Sex Differences in Carotid Plaque Composition in Patients With Embolic Stroke of Undetermined Source

Sex-Specific Risk Factors of Nonstenotic Carotid Plaque in Embolic Stroke of Unknown Source: A Case-Control Study

BACKGROUND

Many ischemic strokes are diagnosed as embolic strokes of undetermined source (ESUS). Recent evidence suggests that nonstenotic carotid plaque (nsCP) may be a substantial contributor to the risk for ESUS. We aimed to investigate the risk factor profile associated with nsCP in ESUS and defined stroke etiologies.

METHODS

In this retrospective case-control study, we investigated consecutive patients with acute ischemic stroke due to ESUS, small-vessel disease, or cardioembolism proven by magnetic resonance imaging. The association of vascular risk factors age, arterial hypertension, diabetes, dyslipoproteinemia, body mass index, alcohol consumption, tobacco use, kidney failure, and history of stroke with the presence of nsCP was investigated using binary logistic regression analysis and further stratified by stroke etiology and sex.

RESULTS

In total, 609 patients (median age, 76 years; 46% women) who were treated from 2018 to 2020 were considered. In patients with ESUS, sex played a more important role for the prevalence of nsCP than in defined etiologies. Female patients with ESUS had lower odds of exhibiting nsCP compared with male patients with ESUS (adjusted odds ratio, 0.36 [95% CI, 0.15-0.86]). In male patients with ESUS, we observed that age (adjusted odds ratio per 10-year increase, 2.55 [95% CI, 1.26-5.17]) and hypertension (adjusted odds ratio, 2.49 [95% CI, 0.56-11.1]) were the main risk factors for nsCP, whereas in female patients with ESUS also tobacco use was particularly relevant (adjusted odds ratio, 3.71 [95% CI, 0.61-22.5]). These results were in line with a sensitivity analysis in nsCP located ipsilateral to the infarct.

CONCLUSIONS

Sex differences play an important role in nsCP prevalence in patients with ESUS. These findings may have important implications for the management in targeted secondary prevention following ESUS.

Age-dependent sex differences in non-stenotic intracranial plaque of embolic stroke of undetermined source

Age and sex have effect on atherosclerosis. This study aimed to investigate their effect on non-stenotic intracranial atherosclerotic plaque (NIAP) in embolic stroke of undetermined source (ESUS) using high-resolution magnetic resonance imaging (HR-MRI). We retrospectively recruited consecutive ESUS patients who underwent intracranial HR-MRI to assess the plaque characteristics (remodeling index [RI], plaque burden [PB], fibrous cap [FC], discontinuity of plaque surface [DPS], intraplaque hemorrhage [IPH] and complicated plaque [CP]). We divided patients into three groups (< 60 years, 60-74 years, ≥ 75 years). 155 patients with ipsilateral NIAP were found from 243 ESUS patients, with 106 men (68.39%) and 49 women (31.61%). In total population or age group under 60 years, there were no significant differences in plaque characteristics between men and women (all p > 0.05). In age group of 60-74 years, men were associated with higher PB (66.27 ± 9.17% vs 60.91 ± 8.86%, p = 0.017) and RI (1.174 vs 1.156, p = 0.019), higher prevalence of DPS (82.50% vs 60.00%, p = 0.036) and complicated plaque (85.00% vs 63.33%, p = 0.036). For subjects ≥ 75 years old, PB were significantly higher in twomen vs men (68.85 ± 6.14% vs 62.62 ± 7.36%, p = 0.040). In addition, the probability for PBupper (≥ median PB), RIupper (≥ median RI) and vulnerable plaque increased as age increased, and its predictive power for index ESUS was higher in men than women. This study identified age-dependent sex differences in NIAP characteristics of ESUS patients, which will help us clarify their etiology.

Extracranial Carotid Plaque Calcification and Cerebrovascular Ischemia: A Systematic Review and Meta-Analysis

BACKGROUND

Although coronary calcification quantification is an established approach for cardiovascular risk assessment, the value of quantifying carotid calcification is less clear. As a result, we performed a systematic review and meta-analysis to evaluate the association between extracranial carotid artery plaque calcification burden and ipsilateral cerebrovascular ischemic events.

METHODS

A comprehensive literature search was performed in the following databases: Ovid MEDLINE(R) 1946 to July 6, 2022; OVID Embase 1974 to July 6, 2022; and The Cochrane Library (Wiley). We performed meta-analyses including studies in which investigators performed a computed tomography assessment of calcification volume, percentage, or other total calcium burden summarizable in a single continuous imaging biomarker and determined the association of these features with the occurrence of ipsilateral stroke or transient ischemic attack.

RESULTS

Our overall meta-analysis consisted of 2239 carotid arteries and 9 studies. The presence of calcification in carotid arteries ipsilateral to ischemic stroke or in stroke patients compared with asymptomatic patients did not demonstrate a significant association with ischemic cerebrovascular events (relative risk of 0.75 [95% CI, 0.44-1.28]; P=0.29). When restricted to studies of significant carotid artery stenosis (>50%), the presence of calcification was associated with a reduced risk of ischemic stroke (relative risk of 0.56 [95% CI, 0.38-0.85]; P=0.006). When the analysis was limited to studies of patients with mainly nonstenotic plaques, there was an increased relative risk of ipsilateral ischemic stroke of 1.72 ([95% CI, 1.01-2.91]; P=0.04). Subgroup meta-analyses of total calcium burden and morphological features of calcium showed wide variability in their strength of association with ischemic stroke and demonstrated significant heterogeneity.

CONCLUSIONS

The presence of calcification in carotid plaque confers a reduced association with ipsilateral ischemic events, although these results seem to be limited among carotid arteries with higher degrees of stenosis. Adoption of carotid calcification measures in clinical decision-making will require additional studies providing more reproducible and standardized methods of calcium characterization and testing these imaging strategies in prospective studies.

Sex differences in outcome after carotid revascularization in symptomatic and asymptomatic carotid artery stenosis

OBJECTIVE

Sex differences regarding the safety and efficacy of carotid revascularization in carotid artery stenosis have been addressed in several studies with conflicting results. Moreover, women are underrepresented in clinical trials, leading to limited conclusions regarding the safety and efficacy of acute stroke treatments.

METHODS

A systematic review and meta-analysis was performed by literature search including four databases from January 1985 to December 2021. Sex differences in the efficacy and safety of revascularization procedures, including carotid endarterectomy (CEA) and carotid artery stenting (CAS), for symptomatic and asymptomatic carotid artery stenoses were analyzed.

RESULTS

Regarding CEA in symptomatic carotid artery stenosis, the stroke risk in men (3.6%) and women (3.9%) based on 99,495 patients (30 studies) did not differ (P = .16). There was also no difference in the stroke risk by different time frames up to 10 years. Compared with men, women treated with CEA had a significantly higher stroke or death rate at 4 months (2 studies, 2565 patients; 7.2% vs 5.0%; odds ratio [OR], 1.49; 95% confidence interval [CI], 1.04-2.12; I2 = 0%; P = .03), and a significantly higher rate of restenosis (1 study, 615; 17.2% vs 6.7%; OR, 2.81; 95% CI, 1.66-4.75; P = .0001). For CAS in symptomatic artery stenosis, data showed a non-significant tendency toward higher peri-procedural stroke in women, whereas for asymptomatic carotid artery stenosis, data based on 332,344 patients showed that women (compared with men) after CEA had similar rates of stroke, stroke or death, and the composite outcome stroke/death/myocardial infarction. The rate of restenosis at 1 year was significantly higher in women compared with men (1 study, 372 patients; 10.8% vs 3.2%; OR, 3.71; 95% CI, 1.49-9.2; P = .005). Furthermore, CAS in asymptomatic patients was associated with low risk of a postprocedural stroke in both sexes, but a significantly higher risk of in-hospital myocardial infarction in women than men (8445 patients, 1.2% vs 0.6%; OR, 2.01; 95% CI, 1.23-3.28; I2 = 0%; P = .005).

CONCLUSIONS

A few sex-differences in short-term outcomes after carotid revascularization for symptomatic and asymptomatic carotid artery stenosis were found, although there were no significant differences in the overall stroke. This indicates a need for larger multicenter prospective studies to evaluate these sex-specific differences. More women, including those aged over 80 years, need to be enrolled in randomized controlled trials, to better understand if sex differences exist and to tailor carotid revascularization accordingly.

Association Between Spotty Calcification in Nonstenosing Extracranial Carotid Artery Plaque and Ipsilateral Ischemic Stroke

Background Small spotty calcifications in the coronary arteries are associated with an increased risk of myocardial infarction. We examined the association between spotty calcifications near the carotid bifurcations and ipsilateral ischemic stroke in patients with <50% luminal stenosis of the extracranial carotid arteries. Methods and Results We used data from the CAESAR (Cornell Acute Stroke Academic Registry), a prospective registry of all patients with acute ischemic stroke admitted to our institution. We included patients who met criteria for cryptogenic stroke and underwent computed tomography angiography and brain magnetic resonance imaging. Patients with extracranial carotid artery stenosis ≥50% and patients with posterior or bilateral anterior circulation infarcts were excluded. We examined the carotid bifurcations for spotty calcifications, defined as ≥1 contiguous regions of luminal calcification ≤3 mm along the long axis of the vessel. We also measured low-density plaque and maximum plaque thickness. The eligible cohort consisted of 117 patients with a mean age of 66.7±1.65 years with a median National Institute of Health Stroke Scale stroke at the time of arrival of 6 (range, 3-13). The number of spotty calcifications present within a low-density plaque was significantly associated with ipsilateral infarction (0.3±0.8 versus 0.1±0.4, P=0.02). Maximum plaque thickness was also significantly associated with ipsilateral infarction (1.4 mm ±1.5 versus 1.0 mm ±1.1, P=0.004). Conclusions Spotty calcifications associated with low-density plaque and maximum plaque thickness were associated with ipsilateral ischemic stroke in patients with nonstenotic carotid atherosclerosis, suggesting a role as imaging markers of high-risk plaque.

Sex Differences in Carotid Atherosclerosis: A Systematic Review and Meta-Analysis

BACKGROUND

Over the last decades, several individual studies on sex differences in carotid atherosclerosis have been performed covering a wide range of plaque characteristics and including different populations. This systematic review and meta-analysis aims to summarize previously reported results on sex differences in carotid atherosclerosis and present a roadmap explaining next steps needed for implementing this knowledge in clinical practice.

METHODS

We systematically searched PubMed, Embase, Web of Science, Cochrane Central, and Google Scholar for eligible studies including both male and female participants reporting prevalence of imaging characteristics of carotid atherosclerosis and meta-analyzed these studies. Studies had to report at least the following: (1) calcifications; (2) lipid-rich necrotic core; (3) intraplaque hemorrhage; (4) thin-or-ruptured fibrous cap; (5) plaque ulceration; (6) degree of stenosis; (7) plaque size; or (8) plaque inflammation. We prespecified which imaging modalities had to be used per plaque characteristic and excluded ultrasonography.

RESULTS

We included 42 articles in our meta-analyses (ranging from 2 through 23 articles per plaque characteristic). Men had more frequently a larger plaque compared to women and, moreover, had more often plaques with calcifications (odds ratio=1.57 [95% CI, 1.23-2.02]), lipid-rich necrotic core (odds ratio=1.87 [95% CI, 1.36-2.57]), and intraplaque hemorrhage (odds ratio=2.52 [95% CI, 1.74-3.66]), or an ulcerated plaque (1.81 [95% CI, 1.30-2.51]). Furthermore, we found more pronounced sex differences for lipid-rich necrotic core in symptomatic opposed to asymptomatic participants.

CONCLUSIONS

In this systematic review and meta-analysis, we demonstrate convincing evidence for sex differences in carotid atherosclerosis. All kinds of plaque features-plaque size, composition, and morphology-were more common or larger in men compared to women. Our results highlight that sex is an important variable to include in both study design and clinical-decision making. Further investigation of sex-specific stroke risks with regard to plaque composition is warranted.

Quantitative and qualitative features of carotid and coronary atherosclerotic plaque among men and women

Cardiovascular diseases (CVDs), particularly ischemic heart disease (IHD) and stroke, present epidemiologically in a different way among sexes. The reasons of these sex-based differences should be delved into sex-specific cardiovascular (CV) risk factors and different mechanisms of atherosclerotic progression. Imaging techniques of both carotid and coronary atherosclerotic plaques represent a tool to demonstrate sex-related features which might be used to further and better assess CV risk of male and female population. The aim of this review is to evaluate current knowledge on sex-specific qualitative and quantitative plaque features of coronary and carotid atherosclerosis. We also discuss the clinical implication of a sex-based plaque phenotype, evaluated with non-invasive imaging techniques, such as CT-angiography and MRI-angiography, to stratify CV risk.

Carotid Interventions for Women: The Hazards and Benefits

The goal of the current review is to examine the hazards and benefits of carotid interventions in women and to provide recommendations for the indications for carotid intervention in female patients. Stroke and cerebrovascular disease are prevalent in women. There are inherent biological and other differences in men and women, which affect the manifestations and outcome of stroke, with women experiencing worse disability and higher mortality following ischemic stroke than men. Due to the underrepresentation of female patients in most clinical trials, the ability to make firm but alternative recommendations for women specifically on the management of carotid stenosis is challenging. Although some data suggest that women might have worse periprocedural outcomes as compared to men following all carotid revascularization procedures, there is also an abundance of data to support a similar risk for carotid procedures in men and women, especially with carotid endarterectomy and transcarotid artery revascularization. Therefore, the indications for carotid revascularization are the same in women as they are in men. The choice of a carotid revascularization procedure in women is based upon the same factors as in men and requires careful evaluation of a particular patient's risk profile, anatomic criteria, plaque morphology, and medical comorbidities that might favor one technique over the other. When performing carotid revascularization procedures in women, tailored techniques and procedures to address the small diameter of the female artery are warranted.

Sex Differences in Carotid Plaque Composition in Patients With Embolic Stroke of Undetermined Source

Background

We examined sex differences in nonstenotic carotid plaque composition in patients with embolic stroke of undetermined source (ESUS).

Methods and Results

Patients with anterior circulation ischemic stroke imaged with neck computed tomographic angiography who met criteria for ESUS or had atrial fibrillation were identified. Patients with atrial fibrillation were included as a negative control. Semiautomated plaque quantification software analyzed carotid artery bifurcations. Plaque subcomponent (calcium, intraplaque hemorrhage [IPH], and lipid rich necrotic core) volumes were compared by sex and in paired analyses of plaque ipsilateral versus contralateral to stroke. Multivariate linear regressions tested for associations. Ninety‐four patients with ESUS (55% women) and 95 patients with atrial fibrillation (47% women) were identified. Men with ESUS showed significantly higher volumes of calcified plaque (63.9 versus 19.6 mm³, P<0.001), IPH (9.4 versus 3.3 mm³, P=0.008) and a IPH/lipid rich necrotic core ratio (0.17 versus 0.07, P=0.03) in carotid plaque ipsilateral to stroke side than women. The atrial fibrillation cohort showed no significant sex differences in plaque volumes ipsilateral to stroke. Multivariate analyses of the ESUS cohort showed male sex was associated with IPH_ipsi (β=0.49; 95% CI, 0.11–0.87) and calcium_ipsi (β=0.78; 95% CI, 0.33–1.23). Paired plaque analyses in men with ESUS showed significantly higher calcified plaque (63.9 versus 34.1 mm³, P=0.03) and a trend of higher IPH_ipsi (9.4 versus 7.5 mm³, P=0.73) and lipid rich necrotic core_ipsi (59.0 versus 48.4 mm³, P=0.94) volumes.

Conclusions

Sex differences in carotid plaque composition in ESUS suggest the possibility of a differential contribution of nonstenosing carotid plaque as a stroke mechanism in men versus women.