Carotid Arterial Pressure Research Articles

Clinical application of full automatic animal experimental cabin of normobaric/hypobaric hypoxia and high carbon dioxide

Objective To explore the feasibility of the full automatic animal experimental cabin to establish the animal models in normobaric/hypobaric hypoxic and high carbon dioxide environment. Methods Sixty SPF-class male DS rats were divided into 2 groups, 20 for normobaric, hypoxic conditions and the other 40 for hypobaric, hypoxic conditions. For each group, the pulmonary arterial pressure and carotid arterial pressure indicators of rats were examined by using the physiological multi-detector, and the pulmonary vascular changes in the structure were observed. Results The normobaric/hypobaric hypoxic with high carbon dioxide environment can promote the formation of pulmonary hypertension and accelerate changes in pulmonary vascular remodeling, and promote the right ventricular hypertrophy. Conclusion Clinical applications showed that the animal experimental cabin has observed and controlled accurately. The result was safe, reliable and reproducible. The cabin can successfully establish the pulmonary hypertension model in normobaric/hypobaric hypoxic with high carbon dioxide environment, and in order to study the physiological mechanism of a variety of circulation and respiratory diseases caused by lack of oxygen, which provided an experimental technology platform for clinical research.

The use of diameter distension waveforms as an alternative for tonometric pressure to assess carotid blood pressure

Proper non-invasive assessment of carotid artery pressure ideally uses waveforms recorded at two anatomical locations: the brachial and the carotid artery. Calibrated diameter distension waveforms could provide a more widely applicable alternative for local arterial pressure assessment than applanation tonometry. This approach might be of particular use at the brachial artery, where the feasibility of a reliable tonometric measurement has been questioned. The aim of this study was to evaluate an approach based on distension waveforms obtained at the brachial and carotid arteries. This approach will be compared to traditional pulse pressures obtained through tonometry at both the carotid and brachial arteries (used as a reference) and the more recently proposed approach of combining tonometric readings at the brachial artery with linearly or exponentially calibrated distension curves at the carotid artery. Local brachial and carotid diameter distension and tonometry waveforms were recorded in 148 subjects (119 women; aged 19–59 years). The morphology of the waveforms was compared by the form factor and the root-mean-squared error. The difference between the reference carotid PP and the PP obtained from brachial and carotid distension waveforms was smaller (0.9 (4.9) mmHg or 2.3%) than the difference between the reference carotid PP and the estimates obtained using a tonometric and a distension waveform (−4.8 (2.5) mmHg for the approach using brachial tonometry and linearly scaled carotid distension, and 2.7 (6.8) mmHg when using exponentially scaled carotid distension waves). We therefore recommend to stick to one technique on both the brachial and the carotid artery, either tonometry or distension, when assessing carotid blood pressure non-invasively.

Noninvasive assessment of central and peripheral arterial pressure (waveforms): implications of calibration methods

Noninvasive estimation of central blood pressure (BP) from radial artery pressure waveforms is increasingly applied. We investigated the impact of radial artery waveform calibration on central BP assessment and calculated pressure amplification, with focus on the one-third rule used to estimate mean arterial BP (MAP). Pressure waveforms were noninvasively measured at the radial and carotid arteries in 1873 individuals (age 45.8+/-6.1 years). Radial and carotid artery waveforms were calibrated using brachial artery DBP and SBP, MAP estimated with the one-third rule and MAP estimated as brachial DBP along with 40% of brachial artery pulse pressure. Central SBP obtained via a transfer function was 123.5 +/- 15.7, 117.8 +/- 14.2 and 126.0 +/- 15.4 mmHg (mean +/- SD) following above-mentioned three calibration schemes, respectively. Using the same calibration schemes, carotid artery SBP was 131.4 +/- 15.2, 118.4 +/- 14.4 and 126.8 +/- 15.7 mmHg, respectively. Central-to-brachial amplification was 13.0 +/- 3.6 mmHg using second method as compared with 4.6 +/- 3.8 mmHg with third method. Brachial-to-radial amplification was actually negative (-6.3 +/- 4.5 mmHg) using second method, whereas 3.4 +/- 5.5 mmHg was found with third method. Both carotid artery SBP and central SBP obtained via a transfer function are highly sensitive to the calibration of the respective carotid artery and radial artery pressure waveforms. Our data suggest that the one-third rule to calculate MAP from brachial cuff BP should be avoided, especially when used to calibrate radial artery pressure waveforms for subsequent application of a pressure transfer function. Until more precise estimation methods become available, it is advisable to use 40% of brachial pulse pressure instead of 33% to assess MAP.

Central arterial pulse wave augmentation is greater in girls than boys, independent of height

Central arterial pulse wave augmentation, quantified by the augmentation index (AIx), is a key marker of arterial health, an important contributor to cardiac afterload and is significantly greater in older women than men. We measured carotid AIx in 8-year-old children to examine the influences of sex, height and arterial stiffness on central arterial pulse wave augmentation Four hundred and five children (age 8.0 +/- 0.1 years, 49% girls) had anthropometry, brachial systolic and diastolic blood pressure, heart rate and carotid artery pressure waveforms (by applanation tonometry), diastolic diameter and distensibility assessed. Carotid AIx was significantly higher in girls than boys (-11.7 +/- 8.1 versus -16.5 +/- 9.3%, respectively, P < 0.001). Boys and girls had similar height (129 +/- 6 versus 128 +/- 6 cm), systolic blood pressure (100 +/- 7 versus 101 +/- 7 mmHg), diastolic blood pressure (59 +/- 6 versus 60 +/- 5 mmHg) and heart rate (80 +/- 10 versus 82 +/- 10 bpm). Carotid diastolic diameter was smaller in girls than boys (0.45 +/- 0.03 versus 0.47 +/- 0.04 cm, P < 0.001). The sex difference in AIx remained significant after adjustment for height, heart rate, blood pressure, diastolic diameter and birth weight. The time to the onset of the reflected wave was shorter in girls (155 +/- 19 versus 163 +/- 18 ms, P < 0.001). Girls had greater carotid artery distensibility (6.2 +/- 1.8 versus 5.8 +/- 1.5% per 10 mmHg, P = 0.016), suggesting lower regional carotid artery stiffness. Greater pulse wave augmentation in prepubertal girls results from earlier wave reflection and is independent of height, carotid artery diameter and stiffness. When combined with age-related changes in arterial compliance, this may contribute to adverse cardiovascular outcomes in older women.

Effet de Mitragyna ciliata (MYTA) sur le système cardiovasculaire de rat

In this study, we evaluate the influence of a methanolic extract of Mitragyna ciliata (MYTA) [Rubiaceae] on the mechanics of isolated rat heart, thanks to improved Langerdorff’s device and carotid arterial pressure of rabbits with Ludwig’s device. MYTA, in concentrations ranging from 10−5 mg/ml to 5 × 10 mg/ml induces a drop in blood pressure with inotropic effect that varies from 0 to 35 ± 0.89% increase in concentrations ranging from 10−5 mg/ml at 5 × 10−1 mg/ml and a very high concentration of 1 mg/ml stops the heart with a magnitude of more than 50 ± 1.29% increase compared with the control. It also induces a dose-dependent negative chronotropic effect decreasing to 48 ± 0.79% before vanishing with the concentration of 1 mg/ml. In addition, MYTA gradually regulates the activity of cardiac arrhythmia induced by atropine and hypothermia. Thus, MYTA strengthens, regulates, and slows the activity of heart. MYTA induces dose-dependent hypotension ranging from 140 mmHg (normal) to 129 mmHg for a dose of 40-mg/kg body weight.

Aortic Arch Surgery With a Single Centrifugal Pump for Selective Cerebral Perfusion and Systemic Circulation

In aortic arch surgery, two pumps are required for systemic perfusion and selective cerebral perfusion (SCP). A new technique with a single centrifugal pump for systemic perfusion and SCP was developed and its efficacy and safety evaluated. This technique was adopted for total arch replacement in 22 consecutive patients with true aneurysms (13) and aortic dissection (nine) from January 2005 to January 2008. Cerebral perfusion lines branched from the main perfusion line. During SCP, right radial arterial pressure was maintained at 50 mm Hg and left common carotid arterial pressure at 60 mm Hg, and the regional cerebral oxygen saturation (rSO(2)) values were maintained at approximately >80% of the baseline value. Two operative deaths (9%) occurred due to pneumonia and hemorrhage in the left lung, respectively. Stroke occurred in one patient (5%). This simple circuit system can thus be easily and safely applied for aortic arch surgery.

Measurement of arterial distensibility and compliance to assess prognosis

Background and aim Total arterial compliance (TAC) reflects arterial function in the entire systemic circulation while distensibility coefficient (DC) is an estimate of local arterial compliance obtained from large elastic arteries. There are few studies relating TAC or DC to outcome. We sought whether DC or TAC predicted outcome in a primary prevention cohort with a spectrum of cardiovascular risk. Methods Clinical data including blood pressure (BP) and diabetes mellitus (DM) were obtained and Framingham 10-year risk was calculated in 719 primary prevention patients (373 men; age 55 ± 11 years). TAC was calculated from applanation tonometry using the pulse-pressure method, 2D-echocardiography and Doppler, and DC was derived from 2D measurements of the common carotid artery and pulse pressure (PP). Cox regression analysis was performed to determine correlates of outcome. Results There were 42 deaths (5.8%) and 114 cardiovascular admissions (15.8%) over 57 months. The independent correlates of mortality were Framingham 10-year risk (HR = 1.69; p < 0.0001) and DC (HR = 0.54; p = 0.02) (model chi-square 24.52; p < 0.0001) but not TAC. The independent predictors of the composite outcome of either death or admission for cardiovascular causes were Framingham 10-year risk (HR = 1.28; p = 0.001) and TAC (HR = 0.75; p = 0.006) (model chi-square 21.43; p < 0.0001) but not DC. Conclusions Measurement of arterial function is independently correlated with outcome in patients with varying degrees of cardiovascular risk, and different aspects identify fatal and non-fatal events. In addition, measurement of TAC and DC adds incremental benefit to Framingham risk scores alone in patients with intermediate cardiovascular risk.

Jugular venous pooling during lowering of the head affects blood pressure of the anesthetized giraffe

How blood flow and pressure to the giraffe's brain are regulated when drinking remains debated. We measured simultaneous blood flow, pressure, and cross-sectional area in the carotid artery and jugular vein of five anesthetized and spontaneously breathing giraffes. The giraffes were suspended in the upright position so that we could lower the head. In the upright position, mean arterial pressure (MAP) was 193 +/- 11 mmHg (mean +/- SE), carotid flow was 0.7 +/- 0.2 l/min, and carotid cross-sectional area was 0.85 +/- 0.04 cm(2). Central venous pressure (CVP) was 4 +/- 2 mmHg, jugular flow was 0.7 +/- 0.2 l/min, and jugular cross-sectional area was 0.14 +/- 0.04 cm(2) (n = 4). Carotid arterial and jugular venous pressures at head level were 118 +/- 9 and -7 +/- 4 mmHg, respectively. When the head was lowered, MAP decreased to 131 +/- 13 mmHg, while carotid cross-sectional area and flow remained unchanged. Cardiac output was reduced by 30%, CVP decreased to -1 +/- 2 mmHg (P < 0.01), and jugular flow ceased as the jugular cross-sectional area increased to 3.2 +/- 0.6 cm(2) (P < 0.01), corresponding to accumulation of approximately 1.2 l of blood in the veins. When the head was raised, the jugular veins collapsed and blood was returned to the central circulation, and CVP and cardiac output were restored. The results demonstrate that in the upright-positioned, anesthetized giraffe cerebral blood flow is governed by arterial pressure without support of a siphon mechanism and that when the head is lowered, blood accumulates in the vein, affecting MAP.

Role of cardiopulmonary and carotid sinus baroreceptors in regulating renal sympathetic nerve activity during water immersion in conscious dogs

The aim of the present study was to investigate how loading of cardiopulmonary baroreceptors induced by water immersion (WI) modifies baroreflex control of renal sympathetic nerve activity (RSNA) in conscious dogs. Nine dogs were chronically instrumented for measuring carotid sinus nerve activity (CSNA), RSNA, carotid arterial (Pca), and central venous (Pcv) pressures. The stimulus-response relationships of Pca-CSNA and Pca-RSNA were determined simultaneously in the same dog by changing Pca using rapid intravenous infusions vasoactive drugs during pre-WI and WI. WI increased central venous pressure significantly (P < 0.05) by 10.4 mmHg. WI shifted the Pca-RSNA curve acutely leftward compared with the pre-WI period, which was associated with significant (P < 0.05) decreases in the saturation pressure by 39.0 mmHg and operating range by 43.1 mmHg. WI relocated the operating pressure to near the saturation pressure, where the gain was low. The Pca-CSNA curve obtained during WI was identical to that obtained during pre-WI period. These results suggest that the shift in baroreflex control of RSNA could be attributed to the inhibitory influence of the cardiopulmonary mechanoreceptor loading and not by the resetting of carotid baroreceptors per se.

Selective antegrade cerebral perfusion at two different temperatures compared to hypothermic circulatory arrest - an experimental study in the pig with microdialysis

Hypothermic arrest and selective antegrade cerebral perfusion (SACP) is widely used during aortic arch surgery. The microdialysis technique monitors biomarkers of cellular metabolism and cellular integrity over time. In this study, the cerebral changes during hypothermic circulatory arrest (HCA) at 20 degrees C and HCA with SACP at two different temperatures, 20 and 28 degrees C, were monitored. Twenty-three pigs were divided into three groups. A microdialysis probe was fixated into the forebrain. Circulatory arrest started at a brain and body temperature of 20 degrees C or 28 degrees C. Arrest with/without cerebral perfusion (flow 10 ml/kg, max carotid artery pressure 70 mmHg) lasted for 80 min followed by reperfusion and rewarming during 40 min and an observation period of 120 min. The microdialysis markers were registered at six time-points. The lactate/pyruvate ratio (L/P ratio) and the lactate/glucose ratio (L/G ratio) increased significantly (P<0.05), during arrest, in the HCA group. The largest increase of glycerol was found in the group with tepid cerebral perfusion (28 degrees C) and the HCA group (P<0.05). This study supports the use of SACP over arrest. It also suggests that cerebral metabolism and cellular membrane integrity may be better preserved with SACP at 20 degrees C compared to 28 degrees C.

Blockade of PGHS-2 inhibits the hypothalamus-pituitary-adrenal axis response to cerebral hypoperfusion in the sheep fetus

Decreases in fetal blood pressure stimulate homeostatic stress responses that help return blood pressure to normal levels. Fetal hypothalamus-pituitary-adrenal (HPA) axis responses to hypotension are mediated by chemoreceptor and baroreceptor reflexes and ischemia of the fetal central nervous system. Indomethacin, a nonselective inhibitor of prostaglandin endoperoxide synthase (PGHS)-1 and -2, attenuates the HPA response to hypotension in the fetus. The present study was designed to test the hypothesis that selective inhibition of PGHS-2 also inhibits the HPA response to cerebral hypoperfusion. We studied 13 chronically catheterized fetal sheep (126-136 days gestation). Five fetal sheep were subjected to intracerebroventricular infusion of nimesulide (0.01 mg/day), a specific inhibitor of PGHS-2, and eight were treated with vehicle (DMSO in water) for 5 days. Each fetus was subjected to a 10-min period of brachiocephalic occlusion, which decreased carotid arterial pressure approximately 75% and reflexively increased fetal plasma concentrations of ACTH, POMC, cortisol, and femoral arterial pressure, and decreased fetal heart rate. Nimesulide significantly inhibited the ACTH response to the BCO, while significantly augmenting the reflex cardiovascular response and altering fetal heart rate variability consistent with increased sympathetic nervous system activity. The results of this study demonstrate that the activity of PGHS-2 in the brain is a necessary component of the fetal HPA response to cerebral hypoperfusion in the late-gestation fetal sheep. These results are consistent with those of recent study, in which we demonstrated that the preparturient increase in fetal ACTH secretion depends upon PGHS-2 activity within the fetal brain.

Stochastic approach to estimate the arterial pressure

The aim of this paper is to illustrate the application of a stochastic approach to estimate the human common carotid arterial pressure. The analysis took into account the possible random uncertainties of the problem inputs such as geometric information and mechanical model parameters so that it is called a probabilistic parametric approach. Based on the only available information reported in literature, entropy maximum principle was used to develop probabilistic density functions for every random variable. In addition, in vivo human experimental data were considered for the determination of the so-called mean or deterministic model. Furthermore, numerical simulations of Monte Carlo were carried out involving the dispersion of all the uncertain parameters. Results showed that uncertainty of 5% led to error up to 20% in the arterial pressure estimation. Convergence was proved and a region with a confidence probability of 95% was constructed to allow the prediction of the random response of the arterial pressure. Eventually, we managed numerous calculations to analyze the influence of each random variable of the problem inputs over the arterial pressure evolution.

CHAPTER 7 INFLUENCE OF PaCO2 ON INTERNAL CAROTID ARTERY PRESSURE AND rCBF DURING CAROTID CLAMPING

Acta Neurologica ScandinavicaVolume 49, Issue S52 p. 47-51 CHAPTER 7 INFLUENCE OF PaCO2 ON INTERNAL CAROTID ARTERY PRESSURE AND rCBF DURING CAROTID CLAMPING First published: April 1973 https://doi.org/10.1111/j.1600-0404.1973.tb02269.xAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat Volume49, IssueS52April 1973Pages 47-51 RelatedInformation

Use of a common carotid artery for arterial inflow in extracorporeal circulation: side-related flow and pressure profile

Objectives: Aim of the study was to evaluate the profile of flow and pressure in carotid arteries used for arterial inflow during extracorporeal circulation with emphasis on possible side-related differences.

Hemodynamic and Biochemical Changes during Total Hepatic Vascular Exclusion in Dogs

Twelve healthy Beagles were divided into 3 groups of 4 dogs each. To compare 2 methods of total hepatic vascular exclusion (THVE), we investigated the hemodynamic changes during THVE and assessed the influences on hepatic, renal and pancreatic biochemistry and the complications after THVE. In Group A, the thoracic aorta, hepatic pedicle and prehepatic and posthepatic caudal vena cava were occluded for 20 min, while in Group B, the celiac and cranial mesenteric arteries, hepatic pedicle and prehepatic and posthepatic caudal vena cava were occluded for 20 min. In Group C, a sham operation was performed. The arterial, venous and portal venous pressures and serum biochemistry parameters were measured before and during THVE and for 30 min after reperfusion. The carotid arterial pressure did not change in Group A during THVE, but decreased in Group B. The femoral and portal venous pressures in Group B increased significantly during THVE compared with those in Group C. With the exception of alanine aminotransferase, the serum biochemical profiles remained unchanged after the operation. For 7 days after the operation, no complications were observed in any of the dogs. In conclusion, occlusion of thoracic aorta, hepatic pedicle and prehepatic and posthepatic caudal vena cava is a feasible and safe method of hepatic vascular occlusion. This technique appears to be effective for canine hepatic surgery, such as removal of a large right-divisional hepatic tumor and attenuation of intrahepatic portosystemic shunt.

持久性運動習慣および月経周期が若年女性の頸動脈スティフネスに与える影響

Increased carotid arterial stiffness is associated with a risk factor of congestive heart failure. Thus factors that affect carotid arterial stiffness are of both physiological and clinical interest. The purpose of the present study was to examine the effects of regular aerobic exercise and menstrual cycle on carotid arterial stiffness in young female. The carotid β-stiffness index, an index of carotid arterial stiffness, was assessed in eight young female athletes (20.5 ± 0.4 years) and ten young female control subjects (21.3 ± 0.7 years). The carotid β-stiffness index was determined using ultrasound images of the common carotid artery with simultaneous recording of carotid arterial blood pressure by applanation tonometry. There was no difference in carotid β-stiffness index between the control and the athlete group both at the early follicular and the pre-ovulation phase of the menstrual cycle. On the other hand, the carotid β-stiffness index decreased from the early follicular phase to the pre-ovulation phase both in the control and the athlete group. These results suggest that carotid arterial stiffness in young females is not affected by regular aerobic exercise, but changes with the menstrual cycle, irrespective of exercise status.

Determining carotid artery pressure from scaled diameter waveforms: comparison and validation of calibration techniques in 2026 subjects

Calibrated diameter distension waveforms could provide an alternative for local arterial pressure assessment more widely applicable than applanation tonometry. We compared linearly and exponentially calibrated carotid diameter waveforms to tonometry readings. Local carotid pressures measured by tonometry and diameter waveforms measured by ultrasound were obtained in 2026 subjects participating in the Asklepios study protocol. Diameter waveforms were calibrated using a linear and an exponential calibration scheme and compared to measured tonometry waveforms by examining the mean root-mean-squared error (RMSE), carotid systolic blood pressure (SBPcar) and augmentation index (AIx) of calibrated and measured pressures. Mean RMSE was 5.2(3.3) mmHg (mean(stdev)) for linear and 4.6(3.6) mmHg for exponential calibration. Linear calibration yielded an underestimation of SBPcar by 6.4(4.1) mmHg which was strongly correlated to values of brachial pulse pressure (PPbra) (R = 0.4, P < 0.05). Exponential calibration underestimated true SBPcar by 1.9(3.9) mmHg, independent of PPbra. AIx was overestimated by linear calibration by 1.9(10.1)%, the difference significantly increasing with increasing AIx (R = 0.25, P < 0.001) and by exponential calibration by 5.4(10.6)%, independently of the value of AIx. Properly calibrated diameter waveforms offer a viable alternative for local pressure estimation at the carotid artery. Compared to linear calibration, exponential calibration significantly improves the pressure estimation.

Novel haemodynamic effects of recombinant C5a and C5a des Arg in rats and mice

Sepsis is defined as the body's response to an infection, characterised by an overwhelming release of inflammatory mediators, haemodynamic changes and cardiac dysfunction. Complement factor 5a (C5a) is produced in sepsis and has been shown to play a major role in the pathogenesis of sepsis and more recently, in septic cardiomyopathy. Conflicting data exists regarding the effect of C5a and its degradation product C5a des Arg on blood pressure. Therefore, the aim of this study was to determine the haemodynamic effects of recombinant rat and mouse C5a and C5a des Arg in their respective species. A catheter was inserted into the common carotid artery and mean arterial pressure (MAP) was measured using a PowerLab® data acquisition system with LabChart® analysis software. At various time points, blood was obtained from the tail vein for neutrophil counts and serum TNF-α concentrations were analysed using an ELISA. An intravenous injection of 50 μg/kg of rat C5a into rats resulted in both transient hypertension and neutropenia. This change in MAP was dose-dependent, where no effect was observed with 5 μg/kg. Pre-treatment of rats with 1 mg/kg of indomethacin prevented the hypertensive effect of 50 μg/kg of rat C5a. Further, 50 μg/kg of mouse C5a injected intravenously in wildtype mice resulted in a similar hypertensive response, but had no effect on MAP in C5a receptor knockout mice. To demonstrate that the blood pressure changes were not due to endotoxin, rat C5a was boiled at 100 °C, and this abolished the rise in MAP in rats. Experiments are currently underway to determine the effects of rat and mouse C5a des Arg in rats and mice respectively. In conclusion, our study is the first to demonstrate that recombinant rat and mouse C5a cause transient hypertension in their respective species. These findings are pivotal to the understanding of C5a in the pathogenesis of sepsis and septic cardiomyopathy.

Blood pressure waveform analysis by means of wavelet transform

The assessment of cardiovascular function by means of arterial pulse wave analysis (PWA) is well established in clinical practice. PWA is applied to study risk stratification in hypertension, with emphasis on the measurement of the augmentation index as a measure of aortic pressure wave reflections. Despite the fact that the prognostic power of PWA, in its current form, still remains to be demonstrated in the general population, there is general agreement that analysis and interpretation of the waveform might provide a deeper insight in cardiovascular pathophysiology. We propose here the use of wavelet analysis (WA) as a tool to quantify arterial pressure waveform features, with a twofold aim. First, we discuss a specific use of wavelet transform in the study of pressure waveform morphology, and its potential role in ascertaining the dynamics of temporal properties of arterial pressure waveforms. Second, we apply WA to evaluate a database of carotid artery pressure waveforms of healthy middle-aged women and men. Wavelet analysis has the potential to extract specific features (wavelet details), related to wave reflection and aortic valve closure, from a measured waveform. Analysis showed that the fifth detail, one of the waveform features extracted applying the wavelet decomposition, appeared to be the most appropriate for the analysis of carotid artery pressure waveforms. What remains to be assessed is how the information embedded in this detail can be further processed and transformed into quantitative data, and how it can be rendered useful for automated waveform classification and arterial function parameters with potential clinical applications.

Morphological But Not Functional Changes of the Carotid Artery Are Associated With the Extent of Coronary Artery Disease in Patients With Preserved Left Ventricular Function

The atherosclerotic process is associated with both morphological and functional changes in the carotid artery. We evaluated the relationship between these parameters of the carotid artery and the extent of coronary artery disease (CAD) in patients with preserved left ventricular function. The study population consisted of 104 stable patients with CAD who had preserved left ventricular function (left ventricular ejection fraction >or=45%). All patients underwent carotid ultrasound for evaluation of carotid artery plaque score defined by the sum of plaque thickness, maximum percent area stenosis, and carotid arterial stiffness index beta calculated by a combination of changes in carotid arterial diameter and blood pressure. Plaque score and percent area stenosis correlated with the extent of CAD defined as the number of diseased coronary vessels (P<0.001 and 0.002, respectively), but arterial stiffness beta did not (P=0.39). Using logistic regression analyses adjusting for confounding coronary risk factors and arterial stiffness beta, plaque score and percent area stenosis were independently correlated with multivessel CAD (P=0.001 and 0.004, respectively). Carotid artery plaque burden, but not arterial stiffness, is associated with the extent of CAD, suggesting morphological rather than functional changes in the carotid artery may be a more accurate predictor of the extent of CAD and multivessel CAD independent of left ventricular function.