In vitro hemodynamic performance of a blood pump for self-powered venous assist in univentricular hearts
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ABSTRACT:
SUBMITTER: Rasooli R
PROVIDER: S-EPMC10960831 | biostudies-literature | 2024 Jan
REPOSITORIES: biostudies-literature
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Project description:PurposeThe Fontan circulation carries a dismal prognosis in the long term due to its peculiar physiology and lack of a subpulmonic ventricle. Although it is multifactorial, elevated IVC pressure is accepted to be the primary cause of Fontan's high mortality and morbidity. This study presents a self-powered venous ejector pump (VEP) that can be used to lower the high IVC venous pressure in single-ventricle patients.MethodsA self-powered venous assist device that exploits the high-energy aortic flow to lower IVC pressure is designed. The proposed design is clinically feasible, simple in structure, and is powered intracorporeally. The device's performance in reducing IVC pressure is assessed by conducting comprehensive computational fluid dynamics simulations in idealized total cavopulmonary connections with different offsets. The device was finally applied to complex 3D reconstructed patient-specific TCPC models to validate its performance.ResultsThe assist device provided a significant IVC pressure drop of more than 3.2 mm Hg in both idealized and patient-specific geometries, while maintaining a high systemic oxygen saturation of more than 90%. The simulations revealed no significant caval pressure rise (< 0.1 mm Hg) and sufficient systemic oxygen saturation (> 84%) in the event of device failure, demonstrating its fail-safe feature.ConclusionsA self-powered venous assist with promising in silico performance in improving Fontan hemodynamics is proposed. Due to its passive nature, the device has the potential to provide palliation for the growing population of patients with failing Fontan.
| S-EPMC10412470 | biostudies-literature
Project description:Left ventricular assist devices (LVAD) provide a durable option for patients with advanced hear failure. Axial and centrifugal pump physiology differs with regard to the relationship between pump inflow-outflow cannula pressure differential and flow, which results in device behavior that can vary drastically under different loading conditions. Ramp studies can aid the clinician in choosing the optimal speed to adequately unload the left ventricle. Advances in 3-dimensional echocardiography enhance the understanding of chamber geometry for both types of LVADs. Novel outflow graft imaging techniques have been developed to better characterize aortic insufficiency, which may be underestimated with current standard methods.
| S-EPMC6252051 | biostudies-other
Project description:Soft pumps have the potential to transform industries including soft robotics, wearable devices, microfluidics and biomedical devices, but their efficiency and power supply limitations hinder prolonged operation. Here, we report a self-powered triboelectric-electrohydrodynamic pump, which combines a soft electrohydrodynamic pump driven by an electrostatic generator, specifically a triboelectric nanogenerator. The triboelectric nanogenerator collects ambient energy and converts it into high-voltage power source, allowing it to self-power an electrohydrodynamic pump and thus eliminating the need for external power supply. Using power management circuit, geometric shape optimization, and stacking methods, we achieve a maximum pressure of 4.49 kPa and a maximum flow rate of 502 mL/min. We demonstrate the pump's versatility in applications such as self-powered soft actuators, oil pumping in microfluidics, and oil purification. The triboelectric-electrohydrodynamic pump holds promising applications, and offers new insights for the development of fully self-powered systems.
| S-EPMC11790962 | biostudies-literature
Project description:BackgroundPalliative repair of single ventricle defects involve a series of open-heart surgeries where a single-ventricle (Fontan) circulation is established. As the patient ages, this paradoxical circulation gradually fails, because of its high venous pressure levels. Reversal of the Fontan paradox requires an extra subpulmonic energy that can be provided through mechanical assist devices. The objective of this study was to evaluate the hemodynamic performance of a totally implantable integrated aortic-turbine venous-assist (iATVA) system, which does not need an external drive power and maintains low venous pressure chronically, for the Fontan circulation.MethodsBlade designs of the co-rotating turbine and pump impellers were developed and 3 prototypes were manufactured. After verifying the single-ventricle physiology at a pulsatile in vitro circuit, the hemodynamic performance of the iATVA system was measured for pediatric and adult physiology, varying the aortic steal percentage and circuit configurations. The iATVA system was also tested at clinical off-design scenarios.ResultsThe prototype iATVA devices operate at approximately 800 revolutions per minute and extract up to 10% systemic blood from the aorta to use this hydrodynamic energy to drive a blood turbine, which in turn drives a mixed-flow venous pump passively. By transferring part of the available energy from the single-ventricle outlet to the venous side, the iATVA system is able to generate up to approximately 5 mm Hg venous recovery while supplying the entire caval flow.ConclusionsOur experiments show that a totally implantable iATVA system is feasible, which will eliminate the need for external power for Fontan mechanical venous assist and combat gradual postoperative venous remodeling and Fontan failure.
| S-EPMC6021195 | biostudies-literature
Project description:BackgroundIn patients with left heart failure, micro-RNAs (miRNAs) have been shown to be of diagnostic and prognostic value. The present study aims to identify those miRNAs in patients with univentricular heart (UVH) disease that may be associated with overt heart failure.MethodsA large panel of human miRNA arrays were used to determine miRNA expression profiles in the blood of 48 UVH patients and 32 healthy controls. For further selection, the most abundantly expressed miRNA arrays were related to clinical measures of heart failure and selected miRNAs validated by polymerase chain reaction were used for the prediction of overt heart failure and all-cause mortality.ResultsAccording to microarray analysis, 50 miRNAs were found to be significantly abundant in UVH patients of which miR-150-5p was best related to heart failure parameters. According to ROC analysis, NT-proBNP levels (AUC 0.940, 95% CI 0.873-1.000; p = 0.001), miR-150-5p (AUC 0.905, 95% CI 0.779-1.000; p = 0.001) and a higher NYHA class ≥ III (AUC 0.893, 95% CI 0.713-1.000; p = 0.002) were the 3 most significant predictors of overt heart failure. Using a combined biomarker model, AUC increased to 0.980 indicating an additive value of miR-150-5p. Moreover, in the multivariate analysis, a higher NYHA class ≥ III (p = 0.005) and miR-150-5p (p = 0.006) turned out to be independent predictors of overt heart failure.ConclusionIn patients with UVH, miR-150-5p is an independent predictor of overt heart failure and thus may be used in the risk assessment of these patients.
| S-EPMC6786722 | biostudies-literature
Project description:Polytetrafluoroethylene (PTFE) is a fascinating electret material widely used for energy harvesting and sensing, and an enhancement in the performance could be expected by reducing its size into nanoscale because of a higher surface charge density attained. Hence, the present study demonstrates the use of nanofibrous PTFE for high-performance self-powered wearable sensors. The nanofibrous PTFE is fabricated by electrospinning with a suspension of PTFE particles in dilute polyethylene oxide (PEO) aqueous solution, followed by a thermal treatment at 350 °C to remove the PEO component from the electrospun PTFE-PEO nanofibers. The obtained PTFE nanofibrous membrane exhibits good air permeability with pressure drop comparable to face masks, excellent mechanical property with tensile strength of 3.8 MPa, and stable surface potential of - 270 V. By simply sandwiching the PTFE nanofibrous membrane into two pieces of conducting carbon clothes, a breathable, flexible, and high-performance nanogenerator (NG) device with a peak power of 56.25 μW is constructed. Remarkably, this NG device can be directly used as a wearable self-powered sensor for detecting body motion and physiological signals. Small elbow joint bending of 30°, the rhythm of respiration, and typical cardiac cycle are clearly recorded by the output waveform of the NG device. This study demonstrates the use of electrospun PTFE nanofibrous membrane for the construction of high-performance self-powered wearable sensors.
| S-EPMC6658626 | biostudies-literature
Project description:BackgroundWe recently demonstrated that a novel intra-ventricular membrane pump (IVMP) was able to increase the pump function of isolated beating porcine hearts. In follow-up, we now investigated the impact of the IVMP on myocardial oxygen consumption and total mechanical efficiency (TME) and assessed the effect of IVMP-support in acutely failing hearts.MethodsIn 10 ex vivo beating porcine hearts, we studied hemodynamic parameters, as well as arterial and coronary venous oxygen content. We assessed cardiac power (CP), myocardial oxygen consumption (MVO2), and TME (CP divided by MVO2) under baseline conditions and during IVMP-support. Additionally, five isolated hearts were subjected to global hypoxia to investigate the effects of IVMP-support on CP under conditions of acute heart failure.ResultsUnder physiological conditions, baseline CP was 0.36 ± 0.10 W, which increased to 0.65 ± 0.16 W during IVMP-support (increase of 85% ± 24, p < 0.001). This was accompanied by an increase in MVO2 from 18.6 ± 6.2 ml/min at baseline, to 22.3 ± 5.0 ml/min during IVMP-support (+26 ± 31%, p = 0.005). As a result, TME (%) increased from 5.9 ± 1.2 to 8.8 ± 1.8 (50 ± 22% increase, p < 0.001). Acute hypoxia-induced cardiac pump failure reduced CP by 35 ± 6%, which was fully restored to baseline levels during IVMP-support in all hearts.ConclusionIVMP-support improved mechanical efficiency under physiological conditions, as the marked increase in cardiac performance only resulted in a modest increase in oxygen consumption. Moreover, the IVMP rapidly restored cardiac performance under conditions of acute pump failure. These observations warrant further study, to evaluate the effects of IVMP-support in in vivo animal models of acute cardiac pump failure.
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Project description: Not available
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Project description:Two-dimensional (2D) layered organic-inorganic hybrid perovskites have attracted wide attention in high-performance optoelectronic applications due to their good stability and excellent optoelectronic properties. Here, a high-performance self-powered photodetector is realized based on an asymmetrical metal-semiconductor-metal (MSM) device structure (Pt-(PEA)2PbI4 SC-Ag), which introduces a strong built-in electric field by regulating interface Schottky barriers. Benefitting from excellent built-in electrical potential, the photodetector shows attractive photovoltaic properties without any power supply, including high photo-responsivity (114.07 mA W-1), fast response time (1.2 μs/582 μs) and high detectivity (4.56 × 1012 Jones). Furthermore, it exhibits high-fidelity imaging capability at zero bias voltage. In addition, the photodetectors show excellent stability by maintaining 99.4% of the initial responsivity in air after 84 days. This work enables a significant advance in perovskite SC photodetectors for developing stable and high-performance devices.
| S-EPMC9465635 | biostudies-literature
Project description:Certain aquatic insects rapidly traverse water by secreting surfactants that exploit the Marangoni effect, inspiring the development of many self-propulsion systems. In this research, to demonstrate a new way of delivering liquid fuel to a water surface for Marangoni propulsion, a microfluidic pump driven by the flow-imbibition by a porous medium was integrated to create a novel self-propelling robot. After triggered by a small magnet, the liquid fuel stored in a microchannel is autonomously transported to an outlet in a mechanically tunable manner. We also comprehensively analyzed the effects of various design parameters on the robot's locomotory behavior. It was shown that the traveled distance, energy density of fuel, operation time, and motion directionality were tunable by adjusting porous media, nozzle diameter, keel-extrusion, and the distance between the nozzle and water surface. The utilization of a microfluidic device in bioinspired robot is expected to bring out new possibilities in future development of self-propulsion system.
| S-EPMC8410760 | biostudies-literature