Homografts and Xenografts for Right Ventricular Outflow Tract Reconstruction: Long-Term Results

One-Year Outcome of an Ongoing Pre-Clinical Growing Animal Model for a Tissue-Engineered Valved Pulmonary Conduit

Objectives: A self-constructed valved pulmonary conduit made out of a de-cellularized porcine small intestinal submucosal extracellular matrix biological scaffold was tested in a chronic growing lamb model. Methods: The conduit was implanted in pulmonary valve position in 19 lambs. We monitored clinical, laboratory, and echocardiographic findings until 12 months after surgery. In two animals, euthanasia was planned at nine and twelve months. Pre-mortem chest computed tomography and post-mortem pathologic work up were performed. Data are presented as frequency and percentage, median and range, or mean and standard deviation. Results: Twelve (63.2%) animals survived the perioperative period. Three unexpected deaths occurred during the follow-up period: one due to aspiration pneumonia at 23 days after surgery, and two due to early and late infective endocarditis of the conduit at 18 and 256 days. In the two animals with planned scarification, the pre-mortem CT scan revealed mild or no calcification within the conduit or valve leaflets. In the echocardiographic examination at 12 months, peak and mean systolic pressure gradients across the conduit valve were 6.5 (3-21) mmHg and 3 (2-12) mmHg, while valve regurgitation was none (n = 2), trivial (n = 5), moderate (n = 1), or severe (n = 1). No clinical or laboratory signs of hemolysis were seen. After 12 months of follow-up, the animals' body weights had increased from 33 (27-38) kg to 53 (38-66) kg (p = 0.010). Conclusions: Implantation of a valved pulmonary conduit in our growing lamb model was feasible. Infective endocarditis of the implanted valved conduit remained a significant complication.

[Redo right ventricular outflow tract repair for destruction of xenopericardial patch with monocusp]

Tetralogy of Fallot is the most common «blue type» heart defect. The goals of surgical correction are closure of ventricular septal defect and reconstruction of right ventricular outflow tract. The results of reconstructions depend on several factors: age, material, management and size of conduit. Some patients may require redo surgery due to dysfunction after primary correction.

The Utility of Invengenx® Bovine Patch for Right Ventricular Outflow Tract (RVOT) Reconstruction and Augmentation in the Surgical Management of Tetralogy of Fallot (TOF): A Contemporary Study and Review of the Literature

Background and objective Complex congenital heart diseases (CHDs), such as the tetralogy of Fallot (TOF), often warrant reconstruction and augmentation of the right ventricular outflow tract (RVOT). This procedure requires the use of both synthetic and natural materials. However, finding the ideal material for tissue implants can be challenging. Biological materials often face issues such as tissue degeneration, calcium deposition, antigenicity, rejection, shrinkage, and fibrosis. These issues can lead to complications such as stenosis and insufficiency, potentially requiring early reoperations. In light of this, this study aimed to investigate the effectiveness of the Invengenx® bovine patch for RVOT reconstruction and augmentation. Methods This was a retrospective observational study conducted among eight children who underwent TOF correction cardiac surgery. Their demographic and clinical characteristics, intraoperative findings, and postoperative follow-up results at six months were collected from the hospital patient database. Results There were no deaths or complications in this study. We observed a significant reduction in the gradient across the pulmonary valve and the outflow tract at six months post-procedure. The analysis demonstrated that the Invengenx® bovine patch was successful and did not lead to any complications. Conclusions This study demonstrates the safety and efficacy of this engineered bovine pericardial patch (Invengenx®) as a cardiovascular substitute for surgical repair of both simple and more complex congenital cardiac defects.

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.

Clinical outcomes of handmade polytetrafluoroethylene trileaflet-valved conduit used for pulmonary valve replacement

OBJECTIVES

To mitigate the shortage of homograft sources, the use of handmade trileaflet expanded polytetrafluoroethylene valves in pulmonary valve replacement has shown excellent results from multicentre studies conducted in Japan. However, world-wide data outside Japan are relatively insufficient. This study presents the long-term results of a single surgeon's use of flipped-back trileaflet method in a 10-year case series.

METHODS

We have developed an efficient way to make a trileaflet-valved conduit utilizing flipped-back method for pulmonary valve replacement and have employed the technique since 2011. Retrospective data were studied between October 2010 and January 2020. Echocardiography, electrocardiogram, Pro-Brain Natriuretic Peptide and Magnetic Resonance Imaging data were analysed.

RESULTS

Fifty-five patients were reviewed and median follow-up duration was 2.9 years. The majority of diagnoses was Tetralogy of Fallot (n = 41), and these patients subsequently underwent secondary pulmonary valve replacement at a median age of 15.6 years. Survival was 92.7% with the longest follow-up period being 10 years. There was no need for reoperation, and freedom from reintervention was 98.0% at 10 years. There were 4 deaths (3 in-hospital and 1 outpatient). One patient eventually received transcatheter pulmonary valve implantation. Postoperative echocardiography showed mild or less pulmonary stenosis and pulmonary regurgitation degree in 92.2% and 92.0% of patients, respectively. Comparable magnetic resonance imaging data (n = 25) showed significant reduction in right ventricular volumes but not in ejection fractions.

CONCLUSIONS

Our series showed satisfactory long-term function of handmade flipped-back trileaflet-valved conduit used in our patients. The simple design is efficiently reproducible without complex fabrication process.

Long-Term Follow-Up of Right Ventricle to Pulmonary Artery Biologic Valved Conduits Used in Pediatric Congenital Heart Surgery

Valved conduit reconstruction between the right ventricle (RV) and the pulmonary circulation is often necessary in the surgical treatment of complex congenital heart defects. The aim of this study is to evaluate the long-term performance of the three types of conduits we have used and assess risk factors for conduit failure. Retrospective, single-center review of 455 consecutive pediatric patients with 625 conduits from 1990 to 2019 undergoing RV-to-pulmonary artery (PA) reconstruction with a valved conduit. The three conduit types investigated were pulmonary homograft, aorta homograft, and bovine jugular vein (BJV) graft. Overall patient survival was 91.4%, freedom from conduit replacement (FCR) was 47.4%, and freedom from reintervention (FFR) was 37.8% with a median follow-up of 8.7 years (interquartile range 4.3-13.3 years). For pulmonary homografts, 10-, 20-, and 28-year FCR was 79.6%, 68.6%, and 66.0%, respectively. For aortic homografts, 10-, 20-, and 30-year FCR was 49.8%, 31.5%, and 23.0%, respectively. For BJV grafts, 10- and 19-year FCR was 68.1% and 46.0%, respectively. When controlling for baseline variables, FCR was similar for pulmonary homografts and BJV grafts. Overall patient survival was excellent. Risk factors for conduit failure in patients operated with reconstruction of the RV-PA outflow tract included low age, low weight, small conduit size, and certain cardiac diagnoses. There was no evidence for a shorter life span of the second graft. Pulmonary homografts and BJV grafts performed similarly but the risk of endocarditis was greater in the BJV group.

Outcomes after right ventricular outflow tract reconstruction with valve substitutes: A systematic review and meta-analysis

Introduction

This study aims to provide an overview of outcomes after right ventricular outflow tract (RVOT) reconstruction using different valve substitutes in different age groups for different indications.

Methods

The literature was systematically searched for articles published between January 2000 and June 2021 reporting on clinical and/or echocardiographic outcomes after RVOT reconstruction with valve substitutes. A random-effects meta-analysis was conducted for outcomes, and time-related outcomes were visualized by pooled Kaplan–Meier curves. Subgroup analyses were performed according to etiology, implanted valve substitute and patient age.

Results

Two hundred and seventeen articles were included, comprising 37,078 patients (age: 22.86 ± 11.29 years; 31.6% female) and 240,581 patient-years of follow-up. Aortic valve disease (Ross procedure, 46.6%) and Tetralogy of Fallot (TOF, 27.0%) were the two main underlying etiologies. Homograft and xenograft accounted for 83.7 and 32.6% of the overall valve substitutes, respectively. The early mortality, late mortality, reintervention and endocarditis rates were 3.36% (2.91–3.88), 0.72%/y (95% CI: 0.62–0.82), 2.62%/y (95% CI: 2.28–3.00), and 0.38%/y (95%CI: 0.31–0.47) for all patients. The early mortality for TOF and truncus arteriosus (TA) were 1.95% (1.31–2.90) and 10.67% (7.79–14.61). Pooled late mortality and reintervention rate were 0.59%/y (0.39–0.89), 1.41%/y (0.87–2.27), and 1.20%/y (0.74–1.94), 10.15%/y (7.42–13.90) for TOF and TA, respectively. Endocarditis rate was 0.21%/y (95% CI: 0.16–0.27) for a homograft substitute and 0.80%/y (95%CI: 0.60–1.09) for a xenograft substitute. Reintervention rate for infants, children and adults was 8.80%/y (95% CI: 6.49–11.95), 4.75%/y (95% CI: 3.67–6.14), and 0.72%/y (95% CI: 0.36–1.42), respectively.

Conclusion

This study shows RVOT reconstruction with valve substitutes can be performed with acceptable mortality and morbidity rates for most patients. Reinterventions after RVOT reconstruction with valve substitutes are inevitable for most patients in their life-time, emphasizing the necessity of life-long follow-up and multidisciplinary care. Follow-up protocols should be tailored to individual patients because patients with different etiologies, ages, and implanted valve substitutes have different rates of mortality and morbidity.

Systematic review registration

[www.crd.york.ac.uk/prospero], identifier [CRD42021271622].

Surgical pulmonary valve replacement at a tertiary adult congenital heart centre in the current era

Background

Surgical pulmonary valve replacement (PVR) is the standard cardiac operation in adult patients with congenital heart disease (ACHD). We report recent experience at a large tertiary centre and examine the impact of prosthesis type on outcomes.

Methods

All surgical PVRs performed at our tertiary centre between January 2003 and December 2018 were included.

Results

The study population included 490 patients (197 women; mean age 29.9 ± 13 years). The types of valves used were Homograft 179 (37%), Perimount 152 (31%), Mosaic 120 (24%), Hancock 31 (6%), and others 5 (1%). Seven (1.4%) early deaths occurred within 30 days after surgery. The survival rates at 1, 5, 10, and 15 years of follow-up were 98.3%, 97.7%, 96.8%, and 95.4%, respectively, whereas freedom from re-intervention was 99.8%, 96.6%, 90.2%, and 81.0%, respectively. During a mean follow-up of 6.5 ± 4.3 years, 27 (5.5%) patients required re-intervention. The type of valve used in these 27 patients during index operation showed no discernible difference in the probability of re-intervention; however, Mosaic valves required earlier re-intervention compared to Perimount valves.

Conclusion

Our data show no discernible difference in reoperation rates between the different types of prostheses used. On-going surveillance of patients after PVR and further research in developing a life-long prosthesis are clearly warranted.

Application of Homograft Valved Conduit in Cardiac Surgery

Valved conduits often correct the blood flow of congenital heart disease by connecting the right ventricle to the pulmonary artery (RV-PA). The homograft valved conduit was invented in the 1960s, but its wide application is limited due to the lack of effective sterilization and preservation methods. Modern cryopreservation prolongs the preservation time of homograft valved conduit, which makes it become the most important treatment at present, and is widely used in Ross and other operations. However, homograft valved conduit has limited biocompatibility and durability and lacks any additional growth capacity. Therefore, decellularized valved conduit has been proposed as an effective improved method, which can reduce immune response and calcification, and has potential growth ability. In addition, as a possible substitute, commercial xenograft valved conduit has certain advantages in clinical application, and tissue engineering artificial valved conduit needs to be further studied.

Right Ventricle to Pulmonary Artery Conduit Size Is Associated with Conduit and Pulmonary Artery Reinterventions After Truncus Arteriosus Repair

We studied conduit-related risk factors for mortality, conduit reintervention, conduit replacement, and pulmonary artery (PA) reinterventions after truncus repair. Patients who underwent truncus repair at our institution between 1995 and 2019 were studied. Cox proportional hazards modeling evaluated variables for association with mortality, time to conduit reintervention, time to conduit replacement, and time to PA reintervention. Truncus was repaired in 107 patients at median age of 17 days (IQR 9-45). Median follow-up time was 7 years. Aortic homografts were implanted in 57 (53%) patients, pulmonary homograft in 40 (37%), and bovine jugular conduit in 10 (9%). Median conduit size was 11 mm (IQR 10-12) and median conduit Z-score was 1.71 (IQR 1.08-2.34). At 5 years, there was 87% survival, 21% freedom from conduit reinterventions, 37% freedom from conduit replacements, and 55% freedom from PA reinterventions. Conduit size (HR 0.7, 95%CI 0.4-1.4, p=.41) and type (aortic homograft reference; bovine jugular vein graft HR 0.6, 95% CI 0.08-5.2, p=.69; pulmonary homograft HR 0.7, 95% CI 0.2-2.3, p=.58) were not associated with mortality. On multivariate analysis, the hazard for conduit reintervention, conduit replacement, and PA reintervention decreased with increasing conduit Z-score values of 1 to 2.5 (non-linear relationship, p<.01), with little additional reduction in hazard beyond this range. Implantation of a larger conduit within Z-score values of 1 and 2.5 is associated with a decreased hazard for conduit reintervention, conduit replacement, and PA reintervention after truncus repair. The type and size of the conduits did not impact mortality.

Outcomes Following Heterotopic Placement of Right Ventricle to Pulmonary Artery Conduits

BACKGROUND

We sought to evaluate the outcomes following right ventricle to pulmonary artery (RV-PA) conduit placement in pediatric patients, excluding those with a RV-PA conduit for the Ross procedure which is associated with improved conduit durability, partly related to its orthotopic position.

METHODS

Outcomes for 119 patients who underwent RV-PA conduit placement at a single institution from January 2004 to December 2016 were reviewed. Primary outcome measures were reintervention-free survival (RFS) and overall survival. Survival analyses were performed using the Kaplan-Meier method, and risk factors associated with reintervention were evaluated.

RESULTS

The median age at the time of conduit placement was 6 months (interquartile range, IQR: 1-14), and the median length of follow-up was 63 months (range: 0-156). During follow-up, 39 patients required conduit-related reintervention, while 6 patients died perioperatively with an overall survival of 90% at 10 years. Among the remaining 113 patients, the RFS at one, five, and ten years was 91% (84%-95%), 72% (60%-80%), and 33% (16%-50%), respectively. The median time to conduit replacement in the series was 43.5 months (IQR: 19.3-76.2). The use of a pulmonary homograft was associated with improved RFS (P = .03), and this was particularly pronounced in comparison with aortic homografts in neonates. Infection was the indication for replacement in only one patient.

CONCLUSIONS

The majority of the conduits placed during the neonatal period required conduit replacement before the age of five years. Endocarditis was not a common indication for replacement. In neonates and infants, we prefer pulmonary homografts for most indications.

Expanded Polytetrafluoroethylene Conduits With Bulging Sinuses and a Fan-Shaped Valve in Right Ventricular Outflow Tract Reconstruction

We developed a handmade expanded polytetrafluoroethylene (ePTFE) pulmonary valvular conduit (PVC) with bulging sinuses and a fan-shaped ePTFE valve for right ventricular outflow tract (RVOT) reconstruction. We aimed to investigate the results of this device in this multicenter study. From 2001 to 2020, 1776 patients underwent RVOT reconstruction using ePTFE PVCs at 65 institutions in Japan. The median age and body weight were 4.1 years (range, 3 days to 67.1 years) and 13.3 (range, 1.8-91.3) kg, respectively. The median PVC size was 18 (range, 8-24) mm. The median Z-value of the ePTFE PVC was 1.1 (range, -3.8 to 5.0). The ePTFE PVC conditions were investigated by cardiac echocardiography and catheterization. The median follow-up period was 3.3 years (range, 0 day to 16.2 years). There were only 9 cases (0.5%) with PVC-related unknown deaths. Reintervention was performed in 283 patients (15.9%), and 190 patients (10.7%) required explantation. Freedom from reintervention and explantation at 5/10 years were 86.7/61.5% and 93.0/69.1%, respectively. At the latest echocardiography, PVC regurgitation grade was better than mild in 88.4% patients. The average peak RVOT gradient was 15.7 ± 15.9 mm Hg at the latest cardiac catheterization. ePTFE PVC infection was detected in only 8 patients (0.5%). Relative stenosis due to somatic growth was the most common cause of PVC explantation. The performance of ePTFE in terms of durability, valvular performance, and the resistance against infection is considerable and may replace conventional prosthetic materials. Further improvement of the ePTFE membrane is essential to prevent valvular dysfunction.

Establishing a pre-clinical growing animal model to test a tissue engineered valved pulmonary conduit

Background

Many valvular pathologies of the heart may be only sufficiently treated by replacement of the valve if a reconstruction is not feasible. However, structural deterioration, thrombosis with thromboembolic events and infective endocarditis are commonly encountered complications over time and often demand a re-operation. In congenital heart disease the lack of small diameter valves with the potential to grow poses additional challenges and limits treatment options to homo- or xenograft implants.

Methods

In this study, a chronic sheep model (24 months follow-up), a self-constructed valved conduit was created out of a tissue engineered (TE) patch (CorMatrix® Cardiovascular, Inc, USA) and implanted in orthotopic right ventricular (RV)-pulmonary artery (PA) position. Thereafter, the sheep were regularly monitored by clinical, laboratory and echocardiographic examinations to evaluate cardiac function and the implanted RV-PA-conduit.

Discussion

Here, we summarize the study protocol and our experiences during the perioperative phase and the follow up period and explain how we constructed a valved conduit out of a commercially available TE patch.

Trial registration

License number: ZH 284/14.

Right Ventricular Outflow Tract Reconstruction in Infant Truncus Arteriosus: A 37-year Experience

BACKGROUND

Multiple conduits for right ventricular outflow tract reconstruction exist, although the ideal conduit that maximizes outcomes remains controversial. We evaluated long-term outcomes and compared conduits for right ventricular outflow tract reconstruction in children with truncus arteriosus.

METHODS

Records of patients who underwent truncus arteriosus repair at our institution between 1981 and 2018 were retrospectively reviewed. Primary outcomes included survival and freedom from catheter reintervention or reoperation. Secondary analyses evaluated the effect of comorbidity, operation era, conduit type, and conduit size.

RESULTS

One hundred patients met inclusion criteria. Median follow-up time was 15.6 years (interquartile range, 5.3-22.2). Actuarial survival at 30 days, 5 years, 10 years, and 15 years was 85%, 72%, 72%, and 68%, respectively. Early mortality was associated with concomitant interrupted aortic arch (hazard ratio, 5.4; 95% confidence interval, 1.7-17.4; P = .005). Median time to surgical reoperation was 4.6 years (interquartile range, 2.9-6.8; n = 58). Right ventricle to pulmonary artery continuity was established with an aortic homograft (n = 14), pulmonary homograft (n = 41), or bovine jugular vein conduit (n = 36) in most cases. Multivariate analysis revealed longer freedom from reoperation with the bovine jugular vein conduit compared with the aortic homograft (hazard ratio, 3.1; 95% confidence interval, 1.3-7.7; P = .02) with no difference compared with the pulmonary homograft. Larger conduit size was associated with longer freedom from reoperation (hazard ratio, 0.7; 95% confidence interval, 0.6-0.9; P < .001).

CONCLUSIONS

The bovine jugular vein conduit is a favorable conduit for right ventricular outflow tract reconstruction in patients with truncus arteriosus. Concomitant interrupted aortic arch is a risk factor for early mortality.

Influence of pregnancy on long-term durability of allografts in right ventricular outflow tract

BACKGROUND

There is very limited published evidence about the influence of pregnancy on allograft durability in right ventricular outflow tract position. We present the first study using mixed and joint modeling.

METHODS

This retrospective study compared clinical and valve related outcomes of all consecutive female hospital survivors in their fertile life phase (18-50 years) based on pregnancy. Serial echocardiographic measurements of pulmonary gradient and regurgitation were analyzed for their association with valve replacement using joint models for longitudinal and time-to-event data. Occurrence of first pregnancy was included as a time-dependent intermediate event in both the longitudinal and survival analyses of the joint model to assess its impact on the hemodynamic and clinical outcome.

RESULTS

In total, 196 consecutive women in their fertile life-phase with an allograft were included. Complete information of 176 (90%) allografts in 165 women was available, including 1395 echocardiograms. Of these women, 51 (30.9%) women had 84 completed pregnancies at an average age of 29.1 ± 3.9 (SD) years; 8.1 ± 6.1 years since allograft implantation. Tetralogy of Fallot was the most common diagnosis in both groups. After a mean follow-up of 15.2 years (range 0.1-30), 7 (13.7%) parous women underwent valve replacement versus 20 (17.5%) nulliparous women. During this follow-up, the mean allograft gradient in parous (24.2 mm Hg) and nulliparous (21.0 mm Hg) women was comparable (P = .225). A 1-mm Hg increase in pulmonary gradient increased the instantaneous risk of pulmonary valve replacement (PVR) by a ratio of 1.051 (P < .001), regardless of pregnancy. Similarly, development of moderate or severe regurgitation increased the risk of PVR (P = .038), regardless of pregnancy. Pregnancy was not associated with a change in the allograft gradient (P = .258), regurgitation grade (P = .774), or hazard of PVR (P = .796) during follow-up.

CONCLUSIONS

Pregnancy is not associated with impaired allograft durability in women with good cardiac health.

Outcomes of Prosthetic Valved Conduits for Right Ventricular Outflow Tract Reconstruction

There are limited data regarding the implantation of prosthetic valved conduits for right outflow tract reconstruction in pediatric patients in China. A retrospective review of 128 patients undergoing conduits implantation with a median follow-up of 33.3 months (range, 3.3 months to 10.1 years) was performed between 2009 and 2018. Multivariate Cox regression model was used to analyze the risk factors for mortality, reintervention and endocarditis. Freedom from reintervention and endocarditis were plotted using the Kaplan-Meier curve. Hospital mortality was 7.8%, and the late mortality was 3.1%. Patient survival at 1, 5 and 10 years was 92.2%, 87.1% and 84.3%, respectively. Freedom from reintervention at 1 and 5 years was 94.1% and 60.9%. Small size conduit (p = 0.019) and previous palliation (p < 0.001) were predictive of reintervention. Ten conduits developed endocarditis at a median of 4.8 years after implantation. Freedom from endocarditis at 1, 5 and 10 years was 99.1%, 93.0% and 58.0%, respectively. Diffuse stenosis of the conduit (p = 0.003) was an independent risk factor for late endocarditis. Both bovine jugular venous conduits and bovine pericardial prosthetic conduits are associated with acceptable outcomes. Reintervention remains high in patients who have smaller size conduit and undergo previous palliation. It is plausible that the suboptimal flow may be one of major mechanisms involved in the development of late endocarditis.

Contegra versus pulmonary homograft for right ventricular outflow tract reconstruction in newborns

OBJECTIVES

Pulmonary homografts are standard alternatives to right ventricular outflow tract reconstruction in congenital heart surgery. Unfortunately, shortage and conduit failure by early calcifications and shrinking are observed for small-sized homografts in younger patients. In neonates, Contegra® 12 mm (Medtronic Inc., Minneapolis, Minnesota, United States of America) could be a valuable alternative, but conflicting evidence exists. There is no published study considering only newborns with heterogeneous pathologies. We retrospectively compared the outcomes of these two conduits in this challenging population.

METHODS

Patients who underwent a right ventricular outflow tract reconstruction between January 1992 and December 2014 at the Hôpital Universitaire des Enfants Reine Fabiola were included. We retrospectively collected and analysed demographic, echocardiographic, surgical, and follow-up data.

RESULTS

Of the 53 newborns who benefited from a right ventricular outflow tract reconstruction during the considered period, 30 received a Contegra 12 mm (mean age 15 ± 8 days), and 23 a small (9-14 mm) pulmonary homograft (mean age 10 ± 7 days). Overall mortality was 16.6% with Contegra versus 17.4% in the pulmonary homograft group (p = 0.98 log-rank). Operative morbidity and early re-operation for conduit failure were not significantly different between the two groups. Mean follow-up in this study is 121 ± 74 months. Survival free from re-operation was not different between the two groups (p = 0.15). Multivariable analysis showed that weight and significant early gradient were factors associated with anticipated conduit failure.

CONCLUSIONS

Contegra 12 mm is a valid alternative to small pulmonary homografts in a newborn patient population.

TRIAL REGISTRATION

NCT03348397.

Contemporary Outcomes and Factors Associated With Mortality After a Fetal or Postnatal Diagnosis of Common Arterial Trunk

BACKGROUND

Common arterial trunk (CAT) is a rare anomaly with a spectrum of pathology. We sought to identify current trends and factors associated with postnatal outcomes.

METHODS

This was a single-centre review including 153 live births with planned surgery. Patients were analyzed as 2 cohorts based on era of CAT diagnosis (1990 to 1999 vs 2000 to 2014) and complexity of disease (simple vs complex). "Complex" required the association with significant aortic arch obstruction, truncal valve (TV) stenosis/regurgitation, and/or branch pulmonary artery (PA) hypoplasia, respectively.

RESULTS

Sixteen (10%) died preoperatively, and this outcome was associated with significant TV stenosis (odds ratio [OR] 4.55; P = 0.01) and regurgitation (OR 3.17; P = 0.04); 130 (95%) of 137 operated infants underwent primary complete repair. Their survival rates to 1 year improved from 54% to 85% after 2000, although this outcome remained substantially lower for cases with a complex vs simple CAT repair (76% vs 95%; OR 6.46; P = 0.006). Other risk factors associated with decreased 1-year survival included diagnosis before 2000 (OR 4.48; P = 0.038) and a lower birth weight (OR 8.0 per kg weight; P = 0.001). Finally, of 93 survivors beyond year 1 of life, 76 (82%) had undergone a total of 224 reinterventions. Only 15 (16%) were alive without any surgical or catheter-based reintervention at study end.

CONCLUSIONS

Despite recent surgical improvements, postnatal mortality continues to be substantial if CAT is complicated by significant pathology of the TV, aortic arch, or branch PAs. Reoperations and catheter interventions are eventualities for most patients during childhood.

Pulmonary valve replacement after right ventricular outflow tract reconstruction with homograft vs Contegra®: a case control comparison of mortality and morbidity

Background

Repair of congenital heart defects involving the right ventricular outflow tract may require the implantation of a right ventricle to pulmonary artery conduit. This conduit is likely to be replaced during childhood. This study compares the operative outcomes of the replacement procedure of Contegra® and homografts in pulmonary position.

Methods

From 1999 to 2016, 82 children underwent 87 right ventricle to pulmonary artery conduit replacements (60 Contegra® and 27 homografts). Demographics, operative and clinical data were obtained through a retrospective review of the medical records. The two groups were matched for comparison using propensity score matching. All the procedures were performed by the same team of surgeons.

Results

No statistically significant difference was observed between the two groups when considering the operative data for anesthesia, surgery, cardiopulmonary bypass and aortic clamping durations. A peroperative complication rate of 13.47% and 15.36% in Contegra® and homograft replacement groups respectively (p value = 0.758) was observed. There was no difference regarding the blood loss and fluid input. No statistically significant difference was observed between the two groups for the post-operative morbidity. We considered the Pediatric Risk of Mortality (PRISM) score, the day of extubation, the day of withdrawal of inotropic drugs, the length of the intensive care unit stay and the length of hospital stay. The overall mortality is 2.3% but there is no statistically significant difference between the two groups.

Conclusion

Right ventricle to pulmonary artery conduit replacement procedure can be achieved with a low surgical morbidity or mortality, not influenced by the type of conduit that is replaced. Therefore, the choice between homograft or Contegra® for right ventricle to pulmonary artery reconstruction should not be influenced by the future surgical risk during the replacement procedure.

Trial registration

NCT03048071. Registered 9 February 2017 (retrospectively registered).

Globular chitosan treatment of bovine jugular veins: evidence of anticalcification efficacy in the subcutaneous rat model

Vascular xenografts are widely used in cardiovascular surgery as an alternative to autologous vessels and vascular allografts. Calcification is one of the main drawbacks of vascular grafts, especially among young patients and children. Among different anticalcification approaches, chitosan emerges as a highly promising candidate due to its versatility, natural origin, and biocompatibility. We investigated the anticalcification efficacy of globular chitosan ("Chitozol") as it demonstrated the improved rate of water solubility as compared with conventional linear macromolecules of chitosan. In addition, we supposed that compact globular form of "Chitozol" molecules could provide effective penetration of extracellular matrix of bovine jugular veins (BJVs). Our results revealed that "Chitozol" treatment mitigated calcification in the experimental groups as compared to the control groups (without any treatment, conventional treatment with glutaraldehyde, and commercially available Contegra conduit). Different concentrations of "Chitozol" (0.3% and 3%), as well as different incubation times (15 and 30min), were equally effective in the prevention of calcification. In addition, "Chitozol" treatment with decellularization of BJVs demonstrated slightly improved stress-strain properties of unimplanted samples. Thus, the filling of fresh BJV with globular chitosan is proposed as a promising emerging treatment for the mitigation of calcific degeneration in BJVs xenografts.

Physical equivalency of wild type and galactose α 1,3 galactose free porcine pericardium; a new source material for bioprosthetic heart valves

Humans make high levels of antibody to carbohydrates with terminal galactose α 1,3 galactose (Gal) modifications. This Gal antigen is widely expressed in other mammals and is present on an array of current animal derived biomedical devices including bioprosthetic heart valves. There is growing interest in using Gal-free animal tissues from Gal knockout pigs (GTKO) as these tissues would not be affected by anti-Gal antibody mediated injury. In this study we compare the composition and biophysical characteristics of glutaraldehyde fixed porcine pericardium from standard and GTKO pigs. We show that with the exception of the Gal antigen which is only present in standard pig tissue both GTKO and standard pig tissue have the same general morphology and collagen content. Moreover uniaxial stress testing and suture retention testing indicate the tissues are equivalent in tensile strength. These studies indicate that genetic disruption of the α-galactosyltransferase (GGTA-1) which blocks synthesis of the Gal antigen has no significant impact on the structural integrity of porcine pericardium and suggest that this tissue could be directly substituted for standard pig pericardium in biomedical devices such as bioprosthetic heart valves.

STATEMENT OF SIGNIFICANCE

Surgical heart valve replacement is a proven life saving therapy to treat heart valve dysfunction due to birth defects, infection and the effects of aging. Bioprosthetic heart valves (BHV) made from glutaraldehyde fixed animal tissues are an effective durable therapy in older patients (>60years) but exhibit age-dependent structural valve degeneration (SVD) in younger patients (<60years). SVD is principally caused by BHV calcification. Immune injury contributes to age-dependent SVD through the interaction of galactose α 1,3 galactose (Gal) a dominant xenogeneic antigen present on commercial BHVs and universally abundant human anti-Gal antibody. This study measures the tissue equivalency between standard pig pericardium and Gal-free pericardium from genetically modified pigs as a first step towards making Gal-free BHVs.

Polymer-Based Reconstruction of the Inferior Vena Cava in Rat: Stem Cells or RGD Peptide?

As part of a program targeted at developing a resorbable valved tube for replacement of the right ventricular outflow tract, we compared three biopolymers (polyurethane [PU], polyhydroxyalkanoate (the poly(3-hydroxybutyrate-co-3-hydroxyvalerate-co-4-hydroxyvalerate) [PHBVV]), and polydioxanone [PDO]) and two biofunctionalization techniques (using adipose-derived stem cells [ADSCs] or the arginine-glycine-aspartate [RGD] peptide) in a rat model of partial inferior vena cava (IVC) replacement. Fifty-three Wistar rats first underwent partial replacement of the IVC with an acellular electrospun PDO, PU, or PHBVV patch, and 31 nude rats subsequently underwent the same procedure using a PDO patch biofunctionalized either by ADSC or RGD. Results were assessed both in vitro (proliferation and survival of ADSC seeded onto the different materials) and in vivo by magnetic resonance imaging (MRI), histology, immunohistochemistry [against markers of vascular cells (von Willebrand factor [vWF], smooth muscle actin [SMA]), and macrophages ([ED1 and ED2] immunostaining)], and enzyme-linked immunosorbent assay (ELISA; for the expression of various cytokines and inducible NO synthase). PDO showed the best in vitro properties. Six weeks after implantation, MRI did not detect significant luminal changes in any group. All biopolymers were evenly lined by vWF-positive cells, but only PDO and PHBVV showed a continuous layer of SMA-positive cells at 3 months. PU patches resulted in a marked granulomatous inflammatory reaction. The ADSC and RGD biofunctionalization yielded similar outcomes. These data confirm the good biocompatibility of PDO and support the concept that appropriately peptide-functionalized polymers may be successfully substituted for cell-loaded materials.

Current status of right ventricular outflow tract reconstruction: complete translation of a review article originally published in Kyobu Geka 2014;67:65-77

Right ventricular outflow tract (RVOT) reconstruction is becoming more prevalent as the number of adult patients who require repeated surgery long after definitive repair of congenital heart defects during childhood has increased. Early primary repair and annulus-preserving surgery have been the two current strategies of RVOT reconstruction from the viewpoint of timing and indications for surgical intervention; however, the long-term outcomes of both procedures remain unknown. Although various materials have been used for pulmonary valve replacement during RVOT reconstruction, deficient durability due primarily to immunological rejection frequently arises, particularly when implanted into young patients. A multicenter study in Japan showed that the clinical outcomes of expanded polytetrafluoroethylene (ePTFE) valved patches/conduits that we developed and manufactured comprised an excellent alternative material for RVOT reconstruction. Such enhanced outcomes might have partly been attributable to the biocompatibility and low antigenicity of ePTFE, and also to the fluid dynamic properties arising from the structural characteristics of a bulging sinus and a fan-shaped valve. However, numerous issues concerning RVOT reconstruction, such as indications for and the timing of definitive repair, as well as the choice of materials for pulmonary valve replacement, must be resolved to achieve better patient prognoses and quality of life. This review describes recent surgical strategies and outstanding issues associated with RVOT reconstruction.

An increased incidence of conduit endocarditis in patients receiving bovine jugular vein grafts compared to cryopreserved homograft for right ventricular outflow reconstruction

BACKGROUND

We compared the outcome of patients receiving bovine jugular vein grafts versus cryopreserved homografts for right ventricular outflow tract reconstruction.

METHODS

Between 2000 and 2012, 379 conduits (244 bovine jugular vein grafts, 135 homografts) were implanted in 298 patients (median age 50 months) with a median follow-up of 3.4 years.

RESULTS

Freedom from reoperation at 1, 5, and 7 years was 96.3%, 79.3%, and 64.2% after bovine jugular vein graft and 94.6%, 75.7%, and 68.6% after homograft insertion (p = 0.086). There were 24 cases of endocarditis, 23 associated with bovine jugular vein grafts (9.4%) and 1 associated with a homograft (0.7%; p < 0.001) at median follow-up of 44 months (range, 15 days to 10 years) after conduit implantation. After endocarditis, 15 of 24 conduits were replaced. Three patients had recurrent endocarditis in the revised conduit. Multivariate logistic regression analysis showed age less than 3 years and endocarditis to be significant risk factors associated with conduit replacement. Age more than 3 years and bovine jugular vein grafts were significant risk factors for graft endocarditis. Patients more than 3 years of age at bovine jugular vein graft implantation had significantly lower freedom from reoperation (p = 0.01).

CONCLUSIONS

Compared with homograft conduits, the use of bovine jugular vein grafts for right ventricular outflow tract reconstruction was associated with a significantly higher incidence of bacterial endocarditis and conduit deterioration in older children at our institution. That may influence decision making regarding conduit choice for right ventricular outflow tract reconstruction. Patients and practitioners should be aware of the late risks of bacterial endocarditis after bovine jugular vein graft implantation.

Homografts in aortic position: does blood group incompatibility have an impact on patient outcomes?

OBJECTIVES

Aortic homografts are an alternative to mechanical or biological valve prostheses. Homografts are generally not transplanted ABO-compatible while this policy is still under debate. The purpose of this study was to investigate whether ABO compatibility impacts on long-term outcomes or not.

METHODS

Between 1992 and 2009, 363 adult patients with a mean age of 52 years received homografts in aortic position. Donor and acceptor blood groups could be obtained for 335 patients. Sixty-three percent received blood group-compatible (n = 212) (Group iso) and 37% non-blood group-compatible allografts (n = 123) (Group non-iso).

RESULTS

The overall event-free survival (freedom from death or reoperation) was 55.5% (n = 186). In the iso group, the event-free survival was 84.1% at 5 years and 63.3% at 10 years. In the non-iso group, the event-free survival was 79.4% at 5 years and 51.8% at 10 years. 28.5% of patients (n = 35) with ABO-incompatible and 25.5% (n = 54) with ABO-compatible grafts required reoperation. The mean time to reoperation in the iso group was 97.3 vs 90 months in the non-iso group.

CONCLUSIONS

In 17 years of research, we have not yet found a statistical significant difference in blood group incompatibility regarding overall event-free survival. In our opinion, there is no need to use ABO-compatible homografts for aortic valve replacement in adults. Histological and immunohistochemical assays are mandatory to confirm our results.

Safe surgical strategy for extracardiac conduit replacement in common arterial trunk

Repair of common arterial trunk using an extracardiac right ventricular to pulmonary arterial conduit is the preferred method in most cardiac surgical centres. Reoperation is a fact of life for survivors of common arterial trunk and related cardiac lesions who have undergone such repairs. Long-term survivors may require periodic conduit revisions, with a potentially escalating technical difficulty and risk. Herein we present an analysis of the currently available choices for extracardiac conduits, and outline what we consider to be a safe and reliable surgical strategy for conduit revision.

Tetralogy of Fallot

Tetralogy of Fallot is the most common form of cyanotic congenital heart disease. In this condition, episodic worsening of hypoxemia results from dynamic shifts in physiology, so-called “Tet spells.” The relative frequency of this lesion and the risks of exacerbating “Tet spells” make anesthetic management of this patient population challenging. The conduct of palliative and reparative cardiac surgery is determined in large part by the anatomic variations within the spectrum of this disorder, most notably the severity of right ventricular outflow tract obstruction. This review will address the impact that the anatomic substrate has on the perioperative management of this interesting patient population.