The aortic reservoir-wave as a paradigm for arterial haemodynamics

This study examines the importance of vascular elasticity to arterial haemodynamics in a poikilothermic vertebrate. Pulsatile blood pressure, flow and vessel diameter were recorded at several locations within the arterial tree of the toad, Bufo marinus. We then determined the dynamic elastic modulus, the pulse wave velocity and the hydraulic impedance characteristics of the aorta. The relatively low heart rate and short arterial tree, and a pulse velocity of about 2.5ms−1, combine to give a transit time for the pressure pulse through aorta that is only 3% of the cardiac cycle. Consequently, wave propagation effects seen in mammals, such as peripheral amplification, distortion and secondary pressure peaks due to reflections, are not apparent. Instead, the aorta acts as a simple Windkessel and inflation by the heart occurs almost simultaneously throughout. Pressure waveforms are nearly identical at proximal and distal locations, and flow pulsatility is reduced progressively through the elastic aorta.

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P4.14 THE EFFECT OF GENDER AND BODY SIZE ON ARTERIAL HAEMODYNAMICS AT REST AND DURING EXERCISE

Artery Research ◽

10.1016/j.artres.2014.09.137 ◽

2014 ◽

Vol 8 (4) ◽

pp. 142

Author(s):

J. Middlemiss

Keyword(s):

Body Size ◽

Arterial Haemodynamics

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Thyroid and Hepatic Haemodynamic Alterations among Egyptian Children with Liver Cirrhosis

ISRN Gastroenterology ◽

10.5402/2012/595734 ◽

2012 ◽

Vol 2012 ◽

pp. 1-7 ◽

Cited By ~ 7

Author(s):

Zeinab A. El-Kabbany ◽

Rasha T. Hamza ◽

Ahmed S. Abd El Hakim ◽

Lamis M. Tawfik

Keyword(s):

Hepatic Artery ◽

Pulsatility Index ◽

Standard Deviation Score ◽

Resistance Index ◽

Thyroid Volume ◽

Thyroid Stimulating Hormone ◽

Inferior Thyroid Artery ◽

Egyptian Children ◽

Cirrhotic Patients ◽

Arterial Haemodynamics

Background. Alterations in thyroid hormones regulation and metabolism are frequently observed in patients with cirrhosis. Aims. To assess alterations in thyroid volume (TV), haemodynamics, and hormones in patients with cirrhosis and their relation to hepatic arterial haemodynamics, and disease severity. Methods. Forty cirrhotic patients were compared to 30 healthy subjects regarding TV, free triiodiothyronine (fT3), free tetraiodothyronine (fT4), thyroid stimulating hormone (TSH), and pulsatility and resistance indices in the inferior thyroid and hepatic arteries. Results. TV (P=0.042), thyroid volume standard deviation score (TVSDS, P=0.001), Inferior Thyroid Artery Pulsatility Index (ITAPI, P=0.001), Inferior Thyroid Artery Resistance Index (ITARI, P=0.041), Hepatic Artery Pulsatility Index (HAPI, P=0.029) and Hepatic Artery Resistance Index (HARI, P=0.035) were higher among cases being highest in Child-C patients. FT3 was lower in patients than controls (P=0.001) and correlated negatively with ITAPI (r=−0.71, P=0.021) and ITARI (r=−0.79, P=0.011). ITAPI and ITARI correlated directly with HAPI and HARI (r=0.62, P=0.03, and r=0.42, P=0.04, resp.). Conclusions. Thyroid is involved in the haemodynamic alterations of cirrhosis. Routine study of thyroid by Doppler and assessment of thyroid functions should be performed in patients with cirrhosis to offer proper treatment if needed.

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Input impedance of distributed arterial structures as used in investigations of underlying concepts in arterial haemodynamics

Medical & Biological Engineering & Computing ◽

10.1007/s11517-008-0413-0 ◽

2008 ◽

Vol 47 (2) ◽

pp. 143-151 ◽

Cited By ~ 22

Author(s):

Alberto Avolio

Keyword(s):

Input Impedance ◽

Arterial Haemodynamics

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Effect of meal induced splanchnic arterial vasodilatation on renal arterial haemodynamics in normal subjects and patients with cirrhosis

Gut ◽

10.1136/gut.43.6.843 ◽

1998 ◽

Vol 43 (6) ◽

pp. 843-848 ◽

Cited By ~ 13

Author(s):

T Iwao ◽

K Oho ◽

R Nakano ◽

M Yamawaki ◽

T Sakai ◽

...

Keyword(s):

Renal Artery ◽

Superior Mesenteric Artery ◽

Mesenteric Artery ◽

Pulsatility Index ◽

Doppler Ultrasonography ◽

Normal Subjects ◽

Haemodynamic Change ◽

Liquid Meal ◽

Arterial Circulation ◽

Arterial Haemodynamics

Aims—To investigate the relation between changes in splanchnic arterial haemodynamics and renal arterial haemodynamics in controls and patients with cirrhosis.Methods—Superior mesenteric artery pulsatility index (SMA-PI) and renal artery pulsatility index (R-PI) were measured using Doppler ultrasonography in 24 controls and 36 patients with cirrhosis. These measurements were repeated 30 minutes after ingestion of a liquid meal or placebo. Sixteen controls and 24 patients received the meal, and eight controls and 12 patients received placebo.Results—In the fasting condition, patients with cirrhosis had a lower SMA-PI (p<0.01) and a greater R-PI (p<0.01) compared with controls. Placebo ingestion had no effect on splanchnic and renal haemodynamics. In contrast, ingestion of the meal caused a notable reduction in SMA-PI (p<0.01, p<0.01) and an increase in R-PI (p<0.01, p<0.01) in controls and patients with cirrhosis. The meal induced haemodynamic change in SMA-PI was inversely correlated with that in R-PI in controls (t=−0.42, p<0.05) and in patients with cirrhosis (t=−0.29, p<0.05).Conclusions—Results support the hypothesis that renal arterial vasoconstriction seen in patients with cirrhosis is one of the kidney’s homoeostatic responses to underfilling of the splanchnic arterial circulation.

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