Outcome after aortic valve replacement in children: A systematic review and meta-analysis

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.

Outcomes post Ozaki procedure among children with aortic valve disease at Jakaya Kikwete Cardiac Institute, Dar es Salaam, Tanzania: a retrospective descriptive study

BACKGROUND

Aortic valve reconstruction using glutaraldehyde-treated autologous pericardium, also called Ozaki procedure, is a surgical procedure for patients with aortic valve disease. Gratifying results have been reported in adult patients, however, limited published data is available in paediatric population. This study looked at clinical characteristics and early outcomes of children who underwent Ozaki procedure at our Institute.

METHODS

This was a retrospective descriptive study conducted on children who underwent aortic valve reconstruction at Jakaya Kikwete Cardiac Institute (JKCI) from January 2019 through December 2022. Medical records of these children were reviewed to extract data on demographics, clinical characteristics, redo surgical interventions and survival.

RESULTS

A total of 10 children underwent Ozaki procedure during the study period. Eight children had severe aortic regurgitation while 2 had severe aortic stenosis preoperatively. All children had either none or trivial aortic regurgitation immediately after surgery. None of them had redone operations throughout the follow-up period. There was no in-hospital mortality, however, one child died one-year after surgery. The mean follow-up period was 1.6 years with the longest follow-up time of 4 years.

CONCLUSION

Ozaki procedure showed encouraging early results among children with aortic valve disease who underwent surgical repair by this technique. Future studies with larger sample sizes and longer follow up periods to evaluate long-term results in this population are recommended.

Preservation of human heart valves for replacement in children with heart valve disease: past, present and future

Valvular heart disease affects 30% of the new-borns with congenital heart disease. Valve replacement of semilunar valves by mechanical, bioprosthetic or donor allograft valves is the main treatment approach. However, none of the replacements provides a viable valve that can grow and/or adapt with the growth of the child leading to re-operation throughout life. In this study, we review the impact of donor valve preservation on moving towards a more viable valve alternative for valve replacements in children or young adults.

National experience with pediatric surgical aortic valve repair: A Pediatric Health Information System analysis

OBJECTIVE

To characterize national experience with surgical aortic valve repair in pediatric patients.

METHODS

Patients in the Pediatric Health Information System database aged 17 years or younger with International Statistical Classification of Diseases and Related Health Problems codes for open aortic valve repair from 2003 to 2022 were included (n = 5582). Outcomes of reintervention during index admission (repeat repair, n = 54; replacement, n = 48; and endovascular intervention, n = 1), readmission (n = 2176), and in-hospital mortality (n = 178) were compared. A logistic regression was performed for in-hospital mortality.

RESULTS

One-quarter (26%) of patients were infants. The majority (61%) were boys. Heart failure was present in 16% of patients, congenital heart disease in 73%, and rheumatic disease in 4%. Valve disease was insufficiency in 22% of patients, stenosis in 29%, and mixed in 15%. The highest quartile of centers by volume (median, 101 cases; interquartile range, 55-155 cases) performed half (n = 2768) of cases. Infants had the highest prevalence of reintervention (3%; P < .001), readmission (53%; P < .001), and in-hospital mortality (10%; P < .001). Previously hospitalized patients (median, 6 days; interquartile range, 4-13 days) were at higher risk for reintervention (4%; P < .001), readmission (55%; P < .001), and in-hospital mortality (11%; P < .001), as were patients with heart failure (reintervention [6%; P < .001], readmission [42%; P = .050], and in-hospital mortality [10%; P < .001]). Stenosis was associated with reduced reintervention (1%; P < .001) and readmission (35%; P = .002). The median number of readmissions was 1 (range, 0-6) and time to readmission was 28 days (interquartile range, 7-125 days). A regression of in-hospital mortality identified heart failure (odds ratio, 3.05; 95% CI, 1.59-5.49), inpatient status (odds ratio, 2.40; 95% CI, 1.19-4.82), and infancy (odds ratio, 5.70; 95% CI, 2.60-12.46) as significant.

CONCLUSIONS

The Pediatric Health Information System cohort demonstrated success with aortic valve repair; however, early mortality remains high in infants, hospitalized patients, and patients with heart failure.

Long-Term Outcomes of Mechanical Aortic Valve Replacement in Children

When the options of aortic valve repair or the Ross procedure are not feasible or have been exhausted, mechanical aortic valve replacement (AVR) may provide a reliable and structurally durable alternative, but with the limitations of long-term anticoagulation, thrombosis risk and lack of valve growth potential. In this article, we review the longitudinal outcomes of mechanical AVR in children in our institution and compare them to those recently reported by others. From 1978 to 2020, 62 patients underwent mechanical AVR at a median age of 12.4 years (interquartile range (IQR): 8.6-16.8 years). The most common underlying diagnoses were: conotruncal anomalies (40%, 25/62), congenital aortic stenosis (16%, 10/62), rheumatic valve disease (16%, 10/62), connective tissue disease (8.1%, 5/62) and infective endocarditis (6.5%, 4/62). Thirty-two patients (52%, 32/62) had at least 1 prior aortic valve surgery prior to mechanical AVR. Early death was 3.2% (2/62). Median follow-up was 14.4 years (IQR: 8.4-28.2 years). Kaplan-Meier survival was 96.8%, 91.9%, 86.3%, and 81.9% at 1, 5, 10, and 20 years. On competing risk analysis, the proportion of patients alive without aortic valve reoperation at 1, 5, 10, and 20 years was 95.2%, 87.0%, 75.5% and 55.4%, respectively, while the proportion of patients that had aortic valve reoperation (with death as a competing event) at 1, 5, 10, and 20 years was 1.6%, 4.9%, 12.8%, and 28.5%, respectively. In conclusion, when the options of aortic valve repair or the Ross procedure are not feasible in children, mechanical AVR is an alternative, yet the long-term rates of mortality and need for aortic valve reoperation are of concern.

Outcomes after Mechanical Aortic Valve Replacement in Children with Congenital Heart Disease

Background

The optimal choice of valve substitute for aortic valve replacement (AVR) in pediatric patients remains a matter of debate. This study investigated the outcomes following AVR using mechanical prostheses in children.

Methods

Forty-four patients younger than 15 years who underwent mechanical AVR from March 1990 through March 2023 were included. The outcomes of interest were death or transplantation, hemorrhagic or thromboembolic events, and reoperation after mechanical AVR. Adverse events included any death, transplant, aortic valve reoperation, and major thromboembolic or hemorrhagic event.

Results

The median age and weight at AVR were 139 months and 32 kg, respectively. The median follow-up duration was 56 months. The most commonly used valve size was 21 mm (14 [31.8%]). There were 2 in-hospital deaths, 1 in-hospital transplant, and 1 late death. The overall survival rates at 1 and 10 years post-AVR were 92.9% and 90.0%, respectively. Aortic valve reoperation was required in 4 patients at a median of 70 months post-AVR. No major hemorrhagic or thromboembolic events occurred. The 5- and 10-year adverse event-free survival rates were 81.8% and 72.2%, respectively. In univariable analysis, younger age, longer cardiopulmonary bypass time, and smaller valve size were associated with adverse events. The cut-off values for age and prosthetic valve size to minimize the risk of adverse events were 71 months and 20 mm, respectively.

Conclusion

Mechanical AVR could be performed safely in children. Younger age, longer cardiopulmonary bypass time and smaller valve size were associated with adverse events. Thromboembolic or hemorrhagic complications might rarely occur.

Aortic valve repair versus the Ross procedure in children

BACKGROUND

Aortic valve repair and the Ross procedure are widely used in children; however, it is unclear which provides the best outcomes.

METHODS

Patients who underwent primary aortic valve surgery from 1980 to 2018 were included. Propensity score matching was performed to adjust for baseline differences.

RESULTS

Of 415 children, 82.7% (343/415) underwent repair and 17.3% (72/415) underwent the Ross procedure. At 15 years, survival was higher for aortic valve repair (93.9% ± 1.8% vs 80.9% ± 6.4%, P = .04); freedom from reoperation (45.7% ± 4.9% vs 48.5% ± 9.0%, P = .29) did not differ, and freedom from aortic valve reoperation was higher in the Ross procedure group (45.7% ± 4.9% vs 70.7% ± 8.0%, P < .001). When analyzed by quality of repair, acceptable repair provided the highest survival (P = .01). Acceptable repair and the Ross procedure had similar freedom from reoperation at 15 years, whereas suboptimal repair performed worse (acceptable: 54.9% ± 6.7%; Ross procedure: 48.5% ± 9.0%; suboptimal: 27.0% ± 7.7%, P < .001). Acceptable repair and the Ross procedure had similar freedom from aortic valve reoperation at 15 years, whereas suboptimal repair showed worse results (acceptable: 54.9 ± 6.7; Ross procedure: 70.7% ± 8.0%; suboptimal: 27.0% ± 7.7%, P < .001). Propensity score matching paired 66 patients who underwent the Ross procedure with 198 patients who underwent repair. At 15 years, repair was associated with better survival (98.0% ± 1.2% vs 78.5% ± 7.2%, P = .03), whereas freedom from reoperation was similar (42.6% ± 7.6% vs 50.7% ± 9.8%, P = .50). However, the Ross procedure was associated with higher freedom from aortic valve reoperation (42.6% ± 7.6% vs 72.3% ± 8.5%, P = .002).

CONCLUSIONS

Primary aortic valve repair was associated with better survival than the Ross procedure, whereas overall freedom from reoperation was similar. When an acceptable intraoperative result was achieved, outcomes of repair were favorable. However, when the intraoperative result of repair was suboptimal, the Ross procedure showed better results.

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.

Paediatric aortic valve replacement: a meta-analysis and microsimulation study

AIMS

To support decision-making in children undergoing aortic valve replacement (AVR), by providing a comprehensive overview of published outcomes after paediatric AVR, and microsimulation-based age-specific estimates of outcome with different valve substitutes.

METHODS AND RESULTS

A systematic review of published literature reporting clinical outcome after paediatric AVR (mean age <18 years) published between 1/1/1990 and 11/08/2021 was conducted. Publications reporting outcome after paediatric Ross procedure, mechanical AVR (mAVR), homograft AVR (hAVR), and/or bioprosthetic AVR were considered for inclusion. Early risks (<30d), late event rates (>30d) and time-to-event data were pooled and entered into a microsimulation model. Sixty-eight studies, of which one prospective and 67 retrospective cohort studies, were included, encompassing a total of 5259 patients (37 435 patient-years; median follow-up: 5.9 years; range 1-21 years). Pooled mean age for the Ross procedure, mAVR, and hAVR was 9.2 ± 5.6, 13.0 ± 3.4, and 8.4 ± 5.4 years, respectively. Pooled early mortality for the Ross procedure, mAVR, and hAVR was 3.7% (95% CI, 3.0%-4.7%), 7.0% (5.1%-9.6%), and 10.6% (6.6%-17.0%), respectively, and late mortality rate was 0.5%/year (0.4%-0.7%/year), 1.0%/year (0.6%-1.5%/year), and 1.4%/year (0.8%-2.5%/year), respectively. Microsimulation-based mean life-expectancy in the first 20 years was 18.9 years (18.6-19.1 years) after Ross (relative life-expectancy: 94.8%) and 17.0 years (16.5-17.6 years) after mAVR (relative life-expectancy: 86.3%). Microsimulation-based 20-year risk of aortic valve reintervention was 42.0% (95% CI: 39.6%-44.6%) after Ross and 17.8% (95% CI: 17.0%-19.4%) after mAVR.

CONCLUSION

Results of paediatric AVR are currently suboptimal with substantial mortality especially in the very young with considerable reintervention hazards for all valve substitutes, but the Ross procedure provides a survival benefit over mAVR. Pros and cons of substitutes should be carefully weighed during paediatric valve selection.

Aortic valve repair in neonates, infants and children: a systematic review, meta-analysis and microsimulation study

OBJECTIVES

To support clinical decision-making in children with aortic valve disease, by compiling the available evidence on outcome after paediatric aortic valve repair (AVr).

METHODS

A systematic review of literature reporting clinical outcome after paediatric AVr (mean age at surgery <18 years) published between 1 January 1990 and 23 December 2021 was conducted. Early event risks, late event rates and time-to-event data were pooled. A microsimulation model was employed to simulate the lives of individual children, infants and neonates following AVr.

RESULTS

Forty-one publications were included, encompassing 2 623 patients with 17 217 patient-years of follow-up (median follow-up: 7.3 years; range: 1.0-14.4 years). Pooled mean age during repair for aortic stenosis in children (<18 years), infants (<1 year) or neonates (<30 days) was 5.2 ± 3.9 years, 35 ± 137 days and 11 ± 6 days, respectively. Pooled early mortality after stenosis repair in children, infants and neonates, respectively, was 3.5% (95% confidence interval: 1.9-6.5%), 7.4% (4.2-13.0%) and 10.7% (6.8-16.9%). Pooled late reintervention rate after stenosis repair in children, infants and neonates, respectively, was 3.31%/year (1.66-6.63%/year), 6.84%/year (3.95-11.83%/year) and 6.32%/year (3.04-13.15%/year); endocarditis 0.07%/year (0.03-0.21%/year), 0.23%/year (0.07-0.71%/year) and 0.49%/year (0.18-1.29%/year); and valve thrombosis 0.05%/year (0.01-0.26%/year), 0.15%/year (0.04-0.53%/year) and 0.19%/year (0.05-0.77%/year). Microsimulation-based mean life expectancy in the first 20 years for children, infants and neonates with aortic stenosis, respectively, was 18.4 years (95% credible interval: 18.1-18.7 years; relative survival compared to the matched general population: 92.2%), 16.8 years (16.5-17.0 years; relative survival: 84.2%) and 15.9 years (14.8-17.0 years; relative survival: 80.1%). Microsimulation-based 20-year risk of reintervention in children, infants and neonates, respectively, was 75.2% (72.9-77.2%), 53.8% (51.9-55.7%) and 50.8% (47.0-57.6%).

CONCLUSIONS

Long-term outcomes after paediatric AVr for stenosis are satisfactory and dependent on age at surgery. Despite a high hazard of reintervention for valve dysfunction and slightly impaired survival relative to the general population, AVr is associated with low valve-related event occurrences and should be considered in children with aortic valve disease.

Effectiveness and Safety of the Ozaki Procedure for Aortic Valve Disease in Pediatric Patients: A Systematic Review and Meta-Analysis

The surgical treatment options for pediatric aortic valve disease are limited and have debatable long-term durability. In the current situation, the Ross procedure is considered in children for aortic valve disease(s). It is a complex surgical procedure with the risk of neo-aortic dilatation, converting a single valve disease into double valve disease, and associated with future re-interventions. Conversely, the Ozaki procedure has shown promising results in adults. Thus, the present study aimed to provide comparative evidence on the effectiveness and safety of the Ozaki versus Ross procedure for pediatric patients by performing a meta-analytic comparison of reporting outcomes. A total of 15 relevant articles were downloaded and among them, seven articles (one prospective study, five retrospective studies, and one case series) were used in the analysis. Primary outcomes such as physiological laminar flow pattern and hemodynamic parameters, and secondary outcomes such as hospital stays, adverse effects, mortality, and numbers of re-intervention(s) were measured in the meta-analysis. There were no significant differences in the age of patients between children who underwent the Ozaki procedure and those who underwent the Ross procedure at the time of surgeries. The Ozaki procedure is a good solution to an aortic problem(s) similar to the Ross procedure. Unlike the Ross procedure, the Ozaki procedure has restored a physiological laminar flow pattern in the short-term follow-up without the bi-valvular disease. Mean hospital stays (p = 0.048), mean follow-up (p = 0.02), adverse effects (p = 0.02), death, and numbers of re-intervention(s) of children who underwent the Ozaki procedure were fewer than those who underwent the Ross procedure. The time required for re-intervention(s) is higher for children who underwent the Ozaki procedure than those who underwent the Ross procedure. None of the procedures, including the Ozaki procedure for aortic valve disease(s), has significant effects on hemodynamic parameters and the frequent death rate of children after surgeries. Based on our analysis, we may suggest the Ozaki procedure for aortic valve disease surgery in children.

Ross procedure versus pulmonary homograft versus mechanical valve versus bioprosthetic valve versus Ozaki procedure for surgical aortic valve replacement: a frequentist network meta-analysis

BACKGROUND

There has been a resurgence in interest regarding the Ross procedure due to recent publications detailing positive long-term outcomes. Conversely, surgical aortic valve replacement (SAVR) with a pulmonary homograft (PH), mechanical (MV), bioprosthetic (BV), or the Ozaki procedure each has its own technical advantages and disadvantages. Therefore, we performed a network meta-analysis (NMA) comparing other alternatives to Ross procedure.

METHODS

Medical databases were comprehensively searched for studies comparing the Ross procedure with AVR using a PH, MV, BV, or the Ozaki procedure. Outcomes were pooled as risk ratios (RR) with their 95% confidence intervals (95% CI).

RESULTS

A total of 7816 patients were pooled for our NMA from 24 studies. Compared to Ross procedure, both BV and MV were associated with significantly higher rates of 30-day mortality of RR (2.37, 95% CI 1.20-4.67) and (1.88 95% CI 1.04-3.40), respectively, with no significant difference regarding PH or Ozaki. However, only MV was associated with a higher risk of 30-day stroke (RR 8.42, 95% CI 1.57-45.23) with no significant difference in the other alternatives, as well as 30-day MI which showed no significant differences between any of the aortic conduits compared to the Ross procedure. Regarding 30-day major bleeding, MV was associated with a higher when compared to the Ross procedure RR (4.58, 95% CI 1.94-10.85), PH was associated with a lower risk of major bleeding with RR (0.35, 95% CI 0.17-0.71), and BV showed no significant difference. With a mean follow-up duration of 8.5 years compared to the Ross procedure, BV, PH, and MV were associated with a higher risk of long-term mortality with RR (1.89, 95% CI 1.38-2.58), (1.38, 95% CI 1.0-1.87), and (1.94, 95% CI 1.52-2.47), respectively, with the Ozaki procedure showed no significant difference. Regarding long-term stroke-with a mean of 6.3-year follow-up duration-there were no significant differences between any of the aortic conduits compared to the Ross procedure. Nevertheless, long-term need for reintervention-with a mean follow-up duration of 17.5 years-was significant of higher risk with both BV and PH with RR (3.28, 95% CI 1.21-8.84) and (2.42, 95% CI 1.05-5.58), respectively, compared to Ross procedure with MV and Ozaki having no significant difference.

CONCLUSIONS

The Ross procedure is a viable treatment option for patients undergoing SAVR, showing promising outcomes at short- and long-term follow-ups.

The Ross Procedure in Children: Defining the Optimal Age

BACKGROUND

It has been proposed that delaying the Ross procedure to later in childhood, allowing autograft stabilisation and placement of a larger pulmonary conduit, may improve outcomes. However, the effect of age at the time of Ross procedure on outcomes remains unclear.

METHODS

All patients who underwent the Ross procedure between 1995 and 2018 were included in the study. Patients were divided into four groups: infants, age 1 to 5 years, age 5 to 10 years and age 10 to 18 years.

RESULTS

A total of 140 patients underwent the Ross procedure in the study period. Early mortality was 23.3% (7/30) for infants compared to 0% for older children (p<0.001). Survival at 15 years was significantly lower in infants (76.3%±9.9%), compared to children aged 1 to 5 years (90.9%±20.1%), 5 to 10 years (94%±13.3%), and 10 to 18 years (86.7%±10.0%), p=0.01. Freedom from autograft reoperation at 15 years was significantly lower in infants (58.4%±16.2%), compared to children aged 1 to 5 years (77.1%±14.9%), 5 to 10 years (84.2%±6.0%) and 10 to 18 years (87.8%±9.0%), p=0.01. Overall freedom from reoperation at 15 years was 13.0%±6.0% for infants, 24.2%±9.0% for children aged 1 to 5 years, 46.7%±15.8% for children aged 5 to 10 years, and 78.4%±10.4%, p<0.001.

CONCLUSIONS

The Ross procedure performed after 10 years of age appears to be associated with improved freedom from reoperation, primarily due to a reduction in reoperation on the pulmonary conduit.

Outcomes of truncal valve replacement in neonates and infants: a meta-analysis

BACKGROUND

Infants with truncus arteriosus typically undergo repair by repurposing the truncal valve as the neo-aortic valve and using a valved conduit homograft for the neo-pulmonary valve. In cases where the native truncal valve is too insufficient for repair, it is replaced, but this is a rare occurrence with a paucity of data, especially in the infant population. Here, we conduct a meta-analysis to better understand the outcomes of infant truncal valve replacement during the primary repair of truncus arteriosus.

METHODS

We systematically reviewed PubMed, Scopus, and CINAHL for all studies reporting infant (<12 months) truncus arteriosus outcomes between 1974 and 2021. Exclusion criteria were studies which did not report truncal valve replacement outcomes separately. Data extracted included valve replacement type, mortality, and reintervention. Our primary outcome was early mortality, and our secondary outcomes were late mortality and reintervention rates.

RESULTS

Sixteen studies with 41 infants who underwent truncal valve replacement were included. The truncal valve replacement types were homografts (68.8%), mechanical valves (28.1%), and bioprosthetic valves (3.1%). Overall early mortality was 49.4% (95% CI: 28.4-70.5). The pooled late mortality rate was 15.3%/year (95% CI: 5.8-40.7). The overall rate of truncal valve reintervention was 21.7%/year (95% CI: 8.4-55.7).

CONCLUSIONS

Infant truncal valve replacement has poor early and late mortality as well as high rates of reintervention. Truncal valve replacement therefore remains an unsolved problem in congenital cardiac surgery. Innovations in congenital cardiac surgery, such as partial heart transplantation, are required to address this.

Aortic valve repair in the pediatric population: emerging role of aortic valve neocuspidization (AVNeo procedure)

Management of aortic valve diseases in children is challenging owing to the quality and quantity of the native tissue for repair, limitations in the currently available biological materials to supplement the repair and to achieve a long-lasting durable repair in an annulus where there is still growth potential. The aortic valve neocuspidization (AVNeo) procedure has emerged as a versatile alternative strategy in the armamentarium of pediatric aortic valve reconstructions that are currently available. In this review article, the focus of the discussion will be on the various aortic valve repair procedures in the pediatric population, with a special emphasis on the emerging role of AVNeo procedure in pediatrics and its outcomes.

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.

Complexity and Outcome of Reoperations After the Ross Procedure in the Current Era

BACKGROUND

The Ross procedure has several advantages, but the need for reintervention is inevitable. The aim of this study was to examine the complexity and outcomes of reoperation after the Ross procedure.

METHODS

Retrospective chart review was performed of patients with a prior Ross procedure who underwent reoperation at our institution from September 1991 to January 2021. Demographic, echocardiographic, surgical, and perioperative data were collected. Descriptive statistical and regression analyses were performed.

RESULTS

A total of 105 patients underwent a reoperation at Mayo Clinic after the initial Ross procedure performed at our institution (n = 16; 16.2%) or elsewhere (n = 83; 83.8%). Mean age at the Ross procedure was 27 ± 17 years, and mean age at reoperation at our institution was 37 ± 19 years. Indications for surgical procedure varied, but 64% had autograft regurgitation as 1 of their indications for reoperation. Autograft interventions were performed in 78 patients (74.2%). Pulmonary valve or conduit replacement was performed in 56 patients (53.3%). Double root replacement was performed in 11 patients (10.5%). Aortic reconstruction was performed in 37 patients (38.4%). There were 5 early deaths (5%). During a median follow-up of 6.25 years (3 months-24 years), late deaths occurred in 14 patients (13.1%). Patients with ejection fraction <30% on preoperative echocardiography had shorter duration between the Ross procedure and subsequent reoperation (P = .03).

CONCLUSIONS

Reoperations after the Ross procedure are performed for a wide range of indications, with most due to autograft dysfunction. The number of early deaths is not low. Reoperation after the Ross procedure should be advised before left ventricular systolic dysfunction.

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.

Evaluation of TTK Chitra heart valve prosthesis in pediatric patients

This report highlights the outcome of valve replacement using TTK Chitra heart mechanical valve in a subgroup of pediatric patients This cohort of 27 pediatric patients with implantations during January 2006 to December 2018 was followed up prospectively. The cohort consisted of 12 aortic valve replacement (AVR), 14 mitral valve replacement (MVR), and 1 double valve replacement (DVR) patients. Total follow-up was 254 patient-years (AVR = 107, MVR = 136, DVR = 11) being 90% complete. The results show that the survival rates and event-free rates were satisfactory. Despite many reservations due to the high risk involved, the long-term benefits of having a durable valve replacement seem to outweigh the risks and offer acceptable long-term survival.

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.

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].

Decellularized bovine jugular vein and hand-sewn ePTFE valved conduit for right ventricular outflow tract reconstruction in children undergoing Ross procedure

Background

The Ross procedure is recommended as an optimal aortic valve replacement (AVR) in children and young adults due to several advantages. Nevertheless, multiple reconstructions of the right ventricular outflow tract (RVOT) with new valve conduits have caused some concern regarding the durability of the Ross AVR. Decellularized bovine jugular vein conduit (BJVC) (DP-BJVC) and hand-sewn expanded polytetrafluoroethylene valved conduits (ePTFE VC) are widely employed to reconstruct the RVOT with satisfactory long-term outcomes. However, few studies have compared the safety and efficacy between the two valve conduits. We aimed to evaluate the early outcomes and report our single center experience in the application of these conduits.

Methods

Twenty-two pediatric patients (aged &lt; 18 years) who underwent Ross procedures with DP-BJVC and ePTFE VC in our center between 1 June, 2017 and 31 January, 2022 were enrolled. The Kaplan–Meier method was used to evaluate survival, freedom from RVOT reintervention, and freedom from RVOT graft dysfunction. Mixed-effects analysis with the Geisser–Greenhouse correction and Sidak's multiple comparisons test for post-hoc analysis was employed to compare the peak gradient across the conduit at varying follow-ups.

Results

All patients were followed up in full. The total early survival rate was 90.9%; two patients in the DP-BJVC group died. There was no significant difference in early mortality, cross-clamp time (p = 0.212), in-hospital stay (p = 0.469), and RVOT graft thrombosis or endocarditis between the two groups. There was similarly no significant difference between Kaplan–Meier freedom from RVOT graft dysfunction curve (P = 0.131). The transprosthetic gradient gradually increased over time in both groups and was significantly higher in the DP-BJVC group at follow-up (P &lt; 0.05).

Conclusions

Both conduits show excellent early and midterm outcomes for RVOT reconstruction in the Ross procedure. We suggest that DP-BJVC is more suitable for infants, and ePTFE conduit is more suitable for older children who require larger conduits.

Surgical Management of Complex Aortic Valve Disease in Young Adults: Repair, Replacement, and Future Alternatives

The ideal aortic valve substitute in young adults remains unknown. Prosthetic valves are associated with a suboptimal survival and carry a significant risk of valve-related complications in young patients, mainly reinterventions with tissue valves and, thromboembolic events and major bleeding with mechanical prostheses. The Ross procedure is the only substitute that restores a survival curve similar to that of a matched general population, and permits a normal life without functional limitations. Though the risk of reintervention is the Achilles' heel of this procedure, it is very low in patients with aortic stenosis and can be mitigated in patients with aortic regurgitation by tailored surgical techniques. Finally, the Ozaki procedure and the transcatheter aortic valve implantation are seen by many as future alternatives but lack evidence and long-term follow-up in this specific patient population.

Natural Polymers in Heart Valve Tissue Engineering: Strategies, Advances and Challenges

In the history of biomedicine and biomedical devices, heart valve manufacturing techniques have undergone a spectacular evolution. However, important limitations in the development and use of these devices are known and heart valve tissue engineering has proven to be the solution to the problems faced by mechanical and prosthetic valves. The new generation of heart valves developed by tissue engineering has the ability to repair, reshape and regenerate cardiac tissue. Achieving a sustainable and functional tissue-engineered heart valve (TEHV) requires deep understanding of the complex interactions that occur among valve cells, the extracellular matrix (ECM) and the mechanical environment. Starting from this idea, the review presents a comprehensive overview related not only to the structural components of the heart valve, such as cells sources, potential materials and scaffolds fabrication, but also to the advances in the development of heart valve replacements. The focus of the review is on the recent achievements concerning the utilization of natural polymers (polysaccharides and proteins) in TEHV; thus, their extensive presentation is provided. In addition, the technological progresses in heart valve tissue engineering (HVTE) are shown, with several inherent challenges and limitations. The available strategies to design, validate and remodel heart valves are discussed in depth by a comparative analysis of in vitro, in vivo (pre-clinical models) and in situ (clinical translation) tissue engineering studies.

Peri-operative changes in diastolic function and outcomes in congenital aortic valve surgery

Background

The ratio of early diastolic mitral inflow velocity (E) to early diastolic mitral annular tissue velocity (e’), or E/e’, is an echocardiographic measure of left ventricular filling pressure. Peri‐operative changes in E/e’ and association with outcomes have been demonstrated in adults undergoing surgery for aortic stenosis (AS). We sought to explore changes in E/e’ and other diastolic indices in the setting of congenital AS surgery and to assess for association with post‐operative outcomes among children and young adults.

Methods

A retrospective, single‐center study was performed among patients 6 months to 30 years of age who underwent congenital AS surgery from 2006 to 2018. Tissue Doppler indices were collected from pre‐ and post‐operative echocardiograms. Post‐operative outcomes were reviewed.

Results

Sixty‐six subjects with subvalvar (45%), valvar (47%), and supravalvar (8%) AS underwent surgery at a median age of 9.5 years (IQR: 4.0–14.8). Pre‐operatively, the lateral E/e’ ratio was 8.6 (6.7–11.0); 33% had E/e’≥10. Post‐operatively, the lateral e’ decreased to 9.9 cm/s (8.0–11.4), the E/e’ ratio increased to 10.4 (8.3–13.1); and 53% had E/e’≥10 (p‐values < 0.0001, 0.0072, and < 0.001, respectively). Pre‐operative lateral e’ correlated modestly with duration of intubation (ρ = −0.24, p‐value 0.048) and post‐operative lateral e’ correlated modestly with duration of intubation and length of hospital stay (ρ = −0.28 and −0.26, p‐values = 0.02 and 0.04, respectively).

Conclusions

Children and young adults who underwent congenital AS surgery had echocardiographic evidence of diastolic dysfunction pre‐operatively that worsened post‐operatively. Lateral e’ may be a sensitive indicator of impaired ventricular relaxation in these patients and may impact duration of intubation and hospital stay.

Louis J, Raghuveer G, Kochilas L. Are Mechanical Prostheses Valid Alternatives to the Ross Procedure in Young Children Under 6 Years Old?

BACKGROUND

Aortic valve replacement in young children is associated with technical difficulties and potential morbidity. In contrast to the versatile Ross operation, mechanical prostheses (MP) are uncommonly used.

METHODS

We examined transplant-free survival and cardiac reoperation among 124 young children (aged 1-6 years) who underwent the Ross operation (n = 84) or MP (n = 40) for congenital disease (1982-2003) using the Pediatric Cardiac Care Consortium database. We explored variables influencing outcomes.

RESULTS

Children who received MP were operated in an earlier era and were more likely to have aortic regurgitation, conotruncal abnormalities, prior aortic valve surgery, and to need Konno annular enlargement. Although no significant differences were found in hospital mortality (1.2% vs 5.0%, P = .24) or 15-year transplant-free survival (94.1% vs 87.5%, P = .16) between Ross and MP recipients, survival diverged with later follow-up (91.3% vs 68.9%, respectively, at 25 years; P = .01). On multivariable regression analysis the association of MP use and transplant-free survival changed over time (hazard ratios, 0.8 [95% confidence interval, 0.1-4.4; P = .78] vs 6.0 [95% confidence interval, 0.6-63.1; P = .13], respectively) before and after 17 years. Cumulative incidence of cardiac reoperation at 10 years was 37.7% and 53.6% after the Ross procedure and MP, respectively (P = .05). The most common reoperation after the Ross procedure was conduit replacement and pacemaker ± automated internal cardiac defibrillator and after MP was pacemaker ± automated internal cardiac defibrillator and redo aortic valve replacement.

CONCLUSIONS

Over the study period there was a trend for increased Ross utilization. Interestingly MP use was associated with comparable operative mortality and survival up to 17 years, albeit with higher need for redo aortic valve replacement. On longer follow-up survival diverged with increased attrition in the MP group, likely because of late valve- and reoperation-related complications.

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.

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.

Multicentre comparative analysis of long-term outcomes after aortic valve replacement in children

OBJECTIVE

The ideal valve substitute for surgical intervention of congenital aortic valve disease in children remains unclear. Data on outcomes beyond 10-15 years after valve replacement are limited but important for evaluating substitute longevity. We aimed to describe up to 25-year death/cardiac transplant by type of valve substitute and assess the potential impact of treatment centre. Our hypothesis was that patients with pulmonic valve autograft would have better survival than mechanical prosthetic.

METHODS

This is a retrospective cohort study from the Pediatric Cardiac Care Consortium, a multi-institutional US-based registry of paediatric cardiac interventions, linked with the National Death Index and United Network for Organ Sharing through 2019. Children (0-20 years old) receiving aortic valve replacement (AVR) from 1982 to 2003 were identified. Kaplan-Meier transplant-free survival was calculated, and Cox proportional hazard models estimated hazard ratios for mechanical AVR (M-AVR) versus pulmonic valve autograft.

RESULTS

Among 911 children, the median age at AVR was 13.4 years (IQR=8.4-16.5) and 73% were male. There were 10 cardiac transplants and 153 deaths, 5 after transplant. The 25-year transplant-free survival post AVR was 87.1% for autograft vs 76.2% for M-AVR and 72.0% for tissue (bioprosthetic or homograft). After adjustment, M-AVR remained related to increased mortality/transplant versus autograft (HR=1.9, 95% CI=1.1 to 3.4). Surprisingly, survival for patients with M-AVR, but not autograft, was lower for those treated in centres with higher in-hospital mortality.

CONCLUSION

Pulmonic valve autograft provides the best long-term outcomes for children with aortic valve disease, but AVR results may depend on a centre's experience or patient selection.

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%.

Aortic valve neocuspidalization in paediatric patients with isolated aortic valve disease: early experience

OBJECTIVES

There is growing interest in the aortic valve (AV) neocuspidalization technique for the treatment of aortic valve disease (AVD). We report our medium-term results with this procedure performed in a paediatric patient population.

METHODS

Between July 2016 and May 2020, 22 patients with both congenital and acquired isolated AVD were treated with neocuspidalization. The primary outcome was progression of the preoperatively assessed AVD in the immediate postoperative course and at follow-up. Secondary outcome was freedom from reintervention by material used. Potential predictors of failure were analysed in relation to the primary outcome.

RESULTS

The median age at operation was 13.9 (interquartile range, 9.8-16.2) years, and the prevailing AV defect was stenosis in 10 cases (45%) and incompetence in 12 (55%). Pre-treated autologous pericardium was used in 13 patients whereas bovine pericardium in 9. Effective treatment of AV stenosis or regurgitation was achieved and remained stable over a median follow-up of 11.3 (4.7-21) months. Three patients required AV replacement at 4.9, 3.5 and 33 months. At follow-up, an upward trend of both median indexed vena contracta jet widths and aortic peak and mean gradients were recorded, the latter associated with a failure to grow the aortic annulus. Predictor of such outcome turned out to be the use of bovine pericardium. A significant inverse linear correlation between AV peak gradient at follow-up and preoperative aortic annular size (P = 0.008) was also demonstrated.

CONCLUSIONS

The Ozaki procedure is safe and effective in paediatric patients with AV disease. The use of heterologous pericardium should probably be minimized. Moreover, preoperative small aortic annuli should probably be promptly treated by means of an associated ring enlargement procedure.

Unicuspid aortic valve repair with bicuspidization in the paediatric population

OBJECTIVES

Aortic stenosis or regurgitation that requires operations in children often results from unicuspid valve morphology. In all paediatric patients with this anomaly, we have performed unicuspid valve repair by bicuspidization, creating a new commissure via adding patch material. This study reviewed our experience with this procedure.

METHODS

All patients with a unicuspid aortic valve who underwent bicuspidization at ≤18 years of age between 2003 and 2018 were evaluated. Autologous pericardium had initially been used for cusp augmentation. Since 2014, decellularized xenogeneic tissue or expanded polytetrafluoroethylene membrane has been applied.

RESULTS

There were 60 consecutive patients. The median operative age was 13 (1-18) years. Thirty patients had prior surgical or catheter valvuloplasties. Aortic regurgitation, aortic stenosis and their combination were present in 22, 11 and 27 patients, respectively. Autologous pericardium decellularized tissue and expanded polytetrafluoroethylene were used in 45, 11 and 4 patients, respectively, without intraoperative conversion to valve replacement. The overall survival was 96% at 10 years with 2 late deaths. Twenty patients underwent aortic valve reoperation due to patch degeneration (n = 11), suture dehiscence of the patch (n = 3), subaortic stenosis (n = 3) or other reasons (n = 3). Freedom from aortic valve reoperation was 73% and 50% at 5 and 10 years, respectively. Fifteen patients (25%) required valve replacement with pulmonary autograft (n = 14) or prosthesis (n = 1) 5.2 (0.2-13) years after bicuspidization at the age of 19 (10-32) years.

CONCLUSIONS

Bicuspidization is a safe and reproducible alternative to valve replacement with acceptable freedom from reoperation. It can serve as a bridge to valve replacement providing superior outcomes in adults.

Paediatric aortic valve replacement using decellularized allografts

OBJECTIVES

Options for paediatric aortic valve replacement (AVR) are limited if valve repair is not feasible. Results of paediatric Ross procedures are inferior to adult Ross results, and mechanical AVR imposes constant anticoagulation with the inherent risks.

METHODS

The study design was a prospective, multicentre follow-up of all paediatric patients receiving decellularized aortic homografts (DAHs) for AVR in 8 European centres.

RESULTS

A total of 106 children (77 boys) were operated (mean age 10.1 ± 4.8 years, DAH diameter 20.5 ± 3.8 mm). A total of 60 (57%) had undergone previous surgical interventions: 34 with 1, 15 with 2 and 11 with ≥3. There was one early death in a 12-year-old girl, who underwent her fourth aortic valve operation, due to intracerebral haemorrhage on extracorporeal membrane oxygenation after coronary reimplantation problems following 3-sinus reconstruction 1 year earlier. One 2-year-old patient died due to sepsis 2 months postoperatively with no evidence for endocarditis. In addition, a single pacemaker implantation was necessary and a 2.5-year-old girl underwent successful HTx due to chronic myocardial failure despite an intact DAH. After a mean follow-up of 3.30 ± 2.45 years, primary efficacy end points mean peak gradient (18.1 ± 20.9 mmHg) and regurgitation (mean 0.61 ± 0.63, grade 0-3) were very good. Freedom from death/explantation/endocarditis/bleeding/stroke at 5 years was 97.8 ± 1.6/85.0 ± 7.4/100/100/100% respectively. Calculated expected adverse events were lower for DAH compared to cryopreserved homograft patients (mean age 8.9 years), lower than in Ross patients (9.4 years) and in the same range as mechanical AVR (12.8 years).

CONCLUSIONS

Even though the overall number of paediatric DAH patients and the follow-up time span are still limited, our data suggest that DAHs may present a promising additional option for paediatric AVR.

Impact of Valve Type (Ross vs. Mechanical) on Health-Related Quality of Life in Children and Young Adults with Surgical Aortic Valve Replacement

BACKGROUND

The impact of aortic valve replacement (AVR) type on health-related quality of life (HRQOL) in adolescents and young adults is unclear, but may vary depending on need for anticoagulation or re-intervention. We sought to determine the differences in HRQOL following AVR with either the Ross procedure or mechanical AVR in this young population.

METHODS

Patients 14-35 years old and at least 1 year post-AVR were included. HRQOL was assessed using the Short Form-36 (SF-36). Valve-specific concerns regarding anticoagulation and reoperation were also assessed. Clinical outcome data were obtained by chart review.

RESULTS

A total of 51 patients were enrolled: 24 (47%) Ross and 27 (53%) mechanical AVR. Ross patients were younger at time of AVR (16 vs. 22 years, p < 0.01) and study enrollment (23.7 vs 29.5 years, p < 0.01). Median follow-up from AVR to study enrollment was similar (5.4 years for Ross vs. 5.6 years for mechanical, p = 0.62). At last follow-up, clinical outcomes including cardiac function, functional class, and aortic valve re-intervention rates were similar between groups, although mechanical valve patients had more bleeding events (p = 0.012). SF-36 scores were generally high for the entire cohort, with no significant difference between groups in any domain. Mechanical AVR patients reported more concern about frequency of blood draws (p < 0.01). Concern for reoperation was similar between both groups.

CONCLUSION

Despite more bleeding events and concern about the frequency of blood draws, adolescents and young adults with mechanical AVR reported similarly high levels of HRQOL compared to those following Ross AVR.

Longitudinal Changes in Exercise Capacity in Patients Who Underwent Ross Procedure and Mechanical Aortic Valve Replacement: Does the Type of Surgery Matter?

The surgical options for significant aortic valve disease include either Ross procedure (RP) or aortic valve replacement (AVR). The exercise stress test is routinely performed in these patients to assess the objective functional capacity. This retrospective study was conducted to evaluate the differences and the longitudinal changes of exercise capacity in patients following the RP and AVR for aortic valve disease. This is an IRB approved retrospective study and included patients who had either RP or AVR performed for aortic valve disease and had at least one exercise stress test performed after the surgical procedure. Patients with other congenital heart disease, pacemaker or defibrillators, and those with inadequate data were excluded. Demographic data including age at surgery, type of surgery and type of aortic valve was collected. Data regarding treadmill cardiopulmonary exercise test (CPET) was also collected. A total of 47 patients met inclusion criteria and were equally represented in each group, i.e. RP [n = 23, 73.9% male, age at surgery 11.2 (4.5-15.9) years] vs. AVR [n = 24, 88% mechanical AVR, 60.9% male, age at surgery 15.1 (12.8-19.4) years]. There was a significant decline in predicted oxygen consumption (%VO₂) at time of first post-operative CPET in patients after AVR compared to RP (79 vs. 88%, p = 0.048) over a similar accrued median interval follow-up (4.6 vs. 6.2 years, p = 0.2). The longitudinal follow-up analysis of following AVR (n = 11, 54.5% male, median inter-test duration of 5 years) showed significant decline in peak exercise capacity or VO₂ (34.2 vs. 26.2 vs., p = 0.006). In contrast, after RP (n = 12 patients [58.3% male, median inter-test duration 7.1 of years], exercise capacity and other key parameters remained preserved. In this small sentinel study, we report a better initial exercise capacity among patients after RP compared to AVR over an intermediate follow-up. During longitudinal follow-up in a subset of patients, exercise capacity remained preserved amongst the RP group while it further declined in the AVR group.

Mid-term durability of polytetrafluoroethylene patches in unicuspid aortic valve repair

OBJECTIVES

Unicuspid aortic valve (UAV) morphology is a cause for aortic valve dysfunction in childhood or adolescence. Repair requires the use of patch material, and polytetrafluoroethylene (PTFE) has been proposed for this purpose because of lack of calcification. We reviewed our mid-term experience with PTFE for the repair of UAV to analyse the durability of this technique.

METHODS

Out of 21 patients with an UAV undergoing aortic valve repair for severe aortic regurgitation between 2014 and 2016, 11 patients (52%) were treated using PTFE patch material. Aortic regurgitation was present in all patients, the primary indication for surgery was regurgitation in 8, stenosis in 2 and aneurysm in 1. Symmetric bicuspidization of the UAV was performed in all. One patient required additional root remodelling for root dilatation, and another 3 tubular ascending aortic replacement.

RESULTS

No patient died in hospital or during follow-up. Seven patients (63.6%) required reoperation for progressive AR. Freedom from reoperation was 58% at 1 and 35% at 5 years postoperatively. At reoperation the PTFE patches were found dehisced from aortic wall and/or native cusp tissue. In 3 patients re-repair was performed; a stable result was achieved in 1. Two patients underwent valve replacement 3 months and 1 year postoperatively. The other 4 patients underwent valve replacement.

CONCLUSIONS

The repair of UAVs using PTFE patch is associated with poor durability, a more durable patch with better healing characteristics material is needed.

[Prosthetic repair of aortic valve cusps with autopericardium in children. State of the art and prospects]

According to the results of modern researchers, the main techniques used in congenital pathology of the aortic valve in children include balloon catheter dilatation of the aortic valve, surgical valvuloplasty, the Ross procedure and replacement of the aortic valve with a mechanical prosthesis. Many surgeons point out that these techniques in congenital pathology of the aortic valve yield suboptimal results. This is often due to the lack of a clear-cut definition between surgeons as to what operation should be performed in a particular age group. According to the reports of the majority of researchers, biological prostheses undergo early degeneration and structural changes in paediatric cardiac surgery and yield the worst results. Comparing the main techniques, optimal haemodynamics is observed after the Ross procedure. A disadvantage of this operation is the necessity of repeat intervention on the right ventricular outflow tract, which is required in 20 to 40%. Concomitant surgery of the mitral valve and/or aortic arch during the Ross procedure significantly increases the lethality and the risk of postoperative complications. Compared with an adult cohort of patients, children after prosthetic repair of the aortic valve using a mechanical prosthesis are more often found to have postoperative complications and a higher mortality rate. Yet another problem encountered in paediatric valve surgery is the unavailability of commercial prostheses sized ?19 mm. The duration of the intraoperative parameters for reconstructions of the aortic valve, the Ross procedure, and replacement of the aortic valve by the results of many studies averagely amounts to 74±34 min, 100±56 min, and 129±71 min, respectively. Yet another method which can be used for neocuspidization of the aortic valve in reconstructive surgery of the aortic root in paediatric patients is the use of glutaraldehyde-treated autologous pericardium. In our opinion, given the simplicity of the procedure, duration of the intraoperative parameters, and acceptable initial results reported by some researchers, the Ozaki procedure may be performed in children.

Technical Modifications that Might Improve Long-Term Outcome of the Ross Procedure in Children

BACKGROUND

Failure of the pulmonary autograft (PVA) following the Ross procedure (RP) has discouraged its widespread use and led to modifications or alternatives to the procedure. We sought to analyze whether certain technical modifications could improve results of the RP in children.

METHODS

Sixty-nine patients (median age 12 years, range 0.25 to 17.9) underwent the RP between 01/1996 and 12/2018. Concomitant Konno procedure was performed on 20/69 (29%). Prior interventions included balloon valvuloplasty in 30/69 (44%), and/or surgical valvuloplasty in 39/69 (57%). Technical modifications included utilizing the native aortic root for external annuloplasty, implanting the autograft using uniplanar horizontal sutures through the aortic wall, normalizing the sinotubular junction and wrapping the native root remnant around the PVA.

RESULTS

Operative mortality was 1/69 (1.5%), with no late death. No patient had neoaortic valvar stenosis and 7/68 (10%) had mild regurgitation on discharge echocardiogram. At latest follow-up (median 9.4 years, range 0.4 - 21.3) there was no significant change in the latest follow up Z scores of annulus, sinus or sinotubular junction diameters when compared to those at discharge. Three patients (4.4%) required late autograft replacement, two PVA repair, and two resection of pseudoaneurysm. Actuarial freedom from PVA replacement was 87% at 20 yrs. Freedom from right ventricular outflow tract catheter reintervention or reoperation was 83% and 80% respectively.

CONCLUSIONS

Technical modifications of the RP used in this cohort might successfully prolong the life of the PVA without compromising its growth, an important advantage in pediatric patients.

Hemodynamic Profiles Before and After Surgery in Bicuspid Aortic Valve Disease-A Systematic Review of the Literature

Bicuspid aortic valve (BAV) disease presents a unique management challenge both pre- and post-operatively. 4D flow MRI offers multiple tools for the assessment of the thoracic aorta in aortic valve disease. In particular, its assessment of flow patterns and wall shear stress have led to new understandings around the mechanisms of aneurysm development in BAV disease. Novel parameters have now been developed that have the potential to predict pathological aortic dilatation and may help to risk stratify BAV patients in future. This systematic review analyses the current 4D flow MRI literature after aortic valve and/or ascending aortic replacement in bicuspid aortic valve disease. 4D flow MRI has also identified distinct challenges posed by this cohort at the time of valve replacement compared to standard management of tri-leaflet disorders, and may help tailor the type and timing of replacement. Eccentric pathological flow patterns seen after bioprosthetic valve implantation, but not with mechanical prostheses, might be an important future consideration in intervention planning. 4D flow MRI also has promising potential in supporting the development of artificial valve prostheses and aortic conduits with more physiological flow patterns.

Decellularized xenografts in regenerative medicine: From processing to clinical application

Decellularized xenografts are an inherent component of regenerative medicine. Their preserved structure, mechanical integrity and biofunctional composition have well established them in reparative medicine for a diverse range of clinical indications. Nonetheless, their performance is highly influenced by their source (ie species, age, tissue) and processing (ie decellularization, crosslinking, sterilization and preservation), which govern their final characteristics and determine their success or failure for a specific clinical target. In this review, we provide an overview of the different sources and processing methods used in decellularized xenografts fabrication and discuss their effect on the clinical performance of commercially available decellularized xenografts.

Blood flow characteristics after aortic valve neocuspidization in paediatric patients: a comparison with the Ross procedure

Aims

The aortic valve (AV) neocuspidization (Ozaki procedure) is a novel surgical technique for AV disease that preserves the natural motion and cardiodynamics of the aortic root. In this study, we sought to evaluate, by 4D-flow magnetic resonance imaging, the aortic blood flow characteristics after AV neocuspidization in paediatric patients.

Methods and results

Aortic root and ascending aorta haemodynamics were evaluated in a population of patients treated with the Ozaki procedure; results were compared with those of a group of patients operated with the Ross technique. Cardiovascular magnetic resonance studies were performed at 1.5 T using a 4D flow-sensitive sequence acquired with retrospective electrocardiogram-gating and respiratory navigator. Post-processing of 4D-flow analysis was performed to calculate flow eccentricity and wall shear stress. Twenty children were included in this study, 10 after Ozaki and 10 after Ross procedure. Median age at surgery was 10.7 years (range 3.9–16.5 years). No significant differences were observed in wall shear stress values measured at the level of the proximal ascending aorta between the two groups. The analysis of flow patterns showed no clear association between eccentric flow and the procedure performed. The Ozaki group showed just a slightly increased transvalvular maximum velocity.

Conclusion

Proximal aorta flow dynamics of children treated with the Ozaki and the Ross procedure are comparable. Similarly to the Ross, Ozaki technique restores a physiological laminar flow pattern in the short-term follow-up, with the advantage of not inducing a bivalvular disease, although further studies are warranted to evaluate its long-term results.

The Commando procedure: Can it be a preventive option from reoperation in pediatric patients?

Rheumatic heart disease is still an important pathology affecting young people. When valve repair techniques are not possible, valve replacement is inevitable in pediatric patients despite the risk of patient prosthesis mismatch with the growing child. In this report, we present aortomitral fibrous body remodeling, Commando procedure, in a 12-year-old male patient with rheumatic aortic and mitral valve disease to provide adult size mechanical double valve replacement.

Aortic valve surgery: management and outcomes in the paediatric population

Congenital anomalies of the aortic valve frequently necessitate intervention in childhood. The most common aortic valve pathologies present in childhood are aortic stenosis and insufficiency. Presentation of aortic valve disease depends on severity and presence of concomitant syndromes and valvular disorders. Treatment options are largely categorised as medical, percutaneous repair or surgical repair and replacement. Surgical techniques have been refined over the last few years making this the mainstay of treatment in paediatric cases. Whilst repair is considered in most instances before replacement, there are substantial limitations which are reflected in the frequency of reintervention and restenosis rate. Replacements are typically undertaken with tissue or mechanical prosthesis. The current gold-standard aortic valve replacement surgery is called the Ross procedure-where replacement is undertaken with a competent pulmonic valve and a simultaneous pulmonary homograft.Conclusion: In this review, we aim to outline the various surgical options and discuss efficacy and complications of various interventions. What is Known: • Congenital aortic valve defects repair options medically and surgically What is New: • Comparisons between surgical options for aortic valve repair including efficacy, risks and long-term outcomes.

Aortic Valve Neocuspidalization May Be a Viable Alternative to Ross Operation in Pediatric Patients

The aim of the study was to evaluate the medium-term results of aortic valve neocuspidalization according to Ozaki compared to Ross procedure for treatment of isolated aortic valve disease in pediatric age. Thirty-eight consecutive patients with congenital or acquired aortic valve disease underwent either Ozaki (n = 22) or Ross (n = 16) operation between 01/2015 and 05/2020. The primary outcome was progression of aortic valve disease and aortic ring and root dimension, whereas secondary outcome was freedom from reintervention or death by type of operation. Median age was 12.4 (8.8-15.8) years and the prevailing lesion was stenosis in 20 cases (52%) and incompetence in 18 (48%). One death occurred in the Ross group in the early postoperative period, while there were no deaths in the Ozaki group. Effective treatment of aortic valve stenosis or regurgitation occurred in both groups and remained stable over a median follow-up of 18.2 (5-32) months. In Ozaki group, 3 patients required aortic valve replacement at 4.9, 3.5, and 33 months, respectively. In Ross group, 1 patient required Melody pulmonary valve replacement, whereas none required aortic valve surgery. Finally, significantly higher aortic transvalvular gradient at follow-up was recorded in Ozaki group compared to Ross group. Overall, there was no significant difference in freedom from reoperation or death between the two groups. The medium-term outcome of Ozaki and Ross in pediatric patients is similar, despite an increased tendency of the former to develop aortic transvalvular gradient in the follow-up. Future larger multicenter studies with longer follow-up are warranted to confirm these results.

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.

Next-generation tissue-engineered heart valves with repair, remodelling and regeneration capacity

Valvular heart disease is a major cause of morbidity and mortality worldwide. Surgical valve repair or replacement has been the standard of care for patients with valvular heart disease for many decades, but transcatheter heart valve therapy has revolutionized the field in the past 15 years. However, despite the tremendous technical evolution of transcatheter heart valves, to date, the clinically available heart valve prostheses for surgical and transcatheter replacement have considerable limitations. The design of next-generation tissue-engineered heart valves (TEHVs) with repair, remodelling and regenerative capacity can address these limitations, and TEHVs could become a promising therapeutic alternative for patients with valvular disease. In this Review, we present a comprehensive overview of current clinically adopted heart valve replacement options, with a focus on transcatheter prostheses. We discuss the various concepts of heart valve tissue engineering underlying the design of next-generation TEHVs, focusing on off-the-shelf technologies. We also summarize the latest preclinical and clinical evidence for the use of these TEHVs and describe the current scientific, regulatory and clinical challenges associated with the safe and broad clinical translation of this technology.