Hemodynamic Analysis Research Articles

Hemodynamic Analysis and Diagnosis Based on Multi-Deep Learning Models

This study employs nine distinct deep learning models to categorize 12,444 blood cell images and automatically extract from them relevant information with an accuracy that is beyond that achievable with traditional techniques. The work is intended to improve current methods for the assessment of human health through measurement of the distribution of four types of blood cells, namely, eosinophils, neutrophils, monocytes, and lymphocytes, known for their relationship with human body damage, inflammatory regions, and organ illnesses, in particular, and with the health of the immune system and other hazards, such as cardiovascular disease or infections, more in general. The results of the experiments show that the deep learning models can automatically extract features from the blood cell images and properly classify them with an accuracy of 98%, 97%, and 89%, respectively, with regard to the training, verification, and testing of the corresponding datasets.

Combined use of magnetic microbeads for endothelial cell isolation and enhanced cell engraftment in myocardial repair.

Background: The regenerative potential of the heart after injury is limited. Therefore, cell replacement strategies have been developed. However, the engraftment of transplanted cells in the myocardium is very inefficient. In addition, the use of heterogeneous cell populations precludes the reproducibility of the outcome. Methods: To address both issues, in this proof of principle study, we applied magnetic microbeads for combined isolation of eGFP+ embryonic cardiac endothelial cells (CECs) by antigen-specific magnet-associated cell sorting (MACS) and improved engraftment of these cells in myocardial infarction by magnetic fields. Results: MACS provided CECs of high purity decorated with magnetic microbeads. In vitro experiments revealed that the angiogenic potential of microbead-labeled CECs was preserved and the magnetic moment of the cells was strong enough for site-specific positioning by a magnetic field. After myocardial infarction in mice, intramyocardial CEC injection in the presence of a magnet resulted in a strong improvement of cell engraftment and eGFP+ vascular network formation in the hearts. Hemodynamic and morphometric analysis demonstrated augmented heart function and reduced infarct size only when a magnetic field was applied. Conclusion: Thus, the combined use of magnetic microbeads for cell isolation and enhanced cell engraftment in the presence of a magnetic field is a powerful approach to improve cell transplantation strategies in the heart.

Influence of different outflow boundary conditions on hemodynamic analysis of cerebral aneurysm

Influence of different outflow boundary conditions on hemodynamic analysis of cerebral aneurysm

Hemodynamic analysis of carotid endarterectomy

Atherosclerotic stenosis of the carotid artery may lead to cerebral infarction, stroke, and other serious consequences, and it is usually treated clinically with carotid endarterectomy. By comparing the pre- and postoperative flow fields, it can be shown that the operation improves hemodynamic parameters, such as the velocity, wall shear stress, and wall pressure of the local flow field of the carotid artery. However, previous studies have rarely considered the difference between postoperative and healthy carotid flow fields, and thus, the cause of any postoperative restenosis may remain hidden. Therefore, this study constructed preoperative, postoperative, and (hypothetically) healthy carotid artery models based on the real vascular structure data of a patient and applied numerical simulations verified by physical models to compare hemodynamic parameters, such as flow rate, flow state, and wall shear. The results showed that after the operation, the maximum carotid blood flow velocity decreased from 2.8 to 1.02 m/s, the maximum wall shear stress decreased from 190 to ∼75 Pa, the wall pressure of the carotid inlet recovered from 3000 to 400 Pa, and the vortex in the distal internal carotid artery disappeared. In addition, this study also found a vortex and the low-level wall shear stress of approximately 5 Pa remained in the carotid bifurcation after the operation, which also lacked spiral flow, unlike the healthy model. Therefore, due to the morphological differences between the postoperative and healthy carotid artery, adverse hemodynamic factors and a potential risk of postoperative restenosis will remain after the procedure.

Retracted: Hemodynamic Analysis of Pipeline Embolization Device Stent for Treatment of Giant Intracranial Aneurysm under Unsupervised Learning Algorithm.

[This retracts the article DOI: 10.1155/2022/8509195.].

Predicting the Risk of Type B Aortic Dissection Using Hemodynamic Parameters in Aortic Arches: A Comparative Study between Healthy and Repaired Aortas

Background and objectiveThe development of acute aortic dissection (AD) remains unpredictable due to the intricate nature of the AD mechanism and the varied patient-specific aortic anatomy. The aim of this study was to simulate the hemodynamic parameters in the aortas before the onset of TBAD with healthy controls. MethodsThis study numerically assessed the effectiveness of hemodynamic indicators in predicting the risk of type B AD (TBAD) by investigating the differences in hemodynamic parameters between healthy and repaired aortas (aortas before TBAD development). Four wall shear stress (WSS)-based indicators and three helicity-based indicators were adopted and analyzed. ResultsThe results showed that more pathological anatomical feathers can be observed in the repaired aortas. For WSS-based indicators, only averaged cross flow index (CFI) and oscillatory shear index OSI (CFI, 1.03 ± 0.07 vs. 0.83 ± 0.10 and OSI, 0.12 ± 0.03 vs. 0.04 ± 0.02) (all p<0.001) were significantly higher in the repaired aortas than those in the healthy aortas. On the other hand, average helicity in the repaired aortas also showed a significant difference compared with that in healthy aortas (h1, 3.88 ± 5.55 vs. -8.03 ± 14.16) (p<0.05). Furthermore, the skewed helical structure and flow disturbance was found in the repaired aortas. Conclusion1) There are marked differences in pathological anatomical features, such as aortic dilation, elongation and tortuosity between the healthy aortas and repaired aortas, and the corresponding hemodynamic indicators also have also been significantly changed. 2) Compared with anatomical characteristics, hemodynamic indicators may be more accurate for predicting the risk and location of TBAD, such as the OSI and CFI index were significantly enhanced in the region where the entry tears have occurred. 3) In clinical practice, anatomical features remain important factors for assessing the risk for development of TBAD; however, hemodynamic analyses with quantitative data and more visualizing characteristics have showed promising potential in this aspect.

Optical transparency and label-free vessel imaging of zebrafish larvae in shortwave infrared range as a tool for prolonged studying of cardiovascular system development

Optical techniques are utilized for the non-invasive analysis of the zebrafish cardiovascular system at early developmental stages. Being based mainly on conventional optical microscopy components and image sensors, the wavelength range of the collected and analyzed light is not out of the scope of 400–900 nm. In this paper, we compared the non-invasive optical approaches utilizing visible and near infrared range (VISNIR) 400–1000 and the shortwave infrared range (SWIR) 900–1700 nm. The transmittance spectra of zebrafish tissues were measured in these wavelength ranges, then vessel maps, heart rates, and blood flow velocities were calculated from data in VISNIR and SWIR. An increased pigment pattern transparency was registered in SWIR, while the heart and vessel detection quality in this range is not inferior to VISNIR. Obtained results indicate an increased efficiency of SWIR imaging for monitoring heart function and hemodynamic analysis of zebrafish embryos and larvae and suggest a prolonged registration period in this range compared to other optical techniques that are limited by pigment pattern development.

Hemodynamic Analysis Shows High Wall Shear Stress Is Associated with Intraoperatively Observed Thin Wall Regions of Intracranial Aneurysms.

Studying the relationship between hemodynamics and local intracranial aneurysm (IA) pathobiology can help us understand the natural history of IA. We characterized the relationship between the IA wall appearance, using intraoperative imaging, and the hemodynamics from CFD simulations. Three-dimensional geometries of 15 IAs were constructed and used for CFD. Two-dimensional intraoperative images were subjected to wall classification using a machine learning approach, after which the wall type was mapped onto the 3D surface. IA wall regions included thick (white), normal (purple-crimson), and thin/translucent (red) regions. IA-wide and local statistical analyses were performed to assess the relationship between hemodynamics and wall type. Thin regions of the IA sac had significantly higher WSS, Normalized WSS, WSS Divergence and Transverse WSS, compared to both normal and thick regions. Thicker regions tended to co-locate with significantly higher RRT than thin regions. These trends were observed on a local scale as well. Regression analysis showed a significant positive correlation between WSS and thin regions and a significant negative correlation between WSSD and thick regions. Hemodynamic simulation results were associated with the intraoperatively observed IA wall type. We consistently found that elevated WSS and WSSNorm were associated with thin regions of the IA wall rather than thick and normal regions.

Morphometric and Hemodynamic Analysis of the Compressed Iliac Vein

Purpose: To investigate the relationship between the morphological structure and hemodynamic properties of the compressed iliac vein and explore the reason for the formation of thrombosis in the compressed iliac vein. Materials and Methods: A total of 11 patients with iliac vein compression syndrome (IVCS) were included in this study, and their iliac veins were reconstructed in 3 dimensions (3D). The morphological structures of the iliac veins (confluence angle, degree of stenosis) were analyzed based on the 3D model. Variations in the hemodynamic properties of the iliac vein were investigated at 4 typical moments in one cardiac cycle, and the relationship between the different morphological configurations and the pressure difference was investigated. Results: In the region of the compressed iliac vein, the blood flow velocity is accelerated and the pressure changes abruptly accompanied by the increase in pressure difference. Higher time averaged wall shear stress (TAWSS) and lower relative residence time (RRT) appeared in stenosis regions of compressed iliac vein, while TAWSS was low and RRT was large near the stenosis position. There was a strong positive correlation between the degree of stenosis and the pressure difference (r=0.894), and a positive correlation between the confluence angle of the iliac vein and the pressure difference (r=0.638). Conclusion: The morphological structure of the compressed iliac vein has an obvious influence on the hemodynamic surroundings; the pressure difference becomes larger when the degree of stenosis and the confluence angle increase. The iliac vein luminal areas with low TAWSS and high RRT near the compressed location can impede blood flow and lead to accumulation of blood components, which may increase the risk of thrombosis formation and should be fully considered in the treatment of IVCS.

Increased biventricular hemodynamic forces in precapillary pulmonary hypertension

Precapillary pulmonary hypertension (PHprecap) is a condition with elevated pulmonary vascular pressure and resistance. Patients have a poor prognosis and understanding the underlying pathophysiological mechanisms is crucial to guide and improve treatment. Ventricular hemodynamic forces (HDF) are a potential early marker of cardiac dysfunction, which may improve evaluation of treatment effect. Therefore, we aimed to investigate if HDF differ in patients with PHprecap compared to healthy controls. Patients with PHprecap (n = 20) and age- and sex-matched healthy controls (n = 12) underwent cardiac magnetic resonance imaging including 4D flow. Biventricular HDF were computed in three spatial directions throughout the cardiac cycle using the Navier–Stokes equations. Biventricular HDF (N) indexed to stroke volume (l) were larger in patients than controls in all three directions. Data is presented as median N/l for patients vs controls. In the RV, systolic HDF diaphragm-outflow tract were 2.1 vs 1.4 (p = 0.003), and septum-free wall 0.64 vs 0.42 (p = 0.007). Diastolic RV HDF apex-base were 1.4 vs 0.87 (p < 0.0001), diaphragm-outflow tract 0.80 vs 0.47 (p = 0.005), and septum-free wall 0.60 vs 0.38 (p = 0.003). In the LV, systolic HDF apex-base were 2.1 vs 1.5 (p = 0.005), and lateral wall-septum 1.5 vs 1.2 (p = 0.02). Diastolic LV HDF apex-base were 1.6 vs 1.2 (p = 0.008), and inferior-anterior 0.46 vs 0.24 (p = 0.02). Hemodynamic force analysis conveys information of pathological cardiac pumping mechanisms complementary to more established volumetric and functional parameters in precapillary pulmonary hypertension. The right ventricle compensates for the increased afterload in part by augmenting transverse forces, and left ventricular hemodynamic abnormalities are mainly a result of underfilling rather than intrinsic ventricular dysfunction.

Hemodynamic Analysis of the Geometric Features of Side Holes Based on GDK Catheter.

Hemodialysis is an important means to maintain life in patients with end-stage renal disease (ESRD). Approximately 76.8% of patients who begin hemodialysis do so through catheters, which play vital roles in the delivery of hemodialysis to patients. During the past decade, the materials, structures, and surface-coating technologies of catheters have constantly been evolving to ameliorate catheter-related problems, such as recirculation, thrombosis, catheter-related infections, and malfunction. In this study, based on the commercial GDK catheter, six catheter models (GDK, GDK1, GDK2, GDK3, GDK4, and GDK5) with different lumen diameters and different geometric features of side holes were established, and computational flow dynamics (CFD) were used to measure flow rate, shear stress, residence time (RT), and platelet lysis index (PLI). These six catheters were then printed with polycarbonate PC using 3D printing technology to verify recirculation rates. The results indicated that: (1) the catheter with a 5.5 mm outer diameter had the smallest average shear stress in the arterial lumen and the smallest proportion of areas with shear stress &gt; 10 pa. With increasing catheter diameter, the shear stress in the tip volume became lower, the average RT increased, and the PLI decreased due to larger changes in shear stress; (2) the catheters with oval-shaped side holes had smaller shear stress levels than those with circular-shaped holes, indicating that the oval design was more effective; (3) the catheter with parallel dual side holes had uniformly distributed flow around side holes and exhibited lower recirculation rates in both forward and reverse connections, while linear multi-side holes had higher shear stress levels due to the large differences in flow around side holes. The selection of the material and the optimization of the side holes of catheters have significant impacts on hemodynamic performances and reduce the probability of thrombosis, thus improving the efficiency of dialysis. This study would provide some guidance for optimizing catheter structures and help toward the commercialization of more efficient HD catheters.

Abstract 14064: Utility of Tricuspid Annular Plane Systolic Excursion Normalized by Right Ventricular Size in Pulmonary Hypertension to Predict Exercise Capacity, Pulmonary Compliance, and Clinical Outcomes

1. Introduction: While tricuspid annular plane systolic excursion (TAPSE) captures the predominant longitudinal motion of right ventricle (RV), it may not accurately predict ventricular function as the RV dilates. Hence, normalizing TAPSE to ventricular area (in systole: TAPSE/RV-area-S, and diastole: TAPSE/RV-area-D) may lead to improved assessment of right heart function. In this study, we aim to determine the utility of RV size-indexed-TAPSE metrics in predicting exercise capacity and clinical outcomes. 2. Methods: We perform a retrospective analysis of 71 consecutive subjects undergoing invasive exercise hemodynamics with cardiopulmonary exercise test for evaluation of dyspnea. Patients were classified into four groups: pulmonary arterial hypertension, isolated post-capillary, combined pre-/post-capillary PH, and control (no PH) based on hemodynamic analysis. Transthoracic echocardiogram data included: TAPSE (mm), TAPSE-index-D (RV end-diastole area in cm), and TAPSE-index-S (RV end-systole area in cm). Subjects were followed for 12 months after hemodynamic study for adverse events (death, heart failure hospitalization). 3. Results: On ROC analysis of indexed-TAPSE to predict pulmonary compliance (&gt;3.0 ml/mmHg), we identified optimal cutoff of 1.1 for TAPSE-index-D (AUC=0.792, p&lt;0.001), 1.5 for TAPSE-index-S (AUC=0.827, p&lt;0.001), and 17 mm for TAPSE (AUC=0.672, p=0.005). Similar results were obtained for predicting %predicted VO 2 max (&gt;50%). We dichotomized indexed-TAPSE based on ROC analysis. As shown in the Figure, compared to the current recommended TAPSE cut-off of 17 mm, RV size-indexed TAPSE metrics were both superior in predicting adverse outcome (p&lt;0.01). 4. Discussion/Conclusion: Normalizing TAPSE to RV size can capture longitudinal and radial motion of the RV as the ventricle dilates and have better ability to predict clinical outcomes (death and HF hospitalization).

Abstract 10214: Invasive versus Echocardiographic Hemodynamics in the First Genetically Modified Porcine to Human Xenotransplant

Introduction: Our medical center performed the first genetically modified cardiac xenotransplant in human and performed longitudinal invasive and noninvasive hemodynamic measurements throughout the recipient’s hospitalization. We hypothesized that echocardiographic derived hemodynamic assessments would correlate with invasive measurements within the cardiac xenotransplant. Methods: Transthoracic echocardiography (TTE) and right heart catheterizations were performed in the cardiac xenotransplant. Retrospective analysis of TTE and invasive hemodynamics were analyzed to assess correlation between various parameters. The following invasive hemodynamics were measured or calculated: right atrial pressure (RAP), pulmonary artery systolic and diastolic pressures (PASP, PADP), pulmonary vascular resistance (PVR), pulmonary artery pulsatility index (PAPi), cardiac output (CO), cardiac index (CI), right ventricular stroke work index (RVSWI) and cardiac power output (CPO). TTE measurements and calculations included: RAP based on inferior vena cava size and collapsibility, PASP calculated via tricuspid regurgitation velocity (TRV), PADP based on end diastolic pressure gradient, right ventricular outflow time-velocity integral (TVI RVOT), PVR (TRV/TVI RVOT x 10 +0.16) PAPi, CO (using left ventricular outflow tract (LVOT) velocity-time integral and LVOT area), CI (from TTE-derived CO), CPO and RVCPI {4x(TRV) 2 } x TAPSE as a surrogate of RVSWI. Results: Pearson correlation for RVSWI and RVCPI using invasive measurements obtained at the time of TTE was -0.095 and at time of mixed venous blood gas (mVBG) was 0.963. Mean absolute difference in time between mVBG and TTE was 4h 59 min. Pearson correlation for catheter-based continuous CO (CCO) monitoring with TTE was 0.965. Conclusions: In a retrospective analysis of porcine cardiac xenotransplant function, there was a strong correlation between directly measured hemodynamics with TTE, particularly when mVBG was obtained.

Abstract 10753: Phosphodiesterase Type 5 Inhibition and C-c Chemokine Receptor-2 Disruption Synergistically Protect Against Pulmonary Arterial Hypertension in Monocrotaline-Treated Rats: Potential Synergism of Anti-inflammatory Agents and Pulmonary Vasodilator Therapy

BACKGROUND: Whether conventional pulmonary vasodilator therapy and anti-inflammatory agents synergistically protect against pulmonary arterial hypertension (PAH) is unknown. Hypothesis: We tested the hypothesis that a phosphodiesterase type 5 (PDE5) inhibitor and disruption of C-C chemokine receptor (CCR)-2, a receptor for MCP-1, synergistically protect against PAH in monocrotaline (MCT)-treated rats. Methods: Study1:Seven-week-old male Ccr2 (-/-) rats, generated by using the CRISPAR/ Cas9 genome editing technology, or wild-type littermates, treated with MCT (60mg/kg) or vehicle, were subjected to hemodynamic, morphometric and immunohistochemical analyses and mRNA and protein expression studies on day21 (n=40, 4 groups). Study 2: Tadarafil (10mg/kg/d), a PDE5 inhibitor, or vehicle was administered in Ccr2 (-/-) or wild-type MCT rats on days 21-42 (n=71, 4 groups) for evaluating survival and were evaluated hemodynamically on day28. Results: Study1: MCT treatment increased right ventricular systolic pressure (RVSP), an index of right ventricular hypertrophy (Fulton index), indices of pulmonary vascular diseases (%medial wall thickness, %muscularization) and the number of perivascular CD68-positive macrophages in WT rats, all of which were decreased by Ccr2 (-/-) (p&lt;.05). Similarly, an increase in mRNA expression of inflammatory cytokines (IL6 ,TNFa, MCP1, IL1b, TGFb) and a decrease in BMPR2 pathways (BMPR2, pSmad1/5/9 and ID1) as well as an increase in endothelial apoptosis (% cleaved Caspase 3 positive CD31 cells) and a decrease in NO pathways (eNOS and phospho-eNOS/eNOS) in lungs in wild-type MCT rats were reversed by Ccr2 (-/-) on day21 (p&lt;.05) with comparable PDE5 expression. Study2: Tadarafil administration or CCR2(-/-)(p=.03 and p=.02) alone improved the survival in wild type MCT rats. A double intervention synergistically improved the survival in separately treated groups (p=.02 vs CCR2(-/-), p=.04 vs Tadarafil) in MCT rats. Tadarafil treatment on days21-28 decreased RVSP and Fulton index in CCR2(-/-) MCT rats (p&lt;.05). Conclusions PDE5 inhibition and CCR-2 disruption synergistically protect against PAH in MCT-treated rats, suggesting an adjunctive role of a CCR2 inhibitor on top of administering a PDE5 inhibitor for PAH.

Hemodynamic simulation of aneurysmal aorta using a parallel algorithm and a flow-rate based resistance splitting method

Hemodynamic analysis of the aortic aneurysm can provide clinically useful information for the treatment and management of the disease. However, it is still a big challenge to accurately resolve the flow field within a clinically acceptable computing time. In this work, we adopt a two-level domain decomposition-based preconditioned parallel nonlinear solver to solve the unsteady Navier–Stokes equations with three-element Windkessel outlet boundary conditions, where model parameters are estimated by a novel method based on the blood flow rate ratio obtained from the ultrasound. The simulated results are verified by using clinically measured data. Several numerical experiments are performed to show the robustness of the proposed algorithm against different parameters. The proposed algorithm scales up to 2400 processor cores with 50% parallel efficiency and greatly reduces the computing time of the full-size aortic blood flow simulation.

Design and Haemodynamic Analysis of a Novel Anchoring System for Central Venous Pressure Measurement.

In recent years, treatment of heart failure patients has proved to benefit from implantation of pressure sensors in the pulmonary artery (PA). While longitudinal measurement of PA pressure profoundly improves a clinician's ability to manage HF, the full potential of central venous pressure as a clinical tool has yet to be unlocked. Central venous pressure serves as a surrogate for the right atrial pressure, and thus could potentially predict a wider range of heart failure conditions. However, it is unclear if current sensor anchoring methods, designed for the PA, are suitable to hold pressure sensors safely in the inferior vena cava. The purpose of this study was to design an anchoring system for accurate apposition in inferior vena cava and evaluate whether it is a potential site for central venous pressure measurement. A location inferior to the renal veins was selected as an optimal site based on a CT scan analysis. Three anchor designs, a 10-strut anchor, and 5-struts with and without loops, were tested on a custom-made silicone bench model of Vena Cava targeting the infra-renal vena cava. The model was connected to a pulsatile pump system and a heated water bath that constituted an in-vitro simulation unit. Delivery of the inferior vena cava implant was accomplished using a preloaded introducer and a dilator as a push rod to deploy the device at the target area. The anchors were subjected to manual compression tests to evaluate their stability against dislodgement. Computational Fluid Dynamics (CFD) analysis was completed to characterize blood flow in the anchor's environment using pressure-based transient solver. Any potential recirculation zones or disturbances in the blood flow caused by the struts were identified. We demonstrated successful anchorage and deployment of the 10-strut anchor in the Vena Cava bench model. The 10-strut anchor remained stable during several compression attempts as compared with the other two 5-strut anchor designs. The 10-strut design provided the maximum number of contact points with the vessel in a circular layout and was less susceptible to movement or dislodgement during compression tests. Furthermore, the CFD simulation provided haemodynamic analysis of the optimum 10-strut anchor design. This study successfully demonstrated the design and deployment of an inferior vena cava anchoring system in a bench test model. The 10-strut anchor is an optimal design as compared with the two other 5-strut designs; however, substantial in-vivo experiments are required to validate the safety and accuracy of such implants. The CFD simulation enabled better understanding of the haemodynamic parameters and any disturbances in the blood flow due to the presence of the anchor. The ability to place a sensor technology in the vena cava could provide a simple and minimally invasive approach for heart failure patients.

Influence of severe neck angulation on hemodynamic and clinical outcomes following endovascular aneurysm repair: a hemodynamic analysis and a retrospective cohort study.

For patients with severe neck angulation (SNA), hemodynamic and clinical outcomes following endovascular aneurysm repair (EVAR) are still unclear. This study aimed to explore the influence of SNA on hemodynamic and clinical outcomes following EVAR. This study included a hemodynamic analysis and a retrospective cohort study from West China Hospital of Sichuan University between January 2011 and December 2020. The Cox regression model, inverse probability of treatment weighting (IPTW) analysis, sensitivity analysis, and subgroup analysis were applied. Primary outcome was type IA endoleak (T1AEL). In this hemodynamic analysis, nine non-severe neck angulation (nSNA) and 16 SNA idealized models were constructed. We found a significant difference in drag force between SNA and nSNA models (7.016 ± 2.579 N vs. 4.283 ± 1.460 N, P = 0.008), and proximal neck angles were significantly associated with the magnitude of drag force (F = 0.082 × α-0.006 × β + 2.818, α: 95% confidence interval [CI] 0.070-0.094; P = 0.001; β: 95% CI -0.019 to 0.007; P = 0.319). In our cohort study, 514 nSNA patients (71.5 ± 8.5 years; 459 males) and 208 SNA patients (72.5 ± 7.8 years; 135 males) were included, with a median follow-up duration of 34 months (16-63 months). All baseline characteristics were well balanced after IPTW matching. We found that SNA was associated with a significant risk of adverse limb event (hazard ratio [HR] 2.18, 95% CI 1.09-3.12), yet was not associated with T1AEL, overall survival, or reintervention. In patients without proximal or distal additional procedures (DAP), subgroup analyses suggested a significant risk of T1AEL (Proximal: HR 5.25, 95% CI 1.51-18.23; Distal: HR 5.07, 95% CI 1.60-16.07) and adverse limb event (Proximal: HR 2.27, 95% CI 1.01-5.07; Distal: HR 2.91, 95% CI 1.30-6.54) in SNA patients. However, no noticeable difference was observed in patients with proximal or DAP. SNA has a critical influence on hemodynamic and clinical outcomes following EVAR. Appropriate additional procedures may be of great benefit to SNA patients.

Risk factors for the rupture of mirror middle cerebral artery aneurysm using computer-assisted semiautomated measurement and hemodynamic analysis

ObjectivesTo identify the morphologic and hemodynamic risk factor of mirror middle cerebral artery (MCA) aneurysms. MethodsWe conducted a retrospective analysis of 40 paired mirror MCA aneurysms. Aneurysms were divided into ruptured and unruptured groups. Seventeen morphological and nine hemodynamic parameters were measured using computer-assisted semiautomated measurement (CASAM) and computer flow dynamic (CFD) simulation. We performed a paired t-test (for normally distributed data) or a paired Wilcoxon rank-sum (for non-normally distributed data) to analyze all parameters between the groups. Multivariate conditional logistic regression analysis identified independent risk factors. The receiver operating characteristic curve was analyzed to acquire the area under the curve (AUC) and the cutoff values of the independent risk factors. ResultsThere were significant differences in morphological and hemodynamic parameters between the ruptured and unruptured mirror aneurysms. The multivariate logistic analysis showed that the greater size (odds ratio [OR] = 9.807, p = 0.003), smaller neck diameter (OR = 0.285, p = 0.018) and maximum oscillatory shear index (OSI) (OR = 0.000001, p = 0.046) were independently correlated with aneurysm rupture. AUCs for size, N. and maximum OSI were 0.794, 0.695, and 0.701, respectively. The cutoff values of the size, neck diameter, and maximum OSI were 6.30, 5.07, and 0.356437, respectively. ConclusionsMorphology and hemodynamics can help predict aneurysm rupture risks. The more significant size, smaller neck diameter and maximum OSI were independent risk factors for the rupture of MCA aneurysms. The variables could aid practical risk evaluation.

Hemodynamic analysis of a curved artery based on microcirculation boundary.

Microcirculation plays a key role in regulating blood flow but is not considered in previous research of hemodynamics. A curved artery model is established to study its hemodynamic characteristics based on microcirculation boundary. The hemodynamic model of a curved artery is constructed and simulated by computational fluid dynamics. The curved artery model is simulated by fluid-structure interaction. At the same time, a porous medium is used to simulate microcirculation as the outlet boundary. The distribution characteristics of the blood flow velocity, the pressure and the wall shear stress in different sections at different time of the cardiac cycle are obtained. The results show that the velocities in curved arteries decrease and the pressures gradually increase. The blood flow velocity waveform and value are affected and they are sensitive to the microcirculation boundary. However, the pressure value is only affected by the microcirculation function. This work is useful for researchers to deeply understand the hemodynamic characteristics of curved arteries. There is important clinical significance to analyze the pathogenesis of cardiovascular disease considering microcirculation function and its coupling effect.

Flow patterns in the venous sinus of pulsatile tinnitus patients with transverse sinus stenosis and underlying vortical flow as a causative factor

BackgroundTransverse sinus stenosis (TSS) is commonly found in Pulsatile Tinnitus (PT) patients. Vortex flow is prominent in venous sinus with stenosis, and so it is important to determine the distribution and strength of the vortical flow to understand its influence on the occurrence of PT. MethodsIn this study, by using computational fluid dynamics for hemodynamic analysis in patient-specific geometries based on Magnetic Resonance Imaging (MRI), we have investigated the blood flow within the venous sinus of 16 subjects with PT. We have employed both laminar and turbulent flow models for simulations, to obtain (i) streamlines of velocity distribution in the venous sinus, and (ii) pressure distributions of flow patterns in the venous sinus. Then, hemodynamic analysis in the venous sinus recirculation zone was carried out, to determine the flow patterns at the junction of transverse sinuses and sigmoid sinuses. Finally, we have proposed a new model for turbulence evaluation based on the regression analysis of anatomic and hemodynamics parameters. ResultsCorrelation analysis between the anatomical parameters and the hemodynamic parameters has shown that stenosis at the transverse sinus was the main factor in the local hemodynamics variation in the venous sinus of patients; in this context, it is shown that vorticity can be used as a prime indicator of the severity of the stenosis function. Our results have shown a significant correlation between the vorticity and the stenotic maximum velocity (SMV) (r = 0.282, p = 0.004). Then, a parameterized prediction model is proposed to determine the vorticity in terms of flow and anatomic variables, termed as the turbulence eddy prediction model (TEP model). Our result have shown that the TEP model is sensitive to the dominant flow distribution, with a high correlation to the flow-based vorticity (r = 0.809, p = 0.009). ConclusionsThe quantification of the vorticity (as both vorticity and MVV) in the downstream of TSS could be a marker for indication of turbulent energy at the transverse-sigmoid sinus, which could potentially serve as a hemodynamic marker for the functional assessment of the PT-related TSS.