What Factors Should Be Considered to Improve Outcome of Mechanical Mitral Valve Replacement in Children?

Surgical Melody Mitral Valve: A Paradigm Shift for Infants With Unrepairable Mitral Valve Disease

BACKGROUND

The Melody valve (Medtronic, Minneapolis, MN) for mitral valve replacement (MVR) (MelodyMVR) has been an effective strategy to treat unrepairable mitral valve disease in small children. This study analyzed survival, durability, and complications of the MelodyMVR strategy.

METHODS

Patients who underwent MelodyMVR between 2014 and 2023 were included. Transplant-free survival was analyzed with Kaplan-Meier analysis. The Fine and Gray subdistribution method was applied to quantify the cumulative incidence.

RESULTS

Twenty-five patients underwent MelodyMVR. Median age and weight were 6.3 months (interquartile range, 4.4-15.2 months) and 6.36 kg (interquartile range, 4.41-7.57 kg). Fifteen patients (60%) had congenital mitral valve disease and 13 (52%) had dominant mitral regurgitation. The median diameter of the implanted Melody was 16 mm (interquartile range, 14-18 mm). Mortality at 6 months, 1 year, and 5 years was 8.3% (95% CI, 2.2%-29.4%), 12.5% (95% CI, 4.2%-33.9%), and 17.6% (95% CI, 7.0%-40.7%), respectively. Two hospital survivors (8%) required early Melody replacement. Competing risk analysis showed that ∼50% of patients underwent mechanical MVR by 3.5 years after MelodyMVR. Freedom from bleeding and thrombosis at 4 years was 87.5% (95% CI, 74.2%-100%). Eleven patients underwent subsequent mechanical MVR with no deaths. One (9%) required pacemaker implantation after mechanical MVR.

CONCLUSIONS

MelodyMVR provides reasonable early and medium-term survival in small children and a high rate of successful bridge to mechanical MVR. MelodyMVR is associated with minimal pacemaker requirement, bleeding, and thrombosis. Early Melody functional deterioration necessitates early repeat MVR, which can be achieved with minimal morbidity and mortality.

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.

National In-Hospital Outcomes of Mechanical Mitral Valve Replacement in the Pediatric Population

Background: National data about the outcomes of children undergoing mechanical mitral valve replacement (m-MVR) are scarce. Methods: A retrospective review of hospitalizations from the Kids' Inpatient Database was performed for patients ≤18 years of age in the United States. A total of 500 patients underwent m-MVR in 2009, 2012, 2016, and 2019. Patients with single ventricle physiology were excluded (n  =  13). These patients were categorized into three groups according to age: neonates (<1 month, n  =  20), infants (1-12 months, n  =  76 patients), and children (1-18 years, n  =  404). Outcomes were compared between the three groups. Results: The proportion of m-MVR involving children undergoing MV procedures (repair and replacement) has increased from 17.3% in 2009 to 30.8% in 2019 (Ptrend < .01). History of cardiac surgery was present in 256 patients (51.2%). Concomitant procedures were performed in 119 patients (23.8%). Intra- or postoperative extracorporeal membrane oxygenation was required in 19 patients (3.8%). The overall in-hospital mortality was 4.8% and was significantly higher in neonates and infants compared with older children (10% vs 11.8% vs 3.2%, P = .003). The length of hospital stay was longer in the neonatal group (median, 57 days, interquartile range, [24.8-90] vs 29.5 days [15.5-61] vs 10 days [7-18], P < .01). Nonhome discharges were more common in neonates and infants (40% vs 36.8% vs 13.1%, P < .01). Conclusion: Mechanical mitral valve replacement is increasingly performed over time with acceptable in-hospital morbidity and mortality, especially in older children and adolescents. Neonates and infants are associated with worse hospital survival, prolonged hospitalization, and significant rates of nonhome discharges.

World Journal for Pediatric and Congenital Heart Surgery-The Official Journal of the Congenital Heart Surgeons' Society

The World Journal for Pediatric and Congenital Heart Surgery (WJPCHS) was established in 2009, as a means of advancing the educational and scholarship goals of the World Society for Pediatric and Congenital Heart Surgery. WJPCHS has grown steadily since the first issue was published in April 2010. In 2017, the Congenital Heart Surgeons' Society and the European Congenital Heart Surgeons Association both designated WJPCHS as the official journal of their respective organizations. The CHSS and ECHSA represent the face and the voice of congenital heart surgery in North America (United States and Canada) and in Europe, respectively. Each organization has advanced the science of surgical management of congenital heart disease through multicenter outcomes analyses, which have strongly and positively influenced the care of patients around the world.

Chromogenic Factor X Assay for Monitoring Warfarin Anticoagulation in a Child With a Prosthetic Mitral Valve

Mechanical mitral valve replacement in infants and young children is associated with substantial morbidity and mortality. Lifelong anticoagulation is required, with all the accompanying challenges of maintaining levels in infants and children whose dietary input continually changes. Even with careful control of all aspects that can perturb the coagulation cascade, these patients have a substantial lifelong risk of thrombotic and hemorrhagic complications that can also affect the durability of the valve. Anticoagulation is usually achieved utilizing warfarin with the degree of anticoagulation measured via the international normalized ratio (INR). Unfortunately, in some cases, the INR can be falsely elevated and lead to inappropriate reassurance. We describe a 4-year-old patient with complex congenital heart disease palliated via a single ventricular pathway with a mechanical atrioventricular valve replacement. The patient experienced acute valvular thrombosis while receiving warfarin with INR at target levels. Chromogenic factor X (CFX) levels were discordant with INR measurements, suggesting a subtherapeutic level of anticoagulation despite maintaining the standard INR target. Therefore, CFX levels were used to interpret INR measurements and guide an individualized approach to anticoagulation. We propose a new role of CFX: to verify and guide warfarin anticoagulation in high-risk pediatric patients including those undergoing mechanical mitral valve replacement.