Carotid intima-media thickness (C-IMT) measured noninvasively by ultrasonography is widely used as a marker for increased risk of cardiovascular disease. Also hyperuricemia (HU) is a well recognized risk factor for cardiovascular diseases. The study was designed to assess the relation between hyperuricemia and carotid intima-media thickness C-IMT in patients with and without hypertension (HTN).
This study included 126 patients divided into four groups: (1) Group A, included 59 hypertensive patients with hyperuricemia. (2) Group B, included 29 hypertensive patients without hyperuricemia. (3) Group C, included 17 patients with hyperuricemia and normal blood pressure without history of hypertension. (4) Group D, included 21 control subjects.
We measured carotid intima-media thickness by B-mode ultrasound in the common carotid and internal carotid artery. Routine echocardiography and uric acid level was assessed for all patients.
We found that C-IMT was significantly higher in group A, B and C than group D; and it was significantly higher in group A than B. This means that C-IMT is significantly higher in all hypertensive groups than control group but it was significantly higher in hypertensive hyperuricemia (group A) than those hypertensives without hyperuricemia. We also observed a higher C-IMT in hyperuricemic non hypertensive patients than control group this means that hyperuricemia per se could be a risk factor for atherosclerosis.
Uric acid levels among the whole number of patients included in the study and among the groups with hyperuricemia (group A and C) were positively correlated with the intimal-media thickness (IMT) while there were no correlations in the other two groups without hyperuricemia.
We found that left ventricular hypertrophy (LVH) was significantly higher in hypertensive patients (group A&B) than normotensives (group C&D) either with or without hyperuricemia and this was evident in the hypertensive hyperuricemic patients (group A); but unexpectedly we observed the presence of LVH in the hyperuricemic non hypertensive patients (group C) which was significantly higher than the control group (group D). This means that hyperuricemia is a risk factor for development of LVH hypertrophy independently of hypertension.
Therefore, higher serum uric acid levels are associated with increased C-IMT and left ventricular hypertrophy in hypertensive and even non hypertensive patients. So, early screening for hyperuricemia and lowering serum uric acid levels might be beneficial in slowing progression of atherogenesis.
Hyperuricemia; Hypertension; Left ventricular hypertrophy; Caroid intima mediathickness
Background: The Carotid Intima-Media Thickness (CIMT) is a simple and an inexpensive tool which can be used to assess the cumulative effect of atherosclerotic risk factors and it is also an independent predictor of the future cardiovascular risk. Nevertheless, criticism has been raised throughout the scientific community, based on the observations which indicated a weak correlation between CIMT and coronary atherosclerosis.
It has been suggested by the International Atherosclerosis Project, that the atherosclerotic process occurs at the same time in the carotid, cerebral and the coronary arteries. Measurement of the Carotid Intima-Media Thickness (CIMT) of the Common Carotid Artery (CCA) by B-mode ultrasound was found to be a suitable non-invasive method, to visualize the arterial walls and to monitor the early stages of the atherosclerotic process.
Aim: This study sought to determine the usefulness of B-mode ultrasound as a non-invasive marker to examine the association between CIMT and the extent and the severity of coronary artery disease and its association with the cardiovascular risk factors, if any.
Methods: A cross-sectional study was done among hundred cases and hundred age and sex matched controls who were in the age group of 30-65 years. The cases included those who had undergone coronary angiography. The controls included non-diabetic non-hypertensives with no cardiovascular risk factors. The CIMT was assessed by using a 7MHz linear array transducer. Fasting blood samples were collected for measuring the blood sugar and the lipid profiles.
Results: The statistical analysis was done by using the Student’s t test and ANOVA and a p value of <0.001 was considered to be significant. The Average Carotid Intima Media Thickness (AVCIMT) was higher in the cases (0.90 vs 0.47 in controls, p<0.001, very highly significant). The AVCIMT was found to be higher in those with triple vessel disease (1.00mm)
Conclusion: The easy applicability and the non invasive nature of B-mode ultrasonography make it suitable for use as a surrogate endpoint for measuring the atherosclerotic burden in people with cardiovascular risk factors. Even in this present study, we found a significant association between the extent of carotid atherosclerosis which was measured by B-mode ultrasound, and the presence, its extent, or the lack of coronary atherosclerosis which was documented by coronary angiography.
Atherosclerosis; Carotid; Intima; Coronary
Cardiovascular disease (CVD), associated with vascular atherosclerosis, is the major cause of death in Western societies. Current risk estimation tools, such as Framingham Risk Score (FRS), based on evaluation of multiple standard risk factors, are limited in assessment of individual risk. The majority (about 70%) of the general population is classified as low FRS where the individual risk for CVD is often underestimated but, on the other hand, cholesterol lowering with statin is often excessively administered. Adverse effects of statin therapy, such as muscle pain, affect a large proportion of the treated patients and have a significant influence on their quality of life.
Coronary artery calcification (CAC), as assessed by computed tomography, carotid artery intima-media thickness (CIMT), and especially presence of plaques as assessed by B-mode ultrasound are directly correlated with increased risk for cardiovascular events and provide accurate and relevant information for individual risk assessment. Absence of vascular pathology as assessed by these imaging methods has a very high negative predictive value and therefore could be used as a method to reduce significantly the number of subjects who, in our opinion, would not benefit from statins and only suffer from their side-effects.
In summary, we suggest that in very-low-risk subjects, with the exception of subjects with low FRS with a family history of coronary artery disease (CAD) at young age, if vascular imaging shows no CAC or normal CIMT without plaques, statin treatment need not be administered.
Framingham Risk Score; cardiovascular disease; coronary artery calcification; carotid artery intima-media thickness; statin; atherosclerosis
To study the utility of risk scores in prediction of subclinical atherosclerosis in young adults.
Methods and results
Participants were 2,204 healthy Finnish adults aged 24–39 years in 2001 from population-based follow-up study Cardiovascular Risk in Young Finns. We examined the performance of the Framingham, Reynolds, SCORE (Systematic Coronary Risk Evaluation), PROCAM, and Finrisk cardiovascular risk scores to predict subclinical atherosclerosis, i.e. carotid artery intima-media thickness(IMT) and plaque, carotid artery distensibility (CDist) and brachial artery flow-mediated dilatation (FMD) 6 years later. In 6-year prediction of high IMT (highest decile or plaque), areas under the receiver operating characteristic curves (AUC) for baseline Finrisk (0.733), SCORE (0.726), PROCAM (0.712) and Reynolds (0.729) risk scores were similar as for Framingham risk score (0.728, P always ≥0.15). All risk scores had similar discrimination in predicting low CDist (lowest decile) (0.652, 0.642, 0.639, 0.658, 0.652 respectively, P always ≥0.41). In prediction of low FMD (lowest decile), Finrisk, PROCAM, Reynolds and Framingham scores had similar AUCs (0.578, 0.594, 0.582, 0.568, P always ≥0.08) and SCORE discriminated slightly better (AUC=0.596, P<0.05). Prediction of subclinical outcomes was consistent when estimated from other statistical measures of discrimination, reclassification, and calibration.
CVD risk scores had equal performance in predicting subclinical atherosclerosis measured by IMT and CDist in young adults. SCORE was more accurate at predicting low FMD than Framingham risk score.
cardiovascular risk score; subclinical atherosclerosis; ultrasound
Secondary treatment of arteriosclerosis may be applicable for the primary prevention of atherosclerosis in diabetic patients. This prospective, 2-year follow-up study was designed to determine the efficacy and safety of antiplatelet therapy in the prevention of atherosclerosis of diabetic subjects.
Patients with type 2 diabetes and arteriosclerosis obliterans from the Eastern Asian countries were registered online and randomly assigned either to the aspirin group (81–100 mg/day) or the cilostazol group (100–200 mg/day) in this international, 2-year, prospective follow-up interventional study.
The primary study endpoint was changes in right and left maximum intima-media thickness of the common carotid artery. Secondary endpoints include changes in right and left maximum intima-media thickness of the internal carotid artery; semiquantitative evaluation of cerebral infarction by magnetic resonance imaging; cardiovascular events including sudden death, stroke, transient cerebral ischemic attacks, acute myocardial infarction, angina, and progression of arteriosclerosis obliterans; overall death; withdrawal; and change in ankle-brachial pressure index.
This is the first study to use an online system that was developed in Asian countries for pooling data from an international clinical trial. These findings are expected to help in the prevention of diabetic atherosclerosis and subsequent cardiovascular and cerebrovascular disease.
Background and Purpose
We propose to study possible differences in the associations between risk factors for cardiovascular disease (myocardial infarction and stroke) and Carotid Intima-Media thickness (IMT) measurements made at three different levels of the carotid bifurcation. Methods: Cross-sectional study of a cohort of Whites and African Americans of both genders with mean age 45 years. Traditional cardiovascular risk factors were determined in cohort members. Carotid IMT was measured from high-resolution B-mode ultrasound images at three levels: the common carotid artery (CCA), the carotid artery bulb (Bulb) and the internal carotid artery (ICA). Associations with risk factors were evaluated by multivariate linear regression analyses.
Of 3258 who underwent carotid IMT measurements, CCA, Bulb, and ICA IMT were measured at all three separate levels in 3023 (92.7%). A large proportion of the variability of CCA IMT was explained by cardiovascular risk factors (26.8%) but less so for the Bulb (11.2%) and ICA (8.0%). Carotid IMT was consistently associated with age, LDL-cholesterol, smoking and hypertension in all segments. Associations with fasting glucose and diastolic blood pressure were stronger for CCA than for the other segments. Hypertension, diabetes and current smoking had qualitatively stronger associations with Bulb IMT, and LDL cholesterol with ICA IMT. Conclusion: In our cohort of relatively young white and African-American men and women, a greater proportion of the variability in common carotid IMT can be explained by traditional cardiovascular risk factors than for the carotid artery bulb and internal carotid arteries.
Carotid Intimal Medial Thickness; Risk Factors; Carotid Ultrasound
Carotid artery intima-media thickness (IMT) is a marker of cardiovascular disease associated with incident stroke. We study whether IMT rate-of-change is associated with stroke.
Materials and Methods
We studied 5028 participants of the Multi-Ethnic Study of Atherosclerosis (MESA) composed of whites, Chinese, Hispanic and African-Americans free of cardiovascular disease. In this MESA IMT progression study, IMT rate-of-change (mm/year) was the difference in right common carotid artery (CCA) far-wall IMT (mm) divided by the interval between two ultrasound examinations (median interval of 32 months). CCA IMT was measured in a region free of plaque. Cardiovascular risk factors and baseline IMT were determined when IMT rate-of-change was measured. Multivariable Cox proportional hazards models generated Hazard risk Ratios (HR) with cardiovascular risk factors, ethnicity and education level/income as predictors.
There were 42 first time strokes seen during a mean follow-up of 3.22 years (median 3.0 years). Average age was 64.2 years, with 48% males. In multivariable models, age (HR: 1.05 per year), systolic blood pressure (HR 1.02 per mmHg), lower HDL cholesterol levels (HR: 0.96 per mg/dL) and IMT rate-of-change (HR 1.23 per 0.05 mm/year; 95% C.L. 1.02, 1.48) were significantly associated with incident stroke. The upper quartile of IMT rate-of-change had an HR of 2.18 (95% C.L.: 1.07, 4.46) compared to the lower three quartiles combined.
Common carotid artery IMT progression is associated with incident stroke in this cohort free of prevalent cardiovascular disease and atrial fibrillation at baseline.
Ultrasonography; Risk Factors; Carotid Arteries; Carotid Intima Media Thickness; stroke
Common carotid artery (CCA) intima-media thickness (cIMT), a measure of atherosclerosis, varies between peak-systole (PS) and end-diastole (ED). This difference might affect cardiovascular risk assessment.
Materials and methods
IMT measurements of the right and left CCA were synchronized with an electrocardiogram: R-wave for ED and T-wave for PS. IMT was measured in 2930 members of the Framingham Offspring Study. Multivariable regression models were generated with ED-IMT, PS-IMT and change in IMT as dependent variables and Framingham risk factors as independent variables. ED-IMT estimates were compared to the upper quartile of IMT based on normative data obtained at PS.
The average age of our population was 57.9 years. Average difference in IMT during the cardiac cycle was 0.037 mm (95% CI: 0.035–0.038 mm). ED-IMT and PS-IMT had similar associations with Framingham risk factors (total R2= 0.292 versus 0.275) and were significantly associated with all risk factors. In a fully adjusted multivariable model, a thinner IMT at peak-systole was associated with pulse pressure (p < 0.0001), LDL-cholesterol (p = 0.0064), age (p = 0.046), and no other risk factors. Performing ED-IMT measurements while using upper quartile PS-IMT normative data lead to inappropriately increasing by 42.1% the number of individuals in the fourth IMT quartile (high cardiovascular risk category).
The difference in IMT between peak-systole and end-diastole is associated with pulse pressure, LDL-cholesterol, and age. In our study, mean IMT difference during the cardiac cycle lead to an overestimation by 42.1% of individuals at high risk for cardiovascular disease.
Ultrasonics; Risk Factors; Carotid Arteries; Blood Pressure; systole; diastole
Coronary artery calcium (CAC) and carotid intima-media thickness (IMT) are noninvasive measures of atherosclerosis that consensus panels have recommended as possible additions to risk factor assessment for predicting the probability of cardiovascular disease (CVD) occurrence.
To assess whether maximum carotid IMT or CAC (Agatston Score) is the better predictor of incident CVD.
Design, Setting, Patients
Prospective cohort study of 45–84 year-olds initially free of CVD (n = 6,698) in four ethnic groups, with standardized carotid IMT and CAC measures at baseline, in six field centers of the Multi-Ethnic Study of Atherosclerosis (MESA).
Main Outcome Measure(s)
Incident CVD events (coronary heart disease, stroke, and fatal CVD) over a maximum of 5.3 years of follow-up.
There were 222 CVD events during follow-up. CAC was associated more strongly than carotid IMT with risk of incident CVD. After adjustment for each other and traditional CVD risk factors, the hazard of CVD increased 2.1-fold (95% CI 1.8–2.5) for each standard deviation greater level of log-transformed CAC, versus 1.3-fold (95% CI 1.1–1.4) for each standard deviation greater maximum IMT. For coronary heart disease, the hazard ratios per standard deviation increment were 2.5-fold (95% CI 2.1–3.1) for CAC and 1.2-fold (95% CI 1.0–1.4) for IMT. An ROC analysis also suggested that CAC predicted incident CVD better than IMT did.
Although whether and how to clinically use bio-imaging tests of subclinical atherosclerosis remains a topic of debate, this study found that CAC predicts subsequent CVD events better than does carotid IMT.
Background and Purpose
Carotid atherosclerosis has been associated with increased risk of stroke, and poorer cognitive performance in older adults. The relation of carotid atherosclerosis to cognitive impairment and MRI indices of ischemia and aging in midlife is less clear.
We studied 1,975 Framingham Offspring Study participants free of stroke and dementia with available carotid ultrasound, brain MRI and neuropsychological testing. We related common and internal carotid artery intima-media thickness (ICA-IMT and CCA-IMT respectively) and internal carotid stenosis (CAS) to large white matter hyperintensity (>1-SD above age-specific mean; LWMH), total brain volume (TCBV), hippocampal volume, silent cerebral infarcts (SCI) and neuropsychological measures of verbal memory, executive function and non-verbal memory measures.
We observed that ICA-IMT, but not CCA-IMT, was associated with higher prevalence of SCI (OR 1.21, 95% CI 1.03–1.43, p<0.05), LWMH (OR 1.19, 95% CI 1.03–1.38, p<0.05), lower TCBV (−0.05 per SD, p<0.05) and poorer performance in verbal memory (−0.06 per SD; p<0.05) and non-verbal memory measures (−0.08 per SD; p<0.01), but not with hippocampal volume. CAS ≥25% was associated with a higher prevalence of LWMH (adjusted OR 1.77, 95% CI 1.25–2.53) and lower TCBV (−0.11 per SD, p=0.042) but not with SCI or hippocampal volume. CAS ≥50% was associated with higher prevalence of SCI (OR 2.53, 95% CI 1.17 – 5.44), LWMH (OR 2.35, 95% CI 1.08–5.13) and poorer performance on executive function (−0.39 per SD; p<0.05) but not with TCBV or hippocampal volume.
Carotid atherosclerosis markers were associated with MRI indices of brain ischemia and aging and with cognitive impairment in a community-based sample of middle-aged adults. Our data suggest that ICA-IMT may be a better marker for cognitive impairment than CCA-IMT.
Carotid atherosclerosis; brain MRI; cognitive performance
Shear stress gradients and inflammation have been causally associated with atherosclerosis development in carotid bifurcation regions. The mechanism underlying higher levels of carotid intima-media thickness observed among HIV-infected individuals remains unknown.
Methods and Results
We measured carotid intima-media thickness progression and development of plaque in the common carotid, bifurcation region, and internal carotid artery in 300 HIV-infected persons and 47 controls. The median duration of follow-up was 2.4 years. When all segments were included, the rate of intima-media thickness progression was greater in HIV-infected subjects compared with controls after adjustment for traditional risk factors (0.055 vs. 0.024 mm/year, P=0.016). Rate of progression was also greater in the bifurcation region (0.067 vs. 0.025 mm/year, P=0.042) whereas differences were smaller in the common and internal regions. HIV-infected individuals had a greater incidence of plaque compared with controls in the internal (23% vs. 6.4%, P=0.0037) and bifurcation regions (34% vs. 17%, P=0.014). Among HIV-infected individuals, the rate of progression in the bifurcation region was more rapid compared with the common carotid, internal, or mean intima-media thickness; in contrast, progression rates among controls were similar at all sites. Baseline hsCRP was elevated in HIV-infected persons and was a predictor of progression in the bifurcation region.
Atherosclerosis progresses preferentially in the carotid bifurcation region in HIV-infected individuals. hsCRP, a marker of inflammation, is elevated in HIV and is associated with progression in the bifurcation region. These data are consistent with a model in which the interplay between hemodynamic shear stresses and HIV-associated inflammation contribute to accelerated atherosclerosis. (J Am Heart Assoc. 2012;1:jah3-e000422 doi: 10.1161/JAHA.111.000422.)
Clinical Trial Registration
URL: http://clinicaltrials.gov. Unique identifier: NCT01519141
AIDS; carotid arteries; inflammation; atherosclerosis
Intima-media thickness (IMT) provides a surrogate end point of cardiovascular outcomes in clinical trials evaluating the efficacy of cardiovascular risk factor modification. Carotid artery plaque further adds to the cardiovascular risk assessment. It is defined as a focal structure that encroaches into the arterial lumen of at least 0.5 mm or 50% of the surrounding IMT value or demonstrates a thickness >1.5 mm as measured from the media-adventitia interface to the intima-lumen interface. The scientific basis for use of IMT in clinical trials and practice includes ultrasound physics, technical and disease-related principles as well as best practice on the performance, interpretation and documentation of study results. Comparison of IMT results obtained from epidemiological and interventional studies around the world relies on harmonization on approaches to carotid image acquisition and analysis. This updated consensus document delineates further criteria to distinguish early atherosclerotic plaque formation from thickening of IMT. Standardized methods will foster homogenous data collection and analysis, improve the power of randomized clinical trials incorporating IMT and plaque measurements and facilitate the merging of large databases for meta-analyses. IMT results are applied to individual patients as an integrated assessment of cardiovascular risk factors. However, this document recommends against serial monitoring in individual patients.
Intima-media thickness; Carotid plaque; Vascular ultrasound; Randomized clinical trials; Carotid disease; Reference values
Carotid disease is a common finding in patients with coronary artery disease (CAD) and its presence is associated with worse clinical outcomes. Intima-media thickness provides incremental value over traditional risk factors in predicting cardiovascular events; however, it does not predict the absence of CAD or its extent and severity. The presence of carotid plaques is associated with an increased risk of cardiovascular events in patients with CAD regardless of the treatment strategy (medical therapy alone or myocardial revascularization). Hence, we advocate the screening of patients with diagnosed CAD for carotid atherosclerosis. The prognostic impact of ultrasound characteristics of carotid plaques on cardiovascular outcomes of patients with CAD remains controversial.
intima-media thickness; carotid plaques; coronary artery disease; ultrasound
Atherosclerosis is the leading cause of cardiovascular disease (CVD). Traditional risk factors can be used to identify individuals at high risk for developing CVD and are generally associated with the extent of atherosclerosis; however, substantial numbers of individuals at low or intermediate risk still develop atherosclerosis.
A case-control study was performed using microarray gene expression profiling of peripheral blood from 119 healthy women in the Multi-Ethnic Study of Atherosclerosis cohort aged 50 or above. All participants had low (<10%) to intermediate (10% to 20%) predicted Framingham risk; cases (N = 48) had coronary artery calcium (CAC) score >100 and carotid intima-media thickness (IMT) >1.0 mm, whereas controls (N = 71) had CAC<10 and IMT <0.65 mm. We identified two major expression profiles significantly associated with significant atherosclerosis (odds ratio 4.85; P<0.001); among those with Framingham risk score <10%, the odds ratio was 5.30 (P<0.001). Ontology analysis of the gene signature reveals activation of a major innate immune pathway, toll-like receptors and IL-1R signaling, in individuals with significant atherosclerosis.
Gene expression profiles of peripheral blood may be a useful tool to identify individuals with significant burden of atherosclerosis, even among those with low predicted risk by clinical factors. Furthermore, our data suggest an intimate connection between atherosclerosis and the innate immune system and inflammation via TLR signaling in lower risk individuals.
To compare the predictability of the Framingham Risk Score (FRS), United Kingdom Prospective Diabetes Study (UKPDS) risk engine, and the Systematic Coronary Risk Evaluation (SCORE) for carotid atherosclerosis and peripheral arterial disease in Korean type 2 diabetic patients.
Among 1,275 registered type 2 diabetes patients in the health center, 621 subjects with type 2 diabetes participated in the study. Well-trained examiners measured the carotid intima-media thickness (IMT), carotid plaque, and ankle brachial index (ABI). The subject's 10-year risk of coronary heart disease was calculated according to the FRS, UKPDS, and SCORE risk scores. These three risk scores were compared to the areas under the curve (AUC).
The odds ratios (ORs) of all risk scores increased as the quartiles increased for plaque, IMT, and ABI. For plaque and IMT, the UKPDS risk score provided the highest OR (95% confidence interval) at 3.82 (2.36, 6.17) and at 6.21 (3.37, 11.45). For ABI, the SCORE risk estimation provided the highest OR at 7.41 (3.20, 17.18). However, no significant difference was detected for plaque, IMT, or ABI (P = 0.839, 0.313, and 0.113, respectively) when the AUCs of the three risk scores were compared. When we graphed the Kernel density distribution of these three risk scores, UKPDS had a higher distribution than FRS and SCORE.
No significant difference was observed when comparing the predictability of the FRS, UKPDS risk engine, and SCORE risk estimation for carotid atherosclerosis and peripheral arterial disease in Korean type 2 diabetic patients.
Risk Assessment; Peripheral Arterial Disease; Carotid Artery Thrombosis; Diabetes Mellitus, Type 2
Maximum carotid artery wall thickness was utilized in a primary prevention population and compared with baseline risk factors. Carotid wall thickness was measured between the blood–intima and media–adventitia interfaces by B-mode ultrasonography using software calipers at points of protrusion. Long-axis measures were confirmed by short-axis assessment. The maximum carotid wall thickness for each subject was divided by age in years to yield an annual accretion rate (called carotid intima–media thickness accretion rate [CIMTAR]). The entire study population was then divided by median CIMTAR to investigate the association with baseline variables used in standard risk assessments with the bifurcated groups. Traditional risk factors such as age, diabetes, smoking, hyperlipidemia, and obesity were not associated with greater than median CIMTAR. Only male gender (P = 0.02) and systolic blood pressure (P = 0.002) in baseline variables were associated with an elevated CIMTAR for the entire population. Among those not taking lipid-lowering therapy at baseline, only systolic blood pressure remained significant (P = 0.0002). Correlations between low-density lipoprotein (LDL) cholesterol level and maximum carotid wall thickness/CIMTAR were weak for the entire population (r = −0.17/r = −0.12, respectively). Measure of maximum carotid wall thickness may select patients earlier for treatment than traditional risk factors. The addition of CIMTAR to risk algorithms may permit a single-point assignation of subsequent vascular risk that is more efficacious than traditional risk factors.
Atherogenesis; carotid wall thickness; IMT; stroke
To describe and test a practical protocol to measure common carotid intima-media thickness that uses the combined values of two longitudinal examination angles to increase sensitivity.
Between February and September 2005, 206 patients underwent duplex scan examination of carotid vessels, and the intima-media thickness of 407 common carotids were measured in three angles: transversal, longitudinal posterolateral, and anterolateral, with three intima-media thickness measurements for each near and far wall. In addition to numbers obtained from the three angles of measurement, a fourth visual perspective was obtained by combining the intima-media thickness results of posterolateral and anterolateral longitudinal views and considering the thickest wall measurement.
Two hundred seventy (66.3%) carotid arteries had an intima-media thickness thicker than 1mm. The mean intima-media thickness values achieved by the different incidences were 1.26±0.6mm (transversal), 1.17±0.54mm (longitudinal anterolateral), and 1.18±0.58mm (longitudinal posterolateral). A significant difference in intima-media thickness measurement values was observed when the three angles of examination plus the combined positive results of both longitudinal angles were compared by ANOVA (P=0.005). The LSD Post-Hoc test determined that the combined longitudinal view results were similar to the transversal views (P=0.28) and had greater intima-media thickness means than isolated anterolateral or posterolateral longitudinal views (P=0.02 and 0.05, respectively).
The protocol presented is a practical method for obtaining common carotid artery intima-media thickness measurements. The combined longitudinal posterolateral and anterolateral longitudinal views provide a more sensitive evaluation of the inner layers of the carotid walls than isolated longitudinal views.
Intima-media thickness; Carotid artery; Protocol; Atherosclerosis; Duplex scan
Carotid intima–media thickness (CIMT) and plaque information can improve coronary heart disease (CHD) risk prediction when added to traditional risk factors (TRF). However, obtaining adequate images of all carotid artery segments (A-CIMT) may be difficult. Of A-CIMT, the common carotid artery intima–media thickness (CCA-IMT) is relatively more reliable and easier to measure. We evaluated whether CCA-IMT is comparable to A-CIMT when added to TRF and plaque information in improving CHD risk prediction in the Atherosclerosis Risk in Communities (ARIC) study.
Methods and results
Ten-year CHD risk prediction models using TRF alone, TRF + A-CIMT + plaque, and TRF + CCA-IMT + plaque were developed for the overall cohort, men, and women. The area under the receiver operator characteristic curve (AUC), per cent individuals reclassified, net reclassification index (NRI), and model calibration by the Grønnesby–Borgan test were estimated. There were 1722 incident CHD events in 12 576 individuals over a mean follow-up of 15.2 years. The AUC for TRF only, TRF + A-CIMT + plaque, and TRF + CCA-IMT + plaque models were 0.741, 0.754, and 0.753, respectively. Although there was some discordance when the CCA-IMT + plaque- and A-CIMT + plaque-based risk estimation was compared, the NRI and clinical NRI (NRI in the intermediate-risk group) when comparing the CIMT models with TRF-only model, per cent reclassified, and test for model calibration were not significantly different.
Coronary heart disease risk prediction can be improved by adding A-CIMT + plaque or CCA-IMT + plaque information to TRF. Therefore, evaluating the carotid artery for plaque presence and measuring CCA-IMT, which is easier and more reliable than measuring A-CIMT, provide a good alternative to measuring A-CIMT for CHD risk prediction.
CIMT; Plaque; Risk prediction
The measurement of carotid intima-medial thickness is a well validated measure of cardiovascular risk. Although atherosclerosis occurs in the intima, this arterial layer is not measured alone due to limitation in ultrasound resolution with standard frequency probes.
We evaluated the feasibility of using a 55-MHz ultrasound system with high resolution to measure intima thickness in several vascular territories compared to a “standard” frequency probe.
The intima and medial thickness was measured in the brachial, radial and tibial arteries in 10 healthy subjects and 5 subjects with peripheral arterial disease. The high frequency ultrasound probe showed superior resolution compared to the standard frequency probe allowing for measurement of intima separately from media.
The intima can be measured independently of media with a high degree of reproducibility using a high frequency probe. This technology may allow for early detection of cardiovascular risk and extend knowledge about the physiological changes in the early atherosclerotic development.
To evaluate the association between carotid intima-media thickness (CIMT) and the presence of aortic arch plaques (AP) in a community-based cohort.
Large AP are associated with ischemic stroke. CIMT is a marker of subclinical atherosclerosis and a strong predictor of cardiovascular disease and stroke. The association between CIMT and AP has been studied in stroke patients, but not in the general population. Aim of this study was to investigate this association in an elderly asymptomatic cohort, and the possibility to use CIMT to predict the presence or absence of large AP.
Stroke-free control subjects from the Aortic Plaque and Risk of Ischemic Stroke (APRIS) Study underwent transesophageal echocardiography and high-resolution B-mode ultrasound of the carotid arteries. CIMT was measured at the common carotid artery, bifurcation and internal carotid artery. The association between CIMT and AP was analyzed by multivariate regression models. Positive and negative predictive values of CIMT for large (≥ 4 mm) AP were calculated.
Among 138 subjects, large AP was present in 35 (25.4%) subjects. Only CIMT at the bifurcation was associated with large AP after adjustment for atherosclerotic risk factors (p=0.007). Positive and negative predictive value for AP ≥ 4 mm of CIMT at the bifurcation above the 75th percentile (≥ 0.95 mm) were 42% and 80%, respectively. Negative predictive value increased to 87% when the median CIMT value (0.82 mm) was used.
CIMT at the bifurcation is independently associated with AP ≥ 4 mm. Its strong negative predictive value for large arch plaque indicates that CIMT may be used as an initial screening test to exclude severe arch atherosclerosis in the general population.