The importance of distinguishing between diffuse carotid intima-media thickening and focal plaque

Prognostic impact of carotid plaque imaging using total plaque area added to SCORE2 in middle-aged subjects: the ARteris Cardiovascular Outcome (ARCO) cohort study

AIMS

Many cardiovascular events occur in seemingly healthy individuals.We set out to assess the predictive value of atherosclerosis imaging in combination with cardiovascular risk calculators in subjects aged 40-65 years.

METHODS

We compared PROCAM (PROspective CArdiovascular Münster study), SCORE (Systematic COronary Risk Evaluation) and SCORE2 with carotid ultrasound (total plaque area, TPA) in subjects without cardiovascular disease. In this prospective cohort study, follow-up was obtained by phone or mail from patients; or from clinical records, if needed.

RESULTS

In 2842 subjects (mean age 50±8 years; 38% women), cardiovascular events occurred in 154 (5.4%) of them over an mean follow-up period of 5.9 (range 1-12) years, specifically: 41 cases of AMI (myocardial infarction), 16 strokes, 21 CABG (coronary artery bypass grafting), 41 PTCA (percutaneous transluminal coronary angioplasty) and 35 CAD (coronary artery disease). Mean PROCAM risk was 5±6%, mean SCORE risk was 1.3±1.6% and mean SCORE2 risk was 5±3%. Both for the primary outcome (major adverse cardiovascular events, MACEs, i.e. AMI + strokes) and the secondary outcome (atherosclerotic cardiovascular disease, ASCVD, i.e. MACEs + CABG + CAD + PTCA), hazards increased significantly for TPA tertiles and SCORE2 post-test risk between 6.7 to 12.8 after adjustment for risk factors (age, smoke, sex, systolic blood pressure, lipids, medication) and after adjustment for results from PROCAM, SCORE and SCORE2. Model performance was statistically improved regarding model fit in all models using TPA. Net reclassification improvement for SCORE2 with TPA post-test risk increased significantly by 24% for MACEs (p = 0.01) and 39% for ASCVD (p <0.0001).

CONCLUSIONS

Integration of TPA post-test risk into SCORE2 adds prognostic information, supporting the use of carotid ultrasound when assessing ASCVD risk in subjects aged 40-65 years.

Reduced progression of carotid intima media thickness by personalised pictorial presentation of subclinical atherosclerosis in VIPVIZA-A randomised controlled trial

OBJECTIVES

Reduced progression of atherosclerosis can decrease the risk of cardiovascular disease (CVD). This study aimed at evaluating the effect of a pictorial intervention showing atherosclerotic severity on the progression of carotid atherosclerosis.

METHODS

A prospective randomised open-label blinded end-point trial with participants aged 40-60 years enroled from a routine CVD prevention programme. The intervention group (n: 1575) and their treating physicians received an image based presentation of subclinical atherosclerotic severity measured by carotid ultrasound. The control group (n: 1579) did not receive any information about ultrasound results. Carotid ultrasound at baseline and at 3-year follow-up contained plaque detection and measurements of carotid intima media thickness (cIMT). The left, right and bilateral-mean-cIMT, plaque prevalence and total plaque area (TPA) at 3-year follow-up were compared between groups. Significance level was set to p = 0.01 to adjust for multiple comparisons.

RESULTS

The intervention group revealed reduced cIMT progression in the left-mean-cIMT of -0.011 mm (p = 0.001) compared with the control group. The intervention effect on cIMT progression was most prominent in individuals with increased cIMT and plaque prevalence at baseline (-0.021 mm, p = 0.005). There were no differences in progression between groups for the right-and bilateral-mean-cIMT (-0.005 mm, p = 0.223 and -0.005 mm, p = 0.036, respectively), nor any differences between groups for plaque prevalence or TPA (odds ratio 0.88, p = 0.09 and 0.89, p = 0.21, respectively).

CONCLUSION

Pictorial presentation of subclinical atherosclerotic severity sent to both the individual and their treating physician resulted in significantly reduced left cIMT progression. Pictorial presentation has the potential to increase adherence in CVD prevention.

Clinical Significance of Carotid Intima-Media Complex and Carotid Plaque Assessment by Ultrasound for the Prediction of Adverse Cardiovascular Events in Primary and Secondary Care Patients

Recently published recommendations from the American Society of Echocardiography on 'Carotid Arterial Plaque Assessment by Ultrasound for the Characterization of Atherosclerosis and Evaluation of Cardiovascular Risk' provoked discussion once more on the potential clinical applications of carotid intima-media complex thickness (CIMT) and carotid plaque assessment in the context of cardiovascular risk in both primary and secondary care patients. This review paper addresses key issues and milestones regarding indications, assessment, technical aspects, recommendations, and interpretations of CIMT and carotid plaque findings. We discuss lacks of evidence, limitations, and possible future directions.

Three-dimensional ultrasound evaluation of the effects of pomegranate therapy on carotid plaque texture using locality preserving projection

BACKGROUND AND OBJECTIVE

Dietary supplements are expected to confer a smaller beneficial effect than medical treatments. Therefore, there is a need to develop cost-effective biomarkers that can demonstrate the efficacy of such supplements for carotid atherosclerosis. The aim of this study is to develop such a biomarker based on the changes of 376 plaque textural features measured from 3D ultrasound images.

METHODS

Since the number of features (376) was greater than the number of subjects (171) in this study, principal component analysis (PCA) was applied to reduce the dimensionality of feature vectors. To generate a scalar biomarker for each subject, elements in the reduced feature vectors produced by PCA were weighted using locality preserving projections (LPP) to capture essential patterns exhibited locally in the feature space. 96 subjects treated by pomegranate juice and tablets, and 75 subjects receiving placebo-matching juice and tablets were evaluated in this study. The discriminative power of the proposed biomarker was evaluated and compared with existing biomarkers using t-tests. As the cost of a clinical trial is directly related to the number of subjects enrolled, the cost-effectiveness of the proposed biomarker was evaluated by sample size estimation.

RESULTS

The proposed biomarker was more able to discriminate plaque changes exhibited by the pomegranate and placebo groups than total plaque volume (TPV) according to the result of t-tests (TPV: p=0.34, Proposed biomarker: p=1.5×10^-5). The sample size required by the new biomarker to detect a significant effect was 20 times smaller than that required by TPV.

CONCLUSION

With the increase in cost-effectiveness afforded by the proposed biomarker, more proof-of-principle studies for novel treatment options could be performed.

Definition of common carotid wall thickness affects risk classification in relation to degree of internal carotid artery stenosis: the Plaque At RISK (PARISK) study

Background

Mean or maximal intima-media thickness (IMT) is commonly used as surrogate endpoint in intervention studies. However, the effect of normalization by surrounding or median IMT or by diameter is unknown. In addition, it is unclear whether IMT inhomogeneity is a useful predictor beyond common wall parameters like maximal wall thickness, either absolute or normalized to IMT or lumen size. We investigated the interrelationship of common carotid artery (CCA) thickness parameters and their association with the ipsilateral internal carotid artery (ICA) stenosis degree.

Methods

CCA thickness parameters were extracted by edge detection applied to ultrasound B-mode recordings of 240 patients. Degree of ICA stenosis was determined from CT angiography.

Results

Normalization of maximal CCA wall thickness to median IMT leads to large variations. Higher CCA thickness parameter values are associated with a higher degree of ipsilateral ICA stenosis (p < 0.001), though IMT inhomogeneity does not provide extra information. When the ratio of wall thickness and diameter instead of absolute maximal wall thickness is used as risk marker for having moderate ipsilateral ICA stenosis (>50%), 55 arteries (15%) are reclassified to another risk category.

Conclusions

It is more reasonable to normalize maximal wall thickness to end-diastolic diameter rather than to IMT, affecting risk classification and suggesting modification of the Mannheim criteria.

Trial registration

Clinical trials.gov NCT01208025.

Effects of aldosterone on human atherosclerosis: plasma aldosterone and progression of carotid plaque

BACKGROUND

In animal models, aldosterone has adverse cardiac and vascular effects independent of blood pressure, and these are ameliorated by spironolactone or eplerenone (mineralocorticoid receptor antagonists). Both agents reduce mortality in human systolic heart failure. We studied the effect of plasma aldosterone on human carotid atherosclerosis.

METHODS

The effect of plasma aldosterone on progression of carotid total plaque area (TPA) was studied using multiple linear regression, with variables that have previously been shown to maximally explain TPA variation (age, sex, total cholesterol, systolic blood pressure, diabetes, smoking, and medication for cholesterol and systolic blood pressure).

RESULTS

Complete data were available in 848 patients with progression of plaque from baseline to the following year and in 571 for progression in the second year. In stepwise linear regression, plasma aldosterone was the only independent predictor of plaque progression in the first year (P = 0.005) and in the second year (P = 0.001).

CONCLUSIONS

Plasma aldosterone is associated with progression of atherosclerosis. We are now planning to test the effects of mineralocorticoid receptor antagonism on plaque progression.

Advances in noninvasive imaging for evaluating clinical risk and guiding therapy in carotid atherosclerosis

Managing asymptomatic carotid atherosclerosis with a view to preventing ischemic stroke is a challenging task. As the annual risk of stroke in untreated asymptomatic patients on average is less than the risk of surgical intervention, the key question is how to identify those asymptomatic individuals whose risk of stroke is elevated and who would benefit from surgery, while sparing low-risk asymptomatic patients from the risks of surgical intervention. The advent of a multitude of noninvasive carotid imaging techniques offers an opportunity to improve risk stratification in patients and to monitor the response to medical therapies; assessing efficacy at individual and population levels. As part of this, plaque measurement techniques (using ultrasound, computed tomography or MRI) may be employed in monitoring plaque/component regression and progression. Novel imaging applications targeted to plaque characteristics, inflammation and neovascularization, including contrast-enhanced ultrasound and MRI, dynamic contrast-enhanced MRI, and fluorodeoxyglucose-PET, are also being explored. Ultimately, noninvasive imaging and other advances in risk stratification aim to improve and individualize the management of patients with carotid atherosclerosis.

Treating arteries instead of risk factors: a paradigm change in management of atherosclerosis

BACKGROUND AND PURPOSE

Until recently, atherosclerosis was thought to be inexorably progressive. Beginning in 2001 and implemented in our vascular prevention clinics by 2003, we have been treating arteries rather than risk factors. We studied the proportion of patients with plaque progression vs regression before and after this change in paradigm.

METHODS

Carotid total plaque area was measured by ultrasound at baseline and during follow-up. Before 2003, patients were treated according to consensus guidelines. After 2003, patients with plaque progression were treated more intensively, with the explicit goal of halting plaque progression or achieving regression.

RESULTS

Four thousand three-hundred seventy-eight patients had serial plaque measurements in a given year between 1997 and 2007; 47% were female. Mean age at time of referral was 60 (SD, 15); this increased steeply (from age 50 to 62 years over the first 5 years) as we focused on stroke prevention. The annual rate of plaque progression increased steeply as the clinic populations aged but then abruptly decreased after implementation of the new approach to therapy. Before 2003, approximately half the patients had plaque progression and approximately 25% had regression; by 2005, this had reversed. Changes in plasma lipids show that the differences were attributable to plaque measurement, not simply more intensive therapy for all patients. By 2007, patients with progression had lower levels of low-density lipoprotein than those with regression.

CONCLUSIONS

Treating arteries without measuring plaque would be like treating hypertension without measuring blood pressure. A clinical trial to test this approach is being designed.

Dietary intervention to reverse carotid atherosclerosis

BACKGROUND

It is currently unknown whether dietary weight loss interventions can induce regression of carotid atherosclerosis.

METHODS AND RESULTS

In a 2-year Dietary Intervention Randomized Controlled Trial-Carotid (DIRECT-Carotid) study, participants were randomized to low-fat, Mediterranean, or low-carbohydrate diets and were followed for changes in carotid artery intima-media thickness, measured with standard B-mode ultrasound, and carotid vessel wall volume (VWV), measured with carotid 3D ultrasound. Of 140 complete images of participants (aged 51 years; body mass index, 30 kg/m(2); 88% men), higher baseline carotid VWV was associated with increased intima-media thickness, age, male sex, baseline weight, blood pressure, and insulin levels (P<0.05 for all). After 2 years of dietary intervention, we observed a significant 5% regression in mean carotid VWV (-58.1 mm(3;) 95% confidence interval, -81.0 to -35.1 mm(3); P<0.001), with no differences in the low-fat, Mediterranean, or low-carbohydrate groups (-60.69 mm(3), -37.69 mm(3), -84.33 mm(3), respectively; P=0.28). Mean change in intima-media thickness was -1.1% (P=0.18). A reduction in the ratio of apolipoprotein B(100) to apolipoprotein A1 was observed in the low-carbohydrate compared with the low-fat group (P=0.001). Participants who exhibited carotid VWV regression (mean decrease, -128.0 mm(3); 95% confidence interval, -148.1 to -107.9 mm(3)) compared with participants who exhibited progression (mean increase, +89.6 mm(3); 95% confidence interval, +66.6 to +112.6 mm(3)) had achieved greater weight loss (-5.3 versus -3.2 kg; P=0.03), greater decreases in systolic blood pressure (-6.8 versus -1.1 mm Hg; P=0.009) and total homocysteine (-0.06 versus +1.44 mumol/L; P=0.04), and a higher increase of apolipoprotein A1 (+0.05 versus -0.00 g/L; P=0.06). In multivariate regression models, only the decrease in systolic blood pressure remained a significant independent modifiable predictor of subsequent greater regression in both carotid VWV (beta=0.23; P=0.01) and intima-media thickness (beta=0.28; P=0.008) levels.

CONCLUSIONS

Two-year weight loss diets can induce a significant regression of measurable carotid VWV. The effect is similar in low-fat, Mediterranean, or low-carbohydrate strategies and appears to be mediated mainly by the weight loss-induced decline in blood pressure. Clinical Trial Registration- http://www.clinicaltrials.gov. Unique Identifier: NCT00160108.

Carotid plaque compared with intima-media thickness as a predictor of coronary and cerebrovascular disease

Atherosclerosis is the underlying cause of most myocardial infarction (MI) and ischemic strokes. B-mode ultrasound of carotid arteries provides measures of intima-media thickness (IMT) and plaques, both widely used as surrogate measures of cardiovascular disease. Although IMT and plaques are highly intercorrelated, IMT's role as a marker of atherosclerosis has been questioned, especially when measurements include the common carotid artery (CCA) only. Plaque and intima-media thickening may reflect different biological aspects of atherogenesis with distinctive relations to clinical vascular disease. Plaque measured in the carotid bulb or internal carotid artery is stronger related to hyperlipidemia and smoking and is a stronger predictor for MI, whereas CCA-IMT is stronger related to hypertension and ischemic stroke. Echolucent plaque morphology (ie, lipid-rich plaques) seems to increase the risk for MI and stroke. New evidence suggests that total plaque area is the most strongly predictive of cardiovascular risk of the ultrasound phenotypes.