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Introduction
Published in Wilmer W Nichols, Michael F O'Rourke, Elazer R Edelman, Charalambos Vlachopoulos, McDonald's Blood Flow in Arteries, 2022
Pulsatile pressure is recorded routinely in human cardiovascular diagnostic laboratories, operating rooms and critical care units in the present generation, and pulsatile flow patterns are now used invasively and noninvasively for the quantification of cardiac and vascular shunts, of valvular and vascular stenoses, and of systemic and pulmonary hypertension. These techniques have assumed practical importance in routine cardiologic and vascular diagnostic, investigative, monitoring and therapeutic procedures.
Pulse Pressure
Published in Giuseppe Mancia, Guido Grassi, Konstantinos P. Tsioufis, Anna F. Dominiczak, Enrico Agabiti Rosei, Manual of Hypertension of the European Society of Hypertension, 2019
Pierre Boutouyrie, James E. Sharman
‘One obvious characteristic of blood flow in arteries is that it’s pulsatile’. This first sentence of the first edition of Blood Flow in Arteries (1) is emblematic of a current of research which has grown since the 1950s. Blood pressure (BP) is pulsatile, so two ways of expressing this phenomenon are to describe BP either through the extremes, systolic BP (SBP), the maximum of BP observed during systole, and diastolic BP (DBP), the minimum before heart contraction, or through the mean BP (MBP) and the oscillations around the mean BP (pulse pressure, PP) (2). The former view has prevailed since the invention of the cuff and mercury column by Riva-Rocci in 1896 and auscultation by Korotkoff in 1905. Since then, a wealth of evidence has been produced as to the physiology of high BP; BP being a risk factor for cardiovascular, cerebral and kidney events; and treatment of hypertension providing undisputed benefits (3). It has also obscured for half a century the latter, despite the earlier attempts at measuring pulses by Marey and Mahumet in the nineteenth century (4). Indeed, because of the increase in life expectancy, populations are ageing, and blood pressure patterns combine chronic hypertension and ageing (5). A common pattern of BP in populations is increase in SBP together with decrease in DBP, i.e. increased pulse pressure, which cannot be explained through increased peripheral resistance (6). The objective of this chapter is to describe how measurement of PP relates to the pulsatile flow in arteries, the physiology of PP, how it is measured and how it may be considered in the management of patients.
Cardiac surgery
Published in Brian J Pollard, Gareth Kitchen, Handbook of Clinical Anaesthesia, 2017
The use of pulsatile flow is controversial and outcome data on its benefits are lacking. Physiological models would suggest that such flow improves perfusion and oxygen uptake; achieving it requires intermittent roller pump action or external reservoir compression, both of which add complexity to the circuit. It is not commonly used.
Transarterial radioembolization: a systematic review on gaining control over the parameters that influence microsphere distribution
Published in Drug Delivery, 2023
T. J. Snoeijink, T. G. Vlogman, J. Roosen, E. Groot Jebbink, K. Jain, J.F.W. Nijsen
Second, patient specific flow waveforms are often absent due to limited knowledge about the in vivo situation. Only three out of five in vitro studies used pulsatile flow while others assumed a constant inflow. Furthermore, the pulsatile flow waveforms in most studies were based on literature (Basciano et al., 2010) and therefore neglect possible peculiarities in the shape of the waveform for a specific patient. At present it is unclear to what degree such simplifications influence the microsphere distribution. Given the sensitivity of PRMs to local flow features, this is a legitimate concern and crucial information to assess the validity of simulated and experimental results. Therefore, future in vitro and CFD models should investigate the impact of different inlet flow waveforms.
Wall shear stress indicators influence the regular hemodynamic conditions in coronary main arterial diseases: cardiovascular abnormalities
Published in Computer Methods in Biomechanics and Biomedical Engineering, 2023
M. Ferdows, K. E. Hoque, M.Z.I. Bangalee, M. A. Xenos
The numerical study involves the effect of different hemodynamic parameters especially WSS indices in various sizes of stenosis models. The pulsatile flow patterns with incompressible and laminar blood flows have been applied for observing the behavior of the hemodynamic factors in the patient’s models. The hemodynamic conditions inside the coronary model are assumed as a Newtonian fluid. The simulation procedures are conducted by solving the following set of non-linear partial differential equations. The blood flow is considered as an incompressible fluid and can be illustrated by the equations as follows:
Analysis of the time-velocity curve in phase-contrast magnetic resonance imaging: a phantom study
Published in Computer Assisted Surgery, 2019
Jieun Park, Junghun Kim, Yongmin Chang, Sung Won Youn, Hui Joong Lee, Eun-Ju Kang, Ki-Nam Lee, Vojtěch Suchánek, Sinjae Hyun, Jongmin Lee
In conclusion, non-invasive blood flow measurement techniques (PC-MRI and Doppler US) were compared by using the electromagnetic flowmeter as a reference standard. The difference in pulsatile flow characteristics pattern was confirmed. The result of this study was showed the similar trend found in the literature [33,34]. This study has analyzed characteristics of time-velocity curves by measuring the maximum, minimum, and average velocities, the full-width at half-maximum (FWHM) and the ascending gradient (AG). PC-MRI has shown more obtuse pulsation characteristics and Doppler US showed the closest waveforms to the reference patterns. Moreover, we found conversion equations which allow the measured data to be compatible with those of a reference electromagnetic flowmeter. The conversion equations can help that the PC-MRI method can achieve better results.