Blood Pump Research Articles

The heart is the body’s core pump. Heart failure impairs the heart’s ability to pump blood, leading to circulatory disorders. The artificial heart (blood pump) is an important mechanical circulatory support device that can partially or completely substitute cardiac pumping function, potentially improving hemodynamic performance and alleviating symptoms of heart failure. A combination of computational fluid dynamics simulation and hydraulic performance testing was used to study key parameters of the impeller, including blade count, blade wrap angle, impeller flow path, and diversion cone height. The goal was to reduce hemolysis risk and enhance pumping efficiency. Increasing the blade count raised the head, with optimal efficiency achieved at seven blades. A larger blade wrap angle decreased the head but improved efficiency. Synchronizing the flow path and diversion cone height at 4.1 mm maximized the head. Under various rotational speeds, the studied hemolysis index remained well below 0.1 g/100 L. Both experimental and simulation data were validated against each other, meeting the required error tolerances. The studied blood pump meets the design specifications. At an operating condition of 5 L/min flow rate and 2800 rpm, the pump achieves the required head and hemolysis criteria with a margin of safety.

Could toy hearts possibly work as well as a real heart? To find out, we purchased six toy hearts, ranging from a spooky Halloween beating heart to a colorful plush heart. Our guess was that toy hearts would not work as well as a real human heart! We tested the toys in our laboratory using the exact same tools and methods we use for testing real hearts and mechanical blood pumps. We looked at flow, pressure, volume, and how well the toy heart pumped water. We also asked three heart surgeons to judge each toy heart based on how real they looked and what features they liked. As expected, the toy hearts were not realistic and could not pump as well as a real heart. This article combines human health and engineering as a fun and silly scientific question. Our hope is that readers will find it educational and entertaining!

Abstract Background and Aims Hemodialysis (HD) is a life sustaining treatment for patients with end-stage renal failure, and ongoing efforts aim to enhance both its efficiency and safety. In terms of safety, the precautionary principle has been applied. The quality of the water used in dialysis and the biocompatibility of dialysis filters has been significantly improved, while prevention of air contamination of the bloodline lacks behind. Dialysis machines are equipped with air detectors that shall trigger alarms if larger amounts of air enter the venous side. However, air bubbles larger than 500 µm diameter can bypass these detectors without activating alarms. Air is foreign to the bloodstream and contains inert gases, which can cause severe complications such as emboli and tissue damage, confirmed by case reports and autopsy studies. No data exist of the air volumes contaminating the blood during regular HD and difference in air elimination. The objective of this interventional clinical study was to ascertain whether the elimination of air entering the patients can be more efficacious. Method Twenty chronic HD patients participated in a randomized cross-over study comparing the Emboless® and F5008 venous chambers. Each patient underwent four dialysis sessions divided into two paired series, resulting in 80 analysed sessions. The same dialyzers, blood pump speeds, HD settings, and ultrafiltration parameters were used within each pair. The cumulative volumes of air bubbles (>20 µm in diameter) were measured at the inlet and outlet line of each venous chamber using an adapted ultrasound device (BCC200, GAMPT). The measurement duration was 30 minutes, extended if fewer than 1000 detections were recorded at the Inlet. The percentage of air volume passing through the venous chamber and reaching the patient was calculated (Mann–Whitney U-test). Results The median air Inlet volume of 80 dialyses was 20.5 µL (IQR 12.2–38.4 µL), with no significant difference in air inflow between the two venous chambers. The median proportion of volumes of air leakage passing to the patient was lower with the Emboless® (8.7%) compared to the F5008 chamber (25.9%) (P < 0.001, Fig. 1). Conclusion The Emboless® venous chamber is the preferred choice for minimizing potentially harmful air contamination during hemodialysis. Air leakage to patients was reduced to one-third when using the Emboless® compared to the F5008 venous chamber, making it a safer option for clinical use.

Significant advances have been made in the design and manufacture of artificial blood pumps. However, blood compatibility issues such as hemolysis, thrombosis, and inflammation during the clinical use of artificial blood pumps have reduced their reliability. Among these issues, hemolysis problems can lead to acute kidney injury, hyperkalemia, and in severe cases, even serious threats to life. To address hemolysis problems, blood transfusion, reduction of blood pump speed, and medication to promote erythropoiesis are generally used. This study explores the hemolysis problem from the perspective of the essence of problem solving, that is, the design of the blood pump structure. A new centrifugal pump UJN-1 was designed based on empirical design theory and the velocity coefficient method of traditional centrifugal pumps. We used the commercial software Fluent to compare the data obtained from our simulation of FDA benchmark blood pumps with the results of other researchers to validate the accuracy of our simulation method. Based on the CFD numerical simulation method, we evaluated the hemolytic performance of three centrifugal pumps: Revolution, PuraLev 200SU, and UJN-1. The hydraulic performance of the designed UJN-1 blood pump was experimentally verified. The UJN-1 could provide a blood flow rate of 4-6 L/min and a blood pressure of 120 mmHg at 2500 rpm. The CFD numerical simulation and experimental results of the designed artificial blood pump UJN-1 were compared and verified, and the results showed that the error was small. The hemolysis results of the Revolution pump, 200SU pump, and UJN-1 pump were 3.35 × 10-4%, 2.20 × 10-4%, and 1.49 × 10-4%, respectively. In a comparison of hemolysis among the three pumps, the UJN-1 pump had the lowest level of hemolysis. This low hemolysis artificial blood pump design is important for long-term clinical use and high reliability of medical devices.

Heart failure is a clinical syndrome caused by any structural or functional cardiac disorder that impairs the heart's ability to function efficiently and pump blood around the body. Function can also be monitored using cardiac implantable electronic devices, some of which may also deliver a therapeutic benefit (e.g. pacemakers), while others only monitor metrics over time. Implantable devices can include algorithms that aim to predict the occurrence of a heart failure event. They are intended to be used alongside clinical judgement and make treatment decisions. To determine the clinical and cost-effectiveness of the four remote monitoring algorithms (CorVue, HeartInsight, HeartLogic and TriageHF) for detecting heart failure in people with cardiac implantable electronic devices. We performed systematic reviews of clinical, cost-effectiveness, quality of life and cost outcomes. We searched MEDLINE and other sources of published and unpublished literature, including manufacturers' websites and Clinical Trials Registries between June and August 2023. For the clinical effectiveness review, study selection was completed by two independent reviewers at both title and abstract, and full-text screening stages. Data extraction and study quality appraisal were completed by a single reviewer and checked for accuracy by a second. Due to heterogeneity, no statistical analyses were performed, and a narrative synthesis was reported. A de novo two-state Markov model (with alive and dead states) was used to estimate the cost-effectiveness of algorithm-based remote monitoring of heart failure risk data in people with cardiac implantable electronic devices over a lifetime. There was reasonable evidence to suggest HeartLogic and TriageHF can accurately predict heart failure events. CorVue's prognostic accuracy is less clear due to high heterogeneity in findings between studies. There was only a single published HeartInsight study, which suggested similar accuracy to the other algorithms. Cost-effectiveness estimates could only be produced for HeartLogic and TriageHF, which were less costly and more effective compared to the respective cardiac implantable electronic device without the algorithms. For all technologies, only a small reduction in hospitalisation rates were required for them to be cost-effective. The evidence for each algorithm was limited in terms of comparative evidence. Additionally, available evidence was often of low quality. The comparative outcome evidence for economic model was very limited. There was a lack of comparative evidence across all technologies included in the scope. Evidence for HeartLogic and TriageHF suggests that they may have acceptable prognostic accuracy for predicting heart failure events. However, further evidence is required to confirm these results. Specifically, further comparative evidence (e.g. randomised controlled trials) is required to show the benefit of the algorithms compared to standard practice in intermediate and clinical outcomes. For example, some studies suggested high false positive rates and low sensitivity. Only a single published study was identified for HeartInsight, therefore there are insufficient data to draw conclusions on prognostic accuracy and the benefits on clinical and intermediate outcomes. It is likely remote monitoring systems for CorVue, HeartInsight, HeartLogic and TriageHF would be cost-effective were they to result in fewer hospitalisations in heart failure patients; however, in general, this may apply to any device lowering the hospital visit. In addition, any potential benefits of reduced hospitalisation need to be carefully balanced with chances of overtreatment resulting from alerts. Prospective studies on effectiveness of remote monitoring as well as consideration of patient voice and preferences would facilitate a more complete evaluation of technology benefits. This study is registered as PROSPERO CRD42023447089. This award was funded by the National Institute for Health and Care Research (NIHR) Evidence Synthesis programme (NIHR award ref: NIHR135894) and is published in full in Health Technology Assessment; Vol. 29, No. 50. See the NIHR Funding and Awards website for further award information.

Operating conditions significantly influence hemolysis generation in rotodynamic blood pumps (RBPs). Previous experiments conducted under constant operating conditions have demonstrated that lower flow rates are associated with a higher normalized index of hemolysis (NIH). However, in clinical scenarios, the pump flow rate fluctuates in response to the residual cardiac function. This study aims to investigate the effects of various pulsatile operating conditions on hemolysis generation and von Willebrand Factor (vWF) degradation of RBP. To investigate these conditions, pulsatile flow experiments were conducted for 12 hours using HeartMate 3 (HM3, Abbott Inc, USA) in a hybrid mock circulatory loop with citrated human blood from hemochromatosis patients. Three operating conditions (high, low, and no residual cardiac function) were examined under two pump speed settings: normal (5400 rpm, 4.3 L/min) and low (4800 rpm, 2.5 L/min). Hemolysis was assessed by measuring delta free hemoglobin every 30 minutes (dfHb30 min) and calculating NIH. High molecular weight (HMW) vWF multimer degradation was assessed using immunoblotting. There was no significant difference in dfHb30 min (p>0.388), NIH (p > 0.382), and HMW vWF multimers degradation (p > 0.364) between the three operating conditions, but differences in these parameters were observed between the normal and low speed settings. Meanwhile, a consistent trend in the hemolysis outcomes was observed with slightly elevated hemolysis in no and high pulsatility conditions of both speed settings. Hemocompatibility of the HM3 is not significantly affected by periodic high/low flow or backflows through the pump in in-vitro evaluation but rather by the pump operating condition: flow rate and pump speed.

The effects of non-physiological shear rate gradient, frequency, and amplitude on platelet aggregation.

The paper presents a new fully parametric geometrical model of a ventricular assist device (VAD) together with an example of a comprehensive automated workflow integrating multidisciplinary tools for geometrical design, fluid dynamic assessment, and automated shape optimisation. Advanced geometrical constructions are applied to develop a new fully parametric CAD (Computer Aided Design) model that generates a stable, watertight geometry of an axial blood pump in both non-uniform B-spline representation and node-to-node triangular mesh. The presented example of a fully integrated simulation workflow that combines open-source software tools within a user-friendly environment, demonstrates its efficiency while benefiting from the fully parametric, easily adjustable VAD model. The proposed geometrical modelling and numerical simulation approach offers a seamless, ready-to-use test case for computer aided design, analysis and optimisation of VADs. The shown results demonstrate the essential advantages of the parametric modelling approach, showcasing its potential application in performance improvements of an axial blood pump through shape optimisation. Overall, the paper highlights the viability of automated, multidisciplinary design workflows in biomedical engineering.

Epigenetics of mitochondrial and inflammation in cardiac fibrosis.

The design and development of ventricular assist devices have heavily relied on computational tools, particularly computational fluid dynamics (CFD), since the early 2000s. However, traditional CFD-based optimization requires costly trial-and-error approaches involving multiple design cycles. This study aims to propose a more efficient VAD design and optimization framework that overcomes these limitations. We developed a system- and component-level ventricle assist device optimization approach by coupling a lumped parameter cardiovascular physiology model with parametric turbomachinery, volute design, and blade path generation packages. The framework incorporates pump hydrodynamic losses and is validated against experimental data from six distinct blood pump designs and CFD simulations. The optimization framework allows for the specification of both physiology-related and device-related objective functions to generate optimized blood pump configurations over a large parameter space. The optimization was applied to the U.S. Food and Drug Administration (FDA) benchmark blood pump as the baseline design. Results showed that an optimized FDA pump, maintaining the same cardiac output and aortic pressure, achieved a ~ 32% reduction in blade tip velocity compared to the baseline, resulting in an ~ 88% reduction in hemolysis. Additionally, an alternative design with a 40% reduction in blood-wetted area was generated while preserving the baseline pressure and flow. The proposed optimization framework improves device developmentefficiency by shortening the design cycle and enabling hydrodynamically optimized pumps that perform well across diverse patient hemodynamics. The optimized pump designs are available as open-source resources for further research and development.

Long-lasting stability of the anticoagulant coating on centrifugal blood pumps (CBPs) is of vital importance to ensure the hemocompatibility of the blood circulation system therein. Heparin coatings are often prepared using static wet chemical technique, but these face risks of delamination or deactivation induced by blood flow. Inspired by the flow-shear-stress mediated conformation changes of von Willebrand factor, a novel fluid-driven deposition technique was employed to apply polydopamine-heparin coatings within CBPs. Moreover, most FDA-approved CBPs are designed for high-flow-rate CBPs of major organs like the heart and lungs (1000∼8000 ml/min). Few are tailored for low-flow-rate perfusion of other organs such as the liver, kidney and brain (<50–300 mL/min). Our approach addresses this gap by developing low-flow-rate CBPs through anti-thrombogenic coatings and anti-hemolytic structural optimizations. In this study, we introduced an axial magnetic direct drive motor with our optimized low-flow-rate CBPs, achieving a stable-low-flow-rate rate ranging from 16.3 mL/min (300 rpm) to 121.0 mL/min (2000 rpm). The resulting CBPs system exhibited enhanced flow stability and hemocompatibility in rabbit model experiments, demonstrating significantly lower hemolysis rates and lower thrombus formation risks. These results indicate that the polydopamine-assisted heparin coating provides short-term stability under dynamic flow, offering a promising strategy for low-flow-rate CBPs, though its long-term durability and clinical translation potential require further validation.

Research on Fluid Dynamics Optimization of a Fully Hydrodynamic Centrifugal Blood Pump

To assess hemolysis potential, blood pump developers frequently perform invitro testing in accordance with the ASTM F1841 standard. However, options in test parameters such as blood species, anticoagulant, and blood collection and preparation methods can lead to inconsistent hemolysis results. To improve invitro hemolysis test sensitivity and characterize the impact of species and hematocrit (HCT) on flow-induced hemolysis, a pressure-driven, single-pass micro-nozzle test system with short blood exposure times was developed. To compare different blood species, porcine, bovine, ovine, and human blood pools were adjusted to 35% HCT, and 2.7 mL blood aliquots were pneumatically injected at different flow rates through two converging nozzle tips with diameters of 250 and 410 μm. Plasma-free hemoglobin (pfHb) concentration was measured to assess hemolysis after passing through the nozzle tip model. Additionally, porcine blood was tested at 25%, 35%, and 45% HCT using the 410 μm nozzle. Using a single blood source, the repeatability for a single nozzle and reproducibility based on five separate nozzles were characterized. Results for the nozzles were consistent, with coefficients of variation of 0.5% for flow rate and less than 16% for pfHb levels. Hemolysis increased markedly with flow rate for all species, with pfHb levels being lowest for ovine and bovine blood and highest for human blood. Additionally, hemolysis increased non-linearly with increasing HCT. The nozzle tip model can be used to examine other blood factors that impact hemolysis and to support and advance computational fluid dynamics hemolysis simulations.

Machine learning algorithms for heart disease diagnosis: A systematic review.

Extracorporeal membrane oxygenation (ECMO) is a powerful treatment for patients with severe heart and lung failure. However, bleeding, thrombosis, and hemolysis are three common clinical complications that limit the application of ECMO. The high rotational speed of the centrifugal blood pump in an ECMO device can cause significant damage to red blood cells. Therefore, calculation and prediction of this damage are essential to evaluate ECMO devices and the associated pathological hemodynamics. In this study, the internal flow and hemolysis rate of an ECMO centrifugal blood pump are analyzed by computational fluid dynamics simulations. Using the discrete phase method, the damage to red blood cells caused by wall shear stress is investigated under clinical working condition of a centrifugal blood pump, and the hemolysis index of the pump is systematically evaluated to be 1.3%. It is found that the pump impeller is the main factor contributing to hemolysis, accounting for 84% of the total in the pump. The systematic evaluation of hemolysis in an ECMO centrifugal blood pump presented here will help provide theoretical support for risk assessment of ECMO systems in clinical application.

Critical appraisal of Zhu et al.'s magnetic drive blood pump: Toward clinical translation.

Cardiovascular diseases are the heart-related illnesses. If not treated, that often turns into serious and complex conditions that often result in the death of an individual. It is one of the top causes of death globally. The heart pumps blood throughout the body. This research focuses on predictive analysis and the determination of the severity of heart disease using machine learning algorithms. The datasets are selected then feature selection is the major step of preprocessing, which involves mechanisms to use impactful columns of the data set for experiments. Feature selection techniques include technical methods like the Pearson Correlation Coefficient, Relief, Minimum Redundancy Maximum Relevance, and Least Absolute Shrinkage and Selection Operator. Any of them generate results based on high relevancy and information gain. Choosing relevant features,due to the existence of labeled data, the classification technique is ideal. The supervised learning algorithms are applicable for this prospective. There also exists a proposed ensemble method algorithm. This approach results in an accuracy of 94.74%. The research is significant since it is helpful to determine early heart disease detection, which is an important aspect of early disease detection, which may save lives by early diagnosis in the future.

Cardiovascular diseases remain a leading cause of mortality worldwide, making blood pumps or Ventricular Assist Devices essential in cardiac care. In this study, a bespoke motorpump system was designed, and by optimizing the impeller geometry across fifteen design parameters, hydraulic efficiency was enhanced while hemolysis risk was reduced. A set of 290 simulations was performed using a Design of Experiments approach, leading to the development of advanced Response Surface Models via Kriging and Genetic Aggregation. Subsequently, a Multi-Objective Genetic Algorithm was employed to maximize outlet pressure and minimize shear stress simultaneously. Among these methods, Genetic Aggregation ultimately outperformed Kriging in the final optimization phase, achieving an 11% increase in outlet pressure and a 23% reduction in mean scalar shear stress relative to the baseline. Our findings underscore the importance of managing multiple geometric factors concurrently for substantial improvements in pump performance. Building on these optimized hydraulic conditions, we introduced a magnetically levitated motor that integrates seamlessly with the pump, dispensing with mechanical bearings. The rotor remains stably suspended by hydrodynamic and magnetic forces, reducing frictional losses and prolonging the device's lifespan. This magnetically-levitated design eliminates bearings and lowers friction, suiting medical and pharmaceutical uses.

Congestive heart failure (CHF) is a critical condition resulting from impaired blood pumping, leading to fluid accumulation. While calcium plays a vital role in skeletal health and muscle contraction, its potential in preventing CHF remains unclear. This study aimed to investigate the relationship between calcium intake and the risk of CHF using data from the National Health and Nutrition Examination Survey (NHANES) collected between 2003 and 2018. After completing the questionnaire, participants were classified into CHF and control groups, with calcium intake considered as the primary exposure variable, alongside categorical factors such as age and race. Statistical analyses included t-tests and chi-square tests. A subsequent risk stratification analysis assessed the impact of various covariates on CHF. Additionally, Least Absolute Shrinkage and Selection Operator (LASSO) regression was applied to identify optimal predictor variables, and model performance was evaluated using the receiver operating characteristic curve. A total of 3,083 participants were included in the study. Baseline characteristics revealed significant differences in race (p = 0.004), education (p = 0.019), fasting glucose (p = 0.047), and calcium intake (p = 0.020) between the CHF and control groups. In model 3, calcium intake was significantly associated with a reduced risk of CHF (p < 0.001, OR = 6.37 × 10-4, 95% CI = 1.47 × 10-4 - 1.13 × 10-3), acting as a protective factor (OR < 1, 95% CI = 1 × 10-6 - 1 × 10-5). LASSO regression further identified calcium intake as a predictor variable. Calcium intake serves as a protective factor against CHF, potentially lowering its risk. These findings provide theoretical support for the prevention and diagnosis of CHF.

Blood compatibility, defined as a material's ability to maintain blood flow without inducing coagulation or hemolysis, was investigated through surface roughness optimization in blood pump flow channels. This study examines how machining parameters (depth of cut, cutting speed, feed per tooth, and cutting width) affect surface roughness using orthogonal experiments, revealing their descending order of influence. Blood compatibility tests comparing cellular damage and adhesion across varying surface roughness levels demonstrated that rougher titanium alloy surfaces significantly increased hemolysis rates and promoted platelet adhesion, accelerating thrombus formation. Genetic algorithm optimization identified optimal parameters: 80 m/min cutting speed, 0.2 mm depth of cut, 1.25 mm cutting width, and 0.02 mm/tooth feed. These parameters minimize surface roughness while maintaining machining efficiency, crucially enhancing blood pump performance by reducing thrombogenic risks. The established evaluation system and parameter optimization methodology provide practical guidance for manufacturing blood-contacting medical devices with improved hemocompatibility.