Ultrasound and angiography in the selection of patients for carotid endarterectomy

Validation of Risk Prediction Models to Detect Asymptomatic Carotid Stenosis

Background Significant asymptomatic carotid stenosis (ACS) is associated with higher risk of strokes. While the prevalence of moderate and severe ACS is low in the general population, prediction models may allow identification of individuals at increased risk, thereby enabling targeted screening. We identified established prediction models for ACS and externally validated them in a large screening population. Methods and Results Prediction models for prevalent cases with ≥50% ACS were identified in a systematic review (975 studies reviewed and 6 prediction models identified [3 for moderate and 3 for severe ACS]) and then validated using data from 596 469 individuals who attended commercial vascular screening clinics in the United States and United Kingdom. We assessed discrimination and calibration. In the validation cohort, 11 178 (1.87%) participants had ≥50% ACS and 2033 (0.34%) had ≥70% ACS. The best model included age, sex, smoking, hypertension, hypercholesterolemia, diabetes mellitus, vascular and cerebrovascular disease, measured blood pressure, and blood lipids. The area under the receiver operating characteristic curve for this model was 0.75 (95% CI, 0.74-0.75) for ≥50% ACS and 0.78 (95% CI, 0.77-0.79) for ≥70% ACS. The prevalence of ≥50% ACS in the highest decile of risk was 6.51%, and 1.42% for ≥70% ACS. Targeted screening of the 10% highest risk identified 35% of cases with ≥50% ACS and 42% of cases with ≥70% ACS. Conclusions Individuals at high risk of significant ACS can be selected reliably using a prediction model. The best-performing prediction models identified over one third of all cases by targeted screening of individuals in the highest decile of risk only.

Bioinformatics Study on Serum Triglyceride Levels for Analysis of a Potential Risk Factor Affecting Blood Pressure Variability

Objective:

The purpose of this study was to establish whether Triglycerides (TGs) are related to Blood Pressure (BP) variability and whether controlling TG levels leads to better BP variability management and prevents Cardiovascular Disease (CVD).

Methods:

In this study, we enrolled 106 hypertensive patients and 80 non-hypertensive patients. Pearson correlation and partial correlation analyses were used to define the relationships between TG levels and BP variability in all subjects. Patients with hypertension were divided into two subgroups according to TG level: Group A (TG<1.7 mmol/L) and Group B (TG>=1.7 mmol/L). The heterogeneity between the two subgroups was compared using t tests and covariance analysis.

Results:

TG levels and BP variability were significantly different between the hypertensive and non-hypertensive patients. Two-tailed Pearson correlation tests showed that TG levels are positively associated with many BP variability measures in all subjects. After reducing other confounding factors, the partial correlation analysis revealed that TG levels are still related to the Standard Deviation (SD), Coefficient of Variation (CV) of nighttime systolic blood pressure and CV of nighttime diastolic blood pressure, respectively (each p<0.05). In the subgroups, group A had a lower SD of nighttime Systolic Blood Pressure (SBP_night_SD; 11.39±3.80 and 13.39±4.16, p=0.011), CV of nighttime systolic blood pressure (SBP_night_CV; 0.09±0.03 and 0.11±0.03, p=0.014) and average real variability of nighttime systolic blood pressure (SBP_night_ARV; 10.99±3.98 and 12.6±3.95, p=0.024) compared with group B, even after adjusting for age and other lipid indicators.

Conclusion:

TG levels are significantly associated with BP variability and hypertriglyceridemia, which affects blood pressure variability before causing target organ damage.

Ultrasound assessment of carotid arteries: Current concepts, methodologies, diagnostic criteria, and technological advancements

Following cardiac disease and cancer, stroke continues to be the third leading cause of death and disability due to chronic disease in the developed world. Appropriate screening tools are integral to early detection and prevention of major cardiovascular events. In a carotid artery, the presence of increased intima-media thickness, plaque, or stenosis is associated with increased risk of a transient ischemic attack or a stroke. Carotid artery ultrasound remains a long-standing and reliable tool in the current armamentarium of diagnostic modalities used to assess vascular morbidity at an early stage. The procedure has, over the last two decades, undergone considerable upgrades in technology, approach, and utility. This review examines in detail the current state and usage of this integrally important means of extracranial cerebrovascular assessment.

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.

Endovascular treatment of carotid occlusive disease

Carotid occlusive disease is one of several etiologic factors for stroke. Of all strokes, an estimated 88% are ischemic in nature. Less than 20% of these are caused by atheroma in the carotid bifurcation. Traditionally, carotid artery stenosis has been treated with carotid endarterectomy (CEA); however, carotid artery balloon angioplasty and stent placement has enjoyed significant technological advances over the last decade and can now offer a comparable treatment alternative to CEA. In this review, the authors concentrate their discussion on the treatment of carotid atherosclerotic disease with particular attention on the endovascular treatment.

Accuracy of angiography and Doppler ultrasonography in the detection of carotid stenosis: a histopathological study of 123 cases

BACKGROUND

A prospective study was performed comparing the accuracy of digital subtraction angiography (DSA) and Doppler ultrasonography (DUS) stenosis findings with measurements on histological specimens.

METHOD

DSA and DUS were used to evaluate carotid stenosis and were compared with measurements on histological specimens. Intact carotid plaques from 123 cases were removed in one piece during surgery. The specimens were histologically processed and examined in transverse sections. The smallest inner and correlating outer diameters were measured and the extent of stenosis was calculated. Carotid artery stenoses were compared and statistics done. Specimens in symptomatic cases were divided into 3 groups: stenosis 30-49% (Group 1), stenosis 50-69% (Group 2) and stenosis 70-99% (Group 3). Specimens in asymptomatic cases were divided into two groups: stenosis<or=59% (Group A) and stenosis>or=60% (Group B).

FINDINGS

Wilcoxon paired tests revealed significant differences between DSA, DUS and measurements on histological specimens. In severe stenoses only, no significant difference was observed between stenosis measurement according to the European Carotid Surgery Trial (ECST) angiography methodology and measurements on histological specimens. The most pronounced differences were found between angiography methodology of the North American Symptomatic Carotid Endarterectomy Trial (NASCET) and measurements on histological specimens. When investigating how often preoperative measurement classified stenosis into the same Group of stenoses as postoperative measurement, DUS was the most accurate diagnostic tool.

CONCLUSIONS

This study confirmed our previous results, i.e., angiography underestimates the degree of carotid artery stenosis. DUS seems to be more accurate in classifying stenoses into different groups to the extent of narrowing of the carotid arteries. These results make the position of angiography in diagnostic algorithm of carotid stenoses investigations even more questionable.

Risk factors for periprocedural complications in carotid artery stenting without filter protection

INTRODUCTION

In high-grade stenosis, carotid artery stenting (CAS) may be chosen as an alternative to carotid surgery. Ischemic periprocedural complications may be documented best with diffusion-weighted MRI (DWMRI). In this prospective study serial DW-MRI and color-coded duplex sonography (CCDS) were used to identify carotid stenosis, which is associated with an increased risk of ischemic events due to CAS.

METHODS

High resolution DW-MRI were performed in 74 out of 77 patients before and after CAS. All MRI scans were analyzed in a blinded manner. With CCDS each carotid stenosis was evaluated according to the grade, length, echo properties and plaque surface.

RESULTS

In 42 out of 74 patients (56.8 %) a total of 188 new procedure- related DWI-lesions could be detected, while in 32 patients MRI-controls remained normal. Of the lesions 79.25 % had a size < 1 cm. In one major and two minor strokes due to CAS (total complication rate 3.9 %) corresponding territorial infarcts could be demonstrated. A highly significant correlation was found between the length of the stenosis and the incidence of new DWI-lesions (p = 0.0141). In contrast, neither the grade of ICA stenosis nor the sonographic plaque morphology or plaque surface correlated with the number of DWI-lesion in postinterventional scans.

CONCLUSIONS

The length-and not the degree-of an ICA stenosis seems to be the most decisive sonographic factor for estimating the periprocedural risk of embolism. DWI-lesions are much more frequent than clinical complications and may represent an important surrogate marker for improving the techniques of carotid artery stenting, especially comparing the benefit of different mechanical protection devices.