Aortic atheromas in stroke subgroups detected by multidetector computed tomographic angiography

Imaging Biomarkers and Prevalence of Complex Aortic Plaque in Cryptogenic Stroke: A Systematic Review

BACKGROUND

Complex aortic plaque (CAP) is a potential embolic source in patients with cryptogenic stroke (CS). We review CAP imaging criteria for transesophageal echocardiogram (TEE), computed tomography angiography (CTA), and magnetic resonance imaging and calculate CAP prevalence in patients with acute CS.

METHODS AND RESULTS

PubMed and EMBASE databases were searched up to December 2022 in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guideline. Two independent reviewers extracted data on study design, imaging techniques, CAP criteria, and prevalence. The Cochrane Collaboration tool and Guideline for Reporting Reliability and Agreement Studies were used to assess risk of bias and reporting completeness, respectively. From 2293 studies, 45 were reviewed for CAP imaging biomarker criteria in patients with acute CS (N=37 TEE; N=9 CTA; N=6 magnetic resonance imaging). Most studies (74%) used ≥4 mm plaque thickness as the imaging criterion for CAP although ≥1 mm (N=1, CTA), ≥5 mm (N=5, TEE), and ≥6 mm (N=2, CTA) were also reported. Additional features included mobility, ulceration, thrombus, protrusions, and assessment of plaque composition. From 23 prospective studies, CAP was detected in 960 of 2778 patients with CS (0.32 [95% CI, 0.24-0.41], I2=94%). By modality, prevalence estimates were 0.29 (95% CI, 0.20-0.40; I2=95%) for TEE; 0.23 (95% CI, 0.15-0.34; I2=87%) for CTA and 0.22 (95% CI, 0.06-0.54; I2=92%) for magnetic resonance imaging.

CONCLUSIONS

TEE was commonly used to assess CAP in patients with CS. The most common CAP imaging biomarker was ≥4 mm plaque thickness. CAP was observed in one-third of patients with acute CS. However, high study heterogeneity suggests a need for reproducible imaging methods.

Contributing Mechanisms of Aortic Atheroma in Ischemic Cerebrovascular Disease

In recent years, the correlation between aortic atheroma (AA) and the occurrence and recurrence of ischemic cerebrovascular disease (ICVD) has attracted much attention, but the contributory mechanisms remain controversial. This review analyzes related research on the roles of AA in ICVD, and demonstrates the correlation between the formation and development of AA and abnormal metabolism, inflammation, hemodynamic changes, and other contributory factors. The presence of complex aortic plaque (CAP) in the ascending aorta and aortic arch increases the risk of cerebral embolism and degree of injury, while the association between CAP in the descending aorta and cerebral embolism remains ambiguous. AA also functions as an indicator of atherosclerosis burden as well as hypercoagulability, which may further increase the risk of ICVD. Further study on the relationship of AA to ICVD will improve diagnosis and treatment in clinical practice.

Atherosclerosis in intracranial, extracranial, and coronary arteries with aortic plaques in patients with ischemic stroke of undetermined etiology

OBJECTIVE

We investigated the association of cerebral and coronary artery atherosclerosis with the presence, burden and type of atherosclerotic plaques of the aorta (AP) in patients with ischemic stroke of undetermined etiology.

METHODS

48 consecutive patients (32 males, mean age 68 ± 11 years) with acute ischemic stroke of unknown etiology after thorough stroke workup were investigated using ECG-gated CT-Angiography (CTA) for the detection of embolic AP. Intima media thickness (IMT), presence of carotid plaques and stenosis ≥ 50% and intracranial stenosis were assessed as parameters of cerebral atherosclerosis, the Agatston score (AS) and coronary artery stenosis ≥ 50% (CAS) in CTA as parameters of coronary atherosclerosis. Plaque burden was classified as mild or severe and plaque types were classified according to their morphology in calcified, non-calcified or mixed.

RESULTS

APs were found in 36 patients (75%). AP presence was associated with higher IMT values (p = 0.029), intracranial stenosis (p = 0.047), CAS (p = 0.033) and AS (p = 0.026). Twenty-three of 31 (74.2%) patients with both carotid atherosclerosis and AP revealed plaque calcification (p = 0.041). Ten of 14 (71.4%) patients with AP and intracranial stenosis had calcified plaques (p = 0.030). AP in more than one aortic segment was found in patients with bilateral carotid stenosis ≥ 50% (p = 0.038), intracranial stenosis (p = 0.042), high IMT (p = 0.040) and higher AS (p = 0.019).

CONCLUSIONS

Aortic atherosclerotic plaques are common in patients with ischemic stroke of undetermined etiology and in particular those with carotid, intracranial and coronary atherosclerosis or high IMT values. In these patients, CTA of aorta should be seriously considered.

Repeated brain infarction caused by atherosclerosis of the bovine aortic arch successfully treated with arch replacement: case report

A 62-year-old man presented with repeated embolic infarction over the last 3 years. Computed tomography angiography of the aortic arch revealed that the patient had a common trunk for the innominate and left carotid arteries, the so-called bovine aortic arch, with stenosis extending to both the left common carotid artery and innominate artery. Since antiplatelet therapy was not adequate for prevention of recurrent infarction, total replacement of the aortic arch was performed. Since then, no further ischemic events have manifested. Endovascular procedures are not safe enough for atherosclerotic lesions in the aortic arch, especially in a patient with bovine aortic arch, so surgical aortic arch replacement should be considered.

CT angiography of the aorta is superior to transesophageal echocardiography for determining stroke subtypes in patients with cryptogenic ischemic stroke

BACKGROUND

The etiology of ischemic strokes remains cryptogenic in about one third of patients, even after extensive workup in specialized centers. Atherosclerotic plaques in the aorta can cause thromboembolic events but are often overlooked. They can elude standard identification by transesophageal echocardiography (TEE), which is invasive or at best uncomfortable for many patients. CT angiography (CTA) can be used as an alternative or in addition to TEE if this technique fails to visualize every part of the aorta and in particular the aortic arch.

METHODS

We prospectively studied 64 patients (47 men, age 60 ± 13 years) classified as having cryptogenic stroke after standard and full workup [including brain MRI and 24-hour electrocardiogram (ECG)] with ECG-triggered CTA of the aorta in search of plaques and compared the results with those of TEE. Investigators were blinded to the results of both techniques. Plaques were graded on CTA according to their presence (0 = not present; 1 = mild; 2 = severe) and degree of calcification (1a or 2a = noncalcified; 1b or 2b = calcified). Associations with risk factors and infarct localization were also assessed.

RESULTS

Only 21 of 64 patients (32.8%) had aortic plaques identified by TEE, compared to 43 of 64 (67.2%) with CTA (p < 0.05). The plaque localization was as follows (TEE vs. CTA): ascending aorta, 10 vs. 20 (p < 0.05); aortic arch, 10 vs. 40 (p < 0.05), and descending aorta, 20 vs. 34 (p < 0.05). Grade 1 plaques were most commonly found in the aortic arch (25; 39%), while grade 2 plaques were most often detected in the aortic arch (15; 23.4%) and the descending aorta (14; 21.9%). There was no significant correlation between plaque location, infarct territory or vascular risk profile, except for hypertension (p = 0.003), which was significantly associated with the presence of plaques.

CONCLUSIONS

CTA identifies more plaques throughout the aortic arch and around the origins of the major cerebral arteries in particular compared to TEE. These may represent potential embolic sources of acute ischemic stroke. Better plaque detection may have an impact on the best available secondary prevention regimen in individual patients if proximal embolic sources are suspected.

Comprehensive evaluation of coronary artery disease and aortic atherosclerosis in acute ischemic stroke patients: usefulness based on Framingham risk score and stroke subtype

BACKGROUND

Evaluation of coronary artery disease (CAD) and aortic atherosclerosis has been performed in patients with acute ischemic stroke. We investigated the usefulness of a dual-source CT (DSCT) protocol enabling the comprehensive evaluation of CAD and aortic atherosclerosis. The clinical characteristics of those patients who would benefit more from this protocol were investigated based on vascular risk factors, Framingham Risk Score (FRS), and stroke subtype.

METHODS

Of 469 patients with acute ischemic stroke, the 274 who had no history of CAD and had undergone DSCT were analyzed. Predictors of CAD (≥50% stenosis) or complicated aortic plaque (CAP) were evaluated based on vascular risk factors, FRS and stroke subtype.

RESULTS

Of the 274 patients analyzed, asymptomatic CAD (≥50% stenosis) was found in 61 (22.3%) and CAP in 58 (21.2%). Furthermore, the severity of CAD or aortic atherosclerosis was correlated with FRS (CAD, r = 0.291, p < 0.001 and aortic atherosclerosis, r = 0.297, p < 0.001). Additionally, severe CAD and aortic atherosclerosis were independent predictors of each other: CAP for the presence of CAD (≥50% stenosis) [odds ratio (OR), 5.71; 95% confidence interval (CI), 1.94-16.87]; CAD (≥50% stenosis) for the presence of CAP (OR, 4.20; 95% CI, 1.82-9.72). Specific stroke subtypes as well as large-artery atherosclerosis (OR, 5.25; 95% CI, 2.24-12.31) and cardioembolism (OR, 5.22; 95% CI, 1.75-15.60) were associated with the presence of CAP.

CONCLUSIONS

A comprehensive evaluation protocol for CAD and aortic atherosclerosis may be useful in acute ischemic stroke patients, especially in those with higher FRS or specific stroke subtypes.