Ventricular Arrhythmias and Sudden Death Following Percutaneous Pulmonary Valve Implantation in Pediatric Patients

Outcomes of Bovine Jugular Vein Versus Porcine Valved Conduits for Right Ventricle to Pulmonary Artery Connection

Homografts conduits has been the gold standard for right ventricle to pulmonary artery (RV-PA) conduit. Several different types of xenograft valved conduits have been used as an alternative to homografts, due to their limited availability. In this single center, retrospective study, we analyzed the outcomes of patients with bovine jugular vein conduit (Contegra) and porcine valved conduit (Biointegral) in terms of survival and reintervention rate. Between 2012 and 2023, 44 children underwent surgical repair with RV-PA conduits using Contegra (n = 20) or Biointegral (n = 24). Patients with truncus arteriosus and patients who underwent unifocalization and Ross procedures were excluded. The operations in which other RV-PA conduits such as homografts, Gore-Tex grafts with PTFE handmade valved were used, were also excluded from the study. The median age of the patients was 19 (3-60) months and 84% of the patients (n = 37) had a history of previous intervention. Hospital mortality was 4.5% (n = 2). The median length of stay in intensive care unit and hospital was 5 (2-63) and 19 (2-145) days, respectively. 36 of the patients (82%) were followed for a median of 68 (4.8-143.7) months. There was one late death in Contegra group and five late deaths in Biointegral group. Survival analysis revealed that 1, 5, and 10-year survival rates were 100%, 90%, and 90% in Contegra group and 81%, 76.2%, and 33.9% (p = 0.047) in Biointegral group, respectively. During follow-up period, 11 patients (30.5%) needed reintervention (n = 3 in Contegra; n = 8 in Biointegral group). Freedom from reintervention rates were 100%, 94.1%, and 47.1% at 1, 5, and 10 years in Contegra group and 100% and 63.3% at 1 and 5 years in Biointegral group, respectively (p = 0.024). In this study, the outcomes of Contegra conduits were statistically significantly better than Biointegral conduits. Contegra is still the most valuable alternative to homografts. We believe that the choice of conduit in the first surgery is an important decision that directly affects survival and re-intervention rates.

Transcatheter Pulmonary Valve Implantation Using Self-Expandable Percutaneous Pulmonary Valve System: 3-Year CE Study Results

BACKGROUND

Pulmonary regurgitation is common during follow-up of patients after surgical repair of tetralogy of Fallot and other right ventricular outflow tracts (RVOTs). Many percutaneous pulmonary valves have been used but are limited to smaller RVOTs.

OBJECTIVES

Since August 2016, a multicenter CE (Conformité Européenne) study was initiated to evaluate a self-expandable VenusP-valve. We aimed to report the acute and 3-year follow-up results.

METHODS

A total of 81 patients with pulmonary regurgitation were recruited for VenusP-valve implantation and assessed for a 3-year period.

RESULTS

In all patients, VenusP-valves were successfully implanted. The mean age was 26.5 ± 13.3 years and the mean weight 59.5 ± 15.6 kg. There was no early procedure-related or late mortality. One patient experienced guidewire perforation of a branch pulmonary artery, causing hemoptysis, and 1 had ventricular tachycardia, at the end of the procedure. During follow-up, 1 patient developed runs of ventricular tachycardia and needed an implantable cardioverter-defibrillator and ablation of the RVOT 5 months after valve implantation. One developed endocarditis 11 months after implantation. After medical treatment, the valve has continued to function normally. One patient developed thrombus on the distal flare 3 years after implantation and was treated with anticoagulants. During 3-year follow-up, valve function has remained satisfactory and right ventricular remodeling has occurred in all patients.

CONCLUSIONS

We report the 3-year CE study results of percutaneous pulmonary valve implantation in patients with severe pulmonary regurgitation. The valve has shown promising safety and durability. Long-term evaluation is warranted.

Age-Related Ventricular Tachycardia Substrate Characteristics for Repaired Tetralogy of Fallot Before Transcatheter Pulmonary Valve Placement

BACKGROUND

Ventricular tachycardia (VT) substrate characteristics before transcatheter pulmonary valve replacement (TPVR) in repaired tetralogy of Fallot (rTOF) are unknown.

OBJECTIVES

In this study, the authors sought to evaluate substrates for sustained monomorphic VT before TPVR in rTOF.

METHODS

Retrospective (2017 to 2021) and prospective (commencing 2021) rTOF patients with native right ventricular outflow tract referred for electrophysiology study (EPS) before TPVR were included. Electrophysiologic findings and outcomes of VT ablation were determined.

RESULTS

A total of 180 patients (mean age 39 ± 14 years, 54% male, 71 retrospective, 109 prospective) were identified. At EPS, monomorphic VT was induced in 45 (25%), and a slowly conducting anatomic isthmus alone was observed in 40 (22%). VT isthmus conduction velocity decreased (-0.08 m/s per decade; P = 0.008) and VT inducibility (P < 0.001 for trend) and cycle length (CL) (+15 ms per decade, P = 0.005) increased with age. Multivariable factors associated with shorter VT CL included preserved isthmus conduction velocity (-50 ms per m/s; P = 0.02), absence of atrial flutter (-18 ms; P = 0.007), and improved RV ejection fraction (-16 ms per 10% increase; P = 0.007). Catheter ablation was acutely successful in 80/83 (96%). At repeated EPS after a median of 5 months, previously ablated substrates were evident in 3/24 (13%) and new VT substrates in 3/33 (9%).

CONCLUSIONS

Pre-TPVR VT substrates in rTOF demonstrate age-related degeneration that was associated with VT inducibility and VT CL. Both recovery of VT isthmus conduction and new VT substrates were observed after TPVR despite successful catheter ablation.

Ventricular Tachycardia Substrates in Children and Young Adults With Repaired Tetralogy of Fallot

BACKGROUND

Patients with repaired tetralogy of Fallot (rTOF) have a time-dependent increased risk of ventricular tachycardia (VT). Slow conducting anatomical isthmuses (SCAIs) are the dominant VT substrates in adults with rTOF. It is unknown if they are present at younger age.

OBJECTIVES

This study aimed to characterize VT substrates in patients with rTOF <30 years of age.

METHODS

Data of consecutive patients with rTOF aged <30 years who underwent electroanatomical mapping and programmed electrical stimulation between 2005 and 2022 were analyzed.

RESULTS

Fifty-five patients were included (median age: 15.8 years, IQR: 13.8-21.8 years; 15 repaired via ventriculotomy; 13 complex TOF variants). Twelve patients had right ventricle-to-pulmonary artery conduits inserted during initial repair or had early pulmonary valve replacement (PVR) (<1 year after repair). Indications for electroanatomical mapping and programmed electrical stimulation were spontaneous VT, before PVR, and risk stratification in 5, 40, and 10 patients, respectively. In 16 patients (29%), SCAI 3 was identified; no other SCAI was present. Monomorphic VT was inducible in 8 and related to SCAI 3 in 7 patients. Identified VT substrates were targeted by ablation. Right ventricle-to-pulmonary artery conduit/early PVR, ventriculotomy, and complex TOF were associated with SCAI 3 in univariable analysis. During a median follow-up of 5.3 years, VT recurred in 2 patients. No patients died.

CONCLUSIONS

In young patients with rTOF, SCAI 3 is the dominant substrate for VT. Complex TOF and interrelated type and timing of (re-)operation may contribute to the development of SCAI 3 already at a young age.

Ventricular arrhythmias following balloon-expandable transcatheter pulmonary valve replacement in the native right ventricular outflow tract

BACKGROUND

Ventricular arrhythmia incidence in children and adolescents undergoing transcatheter pulmonary valve replacement (TPVR) within the native right ventricular outflow tract (nRVOT) is unknown. We sought to describe the incidence, severity, and duration of ventricular arrhythmias and identify associated risk factors in this population.

METHODS

This was a retrospective cohort study of 78 patients <21 years of age who underwent TPVR within the nRVOT. Patients were excluded for pre-existing ventricular arrhythmia or antiarrhythmic use. Study variables included surgical history, valve replacement indication, valve type/size, and ventricular arrhythmia. Univariable logistic regression models were used to evaluate factors associated with ventricular arrhythmias, followed by subset analyses.

RESULTS

Nonsustained ventricular arrhythmia occurred in 26/78 patients (33.3%). The median age at the procedure was 10.3 years (interquartle range [IQR]: 6.5, 12.8). Compared with other nRVOT types, surgical repair with transannular patch was protective against ventricular arrhythmia incidence: odds ratio (OR): 0.35 (95% confidence interval [CI], 0.13-0.95). Patient weight, valve type/size, number of prestents, and degree of stent extension into the RVOT were not associated with ventricular arrhythmia occurrence. Beta blocker was started in 16/26 (61.5%) patients with ventricular arrhythmia. One additional patient was lost to follow-up. The median beta blocker duration was 46 days (IQR 42, 102). Beta blocker was discontinued in 10 patients by 8-week follow-up and in the remaining four by 9 months.

CONCLUSIONS

Though common after balloon-expandable TPVR within the nRVOT, ventricular arrhythmias were benign and transient. Antiarrhythmic medications were successfully discontinued in the majority at 6- to 8-week follow-up, and in all patients by 20 months.