Updates on transcatheter pulmonary valve replacement

Melody transcatheter pulmonary valve replacement: a single-center case series in Southeast Asia

BACKGROUND

Studies of transcatheter pulmonary valve replacement (TPVR) with the Melody valve have demonstrated good clinical and hemodynamic outcomes. Our study analyzes the midterm clinical and hemodynamic outcomes for patients who underwent Melody valve implantation in Southeast Asia.

METHODS

Patients with circumferential conduits or bioprosthetic valves and experiencing post-operative right ventricular outflow tract (RVOT) dysfunction were recruited for Melody TPVR.

RESULTS

Our cohort (n = 14) was evenly divided between pediatric and adult patients. The median age was 19 years (8-38 years), a male-to-female ratio of 6:1 with a median follow-up period of 48 months (16-79 months), and the smallest patient was an 8-year-old boy weighing 18 kg. All TPVR procedures were uneventful and successful with no immediate mortality or conduit rupture. The primary implant indication was combined stenosis and regurgitation. The average conduit diameter was 21 ± 2.3 mm. Concomitant pre-stenting was done in 71.4% of the patients without Melody valve stent fractures (MSFs). Implanted valve size included 22-mm (64.3%), 20-mm (14.3%), and 18-mm (21.4%). After TPVR, the mean gradient across the RVOT was significantly reduced from 41 mmHg (10-48 mmHg) to 16 mmHg (6-35 mmHg) at discharge, p < 0.01. Late follow-up infective endocarditis (IE) was diagnosed in 2 patients (14.3%). Overall freedom from IE was 86% at 79 months follow-up. Three patients (21.4%) developed progressive RVOT gradients.

CONCLUSION

For patients in Southeast Asia with RVOT dysfunction, Melody TPVR outcomes are similar to those reported for patients in the US in terms of hemodynamic and clinical improvements. A pre-stenting strategy was adopted and no MSFs were observed. Post-implantation residual stenosis and progressive stenosis of the RVOT require long term monitoring and reintervention. Lastly, IE remained a concern despite vigorous prevention and peri-procedural bacterial endocarditis prophylaxis.

Unmet Clinical Needs for Transcatheter Pulmonary Valves

A common feature of congenital heart disease is the presence of right ventricular outflow tract (RVOT) obstruction that can range from mild to severe and can lead to atresia of the pulmonary valve, in extreme conditions. RVOT abnormalities can frequently be corrected surgically or via interventional means. However, most of these patients will ultimately develop pulmonary valve insufficiency and eventual right ventricular dilation, which will require a pulmonary valve replacement at some point in their life to mitigate the detrimental effects of pulmonary valve regurgitation (PVR) on the right ventricle (RV). The evolution from the studies done by Philip Bonhoeffer to implant a pulmonary valve via transcatheter means, have provided a bedrock for transcatheter pulmonary valve replacement (TPVR). Yet, several areas of unmet need for a demographic of patients still exist. Here, we discuss the clinical unmet needs in children under 20 Kg and expand the use of hybrid and other TPVR approaches along with the current indications and contraindications for pulmonary valve replacement. The constraints and limitations from commercially available pulmonary valves will be discussed from a clinical standpoint. Finally, we explore the use of hybrid and periventricular delivery of transcatheter pulmonary valves in younger patients.

Echocardiographic Assessment of Melody Versus Sapien Valves Following Transcatheter Pulmonary Valve Replacement

OBJECTIVES

The aim of this study was to compare the immediate and midterm echocardiographic performance of the Melody (Medtronic Inc) and Sapien (Edwards Lifesciences Inc) valves after transcatheter pulmonary valve replacement (TPVR) in native and conduit right ventricular outflow tracts (RVOTs).

BACKGROUND

TPVR is now a common procedure, but limited data exist comparing postimplantation echocardiographic findings between Melody and Sapien valves.

METHODS

This was a single-institution retrospective cohort study of all patients who underwent successful TPVR from 2011 to 2020. Patient demographics, procedural details, and immediate and midterm echocardiographic findings were collected and compared between valve types using the Wilcoxon rank sum, chi-square, or Fisher exact test as appropriate. Subgroups were analyzed individually and were adjusted for multiple comparisons using the Bonferroni method.

RESULTS

A total of 328 patients underwent successful TPVR (Melody: n = 202, Sapien: n = 126). The groups had a similar baseline age, weight, and diagnosis. The most common indications for TPVR were pulmonary stenosis (32.2%) or mixed disease (46%) in the Melody group and pulmonary insufficiency in the Sapien group (52.4%) (P < 0.001). Sapien valves were more often placed in native RVOTs (43.7% vs 18.8%; P < 0.001). The discharge and follow-up mean and peak Doppler gradients were similar between the Melody and Sapien groups. Valves implanted in native RVOTs had significantly lower postimplantation gradients at each follow-up period.

CONCLUSIONS

Echocardiographic performance after TPVR was generally acceptable and similar when comparing Melody and Sapien valves despite differences in the indication and anatomy in each group. The peak and mean gradients were lower in transcatheter valves implanted in native RVOTs compared with those implanted in conduits or bioprosthetic valves.