Flow characteristics and hemolytic performance of the new Breethe centrifugal blood pump in comparison with the CentriMag and Rotaflow pumps

Blood pumps have been increasingly used in mechanically assisted circulation for ventricular assistance and extracorporeal membrane oxygenation support or during cardiopulmonary bypass for cardiac surgery. However, there have always been common complications such as thrombosis, hemolysis, bleeding, and infection associated with current blood pumps in patients. The development of more biocompatible blood pumps still prevails during the past decades. As one of those newly developed pumps, the Breethe pump is a novel extracorporeal centrifugal blood pump with a hybrid magnetic and mechanical bearing with attempt to reduce device-induced blood trauma. To characterize the hydrodynamic and hemolytic performances of this novel pump and demonstrate its superior biocompatibility, we use a combined computational and experimental approach to compare the Breethe pump with the CentriMag and Rotaflow pumps in terms of flow features and hemolysis under an operating condition relevant to ECMO support (flow: 5 L/min, pressure head: ~350 mmHg). The computational results showed that the Breethe pump has a smaller area-averaged wall shear stress (WSS), a smaller volume with a scalar shear stress (SSS) level greater than 100 Pa and a lower device-generated hemolysis index compared to the CentriMag and Rotaflow pumps. The comparison of the calculated residence times among the three pumps indicated that the Breethe pump might have better washout. The experimental data from the in vitro hemolysis testing demonstrated that the Breethe pump has the lowest normalized hemolysis index (NIH) than the CentriMag and Rotaflow pumps. It can be concluded based on both the computational and experimental data that the Breethe pump is a viable pump for clinical use and it has better biocompatibility compared to the clinically accepted pumps.

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Impeller (straight blade) design variations and their influence on the performance of a centrifugal blood pump

The International Journal of Artificial Organs ◽

10.1177/0391398820913559 ◽

2020 ◽

Vol 43 (12) ◽

pp. 782-795

Author(s):

Peng Fang ◽

Jianjun Du ◽

Shunzhou Yu

Keyword(s):

Shear Stress ◽

Pressure Head ◽

Radial Force ◽

Small Scale ◽

Blade Angle ◽

Axial Thrust ◽

Centrifugal Blood Pump ◽

Flow Passage ◽

Straight Blade ◽

Blood Pumps

Introduction: The miniaturization of blood pumps has become a trend due to the advantage of easier transplantation, especially for pediatric patients. In small-scale pumps, it is much easier and more cost-efficient to manufacture the impeller with straight blades compared to spiral-profile blades. Methods: Straight-blade impeller designs with different blade angles, blade numbers, and impeller flow passage positions are evaluated using the computational fluid dynamics method. Blade angles (θ = 0°, 20°, 30°, and 40°), blade numbers ( N = 5, 6, 7, and 8), and three positions of impeller flow passage (referred to as top, middle, and bottom) are selected as the studied parametric values. Results: The numerical results reveal that with increasing blade angle, the pressure head and the hydraulic efficiency increase, and the average scalar shear stress and the normalized index of hemolysis decrease. The minimum radial force and axial thrust are obtained when θ equals 20°. In addition, the minimum average scalar shear stress and normalized index of hemolysis values are obtained when N = 6, and the maximum values are obtained when N = 5. Regarding the impeller flow passage position, the axial thrust and the stagnation area forming in the impeller eye are reduced as the flow passage height declines. Conclusion: The consideration of a blade angle can greatly improve the performance of blood pumps, although the influence of the blade number is not very easily determined. The bottom position of the impeller flow passage is the best design.

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In vitro hemocompatibility investigation for the development of low-flow centrifugal blood pumps with less platelet clogging

The International Journal of Artificial Organs ◽

10.1177/03913988211052570 ◽

2021 ◽

pp. 039139882110525

Author(s):

Akiko Oota-Ishigaki ◽

Takashi Yamane ◽

Daisuke Sakota ◽

Ryo Kosaka ◽

Osamu Maruyama ◽

...

Keyword(s):

Platelet Aggregation ◽

Low Flow ◽

Blood Pump ◽

Centrifugal Pumps ◽

Aggregation Index ◽

Centrifugal Blood Pump ◽

Pump Design ◽

Blood Pumps ◽

Adhesion Rate

Low-flow blood pumps rated under 1 L/min are emerging for new medical applications, such as hemofiltration in acute use. In those pumps, platelet adhesion and aggregation have to be carefully considered because of clogging risk in the filter part. To find an acceptable hemocompatibility that can be applied to low-flow centrifugal blood pump design, the platelet aggregation index, clogging on a micromesh filter, and the hemolysis index were investigated using a low-flow blood pump designed for hemofiltration use. We conducted circulation testing in vitro using fresh porcine blood and two centrifugal pumps with different impeller inlet shapes. The Negative Log Platelet Aggregation Threshold Index (NL-PATI), which reflects the ability of residual platelets to aggregate, and flow rate were measured during reflux for 60 min, and the Normalized Index of Hemolysis (NIH (g/20 min)) was calculated. In addition, blood cell clogging after reflux was observed on the micromesh filter by SEM, and the adhesion rate was calculated. Our results showed that the platelet clogging on the micromesh filter occurred when the average NL-PATI was greater than 0.28 and the average NIH (g/20 min) was greater than 0.01. In contrast, platelet clogging on the micromesh was suppressed when NL-PATI was less than 0.17 and the NIH (g/20 min) was less than 0.003. These values might be used as acceptable hemocompatibility of low-flow centrifugal blood pumps with suppressed platelet clogging for hemofiltration pumps.

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Geometric Optimization of an Extracorporeal Centrifugal Blood Pump with an Unshrouded Impeller Concerning Both Hydraulic Performance and Shear Stress

Processes ◽

10.3390/pr9071211 ◽

2021 ◽

Vol 9 (7) ◽

pp. 1211

Author(s):

Bo Huang ◽

Miao Guo ◽

Bin Lu ◽

Qingyu Wu ◽

Zhigang Zuo ◽

...

Keyword(s):

Shear Stress ◽

Vascular Diseases ◽

Geometric Optimization ◽

Blood Pump ◽

Original Design ◽

Centrifugal Blood Pump ◽

Low Degree ◽

Blood Pumps ◽

Optimized Model ◽

Computation Load

Centrifugal blood pumps have provided a powerful artificial support system for patients with vascular diseases. In the design process, geometrical optimization is usually needed to acquire a more biocompatible model for clinical uses. In the current paper, we propose a method for multi-objective optimization concerning both the hydraulic and the hemolytic performances of the pump based on the near-orthogonal array in which the traditional hemolysis index (HI) is replaced with the maximum scalar shear stress criteria to reduce the computation load. The method is demonstrated with the optimization of an extracorporeal centrifugal blood pump with an unshrouded impeller. CFD studies on the original and nine modified pump models are carried out. The calculated hydraulic performances of the optimized model are also compared against the experiments for validation of the numeric method, with an error of 3.6% at the original design point. The resulting blood pump with low maximum scalar shear stress (132.2 Pa) shows a low degree of calculated HI (1.69 × 10−3).

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A Compact Centrifugal Blood Pump for Extracorporeal Circulation: Design and Performance

Journal of Biomechanical Engineering ◽

10.1115/1.3138680 ◽

1987 ◽

Vol 109 (3) ◽

pp. 272-278 ◽

Cited By ~ 9

Author(s):

Shinobu Tanaka ◽

Shuzo Yamamoto ◽

Ken-ichi Yamakoshi ◽

Akira Kamiya

Keyword(s):

Thrombus Formation ◽

Animal Experiments ◽

Left Ventricular ◽

Blood Pump ◽

Assisted Circulation ◽

In Vitro Tests ◽

Outer Diameter ◽

Centrifugal Blood Pump ◽

And Performance

A new compact centrifugal blood pump driven by a miniature DC servomotor has been designed for use for short-term extra corporeal and cardiac-assisted circulation. The impeller of the pump was connected directly to the motor by using a simple-gear coupling. The shaft for the impeller was sealed from blood by both a V-ring and a seal bearing. Either pulsatile or nonpusatile flow was produced by controlling the current supply to the motor. The pump characteristics and the degree of hemolysis were evaluated with regard to the configuration of the impeller with a 38-mm outer diameter in vitro tests; the impeller having the blade angles at the inlet of 20 deg and at the outlet of 50 deg was the most appropriate as a blood pump. The performance in an operation, hemolysis and thrombus formation in the pump were assessed by a left ventricular bypass experiment in dogs. It was suggested by this study that this prototype pump appears promising for use not only in animal experiments but also in clinical application.

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PIV Measurements of Flow in a Centrifugal Blood Pump: Steady Flow

Journal of Biomechanical Engineering ◽

10.1115/1.1865189 ◽

2004 ◽

Vol 127 (2) ◽

pp. 244-253 ◽

Cited By ~ 18

Author(s):

Steven W. Day ◽

James C. McDaniel

Keyword(s):

Shear Stress ◽

Artificial Heart ◽

Heart Valves ◽

Blood Pump ◽

Reynolds Stresses ◽

Centrifugal Blood Pump ◽

Flow Rates ◽

Blood Damage ◽

Artificial Heart Valves ◽

Stagnant Flow

Magnetically suspended left ventricular assist devices have only one moving part, the impeller. The impeller has absolutely no contact with any of the fixed parts, thus greatly reducing the regions of stagnant or high shear stress that surround a mechanical or fluid bearing. Measurements of the mean flow patterns as well as viscous and turbulent (Reynolds) stresses were made in a shaft-driven prototype of a magnetically suspended centrifugal blood pump at several constant flow rates (3–9L∕min) using particle image velocimetry (PIV). The chosen range of flow rates is representative of the range over which the pump may operate while implanted. Measurements on a three-dimensional measurement grid within several regions of the pump, including the inlet, blade passage, exit volute, and diffuser are reported. The measurements are used to identify regions of potential blood damage due to high shear stress and∕or stagnation of the blood, both of which have been associated with blood damage within artificial heart valves and diaphragm-type pumps. Levels of turbulence intensity and Reynolds stresses that are comparable to those in artificial heart valves are reported. At the design flow rate (6L∕min), the flow is generally well behaved (no recirculation or stagnant flow) and stress levels are below levels that would be expected to contribute to hemolysis or thrombosis. The flow at both high (9L∕min) and low (3L∕min) flow rates introduces anomalies into the flow, such as recirculation, stagnation, and high stress regions. Levels of viscous and Reynolds shear stresses everywhere within the pump are below reported threshold values for damage to red cells over the entire range of flow rates investigated; however, at both high and low flow rate conditions, the flow field may promote activation of the clotting cascade due to regions of elevated shear stress adjacent to separated or stagnant flow.

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The Sealless and Bearingless Rotor Blood Pump System: Adaptation to the Circulatory System and In Vitro Advantages in Efficiency, Flow Characteristics, and Boundary Conditions of Thermal Heat Up

Assisted Circulation 3 ◽

10.1007/978-3-642-74404-4_18 ◽

1989 ◽

pp. 215-224 ◽

Cited By ~ 3

Author(s):

G. Bramm ◽

D. B. Olsen

Keyword(s):

Boundary Conditions ◽

Circulatory System ◽

Flow Characteristics ◽

Blood Pump ◽

Pump System ◽

System Adaptation

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In vitro evaluation of multi‐objective physiological control of the centrifugal blood pump

Artificial Organs ◽

10.1111/aor.13639 ◽

2020 ◽

Vol 44 (8) ◽

pp. 785-796 ◽

Cited By ~ 2

Author(s):

Tarcisio Leao ◽

Bruno Utiyama ◽

Jeison Fonseca ◽

Eduardo Bock ◽

Aron Andrade

Keyword(s):

Blood Pump ◽

Physiological Control ◽

Centrifugal Blood Pump ◽

In Vitro Evaluation ◽

Multi Objective

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STRUCTURAL DESIGN AND NUMERICAL SIMULATION OF THE DIFFUSER FOR MAGLEV AXIAL BLOOD PUMP

Journal of Mechanics in Medicine and Biology ◽

10.1142/s0219519414500456 ◽

2014 ◽

Vol 14 (03) ◽

pp. 1450045

Author(s):

HUACHUN WU ◽

GAO GONG ◽

ZHIQIANG WANG ◽

YEFA HU ◽

CHUNSHENG SONG

Keyword(s):

Optimization Design ◽

Design Method ◽

Leading Edge ◽

Pressure Head ◽

Hydraulic Performance ◽

Blood Pump ◽

Blade Angle ◽

Blade Number ◽

Blade Thickness ◽

Blood Pumps

Hydraulic performance is an especially important factor for maglev axial blood pumps that have been used in patients with heart disease. Most maglev axial blood pumps basically consist of a straightener, an impeller and a diffuser. The diffuser plays a key role in the performance of the maglev axial blood pump to provide an adequate pressure head and increase the hydraulic efficiency. Maglev axial blood pumps with various structural diffusers exhibit different hydraulic performance. In this study, computational fluid dynamics (CFD) analysis was performed to quantify hydrodynamic in a maglev axial blood pump with a flow rate of 6 L/min against a pressure head of 100 mmHg to optimize the diffuser structure. First, we design the prototype of diffuser structure based on traditional design method, establish blood flow channel models using commercial software ANSYS FLUENT. Specifically, compare the performance of pump with the diffusers of different parameters, such as the leading edge blade angle, blade-thickness and blade-number. The results show that the diffuser structures with the thickening blade by arc airfoil law, blade-number of 6, leading edge blade angle of 24°, and trailing edge blade angle of 90° exhibited the best hydraulic performance which could be utilized in the optimization design of maglev axial blood pumps.

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