investigational Device Exemption trial prospectively enrolled 171 pediatric and adult patients (median age, 19 years) with right ventricular outflow tract conduit obstruction or regurgitation. The 148 patients who received and were discharged with a TPV were followed up annually according to a standardized protocol. During a median follow-up of 4.5 years (range, 0.4-7 years), 32 patients underwent right ventricular outflow tract reintervention for obstruction (n=27, with stent fracture in 22), endocarditis (n=3, 2 with stenosis and 1 with pulmonary regurgitation), or right ventricular dysfunction (n=2). Eleven patients had the TPV explanted as an initial or second reintervention. Five-year freedom from reintervention and explantation was 76±4% and 92±3%, respectively. A conduit prestent and lower discharge right ventricular outflow tract gradient were associated with longer freedom from reintervention. In the 113 patients who were alive and reintervention free, the follow-up gradient (median, 4.5 years after implantation) was unchanged from early post-TPV replacement, and all but 1 patient had mild or less pulmonary regurgitation. Almost all patients were in New York Heart Association class I or II. More severely impaired baseline spirometry was associated with a lower likelihood of improvement in exercise function after TPV replacement.

CONCLUSIONS

TPV replacement with the Melody valve provided good hemodynamic and clinical outcomes up to 7 years after implantation. Primary valve failure was rare. The main cause of TPV dysfunction was stenosis related to stent fracture, which was uncommon once prestenting became more widely adopted.

CLINICAL TRIAL REGISTRATION

URL: http://www.clinicaltrials.gov. Unique identifier: NCT00740870.

Transcatheter pulmonary valve insertion, expanded use (beyond large conduits from the right ventricle to pulmonary artery), and future directions

Transcatheter pulmonary valve insertion is the most important advance in congenital interventional cardiology since atrial septal defect devices became commonly available 15 years ago. It has changed the way we look at a number of diverse diagnoses and changes how we plan, diagnose, operate, and follow-up patients. It has changed how we counsel families expecting a child that may benefit from it. Expanded use of the Melody® valve, outside its United States Food and Drug Administration approved indications, has helped numerous additional patients. The use of transcatheter pulmonary valve insertion in selected patients following surgical Gore-tex® bileaflet in valve right ventricular outflow tract reconstruction and those with a history of prior small homograft conduits will be discussed.

The future of transcatheter pulmonary valvulation

Percutaneous pulmonary valve implantation now has a key role in the setting of dysfunctional right ventricle-to-pulmonary artery conduits or failing bioprosthetic pulmonary valves. However, despite the excellent results obtained with the two devices available currently (the Melody(®) valve [Medtronic Inc., Minneapolis, MN, USA] and the Edwards SAPIEN(®) valve [Edwards Lifesciences, Irvine, CA, USA]), many patients eligible for pulmonary valve replacement remain unsuitable for percutaneous pulmonary valve implantation, mainly because of large native outflow tracts. Accordingly, one of the major challenges for the future is to expand percutaneous pulmonary valve implantation to a broader population of patients. Moving forward, there is important ongoing research that is intended to improve patient outcomes, expand percutaneous pulmonary valve implantation therapy and continue to reduce the number of open-heart surgeries in this population. In this review, we underline the limitations and issues associated with the devices available currently, and we focus on the development of new strategies (such as hybrid approaches or magnetic resonance-guided procedures), new devices (such as right ventricular outflow tract reducers or the novel Native Outflow Tract valved stent from Medtronic) and new technologies (such as tissue-engineered valves), which may help to take up these challenges and represent the future of transcatheter valve implantation.