Pulmonary Valve Replacement With a Trifecta Valve Is Associated With Reduced Transvalvular Gradient

Technical recommendations for computed tomography guidance of intervention in the right ventricular outflow tract: Native RVOT, conduits and bioprosthetic valves:: A white paper of the Society of Cardiovascular Computed Tomography (SCCT), Congenital Heart Surgeons' Society (CHSS), and Society for Cardiovascular Angiography & Interventions (SCAI)

This consensus document for the performance of Cardiovascular Computed Tomography (CCT) to guide intervention in the right ventricular outflow tract (RVOT) in patients with congenital disease (CHD) was developed collaboratively by pediatric and adult interventionalists, surgeons and cardiac imagers with expertise specific to this patient subset. The document summarizes definitions of RVOT dysfunction as assessed by multi-modality imaging techniques and reviews existing consensus statements and guideline documents pertaining to indications for intervention. In the context of this background information, recommendations for CCT scan acquisition and a standardized approach for reporting prior to surgical or transcatheter pulmonary valve replacement are proposed and presented. It is the first Imaging for Intervention collaboration for CHD patients and encompasses imaging and reporting recommendations prior to both surgical and percutaneous pulmonary valve replacement.

Technical Recommendations for Computed Tomography Guidance of Intervention in the Right Ventricular Outflow Tract: Native RVOT, Conduits, and Bioprosthetic Valves

This consensus document for the performance of cardiovascular computed tomography (CCT) to guide intervention in the right ventricular outflow tract (RVOT) in patients with congenital heart disease (CHD) was developed collaboratively by pediatric and adult interventionalists, surgeons, and cardiac imagers with expertise specific to this patient subset. The document summarizes definitions of RVOT dysfunction as assessed by multimodality imaging techniques and reviews existing consensus statements and guideline documents pertaining to indications for intervention. In the context of this background information, recommendations for CCT scan acquisition and a standardized approach for reporting prior to surgical or transcatheter pulmonary valve replacement are proposed and presented. It is the first Imaging for Intervention collaboration for CHD patients and encompasses imaging and reporting recommendations prior to both surgical and percutaneous pulmonary valve replacement.

Grafts and Patches: Optimized but Not Optimal Materials for Congenital Heart Surgery

A variety of materials are available for the surgery of children with congenital heart defects. In addition to growth-related mismatch, degeneration of the material in particular frequently leads to reoperation. Therefore, the choice of conduits and patches should be made carefully. This article provides an overview of the most commonly implanted materials in pediatric cardiac surgery.Structural changes can be detected in all available materials. Depending on the age at implantation and the site of implantation, the extent and time course of material degeneration vary. Autologous material is still the gold standard in reconstructive surgery. Biological materials have largely replaced artificial materials in clinical use.The search for the ideal material continues. In pediatric cardiac surgery, there are only optimized but no optimal materials.

Durability of Pulmonary Valve Replacement with Large Diameter Stented Porcine Bioprostheses

There is limited information about durability of large diameter porcine bioprostheses implanted for pulmonary valve replacement (PVR). We studied patients who underwent surgical PVR from 2002-2019 with a stented porcine bioprosthetic valve (BPV) with a labeled size ≥27 mm. The primary outcome was freedom from reintervention. During the study period, 203 patients underwent PVR using a porcine BPV ≥27 mm, 94% of whom received a Mosaic valve (Medtronic Inc., Minneapolis, MN). Twenty patients underwent reintervention from 3.4-12.0 years after PVR: 5 surgical and 15 transcatheter PVR procedures. The indication for reintervention was regurgitation in 13 patients, stenosis in 2, mixed disease in 4, and endocarditis in 1. Estimated freedom from reintervention was 97±1% at 5 years and 82±4% at 10 years, and freedom from prosthesis dysfunction (moderate or severe regurgitation and/or a maximum Doppler gradient ≥50 mm Hg) over time was 91±2% at 5 years and 74±4% at 10 years. Younger age and smaller true valve diameter were associated with shorter freedom from reintervention, but valve oversizing was not. The durability of large stented porcine bioprostheses in the pulmonary position is generally excellent, particularly in adolescents and adults, similar to various other types of BPV. In the current study, relative valve size was not associated with valve longevity, although the low event-rate in this population was a limiting factor.

Development of Tissue Engineered Heart Valves for Percutaneous Transcatheter Delivery in a Fetal Ovine Model

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A fully biodegradable fetal valve was developed using a zinc-aluminum alloy stent and electrospun PCL leaflets.

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In vitro evaluation of the valve was performed with accelerated degradation, mechanical, and flow loop testing, and the valve showed trivial stenosis and trivial regurgitation.

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A large animal model was used for percutaneous delivery of the valve to the fetal pulmonary annulus.

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Following implantation, the valve had no stenosis or regurgitation by echocardiography, and the fetal sheep matured and was delivered at term with the tissue-engineered valve.

This multidisciplinary work shows the feasibility of replacing the fetal pulmonary valve with a percutaneous, transcatheter, fully biodegradable tissue-engineered heart valve (TEHV), which was studied in vitro through accelerated degradation, mechanical, and hemodynamic testing and in vivo by implantation into a fetal lamb. The TEHV exhibited only trivial stenosis and regurgitation in vitro and no stenosis in vivo by echocardiogram. Following implantation, the fetus matured and was delivered at term. Replacing a stenotic fetal valve with a functional TEHV has the potential to interrupt the development of single-ventricle heart disease by restoring proper flow through the heart.

In-vitro and in-vivo evaluation of a novel bioprosthetic pulmonary valve for use in congenital heart surgery

Background

Management of congenital malformations of the pulmonary artery and valve can be challenging. The severity often demands early intervention, which is rarely definitive due to the natural growth and multiple surgeries may be required. An artificial valve made entirely from biodegradable materials that will serve as a bioscaffold for host recellularization would be an attractive solution for these patients. Such valves have been experimentally evaluated with various results. In this study, a simple valve design supported by an absorbable proximal stabilization ring is evaluated both in-vitro and in-vivo.

Methods

From a 6.7 × 5.0 cm sheet of CorMatrix® tissue we created the valve as an inverted tubegraft with three sutured commissures. A non-closed ring of LactoSorb® basally supported the valve. The commissure height was 2 cm. Inserted as an interposition graft the valve was tested in an in-vitro model and an acute porcine model. Right ventricular and pulmonary artery pressures were recorded.

Results

The in-vitro testing indicated a proper opening and closure function of valve at physiological simulated hemodynamic conditions. The in-vivo evaluation showed a peak right ventricular pressure of 38 mmHg and a peak pulmonary artery pressure of 27 mmHg and thereby a peak valve gradient of 11 mmHg. The pulmonary pressure wave demonstrated a dicrotic notch indicating competence of the valve.

Conclusion

This new pulmonary valve made entirely from biodegradable tissue worked in an acute setting and displayed a good hemodynamic profile. The valve gradient observed is equal to or superior of today’s surgical treatment options.

Pulmonary Valve Regurgitation: Neither Interventional Nor Surgery Fits All

Introduction: PV implantation is indicated for severe PV regurgitation after surgery for congenital heart defects, but debates accompany the following issues: timing of PV implantation; choice of the approach, percutaneous interventional vs. surgical PV implantation, and choice of the most suitable valve. Timing of pulmonary valve implantation: The presence of symptoms is class I evidence indication for PV implantation. In asymptomatic patients indication is agreed for any of the following criteria: PV regurgitation > 20%, indexed end-diastolic right ventricular volume > 120-150 ml/m2 BSA, and indexed end-systolic right ventricular volume > 80-90 ml/m2 BSA. Choice of the approach: percutaneous interventional vs. surgical: The choice of the approach depends upon the morphology and the size of the right ventricular outflow tract, the morphology and the size of the pulmonary arteries, the presence of residual intra-cardiac defects and the presence of extremely dilated right ventricle. Choice of the most suitable valve for surgical implantation: Biological valves are first choice in most of the reported studies. A relatively large size of the biological prosthesis presents the advantage of avoiding a right ventricular outflow tract obstruction, and also of allowing for future percutaneous valve-in-valve implantation. Alternatively, biological valved conduits can be implanted between the right ventricle and pulmonary artery, particularly when a reconstruction of the main pulmonary artery and/or its branches is required. Hybrid options: combination of interventional and surgical: Many progresses extended the implantation of a PV with combined hybrid interventional and surgical approaches. Major efforts have been made to overcome the current limits of percutaneous PV implantation, namely the excessive size of a dilated right ventricular outflow tract and the absence of a cylindrical geometry of the right ventricular outflow tract as a suitable landing for a percutaneous PV implantation. Conclusion: Despite tremendous progress obtained with modern technologies, and the endless fantasy of researchers trying to explore new forms of treatment, it is too early to say that either the interventional or the surgical approach to implant a PV can fit all patients with good long-term results.

Trifecta St. Jude medical® aortic valve in pulmonary position

Introduction: To evaluate an aortic pericardial valve for pulmonary valve (PV) regurgitation after repair of congenital heart defects.

Methods: From July 2012 to June 2016 71 patients, mean age 24 ± 13 years (four to years) underwent PV implantation of aortic pericardial valve, mean interval after previous repair = 21 ± 10 years (two to 47 years). Previous surgery at mean age 3.2 ± 7.2 years (one day to 49 years): tetralogy of Fallot repair in 83% (59/71), pulmonary valvotomy in 11% (8/71), relief of right ventricular outflow tract (RVOT) obstruction in 6% (4/71). Pre-operative echocardiography and MRI showed severe PV regurgitation in 97% (69/71), moderate in 3% (2/71) with associated RVOT obstruction. MRI and knowledge-based reconstruction 3D volumetry (KBR-3D-volumetry) showed mean PV regurgitation = 42 ± 9% (20–58%), mean indexed RV end-diastolic volume = 169 ± 33 (130–265) ml m^–2 BSA and mean ejection fraction (EF) = 46 ± 8% (33–61%). Cardio-pulmonary exercise showed mean peak O₂/uptake = 24 ± 8 ml kg^–1 min^–1 (14–45 ml kg^–1 min^–1), predicted max O₂/uptake 66 ± 17% (26–97%). Pre-operative NYHA class was I in 17% (12/71) patients, II in 70% (50/71) and III in 13% (9/71).

Results: Mean cardio-pulmonary bypass duration was 95 ± 30ʹ (38–190ʹ), mean aortic cross-clamp in 23% (16/71) 46 ± 31ʹ (8–95ʹ), with 77% (55/71) implantations without aortic cross-clamp. Size of implanted PV: 21 mm in seven patients, 23 mm in 33, 25 mm in 23, and 27 mm in eight. The z-score of the implanted PV was −0.16 ± 0.80 (−1.6 to 2.5), effective orifice area indexed (for BSA) of native PV was 1.5 ± 0.2 (1.2 to –2.1) vs. implanted PV 1.2 ± 0.3 (0.76 to –2.5) (p = ns). In 76% (54/71) patients surgical RV modelling was associated. Mean duration of mechanical ventilation was 6 ± 5 h (0–26 h), mean ICU stay 21 ± 11 h (12–64 h), mean hospital stay 6 ± 3 days (three to 19 days). In mean follow-up = 25 ± 14 months (six to 53 months) there were no early/late deaths, no need for cardiac intervention/re-operation, no valve-related complications, thrombosis or endocarditis. Last echocardiography showed absent PV regurgitation in 87.3% (62/71) patients, trivial/mild degree in 11.3% (8/71), moderate degree in 1.45% (1/71), mean max peak velocity through RVOT 1.6 ± 0.4 (1.0–2.4) m s^–1. Mean indexed RV end-diastolic volume at MRI/KBR-3D-volumetry was 96 ± 20 (63–151) ml m^–2 BSA, lower than pre-operatively (p < 0.001), and mean EF = 55 ± 4% (49–61%), higher than pre-operatively (p < 0.05). Almost all patients (99% = 70/71) remain in NYHA class I, 1.45% = 1/71 in class II.

Conclusion: (a) Aortic pericardial valve is implantable in PV position with an easy and reproducible surgical technique; (b) valve size adequate for patient BSA can be implanted with simultaneous RV remodelling; (c) medium-term outcomes are good with maintained PV function, RV dimensions significantly reduced and EF significantly improved; (d) adequate valve size will allow later percutaneous valve-in-valve implantation.

Evaluation of Infection Resistance of Biodegradable versus Conventional Annuloplasty Rings in an in vivo Rat Subcutaneous Model

Background: Biodegradable atrioventricular annuloplasty rings are theoretically more infection resistant due to their intra-annular implantation technique and nonporous structures (monofilament of poly-1,4-dioxanone). The aim of this study was to investigate the infection resistance of a biodegradable annuloplasty ring (Kalangos-Bioring®) in a rat subcutaneous implantation model and to compare it with a commonly used conventional annuloplasty ring (Edwards Physio II®). Methods: This study included 32 Wistar albino rats which were divided into 2 groups according to the implantation of sterile or infected annuloplasty rings as control and study groups. Each animal had 2 implantation pockets (made on the right and left side of the dorsal median line) where 1 cm of the biodegradable annuloplasty ring was implanted into one pocket and 1 cm of the conventional annuloplasty ring was implanted into the other pocket. The infection model was created by topical inoculation of 1 mL Staphylococcus aureus strain (2 × 107 colony-forming units/mL) into the implantation pockets before skin closure. Each group was equally divided into 4 subgroups according to different follow-up schedules. The animals were inspected for local as well as systemic infection signs, and the rings were explanted at weeks 2, 4, 9, and 14 following implantation. Implantation pockets were evaluated macroscopically as well as by histopathological examinations. Microbiological analysis of the explanted implants with surrounding tissue was done by using quantitative sonication method. Results: Conventional ring-implanted pockets showed a more prominent inflammation reaction than the biodegradable ring-implanted pockets, and this characteristic was found to be accentuated with bacterial contamination. The sterile rings did not reveal any positive cultures in either group. The number of positive cultures found in conventional rings contaminated with S. aureus was greater than in the biodegradable ring group (11/16 vs. 2/16 positive cultures, respectively; p = 0.0032). The amounts of growing bacteria in the culture environment were also statistically significantly higher in the conventional ring group (7,175 ± 5,936 vs. 181 ± 130 colony-forming units/mL, respectively; p < 0.0005). Conclusions: This is the first experimental study confirming the theoretical advantage of the infection resistance of the biodegradable annuloplasty ring (Kalangos-Bioring®) when implanted in an active infectious environment. Large animal models mimicking clinical scenarios and clinical comparative studies are needed to verify our results.