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.

Growing Heart Valve Implants for Children

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

Partial Heart Transplantation in Adult Cardiac Surgery

Many young adults require heart valve replacements. Current options for valve replacement in adults include mechanical valves, bioprosthetic valves, or the Ross procedure. Of these, mechanical and bioprosthetic valves are the most common options, although mechanical valve usage predominates in younger adults due to durability, while bioprosthetic valve usage predominates in older adults. Partial heart transplantation is a new method of valvular replacement that can deliver durable and self-repairing valves and allow adult patients freedom from anticoagulation therapy. This procedure involves transplantation of donor heart valves only, permitting expanded utilization of donor hearts as compared with orthotopic heart transplantation. In this review, we discuss the potential benefits of this procedure in adults who elect against the anticoagulation regimen required of mechanical valve replacements, although it has not yet been clinically established. Partial heart transplantation is a promising new therapy for the treatment of pediatric valvular dysfunction. This is a novel technique in the adult population with potential utility for valve replacement in young patients for whom anticoagulation therapy is problematic, such as women who wish to become pregnant, patients with bleeding disorders, and patients with active lifestyles.

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

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

Whole-Chest Three-Dimensional Modeling Aids Hybrid Pulmonary Valve Replacement Following Double Switch Operation

The double switch operation for congenitally corrected transposition of the great arteries (CC-TGA) has been associated with high rates of reintervention, including the need for pulmonary valve replacement. Hybrid interventional approaches can avoid bypass when complex anatomy complicates traditional catheter-based approaches. We present a case of successful transcatheter pulmonary valve replacement via hybrid per-ventricular approach with pre-procedural planning aided by 3D segmentation of skeletal and cardiac anatomy in a patient with surgically corrected CC-GTA.

Sustained Total All-Region Perfusion During the Norwood Operation and Postoperative Recovery

We developed a technique for the Norwood operation utilizing continuous perfusion of the head, heart, and lower body at mild hypothermia named Sustained Total All-Region (STAR) perfusion. We hypothesized that STAR perfusion would be associated with shorter operative times, decreased coagulopathy, and expedited post-operative recovery compared to standard perfusion techniques. Between 2012 and 2020, 80 infants underwent primary Norwood reconstruction at our institution. Outcomes for patients who received successful STAR perfusion (STAR, n = 37) were compared to those who received standard Norwood reconstruction utilizing regional cerebral perfusion only (SNR, n = 33), as well as to Norwood patients reported in the PC⁴ national database during the same timeframe (n = 1238). STAR perfusion was performed with cannulation of the innominate artery, descending aorta, and aortic root at 32-34°C. STAR patients had shorter median CPB time compared to SNR (171 vs 245 minutes, P < 0.0001), shorter operative time (331 vs 502 minutes, P < 0.0001), and decreased intraoperative pRBC transfusion (100 vs 270 mL, P < 0.0001). STAR patients had decreased vasoactive-inotropic score on ICU admission (6 vs 10.8, P = 0.0007) and decreased time to chest closure (2 vs 4.5 days, P = 0.0004). STAR patients had lower peak lactate (8.1 vs 9.9 mmol/L, P = 0.03) and more rapid lactate normalization (18.3 vs 27.0 hours, P = 0.003). In-hospital mortality in STAR patients was 2.7% vs 15.1% with SNR (P = 0.06) and 10.3% in the PC⁴ aggregate (P = 0.14). STAR perfusion is a novel approach to Norwood reconstruction associated with excellent survival, decreased transfusions, shorter operative time, and improved convalescence in the early post-operative period.

Methylprednisolone for Heart Surgery in Infants - A Randomized, Controlled Trial

BACKGROUND

Although perioperative prophylactic glucocorticoids have been used for decades, whether they improve outcomes in infants after heart surgery with cardiopulmonary bypass is unknown.

METHODS

We conducted a multicenter, prospective, randomized, placebo-controlled, registry-based trial involving infants (<1 year of age) undergoing heart surgery with cardiopulmonary bypass at 24 sites participating in the Society of Thoracic Surgeons Congenital Heart Surgery Database. Registry data were used in the evaluation of outcomes. The infants were randomly assigned to receive prophylactic methylprednisolone (30 mg per kilogram of body weight) or placebo, which was administered into the cardiopulmonary-bypass pump-priming fluid. The primary end point was a ranked composite of death, heart transplantation, or any of 13 major complications. Patients without any of these events were assigned a ranked outcome based on postoperative length of stay. In the primary analysis, the ranked outcomes were compared between the trial groups with the use of odds ratios adjusted for prespecified risk factors. Secondary analyses included an unadjusted odds ratio, a win ratio, and safety outcomes.

RESULTS

A total of 1263 infants underwent randomization, of whom 1200 received either methylprednisolone (599 infants) or placebo (601 infants). The likelihood of a worse outcome did not differ significantly between the methylprednisolone group and the placebo group (adjusted odds ratio, 0.86; 95% confidence interval [CI], 0.71 to 1.05; P = 0.14). Secondary analyses (unadjusted for risk factors) showed an odds ratio for a worse outcome of 0.82 (95% CI, 0.67 to 1.00) and a win ratio of 1.15 (95% CI, 1.00 to 1.32) in the methylprednisolone group as compared with the placebo group, findings suggestive of a benefit with methylprednisolone; however, patients in the methylprednisolone group were more likely than those in the placebo group to receive postoperative insulin for hyperglycemia (19.0% vs. 6.7%, P<0.001).

CONCLUSIONS

Among infants undergoing surgery with cardiopulmonary bypass, prophylactic use of methylprednisolone did not significantly reduce the likelihood of a worse outcome in an adjusted analysis and was associated with postoperative development of hyperglycemia warranting insulin in a higher percentage of infants than placebo. (Funded by the National Center for Advancing Translational Sciences and others; STRESS ClinicalTrials.gov number, NCT03229538.).

Partial heart transplantation can ameliorate donor organ utilization

BACKGROUND

The treatment of babies with unrepairable heart valve dysfunction remains an unsolved problem because there are no growing heart valve implants. However, orthotopic heart transplants are known to grow with recipients.

AIM

Partial heart transplantation is a new approach to delivering growing heart valve implants, which involves transplantation of the part of the heart containing the valves only. In this review, we discuss the benefits of this procedure in children with unrepairable valve dysfunction.

CONCLUSION

Partial heart transplantation can be performed using donor hearts with poor ventricular function and slow progression to donation after cardiac death. This should ameliorate donor heart utilization and avoid both primary orthotopic heart transplantation in children with unrepairable heart valve dysfunction and progression of these children to end-stage heart failure.

Toward improved understanding of cardiac development and congenital heart disease: The advent of cardiac organoids

Human cardiac organoid systems hold significant promise for mechanistic studies of early heart morphogenesis and an improved understanding of congenital cardiac disease.

During the past decade, we have witnessed remarkable progress in genome editing technology, stem cell research, and bioengineering. The fundamental basic research discoveries accelerate rapidly into clinical translation, paving the way for myocardial regeneration, better understanding of the structural heart disease, and bioengineering of heart structures and even entire hearts. The new horizon is vast and diverse, ranging from creating universal stem cell biobanking to genome edited heart xenotransplantation. Herein, a group of experts from Duke University discuss the state of the art and the possible influence of cardiac organoids on our understanding of structural heart disease. It may not be immediately clear now in what practical ways this technology will be translated into our daily work, yet the current progress in bioengineering will likely have a very significant influence on our surgical practice.

Igor E. Konstantinov, MD, PhD, FRACS

Recent advances in porcine cardiac xenotransplantation: from aortic valve replacement to heart transplantation

INTRODUCTION

Cardiac xenotransplantation presents significant potential to the field of heart failure by addressing the high demand for donor organs. The availability of xenograft hearts would substantially augment the number of life-saving organs available to patients and may ultimately liberalize eligibility criteria for transplantation.

AREAS COVERED

In this review, we will discuss the need for cardiac xenotransplantation and the history of research and clinical practice in this field. Specifically, we address immunologic concepts and clinical lessons learned from heart valve replacement using xenogeneic tissues, the advancement of xenotransplantation using organs from genetically modified animals, and the progression of this research to the first-in-man pig-to-human heart transplantation.

EXPERT OPINION

Cardiac xenotransplantation holds tremendous promise, but the indications for this new treatment will need to be clearly defined because mechanical support with ventricular assist devices and total artificial hearts are increasingly successful alternatives for adults in heart failure. Cardiac xenotransplantation will also serve as temporary bridge to allotransplantation in babies with complex congenital heart disease who are too small for the currently available mechanical assist devices. Moreover, xenotransplantation of the part of the heart containing a heart valve could deliver growing heart valve implants for babies with severe heart valve dysfunction.

Minimally Invasive Approach for Cardiac Hemangioma Resection in a Teenager

Cardiac hemangiomas are a rare tumor traditionally resected by median sternotomy. We performed a minimally invasive right ventricular cardiac hemangioma resection via a left anterior mini-incision (LAMI). The procedure was without complication, and the patient was discharged on postoperative day 2. The LAMI has been used broadly by our team for operations involving the right ventricular outflow tract, as an alternative to median sternotomy. Here we show that it can also be used for the resection of a cardiac tumor.

Introducing thymus for promoting transplantation tolerance

Establishing tolerance remains a central, if elusive, goal of transplantation. In solid-organ transplantation, one strategy for inducing tolerance has been cotransplantation of various forms of thymic tissue along with another organ. As one of the biological foundations of central tolerance, thymic tissue carries with it the ability to induce tolerance to any other organ or tissue from the same donor (or another donor tissue-matched to the thymic tissue) if successfully transplanted. In this review, we outline the history of this approach as well as work to date on its application in organ transplantation, concluding with future directions. We also review our experience with allogeneic processed thymus tissue for the treatment of congenital athymia, encompassing complete DiGeorge syndrome and other rare genetic disorders, and consider whether allogeneic processed thymic tissue implantation may offer a novel method for future experimentation with tolerance induction in organ transplantation.

Early Outcomes of Patients Undergoing Neoaortic Valve Repair Incorporating Geometric Ring Annuloplasty

OBJECTIVES

During congenital heart surgery, the pulmonary valve and root may be placed into the systemic position, yielding a "neoaortic" valve. With the stress of systemic pressure, the pulmonary roots can dilate, creating aneurysms and/or neoaortic insufficiency (neoAI). This report analyzes the early outcomes of patients undergoing neoaortic valve repair incorporating geometric ring annuloplasty.

METHODS

Twenty-one patients underwent intended repair at six centers and formed the study cohort. Thirteen had previous Ross procedures, five had arterial switch operations, and three Fontan physiology. Average age was 21.7 ± 12.8 years (mean  ±  SD), 80% were male, and 11 (55%) had symptomatic heart failure. Preoperative neoAI Grade was 3.1  ±  1.1, and annular diameter was 30.7  ±  6.5 mm.

RESULTS

Valve repair was accomplished in 20/21, using geometric annuloplasty rings and leaflet plication (n = 13) and/or nodular release (n = 7). Fourteen had neoaortic aneurysm replacement (13 with root remodeling). Two underwent bicuspid valve repair. Six had pulmonary conduit changes, one insertion of an artificial Nodulus Arantius, and one resection of a subaortic membrane. Ring size averaged 21.9  ±  2.3 mm, and aortic clamp time was 171  ±  54 minutes. No operative mortality or major morbidity occurred, and postoperative hospitalization was 4.3  ±  1.4 days. At discharge, neoAI grade was 0.2  ±  0.4 (P < .0001), and valve mean gradient was ≤20 mm Hg. At average 18.0  ±  9.1 months of follow-up, all patients were asymptomatic with stable valve function.

CONCLUSIONS

Neoaortic aneurysms and neoAI are occasionally seen late following Ross, arterial switch, or Fontan procedures. Neoaortic valve repair using geometric ring annuloplasty, leaflet reconstruction, and root remodeling provides a patient-specific approach with favorable early outcomes.

Biventricular Conversion of Borderline Hypoplastic Left Heart Complex Facilitated by Spontaneous Closure of the Atrial Septum

We present the case of a child with borderline hypoplastic left heart complex who initially received Norwood and Glenn operations without atrial septectomy and was later converted to a biventricular circulation after progressive growth of the left ventricle as assessed by serial echocardiography and cardiac magnetic resonance imaging.