Imaging arterial wall disease

Aortic, carotid intima-media thickness and flow- mediated dilation as markers of early atherosclerosis in a cohort of pediatric patients with rheumatic diseases

The aims of this study were to identify the presence of endothelial dysfunction as a marker of early atherosclerosis by measuring aortic and carotid intimal-medial thickness (aIMT and cIMT) and flow-mediated dilation (FMD) and their correlation with traditional and no traditional risk factors for atherosclerosis in children with rheumatic diseases. Thirty-nine patients (mean age 15.3 ± 5.7 years), 23 juvenile idiopathic arthritis, 9 juvenile spondyloarthropathies, 7 connective tissue diseases (mean disease duration and onset respectively 5 ± 3.6 and 10 ± 5 years), and 52 healthy children matched for sex and age were enrolled. Demographic data (age, sex, familiarity for cardiovascular disease), traditional risk factors for atherosclerosis (BMI, active and passive smoking, dyslipidemia), activity disease indexes (reactive count protein, erythrocyte sedimentation rate) autoantibodies, and complement tests were collected. aIMT, cIMT, and FMD were assessed following a standardized protocol by high-resolution ultrasonography. Patients resulted significantly more exposed to passive smoking and had a lower BMI and higher homocysteine level than controls. cIMT and aIMT were significantly higher in patients than controls (p < 0.001) and correlated with age at diagnosis (p < 0.001 r 0.516 and 0.706, respectively) but not with mean disease duration. FMD % was significantly reduced in patients compared to controls (p < 0.001). Subclinical atherosclerosis occurs in pediatric rheumatic diseases, mainly in early onset forms, and aIMT is an earlier marker of preclinical atherosclerosis. Premature endothelial dysfunction could be included in the follow-up of children with rheumatic disorders to plan prevention strategies of cardiovascular disease already in pediatrics.

What Should We Do with Asymptomatic Carotid Stenosis?

The benefit of prophylactic carotid endarterectomy (CEA) for patients with asymptomatic severe carotid stenosis in the major randomised surgical studies was small, expensive and may now be absorbed by improvements in best practice medical intervention. Strategies to identify patients with high stroke risk are needed. If surgical intervention is to be considered the complication rates of individual surgeons should be available. Clinicians will differ in their interpretation of the same published data. Maintaining professional relationships with clinicians from different disciplines often involves compromise. As such, the management of a patient will, in part, depend on what kind of specialist the patient is referred to. The clinician's discussion with patients about this complex issue must be flexible to accommodate differing patient expectations. Ideally, patients prepared to undergo surgical procedures should be monitored in a trial setting or as part of an audited review process to increase our understanding of current practice outcomes.

Aortic Intima-Media Thickness as an Early Marker of Atherosclerosis in Children With Inflammatory Bowel Disease

OBJECTIVES

The aims of this study were to determine the presence of endothelial dysfunction by measuring aortic intima-media thickness (aIMT) and carotid intima-media thickness (cIMT) and to evaluate the role of traditional risk factors for premature atherosclerosis in children with inflammatory bowel disease (IBD).

METHODS

Thirty-four children with IBD (25 Crohn disease [CD] and 9 ulcerative colitis [UC]; mean age 11.1 years) and 27 healthy subjects matched for sex and age were enrolled. In all of the patients, demographic characteristics and risk factors for atherosclerosis (age, sex, body mass index, blood pressure, dyslipidemia, active and passive smoking, and family history for cardiovascular diseases), CD and UC clinical activity scores, and inflammatory markers were evaluated. aIMT and cIMT were measured by high-resolution B-mode ultrasound.

RESULTS

aIMT was significantly higher in patients than in controls (P < 0.0005). No significant differences were found for cIMT, although the carotid thickness was higher in patients with IBD than in healthy subjects. At a univariate analysis, inflammatory markers levels and tobacco smoking exposure were significantly related to higher aIMT values, whereas in a multivariate regression model, the inflammatory status was the only independent variable correlated with high aIMT.

CONCLUSIONS

aIMT is an earlier marker of preclinical atherosclerosis than cIMT in young children with active IBD. The inflammatory status and the smoking exposure are significantly correlated with the premature endothelial dysfunction. These data emphasize the importance of controlling the chronic intestinal inflammation and endorsing smoke-free environments for children and adolescents with IBD.

Non-invasive vascular radial/circumferential strain imaging and wall shear rate estimation using video images of diagnostic ultrasound

The aim of this work was to develop a convenient method for radial/circumferential strain imaging and shear rate estimation that could be used as a supplement to the current routine screening for carotid atherosclerosis using video images of diagnostic ultrasound. A reflection model-based correction for gray-scale non-uniform distribution was applied to B-mode video images before strain estimation to improve the accuracy of radial/circumferential strain imaging when applied to vessel transverse cross sections. The incremental and cumulative radial/circumferential strain images can then be calculated based on the displacement field between consecutive B-mode images. Finally, the transverse Doppler spectra acquired at different depths along the vessel diameter were used to construct the spatially matched instantaneous wall shear values in a cardiac cycle. Vessel phantom simulation results revealed that the signal-to-noise ratio and contrast-to-noise ratio of the radial and circumferential strain images were increased by 2.8 and 5.9 dB and by 2.3 and 4.4 dB, respectively, after non-uniform correction. Preliminary results for 17 patients indicated that the accuracy of radial/circumferential strain images was improved in the lateral direction after non-uniform correction. The peak-to-peak value of incremental strain and the maximum cumulative strain for calcified plaques are evidently lower than those for other plaque types, and the echolucent plaques had higher values, on average, than the mixed plaques. Moreover, low oscillating wall shear rate values, found near the plaque and stenosis regions, are closely related to plaque formation. In conclusion, the method described can provide additional valuable results as a supplement to the current routine ultrasound examination for carotid atherosclerosis and, therefore, has significant potential as a feasible screening method for atherosclerosis diagnosis in the future.

Premature subclinical atherosclerosis in pediatric inflammatory bowel disease

OBJECTIVES

To investigate the risk for developing an early endothelial dysfunction based on increased intima media thickness (IMT) and reduced flow-mediated dilation (FMD) in children with inflammatory bowel disease (IBD), and to evaluate the role of traditional and nontraditional risk factors in determining premature atherosclerosis.

STUDY DESIGN

We studied 27 patients with Crohn's disease (CD) and 25 patients with ulcerative colitis (UC) (mean age, 15.2 years; mean duration of disease, 48.05 months); 31 subjects served as controls. Demographic data (age, sex, family history of diabetes, cardiovascular disease, hypertension, hypercholesterolemia), traditional risk factors for atherosclerosis (blood pressure, body mass index, active and passive smoking, dyslipidemia), and UC and CD activity indexes (Pediatric Ulcerative Colitis Activity Index and Pediatric Crohn's Disease Activity Index, respectively) were collected. The IMT of the carotid arteries was measured by high-resolution B-mode ultrasound, and endothelial function was evaluated by FMD in the brachial artery in response to reactive hyperemia.

RESULTS

Compared with controls, patients with CD had significantly greater exposure to passive smoking and had lower body mass index and high-density lipoprotein cholesterol values. IMT was significantly higher in patients than controls (P < .0001), and the percentage of FMD was significantly lower in both patients with CD (P < .0001) and patients with UC (P < .01) versus controls. In multivariate analysis, diagnosis of IBD was an independent risk factor for atherosclerosis.

CONCLUSION

Premature endothelial dysfunction occurs in pediatric IBD. This represents a new challenge in the management of pediatric IBD, leading to prevention strategies of cardiovascular disease.

Carotid enlargement and serum levels of von Willebrand factor in rheumatoid arthritis: a follow-up study

This follow-up study aimed to evaluate the relationship between serum levels of von Willebrand factor (vWf) and common carotid intima-media thickness (IMT) in patients with rheumatoid arthritis (RA). In the initial assessment, 34 female rheumatoid arthritis patients and 30 sex- and age-matched controls were included. The relationship among vWf serum levels, cardiovascular risk factors, and inflammation was initially assessed. The effects of these variables on carotid IMT were evaluated 5 years later. There were no significant differences between the RA patients and the controls in terms of IMT at the first evaluation. Five years later, the carotid IMT increased more significantly in RA patients if compared to controls (p < 0.001). The progression of carotid IMT significantly correlated with erythrocyte sedimentation rate (ESR) (r = 0.368, p = 0.032) and C-reactive protein (r = 0.506, p = 0.002). The progression of carotid IMT did not significantly correlate with vWf serum levels in the RA patients, although, at initial and repeated measurements, it showed statistically higher values of vWF in the RA patients compared to the control group (p < 0.01). The RA patients displayed accelerated development of atherosclerosis, as indicated by the increased IMT of carotid artery. Increased serum levels of vWF may suggest its potential role in cardiovascular risk prediction in RA patients.

Intima media thickness of the common carotid artery in vascular surgery patients: a predictor of postoperative cardiovascular events

BACKGROUND

Cardiovascular (CV) complications are the leading cause of morbidity and mortality in vascular surgery patients. The Revised Cardiac Risk (RCR) index, identifying cardiac risk factors, is commonly used for preoperative risk stratification. However, a more direct marker of the underlying atherosclerotic disease, such as the common carotid artery intimamedia thickness (CCA-IMT) may be of predictive value as well. The current study evaluated the prognostic value of the CCA-IMT for postoperative CV outcome.

METHODS

In 508 vascular surgery patients, the CCA-IMT was measured using high-resolution B-mode ultrasonography. We recorded the RCR factors: ischemic heart disease, heart failure, cerebrovascular disease, diabetes mellitus, and renal dysfunction. Repeated Troponin T measurements and electrocardiograms were performed postoperatively. The study end point was the composite of 30-day CV events and long-term CV mortality. Multivariable regression analyses were used to assess the additional value of CCA-IMT for the prediction of cardiac events.

RESULTS

In total, 30-day events and long-term cardiovascular mortality were noted in 122 (24%) and 81 (16%) patients, respectively. The optimal predictive value of CCA-IMT, using receiver-operating characteristic curve analysis, for the prediction of CV events was calculated to be 1.25 mm (sensitivity 70%, specificity 80%). An increased CCA-IMT was independently associated with 30-day CV events (OR 2.20, 95% CI 1.38-3.52) and long-term CV mortality (HR 6.88, 95% CI 4.11-11.50), respectively.

CONCLUSIONS

This study shows that an increased CCA-IMT has prognostic value in vascular surgery patients to predict 30-day CV events and long-term CV mortality, incremental to the RCR index.

Common carotid intima media thickness as a marker of clinical severity in patients with symptomatic extracranial carotid artery stenosis

OBJECTIVES

Increased common carotid artery intima-media thickness (CCA-IMT) is a risk factor for ischemic stroke and especially large vessel atherothrombotic infarction. However, the potential association of stroke severity with the intima-media thickening has not been previously studied. We sought to investigate the association between CCA-IMT and clinical severity of ischemic stroke in patients with symptomatic extracranial carotid artery stenosis (SCAS).

PATIENTS AND METHODS

Consecutive patients with acute, first-ever ischemic stroke and SCAS (50%-99%) were prospectively evaluated. All subjects underwent IMT measurements at the far wall of CCA. Stroke severity was assessed using the National Institute of Health Stroke Scale (NIHSS) on hospital admission and Barthel Ambulatory Index (BI) at hospital discharge.

RESULTS

CCA-IMT was strongly correlated to NIH (Spearman's correlation coefficient: r=0.546, p<0.001) and BI (r=-0.450, p<0.001) in the study population (n=102). A 0.1mm increase in CCA-IMT was independently associated with increasing NIHSS-scores on hospital admission (beta: 0.510; p<0.001) and decreasing BI-scores at hospital discharge (beta: -0.483; p<0.001) even after adjustment for demographic characteristics and cardiovascular risk factors. After including baseline stroke severity (NIHSS) in the multivariate linear regressions models evaluating early functional outcome, only NIHSS was independently related to BI (standardized linear regression coefficient: -0.776, p<0.001), while the initial association between IMT and BI did not retain its statistical significance (beta: -0.074, p=0.276).

CONCLUSIONS

Increased CCA-IMT is independently associated with more severe stroke on admission in patients with SCAS.

Lack of difference in the intimal medial thickness between the left and right carotid arteries in the young

BACKGROUND

Carotid intimal medial thickening (c-IMT) is an established surrogate marker for atherosclerosis. There have been sporadic reports about an increase of c-IMT on the left carotid artery among populations with a mean age of +/-50 years.

OBJECTIVE

The purpose of this study was to evaluate whether there is a difference in c-IMT between the two carotid arteries in a group of young healthy adults.

METHODS

Ninety-eight healthy adults with a mean age of 28 years underwent blood tests to evaluate various cardiovascular risk factors as well as automated ultrasonic measurements of their c-IMT on both carotid arteries.

RESULTS

No significant difference was noted between c-IMT on both sides. In fact, the c-IMT on left carotid artery in men (n = 52) was 0.625 +/- 0.078 mm while on the right carotid it was 0.626 +/- 0.075 mm (P = 0.884). The values for women (n = 46) were 0.615 +/- 0.059 mm and for men 0.622 +/- 0.0618 mm (P = 0.582), respectively.

CONCLUSION

As opposed to a noted increase of c-IMT on the left carotid artery in older individuals, we did not find this difference in a group of young and relatively healthy adults. It is possible that if mechanical stress forces contribute to an enhanced left c-IMT, it takes a relatively long time to become evident.

Inflammatory bowel disease is not associated with increased intimal media thickening

OBJECTIVES

Several studies have suggested that chronic inflammatory diseases might be associated with an acceleration of the atherosclerotic process. There is little information on the effect of chronic inflammation in patients with inflammatory bowel disease (IBD) on the presence of increased intimal media thickening (IMT), a surrogate marker for atherosclerotic diseases. In this work our aim was to determine whether IBD is a risk factor for increased IMT.

METHODS

IMT was measured by ultrasound of the carotid arteries; a computer software program was used to analyze 80-100 independent IMT samples from each carotid artery segment in 61 patients with IBD (45 with Crohn's disease and 16 with ulcerative colitis) and in 61 controls matched for age (+/-2 yr), sex, body mass index (BMI, +/-2 kg/m(2)), and smoking status.

RESULTS

Inflammatory markers (erythrocyte sedimentation rate, fibrinogen, high-sensitive C-reactive protein) were significantly (P<0.001) elevated in IBD patients compared with controls. Even though there was a disease duration of 8.7 +/- 8.5 yr, the mean IMT of IBD patients was similar to that of the control group (0.66 +/- 0.09 vs 0.64 +/- 0.07 mm; P>0.05).

CONCLUSIONS

Despite chronic inflammation, IBD patients had IMT values similar to those of the controls. Thus, unlike other inflammatory diseases, IBD appears not to be a risk factor for accelerated atherosclerosis.

Prevalence and Risk Factors of Atherosclerosis in Patients with Psoriatic Arthritis

OBJECTIVES

To evaluate the extent of subclinical atherosclerosis by measuring the intima-media wall thickness (IMT) of the common carotid artery in patients with psoriatic arthritis (PsA) and to identify vascular risk factors associated with PsA.

METHODS

Forty-seven patients with PsA were compared with 100 allegedly healthy subjects. Carotid duplex scanning was used to measure common carotid artery IMT. Traditional risk factors, such as gender, age, body mass index (BMI), hypertension, smoking, and lipids were checked. Assessment of PsA activity included clinical patterns of involvement, degree of severity, duration of morning stiffness, number of tender and swollen joints, degree of pain and fatigue, the Bath Ankylosing Spondylitis Disease Activity Index, the Psoriasis Area and Severity Index, erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), and fibrinogen.

RESULTS

The average IMT (mean +/- standard deviation) for PsA patients was significantly higher compared with controls (0.76 +/- 0.11 versus 0.64 +/- 0.27, respectively, P < 0.00001) for the whole group and after adjustment for age, gender, BMI, hypertension, and hyperlipidemia. The PsA subjects had significantly higher levels of hypertension, hyperlipidemia, ESR, CRP, and fibrinogen, and their average IMT significantly correlated with age, BMI, duration of skin and joint disease, spine involvement, ESR, and fibrinogen. IMT did not correlate with the presence of oligo- or polyarthritis but was increased in patients with clinical spinal involvement. IMT was not associated with the degree of severity or the use of different therapies for PsA, including methotrexate or tumor necrosis factor-alpha-blocking agents.

CONCLUSIONS

PsA patients exhibited greater IMT than healthy controls. Increased IMT independently correlated with parameters of disease activity and conventional risk factors of atherosclerosis.

Early Motor Evoked Potentials in Acute Stroke: Adjunctive Measure to MRI for Assessment of Prognosis in Acute Stroke within 6 Hours

BACKGROUND

In acute stroke, a magnetic resonance (MR) perfusion-weighted imaging (PWI) and diffusion-weighted imaging (DWI) mismatch (PWI>DWI mismatch) may indicate tissue at risk for infarction and poor prognosis. However, different to early enthusiasm about this surrogate marker, its validity has shown several drawbacks in individual patients. Rather than relying on imaging, we evaluated motor evoked potentials (MEP) as a measure of cerebral function in the acute stroke setting.

METHODS

Thirteen patients with acute hemiparetic stroke underwent time to peak PWI and DWI within 6 h after onset as well as recordings of early MEP of first dorsal interosseous muscles. Outcome was assessed by the Unified Neurological Stroke Scale and Barthel Index at day 42.

RESULTS

Of 8 patients with PWI>DWI mismatch, 4 patients with normal MEP had a good clinical outcome and 4 patients with absent or pathological MEP had an unfavourable outcome (p < 0.05, Fisher's exact test). In all patients without PWI>DWI mismatch, MEP findings predicted clinical outcome. Normal MEP at day 0--but not PWI/DWI findings--significantly correlated with a good clinical outcome.

CONCLUSIONS

Early MEP recordings in acute stroke patients provide valid prognostic information; they may become more useful for specific treatment decisions than presently available MRI surrogate parameters.

Reproducibility of histological assessment of carotid plaque: implications for studies of carotid imaging

BACKGROUND

Thromboembolism from carotid plaque is an important cause of stroke. Identification of unstable plaque would therefore be clinically useful. Unfortunately, studies of carotid plaque imaging have shown poor agreement with histology. However, this may be due to inconsistent methods and the variability of assessments of carotid plaque histology, rather than inadequate imaging.

METHODS

We assessed the reproducibility of histological assessment in 60 plaques, and section-to-section variability along the length of 26 plaques.

RESULTS

Kappa values ranged from 0.35 to 0.89 and from 0.44 to 0.68, respectively, for intra- and inter-observer reproducibility. There was considerable section-to-section variability within plaques.

CONCLUSIONS

The accuracy of imaging of carotid plaque morphology will be underestimated unless variability in the histology assessment is taken into account.

A new method for analysis of motion of carotid plaques from RF ultrasound images

Motion of carotid artery plaques during the cardiac cycle may contribute to plaque disruption and embolism. We have developed a computerized method that objectively analyzes such motion from a sequence of ultrasound (US) radiofrequency (RF) images. A displacement vector map is obtained by 2-D correlation of local areas in consecutive images. From this map, motion dynamics can be quantified and presented as function of time, spatial (image) coordinates or as single numbers. Correct functionality has been verified on laboratory data. Applied to patient data, the method gives temporal results that correlate well with ECG data and the calculated peak systolic velocities of typically 10 mm/s agree well with values reported in the literature. The spatial analysis demonstrates that different plaque regions may exhibit different motion patterns that may cause internal stress, leading to fissures and plaque disruption. Thus, the motion analysis method may provide new and important information about the plaque characteristics and the prospective risk of cerebrovascular events.