Aortic valve surgery in children

Survival after partial heart transplantation in a piglet model

Partial heart transplantation (PHT) is a novel surgical approach that involves transplantation of only the part of the heart containing a valve. The rationale for this approach is to deliver growing heart valve implants that reduce the need for future re-operations in children. However, prior to clinical application of this approach, it was important to assess it in a preclinical model. To investigate PHT short-term outcomes and safety, we performed PHT in a piglet model. Yorkshire piglets (n = 14) were used for PHT of the pulmonary valve. Donor and recipient pairs were matched based on blood types. The piglets underwent PHT at an average age of 44 days (range 34-53). Post-operatively, the piglets were monitored for a period of two months. Of the 7 recipient piglets, one mortality occurred secondary to anesthesia complications while undergoing a routine echocardiogram on post-operative day 19. All piglets had appropriate weight gain and laboratory findings throughout the post-operative period indicating a general state of good health and rehabilitation after undergoing PHT. We conclude that PHT has good short-term survival in the swine model. PHT appears to be safe for clinical application.

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.

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.

Surgery for paravalvular abscess in children

Objective

To investigate the outcomes of surgery in children with paravalvular abscess at our institution.

Methods

A retrospective review of all patients who underwent surgery for paravalvular abscess was performed.

Results

Between 1989 and 2020, 30 patients underwent surgery for paravalvular abscess, of whom 5 (16.7%) had an intracardiac fistula and 6 (20.0%) had a pseudoaneurysm. Aortic annulus abscesses were most common, occurring in 23 patients (76.7%). Aortic root replacement was performed in 17 patients (56.7%), root reconstruction was performed in 4 (13.3%), and reconstruction of the central fibrous body was required in 5 (16.7%). Postoperatively, 7 patients (23.3%) required extracorporeal membrane oxygenation (ECMO) support, and 1 patient (3.3%) required permanent pacemaker insertion. There were 6 early deaths, 5 of whom were on ECMO, and no late deaths, with a 15-year survival of 79.7% (95% confidence interval [CI], 60.2%-90.3%). Deaths were from sudden cardiac arrest resulting in brain death in 3 patients, inability to wean from ECMO due to severe cardiac dysfunction in 2 patients, and cerebral mycotic aneurysm and hemorrhage in 1 patient. Freedom from reoperation was 40.0% (95% CI, 17.0%-62.3%) at 15 years Reoperation due to recurrence was rare, occurring in only 2 patients (6.7%). Streptococcus pneumoniae (hazard ratio [HR], 9.2; 95% CI, 1.6-51.7) and preoperative shock (HR, 6.4; 95% CI, 1.3-32.0) were associated with mortality. Central fibrous body reconstruction was associated with reoperation (HR, 4.4; 95% CI, 1.2-16.1).

Conclusions

Although paravalvular abscess in children is associated with high early mortality, hospital survivors have good long-term survival. Reoperation is frequent, but is rarely due to recurrence of endocarditis.

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.

Trends in pediatric donor heart discard rates and the potential use of unallocated hearts for allogeneic valve transplantation

Objectives

Allogeneic valve transplantation is an emerging therapy that delivers a living valve from a donor heart. We reviewed the national discard rate of pediatric and young adult (aged 25 years or younger) donor grafts to estimate the number of hearts potentially available to source valve allotransplantation.

Methods

We queried the United Network for Organ Sharing database to identify pediatric and young adult heart donors from 1987 to 2022. Donor heart discard was defined as nontransplantation of the allograft.

Results

Of 72,460 pediatric/young adult heart donations, 41,065 (56.7%) were transplanted and 31,395 (43.3%) were unutilized. The average annual number of discarded hearts in era 1 (1987-2000), era 2 (2000-2010), and era 3 (2010-2022) was 791 (42.8%), 1035 (46.3%), and 843 (41.2%), respectively. From 2017 to 2021, the average annual number of discards by age was: 39 (31.8%) neonates/infants, 78 (38.0%) toddlers, 41 (49.4%) young children, 240 (38.0%) adolescents, and 498 (40.1%) young adults. High-volume procurement regions had the greatest proportion of nonutilization, with the national average discard rate ranging from 39% to 49%. The most frequently documented reasons for nonallocation were distribution to the heart valve industry (26.5%), presumably due to suboptimal graft function, poor organ function (22.7%), and logistical challenges (10.8%).

Conclusions

With ∼900 pediatric/young adult donor hearts discarded annually, unutilized grafts represent a potential source of valves for allogeneic valve transplant to supplement current conduit and valve replacement surgery. The limited availability of neonatal and infant hearts may limit this technique in the youngest patients, for whom cryopreserved homografts or xenografts will likely remain the primary valve substitute.

Urgent aortic valve neocuspidization using the Ozaki procedure in an infant with native aortic valve endocarditis

Native valve aortic endocarditis is rarely seen in the paediatric population. Although, the first-line of treatment is medical, surgical intervention may be indicated in patients with unrepairable valvular and subvalvular disease. Recently, the aortic valve neocuspidization (AVNeo) procedure has gained popularity both in adult and children in whom other repair techniques are not feasible. In this case report, we present an urgent aortic valve replacement using the AVNeo technique in a critically ill infant with a small annulus, severe left ventricular outflow tract stenosis, and severe aortic regurgitation.

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.

Long-term outcomes of primary aortic valve repair in children with congenital aortic stenosis - 15-year experience at a single center

Background

Studies on the long-term outcomes of children with congenital aortic stenosis who underwent primary aortic repair are limited. We reviewed the long-term outcomes of children who underwent aortic valve (AoV) repair at our center.

Methods

All children (n = 75) who underwent AoV repair between 2006 and 2020 were reviewed. The Kaplan-Meier curve was used to demonstrate the survival estimates. The Cox proportional hazard model and competing risk regression model were used to identify risk factors for death, reintervention, adverse events, and replacement.

Results

The median age at surgery was 1.8 (IQR, 0.2–7.7) years, and the median weight at surgery was 10.0 (IQR, 5.0–24.0) kg. Early mortality and late mortality were 5.3% (4/75) and 5.6% (4/71), respectively. Risk factors for overall mortality were concomitant mitral stenosis (P = 0.01, HR: 9.8, 95% CI: 1.8–53.9), low AoV annulus Z-score (P = 0.01, HR: 0.6, 95% CI: 0.4–0.9), and prolonged cardiopulmonary bypass time (P < 0.01, HR: 9.5, 95% CI: 1.7–52.1). Freedom from reintervention was 72.9 ± 0.10% (95% CI: 56.3–94.4%) at 10 years. Risk factors for occurrence of adverse event on multivariable analysis included preoperative intubation (P = 0.016, HR: 1.004, 95% CI: 1.001–1.007) and a low AoV annulus Z-score (P = 0.019, HR: 0.714, 95% CI: 0.540–0.945). Tricuspid AoV morphology was associated with a suboptimal postoperative outcome (P = 0.03).

Conclusion

Aortic valve repair remains a safe and durable solution for children with congenital aortic stenosis. Concomitant mitral stenosis and aortic valve anatomy, including tricuspid valve morphology and smaller annulus size, are associated with poor early and long-term outcomes.

Aortic Valve Repair in Neonates With Aortic Stenosis and Reduced Left Ventricular Function

This study assessed outcomes of neonatal aortic valve (AoV) repair in presumed high-risk patients with depressed left ventricular (LV) function. A retrospective analysis of all neonates who underwent isolated AoV repair for severe aortic stenosis (AS) was performed. Patients with moderate or severe LV dysfunction were compared to those with normal or mild LV dysfunction. From 1980-2021, 43 neonates underwent isolated AoV repair for AS. Of these, 16 patients (37.2%) had ≥moderate LV dysfunction. Mean LV ejection fraction (EF) was 32.8 ± 9.1%. Valve morphology was mostly unicuspid (68.75%, 11/16). Median age at surgery was 6.5 days (IQR 1-17.5). An optimal repair result with ≤mild AS or aortic regurgitation was achieved in 75% (12/16). There was no early death. One patient (6.25%) required postoperative extracorporeal membrane oxygenation (ECMO) support for 3 days. LVEF improved after surgery to 56.4 ± 12.6% before discharge (P < 0.0001) and normalized in 87.5% (14/16) with a median time of 6.4 days (IQR 3.4-39). Freedom from AoV reoperation was 45.1% (95%CI 17.9-69.3%) and 27.1% (95%CI 6.8-53%) at 5 and 10 years, respectively. Freedom from AoV replacement was 59% (95%CI 27-80.8%) and 31.4% (95%CI 6-62.2%) at 5 and 10 years, respectively. While survival was similar, freedom from AoV reoperation and replacement tended to be lower compared to neonates with preserved LVEF. AoV repair was associated with a low incidence of postoperative ECMO and mortality. LV function normalized after relief of obstruction in most patients before discharge. Late reoperation remained common for those with severely dysplastic valves.

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.

Ross Procedure in the era of Handmade-Valved Conduits for Right Ventricular Outflow Tract Reconstruction in Children: Short-Term Surgical Outcomes

Objective

Ross procedure is considered as the “gold standard” for aortic valve replacement, but the conduits used for right ventricular outflow tract (RVOT) reconstruction, such as homografts and bovine jugular vein (BJV) conduits, are of limited availability in China. Handmade expanded polytetrafluoroethylene-valved conduits (HVCs) have been used recently as the alternative for RVOT reconstruction, but their specific experience in Ross procedure is limited in the literature.

Methods

This was a retrospective review of 27 children who underwent Ross procedure in our center from January 2018 to January 2022.

Results

Mean age at surgery was 8.0 ± 3.8 years. During the study period, BJV conduits were used for RVOT reconstruction in 6 patients (22%), and HVCs were used in 21 patients (78%). Median conduit size was 20 mm (range, 16–24 mm), and mean conduit Z-score was +0.8 ± 0.9. Median time for cardiopulmonary bypass was 158 min (range, 109–275 min), and mean time for aortic crossclamping was 110 ± 21 min. There was no early mortality. During a median follow-up time of 1.4 years (range, 0.1–3.7 years), 3 patients (11%) with BJV conduits had peak conduit velocity of &gt; 3.5 m/s; 3 patients (11%) with HVCs developed moderate conduit insufficiency; no patients had more than moderate conduit insufficiency. Three patients with BJV conduits had 5 reinterventions, and all received conduit replacement with HVCs.

Conclusion

HVC is an appealing alternative to BJV conduit for RVOT construction for children undergoing Ross procedure, with favorable short-term outcomes.

Single leaflet reconstruction in paediatric aortic regurgitation using the Ozaki procedure

OBJECTIVES

Aortic valve repair in children is still a challenge. The aim of this study was to analyse the surgical results of children with aortic regurgitation who underwent single leaflet reconstruction using the Ozaki procedure in our medical centre.

METHODS

A retrospective study was conducted of nine children with aortic regurgitation who received single leaflet reconstruction from May 2017 to September 2019. Paired t-tests and Wilcoxon signed rank tests were used to compare the data at different time points.

RESULTS

The median surgical age was 4.7 (3.5, 6.4) years. Eight patients were pre-operatively diagnosed with severe aortic regurgitation, while one had moderate regurgitation. The left ventricles were significantly enlarged, with an average z-score of 3.8. Single leaflet reconstruction was carried out using glutaraldehyde-treated autologous pericardium under the standard Ozaki procedure. The median follow-up was 22 (14, 33) months. There was no post-operative death or re-intervention. One patient had moderate or more aortic regurgitation during the follow-up. The average degree of aortic regurgitation was mild, and the average z-score of the left ventricle decreased to -0.2 in the last follow-up.

CONCLUSIONS

Single leaflet reconstruction using the Ozaki procedure was an effective surgical method for treating children with aortic regurgitation in our centre with satisfactory short-term results.

Complex Repair of a Completely Fused Nullicuspid Aortic Valve Late in Adolescence

We report a case of an 18-year-old female who presented with severe aortic stenosis and insufficiency, eight years following resection of a subaortic membrane. On echocardiography, she was found to have a completely fused or nullicuspid valve, with three equal sinuses and three commissural fusions. Aortic valve repair included leaflet tricuspidization, three commissurotomies, trileaflet ring annuloplasty, and pericardial leaflet reconstruction. At one year follow-up, the patient is asymptomatic, with stable gradients.