Carotid ultrasound pulsatility indices and cardiovascular risk in Australian women

Correlation between Carotid Blood Flow Velocity and Total Magnetic Resonance Imaging Burden of Cerebral Small Vessel Disease in Patients with Recent Small Subcortical Infarcts

BACKGROUND

The common and internal carotid arteries are the upstream vessels of the small cerebral vessels. The relationship between hemodynamic changes in the significant cervical vessels and cerebral small vessel disease (CSVD) remains uncertain. This research sought to analyze the correlation between carotid blood flow velocity and the total magnetic resonance imaging (MRI) burden of CSVD in patients with recent small subcortical infarcts (RSSIs).

METHODS

Data were gathered from individuals diagnosed with RSSIs admitted to Changzhou Second People's Hospital between January 2022 and June 2023. Brain MRI was performed on every patient to determine the overall MRI burden of CSVD, along with carotid duplex ultrasound to evaluate carotid blood flow velocity and pulsatility index (PI) of the common carotid (CCA) and internal carotid (ICA) arteries. The association between carotid blood flow velocity and the total MRI load of CSVD was examined using univariate and multivariate analyses.

RESULTS

For our investigation, 272 individuals with RSSIs were screened. 82 individuals had a moderate to severe load of CSVD, while 190 participants showed a mild burden. Patients with moderate to severe burden of CSVD had lower end-diastolic velocity (EDV) and higher PI in CCA and ICA than those with mild load (P < 0.001). After adjusting for variables like age, hypertension, systolic blood pressure, and blood homocysteine levels, multivariate logistic regression analysis showed that EDV in CCA (OR, 0.894; P = 0.011), PI in CCA (OR, 5.869; P = 0.017), EDV in ICA (OR, 0.909; P = 0.008), and PI in ICA (OR, 5.324; P = 0.041) were independently related to moderate to severe CSVD burden. Spearman correlation analysis showed that EDV in CCA and ICA was negatively related to the total MRI load of CSVD in patients with RSSIs (P < 0.001). PI in CCA and ICA was positively associated with the whole MRI load of CSVD (P < 0.001).

CONCLUSION

Low carotid blood flow velocity and high carotid pulsatility index are independently associated with moderate to severe burden of CSVD.

Effectiveness of pulsatility index of carotid Doppler ultrasonography to predict cardiovascular events

PURPOSE

The pulsatility index (PI) obtained from carotid ultrasonography is considered to be a marker of cerebrovascular resistance. However, the impact of PI on cardiovascular events has yet to be fully addressed.

METHOD

Fifty-four patients who underwent both carotid ultrasonography and coronary angiography were followed for 5.9 ± 3.2 years. The relationship between the incidence of cardiovascular events and PI was investigated.

RESULT

There were 10 (19%) deaths, four (7%) cardiovascular deaths, and nine (17%) major adverse cardiovascular events (MACEs). The cardiovascular events-defined as all hospitalization for MACEs plus heart failure, revascularization, and cardiovascular surgery-occurred in 21 patients (39%). The patients were divided into two groups according to each threshold of PI value for common carotid arteries (CCA), internal carotid arteries (ICA), and external carotid arteries (ECA), respectively. The thresholds were calculated based on receiver-operating characteristic curves for cardiovascular events. Log-rank test showed that the groups with CCA-PI ≥ 1.71, ICA-PI ≥ 1.20, and ECA-PI ≥ 2.46 had a higher incidence of cardiovascular events, respectively (p < 0.05). ECA-PI ≥ 2.46 was associated with an increased incidence of MACEs. Multivariate Cox regression analysis adjusting for cardiovascular risk factors showed that high PI of CCA, ICA, or ECA was a risk factor for cardiovascular events, respectively (CCA-PI ≥ 1.71, hazard ratio (HR) 3.242, p = 0.042; ICA-PI ≥ 1.20, HR 3.639, p = 0.012; ECA-PI ≥ 2.46, HR 11.322, p = 0.001).

CONCLUSION

The results suggested that carotid PIs were independent predictive factors for further cardiovascular events. In particular, high ECA-PI levels may reflect severe arteriosclerosis.

Arterial Function after a 246 km Ultra-marathon Running Race

There is little research about the effects of ultra-endurance exercise on arterial morphological and functional properties. The aim was to assess the acute changes of the carotid-femoral pulse wave velocity and carotid doppler-derived parameters following an ultra-marathon race as well as the intima-media thickness of the carotid artery in ultra-marathon runners. Twenty athletes were examined at baseline and within 10 mins after a 246 km running race. Measurements included carotid-femoral pulse wave velocity, peak-systolic and end-diastolic velocities of carotid artery blood flow, pulsatility and resistivity indices and blood biochemical parameters. The intima-media thickness of the right and left carotid artery was measured before the race. Arterial stiffness and carotid artery intima media thickness at rest remained within known normal limits. The ultra-marathon race significantly increased carotid-femoral pulse wave velocity by 22.6% and pulsatility index by 10.2%. There was a decrease in body weight by 3.35% and an increase of all biochemical markers of muscle damage after the race. Additionally, C-reactive protein was correlated with both pulsatility and resistivity indices post-race. This study shows that immediately after a 246 km ultra-marathon running race, acute increase of arterial stiffness and vascular resistance were evident. The carotid artery thickness of ultra-marathon runners was within normal range.

Assessment of carotid stiffness by measuring carotid pulse wave velocity using a single-slice oblique-sagittal phase-contrast MRI

PURPOSE

Increased arterial stiffness has been shown to be one of the earliest markers of cerebrovascular dysfunction. As a surrogate marker of arterial stiffness, pulse wave velocity (PWV) quantifications are generally carried out on central and peripheral arteries. The purpose of this study was to develop and evaluate an MRI approach to assess carotid stiffness by measuring carotid PWV (cPWV) using a fast oblique-sagittal phase-contrast MRI sequence.

METHODS

In 29 volunteers, a single-slice oblique-sagittal phase-contrast MRI sequence with retrospective cardiac gating was used to quantify blood velocity waveforms along a vessel segment covering the common carotid artery (CCA) and the internal carotid artery (ICA). The CCA-ICA segment length was measured from a region of interest selected on the magnitude image. Phase-contrast MRI-measured velocities were also used to quantify the ICA pulsatility index along with cPWV quantification.

RESULTS

The mean value of cPWV calculated using the middle upslope area algorithm was 2.86 ± 0.71 and 3.97 ± 1.14 m/s in young and elderly subjects, respectively. Oblique-sagittal phase-contrast MRI-derived cPWV measurements showed excellent intrascan and interscan repeatability. cPWV and ICA pulsatility index were significantly greater in older subjects compared to those in the young subjects (P < .01 and P = .01, respectively). Also, increased cPWV values were associated with elevated systolic blood pressure (β = 0.05, P = .03).

CONCLUSION

This study demonstrated that oblique-sagittal phase-contrast MRI is a feasible technique for the quantification of both cPWV and ICA pulsatility index and showed their potential utility in evaluating cerebroarterial aging and age-related neurovascular disorders.

Effect of Intensive Blood Pressure Control on Carotid Morphology and Hemodynamics in Chinese Patients with Hyperhomocysteinemia-Type Hypertension and High Risk of Stroke

BACKGROUND Different blood pressure targets should be formulated for different groups of people. This study aimed to assess the effectiveness of intensive blood control in improving the carotid morphology and hemodynamics in Chinese patients with hyperhomocysteinemia-type hypertension and high risk of stroke. MATERIAL AND METHODS Chinese hypertensive patients with high risk of stroke were randomized to intensive (n=187) and standard (n=192; controls) blood pressure management groups. Systolic blood pressure (SBP) targets were 100< SBP ≤120 and 120< SBP ≤140 mmHg, respectively. All patients received folic acid 0.8 mg/d and atorvastatin 20 mg/d. Calcium antagonist was first used. If blood pressure was still uncontrolled, angiotensin-converting enzyme inhibitor or angiotensin receptor antagonist, ß-receptor blocker, and diuretics were added successively. Follow-up was 12 months. Carotid features, hemodynamics, and adverse events were examined. RESULTS There were no differences in sex, age, body mass index, blood lipids, baseline carotid parameters, and histories of smoking, diabetes, statin use, and stroke between the 2 groups. Carotid plaques after 12 months of treatment were 19.4±2.1 and 23.6±3.1 cm² for the intensive and control groups, respectively (P=0.038). Plaque scores were lower in the intensive group (1.75±0.52 vs. 2.45±0.47, P=0.023). Compared with controls, intensive management resulted in relatively higher Vd and significantly lower Vs/Vd, PI, and RI (all P<0.05). Major adverse events such as hypotension (n=5 (2.7%) vs. 3 (1.6%), P=0.020) and dizziness (n=20 (10.7%) vs. 16 (8.3%), P=0.041) were more frequent in the intensive group. CONCLUSIONS Intensive blood pressure management could be beneficial for Chinese patients with hyperhomocysteinemia-type hypertension and high risk of stroke.

Carotid Flow Augmentation, Arterial Aging, and Cerebral White Matter Hyperintensities

Objective—

Aortic stiffness and pressure wave reflection are associated with age-related cerebral microvascular disease, but the underlying mechanism remains obscure. We hypothesized that cerebral (carotid) flow alterations potentially mediate these associations.

Approach and Results—

Doppler waveforms were recorded in 286 patients with hypertension to measure the carotid flow augmentation index (FAIx) as the late/early-systolic velocity amplitude ratio. Tonometric waveforms were recorded to estimate the aortic pressure AIx (PAIx), aortic compliance, and carotid-femoral and carotid-radial pulse wave velocities. Additionally, white matter hyperintensities on brain magnetic resonance imaging were evaluated using the Fazekas scale. With increasing age, the carotid late systolic velocity increased, whereas the early systolic velocity decreased, although the aortic augmented pressure increased in parallel with the incident wave height ( P <0.001). Both FAIx and PAIx increased with age, but the age-dependent curves were upwardly concave and convex, respectively. FAIx increased exponentially with increasing PAIx ( r =0.71). Compared with PAIx, FAIx was more closely ( P ≤0.001) correlated with the aortic pulse wave velocity, aortic compliance, and elastic/muscular pulse wave velocity ratio. FAIx was associated with white matter hyperintensities scores independently of confounders including age, sex, diabetes mellitus, hypercholesterolemia, and aortic pulse wave velocity ( P =0.01), and was more predictive of white matter hyperintensities presence than PAIx.

Conclusions—

Carotid FAIx had closer associations with age, aortic stiffness, and cerebral white matter hyperintensities than aortic PAIx. These results indicate that carotid flow augmentation (enhanced by aortic stiffening and pressure wave reflection from the lower body) causes microcerebrovascular injury potentially through increasing cerebral flow pulsations, but this detrimental effect is greater than that estimated from PAIx.

Age and sex-specific associations of carotid pulsatility with small vessel disease burden in transient ischemic attack and ischemic stroke

Background Although large artery stiffness has been implicated in the pathogenesis of cerebral small vessel disease, whether carotid pulsatility, a convenient surrogate marker of arterial stiffness, is similarly associated with global burden of small vessel disease is unknown. Aims To determine the age and sex-specific associations of carotid pulsatility with global burden of small vessel disease. Methods We studied consecutive patients with transient ischemic attack or non-disabling ischemic stroke from the Oxford Vascular Study who had a brain MRI and carotid duplex ultrasound during 2002-2014. We determined clinical correlates of common carotid artery (CCA) and internal carotid artery (ICA) pulsatility index (PI) and their associations with the total small vessel disease score on MRI, stratified by age (median = 72). Results In 587 patients, correlates of CCA and ICA-PI were both independently associated with age, diabetes, and premorbid mean pulse pressure after adjustment for age, sex, and cardiovascular risk factors (all p < 0.05). ICA-PI was strongly associated with small vessel disease markers and burden, particularly lacunes, in patients aged<70 (age and sex-adjusted odds ratio of top vs. bottom pulsatility index quartile: 5.35, 1.95-14.70, p = 0.001; increasing small vessel disease score: 2.30, 1.01-5.25, p = 0.048), but not in patients aged ≥ 70 ( p > 0.05). No associations between CCA-PI with small vessel disease score were noted at any age. In 94 consecutive patients who also received transcranial Doppler ultrasound, strong associations between middle cerebral artery (MCA)-PI and an increasing small vessel disease score were noted (unadjusted OR-MCA: 4.26, 1.45-12.55, p = 0.009; ICA: 2.37, 0.81-6.87, p = 0.11; CCA: 1.33, 0.45-3.96, p=0.61). Conclusions ICA and MCA-PI are associated with global small vessel disease burden, especially in individuals aged<70 and may be causally related.

White matter hyperintensities in migraine: Clinical significance and central pulsatile hemodynamic correlates

Background The role of central pulsatile hemodynamics in the pathogenesis of white matter hyperintensities in migraine patients has not been clarified. Methods Sixty patients with migraine (20-50 years old; women, 68%) without overt vascular risk factors and 30 demographically-matched healthy controls were recruited prospectively. Cerebral white matter hyperintensities volume was determined by T1-weighted magnetic resonance imaging with CUBE-fluid-attenuated-inversion-recovery sequences. Central systolic blood pressure, carotid-femoral pulse wave velocity, and carotid augmentation index were measured by applanation tonometry. Carotid pulsatility index was derived from Doppler ultrasound carotid artery flow analysis. Results Compared to the controls, the migraine patients had higher white matter hyperintensities frequency (odds ratio, 2.75; p = 0.04) and greater mean white matter hyperintensities volume (0.174 vs. 0.049, cm³, p = 0.04). Multivariable regression analysis showed that white matter hyperintensities volume in migraine patients was positively associated with central systolic blood pressure ( p = 0.04) and carotid-femoral pulse wave velocity ( p < 0.001), but negatively associated with carotid pulsatility index ( p = 0.04) after controlling for potential confounding factors. The interaction effects observed indicated that the influence of carotid-femoral pulse wave velocity ( p = 0.004) and central systolic blood pressure ( p = 0.03) on white matter hyperintensities formation was greater for the lower-carotid pulsatility index subgroup of migraine patients. White matter hyperintensities volume in migraine patients increased with decreasing carotid pulsatility index and with increasing central systolic blood pressure or carotid-femoral pulse wave velocity. Conclusions White matter hyperintensities are more common in patients with migraine than in healthy controls. Increased aortic stiffness or central systolic blood pressure in the presence of low intracranial artery resistance may predispose patients with migraine to white matter hyperintensities formation.

Blood Pressure, Carotid Flow Pulsatility, and the Risk of Stroke: A Community-Based Study

BACKGROUND AND PURPOSE

High blood pressure is a major cause of cardiovascular events, and carotid flow pulsatility may be associated with cardiovascular events. However, the combined effect of blood pressure and flow pulsatility on the development of stroke remains unclear. Therefore, we investigated the combined influence of central blood pressure and pulsatility index (PI) on the incidence of stroke.

METHODS

Baseline data from 2033 adults (≥30 years) without stroke history in the Cardiovascular Disease Risk Factor Two-Township Study were linked to incident stroke. Common carotid flow PI was calculated by peak systolic velocity, end-diastolic velocity, and mean vessel velocity, which were measured in the common carotid artery. Hazard ratios for the risk of total stroke resulting from high central systolic blood pressure (CSBP) and high PI were calculated with Cox proportional hazard models.

RESULTS

Over a median follow-up of 9.81 years, 132 people incurred stroke events. The incidence rates of stroke were 1.3, 6.4, and 13.2 per 1000 person-years for tertile groups of CSBP (P for trend<0.05) and 4.3, 7.0, and 9.4 per 1000 person-years for tertile groups of PI (P for trend<0.05). Compared with the first tertile of CSBP, hazard ratios were 4.88 (95% confidence interval, 2.29-10.43) for the second tertile and 10.42 (5.05-21.53) for the third tertile. Hazard ratios of PI were 2.18 (1.39-3.42; third tertile) and 1.64 (1.02-2.63; second tertile) compared with the first tertile. The individuals with a high CSBP and high PI had a 13-fold higher stroke risk compared with those with low CSBP and low PI (13.2; 1.75-99.71) after adjusting for age, sex, and traditional cardiovascular risk.

CONCLUSIONS

CSBP and common carotid PI jointly and independently predicted future stroke. Carotid flow pulsatility may play an important role in the development of stroke.