Replacement of the Mitral Valve Under One Year of Age: Size Matters

Mitral valve replacement in children: balancing durability and risk with mechanical and bioprosthetic valves

OBJECTIVES

To investigate if there is still a place for bioprosthetic mitral valve replacement in children by comparing the prosthetic durability and transplant-free survival after bioprosthetic and mechanical mitral valve replacement.

METHODS

We reviewed all mitral valve replacements in children between 1981 and 2020. Bioprosthetic mitral valve replacement cases were individually matched to mechanical mitral valve replacement cases. The incidence rate of a 2nd replacement was calculated using the cumulative incidence function that considered death or transplantation as a competing risk.

RESULTS

The median age at implantation was 3.6 years (interquartile range 0.8-7.9) for the bioprosthetic valve cohort (n = 28) and 3 years (interquartile range 1.3-7.8) for the mechanical valve cohort (n = 28). Seven years after bioprosthetic mitral valve replacement, the cumulative incidence of death or transplantation was 17.9% [95% confidence interval (CI) 6.3-34.1] and the cumulative incidence of a 2nd replacement was 63.6% (95% CI 39.9-80.1). Seven years after mechanical mitral valve replacement, the cumulative incidence of death or transplantation was 28.6% (95% CI 13.3-46) and the cumulative incidence of a 2nd replacement was 10.7% (95% CI 2.6-25.5). Fifteen years after mechanical mitral valve replacement, the cumulative incidence of death or transplantation was 33.6% (95% CI 16.2-52.1) and the cumulative incidence of a 2nd replacement was 41.1% (95% CI 18.4-62.7). The cumulative incidence curves for bioprosthetic and mechanical mitral valve replacement were statistically different for a 2nd valve replacement (P < 0.001) but not for death or transplantation (P = 0.33).

CONCLUSIONS

There is no difference in transplant-free survival after bioprosthetic and mechanical mitral valve replacement in children. The lifespan of bioprosthetic mitral valves remains limited in children because of structural valve failure due to calcification. After 15 years, 40% of mechanical valves were replaced, primarily because of patient-prosthesis mismatch related to somatic growth.

Anisocytosis as a possible predictor of low cardiac output syndrome in children undergoing mitral valve surgery

PURPOSE

Mitral valve surgery in children involves correcting congenital and acquired pathologies, with a reported mortality rate of 0.9%. Low cardiac output syndrome (LCOS) is a serious complication with the incidence of 20-25%. The aim of the study was to estimate possible prognostic factors of LCOS in children undergoing mitral valve procedure.

MATERIAL AND METHOD

This single-center retrospective analysis enrolled children aged <18 years who underwent mitral valve surgery during 24 year period. Preoperative clinical and laboratory parameters, and operative factors were analyzed.

RESULTS

Thirty consecutive pediatric patients (11 (37%) males and 19 (63%) females) in median (Q1 - Q3) age of 57 (25-115) months, who underwent mitral valve replacement, were included. The 30-day mortality was 7% (2 patients) and was related to postoperative multiorgan failure. LCOS occurred in 8 (27%) children. The receiver operator curve (ROC) analysis established parameters that have predictive value for LCOS occurrence: cardiopulmonary bypass (CPB) time, with 89 ​min as optimal cut-off point (AUC ​= ​0.744, p ​= ​0.011) yielding sensitivity of 100% and specificity of 42.9%; left ventricular ejection fraction (LVEF) ​< ​60 % (AUC ​= ​0.824, okp ​= ​0.001) with sensitivity of 62.5% and specificity of 93.75%; and red blood cell distribution width (RDW) above 14.5 % (AUC ​= ​0.840, p ​< ​0.001; sensitivity of 87.5% and specificity of 75%).

CONCLUSIONS

In mitral valve replacement in pediatric patients, CPBtime above 89 ​min, preoperative LVEF below 60% and preoperative RDW above 14.5% can be regarded as the potential predictors of LCOS.

Midterm Outcomes After Surgical Management for Mitral Valve Regurgitation in Infancy

Background

Mitral valve repair is preferred for pediatric mitral valve disease. However, it is technically difficult because of complex lesions, poor surgical exposure, and tissue fragility, especially in infants. We investigated the midterm outcomes of mitral valve surgery for mitral regurgitation in infancy.

Methods

We retrospectively reviewed 18 patients (aged <12 months old) undergoing mitral valve surgery for mitral regurgitation at our institution between October 2005 and March 2019. The patients had 10 acquired and 8 congenital valve lesions as follows: torn chordae ( n = 6), leaflet prolapse ( n = 4), posterior leaflet hypoplasia ( n = 3), anterior leaflet cleft ( n = 2), infective endocarditis ( n = 1), papillary muscle rupture ( n = 1), and hammock valve ( n = 1).

Results

All patients initially underwent mitral valve repair. There was no operative mortality, and 1 case of late death. The median follow-up period was 7 years and 9 months. Reoperation was performed in 3 patients, re-repair (twice) in 1 patient with a hammock valve, and mitral valve replacement in 2 patients. Fifteen patients had at most mild mitral regurgitation at the last follow-up. A transmitral mean pressure gradient of over 5 mm Hg was observed in 3 cases, including the patient with a hammock valve. Postoperative mitral annular diameter increased within the normal range in all patients. Survival and reoperation-free rates at 5 and 10 years were 94.4% and 83.0%, respectively.

Conclusions

Mitral valve repair for mitral regurgitation in infancy is safe and feasible with satisfactory midterm outcomes, even under serious preoperative conditions.