Carotid artery calcification score and its association with cognitive impairment

Calcified carotid artery atheromas in individuals with cognitive dysfunction

OBJECTIVE

The aim of this case-control study was to investigate whether cognitively impaired individuals have a higher burden of calcified carotid artery atheroma (CCAA) than controls without cognitive impairment.

MATERIAL AND METHODS

The study included 154 cases with Alzheimer's disease (n = 52), mild cognitive impairment (n = 51), or subjective cognitive decline (n = 51) diagnosed at a university memory clinic. Seventy-six cognitively healthy controls were sampled through the Swedish population register. All participants underwent clinical oral and panoramic radiographic examinations. Two oral and maxillofacial radiologists performed blinded analyses of the panoramic radiographs for signs of CCAA, which was registered as absent or present and, if present, unilateral or bilateral. Consensus assessment was used for all statistical analyses.

RESULTS

CCAA was common (40%) in this middle-aged and older Swedish population. We found no differences in the prevalence of CCAA between cases and controls (40% vs. 42%).

CONCLUSION

Cognitively impaired patients do not have a higher burden of CCAA than matched controls without cognitive impairment.

Associations between carotid atherosclerotic plaque characteristics determined by magnetic resonance imaging and improvement of cognition in patients undergoing carotid endarterectomy

BACKGROUND

To determine the predictive value of carotid plaque characteristics for the improvement of cognition in patients with moderate-to-severe carotid stenosis after carotid endarterectomy (CEA), using vessel wall magnetic resonance imaging (MRI).

METHODS

This was a prospective cohort study. Patients with unilateral, moderate-to-severe carotid stenosis referred to the Peking University Third Hospital for CEA were prospectively recruited and underwent carotid vessel wall MRI within 1 week before CEA. We performed Montreal Cognitive Assessment (MoCA) within 1 week before and 3-4 days after CEA. The morphological and compositional characteristics of carotid plaques on MRI were evaluated. Improvement of cognition was defined as >10% increase of the total MoCA score after CEA compared with baseline. Carotid plaque characteristics were compared between patients with and without cognitive improvement.

RESULTS

In total, 105 patients (91 males; mean age, 65.5±8.4 years) were included. The volume {48.0 [interquartile range (IQR), 21.0 to 91.6] vs. 16.3 (IQR, 8.1 to 53.1) mm3; P=0.005} and cumulative slice [4.0 (IQR, 3.0 to 7.0) vs. 3.0 (IQR, 2.0 to 5.0); P=0.019] of carotid calcification, and maximum percentage of calcification area [13.1% (IQR, 6.0% to 19.8%) vs. 6.2% (IQR, 3.7% to 10.8%); P=0.004] were significantly smaller in participants with cognitive improvement compared to those without. Univariate logistic regression analysis showed that volume [odds ratio (OR) =0.994; 95% confidence interval (CI): 0.989 to 1.000; P=0.043] and cumulative slice (OR =0.823; 95% CI: 0.698 to 0.970; P=0.020) of carotid calcification, and maximum percentage of calcification area (OR =0.949; 95% CI: 0.909 to 0.991; P=0.018) were significantly correlated with cognitive improvement. After adjusting for confounding factors, these associations remained statistically or marginally significant (volume: OR =0.994; 95% CI: 0.988 to 1.000; P=0.057; maximum percentage of calcification area: OR =0.937; 95% CI: 0.890 to 0.987; P=0.014; and cumulative slice: OR =0.791; 95% CI: 0.646 to 0.967; P=0.022). No significant associations were found between other plaque characteristics and cognitive improvement (all P>0.05).

CONCLUSIONS

More than half of the participants with unilateral, moderate-to-severe carotid atherosclerotic stenosis had cognitive improvement. The size of calcification might be an effective indicator of cognitive improvement after CEA.

Carotid Artery Calcification: What We Know So Far

Carotid artery calcification (CAC) is a well-known marker of atherosclerosis and is linked to a high rate of morbidity and mortality. CAC is divided into two types: intimal and medial calcifications, each with its own set of risk factors. Vascular calcification is now understood to be an active, enzymatically regulated process involving dystrophic calcification and endothelial dysfunction at an early stage. This causes a pathogenic inflammatory response, resulting in calcium phosphate deposition in the form of microcalcifications, which causes plaque formation, ultimately becoming unstable with sequelae of complications. If the inflammation goes away, hydroxyapatite crystal formation takes over, resulting in macro-calcifications that help to keep the plaque stable. As CAC can be asymptomatic, it is critical to identify it early using diagnostic imaging. The carotid artery calcification score is calculated using computed tomography angiography (CTA), which is a confirmatory test that enables the examination of plaque composition and computation of the carotid artery calcification score. Magnetic resonance angiography (MRA), which is sensitive as CTA, duplex ultrasound (DUS), positron emission tomography, and computed tomography (PET-CT) imaging with (18) F-Sodium Fluoride, and Optical Coherence Tomography (OCT) are some of the other diagnostic imaging modalities used. The current therapeutic method starts with the best medical care and is advised for all CAC patients. Carotid endarterectomy and carotid stenting are two treatment options that have mixed results in terms of effectiveness and safety. When patient age and anatomy, operator expertise, and surgical risk are all considered, the agreement is that both techniques are equally beneficial.

Impact of carotid stenosis on cerebral hemodynamic failure and cognitive impairment progression: a narrative review

Carotid atherosclerosis has a relevant impact on cerebral blood flow regulation. There is accruing evidence that hemodynamic impairment related to the presence of a significant carotid lumen narrowing may predispose to the development of cerebral dysfunctions, including a reduction in cognitive abilities. In the last years an increasing number of findings showed that carotid stenosis did contribute to cognitive impairment not only in relation to the occurrence of cerebral ischemic lesions, but also as an independent risk factor. The principal mechanisms involved are chronic hypoperfusion, microembolization and cerebrovascular reactivity impairment. Moreover, more recent studies showed alterations of regional functional connectivity. In this narrative review, we analyzed the relationships between carotid stenosis, cerebral hemodynamic derangement and cognitive impairment onset and progression, and underlined that cognitive impairment is the final result of the complex interaction between different elements, including also collateral circulation, cerebral hemodynamic status, brain connectivity and pro-inflammatory state. Further, therapeutic approaches, with a specific focus on vascular risk factors correction and on the effectiveness of surgical or endovascular interventions were discussed. We particularly focused our attention on the concept of “asymptomatic carotid stenosis”, and how could a cognitive impairment improve after an intervention, and how this could change the indications to surgical approach. Larger studies and randomized controlled trials are urgently required to better define time, characteristics and effectiveness of both medical and surgical/endovascular approaches.

Hypothesis of "stroke-stop" formula: a tool for risk index determination in development of acute cerebrovascular disease in asymptomatic individuals with carotid stenosis

Background

Extracranial carotid artery disease is considered a risk factor for developing acute cerebrovascular diseases. The paper suggests the “Stroke-Stop” formula as hypothesis for the determination of the risk of developing stroke in asymptomatic individuals with carotid stenosis. The formula is based on a mathematical calculation of the major risk factors for stroke: the degree of ICA (internal carotid artery) stenosis, the morphological structure of the atherosclerotic plaque and the level of lipoprotein-associated phospholipase A2 (Lp-PLA2) concentration.

Methods

The cross sectional study included 70 patients with atherosclerotic ICA stenosis. Among vascular inflammatory markers, Lp-PLA2 was determined with concentration 252.7–328.6 mg/l. The obtained results were evaluated using descriptive statistics (the frequency, percentage ratio) as well as the one-way analysis of variance (ANOVA) and chi-square test.

Results

The risk of stroke development is eminently increasing with the progression of ICA stenosis and elevation of Lp-PLA2 levels. In patients with echolucent plaque, the risk of stroke development was significantly higher in correlation with patients with echogenic plaque. Based on calculations using “Stroke-Stop” formula, three main groups were generated: low (< 70 points), medium (70–100 points) and high (> 100 points) risk of stroke development.

Conclusions

Hypothesis of “Stroke-Stop” formula is proposed for better selection of patients who should be indicated for surgical treatment and will be evaluated in prospective study. In order to verify this hypothesis, we plan to do prospective study using “Stroke-Stop” formula for ipsilateral annual stroke rate in asymptomatic individuals with carotid stenosis who receive conservative therapy.

Stenosis, ulceration of the atherosclerotic plaque and Lp-PLA2 concentration are calculated

3 groups of stroke risk development were set (low, medium and high)

Proposed formula form personalized approach to the diagnosis and prevention of stroke

Cerebral Hypoxia: Its Role in Age-Related Chronic and Acute Cognitive Dysfunction

Postoperative cognitive dysfunction (POCD) has been reported with widely varying frequency but appears to be strongly associated with aging. Outside of the surgical arena, chronic and acute cerebral hypoxia may exist as a result of respiratory, cardiovascular, or anemic conditions. Hypoxia has been extensively implicated in cognitive impairment. Furthermore, disease states associated with hypoxia both accompany and progress with aging. Perioperative cerebral hypoxia is likely underdiagnosed, and its contribution to POCD is underappreciated. Herein, we discuss the various disease processes and forms in which hypoxia may contribute to POCD. Furthermore, we outline hypoxia-related mechanisms, such as hypoxia-inducible factor activation, cerebral ischemia, cerebrovascular reserve, excitotoxicity, and neuroinflammation, which may contribute to cognitive impairment and how these mechanisms interact with aging. Finally, we discuss opportunities to prevent and manage POCD related to hypoxia.

Editor's Choice - Asymptomatic Carotid Stenosis and Cognitive Impairment: A Systematic Review

OBJECTIVE

The aim was to evaluate the relationship between asymptomatic carotid stenosis (ACS) of any severity and cognitive impairment and to determine whether there is evidence supporting an aetiological role for ACS in the pathophysiology of cognitive impairment.

DATA SOURCES

PubMed/Medline, Embase, Scopus, and the Cochrane library.

REVIEW METHODS

This was a systematic review (35 cross sectional or longitudinal studies) RESULTS: Study heterogeneity confounded data interpretation, largely because of no standardisation regarding cognitive testing. In the 30 cross sectional and six longitudinal studies (one included both), 33/35 (94%) reported an association between any degree of ACS and one or more tests of impaired cognitive function (20 reported one to three tests with poorer cognition; 11 reported four to six tests with poorer cognition, while three studies reported seven or more tests with poorer cognition). There was no evidence that ACS caused cognitive impairment via silent cortical infarction, or via involvement in the pathophysiology of lacunar infarction or white matter hyperintensities. However, nine of 10 studies evaluating cerebral vascular reserve (CVR) reported that ACS patients with impaired CVR were significantly more likely to have cognitive impairment and that impaired CVR was associated with worsening cognition over time. Patients with severe ACS but normal CVR had cognitive scores similar to controls.

CONCLUSION

Notwithstanding significant heterogeneity within the constituent studies, which compromised overall interpretation, 94% of studies reported an association between ACS and one or more tests of cognitive impairment. However, "significant association" does not automatically imply an aetiological relationship. At present, there is no clear evidence that ACS causes cognitive impairment via silent cortical infarction (but very few studies have addressed this question) and no evidence of ACS involvement in the pathophysiology of white matter hyperintensities or lacunar infarction. There is, however, better evidence that patients with severe ACS and impaired CVR are more likely to have cognitive impairment and to suffer further cognitive decline with time.

Doppler Ultrasound Monitoring of Echogenicity in Asymptomatic Subcritical Carotid Stenosis and Assessment of Response to Oral Supplementation of Vitamin K2 (PLAK2 Randomized Controlled Trial)

BACKGROUND

Plaque composition may predict the evolution of carotid artery stenosis rather than its sole extent. The grey scale median (GSM) value is a reproducible and standardized value to report plaque echogenicity as an indirect measure of its composition. We monitored plaque composition in asymptomatic subcritical carotid stenosis and evaluated the effect of an oral modulating calcification factor (vitamin K2).

METHODS

Carotid plaque composition was assessed by GSM value. Monitoring the effects of standard therapy (acetylsalicylic acid and low-medium dosage statin) (acetylsalicylic acid (ASA) arm) or standard therapy plus vitamins K2 oral supplementation (ASA + K2 arm) over a 12 months period was conducted using an ultrasound scan in a prospective, open-label, randomized controlled trial (PLAK2).

RESULTS

Sixty patients on low-medium dosage statin therapy were enrolled and randomized (30 per arm) to either ASA + K2 or ASA alone. Thirty-seven patients (61.6%) showed at 12 months a stable plaque with a mean increase in the GSM value in respect to the baseline of 2.6% with no differences between the two study arms (p = 0.66). Fifteen patients (25%) showed an 8% GSM value reduction respect the baseline with no differences between the two study arms (p = 0.99). At multivariable analysis, the adjusted mean (95% confidence interval) GSM change per month from baseline was greater in the ASA + K2 arm (-0.55 points, p = 0.048) compared to ASA alone (-0.18 points, p = 0.529).

CONCLUSIONS

Carotid plaque composition monitoring through GSM value represents a laborious procedure. Although its use may not be applied to everyday practice, a specific application consists in evaluating the effect of pharmacological therapy on plaque composition. This 12 months randomized trial showed that the majority of subcritical asymptomatic carotid plaque on treatment with low-medium dosage statin presented a stable or increased echogenicity. Although vitamin K2 beyond standard therapy did not determine a significant change in plaque composition, for those who presented with GSM reduction it did enhance a GSM monthly decline.

Risk Factors for Residual Stenosis After Carotid Artery Stenting

Background and purpose: Stent residual stenosis is an independent risk factor for restenosis after stenting. This study aimed to analyze the factors influencing residual stenosis after carotid artery stenting (CAS). Methods: A total of 570 patients who underwent CAS with 159 closed-loop stents (CLS) and 411 open-loop stents (OLS) from January 2013 to January 2016 were retrospectively enrolled in this study. Carotid stenosis location in the common carotid artery or in internal carotid artery, plaque size, and features (regular or irregular morphology; with or without calcification), degree of carotid artery stenosis, and stent expansion rate were detected by carotid duplex ultrasonography. Residual stenosis was defined as a stenosis rate ≥30% after CAS, as detected by digital subtraction angiography. A logistic regression analysis was used to analyze residual stenosis risk factors. Results: The overall incidence of residual stenosis was 22.8% (130/570 stents). The incidence of residual stenosis in the CLS group was higher than that in the OLS group (29.5 vs. 20.2%, χ² = 5.71, P = 0.017). The logistic regression analysis showed that CLS [odds ratio (OR), 1.933; 95% confidence interval (CI), 1.009-3.702], irregular plaques (OR, 4.237; 95% CI, 2.391-7.742), and plaques with calcification (OR, 2.370; 95% CI, 1.337-4.199) were independent risk factors for residual stenosis after CAS. In addition, a high radial expansion rate of stent was a protective factor for residual stenosis (OR, 0.171; 95% CI, 0.123-0.238). The stenosis location and stent length did not impact the occurrence of residual stenosis. After 1-year follow-up, the incidence of restenosis in the residual stenosis group was higher than that in the group without residual stenosis (13.1 vs. 2.0%, χ² = 28.05, P < 0.001). Conclusions: The findings of this study suggest that plaque morphology, echo characteristics (with calcification), and stents type influence residual stenosis.