Patient-Specific Patch for an Intra-Atrial Rerouting Procedure Developed Through Surgical Simulation

Background: In pediatric cardiac surgery, an application of three-dimensional (3D) modeling to develop custom-made prostheses is limited, and currently surgeons use their intraoperative visual estimation to develop 3D complex structures from 2D patch materials. Contemporary 3D designers are developing complex surfaces using surface modeling in other industries, which can be applied to pediatric cardiac surgery. However, its free-form nature may lead to intradesigner variability. Methods: A patient with a body weight of 4 kg with partial anomalous pulmonary venous connection and preoperative computed tomography data was selected, and a patient-specific 3D heart model was obtained. Through collaboration with a pediatric cardiologist and a pediatric cardiac surgeon, a 3D designer developed two patient-specific 3D patches for an intra-atrial rerouting procedure (IAR) for the patient using different methods of surface modeling. The shape and size of two flattened patches were analyzed using a geometric morphometrics (GM) approach. Computational fluid dynamics (CFD) analysis was also performed to calculate pressure drop across streamlines and flow energy loss in the right atrium for both patches. Results: The GM analysis showed that the size and shape of the two patches around the systemic vein orifice, crucial to prevent systemic venous obstruction, were almost equivalent. However, the CFD analysis showed that the pressure drop and flow energy loss were almost twice for one patch compared with the other. Conclusions: Our platform of developing a patient-specific 3D patch for an IAR procedure using surface modeling seemed promising, although intradesigner patch variability was not neglectable in our small-sized patient.

An Integrated and Automated Tool for Quantification of Biomechanics in Fetal and Neonatal Echocardiography

ObjectivesTo show simultaneous quantification of flow and mechanics of cardiac function from fetal and neonatal echocardiograms using an integrated set of automated, physics-based, echocardiography analysis methods.BackgroundQuantifying ventricular biomechanics from fetal and neonatal echocardiograms presents unique and significant challenges. Existing analysis tools are designed for adults and cannot accurately assess fetal subjects.MethodsWe used in-house developed analysis algorithms to quantify ventricular biomechanics from four-chamber B-mode and color Doppler routine examinations recordings for three hypoplastic left heart (HLHS) patients at 33-weeks’ gestation and first week post-birth along with age-matched controls. Chamber morphology, tissue motion, atrioventricular valve inflow, global longitudinal strain, and hemodynamic flow parameters were measured.ResultsPrenatal cardiac output differed between control (LV:157 ± 139 mL/min, RV:257 ± 218 mL/min) and HLHS subjects (410 ± 128 mL/min). This difference persisted for control (LV:233 ± 74 mL/min, RV:242 ± 140 mL/min) and HLHS subjects (637 ± 298 mL/min) after birth. Peak global longitudinal strain measurements did not differ in utero between control (LV: 12.2 ± 4.1%, RV:12.1 ± 4.9%) and HLHS subjects (RV:12.7± 4.2%). After birth, myocardial contraction increased for the control (LV:15.4 ± 2.8%, RV:22.9 ± 6.9%) and HLHS subjects (14.4 ± 6.2%). Postnatal early filling mitral flow velocity for the control subjects (LV:58.8 ± 17.6 cm/s) and early-filling tricuspid flow of the HLHS subjects (64.8 ± 23.7cm/s) were similar, while the late filling velocity decreased for the control subject LV (33.5 ± 8.1 cm/s) compared to the HLHS subjects (66.9 ± 23.0 cm/s). Importantly, flow energy loss in the fetal HLHS hearts was increased (0.35 ± 0.19 m3/s2) compared to the control subjects (LV:0.09 ± 0.07 m3/s2, RV:0.17 ± 0.12 m3/s2), and further increased postnatally for the HLHS subjects (0.55 ± 0.24 m3/s2) compared to the control subjects (LV:0.23 ± 0.20 m3/s2, RV:0.09 ± 0.06 m3/s2).ConclusionsWe demonstrate the feasibility of integrated quantitative measurements of fetal and neonatal ventricular hemodynamics and biomechanics using only four-chamber B-mode and color Doppler recordings.Short AbstractWe integrated novel echocardiogram analysis methods to quantify ventricular flow and mechanics using apical long-axis B-mode and color Doppler imaging from fetal and neonatal subjects. Three hypoplastic left heart patients (HLHS) imaged at 33-weeks gestation and again in the first postnatal week, along with age-matched controls, were evaluated. For the first time, we show quantified hemodynamics from fetal echocardiography using flow reconstruction, flow energy loss, and intraventricular pressure, as well as global strain and strain rate. These tools are capable of longitudinal analysis of ventricle maturation, flow dynamics, and quantified measurements from routine examinations of complex congenital heart disease.

Quantification of Energy Loss in Two Grated Inlets under Pressure

Grated inlets have the normal function of collecting the surface runoff into sewer networks, but when the flow exceeds the capacity of the sewer pipes and conduits get pressurized, an outflow from the sewer manholes and grates can occur. In this case, the grate produces an energy loss in the outflow from sewer to street that could be hydraulically quantified characterizing this kind of flow. Energy loss analysis in trash racks can be found in technical literature, but no specific studies on sewer grate inlets have been found. For this reason, some experiments in full scale were developed in the hydraulic laboratory of the Technical University of Catalonia (UPC) in order to quantify hydraulic energy losses associated with flow through grated inlets during surcharging conditions. The main goal of this research work was to experimentally quantify the values of the local loss coefficient k for two different surcharged real scale grated inlets existing in Barcelona. For the tested overflows between 20 and 50 L/s, a range from 0.25 to 3.41 was observed for k coefficients under different average velocities of reference and different flow conditions.

P1495Energy loss by right ventricular pacing: normal left ventricular function vs. hypertrophic cardiomyopathy

Background Right ventricular (RV) pacing causes left ventricular (LV) dysfunction. On the other hand, RV pacing for hypertrophic obstructive cardiomyopathy (HOCM) is an established treatment. LV flow energy loss (EL) is a new hemodynamic index for assessing cardiac function. However, the impact of RV pacing on EL remains unknown. Objective The objective of this study was to investigate the EL by RV pacing on normal LV function and hypertrophic cardiomyopathy (HCM). Methods A total of 28 patients underwent echocardiography for EL assessment under AAI (without RV pacing) and DDD (with all RV pacing) mode. Among them, 16 were sick sinus syndrome (SSS) patients with normal LV function, and 12 were HCM patients. EL was calculated from color Doppler images using a vector flow mapping. Results There were no significant difference in patients' background parameters between the SSS and the HCM groups. In the SSS group, mean systolic EL was significantly increased from AAI to DDD mode (14.9 to 19.2 mW/m, P<0.01, Panel A), whereas diastolic EL was not changed from AAI to DDD mode (22.3 to 18.8 mW/m, P=0.12). In the HCM group, systolic mean EL was significantly decreased from AAI to DDD mode (29.9 to 22.5 mW/m, P<0.01, Panel B) irrespectively of with or without LV outflow obstruction, whereas diastolic mean EL was not changed from AAI to DDD mode (28.6 to 24.3 mW/m, P=0.47). Change of flow energy loss Conclusion RV pacing increased mean systolic EL in normal LV function, but decreased in HCM with or without LV outflow obstruction. In the patients with HCM, the impact of RV pacing on EL is different compared with normal LV function.

The Design of New Water Jet Spray Gun

The structure design of gun according to the flow velocity and flow energy loss of the fluid in water cutting gun jet channel. Take the gun body plus filter method to solve when the water knife nozzle is small that easy jams. Adopt replaceable type jet tube solve appear jams when cannot promptly eliminate malfunction. Use adjustable grip handle solve the different length require in different surgery. Adopt casing tube wall approach to solving the negative pressure attract residual tissues and cells is not easy cleared.