Aortic valve replacement in neonates and infants: An analysis of the Society of Thoracic Surgeons Congenital Heart Surgery Database

Organizational challenges for partial heart transplantation

Partial heart transplantation (PHT) has emerged as a new treatment strategy to correct unrepairable heart valve dysfunction in pediatric patients. PHT selectively replaces the dysfunctional components of the recipient's heart and spares the native ventricles. As a result, the transplant biology of PHTs differs from heart transplants. Notably, donor hearts that are unsuitable for whole heart transplantation can be used, graft preservation can be prolonged and immunosuppression levels can be lowered. These nuances of PHT transplant biology have important implications for organizational aspects of PHT clinical application.

Immunogenicity of Homologous Heart Valves: Mechanisms and Future Considerations

Pediatric valvar heart disease continues to be a topic of interest due to the common and severe clinical manifestations. Problems with heart valve replacement, including lack of adaptive valve growth and accelerated structural valve degeneration, mandate morbid reoperations to serially replace valve implants. Homologous or homograft heart valves are a compelling option for valve replacement in the pediatric population but are susceptible to structural valve degeneration. The immunogenicity of homologous heart valves is not fully understood, and mechanisms explaining how implanted heart valves are attacked are unclear. It has been demonstrated that preservation methods determine homograft cell viability and there may be a direct correlation between increased cellular viability and a higher immune response. This consists of an early increase in human leukocyte antigen (HLA)-class I and II antibodies over days to months posthomograft implantation, followed by the sustained increase in HLA-class II antibodies for years after implantation. Cytotoxic T lymphocytes and T-helper lymphocytes specific to both HLA classes can infiltrate tissue almost immediately after implantation. Furthermore, increased HLA-class II mismatches result in an increased cell-mediated response and an accelerated rate of structural valve degeneration especially in younger patients. Further long-term clinical studies should be completed investigating the immunological mechanisms of heart valve rejection and their relation to structural valve degeneration as well as testing of immunosuppressant therapies to determine the needed immunosuppression for homologous heart valve implantation.

Long-term outcomes following the Ross procedure in neonates and infants: A multi-institutional analysis

OBJECTIVES

For neonates and infants with aortic valve pathology, the Ross procedure historically has been associated with high rates of morbidity and mortality. Data regarding long-term durability are lacking.

METHODS

The international, multi-institutional Ross Collaborative included 6 tertiary care centers. Infants who underwent a Ross operation between 1996 and 2016 (allowing a minimum 5 years of follow-up) were retrospectively identified. Serial echocardiograms were examined to study evolution in neoaortic size and function.

RESULTS

Primary diagnoses for the 133 patients (n = 30 neonates) included isolated aortic stenosis (14%, n = 19), Shone complex (14%, n = 19), and aortic stenosis plus other (excluding Shone complex; n = 95, 71%), including arch obstruction (n = 55), left ventricular hypoplasia (n = 9), and mitral disease (moderate or greater stenosis or regurgitation, n = 31). At the time of the Ross procedure, median age was 96 days (interquartile range, 36-186), and median weight was 4.4 kg (3.6-6.5). In-hospital mortality occurred in 13 of 133 patients (10%) (4/30 [13%] neonates). Postdischarge mortality occurred in 10 of 120 patients (8%) at a median of 298 days post-Ross. Post-Ross neoaortic dilatation occurred, peaking at 4 to 5 SDs above normal at 2 to 3 years before returning to near-baseline z-score at a median follow-up of 11.5 [6.4-17.4] years. Autograft/left ventricular outflow tract reintervention was required in 5 of 120 patients (4%) at a median of 10.3 [4.1-12.8] years. Freedom from moderate or greater neoaortic regurgitation was 86% at 15 years.

CONCLUSIONS

Neonates and infants experience excellent postdischarge survival and long-term freedom from autograft reintervention and aortic regurgitation after the Ross. Neoaortic dilatation normalizes in this population in the long-term. Increased consideration should be given to Ross in neonates and infants with aortic valve disease.

Why partial heart transplantation could be regulated as organ transplantation

Partial heart transplant (PHT) is a recent clinical innovation involving the transplantation of a segment of the heart (valves) directly from the deceased donor into the recipient patient. This procedure holds out the possibility of significant benefit, especially for pediatric patients because these grafts show growth potential after transplant, reducing or eliminating the current need for repeat procedures. The clinical process for donation and transplant of partial heart (PH) grafts generally follows an organ clinical pathway; however, the Food and Drug Administration has recently stated its intent to regulate PH as tissues, raising a host of regulatory considerations. PHT requires donor testing and eligibility determinations within a short, clinically viable timeframe and, similar to organ transplant, involves donor-recipient matching. Waitlist allocation policies that are a regulatory focus of the Organ Procurement and Transplantation Network including equity and efficiency may become relevant. Oversight of PHT by the Organ Procurement and Transplantation Network could be accomplished through interpretation of the vascular composite allograft definition or through designation by the US Department of Health and Human Services of PH grafts as organs. While some clinical questions remain unanswered, it is important to carefully address these regulatory considerations to support the emergence of this innovation and ensure the continued trust of the donating public and the patients who may benefit from PHT.

Association of left ventricular outflow tract size with arch morphology in interrupted aortic arch

OBJECTIVES

Left ventricular outflow tract obstruction (LVOTO) is a major cause of morbidity and mortality in infants with interrupted aortic arch (IAA). Left Ventricular Outflow Tract (LVOT) development may be flow-mediated, thus IAA morphology may influence LVOT diameter and subsequent reintervention. We investigated the association of IAA morphology [type and presence of aortic arch aberrancy (AAb)] with LVOT diameter and reintervention.

METHODS

All surgical patients with IAA (2001-2022) were reviewed at a single institution. We compared IAA-A versus IAA-B; IAA with aortic AAb versus none; IAA-B with aberrant subclavian (AAbS) artery versus others. Primary outcomes included LVOT diameter (mm), LVOTO at discharge (≥50 mmHg), and LVOT reintervention.

RESULTS

Seventy-seven infants (mean age 10 ± 19 days) were followed for 7.6 (5.5-9.7) years. Perioperative mortality was 3.9% (3/77) and long-term mortality was 5.2% (4/77). Out of 51 IAA-B (66%) and 22 IAA-A (31%) patients, 30% (n = 22) had AAb. Smaller LVOT diameter was associated with IAA-B [IAA-A: 5.40 (4.68-5.80), IAA-B: 4.60 (3.92-5.50), P = 0.007], AAb [AAb: 4.00 (3.70-5.04) versus none: 5.15 (4.30-5.68), P = 0.006], and combined IAA-B + AAbS [IAA-B + AAbS: 4.00 (3.70-5.02) versus other: 5.00 (4.30-5.68), P = 0.002]. The likelihood of LVOTO was higher among AAb [N = 6 (25%) vs N = 1 (2%), P = 0.004] and IAA-B + AAbS [N = 1 (2%) vs N = 6 (30%), P = 0.002]. Time-to-event analysis showed a signal towards increased LVOT reintervention in IAA-B + AAbS (P = 0.11).

CONCLUSIONS

IAA-B and AAb are associated with small LVOT diameter and early LVOTO, especially in combination. This may reflect lower flow in the proximal arch during development. Most reinterventions occur in IAA-B + AAbS, hence these patients should be carefully considered for LVOT intervention at the time of initial repair.

Animal models for partial heart transplantation

BACKGROUND

Partial heart transplantation delivers growing heart valve implants by transplanting the part of the heart containing the necessary heart valve only. In contrast to heart transplantation, partial heart transplantation spares the native ventricles. This has important implications for partial heart transplant biology, including the allowable ischemia time, optimal graft preservation, primary graft dysfunction, immune rejection, and optimal immunosuppression.

AIMS

Exploration of partial heart transplant biology will depend on suitable animal models. Here we review our experience with partial heart transplantation in rodents, piglets, and non-human primates.

MATERIALS & METHODS

This review is based on our experience with partial heart transplantation using over 100 rodents, over 50 piglets and one baboon.

RESULTS

Suitable animal models for partial heart transplantation include rodent heterotopic partial heart transplantation, piglet orthotopic partial heart transplantation, and non-human primate partial heart xenotransplantation.

DISCUSSION

Rodent models are relatively cheap and offer extensive availability of research tools. However, rodent open-heart surgery is technically not feasible. This limits rodents to heterotopic partial heart transplant models. Piglets are comparable in size to children. This allows for open-heart surgery using clinical grade equipment for orthoptic partial heart transplantation. Piglets also grow rapidly, which is useful for studying partial heart transplant growth. Finally, nonhuman primates are immunologically most closely related to humans. Therefore, nonhuman primates are most suitable for studying partial heart transplant immunobiology and xenotransplantation.

CONCLUSIONS

Animal research is a privilege that is contingent on utilitarian ethics and the 3R principles of replacement, reduction and refinement. This privilege allows the research community to seek fundamental knowledge about partial heart transplantation, and to apply this knowledge to enhance the health of children who require partial heart transplants.

Partial heart transplantation: Growing heart valve implants for children

Heart valves serve a vital hemodynamic function to ensure unidirectional blood flow. Additionally, native heart valves serve biological functions such as growth and self-repair. Heart valve implants mimic the hemodynamic function of native heart valves, but are unable to fulfill their biological functions. We developed partial heart transplantation to deliver heart valve implants that fulfill all functions of native heart valves. This is particularly advantageous for children, who require growing heart valve implants. This invited review outlines the past, present and future of partial heart transplantation.

Donor supply for partial heart transplantation in the United States

BACKGROUND

Congenital heart disease (CHD) is the most common cause of birth defects worldwide. Valvular defects are a common form of CHDs, and, at this time, treatment options for children with unrepairable valve disease are limited. Issues with anticoagulation, sizing, and lack of growth in valve replacement options can lead to high mortality rates and incidence of reoperations. Partial heart transplantation, or transplantation of fresh valve allografts, has recently been described as a strategy to provide a durable and non-thrombogenic alternative to conventional prostheses and provide growth potential in pediatric patients.

METHODS

The United Network for Organ Sharing (UNOS) database was queried to analyze the number of pediatric donor hearts that were not recovered but had viable valves (n = 3565) between January 2010 and September 2021. Recoverable valves were grouped by donor age: infants (age < 1 year), toddlers (age ≥1 and <3 years), and children (age ≥3 and <18 years). Demographic characteristics of donors were analyzed between age groups.

RESULTS

Infants, toddlers, and children had a total of 344, 465, and 2756 hearts with recoverable valves, respectively, over the study period, representing an average of 29, 39, and 230 hearts with recoverable valves per year.

CONCLUSION

The results of our study identify the minimum donor supply for partial heart transplantation. The actual number is likely higher because it includes hearts not entered in the UNOS database and domino transplants from orthotopic heart transplant recipients. Partial heart transplantation is logistically feasible as there are recoverable valves available for all age groups, fulfilling a clinical need in pediatric patients with unrepairable valve disease.

Morbidity and Mortality of Heterotopic Partial Heart Transplantation in Rodent Models

Unrepairable congenital heart valve disease is an unsolved problem in pediatric cardiac surgery because there are no growing heart valve implants. Partial heart transplantation is a new type of transplant that aims to solve this problem. In order to study the unique transplant biology of partial heart transplantation, animal models are necessary. This study aimed to assess the morbidity and mortality of heterotopic partial heart transplantation in rodent models. This study assessed two models. The first model involved transplanting heart valves from donor animals into the abdominal aortic position in the recipient animals. The second model involved transplanting heart valve leaflets into the renal subcapsular position of the recipient animals. A total of 33 animals underwent heterotopic partial heart transplantation in the abdominal aortic position. The results of this model found a 60.61% (n = 20/33) intraoperative mortality rate and a 39.39% (n = 13/33) perioperative mortality rate. Intraoperative mortality was due to vascular complications from the procedure, and perioperative mortality was due to graft thrombosis. A total of 33 animals underwent heterotopic partial heart transplantation in the renal subcapsular position. The results of this model found a 3.03% (n = 1/33) intraoperative mortality rate, and the remaining 96.97% survived (n = 32/33). We conclude that the renal subcapsular model has a lower mortality rate and is technically more accessible than the abdominal aortic model. While the heterotopic transplantation of valves into the abdominal aortic position had significant morbidity and mortality in the rodent model, the renal subcapsular model provided evidence for successful heterotopic transplantation.

Growing Heart Valve Implants for Children

The current standard of care for pediatric patients with unrepairable congenital valvular disease is a heart valve implant. However, current heart valve implants are unable to accommodate the somatic growth of the recipient, preventing long-term clinical success in these patients. Therefore, there is an urgent need for a growing heart valve implant for children. This article reviews recent studies investigating tissue-engineered heart valves and partial heart transplantation as potential growing heart valve implants in large animal and clinical translational research. In vitro and in situ designs of tissue engineered heart valves are discussed, as well as the barriers to clinical translation.

Partial heart transplantation for pediatric heart valve dysfunction: A clinical trial protocol

Congenital heart defects are the most common type of birth defects in humans and frequently involve heart valve dysfunction. The current treatment for unrepairable heart valves involves valve replacement with an implant, Ross pulmonary autotransplantation, or conventional orthotopic heart transplantation. Although these treatments are appropriate for older children and adults, they do not result in the same efficacy and durability in infants and young children for several reasons. Heart valve implants do not grow with the. Ross pulmonary autotransplants have a high mortality rate in neonates and are not feasible if the pulmonary valve is dysfunctional or absent. Furthermore, orthotopic heart transplants invariably fail from ventricular dysfunction over time. Therefore, the treatment of irreparable heart valves in infants and young children remains an unsolved problem. The objective of this single-arm, prospective study is to offer an alternative solution based on a new type of transplant, which we call "partial heart transplantation." Partial heart transplantation differs from conventional orthotopic heart transplantation because only the part of the heart containing the heart valve is transplanted. Similar to Ross pulmonary autotransplants and conventional orthotopic heart transplants, partial heart transplants contain live cells that should allow it to grow with the recipient child. Therefore, partial heart transplants will require immunosuppression. The risks from immunosuppression can be managed, as seen in conventional orthotopic heart transplant recipients. Stopping immunosuppression will simply turn the growing partial heart transplant into a non-growing homovital homograft. Once this homograft deteriorates, it can be replaced with a durable adult-sized mechanical implant. The protocol for our single-arm trial is described. The ClinicalTrials.gov trial registration number is NCT05372757.

Ross Procedure in Children: The Society of Thoracic Surgeons Congenital Heart Surgery Database Analysis

BACKGROUND

Single-center studies have demonstrated excellent results for the Ross procedure in children. We aimed to evaluate national variation in clinical outcomes using The Society of Thoracic Surgeons Congenital Heart Surgery Database.

METHODS

The database was used to identify 2805 children undergoing the Ross procedure from 2000 through 2018, comprising 163 neonates (<30 days, 5.8%), 448 infants (30-365 days, 16.0%), 1444 children (1-12 years, 51.5%), and 750 teenagers (13-17 years, 26.7%). Centers were divided into terciles by procedural volume. Multivariable logistic regression was used to identify predictors of a composite outcome of operative mortality, neurologic deficit, or renal failure requiring dialysis.

RESULTS

Neonates and infants were more likely to present with aortic stenosis than children and teenagers (61.7% [n = 377] vs 34.6% [n = 760]; P < .01) and have risk factors including preoperative shock (9.2% [n = 56] vs 0.4% [n = 8]; P < .01). Operative mortality was 24.1% (n = 39) in neonates, 11.2% (n = 50) in infants, 1.5% (n = 21) in children , and 0.8% (n = 6) in teenagers (P < .01). Independent predictors of the composite outcome in children aged <1 year included neonatal age (odds ratio [OR], 3.0; 95% CI, 1.9-4.8), low-volume center (OR, 2.1; 95% CI, 1.1-3.9), and procedure year (OR, 0.7; 95% CI, 0.5-0.9 per 5 years). In children aged ≥1 year, no association was found between center volume, procedure year, and outcome.

CONCLUSIONS

The Ross procedure is being performed with low mortality in children aged ≥1 year throughout North America. High-volume centers have improved outcomes in children aged <1 year, who have different anatomic characteristics and risk profiles.

Ross procedure in neonates and infants: A valuable operation with defined limits

OBJECTIVE

The Ross procedure is an important tool that offers autologous tissue repair for severe left ventricular outflow tract (LVOT) pathology. Previous reports show that risk of mortality is highest among neonates and infants. We analyzed our institutional experience within this patient cohort to identify factors that most affect clinical outcome.

METHODS

A retrospective chart review identified all Ross operations in neonates and infants at our institution over 27 years. The entire study population was analyzed to determine risk factors for mortality and define outcomes for survival and reintervention.

RESULTS

Fifty-eight patients underwent a Ross operation at a median age of 63 (range, 9-156) days. Eighteen (31%) were neonates. Eleven (19%) patients died before hospital discharge. Multiple regression analysis of the entire cohort identified young age (hazard ratio [HR], 1.037; P = .0045), Shone complex (HR, 17.637; P = .009), and interrupted aortic arch with ventricular septal defect (HR, 16.01; P = .031) as independent predictors of in-hospital mortality. Receiver operating characteristic analysis (area under the curve, 0.752) indicated age younger than 84 days to be the inflection point at which mortality risk increases. Of the 47 survivors, there were 2 late deaths with a mean follow-up of 6.7 (range, 2.1-13.1) years. Three patients (6%) required LVOT reintervention at 3, 8, and 17.5 years, respectively, and 26 (55%) underwent right ventricular outflow tract reintervention at a median of 6 (range, 2.5-10.3) years.

CONCLUSIONS

Ross procedure is effective in children less than one year of age with left sided obstructive disease isolated to the aortic valve and/or aortic arch. Patients less than 3 months of age with Shone or IAA/VSD are at higher risk for morbidity and mortality. Survivors experience excellent intermediate-term freedom from LVOT reintervention.

Ross Procedure in Neonate and Infant Populations: A Meta-Analysis Review

Objective

This study aims to perform a meta-analysis of early and late outcomes of the Ross/Ross-Konno procedures in neonates/infants.

Methods

A meta-analysis was performed in accordance with PRISMA guidelines. We used Ovid versions of MEDLINE/PubMed for relevant studies and included those that reported Ross/Ross-Konno operations in neonates/infants and at least one of the predetermined clinical outcomes. I2 and double arcsine methods assessed the heterogeneity between pooled estimates. We used a random-effect model to account for heterogeneity with MetaXL. We calculated point estimates of a pooled estimates along with its 95% CI.

Results

587 neonate/infant patients were included with median age of 87.5 days old. The follow-up range was five days to 23 years. Early mortality reported in 25 studies with pooled estimates of 18.3% (95% CI: 13.6%-23.5%). Estimates ranged from 0% to 50% with relatively substantial heterogeneity ( P = .01, I2 = 48.6%). Late mortality reported in 22 studies with pooled incidence of 9.7% (95% CI: 5.9%-14.3%). Estimates ranged from 0% to 53% with relatively substantial heterogeneity ( P = .01, I2 = 46.1%). Autograft reintervention reported in 18 studies with pooled estimate of 19.2% (95% CI: 7.3%-34.5%). Estimates ranged from 0% to 81.8% with high heterogeneity ( P < .001, I2 = 90.5%). Right ventricle-to-pulmonary artery conduit reintervention reported in 16 studies with pooled estimates of 32.0% (95% CI: 20.9%-44.12%). Estimates ranged from 0% to 92.3% with high heterogeneity ( P < .001, I2 = 75.9%).

Conclusions

The data suggest that the Ross/Ross-Konno procedure in neonates/infants still carries significant risk of early/late mortality and autograft/conduit reintervention. The high variability of results among centers confirms the need for surgical expertise and good patient selection. Prospective multicenter studies are warranted to investigate the rate of autograft reintervention and the impact on long-term survival in this specific population.

Surgical techniques for aortic valve xenotransplantation

Background

Heart valve replacement in neonates and infants is one of the remaining unsolved problems in cardiac surgery because conventional valve prostheses do not grow with the children. Similarly, heart valve replacement in children and young adults with contraindications to anticoagulation remains an unsolved problem because mechanical valves are thrombogenic and bioprosthetic valves are prone to early degeneration. Therefore, there is an urgent clinical need for growing heart valve replacements that are durable without the need for anticoagulation.

Methods

A human cadaver model was used to develop surgical techniques for aortic valve xenotransplantation.

Results

Aortic valve xenotransplantation is technically feasible. Subcoronary implantation of the valve avoids the need for a root replacement.

Conclusion

Aortic valve xenotransplantation is promising because the development of GTKO.hCD46.hTBM transgenic pigs has brought xenotransplantation within clinical reach.

Aortic valve replacement in pediatric patients: 30 years single center experience

Background

The choice of aortic valve replacement needs to be decided in an interdisciplinary approach and together with the patients and their families regarding the need for re-operation and risks accompanying anticoagulation. We report long-term outcomes after different AVR options.

Methods

A chart review of patients aged < 18 years at time of surgery, who had undergone AVR from May 1985 until April 2020 was conducted. Contraindications for Ross procedure, which is performed since 1991 at the center were reviewed in the observed non-Ross AVR cohort. The study endpoints were compared between the mechanical AVR and the biological AVR cohort.

Results

From May 1985 to April 2020 fifty-five patients received sixty AVRs: 33 mechanical AVRs and 27 biological AVRs. In over half of the fifty-three AVRs performed after 1991 (58.5%; 31/53) a contraindication for Ross procedure was present. Early mortality was 5% (3/60). All early deaths occurred in patients aged < 1 year at time of surgery. Two late deaths occurred and survival was 94.5% ± 3.1% at 10 years and 86.4% ± 6.2% at 30 years. Freedom from aortic valve re-operation was higher (p < 0.001) in the mechanical AVR than in the biological AVR cohort with 95.2% ± 4.6% and 33.6% ± 13.4% freedom from re-operation at 10 years respectively.

Conclusions

Re-operation was less frequent in the mechanical AVR cohort than in the biological AVR cohort. For mechanical AVR, the risk for thromboembolic and bleeding events was considerable with a composite linearized event rate per valve-year of 3.2%.

The Ross procedure in children: a systematic review

Background

The Ross procedure involves autograft transplantation of the native pulmonary valve into the aortic position and reconstruction of the right ventricular outflow tract (RVOT) with a homograft. The operation offers the advantages of a native valve with excellent hemodynamic performance, the avoidance of anticoagulation, and growth potential. Conversely, the operation is technically demanding and imposes the risk of turning single-valve disease into double-valve disease. This systematic review reports outcomes of pediatric patients undergoing the Ross procedure.

Methods

An electronic search identified studies reporting outcomes on pediatric patients (mean age <18 years, max age <21 years) undergoing the Ross procedure. Long-term outcomes, including early mortality, late mortality, sudden unexpected unexplained death, reoperation due to failure of the pulmonary autograft or RVOT reconstruction, thromboembolic events, bleeding events, and endocarditis-related complications, were evaluated.

Results

Upon review of 2,035 publications, 30 studies and 3,156 pediatric patients were included. Patients had a median age of 9.5 years and median follow-up period of 5.7 years. Early mortality rates varied from 0.0 to 17.0% and were increased in the neonatal population. Late mortality rates were much lower (0.04-1.83%/year). Reoperation due to pulmonary autograft failure occurred at rates of 0.37-2.81%/year and reoperation due to RVOT reconstruction failure was required at rates of 0.34-4.76%/year. Thromboembolic, bleeding, and endocarditis events were reported to occur at rates of 0.00-0.58, 0.00-0.39, and 0.00-1.68%/year, respectively.

Conclusions

The Ross operation offers a durable aortic valve replacement (AVR) option in the pediatric population that offers favorable survival, excellent hemodynamics, growth potential, decreased risk of complications, and avoidance of anticoagulation. Larger multi-institutional registries focusing on pediatric patients are necessary to provide more robust evidence to further support use of the Ross procedure in this population.

A geometrically adaptable heart valve replacement

Congenital heart valve disease has life-threatening consequences that warrant early valve replacement; however, the development of a growth-accommodating prosthetic valve has remained elusive. Thousands of children continue to face multiple high-risk open-heart operations to replace valves that they have outgrown. Here, we demonstrate a biomimetic prosthetic valve that is geometrically adaptable to accommodate somatic growth and structural asymmetries within the heart. Inspired by the human venous valve, whose geometry is optimized to preserve functionality across a wide range of constantly varying volume loads and diameters, our balloon-expandable synthetic bileaflet valve analog exhibits similar adaptability to dimensional and shape changes. Benchtop and acute in vivo experiments validated design functionality, and in vivo survival studies in growing sheep demonstrated that mechanical valve expansion accommodated growth. As illustrated in this work, dynamic size adaptability with preservation of unidirectional flow in prosthetic valves thus offers a paradigm shift in the treatment of heart valve disease.

Ross Operation in Neonates: A Meta-analysis

BACKGROUND

The Ross operation is the preferred treatment for aortic valve replacement in children. However previous studies indicate that outcomes in neonates are poor. This meta-analysis examines the pooled outcomes of the Ross operation in neonates.

METHODS

Four major databases (PubMed/MEDLINE, EMBASE, Scopus, and ScienceDirect) were searched from inception until May 1, 2020 for studies describing outcomes of the Ross operation in neonates. The primary outcome was early mortality, and secondary outcomes were late mortality and mechanical support. Random-effects models were used to account for possible heterogeneity between studies, and continuity corrections were used to include zero total event trials.

RESULTS

Eighteen studies comprising outcomes data on 181 neonates were included in the analysis. Meta-analysis showed a pooled early mortality rate of 24% (95% confidence interval, 12%-38%; I² = 52%, P for heterogeneity = .01). Meta-regression analysis showed that more recently published studies reported significantly worse early mortality (P = .03). The pooled incidence of postoperative mechanical support was 15% (95% confidence interval, 5%-28%; I² = 28%, P for heterogeneity = .22). No evidence of publication bias was found according to Egger's test (bias coefficient = 0.21, P = .57).

CONCLUSIONS

The neonatal Ross operation carries a high early mortality rate. The treatment of unrepairable aortic valves in neonates remains an unsolved problem in congenital cardiac surgery.

Evidence-based surgical hypothesis: Partial heart transplantation can deliver growing valve implants for congenital cardiac surgery

Children undergoing congenital cardiac surgery often outgrow the valve implants. These children are thus committed to morbid reoperations for successive exchanges of the vavular implants that they have outgrown. Therefore the holy grail of congenital cardiac surgery is a valve implant that grows with the recipient child. Preserved homografts routinely are used as valve implants, but they do not grow as the child grows because they lose viability during preservation. In contrast, pulmonary autografts and pediatric heart transplants grow with the recipient children. Similarly, partial heart transplantation can deliver growing valve implants for congenital cardiac surgery. Temporary immune suppression would only be needed until the partial heart transplant can be exchanged for an adult-sized prosthetic valve in the grown child.

A national study of the outcome after treatment of critical aortic stenosis in the neonate

OBJECTIVE

This study describes short-term and long-term outcome after treatment of critical valvular aortic stenosis in neonates in a national cohort, with surgical valvotomy as first choice intervention.

METHODS

All neonates in Sweden treated for critical aortic stenosis between 1994 and 2016 were included. Patient files were analysed and cross-checked against the Swedish National Population Registry as of December 2017, giving complete survival data. Diagnosis was confirmed by reviewing echo studies. Critical aortic stenosis was defined as valvular stenosis with duct-dependent systemic circulation or depressed left ventricular function. Primary outcome was all-cause mortality and secondary outcomes were reintervention and aortic valve replacement.

RESULTS

Sixty-one patients were identified (50 boys, 11 girls). Primary treatment was surgical valvotomy in 52 neonates and balloon valvotomy in 6. Median age at initial treatment was 5 days (0-26), and median follow-up time was 10.8 years (0.14-22.6). There was no 30-day mortality but four late deaths. Freedom from reintervention was 66%, 61%, 54%, 49%, and 46% at 1, 5, 10, 15, and 20 years, respectively. Median time to reintervention was 3.4 months (4 days to 17.3 years). Valve replacement was performed in 23 patients (38%).

CONCLUSIONS

Surgical valvotomy is a safe and reliable treatment in these critically ill neonates, with no 30-day mortality and long-term survival of 93% in this national study. At 10 years of age, reintervention was performed in 54% and at end of follow-up 38% had had an aortic valve replacement.

Postoperative morbidity and mortality from aortic valve replacements in 25 cases in Senegal

The purpose is to study the short- and medium-term morbidity and mortality linked to the implantation of an aortic prosthesis during cardiac surgery. This is a longitudinal, retrospective and descriptive study which takes place over a period from January 2017 to March 2020 (38 months) at the level of the thoracic and cardiovascular surgery clinic of the university Hospital Center of Fann in Dakar. All patients who underwent aortic valve replacement during this period were included in the study. A number of the series was 25 patients with a sex ratio of 2.66. The average age of the patients was 29.5 years (8-51 years). In the patients’ history, 19 patients (76%) had a notion of recurrent angina. Exercise dyspnea was the most common functional symptomatology present in 24 patients (96%). In the series, there were 22 cases (88%) of aortic insufficiency of various grades (2 to 4) with 7 cases (28%) associated with mitral insufficiency. We had 3 cases (12%) of aortic stenosis. All patients received surgical management under cardiopulmonary bypass. The average duration of cardiopulmonary bypass was 132 minutes ± 41.21 (53-226 minutes). The average duration of aortic clamping was 101 minutes ± 31.87 (53-164 minutes). The surgical procedures consisted in replacing the aortic valve with a biological prosthesis in one patient (4%) and a mechanical prosthesis in 24 patients (96%). The average length of hospital stay in intensive care was 5 days ± 4.03 (2-20 days). The average length of hospital stay was 20.76 days ± 13.19 (9 to 64 days). The average duration of follow-up was 8.2 months ± 4.57 (1 week - 32 months). During the follow-up, only one patient (4%) had developed infectious endocarditis on prosthesis and only one patient (4%) had a complication related to anticoagulant therapy (antivitamin K) such as gingivorrhagia and melena. We had recorded a single case of death at 6 months, a late mortality of 4%. Aortic valve replacement surgery, by median sternotomy gives satisfactory short- and medium-term results with negligible morbidity and negligible operative mortality.

How Small Is Too Small? Decision-Making and Management of the Small Aortic Root in the Setting of Interrupted Aortic Arch

Interrupted aortic arch is commonly associated with a posterior malalignment ventricular septal defect (VSD) and left ventricular outflow tract (LVOT) hypoplasia. Standard repair is carried out in the neonatal period and includes re-establishing arc continuity and VSD closure. Reintervention on the LVOT for obstruction is a common and an ongoing source of morbidity and mortality. A variety of preoperative echocardiographic measurements have been identified to identify patients at risk for developing LVOT obstruction but an aortic valve annulus dimension (mm) < patient's weight (kg) + 1 mm is a reasonable threshold to identify a patient at increased risk for future LVOT reintervention. Prophylactic direct approaches to prevent future LVOT obstruction include myectomy/myotomy and left-sided placement of the VSD patch but do not reliably prevent late LVOT obstruction. Patients amendable to a biventricular repair but with important LVOT hypoplasia are probably best served with a Yasui operation, either as a primary operation or staged with a Norwood procedure. In the case of complex redo operations, a Ross-Konno provides another valuable option for a durable repair. Though smaller preoperative LVOT structures predict the need for reoperation, careful preoperative planning may minimize the need for LVOT reintervention and improve long-term survival.

Aortic Valve Replacement and the Ross Operation in Children and Young Adults

BACKGROUND

There are several options available for aortic valve replacement (AVR), with few comparative reports in the literature. The optimal choice for AVR in each age group is not clear.

OBJECTIVES

The study sought to report and compare outcomes after AVR in the young using data from a national database.

METHODS

AVR procedures were compared after advanced matching, both in pairs and in a 3-way manner, using a Bayesian dynamic survival model.

RESULTS

A total of 1,501 patients who underwent AVR in the United Kingdom between 2000 and 2012 were included. Of these, 47.8% had a Ross procedure, 37.8% a mechanical AVR, 10.9% a bioprosthesis AVR, and 3.5% a homograft AVR, with Ross patients being significantly younger when compared to the other groups. Overall survival at 12 years was 94.6%. In children, the Ross procedure had a 12.7% higher event-free probability (death or any reintervention) at 10 years when compared to mechanical AVR (p = 0.05). We also compared all procedures except the homograft in a matched population of young adults, where the bioprosthesis had the lowest event-free probability of 78.8%, followed by comparable results in mechanical AVR and Ross, with 86.3% and 89.6%, respectively. Younger age was associated with mortality and pulmonary reintervention in the Ross group and with aortic reintervention in the mechanical AVR. Of all 3 options, only the patients undergoing the Ross procedure approached the survival of the general population.

CONCLUSIONS

AVR in the young achieves good results, with the Ross being overall better suited for this age group, especially in children. Although freedom from aortic valve reintervention is superior after the Ross procedure, the need for homograft reinterventions is an issue to take into account. All methods have advantages and limitations, with reinterventions being an issue in the long term for all, more crucially in smaller children.

Ross-Konno Procedure With Cylinder Mitral Valve Replacement in 49 Days Old Infant

A neonate with antenatally diagnosed severe aortic valve stenosis, left ventricular outflow tract obstruction, left ventricular endocardial fibroelastosis, and severe mixed mitral valve disease was admitted to our center for balloon aortic valvuloplasty. On day 49, we performed a Ross-Konno procedure and mitral valve replacement on the baby, whose weight was 3.4 kg. Right ventricle-to-pulmonary artery continuity was restored with a handmade trileaflet Gore-Tex conduit. We used a handmade cylindrical prosthesis made from decellularized equine pericardium in the mitral position. We observed improvement in left ventricular function and good performance of aortic, pulmonary, and mitral prostheses at four months of follow-up.

Surgical technique: establishing a pre-clinical large animal model to test aortic valve leaflet substitute

To overcome current limitations of valve substitutes and tissue substitutes the technology of tissue engineering (TE) continues to offer new perspectives in congenital cardiac surgery. We report our experiences and results implanting a decellularized TE patch in nine sheep in orthotropic position as aortic valve leaflet substitute. Establishing the animal model, feasibility, cardiopulmonary bypass issues and operative technique are highlighted.

The mid-term outcome of primary open valvotomy for critical aortic stenosis in early infancy - a retrospective single center study over 18 years

Background

The objective of this study was to examine early and long-term results of surgical aortic valvotomy in neonates and infants aged less than four months and to identify predictors of outcome.

Methods

Between August 1994 and April 2012, 83 consecutive patients younger than 4 months of age underwent open heart valvotomy for critical aortic stenosis in our institution. Median age was 17 days (range 0-111 days). We examined clinical records to establish determinants of outcome and illustrate long-term results.

Results

Fifty-six patients (67 %) were neonates. Associated cardiac malformations were found in 24 patients (29 %), including multilevel left heart obstruction in 5. The median follow-up was 4.2 years. The time-related survival rate was 87 and 85 % at 5 and 15 years, respectively. The time-related survival without reintervention was respectively 51, 35 and 18 % at 5, 10 and 15 years. The time-related survival without aortic valve replacement was respectively 67, 54 and 39 % at 5, 10 and 15 years. Ventricular dysfunction (p = 0.04), delayed sternal closure (p = 0.007), endocardial fibroelastosis (p = 0.02) and low z-score of the aortic annulus (p = 0.04) were found predictors of global mortality. Ventricular dysfunction (p = 0.01) and endocardial fibroelastosis (p = 0.04) were found predictors of reintervention.

Conclusions

The experience, in our center, on the management of critical aortic stenosis, shows a low early and late mortality, but the aortic valvotomy is a palliative procedure and we see unfortunately a high rate of reintervention among which the aortic valve replacement. These results suggest to reconsider the use of aortic balloon valvotomy, and particularly for the neonates with a low cardiac output in order to avoid the myocardial stress and the neurological injury due to the cardiopulmonary bypass.

Neonatal Aortic Stenosis Is a Surgical Disease

Neonates with critical aortic stenosis represent a challenging group of patients with severe obstruction at a valvar level and with symptoms of heart failure. If biventricular repair is chosen, open valvotomy (OV) has been firmly established as the most effective initial treatment. In comparison with blind ballooning, OV, with exact splitting of fused commissures and shaving of obstructing nodules, can produce a better valve with a maximum valve orifice, without causing regurgitation. Thus, predictable and consistent early and longer-lasting results in any type of valve morphology are provided. Clearly superior results can be achieved in a tricuspid valve arrangement. OV not only offers a high survival benefit in the long run, but also a high quality of life, by minimizing re-interventions and preserving the native aortic valve in the majority of patients.

The science of assessing the outcomes and improving the quality of the congenital and paediatric cardiac care

PURPOSE OF REVIEW

Although significant progress has been made in the care of patients with paediatric and congenital cardiac disease, optimization of outcomes remains a constant goal. This review article will discuss the latest advances in the science of assessing the outcomes and improving the quality of the congenital and paediatric cardiac care, and will also review some of the latest associated research.

RECENT FINDINGS

Important advances continue to be made in each of the following domains: standardized nomenclature; established uniform core dataset; evaluation of case complexity; verification of the completeness and accuracy of the data; collaboration between subspecialties; strategies for longitudinal follow-up; and incorporating quality improvement. In January 2015, the Society of Thoracic Surgeons Congenital Heart Surgery Database (STS-CHSD) will begin voluntary public reporting of programmatic congenital cardiac surgical outcomes using a new risk model that includes both procedural risk (as defined by the procedure itself and STAT Categories) and a number of patient-specific characteristics including age, weight, prior cardiothoracic operation, prematurity, chromosomal abnormalities, syndromes, noncardiac congenital anatomic abnormalities and preoperative factors. Clinical databases have been linked with administrative database to answer questions neither dataset can answer independently, providing new information about long-term mortality, rates of rehospitalization, long-term morbidity, comparative effectiveness of various treatments, and the cost of healthcare. Multiple research initiatives have recently been published using STS-CHSD.

SUMMARY

The science of assessing the outcomes and improving the quality of congenital and paediatric cardiac care continues to evolve. Recent advances will facilitate the continued evolution of a meaningful method of multiinstitutional outcomes analysis for congenital and paediatric cardiac surgery.

The Ross, Konno, and Ross-Konno operations for congenital left ventricular outflow tract abnormalities

Operations for left ventricular outflow tract abnormalities are centred on hemodynamic conditions that relate to subvalvar stenosis, valvar stenosis/regurgitation, aortic annular hypoplasia, and supravalvar aortic stenosis. Operative interventions over the years have evolved because the intervening outcomes proved to be unsatisfactory. The resection for subvalvar aortic stenosis has progressed from a fibrous "membrane" resection to a more extensive fibromuscular resection. Operative solutions for valvar aortic stenosis and regurgitation have resulted in operative interventions that depend on simple commissurotomy, leaflet extensions, prosthetic mechanical valve replacement, biologic valve replacement, including the pulmonary autograft, and operations to treat aortic annular stenosis. Although there are enthusiastic proponents for all of these strategies, the fact remains that none have proven to be curative; patients can expect to undergo further procedures during their lifetimes. The short- and mid-term solutions to these left ventricular outflow tract abnormalities have improved based on operations that have been attended by increasing operative complexity. The purpose of this review is to chronicle the operative steps of the Ross operation, the Konno-Rastan operation, the modified Konno operation, the Ross-Konno operation, and the modified Ross-Konno operation.

The Ross Operation in Children and Young Adults

Objectives:

To determine UK national trends and results of the Ross operation in relation to all aortic valve interventions.

Methods:

Examination of the UK Congenital Central Cardiac Audit Database for all aortic valve procedures performed between 2000 and 2011 in children (0-16 years) and young adults (16-30 years).

Results:

A total of 2,206 aortic valve procedures were performed in children and 1,824 in young adults, the proportions in the two groups being: Ross operation (19% vs 15%, respectively), surgical valvoplasty (9.5% vs 4%), surgical valvotomy (9.5% vs 1%), aortic valve replacement (AVR; 11% vs 55%), aortic root replacement (4% vs 18%), and balloon valvoplasty (47% vs 7%). The 30-day and 1-year survival after Ross is 99.3% and 98.7%, respectively, in the last four years achieving 100%. In children, the proportion of balloon valvoplasty increased from an average of 43% in 2000 to 2006 to 53% in 2007 to 2011, whereas the Ross operation decreased from 22% to 16% ( P < .001). In young adults, the figures are an increase from 49% to 58% for AVR compared to a decrease from 23% to 9% for Ross ( P < .001). Our own single-center series of 91 patients also shows standard results for early- and long-term survival and freedom from reoperation, but gradually fewer Ross operations performed. The year-on-year changes show a significant decreasing trend locally and nationally.

Conclusions:

Despite an excellent track record, the Ross operation is performed less frequently in the United Kingdom. This report is a first step in comparing treatment modalities at national level.

Mini-Konno procedure using a 10 mm handmade valve for pulmonary atresia with intact ventricular septum and severe aortic stenosis

We herein report the case of a neonate with pulmonary atresia with intact ventricular septum, right ventricular hypoplasia and severe aortic stenosis. Repetitive aortic valve surgeries in early infancy resulted in early relapse of the aortic stenosis due to the small aortic annulus, bicuspid configuration and duct-dependent pulmonary circulation. The infant underwent a successful mini-Konno procedure using a 10 mm handmade valve and bidirectional Glenn shunt at 6 months of age.

Perioperative mechanical circulatory support in children: an analysis of the Society of Thoracic Surgeons Congenital Heart Surgery Database

OBJECTIVES

Analyses of mechanical circulatory support (MCS) in pediatric heart surgery have primarily focused on single-center outcomes or narrow applications. We describe the patterns of use, patient characteristics, and MCS-associated outcomes across a large multicenter cohort.

METHODS

Patients (aged <18 years) in the Society of Thoracic Surgeons (STS) Congenital Heart Surgery Database (2000-2010) were included. The characteristics and outcomes of those receiving postoperative MCS were described, and bayesian hierarchical models were used to examine variations in the adjusted MCS rates across institutions.

RESULTS

Of 96,596 operations (80 centers), MCS was used in 2.4%. The MCS patients were younger (13 vs 195 days, P < .0001) and more often had STS-defined preoperative risk factors (57.2% vs 32.7%, P < .0001). The operations with the greatest MCS rates included the Norwood procedure (17%) and complex biventricular repairs (arterial switch, ventricular septal defect, and arch repair [14%]). More than one half of the MCS patients did not survive to hospital discharge (53.2% vs 2.9% of non-MCS patients; P < .0001). MCS-associated mortality was greatest for truncus arteriosus and Ross-Konno operations (both 71%). The hospital-level MCS rates adjusted for patient characteristics and case mix varied by 15-fold across institutions, with both high- and low-volume hospitals having substantial variation in MCS rates.

CONCLUSIONS

Perioperative MCS use varied widely across centers. The MCS rates were greatest overall for the Norwood procedure and complex biventricular repairs. Although MCS can be a life-saving therapy, more than one half of MCS patients will not survive to hospital discharge, with mortality >70% for some operations. Future studies aimed at better understanding the appropriate indications, optimal timing, and management of MCS could help to reduce the variation in MCS use across hospitals and improve outcomes.

Aortic valve replacement in children: Options and outcomes

Several disease pathologies such as congenital heart disease and rheumatic fever can affect the aortic valve (AV) in children frequently necessitating intervention. While percutaneous or surgical AV repair is recommended as initial management strategy in children with AV disease, AV replacement (AVR) might become necessary in children with significant valve destruction and after repair or intervention failure. AVR in children is associated with distinct clinical and technical problems owing to several anatomic, social and prosthesis-related issues. In the current review, we list different AV substitutes, discuss their advantages and shortcomings, outline AVR results in children, and explore the divergence of outcomes in various age, anatomy and pathology subgroups; all in the aim to identify optimal AVR choice for each patient taking into consideration his unique anatomic and demographic characteristics.