scholarly journals An Ascending Aortic Haemodynamic Comparison Between Normotensive and Hypertensive Subjects

2018 ◽  
Vol 2 (1) ◽  
pp. 16
Author(s):  
Vijay Kumar Narayana ◽  
Rajeev Sharma ◽  
Niranjan Murthy
Keyword(s):  
Blood Pressure ◽  
Blood Flow ◽  
Ejection Fraction ◽  
Pressure Gradient ◽  
Aortic Blood Flow ◽  
Ejection Time ◽  
Acceleration Time ◽  
Aortic Blood ◽  
Ascending Aortic Diameter ◽  
Deceleration Time

<p><strong>Background:</strong> Systemic hypertension, a common disorder with potentially serious complications, exerts ill effects through structural and functional modifications of arterial wall. Haemodynamics play an important role in the development of atherosclerosis. Local hemodynamic temporal pressure and wall shear stress are important for understanding the mechanisms leading to various complications in cardiovascular function.</p><p><strong>Objectives:</strong> Since we could not find such a study in literature involving Indian population, this prompted us to investigate and establish the relationship between the blood pressure and the ascending aortic pulse wave parameters in normal individuals and compare the same with hypertensives.</p><p><strong>Material and Methods:</strong> A case control study was done in a tertiary care hospital involving 25 hypertensive parents and further compared with 25 normotensive subjects of same age group acting as control. The GE ̶ P 100 Doppler echocardiography machine was used to study acceleration time, deceleration time, ejection time, ejection fraction, peak flow velocity and pressure gradient in hypertensives and compared the same with age matched normotensive. Also ascending aortic diameter was mapped at the annulus.</p><p><strong>Results:</strong> The results of our study confirmed our assumption that in hypertensive the ascending aortic haemodynamic parameters are abnormal and both systolic and diastolic blood pressure does exert a statistically significant influence on the Doppler parameters of ascending aorta. The acceleration time, deceleration time, pressure gradient and ejection time showed statistically significant increase in hypertensives when compared to normotensive. At the same time the ejection fraction and the ascending aortic diameter showed a statistically significant decrease than normotensive.</p><p><strong>Conclusion:</strong> We would conclude to say that the Doppler parameters of ascending aortic blood flow are abnormal in hypertensives. This altered haemodynamics may lead to further ill effects by way of altered peripheral haemodynamics. This Doppler evaluation of ascending aortic blood flow can be developed as a clinical tool for evaluating hypertensives and assessing the benefit of treatment of hypertension.</p>

scholarly journals Estimation of changes in instantaneous aortic blood flow by the analysis of arterial blood pressure

2012 ◽  
Vol 112 (11) ◽  
pp. 1832-1838 ◽  
Author(s):  
Tatsuya Arai ◽  
Kichang Lee ◽  
Robert P. Marini ◽  
Richard J. Cohen
Keyword(s):  
Blood Pressure ◽  
Blood Flow ◽  
Cardiac Output ◽  
Stroke Volume ◽  
Arterial Blood Pressure ◽  
Aortic Blood Flow ◽  
Windkessel Model ◽  
Arx Model ◽  
Arterial Blood ◽  
Aortic Blood

The purpose of this study was to introduce and validate a new algorithm to estimate instantaneous aortic blood flow (ABF) by mathematical analysis of arterial blood pressure (ABP) waveforms. The algorithm is based on an autoregressive with exogenous input (ARX) model. We applied this algorithm to diastolic ABP waveforms to estimate the autoregressive model coefficients by requiring the estimated diastolic flow to be zero. The algorithm incorporating the coefficients was then applied to the entire ABP signal to estimate ABF. The algorithm was applied to six Yorkshire swine data sets over a wide range of physiological conditions for validation. Quantitative measures of waveform shape (standard deviation, skewness, and kurtosis), as well as stroke volume and cardiac output from the estimated ABF, were computed. Values of these measures were compared with those obtained from ABF waveforms recorded using a Transonic aortic flow probe placed around the aortic root. The estimation errors were compared with those obtained using a windkessel model. The ARX model algorithm achieved significantly lower errors in the waveform measures, stroke volume, and cardiac output than those obtained using the windkessel model ( P < 0.05).

Failure of acute saralasin to reverse chronic hypertension in fetal lambs

1991 ◽  
Vol 260 (4) ◽  
pp. R811-R816
Author(s):  
D. F. Anderson ◽  
N. D. Binder
Keyword(s):  
Blood Pressure ◽  
Blood Flow ◽  
Arterial Blood Pressure ◽  
Upper Body ◽  
Chronic Hypertension ◽  
Aortic Blood Flow ◽  
Flow Reduction ◽  
Arterial Blood ◽  
Aortic Blood ◽  
Blood Flow Reduction

Upper body arterial hypertension developed in 12 fetal lambs after chronic suprarenal aortic blood flow reduction. Sixty minutes after blood flow reduction, intravenous saralasin infusion was able to reduce upper body mean arterial blood pressure to control levels. Although saralasin infusion was able to decrease upper body arterial blood pressure after 1 day of hypertension, it was not able to return blood pressure to control levels. Three or more days later, saralasin was unable to cause a significant reduction in upper body arterial blood pressure. We conclude that, although the renin-angiotensin system has a role in maintaining the elevated blood pressure after greater than or equal to 1 day of suprarenal aortic blood flow reduction, some other mechanism also participates. We have ruled out a role for changing blood volume, and our results suggest that an elevation of plasma catecholamines is not responsible. Some other pathway for fluid regulation available to the fetus may be responsible.

scholarly journals Vasorelaxant and Hypotensive Effects of Jaboticaba Fruit (Myrciaria cauliflora) Extract in Rats

2015 ◽  
Vol 2015 ◽  
pp. 1-8 ◽  
Author(s):  
Daniela Medeiros Lobo de Andrade ◽  
Carolina de Fátima Reis ◽  
Patrícia Ferreira da Silva Castro ◽  
Leonardo Luiz Borges ◽  
Nathalia Oda Amaral ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Blood Flow ◽  
Femoral Vein ◽  
Soluble Guanylyl Cyclase ◽  
Aortic Blood Flow ◽  
Aortic Blood ◽  
Cox Inhibitor

This study’s aim was to determine the effect of hydroalcoholic extract ofM. cauliflora(HEMC) on vascular tension and blood pressure in rats. In ourin vitrostudies using precontracted isolated aortas from rats, HEMC and acetylcholine (positive control) induced relaxation only in vessels with endothelium. Pretreatment with L-NAME (NO synthase inhibitor) or ODQ (soluble guanylyl cyclase (sGC) inhibitor) abolished the HEMC-induced relaxation. The treatment with MDL-12,330A (adenylyl cyclase (AC) inhibitor) or diclofenac (COX inhibitor) reduced HEMC-induced vasorelaxation. The blockade of muscarinic andβ-adrenergic receptors (by atropine and propranolol, resp.) did not promote changes in HEMC-induced vasorelaxation. In ourin vivostudies, catheters were inserted into the right femoral vein and artery of anesthetized rats for HEMC infusion and the measurement of blood pressure, heart rate, and aortic blood flow. The intravenous infusion of HEMC produced hypotension and increased aortic blood flow with no changes in heart rate. These findings showed that HEMC induces endothelium-dependent vascular relaxation and hypotension with no alteration in heart rate. The NO/sGC/cGMP pathway seems to be the main cellular route involved in the vascular responsiveness.

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