Atrioventricular Valve Annular Remodeling With a Bioabsorbable Ring in Young Children

Mechanical tricuspid valve replacement in hypoplastic left heart syndrome: An institutional experience

Objective

Atrioventricular valvar regurgitation in patients with single ventricles is associated with worse outcomes. Valve repair or replacement has been undertaken in an attempt to reduce mortality and morbidity. Current data on valve replacement in single ventricle patients are limited and derived from heterogenous populations. We describe our experience with repair and replacement of the tricuspid valve in children undergoing single ventricle palliation for hypoplastic left heart syndrome.

Methods

We included 27 patients with hypoplastic left heart syndrome with at least moderate tricuspid regurgitation who underwent valve intervention between 2007 and 2021 at our institution; charts were retrospectively reviewed for data.

Results

Eleven patients (73% male) underwent valve replacement (median age, 3 years). Preoperative ventricular systolic function was normal in 10 patients (91%). Median follow-up postoperatively was 4 years with no early mortality, 1 (9%) late mortality, and 1 heart transplant (9%). Morbidity consisted of complete heart block in 1 patient (9%), with no important hemorrhagic or thrombotic events. Among survivors of replacement (n = 9), ventricular function was preserved in all (n = 8) who had normal function preoperatively and improved in the remaining patient. Sixteen patients underwent valve repair (median age, 4 months) with no early mortality, 8 (50%) midterm mortalities, and 2 heart transplants (12%).

Conclusions

Tricuspid valve replacement is a feasible option in hypoplastic left heart syndrome with significant tricuspid regurgitation, with favorable outcomes in the intermediate follow-up. When undertaken in the setting of normal function, ventricular function may be preserved in up to 80% of patients. Long-term follow-up is needed.

Expandable Valves, Annuloplasty Rings, Shunts, and Bands for Growing Children

In congenital heart surgery, the surgeon must constantly consider how a palliative or corrective procedure could be impacted by the child's somatic growth. Within pediatric valve surgery, existing valve repair techniques lack growth-accommodating prostheses. Valve replacement options are fixed in size and unable to grow with the child, thus subjecting children to repeated valve reoperations. When creating a systemic-to-pulmonary artery shunt, replacing a branch pulmonary artery or conduit, creating an extracardiac Fontan pathway, or banding the pulmonary artery, the implant size must factor in both the child's current size and his or her anticipated growth. A variety of growth-accommodating technologies have been developed to fill this unmet need. Some devices have reached the clinical arena, while several are in preclinical development. The purpose of this review is to characterize the clinical need for growing device technology, and then review established and developing technologies for growth accommodation in congenital heart surgery.

Three-Dimensional Mitral Valve Morphology in Children and Young Adults With Marfan Syndrome

BACKGROUND

Mitral valve (MV) prolapse is common in children with Marfan syndrome (MFS) and is associated with varying degrees of mitral regurgitation (MR). However, the three-dimensional (3D) morphology of the MV in children with MFS and its relation to the degree of MR are not known. The goals of this study were to describe the 3D morphology of the MV in children with MFS and to compare it to that in normal children.

METHODS

Three-dimensional transthoracic echocardiography was performed in 27 patients (3-21 years of age) meeting the revised Ghent criteria for MFS and 27 normal children matched by age (±1 year). The 3D geometry of the MV apparatus in midsystole was measured, and its association with clinical and two-dimensional echocardiographic parameters was examined.

RESULTS

Compared with age-matched control subjects, children with MFS had larger 3D annular areas (P < .02), smaller annular height/commissural width ratios (P < .001), greater billow volumes (P < .001), and smaller tenting heights, areas, and volumes (P < .001 for all). In multivariate modeling, larger leaflet billow volume in MFS was strongly associated with moderate or greater MR (P < .01). Intra- and interuser variability of 3D metrics was acceptable.

CONCLUSIONS

Children with MFS have flatter and more dilated MV annuli, greater billow volumes, and smaller tenting heights compared with normal control subjects. Larger billow volume is associated with MR. Three-dimensional MV quantification may contribute to the identification of patients with MFS and other connective tissue disorders. Further study of 3D MV geometry and its relation to the clinical progression of MV disease is warranted in this vulnerable population.

A Growth-Accommodating Implant for Paediatric Applications

Medical implants of fixed size cannot accommodate normal tissue growth in children, and often require eventual replacement or in some cases removal, leading to repeated interventions, increased complication rates and worse outcomes. Implants that can correct anatomic deformities and accommodate tissue growth remain an unmet need. Here, we report the design and use of a growth-accommodating device for paediatric applications that consists of a biodegradable core and a tubular braided sleeve, with inversely related sleeve length and diameter. The biodegradable core constrains the diameter of the sleeve, and gradual core degradation following implantation enables sleeve and overall device elongation in order to accommodate tissue growth. By using mathematical modeling and ex vivo experiments using harvested swine hearts, we demonstrate the predictability and tunability of the behavior of the device for disease- and patient-specific needs. We also used the rat tibia and the piglet heart valve as two models of tissue growth to demonstrate that polymer degradation enables device expansion and growth accommodation in vivo.

An Unusual Case of Arterial Embolism in an Adolescent With a Mitral Valve Repair With a Ring

We report a case of an adolescent young man who presented with embolism of both lower legs. The patient had undergone mitral valve repair with a Kalangos biodegradable ring (Bioring SA, Lonay, Switzerland) 9 months earlier. Bilateral embolectomy was performed. Histopathologic examination revealed minute fragments of synthetic material within the embolus, which otherwise consisted of recent thrombus.

Valve reconstruction for congenital mitral valve disease

The surgical treatment of mitral valve disease in children is a challenging problem. Mitral stenosis and regurgitation may occur in isolation or together. Mitral valve repair is almost always preferable to replacement. Mitral valve replacement is not an ideal alternative to repair due to limitations of size, growth, structural valve degeneration, anticoagulation and poor survival. Surgical repair of congenital mitral stenosis must address the multiple levels of obstruction, including resection of the supramitral ring, thinning of leaflets and mobilization of the subvalvular apparatus. Sometimes leaflet augmentation is required. Repair of mitral regurgitation in children may involve simple cleft closures, edge-to-edge repairs, triangular resections and annuloplasties. Techniques used in adults, such as annuloplasty bands or artificial chords, may not be appropriate for children. Overall, an imperfect mitral valve repair may be more acceptable than the negative consequences of a replacement in a child.

Biodegradable materials for surgical management of infective endocarditis: new solution or a dead end street?

Background

One third of patients with infective endocarditis will require operative intervention. Given the superiority of valve repair over valve replacement in many indications other than endocarditis, there has been increasing interest and an increasing number of reports of excellent results of valve repair in acute infective endocarditis. The theoretically ideal material for valve repair in this setting is non-permanent, “vanishing” material, not at risk of seeding or colonization. The goal of this contribution is to review currently available data on biodegradable materials for valve repair in infective endocarditis.

Discussion

Rigorous electronic and manual literature searches were conducted to identify reports of biodegradable materials for valve repair in infective endocarditis. Articles were identified in electronic database searches of Medline, Embase and the Cochrane Library, using a predetermined search strategy. 49 manuscripts were included in the review. Prosthetic materials needed for valve repair can be summarized into annuloplasty rings to remodel the mitral or tricuspid annulus, and patch materials to replace resected valvar tissue. The commercially available biodegradable annuloplasty ring has shown interesting clinical results in a single-center experience; however further data is required for validation and longer follow-up. Unmodified extra-cellular matrix patches, such as small intestinal submucosa, have had promising initial experimental and clinical results in non-infected valve repair, although in valve repair for endocarditis has been reported in only one patient, and concerns have been raised regarding their mechanical stability in an infected field.

Summary

These evolving biodegradable devices offer the potential for valve repair with degradable materials replaced with autologous tissue, which could further improve the results of valve repair for infective endocarditis. This is an evolving field with promising experimental or initial clinical results, however long-term outcomes are lacking and further data is necessary to validate this theoretically interesting approach to infective endocarditis.