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.
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 investigate the correlation of intracranial arachnoid cyst (IAC) with epilepsy and the possible mechanism of seizure induced by IAC. Methods Patients with IAC, who were treated in West China Hospital of Sichuan University between January 2009 and January 2019, were included and divided into IAC with epilepsy group and IAC without epilepsy group according to whether they were diagnosed with epilepsy. We collected the IAC location information of all subjects after the establishment of a three-dimensional spatial coordinate system of MRI images. Computational fluid dynamics technology was used to establish a blood vessel model in cyst area and perform hemodynamic analysis basing on contrast-enhanced CT images. Results A total of 72 patients were enrolled, including 24 in the IAC with epilepsy group and 48 in the IAC without epilepsy group. There was no significant difference between the two groups in terms of sex, age, IAC location, the volumes or the maximum diameters of IAC (P>0.05). Consecutive areas formed by the seven high-risk areas found in the IAC with epilepsy group were located in the temporal area. The seven high-risk areas were simultaneous IAC location in 5 patients in the IAC with epilepsy group and in 1 patient in the IAC without epilepsy group, and the difference was statistically significant (χ2=5.114, P=0.024). Comparison of the hemodynamic parameters between the two types of vascular models revealed similar pressure changes and blood pressure parameters, with lower blood flow and higher mean vascular wall shear stress in the IAC with epilepsy group. Conclusions IAC may cause epilepsy by increasing adjacent blood vessel stenosis and blood vessel wall shear stress through cyst space-occupying effect. The most common location of IAC with epilepsy is the temporal area. The occupying effect of IAC should be considered in the location of epileptogenic foci before surgery for IAC patients with epilepsy.
The development and progression of atherosclerosis and thrombosis are closely related to changes of hemodynamics parameters. Ultrasonic pulse wave Doppler technique is normally used for noninvasively blood flow imaging. However, this technique only provides one-dimensional velocity and depends on the angle between the ultrasound beam and the local velocity vector. In this study, ultrasonic particle image velocimetry method was used to assess whole field hemodynamic changes in normal blood vessels. By using the polynomial fitting method, we investigated the velocity gradient and assessed the shear in different blood flow velocity of 10 healthy rats. It was found that using four polynomial fitting could result in optimal measurement results. The results obtained by ultrasonic particle image velocimetry accorded with the results obtained using Doppler technique. The statistical average of cyclical vessel wall shear stress was positively related to the locational mean velocity. It is proven that ultrasonic particle image velocimetry method could be used to assess directly the real-time whole field hemodynamic changes in blood vessels and was non-invasively, and should be a good prosperous technique for monitoring complex blood flow in stenotic arteries.
Objective To explore the effects of intravenous treprostinil in different doses on the hemodynamics and postoperative outcomes after high-risk total cavo-pulmonary connection (TCPC). MethodsFrom 2018 to 2021, among 189 patients who underwent TCPC in the Department of Pediatric Cardiac Surgery of Fuwai Hospital, 26 high-risk patients who received the intravenous treprostinil therapy were retrospectively analyzed. There were 12 males and 14 females, with an age of 4 (3, 6) years and a weight of 17.6±6.2 kg. The patients were divided into two groups: a high-dose group [15 patients, maintaining dose>10 ng/(kg·min)] and a low-dose group [11 patients, maintaining dose≤10 ng/(kg·min)]. The hemodynamics before treprostinil using and during the first 24 hours after reaching the maintaining dose of treprostinil, and postoperative outcomes of the two groups were investigated. ResultsThe incidence of heterotaxia was higher in the high-dose group (66.7% vs. 18.2%, P=0.021). During the observation period, the mean pulmonary artery pressure decreased from 11.9±3.6 mm Hg to 11.0±3.3 mm Hg in the low-dose group (P=0.013), and from 12.9±4.7 mm Hg to 10.2±3.4 mm Hg in the high-dose group (P=0.001). The decreasing effect in the high-dose group was better than that in the low-dose group (P=0.010). There was no statistical difference in the postoperative outcomes between the two groups (P>0.05). In terms of side effects, patients needed temporarily increased dosage of vasoactive drugs to maintain stable blood pressure during 6-12 h after treprostinil therapy in the high-dose group. ConclusionIn patients after high-risk TCPC, intravenous high-dose treprostinil has a better therapeutic effect on reducing pulmonary artery pressure. However, it should be noted that increased dosage of vasoactive agents may be required to maintain blood pressure stability in patients with high-dose treprostinil.
Quantitative measurement of strain distribution of arterial vessel walls due to pulsatile blood flow within the vascular lumen is valuable for evaluating the elasticity of arterial wall and predicting the evolution of plaques. The present paper shows that the three-dimensional (3D) strain distribution are estimated through uni-directional coupling for 3D vessel and blood models reconstructed from intravascular ultrasound (IVUS) images with the computational fluid dynamics (CFD) numerical simulation technique. The morphology of vessel wall and plaques as well as strain distribution can be visually displayed with pseudo-color coding.
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.
Computational fluid dynamics was used to investigate the effect of the pathogenesis of membranous obstruction of inferior vena cava of Budd-Chiari syndrome with various angles between right hepatic vein and inferior vena cava. Mimics software was used to reconstruct the models from magnetic resonance imaging (MRI) angiograms of inferior vena cava, right hepatic vein, middle hepatic vein and left hepatic vein, and 3DMAX was used to construct the models of 30°, 60°, 90° and 120° angles between right hepatic vein and inferior vena cava, which was based on the reconstructed models.The model was conducted with clinical parameters in terms of wall shear stress distribution, static pressure distribution and blood velocity. The results demonstrated that the differences between wall shear stress and static pressure had statistical significance with various angles between right hepatic vein and inferior vena cava by SPSS. The pathogenesis of membranous obstruction of inferior vena cava had a correlation with the angles between right hepatic vein and inferior vena cava.
Ankle pump exercise (APE) is one of the basic measures to prevent the formation of deep vein thrombosis, which has been widely recognized for its advantages of simplicity, safety, and ease of perform. However, there is still controversy regarding the frequency, duration, angle, position, and adjunctive exercise of APE. This article will review the hemodynamic and hemorheological effects of APE for the prevention of DVT, the current status of clinical application, and new advances in adjunctive APE, in order to provide methods and guidance for clinical staff.