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 study the hemodynamic characteristics of concealed perforator flap in mini-pigs by ultrasonic Doppler technique. Methods Seven 7-month-old mini-pigs, weighing 20-25 kg, were included in the study. The saphenous artery perforator flap (group A, n=4), saphenous artery concealed perforator flap (group B, n=5), and saphenous artery concealed perforator flap combined with sarcolemma (group C, n=5) models were established randomly on both hind limbs of pigs. The pigs and flap survival conditions were observed after operation. The percentage of flap survival area was calculated by Photoshop CS5 software at 5 days after operation. Ultrasonic Doppler technique was performed on the flaps before operation and at immediate, 3 days, and 5 days after operation to record the hemodynamic changes of the flaps. The hemodynamic indicators of saphenous artery (inner diameter, peak systoli velocity, resistance index, and blood flow) and saphenous vein (inner diameter, maximum velocity, and blood flow) were recorded. Results At 1 day after operation, 1 pig died of infection, and the rest survived until the experiment was completed. Finally, the 3 flaps of group A, 4 of group B, and 5 of group C were included in the study. The flaps of the 3 groups all showed swelling after operation, which was most significant at 3 days. At 3 days after operation, the flaps in group B showed partial bruising and necrosis. At 5 days after operation, the flaps in groups A and C were basically alive, and the necrosis area of flap in group B increased further. The percentage of flap survival area in groups A, B, and C were 99.7%±0.5%, 74.8%±26.4%, and 100%, respectively. The percentage of flap was significantly lower in group B than in groups A and C (P<0.05). There was no significant difference between groups A and C (P>0.05). There were significant differences in the hemodynamic indicators of saphenous artery and vein between different time points in 3 groups (P<0.05). There was no significant difference in each indicator between groups at each time point (P>0.05). Conclusion Both the saphenous artery concealed perforator flap and the flap combined with sarcolemma have stable blood flow, but the survival area of the latter was better than the former.
[Abstract]The number of lung transplantation is gradually increasing worldwide, which brings new challenges to the multi-disciplinary team of lung transplantation. The prognosis of lung transplant recipients is seriously affected by the pathophysiological state of specific lung diseases and perioperative risk factors. It is of great significance for these patients to optimize perioperative management according to these factors. Recently, several expert consensus have been published regarding anesthesia management of lung transplantation. Based on the current evidence and clinical practice of West China Hospital, this review summarizes the key points of anesthesia management for lung transplant recipients to guide anesthesiologists' clinical practice.
As an important means of treating heart failure (HF), cardiac assist device has been widely used in clinic. This paper reviews the application status, existing problems and future development trend of cardiac assist devices, including the classification of cardiac assist devices, representative research achievements and indications of the assist devices. It also summarizes the biomechanical indexes of the heart and the new approaches and methods for treating heart failure, as well as the hemodynamic studies of cardiac assist devices in recent years. The research findings provide references for further optimization of cardiac assist device structure and clinical application of the device.
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.
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.
Objective To evaluate the early clinical outcomes of the Renatus? balloon-expandable valve in the treatment of severe aortic stenosis. MethodsFrom November 2021 to April 2022, a total of 38 patients who received Renatus? balloon-expandable valve for severe aortic stenosis in Guangdong Provincial People's Hospital were included. There were 22 males and 16 females, with an average age of 73.7±5.3 years. Mean aortic gradient and peak aortic jet velocity at baseline, post-procedure, and follow-up were compared. Clinical outcomes including all-cause mortality, perivalvular leakage, serious adverse cardiovascular events and the occurrence of permanent pacemaker implantation were assessed. ResultsAll patients completed the procedure successfully without conversion to thoracotomy or perioperative death. The post-implant mean aortic pressure gradient was decreased from 41.5 (27.8, 58.8) mm Hg to 6.0 (3.0, 8.0) mm Hg, and the peak aortic jet velocity was also decreased from 4.1±0.9 m/s to 1.7±0.4 m/s (P<0.001). Pacemakers were required in 2 (5.3%) patients. The median follow-up time was 27.5 (23.0, 87.5) d, with a follow-up rate of 100.0%. The mean aortic gradient was 8.0 (7.0, 10.8) mm Hg and peak aortic jet velocity was 2.0±0.3 m/s, showing significant improvement compared with those in the preoperative period (P<0.001). No severe aortic regurgitation or paravalvular leak was observed. There was no serious cardiovascular adverse event or reoperative event during the study period. ConclusionTranscatheter aortic valve replacement with the domestic Renatus? balloon-expandable valve system is a safe and effective procedure for selected patients with severe aortic stenosis who are at high risk or not candidates for surgical aortic valve replacement.
Objective To explore the hemodynamic assessment after radical surgery in children with tetralogy of Fallot (TOF) by both echocardiography and Mostcare monitor. Methods Clinical data of 63 children with TOF who underwent radical surgery in our hospital from February 2016 to June 2018 were retrospectively analyzed, including 34 males and 29 females, aged 6-24 (9.82±5.77) months. There were 19 patients undergoing transannular patch reconstruction of the right ventricular outflow tract (a transannular patch group) while 44 patients retained the pulmonary valve annulus (a non-transannular patch group) . The echocardiography and Mostcare monitor parameters were recorded and brain natriuretic peptide was tested at the time points of 0, 8, 12, 24 and 48 hours after operation (T 0, T 1, T 2, T 4) to analyze their correlations and the change trend at different time points after radical surgery. Results The left ventricular ejection fraction at T 1 (43.49%±3.82%) was lower than that at T 0 (48.29%±4.55%), T 2 (45.83%±3.69%), T 3 (53.76%±4.43%) and T 4 (60.54%±3.23%, P<0.05). The cardiac index at T 1 (1.85±0.35 L·min?1·m?2) was lower than that at T 0 (2.11±0.38 L·min?1·m?2), T 2 (2.07±0.36 L·min?1·m?2), T 3 (2.42±0.37 L·min?1·m?2) and T 4 (2.82±0.42 L·min?1·m?2, P<0.05). The cardiac circulation efficiency at T1 (0.19±0.05) was lower than that at T 0 (0.22±0.06), T 2 (0.22±0.05), T 3 (0.28±0.06) and T 4 (0.34±0.06, P<0.05). The right ventricular two-chambers view fraction area change at T 1 (23.17%±3.11%) was lower than that at T 0 (25.81%±3.74%), T 2 (25.38%±3.43%), T 3 (30.60%±4.50%) and T 4 (36.94%±5.85%, P<0.05). The pulse pressure variability was the highest at T 0 (18.76%±3.58%), followed by T 1 (14.81%±3.32%), T 2 (12.44%±2.94%), T 3 (10.39%±2.96%) and T 4 (9.18%±1.92%, P<0.05). The blood brain natriuretic peptide was higher at T 1 (846.67±362.95 pg/ml) than that at T 0 (42.60±18.06 pg/ml), T 2 (730.95±351.09 pg/ml), T 3 (510.98±290.39 pg/ml) and T 4 (364.41±243.56 pg/ml, P<0.05). There was no significant difference in left ventricular ejection fraction, cardiac circulation efficiency and heart index between the two groups (P>0.05). The right ventricular two-chambers view fraction area change of the transannular patch group was significantly lower than that of the non-transannular patch group at each time point (P<0.05). The blood brain natriuretic peptide and pulse pressure variability of the transannular patch group were significantly higher than those of the non-transannular patch group (P<0.05). Left ventricular ejection fraction was positively correlated with cardiac index (r=0.637, P=0.001) and cardiac circulation efficiency (r=0.462, P=0.001) while was significantly negatively correlated with blood brain natriuretic peptide (r=–0.419, P=0.001). Conclusion Both methods can accurately reflect the state of cardiac function. Mostcare monitor has a good consistency with echocardiography. Using transannular patch to recontribute right ventricular outflow tract in operation has more influence on right ventricular systolic function. The Mostcare monitor can guide the hemodynamic management after surgery in real time, continuously and accurately.
This paper aims to analyze the impact of splenic vein thrombosis (SVT) on the hemodynamic parameters in hepatic portal vein system. Based on computed tomography (CT) images of a patient with portal hypertension and commercial software MIMICS, the patient's portal venous system model was reconstructed. Color Doppler ultrasound method was used to measure the blood flow velocity in portal vein system and then the blood flow velocities were used as the inlet boundary conditions of simulation. By using the computational fluid dynamics (CFD) method, we simulated the changes of hemodynamic parameters in portal venous system with and without splenic vein thrombosis and analyzed the influence of physiological processes. The simulation results reproduced the blood flow process in portal venous system and the results showed that the splenic vein thrombosis caused serious impacts on hemodynamics. When blood flowed through the thrombosis, blood pressure reduced, flow velocity and wall shear stress increased. Flow resistance increased, blood flow velocity slowed down, the pressure gradient and wall shear stress distribution were more uniform in portal vein. The blood supply to liver decreased. Splenic vein thrombosis led to the possibility of forming new thrombosis in portal vein and surroundings.
Surgical intervention for chronic thoracoabdominal aortic dissecting aneurysms (cTAADA) is regarded as one of the most challenging procedures in the field of vascular surgery. For nearly six decades, open repair predominantly utilizing prosthetic grafts has been the treatment of choice for cTAADA. With advances in minimally invasive endovascular technologies, two novel surgical approaches have emerged: total endovascular stent-graft repair and hybrid procedures combining retrograde debranching of visceral arteries with endovascular stent-graft repair (abbreviated as hybrid procedure). Although total endovascular stent-graft repair offers reduced trauma and quicker recovery, limitations persist in clinical application due to hostile anatomical requirements of the aorta, high costs, and the lack of universally available stent-graft products. Hybrid repair, integrating the minimally invasive ethos of endovascular repair with visceral artery debranching techniques, has increasingly become a significant surgical modality for managing thoracoabdominal aneurysms, especially in cases unsuitable for open surgery or total endovascular treatment due to anatomical constraints such as aortic tortuosity or narrow true lumens in dissections. Recent enhancements in hybrid surgical approaches include ongoing optimization of visceral artery reconstruction strategies based on hemodynamic analyses, and exploration of the comparative benefits of staged versus concurrent surgical interventions.
