Summary
Background
Although globally accepted, the indication for implantation of the Melody ® (Medtronic Inc., Minneapolis, MN, USA) transcatheter pulmonary valve is limited to the treatment of haemodynamically dysfunctional right ventricular outflow tract (RVOT) with right ventricle to pulmonary artery (PA) obstruction. The use of the Melody valve for haemodynamically significant isolated pulmonary regurgitation has not been evaluated.
Aim
We evaluated the outcomes of Melody valve insertion in patients with a large patched RVOT.
Methods
We analysed procedural and short-term outcomes data from 13 patients who underwent Melody valve implantation for a large RVOT with significant pulmonary regurgitation as the primary lesion. RVOT preparation was done in all patients using the Russian dolls technique and/or the PA jailing technique. Melody valve insertion was performed concomitantly in 10 patients and after 1 to 3 months in three patients.
Results
All procedures were successful. The mean follow-up period was 30 ± 4 months after the procedure. There was no incidence of stent fracture, migration or embolization. Only one patient who underwent the jailing technique developed a significant paraprosthetic leak and is scheduled for redilatation of the Melody valve.
Conclusions
Careful patient selection, balloon sizing and RVOT preparation with prestenting using the Russian dolls technique and/or the PA jailing technique are required to modify the RVOT for transcatheter valve implantation. Short-term follow-up showed competent valves with no stent fracture or migration and appears promising. Wider experience with long-term outcomes may be required to standardize the procedure in such a subset of patients.
Résumé
Bien que largement acceptées dans le monde, les indications de valvulation percutanée sont limitées au traitement des dysfonctionnements de conduits prothétiques interposés entre le ventricule droit (VD) et l’artère pulmonaire (AP). L’utilisation de la valve Melody (Medtronic Inc, Minneapolis, Minnesota, États-Unis) n’a pas été évaluée pour les fuites pulmonaires isolées.
But
Nous avons évalué le devenir de l’implantation de Melody chez des patients avec une voie VD-AP patchée et large.
Méthodes
Nous avons analysé les données de procédure et le devenir à court terme de 13 patients ayant reçu une valve Melody. La voie VD-AP a été préparée chez tous les patients avant la valvulation par un préstenting en utilisant deux techniques (la technique des poupées russes et/ou la technique d’emprisonnement d’une AP). La valvulation a été simultanée chez dix patients et après un délai de un à trois mois chez trois.
Résultats
Toutes les procédures ont été réalisées avec succès. Le suivi moyen après la procédure était de 30 plus ou moins quatre mois. Aucun patient n’a eu de fracture de stent, de migration ou d’embolisation de stents. Seul un patient du groupe « emprisonnement » a développé une fuite paraprothétique et est planifié pour une redilatation de la valve Melody.
Conclusions
Une sélection soigneuse des patients, une calibration au ballonet et une préparation de la voie VD-AP sont nécessaires pour pouvoir insérer une valve Melody aux patients ayant des voies VD-AP patchées. A court terme, la valve est compétente sans fracture de stent ni embolisation. Les techniques utilisées pour le préstenting sont prometteuses. Une expérience plus large est nécessaire pour standardiser la procédure et avoir plus de recul.
Background
Melody ® (Medtronic Inc., Minneapolis, MN, USA) transcatheter pulmonary valve replacement, although globally accepted, is limited to the management of haemodynamically dysfunctional right ventricular outflow tract (RVOT) conduits < 22 mm in diameter as an alternative to surgical replacement . The device is available in a single size (diameter of 18 mm; dilatable up to 22 mm). Since the first human case report, several published reports have demonstrated uniform efficacy and outcomes in selected populations . With the rising volume of patients who are surviving complex congenital heart surgeries, there is now a need to broaden the indications for Melody valve implantation.
We report on the use of the Melody valve in patients with a patched right ventricular outflow tract with pulmonary regurgitation and absence of any obstruction, as a case series.
Methods
The data were derived from an ongoing prospective multicentre non-randomized trial (REVALV; Medico-economic Evaluation of a Non chirurgical Pulmonary Valve Replacement) to evaluate outcomes after Melody transcatheter pulmonary valve implantation in France; formal approval was given by the French Ministry of Health in May 2008. Patients with a dysfunctional RVOT conduit were identified and evaluated by investigators. All patients had a preinclusion evaluation that involved a clinical examination, a surface electrocardiogram, echocardiography, exercise testing and magnetic resonance imaging (MRI) or cardiac tomography. Prospective patients were further evaluated by conventional cardiac catheterization to assess the degree of haemodynamic derangement and by RVOT angiography to define the RVOT and pulmonary artery (PA) morphology and thereby establish a strategy prior to Melody valve placement ( Table 1 ). Balloon calibration was done in all patients for accurate sizing, using low pressure and compliant balloons. RVOT and individual PA diameters were measured at baseline and with balloon inflation ( Fig. 1 ). All patients were screened to look for the position of the coronary arteries in regard to the RVOT, the right PA (RPA) and the left PA (LPA) (aortogram).
| Age ≥ 5 years |
| Weight ≥ 20 kg |
| Non-circumferential RVOT conduit OR history of patch enlargement of the RVOT AND RVOT and/or one PA ≤ 26 mm in diameter in systole on MRI |
If stenosis was the primary indication and the right ventricle (RV)/aorta systolic pressure ratio was greater than 0.66, the patient was considered for standard pulmonary valve insertion. Elsewhere, one of two techniques or a combination of the two was used, as described below ( Fig. 2 ).
Preparation of the right ventricular outflow tract (RVOT) for melody valve insertion
Pulmonary artery (PA) jailing technique
The smallest or stenosed PA branch was used as an anchor for multiple stents and subsequently for Melody valve insertion. When the diameter of a PA branch was < 22 mm and the RVOT was > 22 mm, stenting was started from that PA branch all the way to the RVOT with overlapping uncovered stents, thus jailing the opposite PA (PA jailing technique). This novel technique was utilized only if the main PA (MPA), RPA or LPA diameter measured < 25 mm, otherwise the patient was deemed anatomically unsuitable for the jailing technique.
Uncovered bare-metal stents with open-cell design were used for this application (MaxLD 36 mm, ev3, Irvine, CA, USA). The first stent was crimped over a BIB balloon (Numed Inc., Hopkinton, NY, USA) and deployed in the suitable branch PA. The same balloon was used for deploying additional stents of same type and length below the first one, going all the way to the RVOT. An overlap of 50% was achieved. After deployment of the last stent, an MPA angiogram was performed to look for patency of the contralateral vessel ( Figs. 3 and 4 ).
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