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.
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.
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.
Objective To investigate the clinical efficacy of mitral valve repair technique in the treatment of rheumatic mitral valve lesions. Methods The clinical data of patients diagnosed with rheumatic mitral valve lesions and undergoing mitral valve repair under extracorporeal circulation in our department from 2021 to 2022 were retrospectively analyzed. Results A total of 100 patients were collected, including 78 females and 22 males with an average age of 52 years. There were no secondary open heart or death in the whole group. Extracorporeal circulation time was 136.3±33.1 min, aortic cross-clamping time was 107.6±27.5 min, ventilator use time was 12.9±5.9 h, ICU stay was 2.6±1.4 d, and vasoactive medication use was 823.4±584.4 mg. Before and after the surgery, there were statistical differences in the left ventricular end diastolic diameter, left atrial end systolic diameter, effective mitral valve orifice area, shortening rate of left ventricular short axis, mitral E-peak blood flow velocity, mean mitral transvalvular pressure difference, mitral pressure half-time, and cardiac function graded by New York Heart Association (P＜0.05). While there was no statistical difference in left ventricular ejection fraction or left ventricular end-diastolic volume (P>0.05). Conclusion Overall repair of rheumatic mitral valve lesions can significantly improve the cardiac function and hemodynamics of the patients, and is a good choice for patients with rheumatic mitral valve lesions.
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.
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 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.
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.
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 study analyzed the inherent relation between arterial blood mass flow and muscle atrophy of residual limb to provide some necessary information and theoretical support for the clinical rehabilitation of lower limb amputees. Three-dimensional arterial model reconstruction was performed on both intact side and residual limb of a unilateral transfemoral amputee who is the subject. Then hemodynamic calculation was carried out to comparatively analyze the mass flow state at each arterial outlet of both lower extremities. The muscle atrophy ratio of residual limb was calculated by measuring the cross-sectional area of bilateral muscles. Based on the blood supply relationship, the correlation between arterial blood flow reduction ratio and muscle atrophy ratio was discussed. The results showed that the mass flow of superficial femoral arteries and lateral circumflex femoral arteries severely reduced. Meanwhile rectus femoris, vastus lateralis and vastus medialis which were fed by these arteries showed great atrophy too. On the contrary, the mass flow of deep femoral arteries and medial femoral circumflex arteries slightly reduced. Meanwhile gracilis, adductor longus, long head of biceps which were fed by these arteries showed mild atrophy too. These results indicated that there might be a positive and promotion correlation between the muscle atrophy ratio and the blood mass flow reduction ratio of residual limb during rehabilitation.