The impact of carotid plaque presence and morphology on mortality outcome in cardiological patients

The Evolution of Carotid Surgery

This review traces the evolution of carotid surgery from its ancient roots to modern practice. The first significant appreciation of the carotid arteries' role in cerebral ischemia was made by Johann Jakob Wepfer in his 1658 book on apoplexy, which described the separate blood supply to each cerebral hemisphere by the carotid arteries. The 16th-19th centuries saw initial attempts at carotid ligation, while the 20th century marked significant advancements. The first carotid endarterectomy (CEA) by DeBakey, Cooley, and Eastcott in the 1950s paved the way for a new technique in carotid surgery and many subsequent refinements in surgical techniques related to CEA. The latter half of the 20th century brought innovations such as patch angioplasty, microsurgical techniques, and intraoperative shunting, significantly improving outcomes. Pivotal clinical trials established CEA as the standard treatment for symptomatic carotid stenosis. The emergence of carotid artery stenting (CAS) in the 1980s introduced a less invasive alternative, sparking ongoing debates about optimal treatment strategies. Recent developments include transcarotid artery revascularization (TCAR) and transfemoral CAS, with studies comparing their efficacy to traditional CEA. Current research focuses on plaque morphology and novel diagnostic factors to further personalize treatment strategies for carotid artery stenosis.

Comparing Focused-Tracked and Plane Wave-Tracked ARFI Log(VoA) In Silico and in Application to Human Carotid Atherosclerotic Plaque, Ex Vivo

A significant risk factor for ischemic stroke is carotid atherosclerotic plaque that is susceptible to rupture, with rupture potential conveyed by plaque morphology. Human carotid plaque composition and structure have been delineated noninvasively and in vivo by evaluating log(VoA), a parameter derived as the decadic log of the second time derivative of displacement induced by an acoustic radiation force impulse (ARFI). In prior work, ARFI-induced displacement was measured using conventional focused tracking; however, this requires a long data acquisition period, thereby reducing framerate. We herein evaluate if ARFI log(VoA) framerate can be increased without a reduction in plaque imaging performance using plane wave tracking instead. In silico, both focused- and plane wave-tracked log(VoA) decreased with increasing echobrightness, quantified as signal-to-noise ratio (SNR), but did not vary with material elasticity for SNRs below 40 dB. For SNRs of 40-60 dB, both focused- and plane wave-tracked log(VoA) varied with SNR and material elasticity. Above 60 dB SNR, both focused- and plane wave-tracked log(VoA) varied with material elasticity alone. This suggests that log(VoA) discriminates features according to a combination of their echobrightness and mechanical property. Further, while both focused- and plane-wave tracked log(VoA) values were artifactually inflated by mechanical reflections at inclusion boundaries, plane wave-tracked log(VoA) was more strongly impacted by off-axis scattering. Applied to three excised human cadaveric carotid plaques with spatially aligned histological validation, both log(VoA) methods detected regions of lipid, collagen, and calcium (CAL) deposits. These findings support that plane wave tracking performs comparably to focused tracking for log(VoA) imaging and that plane wave-tracked log(VoA) is a viable approach to discriminating clinically relevant atherosclerotic plaque features at a 30-fold higher framerate than by focused tracking.

Sample Preparation of Atherosclerotic Plaque for SAXS/WAXS Experimentation

Atherosclerosis is often described as a single disease entity; however, the morphology of each plaque is unique to the individual. The field currently lacks a technique that can discriminate stable from unstable plaques, to identify those at risk of a thromboembolic event. Small- and wide-angle X-ray scattering (SAXS/WAXS) holds the potential to be able to identify key materials present in a plaque, such as cholesterol species, collagen, low-density lipoproteins (LDLs), and hydroxyapatite. Protocols have been established for the preparation of excised human atherosclerotic tissue that are investigated herein. This includes the fixing, sectioning, and substrate selection of the sample. Through several sample preparation methods, vast improvements have been made to sample-to-noise ratio and background subtraction.

Comparative assessment of the signs of instability of atherosclerotic plaques in the carotid arteries in elderly patients with acute coronary syndrome with duplex scanning and computed tomography angiography

Aim. To study the signs of instability of atherosclerotic plaques (ASP) in the carotid arteries in elderly patients with acute coronary syndrome (ACS) in the comparative aspect of duplex ultrasound scanning (DUS) and computed tomography angiography (CT).

Material and methods. 27 patients with ACS (75 years and over) were included in the study. The signs of instability of ASP were assessed according to DUS and CT.

Results. The signs of instability of ASP according to DUS were detected in 85,7%, according to CT — in 84,6%. The following signs were detected with DUS and CT: the presence of irregular plaque surface including signs of ulceration — 6,4 and 11,6% (p=0,021), positive remodeling — 3,8 and 3,8% (p=0,998), signs of local calcification — 23 and 25,9% (p=0,536), heterogenous structure — 55,1 and 46,8% (p=0,045), hypoechogenic component and low-density areas — 11,5 and 11,6% (p= 0,998). The correlation analysis showed high comparability of DUS and CT: irregular plaque surface with ulceration (K=0,624, p=0,02), positive remodeling (K=1, p<0,001), calcification (K=0,858, p<0,001), heterogenous structure (K=0,754, p<0,001), the presence of hypoechogenic component and low-density areas (K=1, p<0,001).

Conclusion. The study of elderly patients with ACS found high comparability of DUS and CT in the definition of the signs of instability of ASP in the carotid arteries. It is possible to use DUS as a routine method for assessing carotid atherosclerosis in patients of this group, which can reduce the risk of complications during CT, shorten the examination time, and minimize economic costs.

Carotid Ultrasound Screening Programs in Rural Communities: A Systematic Review

Carotid atherosclerosis assessments inform about stroke and cardiovascular risk. It is known that stroke and cardiovascular disease (CVD) prevalence is higher in rural communities than in urban communities. We aimed to conduct a systematic review of rural carotid ultrasound screening programs to define carotid atherosclerosis using traditional and emerging imaging biomarkers, prevalence, and risk factors. We searched Ovid/MEDLINE, Ovid/EMBASE, SCOPUS and CINAHL from inception to 3 April 2020 for rural population studies that utilized carotid ultrasound screening for adults ≥40 years of age and free of known cerebrovascular disease. Studies were included if participants received a bilateral ultrasound scanning of the carotid arteries and reported at least one marker of carotid atherosclerosis pathology. A random effect meta-analyses calculated the estimated prevalence of carotid plaque. In total, 22/3461 articles that met all of the inclusion criteria were included. Studies reported increased intima media thickness (IMT), carotid plaque presence and carotid artery stenosis. There were no studies reporting on novel imaging markers, such as carotid stiffness, carotid plaque morphology or neovascularization. The overall random effect pooled prevalence of carotid plaque was 34.1% (95% CI, 33.6–35.0); the prevalence of increased IMT was 11.2–41.5%, and the prevalence of carotid artery stenosis was 0.4–16.0%. There is an absence of data necessary to understand the carotid atherosclerosis prevalence across global rural populations. Represented studies have focused on East Asian countries where a high burden of rural carotid artery disease has been reported. There is no rural evidence to guide the use of novel ultrasound carotid biomarkers such as stiffness or neovascularization.

Preprocedural Carotid Plaque Echolucency as a Predictor of In-Stent Intimal Restenosis after Carotid Artery Stenting

OBJECTIVES

In-stent intimal restenosis (ISR) caused by neointimal hyperplasia can develop <24 months after carotid artery stenting (CAS). The utility of plaque imaging by carotid ultrasonography (US) or magnetic resonance imaging (MRI) has been investigated for the prediction of ipsilateral stroke. We aimed to investigate whether these imaging techniques are useful for detecting carotid plaques prone to ISR.

MATERIALS AND METHODS

We examined 133 patients (mean age of 72.1 ± 8.4 years old) that received CAS at a single hospital from 2014 to 2018. A pre-CAS carotid plaque evaluation was performed by carotid angiography, duplex carotid US, and black-blood carotid artery MRI (BB-MRI). The mean stenosis rate was 71.0 ± 12.3% by the North American Symptomatic Carotid Endarterectomy Trial (NASCET) methods. Follow-up carotid angiography was performed 6 months after CAS in all patients according to a predefined protocol. ISR was defined as in-stent intimal hyperplasia more than 50% stenosed based on the NASCET criteria. The selection of the stent type was at the discretion of the treating physician. Predictors of ISR were determined by multivariate logistic regression analysis.

RESULTS

Follow-up angiography demonstrated ISR in 33 patients (24.8%). In 44 patients, more than two stents were deployed. Univariate logistic regression analyses demonstrated echolucent lesion, floating plaque, complete occlusive or pseudo-occlusive lesion, and closed-cell stent use as significantly associated with ISR (>50%). Multivariate logistic regression analysis demonstrated that echolucent lesion (OR 4.667, 95% CI 1.849-11.779) and closed-cell stent use (OR .378, 95% CI .148-.968) were significantly associated with ISR.

CONCLUSIONS

Preprocedural plaque characterization by carotid US appeared to be useful to predict ISR 6 months after CAS.

The TUDID Study - Background and Design of a Prospective Cohort

Prevalence of both type 1 and type 2 diabetes mellitus is growing worldwide and one major cause for morbidity and mortality. However, not every patient develops diabetes-related complications, but causes for the individual susceptibility are still not fully understood. As a platform to address this, we initiated the TUDID (TUebingen DIabetes Database) study, a prospective, monocentric, observational study that includes adults with diabetes mellitus who are treated in the inpatient clinic of a University Hospital in southern Germany. Besides a thorough clinical examination and extensive laboratory tests (with integrated biobanking), major study focuses are the kidneys, the eyes, the vasculature as well as cognition and mood where standardized investigations for early stages for diabetes complications are performed. Analyses of the data generated by this precise characterization of diabetes-related complications will contribute to our understanding of the development and course of such complications, and thus facilitate the implementation of tailored treatment options that can reduce the risk and severity of diabetes-related complications.

Does the Carotid Bulb Offer a Better 10-Year CVD/Stroke Risk Assessment Compared to the Common Carotid Artery? A 1516 Ultrasound Scan Study

The objectives of this study are to (1) examine the "10-year cardiovascular risk" in the common carotid artery (CCA) versus carotid bulb using an integrated calculator called "AtheroEdge Composite Risk Score 2.0" (AECRS2.0) and (2) evaluate the performance of AECRS2.0 against "conventional cardiovascular risk calculators." These objectives are met by measuring (1) image-based phenotypes and AECRS2.0 score computation and (2) performance evaluation of AECRS2.0 against 12 conventional cardiovascular risk calculators. The Asian-Indian cohort (n = 379) with type 2 diabetes mellitus (T2DM), chronic kidney disease (CKD), or hypertension were retrospectively analyzed by acquiring the 1516 carotid ultrasound scans (mean age: 55 ± 10.1 years, 67% males, ∼92% with T2DM, ∼83% with CKD [stage 1-5], and 87.5% with hypertension [stage 1-2]). The carotid bulb showed a higher 10-year cardiovascular risk compared to the CCA by 18% (P < .0001). Patients with T2DM and/or CKD also followed a similar trend. The carotid bulb demonstrated a superior risk assessment compared to CCA in patients with T2DM and/or CKD by showing: (1) ∼13% better than CCA (0.93 vs 0.82, P = .0001) and (2) ∼29% better compared with 12 types of risk conventional calculators (0.93 vs 0.72, P = .06).

Subclinical carotid atherosclerosis predicts all-cause mortality and cardiovascular events in obese patients with negative exercise echocardiography

BACKGROUND

Obesity is a major health problem due to its high prevalence. The relationship between obesity and cardiovascular disease is unclear. Some studies agree that certain conditions associated with obesity, such as physical inactivity or cardiovascular risk factors, are responsible for cardiovascular risk excess among obese people. Carotid intima-media thickness and carotid plaques (CP) have been associated with cardiovascular adverse events in healthy populations, and recent data suggest a higher prevalence of subclinical carotid atherosclerosis in obese and metabolically unhealthy patients. However, there are no studies correlating subclinical atherosclerosis and adverse events (AE) in obese subjects.

AIM

To determine the association between carotid disease and AE in obese patients with negative exercise echocardiography (EE).

METHODS

From January 1, 2006 to December 31, 2010, 2000 consecutive patients with a suspicion of coronary artery disease were submitted for EE and carotid ultrasonography. Exclusion criteria included previous vascular disease, left ventricular ejection fraction < 50%, positive EE, significant valvular heart disease and inferior to submaximal EE. An AE was defined as all-cause mortality, myocardial infarction and cerebrovascular accident. Subclinical atherosclerosis was defined as CP presence according to Manheim and the American Society of Echocardiography Consensus.

RESULTS

Of the 652 patients who fulfilled the inclusion criteria, 226 (34.7%) had body mass indexes ≥ 30 kg/m2, and 76 of them (33.6%) had CP. During a mean follow-up time of 8.2 (2.1) years, 27 AE were found (11.9%). Mean event-free survival at 1, 5 and 10 years was 99.1% (0.6), 95.1% (1.4) and 86.5% (2.7), respectively. In univariate analysis, CP predicted AE [hazard ratio (HR) 2.52, 95% confidence interval (CI) 1.17-5.46; P = 0.019]. In multivariable analysis, the presence of CP remained a predictor of AE (HR 2.26, 95%CI 1.04-4.95, P = 0.041). Other predictors identified were glomerular filtration rate (HR 0.98, 95%CI 0.96-0.99; P = 0.023), peak metabolic equivalents (HR 0.83, 95%CI 0.70-0.99, P = 0.034) and moderate mitral regurgitation (HR 5.02, 95%CI 1.42-17.75, P = 0.012).

CONCLUSION

Subclinical atherosclerosis defined by CP predicts AE in obese patients with negative EE. These patients could benefit from aggressive prevention measures.

Functional Assessment of Intermediate Vascular Disease

Interventional treatment in various vascular beds has advanced tremendously. However, there are several problems to be considered. We searched the literature and tried to analyze major parts of it. One is safety and applicability of coronary proven methods in other vascular beds. An unresolved problem is the functional assessment of intermediate lesions, as far as various target organs have quite different circulation from the coronary one and the functional tests should be modified in order to be applicable and meaningful. In the majority of the acute vascular syndromes, the culprit lesion is of intermediate size on visual assessment. On the other hand, a procedurally successfully managed high-degree stenosis is not always followed by clinical and prognostic benefit. In vascular beds, where collateral network naturally exists, the readings from the functional assessment are complicated and thus the decision for interventional treatment is even more difficult. Here come into help the functional assessment and imaging with IVUS, OCT, high-resolution MRI, and contrast enhanced CT or SPECT. The focus of the current review is on the functional assessment of intermediate stenosis in other vascular beds, unlike the coronary arteries.

Usefulness of Carotid Plaques as Predictors of Obstructive Coronary Artery Disease and Cardiovascular Events in Asymptomatic Individuals With Diabetes Mellitus

Carotid intima-media thickness (CIMT) measurement and carotid plaque detection by B-mode ultrasound are frequently used as surrogates to predict coronary artery disease (CAD). However, their systematic use in routine clinical management of asymptomatic patients with diabetes mellitus (DM) has not been studied. The aim of the study was to identify carotid parameters that predict cardiovascular events in patients with asymptomatic type 2 DM by evaluating the relation between carotid disease and CAD. This multicenter, observational, prospective study included 259 asymptomatic patients with type 2 DM followed-up for 34 months after measurement of CIMT and carotid plaque with carotid ultrasound, and CAD assessment with computed tomography coronary angiography. Statistically significant differences between patients with and without carotid plaque were found for coronary plaque >50% stenosis (59 vs 36, p = 0.02). Greater maximal CIMT was associated with an increased risk of coronary plaque >50% (odds ratio 1.21 [1.02, 1.44], p = 0.03) and >70% stenosis (odds ratio 1.23 [1.01, 1.50], p = 0.04) after adjusting for traditional risk factors. At 34-month follow-up, the occurrence of total major adverse cardiovascular event was estimated to be 7.1% (mean age 68 years, 6% male and 1.1% female) in the whole study population. The subgroup of patients with carotid plaque showed increased incidence of major adverse cardiovascular event compared with patients with no carotid plaque (p = 0.005). In conclusion, carotid plaque was a strong predictor of future cardiovascular events and may be a prognostic marker in asymptomatic patients with type 2 DM. Carotid plaque and maximal intima-media thickness were independently associated with obstructive CAD.

The coexistence of carotid and lower extremity atherosclerosis further increases cardio-cerebrovascular risk in type 2 diabetes

Background

Both carotid and lower limb atherosclerosis are associated with increased cardiovascular and cerebrovascular risks. However, it is still unclear whether the concomitant presence of carotid and lower extremity atherosclerosis further increases the cardiovascular and cerebrovascular risks. Therefore, our aim is to investigate whether the coexistence of carotid and lower extremity atherosclerosis was associated with higher cardiovascular and cerebrovascular risks in patients with type 2 diabetes.

Methods

This cross-sectional study was performed in 2830 hospitalized patients with type 2 diabetes. Based on carotid and lower limb Doppler ultrasound results, the patients were divided into three groups including 711 subjects without atherosclerosis, 999 subjects with either carotid or lower limb atherosclerosis, and 1120 subjects with both carotid and lower limb atherosclerosis. And we compared the clinical characteristics and prevalence of both cardio-cerebrovascular events (CCBVEs) and self-reported cardio- cerebrovascular diseases (CCBVDs) among the three groups.

Results

After adjusting for age, sex, and duration of diabetes, there were significant increases in the prevalence of both CCBVEs (3.8 vs. 11.8 vs. 26.4 %, p < 0.001 for trend) and self-reported CCBVDs (6.9 vs. 19.9 vs. 36.5 %, p < 0.001 for trend) across the three groups (diabetics without atherosclerosis, diabetics with either carotid or lower limb atherosclerosis, and diabetics with both carotid and lower extremity atherosclerosis). A fully adjusted logistic regression analysis also revealed that compared with those without atherosclerosis, those with either carotid or lower limb atherosclerosis had higher risk of CCBVEs (OR 1.724, 95 % CI 1.001–2.966) and self-reported CCBVDs (OR 1.705, 95 % CI 1.115–2.605), and those with concomitant presence of carotid and lower extremity atherosclerosis had the highest risk of CCBVEs (OR 2.869, 95 % CI 1.660–4.960) and self-reported CCBVDs (2.147, 95 % CI 1.388–3.320)(p < 0.001 for trend in CCBVEs and p = 0.002 for trend in CCBVDs, respectively).

Conclusions

Either carotid or lower limb atherosclerosis was obviously related to increased cardio-cerebrovascular risk in type 2 diabetes. The concomitant presence of carotid and lower extremity atherosclerosis further increased cardio-cerebrovascular risk in patients with type 2 diabetes. The combined application of carotid and lower extremity ultrasonography may help identify type 2 diabetics with higher cardio-cerebrovascular risk.

Association Between Kidney Dysfunction and Carotid Atherosclerosis in Community-Based Older Adults in China

We investigated the association between kidney dysfunction and carotid atherosclerosis in community-based older adults. This study consisted of 1257 participants, aged 55 years and older and free of cardiovascular disease. Kidney dysfunction was classified as mild, moderate, and severe (estimated glomerular filtration rate, 45-59, 30-44, and <30 mL/min/1.73 m2, respectively). We found that the mean common carotid artery intima–media thickness (CCA-IMT) progressively increased with decrement in kidney function ( P < .001). Even mild kidney dysfunction was significantly associated with CCA-IMT thickening (CCA-IMT ≥1.0 mm; odds ratio [OR] 1.52; 95% confidence interval [CI] 1.16-1.99) compared to normal kidney function. A significantly increased presence of heterogeneous plaque was observed in relation to decreased kidney function ( P for trend = .011), that is, even a mild kidney dysfunction was a potential independent risk factor for heterogeneous plaque (OR 1.43; 95% CI 1.04-1.98). Mild kidney dysfunction may be a predictor of early or accelerated carotid atherosclerosis in older adults.

Ultrasound tissue characterization of vulnerable atherosclerotic plaque

A thrombotic occlusion of the vessel fed by ruptured coronary atherosclerotic plaque may result in unstable angina, myocardial infarction or death, whereas embolization from a plaque in carotid arteries may result in transient ischemic attack or stroke. The atherosclerotic plaque prone to such clinical events is termed high-risk or vulnerable plaque, and its identification in humans before it becomes symptomatic has been elusive to date. Ultrasonic tissue characterization of the atherosclerotic plaque is possible with different techniques--such as vascular, transesophageal, and intravascular ultrasound--on a variety of arterial segments, including carotid, aorta, and coronary districts. The image analysis can be based on visual, video-densitometric or radiofrequency methods and identifies three distinct textural patterns: hypo-echoic (corresponding to lipid- and hemorrhage-rich plaque), iso- or moderately hyper-echoic (fibrotic or fibro-fatty plaque), and markedly hyperechoic with shadowing (calcific plaque). Hypoechoic or dishomogeneous plaques, with spotty microcalcification and large plaque burden, with plaque neovascularization and surface irregularities by contrast-enhanced ultrasound, are more prone to clinical complications than hyperechoic, extensively calcified, homogeneous plaques with limited plaque burden, smooth luminal plaque surface and absence of neovascularization. Plaque ultrasound morphology is important, along with plaque geometry, in determining the atherosclerotic prognostic burden in the individual patient. New quantitative methods beyond backscatter (to include speed of sound, attenuation, strain, temperature, and high order statistics) are under development to evaluate vascular tissues. Although not yet ready for widespread clinical use, tissue characterization is listed by the American Society of Echocardiography roadmap to 2020 as one of the most promising fields of application in cardiovascular ultrasound imaging, offering unique opportunities for the early detection and treatment of atherosclerotic disease.

Analysis of Carotid Ultrasound Findings on Cardiovascular Events in Patients with Coronary Artery Disease during Seven-Year Follow-Up

BACKGROUND AND OBJECTIVES

Both carotid intima-media thickness (CIMT) and carotid plaque are important factors in the primary prevention of cardiac disease. However, it is unclear which one is more important for prognosis, especially in patients with coronary artery disease (CAD).

SUBJECTS AND METHODS

In total, 1426 consecutive CAD patients, proven by angiography, were followed-up for a mean of 85 months. The study population was divided into four groups depending on the CIMT (≥0.83 mm, >95 percentile in Korea) and the presence or absence of carotid plaque.

RESULTS

Patients with carotid plaque and thick CIMT (n=237, 16.6%) had a higher prevalence of hypertension, diabetes mellitus, and dyslipidemia than those had plaque and thin CIMT (n=213, 14.9%), those without plaque and thick CIMT (n=265, 18.6%) and those without plaque and thin CIMT (n=711, 49.9%). The patients with carotid plaque and thick CIMT group had a higher cardiac mortality rate (20.7% vs. 13.1%, 9.4% and 3.9%, respectively, p<0.001) and higher major adverse cardiovascular events (MACE) including death, acute myocardial infarction, and stroke (27.8% vs. 18.8%, 15.5% and 9.3%, respectively, p<0.001) than any other groups. Multivariate Cox regression analysis showed that the presence of carotid plaque with thick CIMT had the highest hazard ratio (HR) compared to other groups (HR 2.23 vs. 1.81, 2.01) for cardiac mortality. Also, carotid plaque had a higher HR than CIMT for mortality (HR 1.56 vs. 1.37) and MACE (HR 1.54 vs. 1.36) in the total study population.

CONCLUSION

Carotid plaque is a more important prognostic factor than CIMT in patients with CAD, and adding a thick CIMT to carotid plaque increases the prognostic power for cardiac events.

Association between Ischemic Stroke and Vascular Shear Stress in the Carotid Artery

Background and Purpose

Vascular shear stress is essential for maintaining the morphology and function of endothelial cells. We hypothesized that shear stress in the internal carotid artery (ICA) may differ between patients with ischemic stroke and healthy control subjects.

Methods

ICA shear stress was calculated in 143 controls and 122 patients with ischemic stroke who had a normal ICA or an ICA with <50% stenosis. The stroke group included patients who presented with a first-ever or recurrent ischemic stroke but excluded cardioembolic stroke and uncertain etiologies. Of the 122 patients, 107 (87.7%) and 15 (12.3%) patients were categorized as first-ever and recurrent stroke, respectively.

Results

Carotid diameters were significantly larger, and both peak-systolic and end-diastolic velocities were significantly lower in patients with ischemic stroke than in controls (all p values <0.05). Mean values of peak-systolic and end-diastolic shear stress in both ICAs were significantly lower in patients with ischemic stroke in models that adjusted for age, sex, and vascular risk factors (p for trend <0.05). The ICA shear stress was lowest in patients with recurrent stroke or the subtype of small-vessel occlusion. Higher peak-systolic and end-diastolic shear stresses in both ICAs were independently and negatively associated with ischemic stroke after adjusting for potential confounders (all p values <0.05).

Conclusions

ICA shear stresses were significantly lower in patients with ischemic stroke than in control subjects. Future studies should attempt to define the causal relationship between carotid arterial shear stress and ischemic stroke.

Prediction of high-risk asymptomatic carotid plaques based on ultrasonic image features

Carotid plaques have been associated with ipsilateral neurological symptoms. High-resolution ultrasound can provide information not only on the degree of carotid artery stenosis but also on the characteristics of the arterial wall including the size and consistency of atherosclerotic plaques. The aim of this study is to determine whether the addition of ultrasonic plaque texture features to clinical features in patients with asymptomatic internal carotid artery stenosis (ACS) improves the ability to identify plaques that will produce stroke. 1121 patients with ACS have been scanned with ultrasound and followed for a mean of 4 years. It is shown that the combination of texture features based on second-order statistics spatial gray level dependence matrices (SGLDM) and clinical factors improves stroke prediction (by correctly predicting 89 out of the 108 cases that were symptomatic). Here, the best classification results of 77 ±1.8% were obtained from the use of the SGLDM texture features with support vector machine classifiers. The combination of morphological features with clinical features gave slightly worse classification results of 76 ±2.6% . These findings need to be further validated in additional prospective studies.

Carotid plaque is associated with increased cardiac mortality in patients with coronary artery disease

BACKGROUND

It is still controversial whether carotid plaque is associated with cardiovascular events in patients with coronary artery disease (CAD). The aim of the present study is to evaluate the impact of carotid plaque on long term clinical outcomes especially in patients with CAD.

METHODS

The study population consisted of 1390 consecutive patients with angiographically proven CAD. All subjects underwent carotid scanning 1 day before or after coronary angiogram and were followed up for major adverse cardiovascular events (MACE; death, myocardial infarction, stroke, revascularization, restenosis and hospitalization for heart failure) during a mean of 54.2 ± 23.9 months.

RESULTS

Patients with carotid plaque (n=433) were older, had higher prevalence of cardiovascular risk factors and acute coronary syndrome (34.2% vs. 24.6%, p<0.001) than those without carotid plaque (n=957). On univariate analysis, the presence of carotid plaque was a predictor of cardiac death, hard MACE (death, myocardial infarction and stroke) and total MACE, whereas carotid intima-media thickness (CIMT) was a predictor of total MACE. Multivariate analysis revealed that carotid plaque was associated with cardiac death (HR 6.99, 95% CI 1.88-25.95, p=0.004), hard MACE (HR 1.89, 95% CI 1.18-3.04, p=0.008) and total MACE (HR 1.47, 95% CI 1.13-1.90, p=0.004), whereas CIMT was associated only with total MACE (HR 1.39, 95% CI 1.06-1.81, p=0.017).

CONCLUSIONS

Carotid plaque is a strong predictor of future cardiac death and MACE in patients with CAD. This study suggests that carotid plaque has additional value for secondary prevention and more important prognostic factor than CIMT in patients with CAD.

Reducing morphological variability of the cervical carotid artery in serial magnetic resonance imaging using a head and neck immobilization device

PURPOSE

To evaluate how well a head and neck immobilization device performed in reducing lumen morphology variability in repeated MR imaging of the carotid artery.

MATERIALS AND METHODS

Quantitative measures of lumen and plaque characteristics may be important for longitudinal management of carotid atherosclerotic disease. However, quantitative measurements of the carotid artery are limited by their dependence on patient positioning, which can be quite variable. We created a head and neck immobilization device to reduce the variability of patient positioning during MR imaging of the carotid artery. In this article we describe the design and use of the immobilization device and assess how well its use reduced variability in vascular orientation and measurements of the carotid lumen cross-sectional area. Evaluation was based on 15 subjects who were repeatedly imaged without the immobilization device and 14 subjects who were repeatedly imaged with the device.

RESULTS

Use of the immobilization device decreased the orientation variability from 9.1 degrees to 5.3 degrees (P = 0.0006) and the variability (defined as the standard deviation divided by the mean) of the cross-sectional area decreased from 0.24 to 0.18 (P = 0.04).

CONCLUSION

Using the immobilization device effectively reduces variability in repeated imaging of the carotid arteries.