Common Carotid Artery Pulsatility Index Research Articles

The Association of Carotid Plaque Size, Carotid Intima-Media Thickness, Resistive Index, and Pulsatility Index With Acute Ischemic Stroke.

Carotid atherosclerosis is an important etiological factor for ischemic stroke. Early carotid lesion detection may prevent further strokes. Doppler ultrasound measures carotid artery blood flow, intima-media thickness, stenosis, plaques, and lumen and wall changes. The objective of this study is to determine the association of carotid plaque size (CPS), carotid intima-media thickness (CIMT), resistive index (RI), and pulsatility index (PI) with acute ischemic stroke. A total of 60 participants were taken, including 30 cases and 30 age- and sex-matched controls. Patients with acute ischemic stroke were included as cases and age- and sex-matched healthy volunteers were included as controls. A carotid duplex study was done in both groups, and the findings were compared. The mean age of the ischemic stroke cases was 63.33±10.79 years; more than half were aged >60 years. Male patients were 73.3% and female patients were 26.7% of the cases. Age and gender were statistically similar (p>0.05) in groups (cases and controls). The plaques were homogenous in 30% of patients, calcified in 26.7%, and mixed in 6.7%. About 36.6% of patients did not have any plaque.CPS was greater among cases than controls in the right and left internal and left common carotid arteries; however, it was not statistically significant (p>0.05). The mean CIMT was 0.79±0.10 mm on the right side and 0.90±0.17 mm on the left side among cases. CIMT was significantly higher in the cases group than in the controls (p<0.05). The mean RI was significantly greater in the left common carotid artery (CCA) among the cases than in the controls (p<0.05). Patients aged over 60 years had significantly higher RI and PI values in the left internal carotid artery (ICA) compared to the younger cases (p<0.05). Smoking history had a significant association with left CCA RI and PI values (p<0.05). However, RI, PI, CPS, and CIMT among cases were similar in different groups like diabetic, non-diabetic, hypertensive, and non-hypertensive patients (p>0.05). CIMT was significantly thicker among the patients with ischemic stroke compared to the control group. RI in the left CCA was significantly greater among the stroke patients than in the control group. The age of the patient and smoking habithad an association with RI and PI values. Most of the parameters were found to be significant on the left side, suggesting carotid atherosclerosis may not be symmetrical. A large-scale further study is needed to see the association of these variables with ischemic stroke patients.

Differences in Carotid Artery Geometry and Flow Caused by Body Postural Changes and Physical Exercise.

Different body postures and physical exercises may lead to changes in arterial geometry and hemodynamics, which may be associated with the distribution of atherosclerosis lesions. This study was aimed at investigating potential geometric and hemodynamic changes of the carotid bifurcation in different body postures and after high-intensity interval training (HIIT) workouts. Three-dimensional vascular ultrasound (3DVUS) and Doppler ultrasound images were acquired for 21 healthy participants (aged 29 ± 6 y, 14 men and 7 women) in different body postures (sitting and three sleeping postures [supine, left lateral and right lateral]) and after physical exercises. The common carotid artery (CCA) and internal carotid artery (ICA) diameters of the left carotid artery were found to increase significantly from supine to left lateral (both p <0.05). CCA diameters (p < 0.05) and ICA/CCA diameter ratio (p < 0.01) of the left carotid artery changed significantly from supine to sitting. Significant differences in CCA peak systolic velocity (CCA PSV, p < 0.001), CCA end-diastolic velocity (CCA EDV, p < 0.001), CCA pulsatility index (CCA PI, p < 0.001) and maximum velocity-based wall shear stress at the CCA (WSS(max) at the CCA, p < 0.001) were identified in different postures. After physical exercises, significant increases were observed in the CCA diameter (p < 0.001), CCA PSV (p < 0.001), ICA PSV (p < 0.05), WSS(max) at the CCA (p < 0.001) and WSS(max) at the ICA (p < 0.05), as were significantly lower values of the CCA EDV (p < 0.01) and ICA/CCA PSV ratio (p < 0.05). Side-to-side differences were also detected in different postural change scenarios and after physical exercise; more significant differences were found to occur only in the left-sided carotid artery. Significant differences were identified under postural change and after physical exercise among healthy adults, suggesting that daily activity has an effect on the carotid bifurcation. These changes may be associated with formation and development of carotid atherosclerosis. Moreover, these side differences might be severe for patients and worth further attention in clinical practice.

Intima-Media Thickness and Pulsatility Index of Common Carotid Arteries in Acute Ischaemic Stroke Patients with Diabetes Mellitus.

Ultrasonographic parameters such as the common carotid artery (CCA) pulsatility index (PI) and CCA intima-media thickness (IMT) have been associated with an increased mortality and risk of recurrent stroke, respectively. We hypothesized that these ultrasonographic parameters may be useful for monitoring diabetic patients after an acute stroke. We analysed retrospective data of consecutive acute ischaemic stroke patients from the ASTRAL registry who underwent pre-cerebral ultrasonographic evaluation within 7 days of symptom onset. We compared clinical, demographic, radiological and ultrasonographic parameters in diabetic versus non-diabetic patients (univariable and multivariable analyses) and the association of these parameters with CCA PI and CCA IMT. We analysed 1507 carotid duplex ultrasound examinations from patients with a median age of 74 years. Cardiovascular co-morbidities, including hypertension, hypercholesterolemia, obstructive sleep apnoea syndrome, higher body-mass index (BMI) and peripheral artery disease, were associated with diabetes mellitus (DM). Diabetics were more often under antiplatelet therapy and had atrial fibrillation at admission. Diabetic patients showed an increased CCA PI and IMT in line with more atherosclerotic changes on acute CTA compared to non-diabetic patients. Taking IMT as the dependent variable in a second analysis, DM, higher age, hypertension, smoking and CCA PI were associated with higher IMT. Taking CCA PI as the dependent variable in a third analysis, DM, higher age and higher NIHSS at admission were associated with higher CCA PI values. Increased IMT was also associated with higher PI. We show that CCA PI and IMT are higher in diabetic patients in the first week after an initial stroke.

Impact of acute changes in blood pressure and arterial stiffness on cerebral pulsatile haemodynamics in young and middle-aged adults.

What is the central question of this study? Does cerebrovascular pulsatility respond differently to acute increases in arterial stiffness in middle-aged compared with young adults? What is the main finding and its importance? Compared with young adults, middle-aged adults exhibited similar changes in cerebral pulsatile damping despite attenuated changes in carotid diameter and cerebrovascular pulsatility during blood pressure-dependent, but not blood pressure-independent, increases in large artery stiffness. Acute manipulation of arterial stiffness through interventions that increase sympathetic activity might provoke cerebral pulsatility and damping and reveal whether cerebrovascular haemodynamics respond differently to transient elevations in arterial stiffness in middle-aged compared with young adults. We compared cerebral pulsatility and damping in middle-aged versus young adults during two different sympathetic interventions [cold pressor test (CP) and lower-body negative pressure (LBNP)] that increase arterial stiffness acutely. Cerebrovascular haemodynamics were assessed in 15 middle-aged (54 ± 7years old; 11 female) and 15 sex-matched young adults (25 ± 4years old) at rest and during the CP test (4min, 6.4 ± 0.8°C) and LBNP (6min, -20mmHg). Mean blood pressure was measured continuously via finger photoplethysmography. Carotid-femoral pulse wave velocity (cfPWV) and carotid stiffness were measured via tonometry and ultrasound. Blood velocity pulsatility index (PI) was measured at the middle cerebral (MCA) and common carotid artery (CCA) using Doppler, with pulsatile damping calculated as CCA PI divided by MCA PI. Increases in cfPWV were driven by changes in mean pressure during CP but not during LBNP in both groups (P<0.05). Pulsatile damping decreased in both groups (P<0.05) despite reductions in MCA PI and greater carotid dilatation during CP in young compared with middle-aged adults (P<0.05). Pressure-independent increases in cfPWV during LBNP did not alter pulsatile damping but decreased MCA PI in both young and middle-aged adults (P<0.05). These data suggest that changes in carotid diameter and cerebrovascular pulsatility differ between young and middle-aged adults despite similar changes in cerebral pulsatile damping during blood pressure-dependent, but not blood pressure-independent, increases in large artery stiffness.

Common carotid flow velocity is associated with cognitive function after carotid endarterectomy

The relationship between ultrasonographic flow parameters and cognitive function has not been well studied. This study aimed to clarify associations between carotid flow velocity (FV) and cognitive function in patients with a history of carotid endarterectomy (CEA). Ninety-four patients who previously underwent CEA participated in this study. The Neurobehavioral Cognitive Status Examination (Cognistat) and Frontal Assessment Battery (FAB) were adopted to assess cognitive functions at a mean of 6.5 ± 3.2 years after CEA. End-diastolic flow velocity (EDV) of the left and right common carotid artery (CCA) was significantly associated with total Cognistat score (p < 0.001) and total FAB score (p < 0.05). Pulsatility index (PI) of the left CCA was significantly associated with total Cognistat score and total FAB score (p < 0.01). A cut-off right CCA EDV of 14.5 cm/s offered the most reliable predictor of the bottom 25th percentile of total Cognistat score (sensitivity 83.3%, specificity 61.0%, area under the curve (AUC) 0.731, p = 0.0060), while a cut-off left CCA PI of 1.83 was the most reliable predictor of the bottom 25th percentile of total FAB score (sensitivity 73.3%, specificity 60.0%, AUC 0.679, p = 0.0179). Left and right CCA EDV correlated with sub-components of comprehension, construction, judgment, programming (p < 0.01), and conceptualization (p < 0.05). Right CCA EDV correlated with similarity (p < 0.01), repetition, naming, and memory (p < 0.05). Left CCA PI correlated with attention, conceptualization (p < 0.01), repetition, construction, similarity, and mental flexibility (p < 0.05), while right CCA PI correlated with construction (p < 0.05). CCA FV may offer useful markers of cognitive functions in patients with a history of CEA.

Acute effect of high-intensity cycling exercise on carotid artery hemodynamic pulsatility.

Investigate the effects of acute high-intensity exercise on common carotid artery (CCA) dimensions, stiffness, and wave intensity. Fifty-five healthy men and women (22 ± 5 year; 24.5 ± 2.7 kg m(-2)) underwent 30 s of high-intensity cycling (HIC; Wingate anaerobic test). CCA diameter, stiffness [β-stiffness, Elastic Modulus (E p)], pulsatility index (PI), forward wave intensities [due to LV contraction (W 1) and LV suction (W 2)], and reflected wave intensity [negative area (NA)] were assessed using a combination of Doppler ultrasound, wave intensity analysis, and applanation tonometry at baseline and immediately post-HIC. CCA β-stiffness, E p, PI and pulse pressure increased significantly immediately post-HIC (p < 0.05). CCA diameter decreased acutely post-HIC (p < 0.05). There were also significant increases in W 1 and NA and a significant decrease in W 2 (p < 0.05). A significant correlation was found between change in W 1 and PI (r = 0.438, p < 0.05), from rest to recovery as well as a significant inverse correlation between W 2 and PI (r = -0.378, p < 0.05). Change in PI was not associated with change in CCA stiffness or NA (p > 0.05). Acute HIC results in CCA constriction and increases in CCA stiffness along with increases in hemodynamic pulsatility. The increase in pulsatility may be due to a combination of increased forward wave intensity from increased LV contractility into a smaller vessel (i.e. impaired matching of diameter and flow) coupled with reduced LV suction.

Cognition may be related to arterial pulsatility index in HD patients.

Hemodialysis (HD) patients have a heavy burden of subclinical cerebrovascular disease and cognitive changes consistent with a vascular etiology. Pulsatility index is associated with microangiopathy of cerebral blood vessels and an increased risk of cerebral infarction. The proposed study was to determine common carotid artery pulsatility index (CCAPI) and its relation to cognition in well-dialyzed HD patients with no history of stroke or dementia and matched controls. Observational, cross-sectional study of CCAPI and cognition in 37 hemodialysis outpatients and 18 matched controls with normal kidney function. Non-parametric analyses were used to compare variables between groups. Multiple regression and ANOVA models were used to adjust for risk factor differences. Controls had a lower CCAPI than the HD group (1.7 ± 0.3 vs. 2.1 ± 0.4 cm/s, p = 0.006). HD patients scored significantly lower on all cognitive domains. Attention correlated with CCAPI in HD patients, independent of hypertension, diabetes, hyperlipidemia, and years on HD (r2 = -0.36, p = 0.01). CCAPI correlated with years on HD, independent of traditional cardiovascular risk factors. (r2 = 0.26, p = 0.04). In well-dialyzed hemodialysis patients with no history of stroke or dementia, CCAPI may correlate with cognitive function and represent a marker for underlying cerebral microvascular disease.

Effect of acute resistance exercise on carotid artery stiffness and cerebral blood flow pulsatility

Arterial stiffness is associated with cerebral flow pulsatility. Arterial stiffness increases following acute resistance exercise (RE). Whether this acute RE-induced vascular stiffening affects cerebral pulsatility remains unknown. Purpose: To investigate the effects of acute RE on common carotid artery (CCA) stiffness and cerebral blood flow velocity (CBFv) pulsatility. Methods: Eighteen healthy men (22 ± 1 yr; 23.7 ± 0.5 kg·m−2) underwent acute RE (5 sets, 5-RM bench press, 5 sets 10-RM bicep curls with 90 s rest intervals) or a time control condition (seated rest) in a randomized order. CCA stiffness (β-stiffness, Elastic Modulus (Ep)) and hemodynamics (pulsatility index, forward wave intensity, and reflected wave intensity) were assessed using a combination of Doppler ultrasound, wave intensity analysis and applanation tonometry at baseline and 3 times post-RE. CBFv pulsatility index was measured with transcranial Doppler at the middle cerebral artery (MCA). Results: CCA β-stiffness, Ep and CCA pulse pressure significantly increased post-RE and remained elevated throughout post-testing (p < 0.05). No changes in MCA or CCA pulsatility index were observed (p > 0.05). There were significant increases in forward wave intensity post-RE (p < 0.05) but not reflected wave intensity (p > 0.05). Conclusion: Although acute RE increases CCA stiffness and pressure pulsatility, it does not affect CCA or MCA flow pulsatility. Increases in pressure pulsatility may be due to increased forward wave intensity and not pressure from wave reflections.

Effects of Upper Meridian Massage on Cerebral Blood flow, Emotions, and Sleep of the Institutionalized Elderly

Purpose: This study was to investigate the effects of upper meridian massage on cerebral blood flow, emotions, and sleep of the institutionalized elderly. Methods: This study was a nonequivalent control group pre- and post-test design. The participants were 50 elderly (26 in the experimental group; 24 in the control group) living in the institutions. Data were collected between July 9 and September 1, 2011. The data were analyzed using descriptive statistics, t-test, and x 2 -test, Repeated Measures ANOVA, and Cronbach’s ⍺ coefficient. Each participant in the experimental group received the upper meridian massage for 10 minutes, 4 times per week for 2 weeks. Each participant’s cerebral blood flow and self-reported questionnaires were tested before treatment, after 1 week and 2 weeks during treatment sessions. Results: There were significant differences in sleep and emotions after 1 week and 2 weeks during treatment sessions. But cerebral blood flow measured by common carotid artery pulsatility index (CCA PI) and common carotid artery resistance index (CCA RI) demonstrated significant differences in 2 week point in time. Conclusion: These results indicated that upper meridian massage could be an effective intervention for improving cerebral blood flow, emotions, and sleep of the institutionalized elderly.

Are increased carotid artery pulsatility and resistance indexes early signs of vascular abnormalities in young obese males?

To provide insight into the factors by which obesity in itself may directly lead to early arterial damage, we aimed to determine early sonographic markers of obesity-related vascular dysfunction in young obese males. Thirty-five young obese males and 23 age-matched healthy male volunteers were recruited into the study. Common carotid artery pulsatility index and resistance index were calculated from blood flow velocities curves obtained by pulsed Doppler ultrasonography. The mean pulsatility index, resistance index, body mass index, waist circumference, systolic and diastolic blood pressure, homeostasis model assessment for insulin resistance, plasma fasting glucose, insulin, C-peptide, triglycerides, low-density lipoprotein cholesterol, and high-sensitivity C-reactive protein were statistically higher in obese subjects than in healthy controls. Our results suggest that depressed vessel compliance and increased vascular resistance are features of young, obese, normotensive subjects independently of and in addition to cardiovascular risk factors. As changes in arterial wall properties may be incipient in young obese subjects, future studies will be required to demonstrate whether early intervention such as diet and exercise in this population can improve vascular functions.

Conjugated estrogen administration improves common carotid artery elastic properties in normotensive postmenopausal women.

Various vascular effects of estrogens have been proposed to explain further the beneficial effect of replacement therapy in cardiovascular events. The study was undertaken to assess the effect of conjugated estrogen on the elastic properties of the large arteries in normotensive, healthy, postmenopausal women. Toward this end, we investigated the acute effect of conjugated estrogen on the elastic properties of the common carotid artery (CCA) in 20 normotensive, healthy, postmenopausal women (age 54+/-3 years) at baseline and 20 min after the intravenous administration of 1.25 mg conjugated estrogens. The CCA distensibility was derived by a combination of surface ultrasonographic data and simultaneous blood pressure measurements at the brachial artery. The carotid pulsatility index, a measure of brain impedance, was determined electronically by tracing the CCA Doppler waveform. At baseline, CCA distensibility had a negative correlation with both patients' age and time since menopause (r = -0.57 and r = -0.48, p < 0.05 for both cases). After estrogen administration, estradiol and estrone plasma levels were restored to the range of usual premenopausal values. Estrogen induced a significant increase in CCA distensibility by 0.92+/-0.005 dyne(-1) x cm2 x 10(-6) (from 2.03 to 2.95 dyne(-1) x cm2 x 10(-6)) and a significant reduction in CCA pulsatility index by 0.24+/-0.06, (from 2.17 to 1.93) (p < 0.001 for both cases). The improvement in CCA distensibility had a negative correlation with both patients' age and time since menopause (r= -0.46 and r = -0.44, respectively, p < 0.05 for both cases). Acute conjugated estrogen administration induced an improvement in CCA elasticity and a reduction in brain impedance in normotensive, postmenopausal women. As the age of women and the time since menopause increased, the improvement in carotid distensibility decreased in such selected subjects.

Doppler study of the fetal circulation during long-term maternal hyperoxygenation for severe early onset intrauterine growth retardation.

In 21 severely growth-retarded, hypoxemic fetuses at 22-30 weeks' gestation, the effect of long-term maternal hyperoxygenation on serial Doppler measurements of the fetal descending thoracic aorta mean velocity (Vm), common carotid artery pulsatility index (PI) and umbilical artery PI was investigated. The treatment was continued on average for 4 weeks and delivery, at 26-34 weeks, was decided for fetal or maternal indications. In the subgroup of 12 fetuses that survived, the mean aortic V(m) increased within 72 h of maternal hyperoxygenation. This increase continued for 1-8 weeks, after which there was a decrease to pretreatment values. In the subgroup of neonatal deaths (n = 5)) there was a non-significant increase in mean aortic V(m). In the subgroup of intrauterine deaths (n = 4), there was a non-significant trend for continuing deterioration in mean aortic V(m) throughout the period of maternal hyperoxygenation. The mean carotid PI did not change significantly in any of the subgroups during maternal hyperoxygenation. However, in the subgroup that survived there was a tendency for improvement and in the subgroup of intrauterine deaths a tendency for deterioration. The mean umbilical artery PI did not change significantly in any of the groups or subgroups during maternal hyperoxygenation. Therefore, measurement of aortic V(m) is a useful indicator of fetal response to maternal hyperoxygenation and its increase constitutes a favorable prognostic factor.

Doppler measurements of fetal and uteroplacental circulations: Relationship with umbilical venous blood gases measured at cordocentesis

A pulsed Doppler study of the fetal and uteroplacental circulations was performed on 41 pregnant women with small-for-gestational-age and 10 women with appropriate-for-gestational-age fetuses at 19 to 37 weeks' gestation. Blood gases and pH, measured in umbilical venous samples obtained by cordocentesis within 1 hour of the Doppler studies, were correlated individually and as an "asphyxia" index, to the Doppler and ultrasonographic biometric measurements. Although there were significant correlations between the majority of the ultrasonographic biometric and Doppler measurements with the blood gas results, better correlations were found with the ratio of common carotid artery to descending thoracic aorta mean velocity and pulsatility index. The best predictor of asphyxia was an index comprising aortic mean velocity and the common carotid artery pulsatility index. When this index was abnormal, 89% of fetuses had an asphyxia index 1 SD above the mean and 60% 2 SDs above the mean. A normal index was always associated with normal blood gases. The indices representing the inverse relationship of impedance and velocity in the two major vessels that supply the brain and the abdominal viscera provide the best prediction of the fetal condition because they reflect the hemodynamic response to changes in the partial pressure of respiratory gases.