To visualize and quantify the hemodynamics in the aortic arch in normal individuals, we used velocity distribution, retrograde flow, vortex formation, and mean energy loss (mEL) at different cardiac cycles in our study. We performed Vector flow mapping (VFM) analysis by using echocardiography in 87 healthy volunteers. The results showed that ① in different sections of the aortic arch, a skewed peak flow velocity (Vp) always appeared in the period of rapid ejection but in different distribution. The systolic flow in the entire aortic arch rose rapidly from near-zero at the point of iso-volumetric contraction to the peak velocity at the period of rapid ejection, and then decreased gradually; ② In the period of iso-volumetric relaxation, retrograde flow and vortex were observed in all subjects in the inner wall of the entire aortic arch; and ③ The change rule of mEL in the entire aortic arch was similar to that of flow velocity. VFM can provide insights into the intra-aortic arch flow patterns, and offer essential fundamentals about flow features associated with common aortic diseases.
Objective To investigate and compare the effects of succinylated gelatin injection and saline priming on the first hour blood pressure in critically ill patients receiving continuous renal replacement therapy (CRRT). Methods Inpatients who received continuous venous-venous dialysis filtration therapy in the intensive care unit of West China Hospital of Sichuan University between January and May 2024 were selected. The patients were randomly divided into an experimental group (colloidal solution group) and a control group (crystalloid solution group) in a 1∶1 ratio. The colloidal solution group used succinylated gelatin injection as the priming solution, and used the dual connection method to draw blood to the machine. The patient’s systolic blood pressure, diastolic blood pressure, mean arterial pressure and heart rate at 10 minutes before and 0, 1, 3, 5, 10, 30 and 60 minute after CRRT initiation, the name and dosage of vascular compression drugs pumped intravenously at 0, 30 and 60 minutes, and the liquid inlet and outlet in the first hour were monitored and recorded. The crystalloid solution group used normal saline as the priming solution, and the rest of the methods were the same as those of the colloidal solution group. Two groups of patients were compared for changes in blood pressure and heart rate during the first hour of CRRT, as well as the incidence of hypotension. Results A total of 208 patients were included, with 104 cases in each group. There was no significant difference in baseline data between the two groups (P>0.05). At 3 minutes after CRRT, the systolic blood pressure of the crystalloid solution group was lower than that of the colloidal solution group [(122.56±23.82) vs. (129.43±25.46) mm Hg (1 mm Hg=0.133 kPa); t=−2.005, P=0.046]. There was no statistically significant difference in diastolic blood pressure, mean arterial pressure, or heart rate between the two groups at different time points (P>0.05). The intra group comparison results showed that the systolic blood pressure of the crystalloid solution group decreased compared to before at 1, 3, 5, and 10 minutes after CRRT (P<0.05), while the diastolic blood pressure and mean arterial pressure decreased compared to before at 3, 5, and 10 minutes after the start of CRRT (P<0.05); there was no statistically significant difference in blood pressure of the colloidal solution group among different time points after the start of CRRT (P>0.05). The heart rate of the crystalloid solution group was higher at 10 minutes after the start of CRRT than at 3 minutes after CRRT (P=0.045); 60 minutes after the start of CRRT, the heart rate in the colloidal solution group was lower than that 0 minutes after CRRT (P=0.032); there was no statistically significant difference between the two groups at other time points within each group (P>0.05). On the first hour of CRRT, there was a statistically significant difference in the incidence of hypotension between the two groups [33 cases (31.7%) vs. 18 cases (17.3%); χ2=5.845, P=0.016]. Conclusions The use of colloidal solution pre-flushing is more advantageous to improving the decrease in blood pressure in the first hour of CRRT in severe patients than crystalloid solution group pre-flushing. And it can reduce the incidence of hypotension in the first hour of CRRT in severe patients.
ObjectiveTo investigate the application of computational fluid dynamics (CFD) in hemodynamic evaluation of aortic root reconstruction.MethodsThe clinical data of 1 patient with severe aortic valve stenosis was analyzed. Enhanced CT images were used as the original data, and professional software was used to reconstruct the three-dimensional (3D) model and fluid mechanics simulation of the aorta (including preoperative, postoperative and ideal conditions).ResultsThe 3D reconstruction model could directly present the distribution of valve calcification and the dilatation of the ascending aorta. The remodeled sinotubular junction and sinus structure were observed in the model under postoperative and ideal conditions. The improvement of ascending aorta dilatation was evaluated statistically by the diameter distribution before and after surgery. CFD simulation showed that the area of high flow velocity, pressure intensity and wall shear stress before surgery were consistent with the expansion area of the ascending aorta, and the restricted blood flow acceleration was observed at the angle between the arch and the descending aorta. In the ideal condition, the streamline of blood at the descending aorta was more stable and flat compared with preoperative or postoperative conditions, and there was no obvious abnormal high pressure and high wall shear stress area in the ascending aorta. The cardiopulmonary bypass time was 106 min, of which the aortic cross-clamp time was 60 min. The cardiac echocardiography indicated that the aortic valve worked well, and the peak systolic blood velocity was 1.7 m/s. The length of hospital stay after surgery was 12 d, including 2 d in ICU. The ventilator use time was 11.6 h. The patient did not have any remarkable discomfort during the 1-year follow-up.ConclusionCFD can be used to evaluate anatomic and hemodynamic abnormalities before aortic root reconstruction surgery. Postoperative reconstruction simulation can be performed again to evaluate the surgical effect, and meanwhile, virtual improvement can be tried for the unresolved problems to accumulate diagnosis and treatment experience, so as to provide patients with more accurate and personalized diagnosis and treatment procedure.
Vena cava filter is a filter device designed to prevent pulmonary embolism caused by thrombus detached from lower limbs and pelvis. A new retrievable vena cava filter was designed in this study. To evaluate hemodynamic performance and thrombus capture efficiency after transplanting vena cava filter, numerical simulation of computational fluid dynamics was used to simulate hemodynamics and compare it with the commercialized Denali and Aegisy filters, and in vitro experimental test was performed to compare the thrombus capture effect. In this paper, the two-phase flow model of computational fluid dynamics software was used to analyze the outlet blood flow velocity, inlet-outlet pressure difference, wall shear stress on the wall of the filter, the area ratio of the high and low wall shear stress area and thrombus capture efficiency when the thrombus diameter was 5 mm, 10 mm, 15 mm and thrombus content was 10%, 20%, 30%, respectively. Meanwhile, the thrombus capture effects of the above three filters were also compared and evaluated by in vitro experimental data. The results showed that the Denali filter has minimal interference to blood flow after implantation, but has the worst capture effect on 5 mm small diameter thrombus; the Aegisy filter has the best effect on the trapping of thrombus with different diameters and concentrations, but the low wall shear stress area ratio is the largest; the new filter designed in this study has a good filtering and capture efficiency on small-diameter thrombus, and the area ratio of low wall shear stress which is prone to thrombosis is small. The low wall shear stress area of the Denali and Aegisy filters is relatively large, and the risk of thrombosis is high. Based on the above results, it is expected that the new vena cava filter designed in this paper can provide a reference for the design and clinical selection of new filters.
Hematopoietic stem cells (HSCs) are tissue specific stem cells that replenish all mature blood lineages during the lifetime of an individual. Hematopoietic cell clusters in the aorta of vertebrate embryos play a pivotal role in the formation of the adult blood system. Recently, people have learned a lot about the embryonic HSCs on their development and homing. During their differentiation, HSCs are regulated by the transcription factors, such as Runx1 and Notch signaling pathway, etc. MicroRNAs also regulate the self-renewal and differentiation of hematopoietic stem/progenitor cells on the post-transcriptional levels. Since the onset of circulation, the formation of HSCs and their differentiation into blood cells, especially red blood cells, are regulated by the hemodynamic forces. It would be of great significance if we could treat hematologic diseases with induced HSCs in vitro on the basis of fully understanding of hemotopoietic stem cell development. This review is focused on the advances in the research of HSCs' development and regulation.
Hemodynamics plays a vital role in the development and progression of cardiovascular diseases, and is closely associated with changes in morphology and function. Reliable detection of hemodynamic changes is essential to improve treatment strategies and enhance patient prognosis. The combination of computational fluid dynamics with cardiovascular imaging technology has extended the accessibility of hemodynamics. This review provides a comprehensive summary of recent developments in the application of computational fluid dynamics for cardiovascular hemodynamic assessment and a succinct discussion for potential future development.
Heart failure is one kind of cardiovascular disease with high risk and high incidence. As an effective treatment of heart failure, artificial heart is gradually used in clinical treatment. Blood compatibility is an important parameter or index of artificial heart, and how to evaluate it through hemodynamic design and in vitro hemolysis test is a research hotspot in the industry. This paper first reviews the research progress in hemodynamic optimization and in vitro hemolysis evaluation of artificial heart, and then introduces the research achievements and progress of the team in related fields. The hemodynamic performance of the blood pump optimized in this paper can meet the needs of use. The normalized index of hemolysis obtained by in standard vitro hemolysis test is less than 0.1 g/100 L, which has good hemolysis performance in vitro. The optimization method described in this paper is suitable for most of the development of blood pump and can provide reference for related research work.
Sleep is a complex physiological process of great significance to physical and mental health, and its research scope involves multiple disciplines. At present, the quantitative analysis of sleep mainly relies on the “gold standard” of polysomnography (PSG). However, PSG has great interference to the human body and cannot reflect the hemodynamic status of the brain. Functional near infrared spectroscopy (fNIRS) is used in sleep research, which can not only meet the demand of low interference to human body, but also reflect the hemodynamics of brain. Therefore, this paper has collected and sorted out the related literatures about fNIRS used in sleep research, concluding sleep staging research, clinical sleep monitoring research, fatigue detection research, etc. This paper provides a theoretical reference for scholars who will use fNIRS for fatigue and sleep related research in the future. Moreover, this article concludes the limitation of existing studies and points out the possible development direction of fNIRS for sleep research, in the hope of providing reference for the study of sleep and cerebral hemodynamics.
This paper aims to explore the feasibility of building a finite element model of left atrial diverticulum (LAD) using reverse engineering software based on computed tomography (CT) images. The study was based on a three-dimensional cardiac CT images of a atrial fibrillation patient with LAD. The left atrium and LAD anatomical features were accurately reproduced by using Geomagic Studio 12 and Mimics 15 reverse engineering software. In addition, one left atrial model with LAD and one without LAD were created with ANSYS finite element analysis software, and the validity of the two models were verified. The results show that it is feasible to establish the LAD finite element model based on cardiac three-dimensional CT images using reverse engineering software. The results of this paper will lay a theoretical foundation for further hemodynamic analysis of LAD.
Objective To identify potential hub genes and key pathways in the early period of septic shock via bioinformatics analysis. MethodsThe gene expression profile GSE110487 dataset was downloaded from the Gene Expression Omnibus database. Differentially expressed genes were identified by using DESeq2 package of R project. Then Kyoto Encyclopedia of Genes and Genomes (KEGG) and Gene Ontology (GO) analyses were constructed to investigated pathways and biological processes using clusterProfiler package. Subsequently, protein-protein interaction (PPI) network was mapped using ggnetwork package and the molecular complex detection (MCODE) analysis was implemented to further investigate the interactions of differentially expressed genes using Cytoscape software. Results A total of 468 differentially expressed genes were identified in septic shock patients with different responses who accepted early supportive hemodynamic therapy, including 255 upregulated genes and 213 downregulated genes. The results of GO and the KEGG pathway enrichment analysis indicated that these up-regulated genes were highly associated with the immune-related biological processes, and the down-regulated genes are involved in biological processes related to organonitrogen compound, multicellular organismal process, ion transport. Finally, a total of 23 hub genes were identified based on PPI and the subcluster analysis through MCODE software plugin in Cytoscape, which included 19 upregulated hub genes, such as CD28, CD3D, CD8B, CD8A, CD160, CXCR6, CCR3, CCR8, CCR9, TLR3, EOMES, GZMB, PTGDR2, CXCL8, GZMA, FASLG, GPR18, PRF1, IDO1, and additional 4 downregulated hub genes, such as CNR1, GPER1, TMIGD3, GRM2. KEGG pathway enrichment analysis and GO functional annotation showed that differentially expressed genes were primarily associated with the items related to cytokine-cytokine receptor interaction, natural killer cell mediated cytotoxicity, hematopoietic cell lineage, T cell receptor signaling pathway, phospholipase D signaling pathway, cell adhesion molecules, viral protein interaction with cytokine and cytokine receptor, primary immunodeficiency, graft-versus-host disease, type 1 diabetes mellitus. Conclusions Some lymphocytes such as T cells and natural killer cells, cytokines and chemokines participate in the immune process, which plays an important role in the early treatment of septic shock, and CD160, CNR1, GPER1, and GRM2 may be considered as new biomarkers.