Tesla blood pumps demonstrate a reduced propensity for hemolysis and thrombosis compared with vane blood pumps. Considering the restricted driving force within the secondary flow channel of vane blood pumps, along with the low hydraulic efficiency of conventional Tesla blood pumps and their internal flow characteristics that significantly contribute to hemolysis and thrombosis, this study introduces a set of vanes atop the rotor of the Tesla blood pump. This forms a dual-fluid domain rotor, and an axial dual-outlet volute shell structure is adopted to realize the separation of the fluid domains. Through numerical simulations of the new structure, a comparative analysis was conducted in this study on the internal flow characteristics of double-outlet and single-outlet volute shells, and symmetric and asymmetric cross-sections of the same rotor. The results indicate that the flow field distribution is more uniform under the double-outlet volute shell structure, and overall energy dissipation is decreased. After implementing the double-outlet design, in the asymmetric cross-section, compared with the symmetric cross-section, the fluid velocity gradient and turbulent kinetic energy at the tongue of the septum are reduced, and the fluid velocity gradient at the convergence of the diffuser tube outlets are also decreased. The maximum scalar stress is lower, and the decline in head and efficiency is mitigated. Moreover, compared with the single-outlet volute shell, the hemolysis index in the asymmetric cross-section is reduced. In summary, this paper proposes a novel dual-outlet centrifugal disk blood pumps, which can provide a reference for the structural design and performance optimization of magnetically levitated centrifugal blood pumps.
Heart-Assist Devices ; Humans ; Equipment Design ; Hemolysis ; Computer Simulation

Objective To observe the effect of numerical simulation technique for predicting effect of self-expanding prosthetic valve(SEV)stents for treating type 0 bicuspid aortic valve(BAV)stenosis with different implantation strategies.Methods Based on CT angiography data from a patient with type 0 BAV stenosis and asymmetric calcification,three-dimensional models of aortic root wall,aortic valve calcification,native valve and SEV were reconstructed.ABAQUS/Explicit dynamic analysis module was used to observe the interaction between SEV stents and aortic root including root stress and stent deformation under different implantation strategies(implantation depths of high,medium or low,and implantation centers of central or eccentric position).Results When SEV was implanted centrally at low depth and central position,the Von Mises stress on aortic root wall was the highest,with mean and peak value of 2.28 and 45.30 kPa,respectively.When SEV was implanted at medium depth and central position,the average eccentricity of stent across all planes was the highest(0.254),while when implanted at high depth and eccentric position,the average ellipticity in planes S1-S3 was the minimal(0.124).Conclusion Different SEV implantation strategies resulted in varying interactions between stent and aortic root.Numerical simulation technique could be used to determine the implantation center and depth based on the size and location of type 0 BAV calcification,which was helpful to reducing rupture risk of aortic annulus,increasing durability and improving prognosis of SEV stent.

Objective To investigate the impact of variations in volute cross-sectional area on the flow characteristics and hemolytic performance of centrifugal blood pumps by designing six volute structures.Methods Computational fluid dynamics and the Lagrangian method were used to analyze flow characteristics and predict hemolysis in blood pumps with different volute designs.Results The annular volute pump showed the poorest hydraulic performance,while the hydraulic performance of the S-shaped volute was the best,which was improved by 35.29％compared to that of the annular volute.Some volutes experienced stagnation zones at the helical inlet(0°-90°)and significant backflow at the outlet(270°-360°).The downward concave-shaped volute had the highest hemolysis index(HI),i.e.,9.59×10-4.Meanwhile,the HI of the annular volute was the lowest,which was 71.85％less than the concave-shaped volute.Conclusions Reducing the gradient of the area variation at the helical inlet and outlet can prevent flow stagnation and backflow.A higher HI arises due to the prolonged exposure of red blood cells to high shear stress.This study provides a theoretical basis for designing and optimizing volute structures of centrifugal blood pumps.

Objective To investigate the impact of variations in volute cross-sectional area on the flow characteristics and hemolytic performance of centrifugal blood pumps by designing six volute structures.Methods Computational fluid dynamics and the Lagrangian method were used to analyze flow characteristics and predict hemolysis in blood pumps with different volute designs.Results The annular volute pump showed the poorest hydraulic performance,while the hydraulic performance of the S-shaped volute was the best,which was improved by 35.29％compared to that of the annular volute.Some volutes experienced stagnation zones at the helical inlet(0°-90°)and significant backflow at the outlet(270°-360°).The downward concave-shaped volute had the highest hemolysis index(HI),i.e.,9.59×10-4.Meanwhile,the HI of the annular volute was the lowest,which was 71.85％less than the concave-shaped volute.Conclusions Reducing the gradient of the area variation at the helical inlet and outlet can prevent flow stagnation and backflow.A higher HI arises due to the prolonged exposure of red blood cells to high shear stress.This study provides a theoretical basis for designing and optimizing volute structures of centrifugal blood pumps.

Objective To study the effects of different clearance conditions(equal upper and lower axial clearance,change of upper/lower axial clearance,axial displacement of blades)on efficiency and hemolysis performance of blood pump.Methods The blood pumps under three kinds of clearance conditions were numerically simulated by computational fluid dynamics.Results For efficiency,when the upper and lower axial clearance was equal,the lower axial clearance was unchanged and the upper axial clearance was reduced,the efficiency of blood pump could be improved by 0.85%,1.71%and 2.90%,respectively.While the upper shaft clearance remained unchanged,the lower shaft clearance was decreased by 1.18%.For hemolysis,the increase of the clearance could reduce the hemolysis index(HI)under the first two clearance conditions,while the axial migration of the blade wheel would increase the HI.When the upper axial clearance was unchanged and the lower axial clearance was 0.3 mm,the HI was the largest,which was 8.65×10-4.When the upper and lower axial clearance was 0.7 mm,the HI was the smallest,which was 4.51×10-4.Conclusions Improving blood pump clearance is helpful to optimize the performance of blood pump.This study can provide some references for the design and optimization of interstitial structure of blood pump.

Objective To observe the effect of numerical simulation technique for predicting effect of self-expanding prosthetic valve(SEV)stents for treating type 0 bicuspid aortic valve(BAV)stenosis with different implantation strategies.Methods Based on CT angiography data from a patient with type 0 BAV stenosis and asymmetric calcification,three-dimensional models of aortic root wall,aortic valve calcification,native valve and SEV were reconstructed.ABAQUS/Explicit dynamic analysis module was used to observe the interaction between SEV stents and aortic root including root stress and stent deformation under different implantation strategies(implantation depths of high,medium or low,and implantation centers of central or eccentric position).Results When SEV was implanted centrally at low depth and central position,the Von Mises stress on aortic root wall was the highest,with mean and peak value of 2.28 and 45.30 kPa,respectively.When SEV was implanted at medium depth and central position,the average eccentricity of stent across all planes was the highest(0.254),while when implanted at high depth and eccentric position,the average ellipticity in planes S1-S3 was the minimal(0.124).Conclusion Different SEV implantation strategies resulted in varying interactions between stent and aortic root.Numerical simulation technique could be used to determine the implantation center and depth based on the size and location of type 0 BAV calcification,which was helpful to reducing rupture risk of aortic annulus,increasing durability and improving prognosis of SEV stent.

Objective To study the effects of different clearance conditions(equal upper and lower axial clearance,change of upper/lower axial clearance,axial displacement of blades)on efficiency and hemolysis performance of blood pump.Methods The blood pumps under three kinds of clearance conditions were numerically simulated by computational fluid dynamics.Results For efficiency,when the upper and lower axial clearance was equal,the lower axial clearance was unchanged and the upper axial clearance was reduced,the efficiency of blood pump could be improved by 0.85%,1.71%and 2.90%,respectively.While the upper shaft clearance remained unchanged,the lower shaft clearance was decreased by 1.18%.For hemolysis,the increase of the clearance could reduce the hemolysis index(HI)under the first two clearance conditions,while the axial migration of the blade wheel would increase the HI.When the upper axial clearance was unchanged and the lower axial clearance was 0.3 mm,the HI was the largest,which was 8.65×10-4.When the upper and lower axial clearance was 0.7 mm,the HI was the smallest,which was 4.51×10-4.Conclusions Improving blood pump clearance is helpful to optimize the performance of blood pump.This study can provide some references for the design and optimization of interstitial structure of blood pump.

The impeller, as a key component of artificial heart pumps, experiences high shear stress due to its rapid rotation, which may lead to hemolysis. To enhance the hemolytic performance of artificial heart pumps and identify the optimal combination of blade parameters, an optimization design for existing pump blades is conducted. The number of blades, outlet angle, and blade thickness were selected as design variables, with the maximum shear stress within the pump serving as the optimization objective. A back propagation (BP) neural network prediction model was established using existing simulation data, and a grey wolf optimization algorithm was employed to optimize the blade parameters. The results indicated that the optimized blade parameters consisted of 7 impeller blades, an outlet angle of 25 °, and a blade thickness of 1.2 mm; this configuration achieved a maximum shear stress value of 377 Pa-representing a reduction of 16% compared to the original model. Simulation analysis revealed that in comparison to the original model, regions with high shear stress at locations such as the outer edge, root, and base significantly decreased following optimization efforts, thus leading to marked improvements in hemolytic performance. The coupling algorithm employed in this study has significantly reduced the workload associated with modeling and simulation, while also enhancing the performance of optimization objectives. Compared to traditional optimization algorithms, it demonstrates distinct advantages, thereby providing a novel approach for investigating parameter optimization issues related to centrifugal artificial heart pumps.
Neural Networks, Computer ; Algorithms ; Heart-Assist Devices ; Hemolysis ; Humans ; Equipment Design ; Stress, Mechanical ; Computer Simulation

Objective:To study the clinical characteristics of patients with brucella bloodstream infection in different age groups, and provide a basis for clinicians to take targeted diagnosis and treatment measures. Methods:Demographic data and general condition (age, sex, occupation, location, onset season, source of infection, clinical stage), clinical characteristics (main clinical symptoms and complications), and laboratory test results (routine and pathogenic tests) of adult patients with brucella bloodstream infection admitted to the Affiliated Hospital of Chengde Medical College from January 2015 to January 2020 were collected. According to the age stratification standards recommended by the World Health Organization, the patients were divided into a young group (18 - 44 years old), a middle-aged group (45 - 59 years old), and an elderly group (≥60 years old), and various indicators among different age groups were compared and analyzed. Results:A total of 75 patients were included, including 15 cases (20.00%) in the young group, 37 cases (49.33%) in the middle-aged group, and 23 cases (30.67%) in the elderly group. Among them, 61 cases (81.33%) were males and 14 cases (18.67%) were females, with statistically significant differences in gender ratios among different age groups (χ 2 = 7.28, P = 0.021). The majority of patients were farmers (64 cases, 85.33%), and 92.00% (69/75) of the patients came from rural areas. The main sources of infection were infected cattle and sheep, and contaminated food (39 cases, 52.00%). The main season of onset was spring and summer (45 cases, 60.00%). The clinical staging was mainly in the acute phase (66 cases, 88.00%). In terms of clinical symptoms, the young group of patients had no symptoms of low back pain, while the incidence rates of low back pain in the middle-aged and elderly groups were 35.14% (13/37) and 30.43% (7/23), respectively. There was a statistically significant difference between the three groups (χ 2 = 6.98, P = 0.031). In terms of complications, there were no cases of concurrent spondylitis in the young group of patients. The incidence rates of spondylitis in the middle-aged and elderly groups were 32.43% (12/37) and 34.78% (8/23), respectively. There was a statistically significant difference among the three groups (χ 2 = 6.86, P = 0.032). In terms of routine laboratory examinations, there were statistically significant differences in the proportion of blood lymphocytes and albumin levels among patients of different age groups ( F = 3.41, 3.27, P = 0.038, 0.044). In terms of pathogenic examination, there was a statistically significant difference in the median alarm time for positive blood culture among patients of different age groups ( H = 9.54, P = 0.008), with the middle-aged group having the longest (66.24 h) and the elderly group having the shortest (58.80 h). Conclusions:The clinical characteristics of patients with brucella bloodstream infection vary among different age groups, middle-aged and elderly patients are prone to low back pain symptoms, accompanied by spondylitis. Clinicians should pay attention to the patient's own characteristics and provide targeted diagnosis and treatment.

ObjectiveTo investigate the value of peripheral blood long non-coding RNA-LET (lncRNA-LET) in the diagnosis of chronic hepatitis B (CHB) cirrhosis, and to provide a basis for early clinical diagnosis and treatment of liver cirrhosis. MethodsA total of 175 CHB patients who attended The Affiliated Hospital of Chengde Medical University from March 2017 to May 2019 were enrolled, among whom 52 patients with hepatitis B cirrhosis were enrolled as cirrhosis group and 123 patients without the pathological changes of liver cirrhosis were enrolled as non-cirrhosis group. A total of 40 healthy individuals who underwent physical examination in our hospital during the same period of time were enrolled as normal control group. Liver function parameters and the level of lncRNA-LET in peripheral blood were measured for all subjects. The t-test was used for comparison of continuous data between two groups; an analysis of variance was used for comparison between multiple groups, and the least significant difference t-test was used for further comparison between two groups. The chi-square test was used for comparison of categorical data between groups, and the Kruskal-Wallis H test was used for comparison of ranked data. A Pearson correlation analysis was performed to investigate correlation. The receiver operating characteristic (ROC) curve was used to investigate the value of peripheral blood lncRNA-LET in predicting liver cirrhosis. Results Compared with the normal control group, the cirrhosis group and the non-cirrhosis group had significantly higher serum levels of the liver function parameters total bilirubin (TBil), total bile acid (TBA), albumin (Alb), and alanine aminotransferase (ALT) (all P＜0.05) and a significantly lower serum level of cholinesterase (ChE) (P＜0.05); compared with the non-cirrhosis group, the cirrhosis group had significantly higher serum levels of TBil, TBA, Alb, and ALT (all P＜0.05) and a significantly lower serum level of ChE (P＜0.05). Compared with the normal control group, the cirrhosis group and the non-cirrhosis group had significantly lower relative expression of lncRNA-LET in peripheral blood (P＜0.05), and the cirrhosis group had significantly lower relative expression of lncRNA-LET in peripheral blood than the non-cirrhosis group (P＜0.05). The relative expression of lncRNA-LET decreased significantly with the increase in liver fibrosis stage (P＜0.05). In the patients with CHB, the relative expression of lncRNA-LET in peripheral blood was negatively correlated with liver fibrosis stage, TBil, TBA, Alb, and ALT (r=-0.352,-0.372,-0.364, and -0.410, all P＜0.001) and was positively correlated with ChE (r=0.340, P＜0.001). The ROC curve was used to analyze the value of peripheral blood lncRNA-LET in predicting liver cirrhosis, and the area under the ROC curve was 0934, with an optimal cut-off value of 0.833, a sensitivity of 84.57%, and a specificity of 80.57%. ConclusionThe expression level of lncRNA-LET in peripheral blood decreases with the progression of liver fibrosis and has a good value in the diagnosis of CHB cirrhosis, and therefore, it can be used as a potential biological indicator for the diagnosis of liver cirrhosis.