Clinical and research applications of carotid intima-media thickness

The influence of vigorous physical exertion on cardiac demand under conditions of daily living among firefighters with elevated blood pressure

BACKGROUND

Firefighters have a high prevalence of cardiovascular disease. The poor heart health of firefighters is implicated in their increased risk of sudden cardiac death (SCD). Exercise may be protective against SCD partially due to the immediate blood pressure (BP) reductions of 5-8 mmHg following exercise, termed postexercise hypotension (PEH) OBJECTIVES: To examine PEH under ambulatory conditions after a maximal cardiopulmonary exercise test (CPET) among career firefighters METHODS: Firefighters (n = 19) completed a maximal CPET and non-exercise control (CONTROL) in random order on separate non-workdays and left the laboratory instrumented to an ambulatory BP (ABP) monitor. Ambulatory systolic BP (ASBP), diastolic BP (ADBP), and heart rate (AHR) were recorded at hourly intervals over 19hr. The ambulatory rate pressure product (ARPP) was calculated as ASBPxAHRx10-3 at each hourly interval. Repeated measures ANCOVA tested if the ABP, AHR, and ARPP responses differed after CPET vs CONTROL over 19hr RESULTS: Firefighters were middle-aged (39.5 ± 8.9 yr), overweight (29.2 ± 4.0 kg/m2) men with elevated BP (123.1 ± 9.6/79.8 ± 10.4 mmHg), while resting HR (67.7 ± 11.3 bpm) and RPP (8.4 ± 1.7mmHg*bpm*10-3) were in normal ranges. ASBP (16.6 ± 5.7 mmHg) and ADBP (3.1 ± 4.6 mmHg) increased after the CPET vs CONTROL over 19hr (ps<0.01), as did AHR (9.4 ± 7.9 bpm, p = 0.02) and ARPP (2.5 ± 1.1mmHg*bpm*10-3, p < 0.01).

CONCLUSIONS

Unexpectedly, the firefighters exhibited postexercise hypertension rather than PEH. The increases in ABP and AHR we observed indicated a sustained increase in cardiac demand. Further investigation is needed to confirm our findings and determine whether the adverse hemodynamic responses we observed contribute to the high prevalence of SCD that firefighters experience on the job.

Associations between insulin resistance indices and subclinical atherosclerosis: A contemporary review

Even in the absence of hyperglycemia or hyperlipidemia, it has been demonstrated that insulin resistance is an independent risk factor for atherosclerosis. Finding markers of insulin resistance that are associated with markers of atherosclerosis could help identify patients early in their disease course and allow for earlier initiation of preventative treatments. We reviewed available evidence regarding associations between known markers of insulin resistance and known markers of atherosclerosis. Serum triglycerides (TG), triglyceride-glucose index (TyG), and homeostasis model assessment (HOMA) were the insulin resistance markers reviewed. The coronary artery calcium score (CAC), carotid intimal medium thickness (cIMT), and pulse wave velocity (PWV) were reviewed as markers of atherosclerosis. TyG showed the most consistent association with CAC across broad demographic groups, though HOMA showed potential in obese individuals and those without diabetes. The data regarding cIMT and the reviewed insulin resistance markers did not yield any consistent associations, though very elevated TyG did appear to be associated with cIMT among normal weight individuals. Serum triglycerides showed a strong and consistent association with PWV across numerous studies and populations, though TyG index also demonstrated a strong association with PWV in a large systematic review. Of the insulin resistance markers reviewed, the TyG index appears to be most consistently associated with markers of atherosclerosis. TyG can be easily calculated with routine labwork and has the potential to inform decisions regarding early initiation of therapies in patients who would otherwise not be treated. Targeting insulin sensitivity prior to the development of T2DM has the potential to reduce development and progression of atherosclerosis, and patients without T2DM but who have elevated TyG index should be the topic of further research.

Atherosclerosis and depression: is carotid intima-media thicker in patients with depression compared to matched control individuals? A systematic review and meta-analysis

OBJECTIVE

To investigate if there is an association between atherosclerosis and depression by using as imaging biomarker the carotid intima media thickness (cIMT), a surrogate marker for atherosclerosis.

METHODS

PubMed/Medline, Embase and Cochrane databases were comprehensively searched to identify studies investigating the association between cIMT and depression. The results were pooled using a random-effects statistical model, appropriate for the expected high heterogeneity. Sensitivity and subgroup analyses were conducted where data was available.

RESULTS

Overall, 22 and 13 studies met inclusion criteria for the qualitative and the quantitative synthesis, respectively, with a total of 4466 patients and 21,635 control participants. Results showed that cIMT is significantly higher in the depression, compared to the control groups with an overall mean difference of 0.07 mm (95% CI 0.04-0.10, p < 0.01). Subgroup analysis showed that diabetes could present as a confounding factor in patients with depression and an increased cIMT.

CONCLUSIONS

This study confirms a significantly increased cIMT in patients with depression, compared with controls and suggests a possible bidirectional link between atherosclerosis and depression. An early screening of cardiovascular disease in individuals suffering with depression should be considered.

Carotid intima media thickness (CIMT) in adults in the AWI-Gen Nairobi site study: Profiles and predictors

BACKGROUND

Carotid intima media thickness (CIMT) is used as a marker of subclinical and asymptomatic atherosclerotic vascular disease. Increased CIMT is associated with future cerebrovascular and cardiovascular events. There is limited data on the profile and correlates of CIMT in Africa. The aim of this study was to describe the profile and correlates of CIMT in apparently normal younger-age adults in an urban setting in Kenya.

METHODS

This study used population-based data collected from 2003 adults between the ages of 40 and 60 years in two slums of Nairobi as part of a genetic study. CIMT was measured using LOGIQ e (GE Healthcare, CT, USA) ultrasound on both left and right carotid arteries, whereby maximum, mean, and minimum values were recorded. Age- and sex-specific CIMT measurements were calculated and their association with basic sociodemographic, behavioral and body composition indicators were investigated.

RESULTS

The median (IQR) CIMT were 0.58 (0.51, 0.66) and 0.59 (0.53, 0.66) in men and women, respectively. About 16% of the study population had CIMT greater than 0.7mm, the cut off for higher CIMT. Nearly 60% had CIMT values ≥75th percentile. Age, current use of alcohol, systolic blood pressure, subcutaneous fat thickness, pulse rate and pulse pressure were found to be the main predictors of CIMT in our study population.

CONCLUSION

This study provided population-based reference values and predictors for CIMT for an adult population living in urban poor settings in Kenya. Future studies need to consider biochemical and genetic predictors of CIMT in this population.

Serum vaspin levels and carotid intima-media thickness in predialysis patients

BACKGROUND AND OBJECTIVE

Visceral adipose tissue-derived serine proteinase inhibitor (vaspin) is an adipokine that correlates with insulin resistance and obesity in human beings. Previous studies have evaluated the serum vaspin levels in several diseases such as chronic haemodialysis patients and coronary artery disease. To our knowledge, serum vaspin levels have not yet been reported in predialysis patients. Carotid intima-media thickness (CIMT) is a noninvasive procedure to detect early atherosclerotic changes. The aim of this study was to evaluate serum vaspin levels in predialysis patients and their relationships with glomerular filtration rate and CIMT levels.

METHODS

A total of twenty-five predialysis patients (14 females and 11 males) and 22 healthy subjects (8 females and 14 males) were enrolled in the study. Serum samples were subjected to the human vaspin RIA system. CIMT was measured by B-mode ultrasonography.

RESULTS

Serum vaspin levels were significantly lower in predialysis patients than control subjects (P < .05), while CIMT levels were significantly higher (P < .001). Serum vaspin levels were found to be significantly correlated with glomerular filtration rate (r = 0.42, P < .001) and CIMT (r = -0.47, P < .05) in predialysis patients.

CONCLUSIONS

This is the first report to describe the association between serum vaspin levels and CIMT in predialysis patients. We concluded that serum vaspin levels were decreased in predialysis patients than control subjects. In addition, serum vaspin levels were found to be significantly correlated with glomerular filtration rate and CIMT.

Obstructive sleep apnea risk and subclinical atherosclerosis in South Asians living in the United States

OBJECTIVES

The objective of this study was to examine the association between high risk of obstructive sleep apnea (OSA) and subclinical atherosclerosis among South Asians in the United States.

DESIGN

A secondary analysis of cross-sectional data.

SETTING/PARTICIPANTS

A community-based cohort of 906 men and women participating in the Mediators of Atherosclerosis in South Asians Living in America (MASALA) study.

MEASUREMENTS

The Berlin Questionnaire was used to screen for OSA risk. Coronary artery calcium (CAC), common carotid artery intima-media thickness (IMT), and internal carotid artery IMT were used as measures of subclinical atherosclerosis.

RESULTS

The majority of participants (59%) with high OSA risk had CAC scores >0 compared with only 41% of participants with low OSA risk (P <.001). The high OSA risk group was older (P =.005), male (P =.04), had higher body mass index (P <.001) and had greater common carotid artery IMT (0.96 ± 0.27 mm) and internal carotid artery IMT (1.33 ± 0.42 mm) measurements. Snoring, sleep-disordered breathing (SDB), and high OSA risk were associated with subclinical atherosclerosis. However, only high OSA risk remained significant in multivariable models after controlling for demographic and clinical factors that included hypertension (HTN), obesity, diabetes, and dyslipidemia.

CONCLUSIONS

High OSA risk, which includes overlapping comorbidities of HTN and obesity, was not associated with the time living in the US but was associated with subclinical atherosclerosis markers. These cardiovascular disease risk factors should include evaluation of the spectrum of SDB among all adults, including South Asian men and women.

Cardiovascular injury induced by tobacco products: assessment of risk factors and biomarkers of harm. A Tobacco Centers of Regulatory Science compilation

Although substantial evidence shows that smoking is positively and robustly associated with cardiovascular disease (CVD), the CVD risk associated with the use of new and emerging tobacco products, such as electronic cigarettes, hookah, and heat-not-burn products, remains unclear. This uncertainty stems from lack of knowledge on how the use of these products affects cardiovascular health. Cardiovascular injury associated with the use of new tobacco products could be evaluated by measuring changes in biomarkers of cardiovascular harm that are sensitive to the use of combustible cigarettes. Such cardiovascular injury could be indexed at several levels. Preclinical changes contributing to the pathogenesis of disease could be monitored by measuring changes in systemic inflammation and oxidative stress, organ-specific dysfunctions could be gauged by measuring endothelial function (flow-mediated dilation), platelet aggregation, and arterial stiffness, and organ-specific injury could be evaluated by measuring endothelial microparticles and platelet-leukocyte aggregates. Classical risk factors, such as blood pressure, circulating lipoproteins, and insulin resistance, provide robust estimates of risk, and subclinical disease progression could be followed by measuring coronary artery Ca2+ and carotid intima-media thickness. Given that several of these biomarkers are well-established predictors of major cardiovascular events, the association of these biomarkers with the use of new and emerging tobacco products could be indicative of both individual and population-level CVD risk associated with the use of these products. Differential effects of tobacco products (conventional vs. new and emerging products) on different indexes of cardiovascular injury could also provide insights into mechanisms by which they induce cardiovascular harm.

Assessing the Relationship between Atherosclerotic Cardiovascular Disease Risk Score and Carotid Artery Imaging Findings

BACKGROUND AND PURPOSE

To characterize the relationship between computed tomography angiography (CTA) imaging characteristics of carotid artery and the 10-year risk of atherosclerotic cardiovascular disease (ASCVD) score.

METHODS

We retrospectively identified all patients who underwent a cervical CTA at our institution from January 2013 to July 2016, extracted clinical information, and calculated the 10-year ASCVD score using the Pooled Cohort Equations from the 2013 ACC/AHA guidelines. We compared the imaging features of artery atherosclerosis derived from the CTAs between low and high risk.

RESULTS

One hundred forty-six patients met our inclusion criteria. Patients with an ASCVD score ≥7.5% (64.4%) had significantly more arterial stenosis than patients with an ASCVD score <7.5% (35.6%, P < .001). Maximal plaque thickness was significantly higher (mean 2.33 vs. .42 mm, P < .001) and soft plaques (55.3% vs. 13.5%, P < .001) were significantly more frequent in patients with an ASCVD score ≥7.5%. However, among patients with a 10-year ASCVD score ≥7.5%, 33 (35.1%) had no arterial stenosis, 35 (37.2%) had a maximal plaque thickness less than. 9 mm, and 42 (44.7%) had no soft plaque. Furthermore, among the patients with a 10-year ASCVD score <7.5%, 8 (15.4%) had some arterial stenosis, 8 (15.4%) had a maximal plaque thickness more than. 9 mm, and 7 (13.5%) had soft plaque.

CONCLUSION

There is some concordance but not a perfect overlap between the 10-year ASCVD risk scores calculated from clinical and blood assessment and carotid artery imaging findings.

Effects of a liquefied petroleum gas stove intervention on pollutant exposure and adult cardiopulmonary outcomes (CHAP): study protocol for a randomized controlled trial

BACKGROUND

Biomass fuel smoke is a leading risk factor for the burden of disease worldwide. International campaigns are promoting the widespread adoption of liquefied petroleum gas (LPG) in resource-limited settings. However, it is unclear if the introduction and use of LPG stoves, in settings where biomass fuels are used daily, reduces pollution concentration exposure, improves health outcomes, or how cultural and social barriers influence the exclusive adoption of LPG stoves.

METHODS

We will conduct a randomized controlled, field intervention trial of LPG stoves and fuel distribution in rural Puno, Peru, in which we will enroll 180 female participants aged 25-64 years and follow them for 2 years. After enrollment, we will collect information on sociodemographic characteristics, household characteristics, and cooking practices. During the first year of the study, LPG stoves and fuel tanks will be delivered to the homes of 90 intervention participants. During the second year, participants in the intervention arm will keep their LPG stoves, but the gas supply will stop. Control participants will receive LPG stoves and vouchers to obtain free fuel from distributors at the beginning of the second year, but gas will not be delivered. Starting at baseline, we will collect longitudinal measurements of respiratory symptoms, pulmonary function, blood pressure, endothelial function, carotid artery intima-media thickness, 24-h dietary recalls, exhaled carbon monoxide, quality-of-life indicators, and stove-use behaviors. Environmental exposure assessments will occur six times over the 2-year follow-up period, consisting of 48-h personal exposure and kitchen concentration measurements of fine particulate matter and carbon monoxide, and 48-h kitchen concentrations of nitrogen dioxide for a subset of 100 participants.

DISCUSSION

Findings from this study will allow us to better understand behavioral patterns, environmental exposures, and cardiovascular and pulmonary outcomes resulting from the adoption of LPG stoves. If this trial indicates that LPG stoves are a feasible and effective way to reduce household air pollution and improve health, it will provide important information to support widespread adoption of LPG fuel as a strategy to reduce the global burden of disease.

TRIAL REGISTRATION

ClinicalTrials.gov, ID: NCT02994680 , Cardiopulmonary Outcomes and Household Air Pollution (CHAP) Trial. Registered on 28 November 2016.

The relationship between HbA₁c and ultrasound plaque textures in atherosclerotic patients

Objective

Diabetes mellitus (DM) is associated to the morphological and componential characteristics of atheromatous plaques. It has proven that plaque textures are related to plaque components and beneficial for atherosclerotic risk stratification. The aim of this study is to compare plaque textures in patients with and without DM, and examine the relationship between HbA_1c levels and the ultrasound plaque textures in atherosclerotic patients.

Methods

A total of 136 participants (among them 66 are diabetic and 70 are non-diabetic) suffering from carotid plaques were included. About 300 texture features were extracted from the ultrasound images of plaques using the algorithms of histogram, absolute gradient, run-length matrix, gray-level co-occurrence matrix, autoregressive model and wavelet transform, respectively. Thirty optimal features were selected by the Fisher coefficient and the mutual information measure. The most discriminating feature (MDF) was obtained from the linear discriminant analysis for the optimal features. Linear regression model was performed to investigate the relationship between HbA_1c and MDF. The receiver operating characteristics (ROC) curve was further developed to validate the relation between the estimated HbA_1c (models output) and diabetes status.

Results

A total of 12 texture features showed statistical difference between patients with and without DM. The MDF was significant higher in non-diabetic patients (0.326 ± 0.049) than diabetic patients (−0.346 ± 0.052) (p < 0.001). The optimal regression model (r = 0.348, p < 0.001) for HbA_1c included a constant (p < 0.001) and the MDF (p < 0.001). The areas under ROC curve used to estimate HbA_1c was 0.828.

Conclusions

The results indicate that there is a quantitative relationship between the HbA_1c levels and plaque textures in ultrasonic images of atherosclerotic patients, which may suggest that texture analysis of the ultrasonic image of plaque is a promising method for evaluating the cardiovascular risk caused by DM in patients with plaques.

Role of Coronary Artery Calcium Score of Zero and Other Negative Risk Markers for Cardiovascular Disease: The Multi-Ethnic Study of Atherosclerosis (MESA)

BACKGROUND

Limited attention has been paid to negative cardiovascular disease (CVD) risk markers despite their potential to improve medical decision making. We compared 13 negative risk markers using diagnostic likelihood ratios (DLRs), which model the change in risk for an individual after the result of an additional test.

METHODS AND RESULTS

We examined 6814 participants from the Multi-Ethnic Study of Atherosclerosis. Coronary artery calcium score of 0, carotid intima-media thickness <25th percentile, absence of carotid plaque, brachial flow-mediated dilation >5% change, ankle-brachial index >0.9 and <1.3, high-sensitivity C-reactive protein <2 mg/L, homocysteine <10 µmol/L, N-terminal pro-brain natriuretic peptide <100 pg/mL, no microalbuminuria, no family history of coronary heart disease (any/premature), absence of metabolic syndrome, and healthy lifestyle were compared for all and hard coronary heart disease and all CVD events over the 10-year follow-up. Models were adjusted for traditional CVD risk factors. Among all negative risk markers, coronary artery calcium score of 0 was the strongest, with an adjusted mean DLR of 0.41 (SD, 0.12) for all coronary heart disease and 0.54 (SD, 0.12) for CVD, followed by carotid intima-media thickness <25th percentile (DLR, 0.65 [SD, 0.04] and 0.75 [SD, 0.04], respectively). High-sensitivity C-reactive protein <2 mg/L and normal ankle-brachial index had DLRs >0.80. Among clinical features, absence of any family history of coronary heart disease was the strongest (DLRs, 0.76 [SD, 0.07] and 0.81 [SD, 0.06], respectively). Net reclassification improvement analyses yielded similar findings, with coronary artery calcium score of 0 resulting in the largest, most accurate downward risk reclassification.

CONCLUSIONS

Negative results of atherosclerosis-imaging tests, particularly coronary artery calcium score of 0, resulted in the greatest downward shift in estimated CVD risk. These results may help guide discussions on the identification of individuals less likely to receive net benefit from lifelong preventive pharmacotherapy.

Assessment and relevance of carotid intima-media thickness (C-IMT) in primary and secondary cardiovascular prevention

Interventions aimed to prevent cardiovascular diseases (CVD) are more effective if administered to subjects carefully selected according to their CVD risk. Usually, this risk is evaluated on the basis of the presence and severity of conventional vascular risk factors (VRFs); however, atherosclerosis, the main pathologic substrate of CVD, is not directly revealed by VRFs. The measurement of the arterial wall, using imaging techniques, has increased the early identification of individuals prone to develop atherosclerosis and to quantify its changes over time.

B-mode ultrasound is a technique which allows a non-invasive assessment of the arterial wall of peripheral arteries (e.g. extracranial carotid arteries), and provides measures of the intima-media thickness complex (C-IMT) and additional data on the occurrence, localization and morphology of plaques.

Being an independent predictor of vascular events, C-IMT has been considered as a tool to optimize the estimation of CVD risk but this application is still a matter of debate. Though the technique is innocuous, relatively inexpensive and repeatable, its use in the clinical practice is limited by the lack of standardized protocols and clear guidelines.

This review outlines the rationale for the potential use of C-IMT in the stratification of cardio- and cerebro-vascular risk and discusses several topics related to the measurement of this variable, which are still controversial among experts of the field.

Carotid atherosclerotic disease predicts cardiovascular events in hemodialysis patients: a prospective study

Background

To evaluate the predictive value of carotid atherosclerotic disease (CAD) and intima-media thickness (IMT) on incident cardiovascular disease and mortality in hemodialysis patients.

Methods

Multicenter, observational, prospective study including 110 patients, followed-up to 6 years. Carotid doppler ultrasonographic findings were classified in 4 degrees of severity: 1) IMT <0.9 mm, 2) IMT >0.9 mm, 3) carotid plaque with stenosis <50% and 4) plaque with stenosis >50%. The associations between IMT and CAD and cardiovascular events, total and cardiovascular mortality were assessed.

Results

83% of the patients had atherosclerotic plaques (CAD degrees 3-4). During follow-up, 29.1% of patients experienced cardiovascular events, and 28.2% died, 38.7% of cardiovascular origin. The presence of plaques was associated with cardiovascular events (p = 0.03) while calcified plaques were associated with both cardiovascular events (p = 0.01), cardiovascular mortality (p = 0.03) and non-significantly with overall mortality (p = 0.08) in the survival analysis. Carotid IMT was not associated with outcomes. Cardiovascular events correlated with CAD severity (HR 2.27, 95% CI 1.13-4.54), age (HR 1.04, 1.01-1.06), previous cardiovascular disease (HR 1.75, 1.05-4.42), dyslipidemia (HR 2.25, 1.11-4.53), lipoprotein (a) (HR 1.01, 1.00-1.02), troponin I (HR 3.89, 1.07-14.18), fibrinogen levels (HR 1.38, 0.98-1.94) and antiplatelet therapy (HR 2.14, 1.04-4.4). In an age-adjusted multivariate model, cardiovascular events were independently associated with previous coronary artery disease (HR 3.29, 1.52-7.15) and lipoprotein (a) (HR 1.01, 1.00-1.02).

Conclusions

The presence of carotid plaques and, especially, calcified plaques, are predictors of new cardiovascular events and cardiovascular mortality in hemodialysis patients, while IMT was not. The prognostic value of calcified plaques should be confirmed in future studies.

Evaluation of carotid artery elasticity changes in patients with type 2 diabetes

BACKGROUND

Type 2 diabetes is one of the most common causes of cardiovascular disease as it causes arterial stiffness changes. The purpose of this study is to characterize, in vivo, carotid arterial structural and functional changes by applying radio frequency and X-strain ultrasound techniques.

METHODS

Ninety-one subjects were assigned into two groups; a diabetes group and a control group. Structural and functional changes in the common carotid arterial wall were investigated by quality intima-media thickness (QIMT), quality arterial stiffness (QAS), and X-strain analysis with a Mylab Twice ultrasound instrument. The relationships among variables between the two groups were analyzed in this study.

RESULTS

There was no significant difference in carotid IMT (626.5 ± 169.1 μm vs. 568.5 ± 122.6 μm, P = 0.1506) between two groups. Pulse wave velocity (PWV) and stiffness index (β) were remarkably greater (8.388 ± 3.254 m/s vs. 7.269 ± 1.332 m/s; 12.51 ± 14.16 vs.9.279 ± 2.871), while compliance coefficient (CC) decreased significantly in the diabetes group (0.802 ± 0.3094 mm2/Kpa vs. 0.968 ± 0.3992 mm2/Kpa) (P < 0.05). The displacement difference of radial (RD-D), longitudinal (LD-D) and rotation (ROT-D) directions were significantly different between two groups' comparison (P = 0.0212, P = 0.0235 and P = 0.0072, respectively). The time of circumferential peak strain difference (CS-DT) and the time of radial peak strain rate (RSR-T) were found to be significantly different between the two groups (341.9 ± 77.56 ms vs. 369.0 ± 78.26 ms, P = 0.0494; 142.7 ± 22.43 ms vs. 136.2 ± 30.70 ms, P = 0.0474). CS-TD and RSR-T were also found to be positively correlated with CC value (r = 0.3908, P < 0.005 and r = 0.3027, P = 0.0326, respectively). Finally, PWV was negatively correlated with CC with (r = -0.6177, P < 0.001).

CONCLUSIONS

In type 2 diabetes, the functional changes in CCA can be identified using the methods presented in this article earlier than the structural changes. Arterial stiffness values provided by QAS and X-strain analysis can be used as indicators of CCA functional lesions in patients with type 2 diabetes.

Patients with obstructive sleep apnea display increased carotid intima media: a meta-analysis

Background. Obstructive sleep apnea (OSA) is associated with coronary artery disease. Intermittent hypoxia associated with OSA increases sympathetic activity and may cause systemic inflammation, which may contribute to atherosclerosis leading to an increase in the size of carotid intima media thickness (CIMT). Methods. PubMed and Cochrane library were reviewed by utilizing different combinations of key words: sleep apnea, carotid disease, intima media thickness, and carotid atherosclerosis. Inclusion criteria were English articles; studies with adult population with OSA and without OSA; CIMT recorded by ultrasound in mean and standard deviation or median with 95% confidence interval; and OSA defined as apnea hypopnea index of ≥5/h. A total of 95 studies were reviewed for inclusion, with 16 studies being pooled for analysis. Results. Ninety-five studies were reviewed, while 16 studies were pooled for analysis; since some studies have more than one data set, there were 25 data sets with 1415 patients being pooled for meta-analysis. All studies used ultrasound to measure CIMT. CIMT standardized difference in means ranged from -0.883 to 8.01. The pooled standardized difference in means was 1.40 (lower limit 0.996 to upper limit 1.803, (P < 0.0001). Conclusion. Patients with OSA appear to have increased CIMT suggestive of an atherosclerotic process.

Future non-invasive imaging to detect vascular plaque instability and subclinical non-obstructive atherosclerosis

Atherosclerosis underlies the major causes of death in the Western World. Our main goal is to detect early changes of atherosclerosis and to identify subjects at highest cardiovascular risk that may aid in the development of prevention approaches and better management that will decrease cardiovascular morbidity and mortality. The new methods that are of interest include the advanced vascular ultrasound methods, the infra red and near infra red imaging techniques, the EndoPat device that reflects peripheral arterial tone, the electron beam computed tomography, the magnetic resonance imaging, and the molecular imaging techniques. In this review we will focus on the future of advanced imaging techniques that are being developed to detect early (pre-clinical) development of atherosclerosis.

Risk factors for subclinical atherosclerosis in diabetic and obese children

BACKGROUND

Increased carotid intima-media thickness (cIMT) is considered a marker of early-onset atherosclerosis and it seems to predict cardiovascular events both in obese and diabetic subjects. We aimed to evaluate early signs of atherosclerosis and investigate for predisposing factors in children and adolescents affected by type 1 diabetes (T1DM) or obesity, comparing them with healthy controls.

METHODS

Out of 71 enrolled subjects (mean age 12.8 ± 2.3 years), 26 had T1DM and 24 were obese, while 21 age- and sex-matched subjects acted as controls. cIMT was measured using standardized methods. Serum glucose, insulin, cholesterol, triglycerides and C-reactive protein levels were evaluated. An oral glucose tolerance test (OGTT) was performed in obese subjects.

RESULTS

Diabetic and obese individuals showed higher cIMT mean values than healthy controls (p < 0.005). cIMT of the three examined segments correlated positively with fasting glucose levels and negatively with units of insulin/kg/day administered in T1DM individuals. A positive correlation between insulin levels (basal and after oral glucose load) and cIMT of common, internal and external carotid artery was found in obese subjects (p < 0.03). High density cholesterol levels represented a protective factor for cIMT in this latter group of the study population.

CONCLUSIONS

Our findings show that cIMT correlates with high insulin levels (a sign of insulin resistance) in obese patients and with high fasting glucose levels (a sign of relative insulin deficiency) in T1DM subjects, confirming the need of reducing hyperinsulinism and monitoring blood glucose levels in these subjects to prevent atherosclerosis.

Intima-medial thickness homogeneity in the common carotid artery: measurement method and preliminary clinical study

BACKGROUND

To propose and test in a preliminary clinical study a novel method for calculating intima-medial thickness (IMT) homogeneity (IMTH).

METHODS

IMT was measured off-line on every horizontal pixel line along the far wall of the common carotid artery, with previously validated software. IMTH was assessed by the SD, coefficient of variation, and interval distribution of obtained IMT values. This method was applied to 129 individuals (age, 40-60 years), including 49 healthy control subjects, 44 subjects at high risk of atherosclerosis, and 36 subjects with known atherosclerosis. Differences with a p value <0.05 were considered statistically significant.

RESULTS

SD and coefficient of variation were higher in the high-risk than in the control group, as well as in high-risk and control subgroups with maximal IMT = 0.8 mm or mean IMT = 0.55-0.65 mm. There were 85.7, 62.8, and 36% of IMT values in the 0.4- to 0.6-mm range and 0.89, 13.8, and 21.2% of IMT values in the 0.8- to 1.2-mm range in the control, high-risk, and atherosclerosis groups, respectively.

CONCLUSIONS

IMTH is a promising approach for the assessment of atherosclerosis, in addition to conventional IMT measurement. Further clinical studies are needed to assess its clinical usefulness.

Lactation and maternal subclinical cardiovascular disease among premenopausal women

OBJECTIVE

The objective of the study was to examine the association between lactation and maternal subclinical cardiovascular disease.

STUDY DESIGN

The Women and Infants Study of Healthy Hearts enrolled 607 mothers who delivered a singleton between 1997 and 2002. In 2007, participating mothers underwent measurements of carotid intima-media thickness, lumen diameter, adventitial diameter, and carotid-femoral pulse wave velocity. Multivariable linear and logistic regressions were used to estimate the associations between lactation and subclinical cardiovascular disease.

RESULTS

Compared with mothers who breastfed for 3 or more months after every birth, mothers who never breastfed exhibited a 0.13 mm larger lumen diameter (95% confidence interval, 0.04-0.22) and a 0.12 mm larger adventitial diameter (95% confidence interval, 0.02-0.22) in models adjusting for age, parity, birth outcome, sociodemographic variables, health-related behaviors, family history, gestational weight gain, early adult body mass index, current body mass index, C-reactive protein, blood pressure, cholesterol, triglyceride, high-density lipoprotein, glucose, and insulin levels.

CONCLUSION

Mothers who do not breastfeed have vascular characteristics associated with a greater risk of cardiovascular disease.

Detection of subclinical atherosclerosis in familial hypercholesterolemia using non-invasive imaging modalities

OBJECTIVES

To investigate the extent of subclinical atherosclerosis in asymptomatic familial hypercholesterolemia (FH) patients using non-invasive images techniques.

PATIENTS, METHODS AND RESULTS

The atherosclerotic burden of 36 molecularly defined FH patients (18 males, 45.7±10.9 years) without evidence of cardiovascular disease receiving lipid-lowering treatment and 19 (47.8±11.3 years) controls was investigated. Descending thoracic aorta magnetic resonance imaging (MRI) was performed in a 1.5 T equipment with T1 and T2 sequences to characterize atherosclerotic plaques and to measure aortic wall volumen. Carotid intima-media thickness (cIMT) and presence of plaques were measured using B-mode carotid ultrasound. Mean aortic wall volumen, cIMT and atherosclerotic plaques in aorta were significantly higher in FH cases (P<0.001). A significant correlation between aortic wall volume and cIMT was observed (P<0.01). Aortic MRI detected plaques in 94% and carotid ultrasound in 14% of cases. Lipid-rich plaques were observed only in FH cases (33%) and were associated with family history of premature coronary artery disease (P<0.05).

CONCLUSIONS

Asymptomatic middle-aged FH patients have significantly higher atherosclerotic burden than controls. cIMT has shown a significant correlation with aortic wall volume and MRI allowed the detection of lipid-rich plaques in FH subjects that were associated with family history of premature coronary artery disease.

What the radiologist needs to know about the diabetic patient

Diabetes mellitus (DM) is recognised as a major health problem. Ninety-nine percent of diabetics suffer from type 2 DM and 10% from type 1 and other types of DM. The number of diabetic patients worldwide is expected to reach 380 millions over the next 15 years. The duration of diabetes is an important factor in the pathogenesis of complications, but other factors frequently coexisting with type 2 DM, such as hypertension, obesity and dyslipidaemia, also contribute to the development of diabetic angiopathy. Microvascular complications include retinopathy, nephropathy and neuropathy. Macroangiopathy mainly affects coronary arteries, carotid arteries and arteries of the lower extremities. Eighty percent of deaths in the diabetic population result from cardiovascular incidents. DM is considered an equivalent of coronary heart disease (CHD). Stroke and peripheral artery disease (PAD) are other main manifestations of diabetic macroangiopathy. Diabetic cardiomyopathy (DC) represents another chronic complication that occurs independently of CHD and hypertension. The greater susceptibility of diabetic patients to infections completes the spectrum of the main consequences of DM. The serious complications of DM make it essential for physicians to be aware of the screening guidelines, allowing for earlier patient diagnosis and treatment.

Sex differences in early carotid atherosclerosis (from the community-based Gutenberg-Heart Study)

The objectives of this study were to describe gender differences in intima-media thickness (IMT) in a community-based population study and to define normal IMT values for healthy men and women. In total, 4,814 participants (aged 35 to 74 years; 2,433 men, 2,381 women) from the Gutenberg-Heart Study (GHS) were included. IMT was measured at both common carotid arteries using an edge detection system. Median IMT was 0.62 mm (25th percentile 0.55, 75th percentile 0.70) in women and 0.65 mm (25th percentile 0.57, 75th percentile 0.75) in men and was significantly associated with age (p <0.0001). On multivariate analysis, advanced age, smoking, and arterial hypertension were positively associated with higher IMT in men and women. A subgroup of 1,025 subjects without cardiovascular risk factors or previous cardiovascular disease was analyzed to define normal IMT values. Nomograms were calculated according to age and gender. For each age group, IMT >95th percentile was defined as abnormal. In this subgroup, gender differences in IMT became nonsignificant at older ages. At the age of 35 years, IMT was 0.71 mm in men and 0.61 mm in women at the 95th percentile. In comparison, at the age of 74 years, IMT at the 95th percentile was 0.90 mm in men and 0.89 mm in women. In conclusion, men had higher carotid IMT than women, but predictors of early carotid atherosclerosis were similar across genders. In young subjects without cardiovascular risk factors, normal values for IMT were lower in women compared with men. In contrast, in older subjects, gender differences in IMT became nonsignificant.

Primary prevention of coronary heart disease: integration of new data, evolving views, revised goals, and role of rosuvastatin in management. A comprehensive survey

A recent explosion in the amount of cardiovascular risk and incipient, undetected subclinical cardiovascular pathology has swept across the globe. Nearly 70% of adult Americans are overweight or obese; the prevalence of visceral obesity stands at 53% and continues to rise. At any one time, 55% of the population is on a weight-loss diet, and almost all fail. Fewer than 15% of adults or children exercise sufficiently, and over 60% engage in no vigorous activity. Among adults, 11%-13% have diabetes, 34% have hypertension, 36% have prehypertension, 36% have prediabetes, 12% have both prediabetes and prehypertension, and 15% of the population with either diabetes, hypertension, or dyslipidemia are undiagnosed. About one-third of the adult population, and 80% of the obese, have fatty livers. With 34% of children overweight or obese, prevalence having doubled in just a few years, type 2 diabetes, hypertension, dyslipidemia, and fatty livers in children are at their highest levels ever. Half of adults have at least one cardiovascular risk factor. Not even 1% of the population attains ideal cardiovascular health. Despite falling coronary death rates for decades, coronary heart disease (CHD) death rates in US women 35 to 54 years of age may now be increasing because of the obesity epidemic. Up to 65% of patients do not have their conventional risk biomarkers under control. Only 30% of high risk patients with CHD achieve aggressive low density lipoprotein (LDL) targets. Of those patients with multiple risk factors, fewer than 10% have all of them adequately controlled. Even when patients are titrated to evidence-based targets, about 70% of cardiac events remain unaddressed. Undertreatment is also common. About two-thirds of high risk primary care patients are not taking needed medications for dyslipidemia. Poor patient adherence, typically below 50%, adds further difficulty. Hence, after all such fractional reductions are multiplied, only a modest portion of total cardiovascular risk burden is actually being eliminated, and the full potential of risk reduction remains unrealized. Worldwide the situation is similar, with the prevalence of metabolic syndrome approaching 50%. Primordial prevention, resulting from healthful lifestyle habits that do not permit the appearance of risk factors, is the preferred method to lower cardiovascular risk. Lowering the prevalence of obesity is the most urgent matter, and is pleiotropic since it affects blood pressure, lipid profiles, glucose metabolism, inflammation, and atherothrombotic disease progression. Physical activity also improves several risk factors, with the additional potential to lower heart rate. Given the current obstacles, success of primordial prevention remains uncertain. At the same time, the consequences of delay and inaction will inevitably be disastrous, and the sense of urgency mounts. Since most CHD events arise in a large subpopulation of low- to moderate-risk individuals, identifying a high proportion of those who will go on to develop events with accuracy remains unlikely. Without a refinement in risk prediction, the current model of targeting high-risk individuals for aggressive therapy may not succeed alone, especially given the rising burden of risk. Estimating cardiovascular risk over a period of 10 years, using scoring systems such as Framingham or SCORE, continues to enjoy widespread use and is recommended for all adults. Limitations in the former have been of concern, including the under- or over-estimation of risk in specific populations, a relatively short 10-year risk horizon, focus on myocardial infarction and CHD death, and exclusion of family history. Classification errors may occur in up to 37% of individuals, particularly women and the young. Several different scoring systems are discussed in this review. The use of lifetime risk is an important conceptual advance, since ≥90% of young adults with a low 10-year risk have a lifetime risk of ≥39%; over half of all American adults have a low 10-year risk but a high lifetime risk. At age 50 the absence of traditional risk factors is associated with extremely low lifetime risk and significantly greater longevity. Pathological and epidemiological data confirm that atherosclerosis begins in early childhood, and advances seamlessly and inexorably throughout life. Risk factors in childhood are similar to those in adults, and track between stages of life. When indicated, aggressive treatment should begin at the earliest indication, and be continued for years. For those patients at intermediate risk according to global risk scores, C-reactive protein (CRP), coronary artery calcium (CAC), and carotid intima-media thickness (CIMT) are available for further stratification. Using statins for primary prevention is recommended by guidelines, is prevalent, but remains underprescribed. Statin drugs are unrivaled, evidence-based, major weapons to lower cardiovascular risk. Even when low density lipoprotein cholesterol (LDL-C) targets are attained, over half of patients continue to have disease progression and clinical events. This residual risk is of great concern, and multiple sources of remaining risk exist. Though clinical evidence is incomplete, altering or raising the blood high density lipoprotein cholesterol (HDL-C) level continues to be pursued. Of all agents available, rosuvastatin produces the greatest reduction in LDL-C, LDL-P, and improvement in apoA-I/apoB, together with a favorable safety profile. Several recent proposals and methods to lower cardiovascular risk are reviewed. A combination of approaches, such as the addition of lifetime risk, refinement of risk prediction, guideline compliance, novel treatments, improvement in adherence, and primordial prevention, including environmental and social intervention, will be necessary to lower the present high risk burden.

Carotid intima-media thickness as a screening tool in cardiovascular primary prevention

BACKGROUND AND OBJECTIVE

  Increased carotid intima-media thickness (CIMT) is associated with cardiovascular events. The purpose of this study was to identify advanced subclinical atherosclerosis in patients who are at low or intermediate risk.

METHODS

Thousand hundred and eighteen Spanish subjects were prospectively enrolled in an ambulatory screening of cardiovascular risk (CVR). Three hundred and twenty patients aged over 30 years with low-intermediate CVR according to European SCORE function underwent carotid ultrasonography. Carotid IMT and plaque assessment were performed using high-resolution B-mode ultrasonography. Participants with abnormal CIMT were reclassified to high CVR.

RESULTS

According to SCORE function, 104 patients (32·5%) were of low CVR and 216 (67·5%) of intermediate CVR. Mean carotid IMT was 0·62 ± 0·13 mm, and carotid plaque was found in 35 (10·9%) patients. Carotid ultrasonography changed the risk stratum in 59 (18·4%) patients, who were reclassified to high CVR. Reclassification was more frequent in the intermediate CVR group than in the low CVR group (22·7% vs. 9·6%, P = 0·005) and was associated to age (P = 0·002), history of arterial hypertension (P < 0·001) and increased systolic blood pressure (P = 0·05).

CONCLUSIONS

CIMT calculated by high-resolution B-mode ultrasonography could become an important tool in preventive medicine. Measuring CIMT may be useful in identifying asymptomatic individuals with subclinical atherosclerosis not detected by the actual CVR functions.

Role of echocardiographic left ventricular mass and carotid intima-media thickness in the cardiovascular risk assessment of asymptomatic patients with type 2 diabetes mellitus

BACKGROUND

Standard cardiovascular (CV) risk assessment may underestimate risk in people with type 2 diabetes mellitus (T2DM). Cardiac and vascular imaging to detect subclinical disease may augment risk prediction. This study investigated the association between CV risk, left ventricular hypertrophy (LVH) and carotid intima-media thickness (CIMT) in patients with T2DM free of CV symptoms.

METHODS

People with T2DM without known CV disease were recruited from general practice. The 5-year risk of CV events was calculated using an adjusted Framingham equation and the prevalence of LVH and abnormal CIMT across bands of CV risk assessed. In those at intermediate risk, the number needed to scan (NNS) to reclassify one person to high risk was calculated across the group and compared in those above and below 55 years. The association between LV mass and CIMT was also assessed.

RESULTS

Mean age 57 years (SD11), 51% female. Median 5-year CV risk 14.3% (interquartile range 10.3, 19.5), 51% had LVH (American Society of Echocardiography criteria) and 31% an abnormal CIMT (age and sex criteria). In the 52% at intermediate risk, 37% had LVH and 36% an abnormal CIMT. The NNS was 1.7 using both imaging techniques, 2.7 using cardiac imaging alone or 2.8 using vascular imaging alone. Almost twice as many people >55 years had an abnormal CIMT than those <55 years.

CONCLUSIONS

Cardiac and vascular imaging to detect subclinical disease can be used to augment prediction of CV risk in people with T2DM at intermediate risk. The value of reclassifying risk is as yet unproven and requires outcome data from intervention studies.

Common Carotid Artery Intima-media Thickness is not Increased but Distensibility is Reduced in Normotensive Patients with Type 2 Diabetes compared with Control Subjects

This study evaluated carotid artery parameters in normotensive patients with type 2 diabetes compared with non-diabetic control subjects. Using a high-resolution B-mode ultrasound scanner, common carotid artery intima-media thickness (IMT) and carotid tree atheroma thickness were measured in 82 patients with type 2 diabetes and 41 controls. The distensibility of the common carotid artery was calculated using the Reneman equation. Distensibility was significantly decreased and atheroma thickness was significantly increased in the diabetes group. There was no significant difference in IMT between the two groups. Stepwise linear regression analysis revealed an association between common carotid artery distensibility and post-ischaemic dilatation of the brachial artery (a measure of endothelial function), body mass index and diabetes duration in patients with type 2 diabetes. In conclusion, common carotid artery IMT in normotensive patients with type 2 diabetes is comparable to that of control subjects, whereas atheroma thickness is higher and arterial stiffness more pronounced in those with type 2 diabetes, indicating the existence of atherosclerotic changes in normotensive type 2 diabetes patients.

Carotid intima-media thickness: knowledge and application to everyday practice

Heart disease is the primary cause of death in the United States. Fortunately, intervention measures can reduce the risk of cardiovascular disease (CVD) after a patient has been accurately assessed. Atherosclerotic disease, one of the driving forces behind CVD, is not always detected by traditional risk assessment. Carotid intima-media thickness (CIMT), as measured by B-mode ultrasound, is a surrogate marker for atherosclerosis and can be used to detect an accelerated disease process and subclinical disease. Advantages of CIMT are that it is noninvasive, relatively inexpensive, and can be repeatedly performed with no adverse effects on the patient. Carotid intima-media thickness is associated with CVD and is an independent predictor of stroke and myocardial infarction. Therefore, CIMT is valuable for clarifying CVD risk, particularly for patients with intermediate risk by conventional risk assessment. Screening for subclinical disease even in low-risk patients may have benefit, especially for those with a family history of premature CVD or those with any of the National Cholesterol Education Program risk factors. The detection of subclinical atherosclerosis allows the physician to implement prevention efforts prior to a devastating CVD event and to investigate possible reasons for increased arterial thickening, such as an occult underlying insulin-resistant condition or residual lipid risk markers. Treatment with several types of drugs has been demonstrated to halt the progression or even reduce CIMT. Carotid intima-media thickness is currently limited by the lack of standardized protocols that may affect reproducibility from measure to measure. Efforts to draft a standardized protocol are underway by the Society of Atherosclerosis Imaging and Prevention that will address this issue. Carotid intima-media thickness provides a valuable tool for physicians to clarify the CVD risk of their patients. Practical implications of CIMT for everyday clinical practice are addressed.

Association between change in plasma triglyceride levels and risk of stroke and carotid atherosclerosis: systematic review and meta-regression analysis

BACKGROUND AND PURPOSE

The contribution of modifying non-low-density lipoprotein cholesterol (LDL-C) levels to reduce stroke risk remains uncertain. The aim of this study was to investigate the association between treatment-induced change in plasma triglyceride levels and risk of stroke and progression of carotid intima-media thickness (CIMT).

METHODS

We performed a systematic review and meta-regression analyses of randomized controlled trials of lipid-modifying treatments selected from a PubMed search on literature published from 1966 to 2008.

RESULTS

We identified 64 randomized controlled trials (active groups, n=96,807; control groups, n=98,681) that tested lipid-modifying drugs and reported triglyceride levels and stroke outcome. Extracting data from placebo groups, we found a statistically significant association between baseline triglyceride levels and stroke risk (adjusted relative risk [RR], 1.05 per 10-mg/dL increase; 95% CI, 1.03-1.07). Except for a trend in fibrate and niacin trials, there was no evidence of any relationship between degree of triglyceride change and stroke incidence. In multivariable meta-regression analysis including baseline and change in LDL-C, only change in LDL-C was associated with log risk ratio of all strokes (RR reduction, 4.5% per 10-mg/dL reduction; 95% CI, 1.7-7.2; P=.003). Similarly, taking into account 26 randomized controlled trials reporting CIMT outcome, LDL-C reduction was associated with reduced CIMT progression (-3.0 microm/y per 10-mg/dL reduction; 95% CI, -5.5 to -0.4; P=.03).

CONCLUSIONS

In view of the limitations of meta-regression analysis and CIMT measures as surrogate endpoints in lipid-lowering drugs trials, additional studies are needed to more precisely quantify the detrimental effect of triglyceride levels on stroke risk and to establish the efficacy of triglyceride-lowering therapy in addition to LDL-C reduction.

[Carotid intima-media thickness and its current usefulness]

Cardiovascular risk stratification is currently part of routine clinical practice to establish cardiovascular prevention strategies. A complementary approach to the assessment scales of cardiovascular risk stratification is the non-invasive evaluation of the atherosclerotic lesion to identify patients at high risk for cardiovascular complications. Carotid intima-media thickness is a non-invasive method based on ultrasound suitable for the detection of subclinical atherosclerosis. It allows us to stratify cardiovascular risk beyond conventional cardiovascular risk factors and would complement the cardiovascular risk functions. The inclusion of the carotid intima-media thickness in cardiovascular risk stratification may help identify asymptomatic individuals with a high cardiovascular risk not detected by current scales of cardiovascular risk stratification.

Lactation and maternal measures of subclinical cardiovascular disease

OBJECTIVE

To examine the relationship between lactation and subclinical cardiovascular disease in a population free of clinical cardiovascular disease.

METHODS

We conducted a cross-sectional analysis of 297 women who reported at least one live birth on enrollment in the Study of Women Across the Nation-Heart Study. Participants were mothers aged 45-58 years who were free of clinical cardiovascular disease. History of lactation was self-reported. Electron beam tomography was used to assess coronary and aortic calcification. B-mode ultrasonography was used to assess carotid adventitial diameter, intima-media thickness, and carotid plaque. Multivariable linear and logistic regression models were used to estimate whether lactation was independently associated with markers of subclinical cardiovascular disease.

RESULTS

In unadjusted models, compared with mothers who had breastfed all of their children for at least 3 months, mothers who had not breastfed were more likely to have coronary artery calcification (17% compared with 32%), aortic calcification (17% compared with 39%), carotid plaque (10% compared with 18%), and larger carotid adventitial diameters (mean+/-standard deviation 6.63+/-0.59 compared with 6.87+/-0.60 mm). After adjusting for measures of socioeconomic status and lifestyle and family history variables, mothers who had not breastfed remained more likely to have aortic calcification (odds ratio [OR] 3.85, 95% confidence interval [CI] 1.47-10.00) and coronary artery calcification (OR 2.78, 95% CI 1.05-7.14) than mothers who had consistently breastfed. After further adjustment for body mass index and traditional risk factors for cardiovascular disease, mothers who had not breastfed remained more likely to have aortic calcification than mothers who had consistently breastfed (OR 5.26, 95% CI 1.47-20.00).

CONCLUSION

Mothers who do not breastfeed their infants seem to be at increased risk of vascular changes associated with future cardiovascular disease.

LEVEL OF EVIDENCE

II.