Sensitivity Analysis and Model Assessment: Mathematical Models for Arterial Blood Flow and Blood Pressure

2007 ◽  
Vol 8 (2) ◽  
pp. 94-108 ◽  
Author(s):  
Laura M. Ellwein ◽  
Hien T. Tran ◽  
Cheryl Zapata ◽  
Vera Novak ◽  
Mette S. Olufsen
Keyword(s):  
Blood Pressure ◽  
Sensitivity Analysis ◽  
Blood Flow ◽  
Mathematical Models ◽  
Arterial Blood Flow ◽  
Model Assessment ◽  
Arterial Blood

Increased vascular resistance in paralyzed legs after spinal cord injury is reversible by training

2002 ◽  
Vol 93 (6) ◽  
pp. 1966-1972 ◽  
Author(s):  
Maria T. E. Hopman ◽  
Jan T. Groothuis ◽  
Marcel Flendrie ◽  
Karin H. L. Gerrits ◽  
Sibrand Houtman
Keyword(s):  
Blood Pressure ◽  
Spinal Cord ◽  
Spinal Cord Injury ◽  
Blood Flow ◽  
Mean Arterial Pressure ◽  
Arterial Pressure ◽  
Vascular Resistance ◽  
Arterial Blood Flow ◽  
Arterial Blood ◽  
Cord Injury

The purpose of the present study was to determine the effect of a spinal cord injury (SCI) on resting vascular resistance in paralyzed legs in humans. To accomplish this goal, we measured blood pressure and resting flow above and below the lesion (by using venous occlusion plethysmography) in 11 patients with SCI and in 10 healthy controls (C). Relative vascular resistance was calculated as mean arterial pressure in millimeters of mercury divided by the arterial blood flow in milliliters per minute per 100 milliliters of tissue. Arterial blood flow in the sympathetically deprived and paralyzed legs of SCI was significantly lower than leg blood flow in C. Because mean arterial pressure showed no differences between both groups, leg vascular resistance in SCI was significantly higher than in C. Within the SCI group, arterial blood flow was significantly higher and vascular resistance significantly lower in the arms than in the legs. To distinguish between the effect of loss of central neural control vs. deconditioning, a group of nine SCI patients was trained for 6 wk and showed a 30% increase in leg blood flow with unchanged blood pressure levels, indicating a marked reduction in vascular resistance. In conclusion, vascular resistance is increased in the paralyzed legs of individuals with SCI and is reversible by training.

scholarly journals EFFECT OF DIFFERENT OCCLUSION PRESSURE ON PECULIARITIES OF MUSCLE BLOOD FLOW

2018 ◽  
Vol 1 (108) ◽  
pp. 2-8
Author(s):  
Kęstutis Bunevičius ◽  
Albinas Grunovas ◽  
Jonas Poderys
Keyword(s):  
Blood Pressure ◽  
Blood Flow ◽  
Arterial Blood Pressure ◽  
Arterial Blood Flow ◽  
Control Group ◽  
Reactive Hyperaemia ◽  
Occlusion Pressure ◽  
Arterial Blood ◽  
Flow Intensity ◽  
Blood Flow Intensity

Background. Occlusion pressure intensity influences the blood flow intensity. Immediately after the cuff pressure is released, reactive hyperaemia occurs. Increased blood flow and nutritive delivery are critical for an anabolic stimulus, such as insulin. The aim of study was to find which occlusion pressure was optimal to increase the highest level of post occlusion reactive hyperaemia. Methods. Participants were randomly assigned into one of the four conditions (n = 12 per group): control group without blood flow restriction, experimental groups with 120; 200 or 300 mmHg occlusion pressure. We used venous occlusion plethysmography and arterial blood pressure measurements. Results. After the onset of 120 and 200 mm Hg pressure occlusion, the blood flow intensity significantly decreased. Occlusion induced hyperaemia increased arterial blood flow intensity 134 ± 11.2% (p < .05) in the group with 120 mmHg, in the group with 200 mmHg it increased 267 ± 10.5% (p < .05), in the group with 300 mmHg it increased 233 ± 10.9% (p < .05). Applied 300 mmHg occlusion from the 12 minute diastolic and systolic arterial blood pressure decreased statistically significantly. Conclusions. Occlusion manoeuvre impacted the vascular vasodilatation, but the peak blood flow registered after occlusion did not relate to applied occlusion pressure. The pressure of 200 mmHg is optimal to impact the high level of vasodilatation. Longer than 12 min 300 mmHg could not be recommended due to the steep decrease of systolic and diastolic blood pressures.

Abstract P308: Rgs2 Promotes Uterine Blood Flow During Pregnancy

Hypertension ◽  
2017 ◽  
Vol 70 (suppl_1) ◽  
Author(s):  
Jennifer N Koch ◽  
Elizabeth A Owens ◽  
Shelby Dahlen ◽  
Jie Li ◽  
Patrick Osei Owusu
Keyword(s):  
Gene Expression ◽  
Blood Pressure ◽  
Blood Flow ◽  
G Protein ◽  
Arterial Blood Flow ◽  
G Protein Signaling ◽  
Protein Signaling ◽  
Uterine Blood Flow ◽  
Placental Perfusion ◽  
Arterial Blood

Regulators of G protein signaling (RGS) proteins are crucial in mediating vascular smooth muscle contraction via the regulation of heterotrimeric G proteins, affecting blood pressure and arterial blood flow. Previous studies by others and us showed that RGS2 deficiency augments vascular tone and impairs uterine blood flow (UBF) in non-pregnant mice, and that an Rgs2 loss-of-function mutation is linked to preeclampsia in humans; however, the mechanisms are unclear. Here, we tested the hypothesis that increased RGS2 expression and/or function facilitates placental perfusion by promoting vasodilation and UBF. We determined gene expression throughout pregnancy and post-partum period by real-time qPCR, while uterine blood flow and blood pressure were examined by ultrasound and carotid artery catheterization, respectively, under anesthesia. RGS2 expression decreased markedly by pregnancy day 10 (0.049 ± 0.013 vs. 0.023 ± 0.017) but returned to non-pregnancy level by day 15 (0.049 ± 0.013 vs. 0.041 ± 0.008,) in wild type mice. The pattern of changes in impedance to UBF mimicked gene expression profile in WT mice; in contrast, impedance remained elevated in Rgs2-/- mice at pregnancy day 15 (RI; WT: 0.516 ± 0.027, vs. RGS2-/-: 0.714 ± 0.020). Systemic blood pressure was similar between WT and Rgst2-/- mice at all stages of pregnancy. The results together indicate that RGS2 promotes uterine perfusion during pregnancy independently of its blood pressure effects. These findings are clinically relevant as selective targeting of G protein signaling could improve utero-placental hypoperfusion during pregnancy and prevent the development of pregnancy complications such as preeclampsia.

The selective closure of feline carotid arteriovenous anastomoses (AVAs) by GR43175

Cephalalgia ◽  
1989 ◽  
Vol 9 (9_suppl) ◽  
pp. 41-46
Author(s):  
Marion J Perren ◽  
Wasyl Feniuk ◽  
Patrick Pa Humphrey
Keyword(s):  
Blood Pressure ◽  
Blood Flow ◽  
Peripheral Resistance ◽  
Haemodynamic Effects ◽  
Arterial Blood Flow ◽  
Arteriovenous Anastomoses ◽  
Arterial Blood ◽  
Flow Through ◽  
Carotid Arterial ◽  
Dose Dependent

The haemodynamic effects of the selective 5-HT1-like agonist GR43175 have been compared with that of ergotamine in anaesthetized cats. Both GR43175 (30–1000 μg/kg intravenously) and ergotamine (0.3–30 μg/kg intravenously) caused a dose-dependent reduction in the proportion of cardiac output passing through arteriovenous anastomoses (AVAs). However, unlike GR43175, the effect of ergotamine (30 μg/kg intravenously) was associated with marked increases in diastolic blood pressure and total peripheral resistance. In further studies, the effect of GR43175 on the distribution of blood flow within the carotid bed has been examined. GR43175 caused a reduction in total carotid arterial blood flow which was entirely due to a reduction in flow through carotid AVAs. These results demonstrate that GR43175, unlike ergotamine, has a highly selective vasoconstrictor action on AVAs within the cranial circulation of anaesthetized cats. Such a mechanism may be important in its antimigraine activity.

Skeletal muscle arteriolar constriction to ANG II: evaluation of a myogenic component

1992 ◽  
Vol 263 (6) ◽  
pp. H1847-H1854 ◽  
Author(s):  
J. T. Fleming ◽  
G. L. Anderson ◽  
J. Chen
Keyword(s):  
Blood Pressure ◽  
Skeletal Muscle ◽  
Blood Flow ◽  
Pressure Rise ◽  
Arterial Blood Flow ◽  
Ang Ii ◽  
Cremaster Muscle ◽  
Abrupt Decrease ◽  
Arterial Blood ◽  
Slow Infusion

This study addressed the hypothesis that an increase in blood pressure contributes to the overall constrictive response of skeletal muscle arterioles to angiotensin II (ANG II). Diameters of second-order arterioles (2A) and third-order arterioles (3A) in the rat cremaster muscle were quantitated after intravenous administration of ANG II. Hindquarter blood pressure was either allowed to increase or was maintained at normal levels. Constriction of 3A to bolus injection of ANG II was the same whether hindquarter pressure increased or not. However, the total vascular constrictive response of the cremaster muscle (based on 2A blood flow) and of the entire hindquarter (based on iliac arterial blood flow) to bolus ANG II was greater when hindquarter pressure was held constant. During slow infusion of ANG II, 3A constriction was unaffected by an abrupt decrease or increase in hindquarter pressure. However, an abrupt reduction of hindquarter pressure caused a significant decline in hindquarter vascular resistance. Thus an increase in blood pressure, whether rapid or gradual, does not influence 3A constriction to ANG II. However, in the entire hindquarter, a rapid rise in blood pressure opposes constriction to ANG II, whereas a gradual pressure rise evokes a mechanism that enhances constrictive response to the peptide

scholarly journals Local and Systemic Cardiovascular Effects from Monochromatic Infrared Therapy in Patients with Knee Osteoarthritis: A Double-Blind, Randomized, Placebo-Controlled Study

2012 ◽  
Vol 2012 ◽  
pp. 1-9 ◽  
Author(s):  
Ru-Lan Hsieh ◽  
Wei-Cheng Liao ◽  
Wen-Chung Lee
Keyword(s):  
Blood Pressure ◽  
Blood Flow ◽  
Flow Velocity ◽  
Blood Flow Velocity ◽  
Cardiovascular Effects ◽  
Arterial Blood Flow ◽  
Controlled Study ◽  
Double Blind ◽  
Knee Oa ◽  
Arterial Blood

Infrared (IR) therapy is used for pain relief in patients with knee osteoarthritis (OA). However, IR’s effects on the cardiovascular system remain uncertain. Therefore, we investigated the local and systemic cardiovascular effects of monochromatic IR therapy on patients with knee OA in a double-blind, randomized, placebo-controlled study. Seventy-one subjects with knee OA received one session of 40 min of active or placebo monochromatic IR treatment (with power output of 6.24 W, wavelength of 890 nm, power density of 34.7 mW/cm2for 40 min, total energy of 41.6 J/cm2per knee per session) over the knee joints. Heart rate, blood pressure, and knee arterial blood flow velocity were periodically assessed at the baseline, during, and after treatment. Data were analyzed by repeated-measure analysis of covariance. Compared to baseline, there were no statistically significant group x time interaction effects between the 2 groups for heart rate (P=0.160), blood pressure (systolic blood pressure:P=0.861; diastolic blood pressure:P=0.757), or mean arterial blood flow velocity (P=0.769) in follow-up assessments. The present study revealed that although there was no increase of knee arterial blood flow velocity, monochromatic IR therapy produced no detrimental systemic cardiovascular effects.

scholarly journals Insulin resistance is associated with lower arterial blood flow and reduced cortical perfusion in cognitively asymptomatic middle-aged adults

2016 ◽  
Vol 37 (6) ◽  
pp. 2249-2261 ◽  
Author(s):  
Siobhan M Hoscheidt ◽  
J Mikhail Kellawan ◽  
Sara E Berman ◽  
Leonardo A Rivera-Rivera ◽  
Rachel A Krause ◽  
...  
Keyword(s):  
Insulin Resistance ◽  
Blood Flow ◽  
Arterial Blood Flow ◽  
Model Assessment ◽  
Middle Aged ◽  
Blood Draw ◽  
Arterial Blood ◽  
Increased Risk ◽  
Middle Aged Adults ◽  
Cortical Perfusion

Insulin resistance (IR) is associated with poor cerebrovascular health and increased risk for dementia. Little is known about the unique effect of IR on both micro- and macrovascular flow particularly in midlife when interventions against dementia may be most effective. We examined the effect of IR as indexed by the Homeostatic Model Assessment of Insulin Resistance (HOMA-IR) on cerebral blood flow in macro- and microvessels utilizing magnetic resonance imaging (MRI) among cognitively asymptomatic middle-aged individuals. We hypothesized that higher HOMA-IR would be associated with reduced flow in macrovessels and lower cortical perfusion. One hundred and twenty cognitively asymptomatic middle-aged adults (57 ± 5 yrs) underwent fasting blood draw, phase contrast-vastly undersampled isotropic projection reconstruction (PC VIPR) MRI, and arterial spin labeling (ASL) perfusion. Higher HOMA-IR was associated with lower arterial blood flow, particularly within the internal carotid arteries (ICAs), and lower cerebral perfusion in several brain regions including frontal and temporal lobe regions. Higher blood flow in bilateral ICAs predicted greater cortical perfusion in individuals with lower HOMA-IR, a relationship not observed among those with higher HOMA-IR. Findings provide novel evidence for an uncoupling of macrovascular blood flow and microvascular perfusion among individuals with higher IR in midlife.

scholarly journals Modelling Blood Pressure in Stenosed Coronary Arteries

2017 ◽  
Vol 61 (3) ◽  
pp. 242
Author(s):  
Viktor Szabó ◽  
Csaba Jenei ◽  
Gábor Halász
Keyword(s):  
Blood Pressure ◽  
Blood Flow ◽  
Coronary Arteries ◽  
Flow Model ◽  
Measurement Data ◽  
Arterial Blood Flow ◽  
Patient Specific ◽  
Arterial Blood ◽  
1D Model ◽  
Good Agreement

In this paper a 1D model is presented for the simulation of blood flow in stenosed coronary arteries. The model was developed by implementing a special boundary counditions in a previously published arterial blood flow model. The stenosis as well as the arterioles were modelled as linear resistances. Using patient-specific parameters, blood flow can be calculated for different inlet flow rates. The model was used to simulate blood pressure waveforms of 5 patients diagnosed with coronary stenosis. Simulation results show good agreement with measurement data.

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