Beneficial effects of colestipol-niacin therapy on the common carotid artery. Two- and four-year reduction of intima-media thickness measured by ultrasound

Preclinical carotid atherosclerosis as an indicator of polyvascular disease: a narrative review

Carotid atherosclerotic lesions are correlated with atherosclerotic deterioration of the arterial wall in other vascular territories and with cardiovascular events. The detection of pre-symptomatic carotid lesions like intima-media thickness (IMT) and asymptomatic carotid plaques is possible by non-invasive ultrasound duplex scanning. Current measurement guidelines suggest an average measurement of IMT within 10 mm of the segment of the common carotid artery. The thickening of intima-media appears in a long subclinical period of atherosclerosis. Therefore, the determination of IMT has emerged as one of the methods for determining early structural deterioration of the arterial wall. A close interrelationship was shown between IMT and risk factors of atherosclerosis, their duration, and intensity. Different studies demonstrated that increased IMT is a powerful predictor of coronary, cerebrovascular, and peripheral arterial occlusive disease and their complication. A recent meta-analysis indicated a minimal improvement in the risk estimation of cardiovascular events after adding IMT to the Framingham Risk Score. These findings influenced the latest ACC/AHA guidelines which again recommend the use of carotid IMT measurement for individual risk assessment. The presence of atherosclerotic plaques indicates that the atherosclerotic process is already ongoing. The findings of different studies are equivocal that carotid plaques independently predict cardiovascular events and improve risk predictions for coronary artery disease when added to the Framingham Risk Score. However, besides the size of plaque and grade of stenosis, the structure of plaque calcification, vascularization, lipid core, and the surface of plaques are important indicators of related risks for cardiovascular events.

Traditional Risk Factors are Causally Related to Carotid Intima-Media Thickness Progression: Inferences from Observational Cohort Studies and Interventional Trials

In the present review, associations between traditional vascular risk factors (VRFs) and carotid intimamedial thickness progression (C-IMTp) as well as the effects of therapies for VRFs control on C-IMTp were appraised to infer causality between each VRF and C-IMTp. Cohort studies indicate that smoking, binge drinking, fatness, diabetes, hypertension and hypercholesterolemia are associated with accelerated C-IMTp. An exception is physical activity, with mixed data. Interventions for the control of obesity, diabetes, hypertension and hypercholesterolemia decelerate C-IMTp. Conversely, scarce information is available regarding the effect of smoking cessation, stop of excessive alcohol intake and management of the metabolic syndrome. Altogether, these data support a causative role of several traditional VRFs on C-IMTp. Shortcomings in study design and/or ultrasonographic protocols may account for most negative studies, which underlines the importance of careful consideration of methodological aspects in investigations using C-IMTp as the outcome.

Carotid Intima-Media Thickness Progression as Surrogate Marker for Cardiovascular Risk: Meta-Analysis of 119 Clinical Trials Involving 100 667 Patients

BACKGROUND

To quantify the association between effects of interventions on carotid intima-media thickness (cIMT) progression and their effects on cardiovascular disease (CVD) risk.

METHODS

We systematically collated data from randomized, controlled trials. cIMT was assessed as the mean value at the common-carotid-artery; if unavailable, the maximum value at the common-carotid-artery or other cIMT measures were used. The primary outcome was a combined CVD end point defined as myocardial infarction, stroke, revascularization procedures, or fatal CVD. We estimated intervention effects on cIMT progression and incident CVD for each trial, before relating the 2 using a Bayesian meta-regression approach.

RESULTS

We analyzed data of 119 randomized, controlled trials involving 100 667 patients (mean age 62 years, 42% female). Over an average follow-up of 3.7 years, 12 038 patients developed the combined CVD end point. Across all interventions, each 10 μm/y reduction of cIMT progression resulted in a relative risk for CVD of 0.91 (95% Credible Interval, 0.87-0.94), with an additional relative risk for CVD of 0.92 (0.87-0.97) being achieved independent of cIMT progression. Taken together, we estimated that interventions reducing cIMT progression by 10, 20, 30, or 40 μm/y would yield relative risks of 0.84 (0.75-0.93), 0.76 (0.67-0.85), 0.69 (0.59-0.79), or 0.63 (0.52-0.74), respectively. Results were similar when grouping trials by type of intervention, time of conduct, time to ultrasound follow-up, availability of individual-participant data, primary versus secondary prevention trials, type of cIMT measurement, and proportion of female patients.

CONCLUSIONS

The extent of intervention effects on cIMT progression predicted the degree of CVD risk reduction. This provides a missing link supporting the usefulness of cIMT progression as a surrogate marker for CVD risk in clinical trials.

Synthesis, Docking, Computational Studies, and Antimicrobial Evaluations of New Dipeptide Derivatives Based on Nicotinoylglycylglycine Hydrazide

Within a series of dipeptide derivatives (5–11), compound 4 was refluxed with d-glucose, d-xylose, acetylacetone, diethylmalonate, carbon disulfide, ethyl cyanoacetate, and ethyl acetoacetate which yielded 5–11, respectively. The candidates 5–11 were characterized and their biological activities were evaluated where they showed different anti-microbial inhibitory activities based on the type of pathogenic microorganisms. Moreover, to understand modes of binding, molecular docking was used of Nicotinoylglycine derivatives with the active site of the penicillin-binding protein 3 (PBP3) and sterol 14-alpha demethylase’s (CYP51), and the results, which were achieved via covalent and non-covalent docking, were harmonized with the biological activity results. Therefore, it was extrapolated that compounds 4, 7, 8, 9, and 10 had good potential to inhibit sterol 14-alpha demethylase and penicillin-binding protein 3; consequently, these compounds are possibly suitable for the development of a novel antibacterial and antifungal therapeutic drug. In addition, in silico properties of absorption, distribution, metabolism, and excretion (ADME) indicated drug likeness with low to very low oral absorption in most compounds, and undefined blood–brain barrier permeability in all compounds. Furthermore, toxicity (TOPKAT) prediction showed probability values for all carcinogenicity models were medium to pretty low for all compounds.

Periodontal therapy and cardiovascular risk

Cardiovascular diseases are the worldwide leading cause of mortality. Cardiovascular diseases are noncommunicable conditions with a complex pathogenesis, and their clinical manifestations include major cardiovascular events such as myocardial infarction and stroke. Epidemiologic evidence suggests a consistent association between periodontitis and increased risk of cardiovascular diseases. Some evidence supports a beneficial effect of the treatment of periodontitis on both surrogate and hard cardiovascular outcomes. This narrative review has been conducted as an update of the most recent evidence on the effects of periodontitis treatment on cardiovascular outcomes since the last commissioned review of the European Federation of Periodontology-American Academy of Periodontology World Workshop in 2012. Newer evidence originating from published randomized controlled trials confirms a positive effect of periodontal treatment on surrogate measures of cardiovascular diseases, whereas there have been no randomized controlled trials investigating the effect of periodontal treatment on the incidence of cardiovascular disease events such as myocardial infarction and stroke. In conclusion, there is sufficient evidence from observational and experimental studies on surrogate cardiovascular measures to justify the design and conduct of appropriately powered randomized controlled trials investigating the effect of effective periodontal interventions on cardiovascular disease outcomes (ie, myocardial infarction and stroke) with adequate control of traditional cardiovascular risk factors.

APOL1 Genetic Variants Are Associated with Serum-Oxidized Low-Density Lipoprotein Levels and Subclinical Atherosclerosis in South African CKD Patients

INTRODUCTION

Apolipoprotein L1 (APOL1) plays an important role in cholesterol metabolism and attenuation of low-density lipoprotein (LDL) oxidation. While protecting against Trypanosoma brucei rhodesiense infection, APOL1 risk alleles confer greater risk for CKD and cardiovascular disease among patients of African descent.

OBJECTIVES

We investigated whether APOL1 risk variants are associated with atherosclerosis and oxidized LDL (OxLDL) levels among black South African CKD patients.

METHODS

A cross-sectional study of 120 adult CKD patients and 40 controls was undertaken. DNA samples of participants were genotyped for APOL1 G1 and G2 variants. High-sensitivity C-reactive protein, serum lipids, and OxLDL levels were measured, and carotid doppler ultrasonography was performed on all participants.

RESULTS

APOL1 alleles rs73885319, rs60910145, and rs71785313 had minor allele frequencies of 9.2, 8.8, and 17.5%, respectively, in the patients, and 8.8, 8.8, and 13.8%, respectively, in the controls. Of the 9 patients with 2 APOL1 risk alleles, 77.8% were compound G1/G2 heterozygotes and 22.2% were G2 homozygotes. Carriers of at least 1 APOL1 risk allele had a 3-fold increased risk of subclinical atherosclerosis (odds ratio 3.19; 95% confidence interval: 1.64-6.19; p = 0.01) compared to individuals with no risk alleles. Patients with 1 or 2 APOL1 risk alleles showed a significant increase in OxLDL levels when compared with those without the APOL1 risk allele.

CONCLUSION

These findings suggest an increased risk for atherosclerosis in carriers of a single APOL1 risk variant, and the presence of APOL1 risk variants was associated with increased serum OxLDL levels in black South African CKD patients.

Lifestyle Interventions and Carotid Plaque Burden: A Comparative Analysis of Two Lifestyle Intervention Programs in Patients with Coronary Artery Disease

BACKGROUND

The cardioprotective effects of intensive lifestyle regimens in primary prevention have been elucidated; however, there is a paucity of data comparing the effects of different lifestyle regimens in patients with established coronary artery disease (CAD) or CAD equivalent, specifically vis-à-vis carotid plaque regression.

METHODS

We performed a randomized, single-center, single-blind study in 120 patients with established CAD. Patients were randomly assigned to either 9 months of the Complete Health Improvement Program (CHIP), an outpatient lifestyle enrichment program that focuses on improving dietary choices, enhancing daily exercise, increasing support systems, and decreasing stress; or to 9 months of an ad hoc, nonsequential combination of various healthy living classes offered separately through a health maintenance organization and referred to as the Healthy Heart program. Baseline and 9-month change in carotid intima-media thickness (CIMT) were measured.

RESULTS

Among 120 participants, data were analyzed for 79, of which 68 (86%) completed the study. Both average CIMT and average maximum CIMT increased over 9 months, but the changes between groups were insignificant. There were marked differences in the mean body mass index favoring the CHIP group (-1.9 [standard deviation = 1.9]; p < 0.001) and statistically significant within-group improvements in blood pressure, triglyceride level, 6-minute walk test result, self-assessment well-being score, and Patient Health Questionnaire-9 score that were not observed between groups.

CONCLUSION

Neither the CHIP nor Healthy Heart was effective in inducing plaque regression in patients with established CAD after a 9-month period. However, both were effective in improving several CAD risk factors, which shows that the nonsequential offering of healthy lifestyle programs can lead to similar outcomes as a formal, sequential, established program (CHIP) in many aspects. These results have important implications as to how lifestyle changes will be implemented as tertiary prevention measures in the future.

Comparison of Chronic Hemodialysis Patients under Strict Volume Control with respect to Cardiovascular Disease

BACKGROUND

The objective of this study was to determine the effects of strict volume control and nondipper situation on cardiovascular disease in chronic hemodialysis patients.

METHODS

This study is an observational and cross-sectional study including 62 patients with normotensive chronic hemodialysis using no antihypertensive drugs. A series of measurements including ambulatory blood pressure monitoring, left ventricular mass index by echocardiography, common carotid artery intima-media thickness by ultrasound, and body fluids by bioimpedance analysis were conducted for all subjects.

RESULTS

The patients were divided into two groups as dippers and nondippers according to their ambulatory blood pressure monitoring results. Average 48 h systolic, diastolic, and mean arterial blood pressure and nocturnal systolic, diastolic, and mean arterial blood pressure were significantly different between the dipper and nondipper groups (p<0.05). Before and after dialysis, extracellular fluid/intracellular fluid and extracellular fluid/dry body weight ratios were significantly higher in the nondipper group. Left ventricle mass index and interventricular septum thickness were significantly higher in the nondipper group (p<0.05). Left ventricle ejection fraction was significantly lower and common carotid artery intima-media thickness was higher in the nondipper group with a statistical significance (p<0.05). A two-predictor logistic model was fitted to the data to predict the comparability of dippers and nondippers.

CONCLUSION

According to logistic regression analysis, the odds ratio for daytime diastolic blood pressure indicates that nondippers are 0.45 times more likely to have high blood pressure than dippers in daytime. But in night time, nondippers are about 2.55 times more likely to have high blood pressure comparing to dippers. An important finding of this study is that nondipping pattern is associated with cardiac hypertrophy and lower left ventricle ejection fraction in dialysis of patients with no hypertension. The results also suggest that applying strict volume control to achieve a normal blood pressure alone is not sufficient to reduce the risk of cardiovascular morbidity and mortality if the patients do not have a dipper status of nocturnal blood pressure.

Carotid Intima-Media Thickness as a Cardiovascular Risk Factor and Imaging Pathway of Atherosclerosis

Assessment of carotid intima-media thickness (IMT) has emerged as a simple and noninvasive technique for measuring atherosclerotic burden. Although serum biomarkers have been linked to the risk of developing atherosclerosis, carotid IMT has the theoretical advantage of directly visualizing a final consequence of the disease itself, namely atherosclerosis in the vessel wall. The current widespread application of carotid IMT measurements has been based on the validity, standardization, and reproducibility of the measurement and the evidence that an increased carotid IMT can be regarded as an attractive biomarker of atherosclerosis and of increased cardiovascular risk, potentially useful as a therapeutic target in those at increased cardiovascular risk. The utilization of carotid IMT measurements as a surrogate end point in clinical trials evaluating a specific drug intervention may result in considerably smaller efforts and costs than when using a hard end point such as myocardial infarction, stroke, or death. In addition, the use of carotid IMT measurement as a screening tool in clinical practice in association with traditional risk factors may improve risk classification and decisions regarding therapeutic interventions. However, although carotid IMT may be correlated with clinical outcomes, changes in surrogate end points over time that result from a particular therapy may not necessarily be predictive of future cardiovascular events. Therefore, it is necessary to perform more clinical studies to clearly define the relationship between the modifications in carotid IMT and the changes in cardiovascular events. In an era of economic burden, when there is a clear combination of limited resources with high expense of innovation in drug development, carotid IMT represents a reasonable, worthwhile surrogate trial end point with a history of nearly 30 years of technical progress and clinical research. Current data strongly suggest that carotid IMT will continue to successfully be used as a valuable tool in clinical atherosclerosis research.

Apolipoproteins A-I, B, and C-III and Obesity in Young Adult Cherokee

Since young adult Cherokee are at increased risk for both diabetes and cardiovascular disease, we assessed association of apolipoproteins (A-I, B, and C-III in non-HDL and HDL) with obesity and related risk factors. Obese participants (BMI ≥ 30) aged 20–40 years (n = 476) were studied. Metabolically healthy obese (MHO) individuals were defined as not having any of four components of the ATP-III metabolic syndrome after exclusion of waist circumference, and obese participants not being MHO were defined as metabolically abnormal obese (MAO). Associations were evaluated by correlation and regression modeling. Obesity measures, blood pressure, insulin resistance, lipids, and apolipoproteins were significantly different between groups except for total cholesterol, LDL-C, and HDL-apoC-III. Apolipoproteins were not correlated with obesity measures with the exception of apoA-I with waist and the waist : height ratio. In a logistic regression model apoA-I and the apoB : apoA-I ratio were significantly selected for identifying those being MHO, and the result (C-statistic = 0.902) indicated that apoA-I and the apoB : apoA-I ratio can be used to identify a subgroup of obese individuals with a significantly less atherogenic lipid and apolipoprotein profile, particularly in obese Cherokee men in whom MHO is more likely.

Cell-Based Models for Development of Antiatherosclerotic Therapies

The leading cause of death worldwide is cardiovascular disease. Among the conditions related to the term, the most prominent one is the development of atherosclerotic plaques in the walls of arteries. The situation gets even worse with the fact that the plaque development may stay asymptomatic for a prolonged period of time. When it manifests as a cardiovascular disorder, it is already too late: the unfortunate individual is prescribed with a plethora of synthetic drugs, which are of debatable efficacy in the prevention of atherosclerotic lesions and safety. Cell models could be useful for the purpose of screening substances potentially effective against atherosclerosis progression and effective in reduction of already present plaques. In this overview, we present studies making use of in vitro and ex vivo models of atherosclerosis development that can prove valuable for clinical applications.

Association between HbA1c and carotid atherosclerosis among elderly Koreans with normal fasting glucose

Aim

We examined whether glycated haemoglobin (HbA1c) is associated to carotid atherosclerosis in an elderly Korean population with normal fasting glucose.

Methods

Using data from the Korean Urban Rural Elderly study, we conducted a cross-sectional analysis of 1,133 participants (335 men and 798 women) with a mean age of 71.8 years. All participants had fasting blood glucose less than 100mg/dL (5.6 mmol/L) and HbA1c level below 6.5% (48 mmol/mol). They were also free from a history of cardiovascular disease, known type 2 diabetes mellitus or use of anti-diabetes medications. Carotid atherosclerosis was assessed by intima-media thickness (IMT) using ultrasonography. The association between HbA1c and carotid IMT was investigated using multivariable linear regression analysis.

Results

HbA1c levels were independently and positively associated with carotid IMT (β = 0.020, p = 0.045) after adjusting for sex, age, body mass index, systolic blood pressure, diastolic blood pressure, triglyceride, LDL cholesterol, smoking and alcohol intake. However, fasting insulin and glucose levels were not associated with carotid IMT.

Conclusion

HbA1c levels were positively associated with carotid atherosclerosis, as assessed by carotid IMT, in an elderly population with normoglycemia. Our study suggested that higher HbA1c level is an effective and informative marker of carotid atherosclerosis in an elderly population.

Intima-media thickness: indicator of cardiovascular risk and measure of the extent of atherosclerosis

The measurement of intima-media thickness (IMT) of large superficial arteries, especially the carotid, using high-resolution B-mode ultrasonography has emerged as one of the methods of choice for determining the anatomic extent of atherosclerosis and for assessing cardiovascular risk. IMT measurement obtained by ultrasonography correlates very well with pathohistologic measurements and the reproducibility of this technique is good. Population studies have shown a strong correlation between carotid IMT and several cardiovascular risk factors, and it has also been found to be associated with the extent of atherosclerosis and end-organ damage of high-risk patients. Therefore, increased carotid IMT is a measure of athero-sclerotic burden and a predictor of subsequent events. Because of its quantitative value, carotid IMT measurement is more and more frequently used in clinical trials to test the effects of different preventive measures, including drugs. More recently, there has been interest in the clinical use of this technique for detecting preclinical (asymptomatic) atherosclerosis and for identifying subjects at high risk. Measurement of carotid IMT could influence a clinician to intervene with medication and to use more aggressive treatment of risk factors in primary prevention, and in patients with atherosclerotic disease in whom there is evidence of progression and extension of atherosclerotic disease. For more extensive use of this method in clinical practice a consensus concerning the standardization of methods of measurement and precise definition of threshold between normal and pathologic IMT value is urgently needed.

Management of extracranial carotid artery disease

Stroke is the third leading cause of death in developed nations. Up to 88% of strokes are ischemic in nature. Extracranial carotid artery atherosclerotic disease is the third leading cause of ischemic stroke in the general population and the second most common nontraumatic cause among adults younger than 45 years. This article provides comprehensive, evidence-based recommendations for the management of extracranial atherosclerotic disease, including imaging for screening and diagnosis, medical management, and interventional management.

Extended-release niacin/lovastatin: the first combination product for dyslipidemia

Many clinical studies have demonstrated that lipid-altering drug treatments, including the use of statin and niacin monotherapy, can be effective in the primary and secondary prevention of coronary heart disease, but only in a minority of patients relative to placebo. Since statins and niacin have entirely different mechanisms of action and predominantly different effects on blood lipid levels, the combined use of both a statin and niacin may confer complementary benefits on multiple lipid parameters, produce a more global improvement in lipid blood levels and result in greater reductions in coronary heart disease risk factors than the administration of either agent alone. This may be of particular importance in patients with complex dyslipidemias, such as those with Type 2 diabetes mellitus and metabolic syndrome. This review summarizes the efficacy and safety of extended-release niacin/lovastatin (Advicor, Kos Pharmaceuticals Inc.), the first combination product approved for the management of dyslipidemia.

Determination of site-specific carotid-intima media thickness: common -carotid artery and carotid bifurcation in hypercholesterolemia patients

Objective: To determine site specific carotid intima-media thickness: common–carotid artery and carotid bifurcation in hypercholesterolemia patients as a marker for atherosclerosis.

Methods: Fifty patients with hypercholesterolemia and twenty controls were selected after getting informed consent regarding the investigation of carotid- intima media thickness by B-mode ultrasound. All the patients of hypercholesterolemia with LDL-C > 160mg/dL had family history of coronary artery diseases. This procedure was carried out in the Radiology Department of Dr. Ziauddin Hospitals. Measurement of carotid -intima media thickness, B-mode ultrasonography of common carotid artery, carotid bifurcation and internal carotid artery (left and right carotid arteries) was performed with Toshiba (M# SSA-580A/E2) ultrasound scanner with linear probe. The posterior or far wall of the carotid artery is, the distance between the leading edge first bright line (lumen -intima interface) and the leading edge of the second bright line (media-adventitia interface) of far wall was recorded as intima -media thickness. The average mean of six segments of intima-media thickness was taken as mean CIMT of right and left common carotid, bifurcation and internal carotid arteries.

Results: Maximal CIMT was significantly increased at sites common carotid, carotid bifurcation and internal carotid arteries in fifty patients with hypercholesterolemia as compared to controls. At carotid bifurcation mean of maximal CIMT was (0.9+ 0.3mm). Range of maximum CIMT in hypercholesterolemia patients was (0.8- 3.3mm) and in controls (0.4- 0.8 mm). The thickness was more frequently increased at site of bifurcation.

Conclusions: Carotid intima- media thickness in hypercholesterolemia patients was increased and carotid bifurcation was site that has shown greater increase in intima-media thickness and plaques in these patients predict high risk for atherosclerosis.

Carotid intima-media thickness testing as an asymptomatic cardiovascular disease identifier and method for making therapeutic decisions

Cardiovascular disease (CVD) is the leading cause of death and disability in the United States. Although current therapies can reduce the risk for CVD, they are only given to patients who are considered to be at risk, and are therefore only beneficial if a patient's risk is accurately predicted before he or she sustains a cardiovascular (CV) event. Unfortunately, even relatively accurate risk factor analyses, such as the Reynolds Risk Score algorithm, fail to identify some patients who will sustain a CV event within 10 years. In contrast, the presence of an atheroma is an absolute predictor for the potential of an atherothrombotic event to occur, and it is therefore reasonable to anchor clinical decisions based on this knowledge. Carotid intima-media thickness (CIMT) testing via B-mode ultrasound is a safe, simple, and inexpensive method for evaluating CV risk by measuring the combined thickness of the intimal and medial layers of the arterial wall. Use of CIMT testing can also detect marked thickening of the arterial wall, possibly indicating plaques or atheromas that are associated with accelerated atherosclerotic disease and increased risk for coronary artery disease, myocardial infarction, and stroke. These characteristics make CIMT a practical supplemental method that physicians can use when making decisions. Moreover, the ability of CIMT testing to identify and quantify atherosclerotic disease has led to the adoption of CIMT as a surrogate endpoint in clinical trials, allowing the efficacy of new drugs to be assessed much more rapidly than would be possible by focusing solely on CV event or mortality rates. To date, several trials have provided evidence to indicate that some CVD therapies slow, stop, or reverse the progression of CIMT. Although many of these studies show that changes in CIMT predict future CV events, the value of CIMT testing in CVD risk assessment is still vigorously debated. In this article, we clarify the utility of CIMT testing for risk classification and reexamine its usefulness as a method for assessing therapeutic efficacy.

HDL cholesterol and cardiovascular outcomes: what is the evidence?

The relationship between low concentrations of high density lipoprotein cholesterol (HDL-C) and heightened risk for cardiovascular (CV) disease has been known for decades. Despite the consistent inverse relationship among epidemiological studies, the linkage between a residual low HDL-C among patients treated with statins and excess cardiovascular risk is less clearly established. Encouraging results from trials using niacin over the past 40 years have not been validated among more recent trials in patients taking contemporary anti-atherosclerotic therapy. Emerging evidence suggests that certain subsets of HDL particles may be more protective and/or more closely associated with CV disease than others, which may impact therapeutic benefits. Ongoing clinical trials will clarify whether raising HDL-C per se directly translates into a reduction in hard CV events. Until those results are available, the clinician is left with only weak evidence to support whether or not to target treatment of HDL-C with pharmacological therapy.

Use of carotid intima-media thickness regression to guide therapy and management of cardiac risks

OPINION STATEMENT

Although carotid intima-media thickness (IMT) has been broadly used as a tool to evaluate cardiovascular risk, its role as a surrogate endpoint is still debated. The main issue is the fact that no study has ever been powered to show a relationship between changes in carotid IMT during follow-up and cardiovascular events. A meta-analysis of existing clinical studies was performed to investigate this relationship but it failed to demonstrate a predictive role of regression in carotid IMT for cardiovascular events. The reasons for the lack of a clear evidence for a predictive role of IMT progression are unknown but are likely multifactorial. Firstly, it may depend on the fact that this index is not a pure atherosclerosis index. Second, carotid atherosclerosis does not always reflect coronary atherosclerosis. Furthermore, methodologic problems related to intra- and interobserver variability make this index not adequately reproducible when tracking the progression of carotid atherosclerosis. A further meta-analysis based on individual patient data, instead of published data, has been planned to better address the predictive role of IMT. Lastly, in the future, the variability of ultrasound measurements of carotid IMT are likely to be reduced by further development of automatic calculation of this index by magnetic resonance imaging.

The measurement of lipids currently and 9 years ago--which is more associated with carotid intima-media thickness?

BACKGROUND

Massive evidence supports that increase of lipids bring more risk of atherosclerosis. However, it is not clear if lipids measured a long time ago bear more risk than the current measurement.

HYPOTHESIS

Lipids measured currently is more associated with carotid atherosclerosis than lipids measured long time ago.

METHODS

A cohort of 1195 participants age 35 to 64 years was examined in both 1993-1994 and 2002 for serum lipids, and in 2002 for carotid intima-media thickness (CIMT) with B mode ultrasound. The associations of lipids at baseline and at reexamination with CIMT were analyzed and compared using multiple linear regressions.

RESULTS

All lipid variables, except for high-density lipoprotein cholesterol (HDL-C) both at baseline and reexamination, were significantly associated with age-adjusted CIMT in both males and females (all P(trend) <0.01). The age-adjusted mean of CIMT in all of the population was 0.696 mm in those having low low-density lipoprotein cholesterol (LDL-C) at both examinations, 0.719 mm in those having high LDL-C only at baseline, 0.706 mm in those having high LDL-C only at reexamination, and 0.727 mm in those having high LDL-C at both examinations. Further analysis showed that lipids measured at baseline remained significant, whereas lipids at reexamination became not significant in all models, except those for HDL-C and total cholesterol (TC)/HDL-C, which allow the lipids at different times to compete in association with CIMT.

CONCLUSIONS

Both the current measurement of lipids (TC, LDL-C, non-HDL-C, TC/HDL-C, and LDL-C/HDL-C) and the measurement from 9 years ago are significantly associated with CIMT, but the measurement from 9 years ago had an even stronger association.

Significance of the intima-media thickness of carotid and thoracic aorta in coronary artery disease in the South Indian population

Background:

Ultrasound detected intima-media thickness (IMT) of the carotid artery and thoracic aorta are possible screening tests to assess the risk of coronary artery disease (CAD) in asymptomatic individuals.

Objective:

Aim of the study was to assess the utility of carotid and aortic IMT as a predictor of CAD and to assess the extent of IMT with severity of CAD in a South Indian population.

Patients and Methods:

A cross-sectional and analytical study was carried out among 40 cases, who had angiographic evidence of CAD against 30 healthy control subjects with a normal treadmill test. At plaque-free regions, the carotid IMT was evaluated by B-mode ultrasonography and thoracic aorta IMT was evaluated by trans-esophageal echocardiography (TEE). The significance of difference in means between two groups was analyzed using one-way ANOVA F-test and the significance of difference in proportions by Chi-square test. Multiple comparisons were done by Bonferroni t test. The correlation between IMT and severity of CAD was assessed by Spearman's method.

Results:

There were 38 males and 2 females among cases with age 51.7 ± 8.3 years, and 28 males and 2 females among control subjects with age 52.2 ± 7.1 years. Increased carotid IMT was noted among 24 cases and 2 control subjects, and the association was significant for CAD [P < 0.001, Chi-square = 20.89, odds ratio (OR) = 21.00, and 95% confidence interval (CI) = 4.78-89.59]. Similarly, 19 cases and one control subject had abnormal IMT with positive correlation for CAD (P < 0.001, Chi-square = 16.39, OR = 28.24, and 95% CI = 4.06-163.21). There was no association between IMT and diabetes, hypertension, or smoking; however, IMT was significantly associated with age and dyslipidemia. Also, there was no correlation between extent of IMT and severity of CAD.

Conclusions:

IMT of the carotid and thoracic aorta is strongly associated with risk of CAD in a South Indian population, and may be used as a non-invasive screening tool for coronary atherosclerosis in resource-limited settings. The presence of dyslipidemia influenced IMT and may be used as a tool to follow patients on hypolipidemic drugs.

Questioning the predictive role of carotid intima-media thickness

Interest in carotid intima-media thickness (IMT), as a tool to evaluate cardiovascular risk has been driven by studies that demonstrate a relationship between carotid IMT and the incidence of cardiovascular events. However, no study was designed and powered to demonstrate a relationship between changes in carotid IMT during follow-up and cardiovascular events. Therefore, a pooled analysis of existing clinical studies was performed to investigate this relationship. This analysis failed to demonstrate a predictive role of changes in carotid IMT for cardiovascular events. The reason for the lack of clear evidence for a predictive role for changes in IMT are uncertain but may reflect methodological problems related to intra- and inter-observer variability, as it seems unlikely that progression of carotid atherosclerosis would not predict outcome. A further meta-analysis based on individual patient-data has been planned, that may better address this issue. The variability of ultrasound measurements of carotid IMT are likely to be reduced by further development of automatic calculation of this index by MRI.

Utility of atherosclerosis imaging in the evaluation of high-density lipoprotein-raising therapies

Decreased level of high density-lipoprotein cholesterol (HDL-C) is a rigorous predictor for future cardiovascular events. Much effort is being made to develop HDL-C–raising pharmacotherapies in the attempt to avert the pandemic of atherosclerotic disease. Important properties by which HDL-C–raising compounds are effective involve improvement of cholesterol uptake from macrophages in plaque for transport back to the liver, improvement of endothelial function, and anti-inflammatory effects. Vascular imaging can aid in the determination which HDL-C–raising compounds are effective. Ultrasound and MRI have proved suitable for assessment of structural changes of the vessel wall. Ultrasound can also be used or assessment of endothelial function. 18F-fluordeoxyglucose positron emission tomography has opened up the possibility to assess vessel wall inflammation. In this article we discuss these various imaging techniques and how they can assess efficacy as well as provide pathophysiologic information on the mechanism of action of novel HDL-C–raising drugs.

Niacin extended-release therapy in phase III clinical trials is associated with relatively low rates of drug discontinuation due to flushing and treatment-related adverse events: a pooled analysis

BACKGROUND AND OBJECTIVE

Niacin is a highly effective agent for increasing low high-density lipoprotein cholesterol (HDL-C) levels. It also has beneficial effects on key pro-atherogenic lipoprotein parameters. However, the side effect of flushing can challenge patient adherence to treatment. In this study, we pooled safety data from available trials of at least 16 weeks' duration to evaluate the impact of flushing on patient adherence to niacin extended-release (NER) therapy.

METHODS

Data were pooled from eight NER studies (administered as NER with a maximum dosage of 1000, 1500, and 2000 mg/day, either as monotherapy or in combination with simvastatin 20 or 40 mg/day [NER/S], or lovastatin 20 or 40 mg/day [NER/L]) to evaluate rates of study discontinuation due to flushing or any treatment-related adverse events.

RESULTS

While 66.6% of patients experienced flushing, only 5.2% of patients discontinued treatment due to flushing. Of the total number of patients treated with NER (n = 307), NER/S (n = 912), or NER/L (n = 928), 34 (11%), 105 (11%), and 127 (14%) patients discontinued due to any treatment-related adverse event, respectively, while 14 (5%), 43 (5%), and 55 (6%) discontinued due to flushing. Discontinuation for flushing did not differ with regard to maximum dose, or to the presence or type of statin combined with NER.

CONCLUSION

Although flushing was common with NER treatment, discontinuation due to flushing occurred in only 5-6% of patients in this pooled analysis. This could be due to several factors, including the fact that all patients in the NER trials were educated about flushing and its management. Translation of methodology employed in these trials into clinical practice may improve long-term adherence to NER therapy, which would enhance the therapeutic benefit of NER for reducing cardiovascular risk.

Opening a new lipid "apo-thecary": incorporating apolipoproteins as potential risk factors and treatment targets to reduce cardiovascular risk

Statins (3-hydroxy-3-methylglutaryl-coenzyme A reductase inhibitors) represent the cornerstone of drug therapy to reduce low-density lipoprotein (LDL) cholesterol and cardiovascular risk. However, even optimal statin management of LDL cholesterol leaves many patients with residual cardiovascular risk, in part because statins are more effective in reducing LDL cholesterol than apolipoprotein B (Apo B). Apo B may be a better marker of atherogenic risk than LDL cholesterol because Apo B measures the total number of all atherogenic particles (total atherosclerotic burden), including LDL, very low-density lipoprotein, intermediate-density lipoprotein, remnant lipoproteins, and lipoprotein(a). To determine whether Apo B is a better indicator of baseline cardiovascular risk and residual risk after lipid therapy compared with LDL cholesterol, a MEDLINE search of the literature published in English from January 1, 1975, through December 1, 2010, was conducted. On the basis of data from most population studies, elevated Apo B was more strongly associated with incident coronary heart disease than similarly elevated LDL cholesterol. Apo B was also a superior benchmark (vs LDL cholesterol) of statins' cardioprotective efficacy in both primary-prevention and secondary-prevention trials. To minimize cardiovascular risk among persons with hypercholesterolemia or dyslipidemia, the best available evidence suggests that intensive therapy with statins should be initiated to achieve the lowest possible Apo B level (with adequate drug toleration) and then other therapies (eg, niacin, bile acid resins, ezetimibe) added to potentiate these Apo B-lowering effects. In future consensus lipid-lowering treatment guidelines, Apo B should be considered as an index of residual risk, a potential parameter of treatment efficacy, and a treatment target to minimize risk of coronary heart disease.

Endothelial arginase II and atherosclerosis

Atherosclerotic vascular disease is the leading cause of morbidity and mortality in developed countries. While it is a complex condition resulting from numerous genetic and environmental factors, it is well recognized that oxidized low-density lipoprotein produces pro-atherogenic effects in endothelial cells (ECs) by inducing the expression of adhesion molecules, stimulating EC apoptosis, inducing superoxide anion formation and impairing protective endothelial nitric oxide (NO) formation. Emerging evidence suggests that the enzyme arginase reciprocally regulates NO synthase and NO production by competing for the common substrate L-arginine. As oxidized LDL (OxLDL) results in arginase activation/upregulation, it appears to be an important contributor to endothelial dysfunction by a mechanism that involves substrate limitation for endothelial NO synthase (eNOS) and NO synthesis. Additionally, arginase enhances production of reactive oxygen species by eNOS. Arginase inhibition in hypercholesterolemic (ApoE^-/-) mice or arginase II deletion (ArgII^-/-) mice restores endothelial vasorelaxant function, reduces vascular stiffness and markedly reduces atherosclerotic plaque burden. Furthermore, arginase activation contributes to vascular changes including polyamine-dependent vascular smooth muscle cell proliferation and collagen synthesis. Collectively, arginase may play a key role in the prevention and treatment of atherosclerotic vascular disease.

New evidence for nicotinic acid treatment to reduce atherosclerosis

Nicotinic acid (at a daily dose of grams) has been shown to induce potent anti-atherosclerotic effects in human and animal models. Evidence from clinical studies performed in the 1950s has shown that nicotinic acid treatment remarkably improves the plasma lipid profile. Large clinical studies showed that nicotinic acid improves clinical cardiovascular outcomes. Given the protective effects of niacin, basic research studies were designed to explore additional anti-atherosclerotic pathways, such as those involved in cardiovascular inflammation. After the discovery of the nicotinic acid receptor GPR109A on adipocytes and immune cells, novel direct immunomodulatory properties of nicotinic acid have been identified. Importantly, the regulation of the release of inflammatory mediators from adipose tissue was observed, independent of lipid level amelioration. Less is known about the possible direct anti-inflammatory activities of nicotinic acid in other cells (such as hepatocytes, endothelial and vascular cells) previously indicated as key players in atherogenesis. Thus, further studies are needed to clarify this promising topic. Emerging evidence from clinical and basic research studies indicates that novel direct anti-atherosclerotic properties might mediate nicotinic acid-induced cardiovascular protection. Despite some limitations in its clinical use (mainly due to the incidence of adverse events, such as cutaneous flushing and hepatotoxicity), nicotinic acid should be considered as a very potent therapeutic approach to reduce atherosclerosis. Promising research developments are warranted in the near future.

Effectiveness of pentoxifylline on the cross-sectional area of intima media thickness and functions of the common carotid artery in adolescents with type 1 diabetes

OBJECTIVE

The aim of the present study was to evaluate the effect of oral pentoxifylline on the cross-sectional area of intima media thickness (CSA-IMT) and functions of the common carotid artery, a marker of early atherosclerosis, in adolescents with type 1 diabetes.

PATIENTS AND METHODS

Non-invasive ultrasonographic measurements were made in 56 type 1 diabetic patients. The diabetic patients were matched first in terms of age, diabetes duration, major cardiovascular risk factors, including anthropometric and metabolic parameters as well as ultrasonographic measurements, then one individual within each pair randomized into a pentoxifylline group and a placebo (control) group (i.e., 32 on pentoxifylline group and 24 on placebo). Pentoxifylline was administered for 6 months. We investigated the change of CSA-IMT, compliance, distensibility, diastolic wall stress (DWS), and incremental elastic modulus of the common carotid artery at 6 months after pentoxifylline.

RESULTS

In comparison of changes in common carotid artery measurements between the two groups, the pentoxifylline treatment group had significantly higher values than the controls for CSA-IMT (-2.6 +/- 0.1 vs. 0.7 +/- 0.4 mm2, p = 0.001) and for DWS (-0.38 +/- 0.02 vs. -0.05 +/- 0.05 mm Hg x 10(2), p < 0.001). In a multivariate regression model for all patients, being in pentoxifylline group was the best predictor of the change DWS (beta = -0.52, p < 0.001).

CONCLUSION

Our preliminary results suggest that pentoxifylline has an antiatherogenic action and might modulate risk factors for atherosclerosis in type 1 diabetes.

Strategies to reverse atherosclerosis: an imaging perspective

Several treatment strategies, including lowering low-density lipoprotein cholesterol with intensive statin therapy, reducing triglycerides with fibrates, and raising high-density lipoprotein cholesterol with nicotinic acid, have the potential to induce atherosclerosis regression. Atherosclerosis imaging techniques including intravascular ultrasound, carotid ultrasound to measure carotid intima-media thickness, and cardiovascular MRI are established modalities for describing longitudinal changes in the quantity and quality of atherosclerotic plaque. An increasing number of clinical trials are using radiologic measures of subclinical atherosclerosis as surrogate end points in lieu of the traditional "hard" end points of myocardial infarction and death. This approach has great appeal, as improvements in atherosclerosis imaging now enable the characterization of early atheromas and positive remodeling within the vessel wall before the plaque becomes obstructive. Additional prospective data correlating these surrogate end points with hard outcomes are needed to determine whether atherosclerosis regression will be the major determinant of future treatment strategies.

Imaging biomarkers of atherosclerosis

Atherosclerosis imaging plays a significant role in an understanding of the natural history of vascular disease and is increasingly used to assess the efficacy of novel therapeutics. Furthermore, the concepts of 'vulnerable plaque' and, more recently, of 'vulnerable patient' have driven cardiovascular imaging technologies to develop methods for expanded qualitative and quantitative analyses. Indeed, developmental efforts are underway to better demonstrate thin fibrous cap and large necrotic cores, and to determine the correlation between these findings and subsequent cardiovascular events. In this article, we consider a wide variety of cardiovascular imaging techniques that are used as biomarkers of atherosclerosis. These technologies include traditional imaging such as angiography, as well as advanced imaging techniques using both invasive and noninvasive approaches.

A "hot" topic in dyslipidemia management--"how to beat a flush": optimizing niacin tolerability to promote long-term treatment adherence and coronary disease prevention

Niacin is the most effective lipid-modifying agent for raising high-density lipoprotein cholesterol levels, but it also causes cutaneous vasodilation with flushing. To determine the frequency of flushing in clinical trials, as well as to delineate counseling and treatment approaches to prevent or manage flushing, a MEDLINE search was conducted of English-language literature from January 1, 1985, through April 7, 2009. This search used the title keywords niacin or nicotinic acid crossed with the Medical Subject Headings adverse effects and human. Niacin flushing is a receptor-mediated, mainly prostaglandin D(2)-driven phenomenon, the frequency, onset, and duration of which are largely determined by the distinct pharmacological and metabolic profiles of different niacin formulations. Subjective assessments include ratings of redness, warmth, itching, and tingling. In clinical trials, most (>60%) niacin users experienced mild or moderate flushing, which tended to decrease in frequency and severity with continued niacin treatment, even with advancing doses. Approximately 5% to 20% of patients discontinued treatment because of flushing. Flushing may be minimized by taking niacin with meals (or at bedtime with a low-fat snack), avoiding exacerbating factors (alcohol or hot beverages), and taking 325 mg of aspirin 30 minutes before niacin dosing. The current review advocates an initially slow niacin dose escalation from 0.5 to 1.0 g/d during 8 weeks and then from 1.0 to 2.0 g in a single titration step (if tolerated). Through effective counseling, treatment prophylaxis with aspirin, and careful dose escalation, adherence to niacin treatment can be improved significantly. Wider implementation of these measures should enable higher proportions of patients to reach sufficient niacin doses over time to prevent cardiovascular events.

Completeness of carotid intima media thickness measurements depends on body composition: the RADIANCE 1 and 2 trials

AIM

Ultrasound protocols to measure carotid intima media thickness (CIMT) differ considerably with regard to the inclusion of the number of carotid segments and angles used. Detailed information on the completeness of CIMT information is often lacking in published reports, and at most, overall percentages are presented. We therefore decided to study the completeness of CIMT measurements and its relation with vascular risk factors using data from two CIMT intervention studies: one among familial hypercholesterolemia (FH) patients, the Rating Atherosclerotic Disease change by Imaging With A New CETP Inhibitor (RADIANCE 1), and one among mixed dyslipidemia (MD) patients, the Rating Atherosclerotic Disease change by Imaging With A New CETP Inhibitor (RADIANCE 2).

METHODS

We used baseline ultrasound scans from the RADIANCE 1 (n=872) and RADIANCE 2 (n=752) studies. CIMT images were recorded for 12 artery-wall combinations (near and far walls of the left and right common carotid artery (CCA), bifurcation (BIF) and internal carotid artery (ICA) segments) at 4 set angles, resulting in 48 possible measurements per patient. The presence or absence of CIMT measurements was assessed per artery-wall combination and per angle. The relation between completeness and patient characteristics was evaluated with logistic regression analysis.

RESULTS

In 89% of the FH patients, information on CIMT could be obtained on all twelve carotid segments, and in 7.6%, eleven segments had CIMT information (nearly complete 96.6%). For MD patients this was 74.6% and 17.9%, respectively (nearly complete: 92.5%). Increased body mass index and increased waist circumference were significantly (p=0.01) related to less complete data in FH patients. For MD patients, relations were seen with increased waist circumference (p<0.01). Segment-specific data indicated that in FH patients, completeness was less for the near wall of the left (96%) and right internal carotid artery (94%) as compared to other segments (all >98%). In MD patients, completeness was lower for the near wall of both the right and left carotid arteries: 86.0% and 90.8%, respectively, as compared to other segments (all >97%).

CONCLUSIONS

With the current ultrasound protocols it is possible to obtain a very high level of completeness. Apart from the population studied, body mass index and waist circumference are important in achieving complete CIMT measurements.

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.

Meta-analysis of the effect of nicotinic acid alone or in combination on cardiovascular events and atherosclerosis

OBJECTIVE

High-density lipoprotein cholesterol (HDL-C) concentration is a strong predictor of cardiovascular events in both naïve and statin-treated patients. Nicotinic acid is an attractive option for decreasing residual risk in statin-treated or statin-intolerant patients since it increases HDL-C by up to 20% and decreases low-density lipoprotein cholesterol and lipoprotein(a) plasma concentrations.

METHODS

We performed a computerized PubMed literature search that focused on clinical trials evaluating niacin, alone or in combination with other lipid-lowering drugs, published between January 1966 and August 2008.

RESULTS

Among 587 citations, 29 full articles were read and 14 were eligible for inclusion. Overall 11 randomized controlled trials enrolled 2682 patients in the active group and 3934 in the control group. In primary analysis, niacin significantly reduced major coronary events (relative odds reduction=25%, 95% CI 13, 35), stroke (26%, 95% CI=8, 41) and any cardiovascular events (27%, 95% CI=15, 37). Except for stroke, the pooled between-group difference remained significant in sensitivity analysis excluding the largest trial. In comparison with the non-niacin group, more patients in the niacin group had regression of coronary atherosclerosis (relative increase=92%, 95% CI=39, 67) whereas the rate of patients with progression decreased by 41%, 95% CI=25, 53. Similar effects of niacin were found on carotid intima thickness with a weighted mean difference in annual change of -17 microm/year (95% CI=-22, -12).

CONCLUSIONS

Although the studies were conducted before statin therapy become standard care, and mostly in patients in secondary prevention, with various dosages of nicotinic acid 1-3g/day, this meta-analysis found positive effects of niacin alone or in combination on all cardiovascular events and on atherosclerosis evolution.