Nonuniform Circumferential Deformation of the Abdominal Aorta: A Cross-Species Comparison
0
Citation
0
Reference
10
Related Paper
Abstract:
Arterial wall biomechanics are thought to be important in aneurysm development and atherosclerotic plaque localization. Vessel wall dilation occurs because of pulsatile blood flow during the cardiac cycle. Until recently, it was commonly assumed that this dilation occurred concentrically about the center of the lumen. However, dynamic MR, CT, and ultrasound imaging techniques have now shown that aortic wall motion undergoes unequal circumferential deformation during the cardiac cycle. This phenomenon has been observed in both humans and pigs [1, 2]. The purpose of our study was to determine whether variations in circumferential aortic wall dilation persist across mammalian species.Keywords:
Cardiac cycle
Pulsatile flow
Dilation (metric space)
Lumen (anatomy)
Abdominal aorta
Biomechanics
Arterial wall
In this study, a patient-specific carotid artery model was analyzed with an open source program foam-extend. The research includes the effect of arterial wall deformation by fluid-structure analysis. Pulsatile velocity cycle is trained for 144 patients with different hemodynamic parameters, by machine learning algorithm using blood flow velocity measured from 337 points of the carotid artery. Data used for training is obtained from an open source in the literature. Here, the machine learning algorithm was created by the help of an open source code Phyton. Then, using trained values of machine learning, and the known systole and diastole blood pressures for a specific chosen patient, the patient-specific pulsatile velocity cycle was estimated. The estimated pulsatile velocity cycle was then fitted to Fourier series. This pulsatile velocity cycle is used as the input boundary condition for the model analyzed in foam-extend. The outlet boundary condition, pulsatile pressure cycle is found by 4-Element Windkessel algorithm. Wall shear stresses and time averaged wall shear stresses were obtained for both the rigid and fluid structure interaction models, and variation of displacement throughout the pulsatile cycle was found for the FSI model. Wall shear stresses, velocity, and displacements were obtained high at peak systole, consistent with pulsatile cycles. Like the wall shear stresses, the time averaged wall shear stresses for the FSI model were also found lower than the rigid model. The wall shear stresses showed an increase towards the exit of internal and external carotid artery.
Pulsatile flow
Cardiac cycle
Systole
Cite
Citations (1)
The in vitro effects of pulsatile and non-pulsatile blood pumps on human red blood cells were investigated. Group I (Sarns, Inc., non-pulsatile pump) showed significantly less hemolysis (p < 0.05) than Group II (Cobe-Stockert, non-pulsatile roller pump). Group III (Sarns, pulsatile roller pump) and Group IV (Stockert, pulsatile roller pump showed significantly less hemolysis (p < 0.05). Both Sams and Stockert non-pulsatile roller pumps showed significantly (p < .05) less hemolysis at three and four hours of circulation than the Sarns and Stockert pulsatile pumps.
Pulsatile flow
Peristaltic pump
Cite
Citations (1)
Pulsatile flow
Cite
Citations (97)
Aims: With increased use of ventricular assist devices (VADs), non-pulsatile systems have attained more interest for long-term use. We present the results of mechanical circulatory support (MCS) with pulsatile and non-pulsatile LVADs employed in patients for over 1 year.
Pulsatile flow
Cite
Citations (0)
Pulsatile flow
Cite
Citations (0)
Pulsatile flow
Cardiac cycle
Systole
Beat (acoustics)
Cite
Citations (19)
Pulsatile flow
Artificial heart
Flow Control
Cite
Citations (0)
There has been renewed interest in the study of pulsatile blood flow. The ever increasing use of extracorporeal circulation adds clinical significance to these studies. Moreover an understanding of the factors involved in pulsatile blood flow is important in the design of an artificial heart and in cardiac augmentation systems. The effectiveness and efficiency of such a device may be dependent upon factors related to pulsatile flow. Previous studies from our laboratory and by others have indicated that pulsatile flow is associated with decreased systemic and pulmonary vascular resistance as compared with non-pulsatile flow(1, 2). In order to study further the hemodynamic effects of pulsatile and non-pulsatile blood flow, a new compact pulsatile pump has been devised. It is the purpose of this report to describe it, discuss its advantages over pre-existing models, and mention its experimental use.
Pulsatile flow
Cite
Citations (6)
Pulsatile flow
Cite
Citations (1)
Abstract Signal strength in time‐of‐flight magnetic resonance (MR) anglograpny of pulsatile flow is modulated by the time‐varying intraluminal magnetization strength. The specific appearance of MR angiographlc images therefore depends on the relationship of different phase‐encoding steps to the pulsatile flow waveform. Cardiac‐phase gating can be applied with phase‐encoding reordering to acquire different regions of k‐space during the desired phases of the cardiac cycle. The authors have developed a simulation program for evaluating the merits of different encoding strategies for pulsatile flow. The model was validated with phantom studies. High signal intensity relative to that in conventional MR anglographic studies can be attained with strategies that impose relatively small penalties in total acquisition time.
Pulsatile flow
Cardiac cycle
SIGNAL (programming language)
Flip angle
Cite
Citations (18)