Windkesselness of coronary arteries hampers assessment of human coronary wave speed by single-point technique

2008 ◽  
Vol 295 (2) ◽  
pp. H482-H490 ◽  
Author(s):  
Christina Kolyva ◽  
Jos A. E. Spaan ◽  
Jan J. Piek ◽  
Maria Siebes
Keyword(s):  
Coronary Arteries ◽  
Wave Speed ◽  
Single Point ◽  
Coronary Vessels ◽  
Distal Segment ◽  
Doppler Velocity ◽  
Healthy Human ◽  
Catheterization Laboratory ◽  
Before And After ◽  
Local Wave

A novel single-point technique to calculate local arterial wave speed ( SPc) has recently been presented and applied in healthy human coronary arteries at baseline flow. We investigated its applicability for conditions commonly encountered in the catheterization laboratory. Intracoronary pressure (Pd) and Doppler velocity ( U) were recorded in 29 patients at rest and during adenosine-induced hyperemia in a distal segment of a normal reference vessel and downstream of a single stenosis before and after revascularization. Conduit vessel tone was minimized with nitroglycerin. Microvascular resistance (MR) and SPc were calculated from Pd and U. In the reference vessel, SPc decreased from 21.5 m/s (SD 8.0) to 10.5 m/s (SD 4.1) after microvascular dilation ( P < 0.0001). SPc was substantially higher in the presence of a proximal stenosis and decreased from 34.4 m/s (SD 18.2) at rest to 27.5 m/s (SD 13.4) during hyperemia ( P < 0.0001), with a concomitant reduction in Pd by 20 mmHg and MR by 55.4%. The stent placement further reduced hyperemic MR by 26% and increased Pd by 26 mmHg but paradoxically decreased SPc to 13.1 m/s (SD 7.7) ( P < 0.0001). Changes in SPc correlated strongly with changes in MR ( P < 0.001) but were inversely related to changes in Pd ( P < 0.01). In conclusion, the single-point method yielded erroneous predictions of changes in coronary wave speed induced by a proximal stenosis and distal vasodilation and is therefore not appropriate for estimating local wave speed in coronary vessels. Our findings are well described by a lumped reservoir model reflecting the “windkesselness” of the coronary arteries.

scholarly journals Use of simultaneous pressure and velocity measurements to estimate arterial wave speed at a single site in humans

2006 ◽  
Vol 290 (2) ◽  
pp. H878-H885 ◽  
Author(s):  
Justin E. Davies ◽  
Zachary I. Whinnett ◽  
Darrel P. Francis ◽  
Keith Willson ◽  
Rodney A. Foale ◽  
...  
Keyword(s):  
Coronary Artery ◽  
Confidence Interval ◽  
Isosorbide Dinitrate ◽  
Wave Speed ◽  
Single Point ◽  
Point Method ◽  
Doppler Velocity ◽  
Velocity Measurements ◽  
Human Coronary Artery ◽  
Pressure And Velocity Measurements

It has not been possible to measure wave speed in the human coronary artery, because the vessel is too short for the conventional two-point measurement technique used in the aorta. We present a new method derived from wave intensity analysis, which allows derivation of wave speed at a single point. We apply this method in the aorta and then use it to derive wave speed in the human coronary artery for the first time. We measured simultaneous pressure and Doppler velocity with intracoronary wires at the left main stem, left anterior descending and circumflex arteries, and aorta in 14 subjects after a normal coronary arteriogram. Then, in 10 subjects, serial measurements were made along the aorta before and after intracoronary isosorbide dinitrate. Wave speed was derived by two methods in the aorta: 1) the two-site distance/time method (foot-to-foot delay of pressure waveforms) and 2) a new single-point method using simultaneous pressure and velocity measurements. Coronary wave speed was derived by the single-point method. Wave speed derived by the two methods correlated well ( r = 0.72, P < 0.05). Coronary wave speed correlated with aortic wave speed ( r = 0.72, P = 0.002). After nitrate administration, coronary wave speed fell by 43%: from 16.4 m/s (95% confidence interval 12.6–20.1) to 9.3 m/s (95% confidence interval 6.5–12.0, P < 0.001). This single-point method allows determination of wave speed in the human coronary artery. Aortic wave speed is correlated to coronary wave speed. Finally, this technique detects the prompt fall in coronary artery wave speed with isosorbide dinitrate.

COMPARATIVE STUDY FOR WAVE SPEED ESTIMATION AT A SINGLE AND TWO MEASUREMENT POINTS

2021 ◽  
pp. 2150048
Author(s):  
ASMA AYADI ◽  
WASSILA SAHTOUT ◽  
OLIVIER BALEDENT
Keyword(s):  
Regression Models ◽  
Wave Speed ◽  
Single Point ◽  
Area Formula ◽  
Reflected Waves ◽  
Cepstral Analysis ◽  
Contrast Magnetic Resonance ◽  
Local Wave ◽  
Blood Flow Velocities ◽  
Total Agreement

Local wave speed is a prognostic detector that allows the analysis of cardiovascular function. Objectives: This study compared wave speed ([Formula: see text] measurements at single-point and two-point techniques. Material and methods: [Formula: see text] were determined from the cepstral analysis of the blood flow velocities, which identified the arrivals times of reflected waves. The blood velocities waveforms were measured by using phase-contrast magnetic resonance (PCMR) for 20 subjects on young and old healthy subjects.  Local wave speed was estimated through the arrivals time of reflections waves ([Formula: see text] and the distance separating the measurement site to reflection area ([Formula: see text] or the distance separating the two measurement sites. Results: Our obtained results were in total agreement with reference values reported in the literature. Moreover, the detected results show that there is a high correlation ([Formula: see text]) between the two methods. Conclusion: The analysis of the wave speed variations with advancing age is also achieved out through different regression models.

scholarly journals On the Spectral and Polarimetric Signatures of a Bright Scatterer before and after Hardware Replacement

2021 ◽  
Vol 13 (5) ◽  
pp. 919
Author(s):  
Marco Gabella
Keyword(s):  
Low Noise ◽  
Low Noise Amplifiers ◽  
Doppler Velocity ◽  
Data Set ◽  
Differential Phase Shift ◽  
Spectral Signatures ◽  
Average Value ◽  
Before And After ◽  
Radar Calibration ◽  
Small Dispersion

A previous study has used the stable and peculiar echoes backscattered by a single “bright scatterer” (BS) during five winter days to characterize the hardware of C-band, the dual-polarization radar located at Monte Lema (1625 m altitude) in Southern Switzerland. The BS is the 90 m tall metallic tower on Cimetta (1633 m altitude, 18 km range). In this note, the statistics of the echoes from the BS were derived from other ten dry days with normal propagation conditions in winter 2015 and January 2019. The study confirms that spectral signatures, such as spectrum width, wideband noise and Doppler velocity, were persistently stable. Regarding the polarimetric signatures, the large values (with small dispersion) of the copolar correlation coefficient between horizontal and vertical polarization were also confirmed: the average value was 0.9961 (0.9982) in winter 2015 (January 2019); the daily standard deviations were very small, ranging from 0.0007 to 0.0030. The dispersion of the differential phase shift was also confirmed to be quite small: the daily standard deviation ranged from a minimum of 2.5° to a maximum of 5.3°. Radar reflectivities in both polarizations were typically around 80 dBz and were confirmed to be among the largest values observed in the surveillance volume of the Monte Lema radar. Finally, another recent 5-day data set from January 2020 was analyzed after the replacement of the radar calibration unit that includes low noise amplifiers: these five days show poorer characteristics of the polarimetric signatures and a few outliers affecting the spectral signatures. It was shown that the “historical” polarimetric and spectral signatures of a bright scatterer could represent a benchmark for an in-depth comparison after hardware replacements.

Wave speed in human coronary arteries is not influenced by microvascular vasodilation: implications for wave intensity analysis

2014 ◽  
Vol 109 (2) ◽  
Author(s):  
M. Cristina Rolandi ◽  
Kalpa Silva ◽  
Matthew Lumley ◽  
Timothy P. E. Lockie ◽  
Brian Clapp ◽  
...  
Keyword(s):  
Coronary Arteries ◽  
Wave Speed ◽  
Wave Intensity ◽  
Intensity Analysis ◽  
Wave Intensity Analysis

scholarly journals Measurement of renal tissue oxygenation with blood oxygen level-dependent MRI and oxygen transit modeling

2014 ◽  
Vol 306 (6) ◽  
pp. F579-F587 ◽  
Author(s):  
Jeff L. Zhang ◽  
Glen Morrell ◽  
Henry Rusinek ◽  
Lizette Warner ◽  
Pierre-Hugues Vivier ◽  
...  
Keyword(s):  
Tissue Oxygenation ◽  
Human Subjects ◽  
Blood Oxygen Level Dependent ◽  
Renal Tissue ◽  
Blood Oxygen ◽  
Oxygen Level ◽  
Blood Oxygen Level ◽  
Healthy Human ◽  
Bold Mri ◽  
Before And After

Blood oxygen level-dependent (BOLD) MRI data of kidney, while indicative of tissue oxygenation level (Po2), is in fact influenced by multiple confounding factors, such as R2, perfusion, oxygen permeability, and hematocrit. We aim to explore the feasibility of extracting tissue Po2 from renal BOLD data. A method of two steps was proposed: first, a Monte Carlo simulation to estimate blood oxygen saturation (SHb) from BOLD signals, and second, an oxygen transit model to convert SHb to tissue Po2. The proposed method was calibrated and validated with 20 pigs (12 before and after furosemide injection) in which BOLD-derived tissue Po2 was compared with microprobe-measured values. The method was then applied to nine healthy human subjects (age: 25.7 ± 3.0 yr) in whom BOLD was performed before and after furosemide. For the 12 pigs before furosemide injection, the proposed model estimated renal tissue Po2 with errors of 2.3 ± 5.2 mmHg (5.8 ± 13.4%) in cortex and −0.1 ± 4.5 mmHg (1.7 ± 18.1%) in medulla, compared with microprobe measurements. After injection of furosemide, the estimation errors were 6.9 ± 3.9 mmHg (14.2 ± 8.4%) for cortex and 2.6 ± 4.0 mmHg (7.7 ± 11.5%) for medulla. In the human subjects, BOLD-derived medullary Po2 increased from 16.0 ± 4.9 mmHg (SHb: 31 ± 11%) at baseline to 26.2 ± 3.1 mmHg (SHb: 53 ± 6%) at 5 min after furosemide injection, while cortical Po2 did not change significantly at ∼58 mmHg (SHb: 92 ± 1%). Our proposed method, validated with a porcine model, appears promising for estimating tissue Po2 from renal BOLD MRI data in human subjects.

A CADAVERIC STUDY ON CORONARY ARTERY VARIATIONS AND ITS CLINICAL `SIGNIFICANCE

2021 ◽  
pp. 20-22
Author(s):  
Sony Jhansi Priya ◽  
Sangeetha A ◽  
M. Sai Krishna
Keyword(s):  
Coronary Artery ◽  
Coronary Arteries ◽  
Left Coronary Artery ◽  
Coronary Vessels ◽  
Average Diameter ◽  
Cadaveric Study ◽  
Aortic Sinus ◽  
Clinical Procedures ◽  
Human Cadavers ◽  
The Right

Coronary artery variations are one of the commonest variations observed during clinical procedures. Normally, there are two main coronary arteries, the right coronary artery (RCA), left coronary artery (LCA).Left coronary artery gives two important branches left circumex artery (LCX) and left anterior descending (LAD) arteries. Knowledge about the coronary vessels and its variations are essential to clinicians to prevent untoward injury of vessels during any procedures. To study the morphology and variations of coronar Aim: y arteries by dissection. Materials and Methods: The present study was a cadaveric study which was conducted on 50 hearts obtained from adult human cadavers. Coronary arteries were dissected to see the origin, course and variations. The data was entered in Microsoft excel sheet and expressed in percentage. The Right Results: coronary artery branched out from the right aortic sinus and had an average diameter of 3.5mm. The left coronary artery arouse from left aortic sinus and had an average diameter of 4mm. LMCA divided into two branches in 60 percent, three branches in 30 percent and four branches in 06 percent of the hearts and direct branches from left aortic sinuus in 4 percent hearts.Based on the origin of Posterior descending or interventricular artery, Right dominance was observed in 68 percent, left dominance in 26 percent, and equal dominance in 06 percent of the hearts. Conclusion: Knowledge about the variations of coronary vessels is a prerequisite for clinicians to perform interventions of coronary vessels.

NECROTIZING ARTERITIS OF THE CORONARY VESSELS IN INFANCY

PEDIATRICS ◽  
1959 ◽  
Vol 23 (5) ◽  
pp. 914-926 ◽  
Author(s):  
Honor Munro-Faure
Keyword(s):  
Coronary Arteries ◽  
Coronary Vessels ◽  
Review Of The Literature ◽  
Diagnostic Problem ◽  
Gross Pathology

A case of necrotizing arteritis of the coronary vessels in a 4-month-old infant is described. Death was due to thrombosis of the aneurysmally dilated coronary arteries. A review of the literature yields a total of 19 cases of necrotizing arteritis in infancy, 12 of whom showed a similar gross pathology. Of these 12 at least 8 have presented with a similar symptomatology. Etiologic theories are discussed, and suggestions are made as to the possible management of infants presenting a similar diagnostic problem.

P873Plasma PCSK9 levels and atherosclerosis burden in the coronary arteries of patients undergoing coronary angiography

2019 ◽  
Vol 40 (Supplement_1) ◽  
Author(s):  
Y Panahi ◽  
M S Ghahrodi ◽  
M S Jamshir ◽  
M A Safarpour ◽  
M Pirro ◽  
...  
Keyword(s):  
Coronary Artery ◽  
Coronary Angiography ◽  
Coronary Arteries ◽  
Coronary Stenosis ◽  
Coronary Vessels ◽  
Cross Sectional Study ◽  
Cross Sectional ◽  
Vessel Disease ◽  
Coronary Calcifications ◽  
Triple Vessel Disease

Abstract Background Plasma PCSK9 levels, a novel and effective therapeutic target for CVD prevention, have been associated with CVD events irrespective of traditional risk factors. Whether PCSK9 levels predict coronary artery disease (CAD) burden and severity is a matter of dispute. Purpose To investigate the association between plasma PCSK9 levels and CAD characteristics, including number of major diseased vessels, severity of coronary stenosis, and the burden of coronary calcifications. Methods One hundred and one patients undergoing coronary angiography were recruited for this cross-sectional study. The number of major coronary diseased vessels was defined as the presence of ≥1 stenoses ≥50% in diameter of at least one major coronary artery. CAD severity was defined as either the absence of coronary stenosis (no-CAD), CAD<50% or CAD≥50% in one or more coronary arteries. The burden of coronary calcifications was estimated by angiography visual inspection and classified as absent, mild, moderate or severe. Results Coronary angiography showed single, double and triple vessel disease in 26 (25.7%), 23 (22.8%) and 21 (20.8%) patients, respectively; 20 (19.8%) and 11 (10.9%) pts had either minimal CAD (<50%) or normal angiographic findings. Also, calcifications were absent in 65 patients (64.4%), and mild, moderate and severe in 23 (22.8%), 11 (10.9%) and 2 (2%) patients, respectively. Plasma PCSK9 levels were significantly associated with age (rho=0.22, p=0.025) and SBP (rho=0.21, p=0.034), and were almost doubled in patients with chronic kidney disease (CKD) as compared to those without CKD [164.6 ng/mL (104.6–187.0) vs 94.8 ng/mL (86.8–114.9), p=0.006]. Among patients without CKD, those with CAD≥50% had higher plasma PCSK9 levels than those without [97.1 ng/mL (87.8–143.0) vs 83.2 ng/mL (73.4–102.6), p=0.04]. In the overall population, higher plasma PCSK9 levels were found in pts with triple vessel disease [165.7 ng/mL (121.3–180.5)] than in those with double/single vessel involvement [97.9 ng/mL (87.6–99.8) and 88.4 ng/mL (87.3–97.4), p<0.001 for both comparisons] or without CAD [87.5 ng/mL (74.3–114.9), p<0.001]. Also, a trend toward an increase of plasma PCSK9 levels was found with higher CAD severity [no-CAD: 87.5 ng/mL (74.3–114.9), CAD<50%: 89.1 ng/mL (78.9–105.3), CAD≥50%: 97.6 ng/mL (87.9–155.3), p=0.051], which turned significant after exclusion of CKD patients (p=0.042). Adjustment for age, sex, plasma LDL-cholesterol levels, statin use and CKD abolished the association between PCSK9 and CAD severity but not with the number of significantly diseased vessels and the burden of coronary calcifications. Conclusions Circulating PCSK9, whose plasma levels are significantly influenced by the presence of CKD, discriminates patients with significant coronary artery stenosis from those without CAD. In addition, both the number of diseased coronary vessels and total coronary calcifications are independently predicted by an elevated plasma PCSK9 level. Acknowledgement/Funding None

scholarly journals Association betweenFaecalibacterium prausnitziiand dietary fibre in colonic fermentation in healthy human subjects

2010 ◽  
Vol 104 (5) ◽  
pp. 693-700 ◽  
Author(s):  
Robin F. J. Benus ◽  
Tjip S. van der Werf ◽  
Gjalt W. Welling ◽  
Patricia A. Judd ◽  
Moira A. Taylor ◽  
...  
Keyword(s):  
Intestinal Microbiota ◽  
Dietary Fibre ◽  
Human Subjects ◽  
Healthy Human ◽  
Formulated Diets ◽  
Disease States ◽  
Before And After ◽  
Complex Ecosystem ◽  
Positive Correlations ◽  
Proportional Reduction

The intestinal microbiota are a complex ecosystem influencing the immunoregulation of the human host, providing protection from colonising pathogens and producing SCFA as the main energy source of colonocytes. Our objective was to investigate the effect of dietary fibre exclusion and supplementation on the intestinal microbiota and SCFA concentrations. Faecal samples were obtained from healthy volunteers before and after two 14 d periods of consuming formulated diets devoid or supplemented with fibre (14 g/l). The faecal microbiota were analysed using fluorescentin situhybridisation and SCFA were measured using GLC. There were large and statistically significant reductions in the numbers of theFaecalibacterium prausnitzii(P ≤ 0·01) andRoseburiaspp. (P ≤ 0·01) groups during both the fibre-free and fibre-supplemented diets. Significant and strong positive correlations between the proportion ofF. prausnitziiand the proportion of butyrate during both baseline normal diets were found (pre-fibre freer0·881,P = 0·001; pre-fibre supplementedr0·844,P = 0·002). A significant correlation was also found between the proportional reduction inF. prausnitziiand the proportional reduction in faecal butyrate during both the fibre-free (r0·806;P = 0·005) and the fibre-supplemented diet (r0·749;P = 0·013). These findings may contribute to the understanding of the association between fibre, microbiota and fermentation in health, during enteral nutrition and in disease states such as Crohn's disease.

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