Nardi, Valentina

Abstract Cardiovascular disease remains a prominent cause of disability and premature death worldwide. Within this spectrum, carotid artery atherosclerosis is a complex and multifaceted condition, and a prominent precursor of acute ischaemic stroke and other cardiovascular events. The intricate interplay among inflammation, oxidative stress, endothelial dysfunction, lipid metabolism, and immune responses participates in the development of lesions, leading to luminal stenosis and potential plaque instability. Even non-stenotic plaques can precipitate a sudden cerebrovascular event, regardless of the degree of luminal encroachment. In this context, carotid imaging modalities have proved their efficacy in providing in vivo characterization of plaque features, contributing substantially to patient risk stratification and clinical management. This review emphasizes the importance of identifying high-risk individuals by use of current imaging modalities, biomarkers, and risk stratification tools. Such approaches inform early intervention and the implementation of personalized therapeutic strategies, ultimately enhancing patient outcomes in the realm of cardiovascular disease management.

Introduction: Atrial fibrillation (AF) is prevalent in patients with atherosclerotic coronary and carotid artery disease and is associated with elevated plasma inflammatory markers, such as Interleukin (IL)-6. In carotid artery atherosclerosis, macrophages are considered a local marker of inflammation. Hypothesis: We hypothesize that AF is independently associated with carotid plaque inflammation. Aims: In patients undergoing carotid endarterectomy (CEA), we aimed to determine whether carotid plaques inflammation is associated with AF. Approach: In this prospective cohort study, consecutive patients with carotid artery disease undergoing CEA were enrolled. From the plaques removed during surgery, fixed in formalin and embedded in paraffin blocks, sections were stained with antibodies against CD68 to detect macrophages (Fig.1A) . Digital copies of the slides were created by Motic Easy Scan and histologically annotated with QuPath. The percentage of CD68+ cells was defined as (CD68+ positive cells/total nuclei) x 100. Flash-frozen plaque segments were analyzed by ELISA for IL-6 concentration. Baseline demographics and clinical data, including AF diagnosis, were extracted from the electronic health records. Results: A total of 106 patients undergoing CEA, with a median age of 73 [67-78] years and comprising 83 (78.3%) males, were included in the study. AF was diagnosed prior to CEA in 13 (12.3%) patients. Univariate logistic regression showed that plaque CD68+ cell content was associated with AF (OR 1.048 [95% CI 1.010 – 1.088]; p = 0.013). Additionally, in Mann-Whitney test IL-6 levels were significantly over twofold higher in plaques of patients with AF compared to those without AF (82.4 [64.9-111.7] pg/mg vs 37.0 [18.4-93.3] pg/mg; p=0.020) (Fig. 1B) . Conclusions: The current study demonstrates an association between carotid atherosclerotic plaque macrophage content, IL6 levels and AF, supporting the role of inflammation in the pathogenesis of AF in these patients. Further studies are needed to determine the potential of plaque inflammation as a therapeutic target in AF.

Positive remodeling (PR) is an atherosclerotic plaque feature defined as an increase in arterial caliber at the level of an atheroma, in response to increasing plaque burden. The mechanisms that lead to its formation are incompletely understood, but its role in coronary atherosclerosis has major clinical implications. Indeed, plaques with PR have elevated risk of provoking acute cardiac events. Hence, PR figures among the high-risk plaque features that cardiac imaging studies should report. This review aims to provide an overview of the current literature on coronary PR. It outlines the pathophysiology of PR, the different techniques used to assess its presence, and the imaging findings associated to PR, on both noninvasive and invasive studies. This review also summarizes clinical observations, trials, and studies, focused on the impact of PR on clinical outcome.

Abstract Background Patients with carotid artery disease undergoing carotid endarterectomy (CEA) appear to be at high risk of all-cause mortality during their follow-up. However, the possible predictors of this adverse outcome are not elucidated yet. Purpose We aimed to test cardiovascular (CV) risk factors as possible predictors of all-cause mortality in patients undergoing CEA and to determine whether there is a difference between the mortality rate of our study cohort and the general population. We hypothesize that CEA-treated patients have a higher mortality rate during follow-up after surgery than the general population, which is not related to the presence of CV risk factors. Methods We prospectively enrolled and followed up patients undergoing CEA. Univariate and multivariable Cox regression were performed to test whether common CV risk factors (demographics, laboratory values, comorbidities, and events before CEA) were predictive of all-cause mortality. We then compared the standardized mortality ratio (SMR) of our population and the age-sex-matched Minnesota (MN) general population at 5,10, and 21 years of follow-up after CEA. Results A total of 710 patients were followed for a median of 7.1 [2.9-11.9] years after CEA. Mortality occurred in 198 (27.0%) patients during the follow-up. The median time to event was 11.0 [10.0-12.0] years. Age was the only predictor of all-cause mortality in CEA-treated patients in multivariable models adjusted for known CV risk factors (Model 1: HR 1.03 [95%CI 1.01-1.06]; p=0.004; Model 2: HR 1.02 [95%CI 1.00-1.04]; p=0.023) (Table 1). However, the CEA-treated group had a higher mortality rate than would have been expected in the MN population (log-rank p<0.001) (Fig.1A). Compared to the MN population, at 5 years of follow-up only patients <60 years old had a higher SMR (4.53 [1.95-8.92]; p=0.001), whereas, at 10 years and 21 years of follow-up, our study population had a higher mortality rate at any age (Fig.1B). Conclusions The elevated mortality risk post-CEA in our cohort cannot be solely attributed to chronological aging. The underlying process of atherosclerosis likely contributes to all-cause mortality, and plaque characteristics may offer additional insight into the risk stratification of this patient group.All cause mortality predictors after CEAStudy population vs. MN population SMR

Abstract Background Patients with carotid artery disease undergoing carotid endarterectomy (CEA) have a high risk of experiencing Major Adverse Cardiovascular Events (MACE) after surgery. The occurrence of MACE in CEA-treated patients is not predicted by common cardiovascular (CV) risk factors. Purpose We aimed to identify the association between plasma and plaque inflammatory cytokines and the incidence of MACE in the follow-up after CEA. We hypothesized that MACE is related to a higher level of circulating inflammatory cytokines at the time of surgery. Methods We prospectively enrolled patients with carotid artery disease undergoing CEA. Plasma and carotid plaques were collected during the surgery. Inflammatory cytokines (MCP-1/CCL2, IL-8/CXCL8, IFN-gamma, IL-10, IL-1beta/IL-1F2, IL-6, PDGF-AA, PDGF-AB/BB, TNF-alpha, VEGF) were measured in plasma and tissue homogenates using a customized 10-plex Luminex assay. Baseline demographics and clinical data for all the patients were extracted from electronic health records. MACE after CEA was defined as a composite measure of nonfatal cardiac events such as myocardial infarction with or without revascularization, cerebrovascular events (ischemic stroke, TIA, and amaurosis fugax), and all-cause mortality. Results Of 107 patients who underwent CEA with a median age of 73 (67-78) years, 57 (53.2%) experienced MACE during a median follow-up of 5.2 [2.2-9.3] years: 23 (40.3%) cardiac events, 9 (15.7%) CVA, and 25 (43.8%) all-cause mortality. Plaque cytokines levels did not differ between the groups with and without MACE in the follow-up after CEA. Instead, plasma cytokines were associated with MACE in the follow-up after CEA, as summarized in Figure 1. In the logistic regression analysis, plasma levels of MCP-1/CCL2, IFN-gamma, and TNF-alpha were independent predictors of MACE in follow-up post-CEA in univariate and multivariable models adjusted for CV risk factors such as age, BMI, systolic and diastolic blood pressure, low-density lipoprotein, high-density lipoprotein, and glucose level: MCP1/CCL2 (HR 1.009 [1.002-1.015]; p=0.007), IFN-gamma (HR 1.368 [1.014-1.845]; p=0.040), and TNF-alpha (HR 1.121 [1.022-1.228]; p=0.015) (Table 1). Conclusions Plasma levels of CCL2, IFN-gamma, and TNF-alpha are associated with the high incidence of MACE in the follow-up after CEA, indicating that these are potential biomarkers of MACE in this patient population and potential therapeutic targets in patients' progression of systemic atherosclerosis.Plasma cytokines and MACE after CEACytokines logistic regression analysis

Abstract Background One of the main features of vulnerability in atherosclerotic carotid plaques is intraplaque hemorrhage (IPH), which is related to a higher incidence of cerebrovascular events in patients with carotid artery disease. Additionally, inflammation plays a pivotal role in the progression of atherosclerotic disease. Purpose We aimed to determine plasma and tissue levels of inflammatory cytokines in patients with carotid artery disease hypothesizing that plaques with IPH are characterized by the presence of a more inflamed environment. Methods We retrospectively enrolled 104 consecutive patients undergoing carotid endarterectomy (CEA) with symptomatic (ischemic stroke, TIA, amaurosis fugax) or asymptomatic ipsilateral carotid artery disease. Plasma and carotid plaque specimens were collected at CEA. The tissue samples were stained with H&E to identify IPH and classified as specimens with and without IPH. Frozen homogenates of both plasma and tissue were analyzed using a customized 10-plex Luminex assay to determine the levels of inflammatory cytokines such as MCP-1/CCL2, IL-8/CXCL8, IFN-gamma, IL-10, IL-1beta/IL-1F2, IL-6, PDGF-AA, PDGF-AB/BB, TNF-alpha, and VEGF. Results IPH was identified in 53 patients (51.0 %). Cytokine levels in plasma and tissue from patients with and without IPH are reported in Table 1. In the univariate logistic regression MCP-1/CCL2, IL-8/CXCL8, IFN-gamma, IL-10, IL6, PDGF-AA, and PDGF-AB/BB were associated with IPH (Table 2). In the multivariate logistic regression, IL-6 was an independent predictor of IPH (HR 1.026 [95% CI 1.005-1.047]; p=0.014) after adjusting for cardiovascular risk factors such as age, BMI, sex, hypertension, diabetes mellitus, hyperlipidemia, ipsilateral carotid stenosis %. Conclusions Carotid plaques with IPH have an elevated inflammatory burden, potentially impacting adverse outcomes in this patient cohort. The local inflammatory cytokines in carotid plaques with IPH might serve as biomarkers and therapeutic targets in patients with carotid artery disease.

BACKGROUND: This study aimed to develop and validate a computed tomography angiography based machine learning model that uses plaque composition data and degree of carotid stenosis to detect symptomatic carotid plaques in patients with carotid atherosclerosis. METHODS: The machine learning based model was trained using degree of stenosis and the volumes of 13 computed tomography angiography derived intracarotid plaque subcomponents (eg, lipid, intraplaque hemorrhage, calcium) to identify plaques associated with cerebrovascular events. The model was internally validated through repeated 10-fold cross-validation and tested on a dedicated testing cohort according to discrimination and calibration. RESULTS: This retrospective, single-center study evaluated computed tomography angiography scans of 268 patients with both symptomatic and asymptomatic carotid atherosclerosis (163 for the derivation set and 106 for the testing set) performed between March 2013 and October 2019. The area-under-receiver-operating characteristics curve by machine learning on the testing cohort (0.89) was significantly higher than the areas under the curve of traditional logit analysis based on the degree of stenosis (0.51, P <0.001), presence of intraplaque hemorrhage (0.69, P <0.001), and plaque composition (0.78, P <0.001), respectively. Comparable performance was obtained on internal validation. The identified plaque components and associated cutoff values that were significantly associated with a higher likelihood of symptomatic status after adjustment were the ratio of intraplaque hemorrhage to lipid volume (≥50%, 38.5 [10.1–205.1]; odds ratio, 95% CI) and percentage of intraplaque hemorrhage volume (≥10%, 18.5 [5.7–69.4]; odds ratio, 95% CI). CONCLUSIONS: This study presented an interpretable machine learning model that accurately identifies symptomatic carotid plaques using computed tomography angiography derived plaque composition features, aiding clinical decision-making.

Introduction In the current paper, the “carotid artery calcium score” method is presented with the target to offer a metric method to quantify the amount of calcification in the carotid artery. Model and Definition The Volume of Interest (VOI) should be extracted and those voxels, with a Hounsfield Unit (HU) value ≥130, should be considered. The total weight value is determined by calculating the sum of the HU attenuation values of all voxels with values ≥130 HU. This value should be multiplied by the conversion factor (“or voxel size”) and divided by a weighting factor, the attenuation threshold to consider a voxel as calcified (and therefore 130 HU): this equation determines the Carotid Artery Calcium Score (CACS). Results In order to provide the demonstration of the potential feasibility of the model, the CACS was calculated in 131 subjects (94 males; mean age 72.7 years) for 235 carotid arteries (in 27 subjects, unilateral plaque was present) considered. The CACS value ranged from 0.67 to 11716. A statistically significant correlation was found (rho value = 0.663, p value = .0001) between the CACS in the right and left carotid plaques. Moreover, a statistically significant correlation between the age and the total CACS was present (rho value = 0.244, p value = .005), whereas no statistically significant difference was found in the distribution of CACS by gender ( p = .148). The CACS was also tested at baseline and after contrast and no statistically significant difference was found. Conclusion In conclusion, this method is of easy application, and it weights at the same time the volume and the degree of calcification in a unique parameter. This method needs to be tested to verify its potential utility, similar to the coronary artery calcium score, for the risk stratification of the occurrence of cerebrovascular events of the anterior circulation. Further studies using this new diagnostic tool to determine the prognostic value of carotid calcium quantification are needed.

Coronary artery calcification (CAC) accompanies the development of advanced atherosclerosis. Its role in atherosclerosis holds great interest because the presence and burden of coronary calcification provide direct evidence of the presence and extent of coronary artery disease; furthermore, CAC predicts future events independently of concomitant conventional cardiovascular risk factors and to a greater extent than any other noninvasive biomarker of this disease. Nevertheless, the relationship between CAC and the susceptibility of a plaque to provoke a thrombotic event remains incompletely understood. This review summarizes the current understanding and literature on CAC. It outlines the pathophysiology of CAC and reviews laboratory, histopathological, and genetic studies, as well as imaging findings, to characterize different types of calcification and to elucidate their implications. Some patterns of calcification such as microcalcification portend increased risk of rupture and cardiovascular events and may improve prognosis assessment noninvasively. However, contemporary computed tomography cannot assess early microcalcification. Limited spatial resolution and blooming artifacts may hinder estimation of degree of coronary artery stenosis. Technical advances such as photon counting detectors and combination with nuclear approaches (eg, NaF imaging) promise to improve the performance of cardiac computed tomography. These innovations may speed achieving the ultimate goal of providing noninvasively specific and clinically actionable information.

Carotid artery stenosis is a major cause of morbidity and mortality. The journey to understanding carotid disease has developed over time and radiology has a pivotal role in diagnosis, risk stratification and therapeutic management. This paper reviews the history of diagnostic imaging in carotid disease, its evolution towards its current applications in the clinical and research fields, and the potential of new technologies to aid clinicians in identifying the disease and tailoring medical and surgical treatment.