Handmade Bicuspid Valved Polytetrafluoroethylene Conduit for Right Ventricular Outflow Tract Reconstruction.

Background: Excellent outcomes of right ventricle to pulmonary artery conduits with polytetrafluoroethylene (PTFE) valves have been reported. The purpose of this study was to analyze the short-term results of our handmade PTFE bicuspid valved conduit (VC) for right ventricular outflow tract reconstruction. Methods: Between September 2019 and May 2023, bicuspid PTFE-VC was implanted in 17 patients at a median age of 2.5 years (range, 3 months to 13.6 years). The PTFE-VC was fashioned from a commercially available PTFE tube graft (14 mm in three patients, 16 mm in three patients, 18 mm in one patient, 20 mm in three patients, and 22 mm in seven patients) and 0.1 mm thick PTFE membrane for the leaflet material. Valve function was assessed by echocardiogram after the implantation. The conduit reoperation and the conduit dysfunction were analyzed. There were no early deaths, but there was one late death. Results: There were no postoperative in-hospital deaths. Follow-up echocardiograms were available for 14 of 17 patients. The median follow-up was 21 months (range, 7-49 months). Conduit stenosis was none or trivial in 11 patients while it was mild in two and moderate in one patient and severe in 0 patients. Conduit insufficiency was mild or trivial in all 14 patients. By the end of the study period, freedom from reoperation/reintervention was 100%. There were no episodes of aneurysmal dilatation of the conduit or endocarditis. Conclusions: Handmade bicuspid PTFE VC shows good short-term outcome, with no significant valve dysfunction and no reintervention. A longer follow-up is necessary to evaluate the long-term advantages of using the handmade bicuspid PTFE VC.

Redo-ALCAPA Repair With Left Subclavian Artery-to-Left Main Coronary Bypass for Left Coronary Atresia.

Different surgical techniques have been described for the primary repair of anomalous left coronary artery arising from the pulmonary artery (ALCAPA); however, very few techniques are described for management of coronary artery occlusion following ALCAPA repair. We present a case of a 7-year-old girl with left main coronary atresia status-post left coronary button transfer for ALCAPA in infancy. She underwent redo-sternotomy and left subclavian artery-to-left main coronary artery bypass plus mitral valve repair and had an uneventful postoperative course.

Anomalous right coronary artery from the pulmonary artery in an infant with tetralogy of Fallot.

An anomalous right coronary artery from the pulmonary artery (ARCAPA) is a rare congenital anomaly that does not have the typical presentation of the more common anomalous left coronary artery. We present an infant with tetralogy of Fallot with atypical findings on the preoperative echocardiogram. A cardiac computerized tomographic (CT) scan showed ARCAPA. This was confirmed intraoperatively and repaired successfully. Close attention to coronaries on echocardiography and a low threshold for additional imaging can successfully diagnose ARCAPA in the presence of additional congenital heart defects.

Neo-cusp Reconstruction Procedure for Aortic Regurgitation Induced by Transcatheter Occluder Device for Ventricular Septal Defect Closure.

Aortic regurgitation after transcatheter device closure of a perimembranous ventricular septal defect is a known complication. We present the case of an 11-year-old boy with severe aortic valve regurgitation due to cusp perforation complicating previous device closure of a ventricular septal defect. The patient underwent successful aortic valve repair (neo-cusp reconstruction technique) by replacement of a cusp and shaving off of a rim of the device 5 years after device closure.

Giant Right Atrial Aneurysm in an Infant.

Right atrial aneurysm (RAA) is a rare congenital anomaly with a diverse clinical spectrum. We present a case of antenatal detection of a giant RAA. The infant had 3 episodes of staring spells presumed to be thrombo-embolic phenomena originating from the RAA. The infant underwent successful RAA resection with preservation of the right coronary artery that was displaced from its usual position due to invagination of the RAA in the subepicardial space of the right atrio-ventricular groove.

Fontan procedure on deep hypothermic circulatory arrest: Short-term results and technique.

Background: Various operative strategies are described for the Fontan procedure. In this study, we describe our short-term results and technique of Fontan procedure on cardiopulmonary bypass (CPB) and deep hypothermic circulatory arrest (DHCA). Methods: This was a retrospective study of 32 patients, median age of 6 years (4-19 years) and median weight of 20 kg (13-51 kg), who underwent Fontan procedure on CPB and DHCA from July 2016 to July 2021. Results: The median CPB time was 125 min (77-186 min), the median DHCA time was 42 min (27-50 min), and the median Fontan pressure was 14 mmHg (10-18 mmHg). The median time to extubation was 4 h (1-20 h), the duration of chest tube drainage was 8 days (5-24 days), and the median intensive care unit stay was 4 days (3-8 days). The presence of heterotaxy was associated with longer duration of pleural drainage (P = 0.01). There was no operative mortality and no major adverse events such as seizures, gross neurological deficits, or arrhythmias in the postoperative period. Conclusions: Fontan procedure can be safely performed on CPB and DHCA with good operative results. This operative strategy may be used in special circumstances like in patients with situs and systemic venous anomalies and those requiring repair of a complex intracardiac defect. Long-term follow-up will be required to evaluate if this strategy has any impact on the neurodevelopmental outcome and the long-term sequelae of Fontan.

Early experience with pediatric cardiac transplantation in a limited resource setting.

BACKGROUND: Pediatric heart transplantation is a now a well-established and standard treatment option for end stage heart failure for various conditions in children. Due to logistic issues, it is not an option for in most pediatric cardiac centres in the third world. AIM: We sought to describe our early experience in the current era in India. METHODS: This is a short term retrospective chart review of pediatric patients who underwent heart transplantation at our centre. Mean/Median with standard deviation /range was used to present data. RESULTS: Twenty patients underwent orthotopic heart transplant between January 2016 and June 2019. The median age at transplant was 12.4years (range 3.3 to 17.3 years). The median weight was 23.2kg (range 10-80kg). The mean donor/recipient weight ratio was 1.62± 0.84. The mean ICU stay was 12.1days. The mean follow up post transplant was 2.03± 0.97years (range 10 days-3.57years). The 1 month and the 1 year survival was 100%. Biopsies were positive for significant rejection in 7 patients (35%). At the time of last follow-up, 3 patients (15%) had expired. The major post transplant morbidities were mechanical circulatory support (n=3), hypertension with seizure complex (n=3), post transplant lympho-proliferative disorder (n=1), pseudocyst of pancreas (n=1), coronary allograft vasculopathy (n=3) and systemic hypertension (n=7). All surviving patients (n=17) were asymptomatic at last follow up. CONCLUSION: The results suggest acceptable short term outcomes in Indian pediatric patients can be achieved after heart transplantation in the current era. Significant rejection episodes and coronary allograft vasculopathy need careful follow up.

Primary Arterial Switch Operation for TGA/IVS and Regressed Left Ventricle: How and When to Use Left Ventricular Assist Device.

PURPOSE: Numerous attempts have been made to extend the boundaries of arterial switch operation (ASO) in children presenting late with transposition of great arteries with intact ventricular septum (TGA/IVS) and regressed left ventricle (rLV). Many children tolerate the delayed ASO uneventfully, whereas others need mechanical circulatory support (MCS) to sustain the systemic circulation while the left ventricle undergoes retraining. DESCRIPTION: In this article, we describe six consecutive children with TGA/IVS and rLV who underwent primary ASO. RESULTS: Three were managed medically, while three required MCS in the form of Centrimag left ventricular assist device (LVAD). All patients survived the operation and were discharged home in a stable condition. CONCLUSIONS: Primary ASO can be safely performed in children with TGA/IVS and rLV, provided the center has MCS options. Supporting the rLV with LVAD is feasible and can be achieved safely.

Virtual three-dimensional model for preoperative planning in a complex case of a double outlet right ventricle.

A 3-year-old child with a complex variant of double outlet right ventricle achieved a successful biventricular repair after detailed delineation of the intracardiac anatomy on multimodality imaging. A virtual three-dimensional (3D) model based on computed tomography was used successfully in the absence of an actual 3D-printed model. This case report seeks to highlight and hence increase the utilization of the virtual 3D model in resource-limited settings.

Effect of inspiration cycle and ventilation rate on heat exchange in human respiratory airways.

A transient three dimensional (3D) theoretical axisymmetric model is developed for heat exchange across the human respiratory tract during inspiration phase and applied to study the changes in the airway temperature and velocity profile for varying ventilation rates and inhalation temperatures. A multi-compartment approach is used to study the same to avoid the airway scaling problem from micro to nano scale. This analysis also includes the role of water evaporation in mucus and non perfused tissue layers and the role of capillary bed in thermal variations during respiration. The results of heat transfer in airway and mucus layer depend on the local morphological parameters. The results are compared with the case of hypothetical regular geometry to show the significance of local morphology. The location where the inhaled air gets saturated with the body core temperature is computed to estimate the saturation distance of air. The complete analysis is made for two breathing cycles with different inhalation to exhalation ratios. The results indicate that decreasing the ventilation rate and increasing the respiration cycle can avoid the deep penetration of heat into the tract and consequently tissue thermal injury can be avoided. We have also explained numerically the role of mucus layer in avoiding tissue injury in intra-thoracic airways. We have also observed a significant difference in results for high ventilation rates between the cases of actual (cast replica) and regular airway geometry. The numerical results are in good adjustment with existing experimental data and thus validate our approach.

Use of Left Ventricular Assist Device After Arterial Switch Operation in Late Presenting D-Transposition of Great Arteries-A Technique for Retraining the Regressed Left Ventricle.

The preferred approach for patients with D-transposition of the great arteries with an intact ventricular septum (DTGA/IVS) is the arterial switch operation (ASO). In those patients presenting late, with regressed left ventricle (LV), successful LV preparation is of paramount importance to achieve this goal. We present a toddler with DTGA/IVS who underwent ASO followed by successful left ventricular retraining with postoperative left ventricular assist device support with CentriMag centrifugal pump.

Childhood obesity as a risk factor for bone fracture: a mechanistic study.

OBJECTIVE: To investigate the risk of bone fracture sustained by obese children exposed to falls. The bone fracture risk of obese children would be greater than that of their nonobese counterparts was hypothesized. DESIGN AND METHODS: Finite element-based computational models for children that reflected various levels of obesity by varying body mass and the thickness of the subcutaneous adipose tissue layer was developed. The models took account of both the momentum effect of variation of body mass and the cushion effect of variation of soft tissue thickness and examined these two contradictory effects on pelvic bone fracture risk through a set of sideways fall simulations with a range of impact speeds. RESULTS: The critical impact speed that yielded pelvic bone fracture decreased as the levels of obesity increased, which meant that the momentum effect of a greater body mass took precedence over the cushion effect of the soft tissue layer. CONCLUSIONS: The result suggests that obese children have a greater risk of pelvic bone fracture than do their nonobese counterparts in sideways falls. A further implication is that current child safety devices, systems, and regulations will need to be revisited as the prevalence of child obesity increases.

Patient-Specific Geometry Modeling and Mesh Generation for Simulating Obstructive Sleep Apnea Syndrome Cases by Maxillomandibular Advancement.

The objective of this paper is the reconstruction of upper airway geometric models as hybrid meshes from clinically used Computed Tomography (CT) data sets in order to understand the dynamics and behaviors of the pre- and postoperative upper airway systems of Obstructive Sleep Apnea Syndrome (OSAS) patients by viscous Computational Fluid Dynamics (CFD) simulations. The selection criteria for OSAS cases studied are discussed because two reasonable pre- and postoperative upper airway models for CFD simulations may not be created for every case without a special protocol for CT scanning. The geometry extraction and manipulation methods are presented with technical barriers that must be overcome so that they can be used along with computational simulation software as a daily clinical evaluation tool. Eight cases are presented in this paper, and each case consists of pre- and postoperative configurations. The results of computational simulations of two cases are included in this paper as demonstration.

Finite element model development of a child pelvis with optimization-based material identification.

A finite element (FE) model of a 10-years-old child pelvis was developed and validated against experimental data from lateral impacts of pediatric pelves. The pelvic bone geometry was reconstructed from a set of computed tomography images, and a hexahedral mesh was generated using a new octree-based hexahedral meshing technique. Lateral impacts to the greater trochanter and iliac wing of the seated pelvis were simulated. Sensitivity analysis was conducted to identify material parameters that substantially affected the model response. An optimization-based material identification method was developed to obtain the most favorable material property set by minimizing differences in biomechanical responses between experimental and simulation results. This study represents a pilot effort in the development and validation of age-dependent musculoskeletal FE models for children, which may ultimately serve to evaluate injury mechanisms and means of protection for the pediatric population.