Surgical repair of mitral valve bileaflet prolapse in pediatric patients

Euclidean and Shape-Based Analysis of the Dynamic Mitral Annulus in Children using a Novel Open-Source Framework

BACKGROUND

The dynamic shape of the normal adult mitral annulus has been shown to be important to mitral valve function. However, annular dynamics of the healthy mitral valve in children have yet to be explored. The aim of this study was to model and quantify the shape and major modes of variation of pediatric mitral valve annuli in four phases of the cardiac cycle using transthoracic echocardiography.

METHODS

The mitral valve annuli of 100 children and young adults with normal findings on three-dimensional echocardiography were modeled in four different cardiac phases using the SlicerHeart extension for 3D Slicer. Annular metrics were quantified using SlicerHeart, and optimal normalization to body surface area was explored. Mean annular shapes and the principal components of variation were computed using custom code implemented in a new SlicerHeart module (Annulus Shape Analyzer). Shape was regressed over metrics of age and body surface area, and mean shapes for five age-stratified groups were generated.

RESULTS

The ratio of annular height to commissural width of the mitral valve ("saddle shape") changed significantly throughout age for systolic phases (P < .001) but within a narrow range (median range, 0.20-0.25). Annular metrics changed statistically significantly between the diastolic and systolic phases of the cardiac cycle. Visually, the annular shape was maintained with respect to age and body surface area. Principal-component analysis revealed that the pediatric mitral annulus varies primarily in size (mode 1), ratio of annular height to commissural width (mode 2), and sphericity (mode 3).

CONCLUSIONS

The saddle-shaped mitral annulus is maintained throughout childhood but varies significantly throughout the cardiac cycle. The major modes of variation in the pediatric mitral annulus are due to size, ratio of annular height to commissural width, and sphericity. The generation of age- and size-specific mitral annular shapes may inform the development of appropriately scaled absorbable or expandable mitral annuloplasty rings for children.

Surgical Results of Mitral Valve Repair for Mitral Regurgitation in Pediatric Patients with Mitral Valve Prolapse

The rare incidence of mitral regurgitation (MR) caused by mitral valve prolapse in children lacks clinical management experience. In this study, we present our experience in surgical management and the difference between isolated anterior mitral leaflet (AML), posterior mitral leaflet (PML), and bileaflet prolapse in pediatric patients. Between January 2014 and February 2021, 52 pediatric patients, aged 7.04 ± 4.02 years (ranged from 0.17 to 14 years), were diagnosed as moderately severe (11, 21.2%) or severe (41, 78.8%) MR, of which, 34 (65.4%) were owing to AML prolapse, one (1.9%) was PML prolapse, and 17 (32.7%) caused by bileaflet prolapse. All had received mitral valve repair, and were divided into the group of AML prolapse and bileaflet prolapse. Demographic and clinical characteristics of all patients were retrospectively collected and analyzed. The left ventricular diameter in the bileaflet group was significantly larger than the AML group (4.04 ± 0.73 cm vs. 3.45 ± 0.75 cm, P = 0.026). The median follow-up time was 33 months (ranged from 6 to 88 months). The postoperative and follow-up results had no significant difference between two groups. And only 2 patients received reoperation due to posterior annuloplasty ring dehiscence. For pediatric patients, the majority of the patients had isolated AML prolapse instead of PML prolapse. There was no difference in recurrent regurgitation or reoperation between isolated AML and bileaflet prolapse after MV repair, and we suggest more aggressive surgical strategy should be considered in pediatric patients with bileaflet prolapse than AML prolapse.