Risk of infective endocarditis after hybrid Melody mitral valve replacement in infants: The French experience

Listen to this “high-pitched” melody!

Surgical management of mitral valve disease is challenging in infants <1 year old. We aimed at reviewing the French experience with Melody mitral valve replacement in critically ill infants. A retrospective cohort study reporting the French experience with Melody mitral valve replacement. Seven symptomatic infants [complete atrioventricular septal defect (n = 4, Down syndrome: n = 3), hammock valve (n = 3)] underwent Melody mitral valve replacement [age: 3 months (28 days to 8 months), weight: 4.3 kg (3.2-6.4 kg)] because of severe mitral valve regurgitation (6) or mixed valve disease (1) and 14 mm (11-16 mm) mitral valve annulus. In 2 patients whose valve was felt irreparable, Melody mitral valve replacement was performed straightaway. The others underwent 2 (1-3) previous attempts of valve repair; 3 were on extracorporeal membrane oxygenation. Melody mitral valve replacement led to competent valve and low gradient [3 mmHg, (1-4 mmHg)]. One patient died 3 days post-implant from extracorporeal membrane oxygenation-related stroke. Of the 6 discharged home patients, 3 (50%) were readmitted for a definite diagnosis (1) or high suspicion (2) of infective endocarditis, of which 2 died. Over the follow-up, 1 underwent balloon expansions of the valve at 9- and 16-months post-implant, and mechanical mitral valve replacement at 2 years; another is currently planned for transcatheter Melody valve dilation. Melody mitral valve replacement may be considered in selected infants with small mitral valve annulus as an alternative to mechanical mitral valve replacement. Our experience highlights a high-risk of late infective endocarditis that deserves further consideration.

Mitral valve replacement in infants is rare and causes a relatively high mortality, especially for patients under the age of 1. Supra-annular valve replacement is a viable technique for infants with a small valve annulus. Here, we report two infants who underwent mitral valve replacement via the supra-annular technique. The age and body weight of these babies were 2 months and 3 months and 4.1 kg and 4.7 kg, respectively. Aortic mechanical valves were reversely implanted with a short segment of PTFE graft. The purpose of this strategy was to insert a larger mechanical valve and delay resternotomy. A two-year follow-up exam showed normal ventricular function without mechanical valve-related complications. This method is useful in treating neonates and infants. Although the technique of mitral valve repair has improved over several decades, mitral valve replacement still is necessary at times. In neonates and infants with a small annulus, implantation of commercially available prosthetic valves in the annular position can be a challenge, and an age less than 1 year is a risk factor for early death [Selamet 2008]. Supra-annular mitral valve replacement (SMVR) is an alternative when a traditional annular implantation is not feasible [Sung 2008]. Herein, we report the cases of two patients, who underwent SMVR with a follow-up after two years.

Mitral valve replacement in infants is challenging and there are limited alternative valves available. Since the Boston group published their first report on alternative valves for mitral valve replacement in infants, there has been a growth in the literature on the topic, mostly based on the use of a stented bovine jugular vein graft (Melody® valve). The challenges of the Melody valve are firstly in its length of 28 mm unexpanded, which has the potential to cause left ventricular outflow tract obstruction, and secondly, the valve needs mechanical dilatation, which is laborious. A modified No-React® Injectable Biopulmonic™ Prosthesis (Bio Integral Surgical, Inc., Mississauga, ON, Canada) which is shorter (19 mm) and simpler in that it is self-expanding was implanted in a 14-month-old child to replace her mitral valve. The operation was successful and the short-term function of the prosthesis is good.

Background: Mitral valve replacement in infants is highly challenging due to size limitations and the lack of suitable prosthetic valves. The Melody™ valve, originally developed for transcatheter pulmonary valve replacement, offers an off-label alternative for surgical implantation in the mitral position, with the possibility of balloon expansion and valve-in-valve procedures during somatic growth. Aim: To evaluate the long-term outcomes and technical feasibility of the Melody™ valve in the mitral position in infants and very young children following failed surgical repair. Methods: This single-center, retrospective observational study included four pediatric patients who underwent Melody™ valve implantation in the mitral position between October 2015 and February 2020. Data on patient characteristics, surgical techniques, perioperative management, complications, and long-term outcomes were collected and analyzed through April 2024. All patients were followed clinically and with echocardiography. Additional interventions, including balloon dilations and valve-in-valve procedures, were documented. Results: All patients (mean age: 7 months; mean weight: 6.8 kg) had undergone prior mitral valve repair and presented with severe mitral dysfunction. Melody™ valves were successfully implanted with no perioperative mortality. Over a mean follow-up of 5.9 years (range: 4.2-8.5), six balloon dilations were performed (1-2 per patient), and one valve-in-valve procedure was conducted due to progressive stenosis. Two patients required valve excision: one for endocarditis, one for degeneration. The mean valve longevity before replacement was 44.6 months. Three patients developed complete atrioventricular block requiring pacemaker implantation. No thromboembolic events or LVOT obstructions were noted. Mean transmitral gradients at final follow-up were <5 mmHg in all patients. Conclusion: The Melody™ valve provides an adaptable solution for mitral valve replacement in infants, allowing for staged expansion and valve-in-valve strategies. Despite a notable risk of AV block, the long-term outcomes are promising, especially in patients too small for conventional prostheses. Close follow-up and further multicenter studies are needed to optimize patient selection and long-term management.

Between a Rock and a Hard Place—Challenges of Mitral Valve Replacement in Infants

Melody Valve for Mitral Valve Replacement

First Surgical Melody Valve-In-Valve Implantation for Early Degeneration in Mitral Position

The aim of this study was to evaluate early and late outcomes after mechanical systemic heart valve replacement in pediatric patients. Between October 1981 and December 2003, 32 children (mean age 7.2 +/- 5.4 years; 4 months - 15.9 years) underwent mechanical mitral (MVR, n = 17), aortic (AVR, n = 13) or double valve replacement (DVR, n = 2) with St. Jude Medical valves. Twenty-two patients (69 %) had undergone previous cardiac surgery. Anticoagulation self-management was used since 1995. The operative mortality was 3.1 %. Perioperative complications were complete heart block (n = 5), ventricular fibrillation (n = 1) and myocardial infarction (n = 1) and were exclusively related to patients with MVR. Mean calculated valve size ratio (geometric prosthesis orifice area/normal valve size area) was 1.72 (1.07 - 2.85) for AVR and 1.4 (0.88 - 3.12) for MVR. Mean follow-up was 9.1 +/- 6.6 years (range 0.4 - 23.2 years, cumulative 283 patient-years). There were two late deaths in patients with MVR. Actuarial survival after 10 years was 93.8 %. Late complications were endocarditis (n = 2), minor hemorrhagic event (n = 1), and stroke (n = 1). Anticoagulation self-management is well accepted by all patients/parents. Overall 10-year freedom from any anticoagulation-related adverse event with phenprocoumon was 89.1 % (1.2 %/patient year). Nine patients required reoperations: redo-MVR (outgrowth of prostheses (n = 3), pannus overgrowth (n = 2), closure of paravalvular leak after AVR (n = 2), partial aortic valve thrombosis (n = 1) and redo-DVR (n = 1 for endocarditis). Freedom from reoperation after 10 years was 80.9 %. Mechanical valve prostheses are a valuable option for left-sided heart valve replacement in pediatric patients. Perioperative morbidity was exclusively related to patients with MVR. Oversizing was often possible to avoid early reoperation for outgrowth. The operative mortality and long-term morbidity are acceptable. Anticoagulation self-management is safe and well accepted.

Mitral Valve Replacement in Infants and Children: Five-Year Outcomes of the HALO Clinical Trial

Data on mitral valve replacement (MVR) in young children is still limited. Our objective was to evaluate MVR in children below 5 years and identify factors affecting the outcomes. This retrospective study included 29 patients who had MVR from 2002 to 2020. We grouped the patients into two groups according to their age: age ≤ 24 months (n = 18) and > 24 months (n = 11). Primary cardiac diagnoses were Shone complex (n = 7; 24%), isolated congenital mitral valve abnormality (n = 11; 38%), and complete atrioventricular septal defect (n = 3; 10%). The median age was 19 month (25th–75th percentile: 11–32) and 59% were females (n = 17). The hemodynamic lesions were mitral regurgitation in 66%, mitral stenosis in 10%, and combined mitral stenosis and regurgitation in 24% of the patients. St. Jude mitral valve was the most common valve implanted (n = 19, 66%), followed by CarboMedics in 21% of the patients (n = 6). The mitral valve was implanted in the supra-annular position in 6 cases (21%). Preoperative and operative data were comparable between both groups. There was no association between valve size and position with postoperative heart block (P > 0.99, for both). The median follow-up duration was 19.4 months (8.6–102.5). Nine patients had mitral valve reoperation, six had MVR, and three had clot removal from the mitral valve. There was no effect for age group on reoperation (SHR 0.89 (95% CI 0.27–2.87), P = 0.84). Valve size significantly affected reoperation (SHR 0.39 (95% CI 0.18–0.87), P = 0.02). The supra-annular position was associated with an increased risk of reoperation (SHR 3.1 (95% CI 1.003–9.4), P = 0.049). There was no difference in survival according to the age (Log-rank P = 0.57) or valve size (Log-rank P = 0.66). Mitral valve replacement in children is associated with low morbidity and mortality. The risk of reoperation could be affected by the valve size and position rather than the age.

Stented bovine jugular vein graft (Melody valve) for surgical mitral valve replacement in infants and children

Mitral valve replacement (MVR) is the only option for infants with severe mitral valve disease that is not reparable; however, previously reported outcomes are not always favorable. Our institution has followed a tailored approach to sizing and positioning of mechanical valve prostheses in infants requiring MVR in order to obtain optimal outcomes. Outcomes for 22 infants ≤10 kg who have undergone MVR in Sydney, Australia, from 1998 to 2016, were analyzed. Patients were at a mean age of 6.8 ± 4.1 months (range: 0.8-13.2 months) and a mean weight of 5.4 ± 1.8 kg at the time of MVR. Most patients (81.8%) had undergone at least one previous cardiac surgical procedure prior to MVR, and 36.4% had undergone two previous procedures. Several surgical techniques were used to implant mechanical bileaflet prostheses. All patients received bileaflet mechanical prostheses, with 12 receiving mitral prostheses and 10 receiving inverted aortic prostheses. Surgical technique varied between patients with valves implanted intra-annularly (n = 6), supra-annularly (n = 11), or supra-annularly with a tilt (n = 5). After a mean follow-up period of 6.2 ± 4.4 years, the survival rate was 100%. Six (27.3%) patients underwent redo MVR a mean of 102.2 ± 10.7 months after initial MVR. Four (18.2%) patients required surgical reintervention for development of left ventricular outflow tract obstruction and three (13.6%) patients required permanent pacemaker placement during long-term follow-up. The tailored surgical strategy utilized for MVR in infants at our institution has resulted in reliable valve function and excellent survival. Although redo is inevitable due to somatic growth, the bileaflet mechanical prostheses used displayed appropriate durability.

Mitral valve replacement in infants and children 5 years of age or younger: Evolution in practice and outcome over three decades with a focus on supra-annular prosthesis implantation

Background. Mitral valve replacement can be very difficult to obtain in infants because the valve annulus diameter can be smaller than the available prosthesis. Case Report. We describe the case of a 2-month-old female weighing 3.5 kg affected by mitral valve dysplasia leading to severe valve stenosis. Despite full medication, the clinical conditions were critical and surgery was undertaken. The mitral valve was unsuitable for repair and the orifice of mitral anulus was 12 mm, too small for a mechanical prosthesis. Therefore, a Ross-Kabbani operation was undertaken, replacing the mitral valve with the pulmonary autograft and reconstructing the right ventricular outflow tract with an etherograft. Results. The postoperative course was uneventful and the clinical conditions are good at 4-month follow-up. Conclusion. The Ross-Kabbani operation can be an interesting alternative to mitral valve replacement in infants when valve repair is not achievable and there is little space for an intra-annular mechanical prosthesis implant.