Striving for physiologic coaptation: An experimental and innovative approach towards designing and implanting aortic neo-leaflets.

Aortic valve repair has emerged as the treatment of choice for congenital aortic valvular disease, avoiding the need for a reoperation associated with stented prosthesis overgrowth. The introduction of a leaflet implant represents a recent advancement in a field that originated early techniques, such as simple commissurotomies. In our experimental approach, we assessed two established leaflet-sizing techniques by analysing their resultant coaptation areas. Although both techniques produced competent valves, the large coaptation areas differed significantly from the native aortic valve. This observation prompted us to revisit the functional anatomy of the aortic valve, our goal being to refine leaflet design and implantation for enhanced efficacy and longevity in neo-leaflet procedures. We designed a novel aortic valvar neo-leaflet, utilizing porcine pericardium as our primary source material, and we implanted four tri-leaflet valves in four porcine hearts. All tri-leaflet valves were competent and closely resembled the coaptation area of the native aortic valve. This study serves as a pilot for further experimental aortic valve repair surgery using neo-leaflet implants.

Use of virtual reality in complex double outlet right ventricle cases.

Virtual reality has been incorporated into clinical practice for planning complex congenital cardiac operations at the Great Ormond Street Hospital for Children since 2018 [1]. Virtual reality allows for 3-dimensional exploration of patient-specific models, created through the segmentation of 3-dimensional imaging data sets. Along with 3-dimensional printed models and 3-dimensional PDFs, this technology has enabled a new approach in planning and reviewing surgical interventions. It is particularly important in intracardiac repairs involving ventricular septal defects [2] and double outlet right ventricle cases presenting with various phenotypes of interventricular communication [3,4]. We present the virtual reality environment of two complex cases of double outlet right ventricle, illustrating the potential of virtual reality as a clinical tool to aid anatomical understanding and surgical planning of complex congenital heart disease.

Ductal arch decoded: the use of its spatial fingerprint to design a Norwood type of patch.

Reconstruction of the aortic arch for the Norwood procedure remains a focus of attention in terms of the management of the distal anastomosis [1,2], patch design and material [3,4], and fashioning the Damus-Kaye-Stansel itself [5]. The reconstructed aorta supplies the coronaries and the head and neck vessels and directs flow to the descending aorta. As the fetus develops, the right ventricle shunts to the aorta through the ductal arch, supporting a great percentage of the systemic and the placental circulation. We have developed a method of designing a Norwood patch by decoding the 3-dimensional geometry of the arterial duct and its arch.

Aortic Arch Phenotypes in Double Outlet Right Ventricle (DORV)-Implications for Surgery and Multi-Modal Imaging.

Abnormal aortic arches (AAAs) cover a spectrum of malformations, including abnormal laterality, branching patterns, and flow-limiting narrowing, which themselves vary from tubular hypoplasia, through discrete coarctation, to complete interruption of the arch. Neonatal surgery within the first days of life is necessary for most of these morphologies. Patch aortoplasty is widely used as it can offer a good haemodynamic result, being tailored to each combination of presenting pathologies. Our study hypothesis was that arch malformations are frequent in DORV and exhibit a plethora of phenotypes. We reviewed 54 post-mortem heart specimens from the UCL Cardiac Archive, analysing morphological features that would potentially influence the surgical repair, and taking relevant measurements of surgical importance. AAAs were found in half of the specimens, including 22.2% with aortic arch narrowing. In total, 70% and 30% of narrow arches had a subpulmonary and subaortic interventricular defect, respectively. Z-scores were significantly negative for all cases with tubular hypoplasia. We concluded that arch malformations are a common finding among hearts with DORV. Surgery on the neonatal aortic arch in DORV, performed in conjunction with other interventions that aim to balance pulmonary to systemic flow (Qp/Qs), should be anticipated and form an important part of multi-modal imaging.

Demonstration of Use of a Novel 3D Printed Simulator for Mitral Valve Transcatheter Edge-to-Edge Repair (TEER).

Mitral regurgitation is a common valvular disorder. Transcatheter edge-to-edge repair (TEER) is a minimally invasive technique which involves holding together the middle segments of the mitral valve leaflets, thereby reducing regurgitation. To date, MitraClip™ is the only Food and Drug Administration (FDA)-approved device for TEER. The MitraClip procedure is technically challenging, characterised by a steep learning curve. Training is generally performed on simplified models, which do not emphasise anatomical features, realistic materials, or procedural scenarios. The aim of this study is to propose a novel, 3D printed simulator, with a major focus on reproducing the anatomy and plasticity of all areas of the heart involved and specifically the ones of the mitral valve apparatus. A three-dimensional digital model of a heart was generated by segmenting computed tomography (CT). The model was subsequently modified for: (i) adding anatomical features not fully visible with CT; (ii) adapting the model to interact with the MitraClip procedural equipment; and (iii) ensuring modularity of the system. The model was manufactured with a Polyjet technology printer, with a differentiated material assignment among its portions. Polypropylene threads were stitched to replicate chordae tendineae. The proposed system was successfully tested with MitraClip equipment. The simulator was assessed to be feasible to practice in a realistic fashion, different procedural aspects including access, navigation, catheter steering, and leaflets grasping. In addition, the model was found to be compatible with clinical procedural imaging fluoroscopy equipment. Future studies will assess the effect of the proposed training system on improving TEER training.