Summary
Background
Although widely accepted worldwide, indications for percutaneous valve replacement are limited to treatment of dysfunction of prosthetic conduits inserted in the right ventricular outflow tract (RVOT). There has been little evaluation of the use of the Melody ® valve for patched non-circular pulmonary pathways.
Aim
To evaluate the outcomes of Melody valve insertion in patients with a patched non-circular RVOT.
Methods
We analysed procedural and outcomes data from 34 patients who underwent Melody valve implantation for a non-circular RVOT. RVOT preparation was done in all patients, using different techniques (conventional, Russian doll and/or PA jailing). Melody valve insertion was performed concomitantly in most patients.
Results
All procedures were successful. Sixteen patients had complex additional procedures, including the jailing technique ( n = 5), the Russian doll technique ( n = 6) and multiple stent implantations (Russian jailing; n = 5). The remaining patients were treated using the conventional technique with systematic prestenting. Three early complications occurred: one haemoptysis; one residual RVOT obstruction needing recatheterization 48 hours after percutaneous pulmonary valve implantation; and one stent embolization during advancement of the Ensemble ® delivery system. The mean follow-up period was 2.6 years postprocedure. There was no stent fracture, migration or embolization. Two patients developed a significant paraprosthetic leak and one received a second Melody valve.
Conclusions
Careful patient selection, balloon sizing and RVOT preparation with prestenting are required to create a safe landing zone for the Melody valve. Short-term follow-up shows excellent results with no stent fracture or migration and appears promising.
Résumé
Contexte
Bien que largement acceptées dans le monde, les indications de valvulation percutanée sont limitées au traitement des dysfonctionnements de conduits prothétiques de la voie d’éjection droite (VD-AP). L’utilisation de la valve Melody (Medtronic Inc., Minneapolis, Minnesota, États-Unis) a été peu évaluée pour les voies pulmonaires patchées non circonférentielles.
But
Nous avons évalué le devenir de l’implantation de Melody chez des patients avec une voie VD-AP patchée non circonférentielle.
Méthodes
Nous avons analysé les données de procédure et le devenir de 34 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 quatre techniques (la technique conventionnelle, la technique des poupées russes et la technique d’emprisonnement d’une AP associée ou non à la précédente). La valvulation a été simultanée chez la grand emajorité des patients.
Résultats
Toutes les procédures ont été réalisées avec succès. Tous ont été préstenté avant la valvulation. Dix-huit ont été traité de manière conventionnelle. Cinq ont eu une technique d’emprisonnement, 6 celle des poupées russes et 5 une technique combinée. Trois complications précoces sont survenues : une hémoptysie spontanément résolutive; un obstacle résiduel qui a nécessité un nouveau cathétérisme 48 heures après la Melody; et une embolisation précoce de stent. Le suivi moyen après la procédure était de 2,6 ans. Aucun patient n’a eu de fracture de stent, de migration ou d’embolisation de stents. Deux patients ont eu une fuite paraprothétique dont un a nécessité la pose d’une deuxième Melody.
Conclusions
Une sélection soigneuse des patients, une calibration au ballonet et une préparation de la voie VD-AP avec préstenting utilisant une technique classique, la technique des poupées russes ou d’emprisonnement sont nécessaires pour créer une zone d’accrochage pour insérer la valve Melody aux patients ayant des voies VD-AP patchées. À court terme, les résultats sont encourageants et prometteurs sans fracture de stent ni embolisation.
Background
Percutaneous pulmonary valve replacement using the transcatheter technique is now accepted and practiced worldwide for dysfunctional right ventricular outflow tracts (RVOTs) . The Melody ® valve (Melody transcatheter pulmonary valve; Medtronic Inc., Minneapolis, MN, USA) is available in a single diameter of 18 mm, dilatable up to 22 mm. Currently, indications are limited to dysfunctional RVOT circumferential conduits with a diameter ≤ 22 mm . Until recently, patched or native non-circular RVOTs were considered a relative contraindication to transcatheter valvulation, but off-label uses of the valve in patched or large outflow tracts are increasingly reported in the literature . The majority of patients requiring valvulation do not have a circular conduit. Indeed, a large number of patients have a patched native outflow tract after tetralogy of Fallot repair with the transannular patch technique. Some patients with operated tetralogy of Fallot or other operated congenital heart diseases have right ventricle (RV) to pulmonary artery (PA) conduits that have been enlarged with a patch during reintervention for stenosis. The issues with percutaneous treatment of native outflow tract or non-circular outflow tract are the size of the outflow tract, the absence of a landing zone and the non-circular shape of the outflow tract. We sought to review our experience with non-circular RVOTs, describing technical issues related to this specific type of anatomy and to study the outcome of percutaneous pulmonary valve implantation (PPVI) in a larger population.
Methods
All patients who had received a Melody valve in our centre since 2009 were reviewed and included in this study. Patients who had received a Melody valve in a non-circular outflow tract (defined as patients with no conduit, heterografts or homografts) were identified in the cohort. Data were extracted from the database and reviewed for this paper.
All patients had a preimplantation evaluation, including clinical examination, echocardiography and cardiac magnetic resonance imaging (MRI) or cardiac computed tomography in case of contraindication to magnetic resonance imaging. All procedures were performed under general anaesthesia. Informed consent approved by an ethical committee was obtained from each patient and/or their parents. Informed consent specified that patients were eligible for Melody valve implantation if a proper landing zone was present, either because of the existence of a circular conduit/homograft/heterograft or because of a calibrated patched RVOT. In the context of native tissue, the informed consent clearly specified that the patient needed a stent prior to Melody valve insertion to create a landing zone.
Cardiac catheterization was performed via percutaneous puncture of the femoral or jugular vein. The femoral artery was also accessed percutaneously for a coronary angiogram, to rule out any potential compression on the coronary arteries.
The haemodynamics and anatomy of the outflow tract and pulmonary arteries were assessed carefully. Dimensions of the RVOT were measured in at least two planes (lateral view and craniocaudal view). In cases with stenosis, assessment of the outflow tract was done using the conventional technique, using a high-pressure balloon (Atlas ® balloon; Bard Medical, Covington, GA, USA). In cases with regurgitation alone, balloon calibration was done with a low-pressure compliant balloon (Tyshak ® or PTS ® ; NuMED Inc., Hopkinton, NY, USA). The position of the coronary arteries was screened using coronary and/or aortic angiograms during RVOT balloon inflation.
Prestenting was done using available stents (ev3 Max™ LD, ev3 Endovascular Inc., Plymouth, MN, USA; CP Stent™, NuMED, Inc., Hopkinton, NY, USA). Patients were considered suitable for Melody valve placement if an appropriate landing zone could be created or existed. Patients with pure pulmonary regurgitation and RVOT/PA > 26 mm in diameter were considered for surgical valvulation. Different techniques were used to make implantation possible in case of large RVOT. These techniques have been reported in detail previously. Briefly, the Russian doll technique consisted of reducing the RVOT diameter by overlapping multiple stents (usually covered). The jailing technique consisted of using a PA branch to construct a safe landing zone in the RVOT. A first open-cell stent was positioned in the proximal left or right PA over a 22 mm balloon. A second stent was implanted using a 22 mm balloon inside the first one with an overlap of around 50% directed to the RVOT. The Melody valve (Model PB10) was then inserted as low as possible and well below the main PA bifurcation inside the stent of known diameter, using a 22 mm Ensemble ® transcatheter valve delivery system (NU10; NuMED Inc., Hopkinton, NY, USA). Postdilatation of the Melody valve using a balloon of appropriate diameter (22 or 24 mm) was done to reduce the amount of paraprosthetic leak. If the RVOT was very large, thick stents (typically covered stents) were placed inside the bare-metal stent prior to Melody valve implantation. The last technique combined the Russian doll and jailing techniques (‘Russian jailing’). For a large RVOT and a large PA, the method of choice was the Russian doll technique. For a large RVOT with favourable PA dimensions, the jailing technique was preferred. A combination of the two was preferred in patients with a very large RVOT and favourable PA dimensions. Patients with adequate size were treated according to the conventional technique.
Haemodynamic and angiographic assessments were repeated after PPVI in all patients. All patients received heparin and antibioprophylaxis during and after the procedure according to the institutional protocol and were discharged on lifelong aspirin.
Patients were scheduled at the outpatient clinic 1, 3, 6, 12 and 24 months after PPVI, with a detailed clinical examination, transthoracic echocardiography and chest X-ray at 6, 12 and 24 months. Cine angiography was only considered in patients with suspected stent fracture, pulmonary regurgitation, increased RVOT and signs of embolism.
Results
Thirty-four patients were identified as having a non-circular conduit in our database, representing 20% of the total population.
Demographics
Mean age at implantation was 26 ± 10 years ( Table 1 ). Overall, 58.9% of the patients had tetralogy of Fallot or pulmonary atresia with ventricular septal defect ( n = 20/34; 95% confidence interval [CI] 40.7–75.4%); 67.6% patients had native patched RVOTs ( n = 23/34, 95% CI 51.9–83.4%); and 32.3% had patched RVOT conduits ( n = 11/34, 95% CI 16.6–48.1%). Typically, the posterior wall of the conduits was preserved and enlarged anteriorly with a patch. No patient had a surgical valve. Four patients were known to have only one functional PA (11.7%, 95% CI 0.9–22.6%).
