Transcatheter pulmonary valve replacement in pediatric patients

Risk of infective endocarditis after hybrid melody mitral valve replacement in infants: the French experience

OBJECTIVES

Surgical management of mitral valve disease is challenging in infants <1 year old. We aimed at reviewing the French experience with Melody mitral valve replacement in critically ill infants.

METHODS

A retrospective cohort study reporting the French experience with Melody mitral valve replacement.

RESULTS

Seven symptomatic infants [complete atrioventricular septal defect (n = 4, Down syndrome: n = 3), hammock valve (n = 3)] underwent Melody mitral valve replacement [age: 3 months (28 days to 8 months), weight: 4.3 kg (3.2-6.4 kg)] because of severe mitral valve regurgitation (6) or mixed valve disease (1) and 14 mm (11-16 mm) mitral valve annulus. In 2 patients whose valve was felt irreparable, Melody mitral valve replacement was performed straightaway. The others underwent 2 (1-3) previous attempts of valve repair; 3 were on extracorporeal membrane oxygenation. Melody mitral valve replacement led to competent valve and low gradient [3 mmHg, (1-4 mmHg)]. One patient died 3 days post-implant from extracorporeal membrane oxygenation-related stroke. Of the 6 discharged home patients, 3 (50%) were readmitted for a definite diagnosis (1) or high suspicion (2) of infective endocarditis, of which 2 died. Over the follow-up, 1 underwent balloon expansions of the valve at 9- and 16-months post-implant, and mechanical mitral valve replacement at 2 years; another is currently planned for transcatheter Melody valve dilation.

CONCLUSIONS

Melody mitral valve replacement may be considered in selected infants with small mitral valve annulus as an alternative to mechanical mitral valve replacement. Our experience highlights a high-risk of late infective endocarditis that deserves further consideration.

Computed Tomography-Derived Normative Values of Right Ventricular Outflow Tract Structures in the Pediatric Population

Recent advances in available percutaneous device technology require accurate measurements and quantification of relationships between right ventricular outflow tract (RVOT) structures in children with and without congenital heart disease to determine device suitability. To date, no population study has described normal reference ranges of these measurements by computed tomography (CT). We aimed to establish normative values for four CT-derived measurements between RVOT structures from a heterogeneous population without heart disease and develop z scores useful for clinical practice. Patients without heart disease who underwent cardiac CT between April 2014 and February 2021 at Children's Hospital Colorado were included. Distance between the right ventricular (RV) apex to pulmonary valve (PV), PV to pulmonary trunk bifurcation, and bifurcation to the right and left pulmonary artery was measured. Previously validated models were used to normalize the measurements and calculate Z scores. Each measurement was plotted against BSA and Z scores distributions were used as reference lines. Three-hundred and sixty-four healthy patients with a mean age of 8.8 years (range 1-21), 58% male, and BSA of 1 m2 (range 0.4-2.1) were analyzed. The Haycock formula was used to present data as predicted values for a given BSA and within equations relating each measurement to BSA. Predicted values and Z-score boundaries for all measurements are presented.We report CT-derived normative data for four measurements between RVOT structures from a heterogeneous cohort of healthy children. Knowledge of this normative data will be useful in both determining device fit and customizing future devices to accommodate the diverse pediatric size range.

[Modern possibilities for transcatheter pulmonary valve replacement]

The literature review is devoted to transcatheter pulmonary valve replacement. The authors summarize the indications, clinical data and current capabilities of transcatheter pulmonary valve replacement. The authors also overviewed modern valves for transcatheter pulmonary artery replacement. Effectiveness of transcatheter pulmonary valve implantation has been substantiated. Various studies comparing the outcomes of different valve systems for endovascular implantation were analyzed. The authors concluded the prospects for transcatheter pulmonary valve implantation.

Application of Speckle Tracking Echocardiography for Evaluating Ventricular Function after Transcatheter Pulmonary Valve Replacement

Pulmonary regurgitation usually leads to right heart dilatation and eventually right heart dysfunction, which is associated with a poor prognosis. Transcatheter pulmonary valve replacement is a developing treatment for pulmonary valve dysfunction that can take the place of traditional surgery and make up for the shortcomings of a large injury. Echocardiography plays a significant role in assessing ventricular function; however, conventional echocardiographic parameters have several limitations. Speckle tracking echocardiography has been regarded as a more accurate tool for quantifying cardiac function than conventional echocardiography. Therefore, the aim of this review was to summarize the application of speckle tracking echocardiography for evaluating right and left ventricular functions in patients after transcatheter pulmonary valve replacement.

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.

Early results of Pulsta® transcatheter heart valve in patients with enlarged right ventricular outflow tract and severe pulmonary regurgitation due to transannular patch

OBJECTIVE

The purpose of this study is to assess the feasibility, effectivity, and safety of a novel self-expandable valve system, Pulsta® transcatheter heart valve in patients with tetralogy of fallot and severe pulmonary regurgitation after transannular patch repair.

BACKGROUND

Severe pulmonary regurgitation after tetralogy of fallot repair is a life-threatening problem and should be treated by pulmonary valve implantation. Although percutaneous pulmonary valve implantation has been ever increasingly used for this purpose, available balloon-expandable valves have limitations and cannot be used by most patients. Pulsta® transcatheter heart valve is a new self-expandable valve system and offers a new solution to be used in patients with different types of native right ventricular outflow tract geometry.

PATIENTS AND METHODS

Ten patients with severe regurgitation after tetralogy of fallot repair with a transannular patch have been enrolled in the study according to echocardiographic examination. MRI was used in asymptomatic patients to delineate the indication and the right ventricular outflow tract geometry. Pulsta® transcatheter heart valve implantation was performed in ten patients, and preprocedural, procedure, and 6 months follow-up findings of the patients were evaluated.

RESULTS

Pulsta® pulmonary valve implantation was performed in ten patients successfully without any severe complications. Valve functions were perfect in six of ten patients, while the others had insignificant regurgitation by echocardiographic examination at the end of 6 months follow-up.

CONCLUSIONS

This study showed that Pulsta® transcatheter heart valve is a feasible, effective, and safe method in the treatment of severe pulmonary regurgitation due to transannular patch repair in patients with tetralogy of fallot.

Congenital heart disease: addressing the need for novel lower-risk percutaneous interventional strategies

INTRODUCTION

With the advent of improved neonatal care, increasingly vulnerable higher-risk patients with complex congenital heart anomalies are presenting for intervention. This group of patients will always have a higher risk of an adverse event during a procedure but by recognising this risk and with the introduction risk scoring systems and thus the development of novel lower risk procedures, the rate of adverse events can be reduced.

AREA COVERED

This article reviews risk scoring systems for congenital catheterization and demonstrates how they can be used to reduce the rate of adverse events. Then novel low risk strategies are discussed for low weight infants e.g. patent ductus arteriosus (PDA) stent insertion; premature infants e.g. PDA device closure; and transcatheter pulmonary valve replacement. Finally, how risk is assessed and managed within the inherent bias of an institution is discussed.

EXPERT OPINION

There has been a remarkable improvement in the rate of adverse events in congenital cardiac interventions but now, as the benchmark of mortality rate is switched to morbidity and quality of life, continued innovation into lower risk strategies and understanding inherent bias when assessing risk will be key to continuing this improvement.

Staged Percutaneous Management of Pulmonary Atresia and Intact Interventricular Septum: Stretching the Limits

Aims

Pulmonary atresia with intact ventricular septum (PA/IVS) can be treated by catheter-based interventions and complemented by various surgical procedures. We aim to determine a long-term treatment strategy to enable patients to be surgery free, depending solely on percutaneous interventions.

Methods and Results

We selected five patients from among a cohort of patients with PA/IVS treated at birth with radiofrequency perforation and dilatation of the pulmonary valve. Patients had reached a pulmonary valve annulus of 20 mm or larger on their biannual echocardiographic follow-up, with right ventricular dilatation. The findings, together with the right ventricular outflow tract and pulmonary arterial tree, were confirmed by multislice computerised tomography. Based on the angiographic size of the pulmonary valve annulus, all patients were successfully implanted with either Melody® or Edwards® pulmonary valves percutaneously, regardless of their small weights and ages. No complications were encountered.

Conclusion

We managed to stretch the age and weight limitations for performing percutaneous pulmonary valve implantation (PPVI): interventions were attempted whenever a pulmonary annulus size of >20 mm was reached, which was rationalised by the prevention of progressive right ventricular outflow tract dilatation and accommodating valves between 24 and 26 mm, which is enough to sustain a normal pulmonary flow in adulthood.

Tissue Engineered Transcatheter Pulmonary Valved Stent Implantation: Current State and Future Prospect

Patients with the complex congenital heart disease (CHD) are usually associated with right ventricular outflow tract dysfunction and typically require multiple surgical interventions during their lives to relieve the right ventricular outflow tract abnormality. Transcatheter pulmonary valve replacement was used as a non-surgical, less invasive alternative treatment for right ventricular outflow tract dysfunction and has been rapidly developing over the past years. Despite the current favorable results of transcatheter pulmonary valve replacement, many patients eligible for pulmonary valve replacement are still not candidates for transcatheter pulmonary valve replacement. Therefore, one of the significant future challenges is to expand transcatheter pulmonary valve replacement to a broader patient population. This review describes the limitations and problems of existing techniques and focuses on decellularized tissue engineering for pulmonary valve stenting.