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

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.

Prevalence of high-risk aortic arch atherosclerosis features on computed tomography angiography in embolic stroke of undetermined source

INTRODUCTION

Embolic stroke of undetermined source (ESUS) comprises a heterogenous group. There is a need to further identify etiologies within this group to guide management strategies. We examined the prevalence of aortic arch atherosclerosis (AAA) on CT angiography (CTA) in patients with embolic stroke of undetermined source (ESUS) to characterize high-risk plaque features.

METHODS

All patients from two prospective multicenter acute ischemic stroke studies (INTERRSeCT and PRove-IT) were included if the CTA adequately imaged the proximal aortic arch and the stroke etiology was recorded. Three readers blinded to stroke etiology analyzed the following AAA plaque features on baseline CTA at the time of stroke: 1) thickness in millimetres (mm); 2) morphology (none, smooth, ulcerated, or protruding); 3) location within the aortic arch (proximal, transverse, or distal); and 4) calcification (none, single small, multiple small, single large, or diffuse extensive).

RESULTS

We included 1063 patients, of which 293 (27.6%) had ESUS (mean age 67.5 years; 46.4% men; median NIHSS 12; 80.6% large vessel occlusion). Mean AAA thickness was significantly larger in ESUS patients (3.8 mm) compared to non-ESUS patients (3.0 mm; p<0.0001) and to a subgroup of patients with large artery atherosclerosis (2.9 mm; p=0.003). ESUS patients had a significantly higher proportion of ulcerated or protruding plaques (17.4% vs 10.3%; risk ratio 1.7, 95% C.I. 1.2-2.4, p=0.002). The location of AAA in the ESUS group was the ascending aorta in 37.9%, transverse arch in 42.3%, and descending aorta in 84.6%. Although AAA was mostly located in the distal aortic arch, ulcerated or protruding plaques were least common in the distal arch (p=0.002). There was no difference between ESUS and non-ESUS patients in plaque location (p=0.23) or calcification grade (p=0.092).

CONCLUSION

ESUS patients in our study had thicker AAA and a higher prevalence of ulcerated or protruding plaques located more proximally within the aortic arch. High-risk plaque features may suggest a causal role of AAA in the ESUS population with visible intracranial occlusions.

Characterization of aortic aging using 3D multi-parametric MRI-long-term follow-up in a population study

We comprehensively studied morphological and functional aortic aging in a population study using modern three-dimensional MR imaging to allow future comparison in patients with diseases of the aortic valve or aorta. We followed 80 of 126 subjects of a population study (20 to 80 years of age at baseline) using the identical methodology 6.0 ± 0.5 years later. All underwent 3 T MRI of the thoracic aorta including 3D T1 weighted MRI (spatial resolution 1 mm³) for measuring aortic diameter and plaque thickness and 4D flow MRI (spatial/temporal resolution = 2 mm³/20 ms) for calculating global and regional aortic pulse wave velocity (PWV) and helicity of aortic blood flow. Mean diameter of the ascending aorta (AAo) decreased and plaque thickness increased significantly in the aortic arch (AA) and descending aorta (DAo) in females. PWV of the thoracic aorta increased (6.4 ± 1.5 to 7.0 ± 1.7 m/s and 6.8 ± 1.5 to 7.3 ± 1.8 m/s in females and males, respectively) over time. Local normalized helicity volumes (LNHV) decreased significantly in the AAo and AA (0.33 to 0.31 and 0.34 to 0.32 in females and 0.34 to 0.32 and 0.32 to 0.28 in males). By contrast, helicity increased significantly in the DAo in both genders (0.28 to 0.29 and 0.29 to 0.30, respectively). 3D MRI was able to characterize changes in aortic diameter, plaque thickness, PWV and helicity during six years in our population. Aortic aging determined by 3D multi-parametric MRI is now available for future comparisons in patients with diseases of the aortic valve or aorta.

CALA: Cumulative Volume of Calcified Lesions of the Aorta in Cardiac Surgery

One of the major key questions raised in this retrospective study was to identify any correlation of atherosclerotic plaque volume of the ascending aorta and aortic arch with adverse events such as postoperative stroke, critical illness polyneuropathy and myopathy, as well as delirium and all-cause in-hospital mortality. In a second phase of this study, we investigated the relationship between atherosclerotic plaque volume and adverse events regarding the construction of proximal anastomosis on coronary artery bypass grafting procedures using different clamping techniques such as construction of anastomosis on cross-clamping or cross-clamping plus consecutive partial clamping of the aorta. The key findings of our research were that the size of calcium lesions of the ascending aorta and aortic arch correlates with early mortality, critical illness polyneuropathy/myopathy, and delirium but not with stroke. On the other hand, there were no significant differences between isolated cross-clamping versus cross-clamping plus consecutive partial clamping of the aorta regarding the primary adverse events by means of mean plaque volume.

Surgical strategies for severely atherosclerotic (porcelain) aorta during coronary artery bypass grafting

Porcelain aorta (PA) is an asymptomatic atherosclerotic disease, characterized by circumferential calcification throughout the whole perimeter of the aorta. It is seen in 2% to 9.3% of patients undergoing elective coronary artery bypass grafting (CABG) and makes manipulation of the ascending aorta impossible. It has been clearly shown that most emboli seen and detected during the CABG procedure occur during aortic cross-clamping and aortic side-clamping. Manipulation of porcelain or a severely atherosclerotic aorta increases the risk of perioperative stroke. The incidence of stroke after CABG is between 0.48% and 2.9%, and the risk is correlated with the extent and severity of the atherosclerotic disease. A conventional CABG procedure involves successive steps that include cannulation of the ascending aorta, application of a cross-clamp to the aorta, and partial clamping of the aorta to create the proximal anastomosis. Therefore in procedures that involve cannulation, clamping, or proximal anastomosis, and where aortic manipulation is inevitable, preassessment of the atherosclerotic aortic plaques is crucial. Although many surgeons still rely on intraoperative manual aortic palpation, this approach has very low sensitivity and underestimates the severity of the atherosclerotic illness. Imaging methods including preoperative computed tomography or intraoperative epiaortic ultrasonography enable modification of the surgical technique according to the severity of atherosclerosis. Various surgical techniques have been described to reduce the risk of atheroembolism that may lead to cerebrovascular events in patients with severely atherosclerotic ascending aorta. Anaortic or “no-touch” techniques that do not utilize aortic manipulation may significantly decrease the development of neurological complications by avoiding aortic maneuvers known to cause emboli. In cases where severe atherosclerotic disease or other factors preclude safe use of the ascending aorta, modifications in the surgical techniques, such as switching to different cannulation sites including the axillary/subclavian, femoral and innominate arteries, or using hypothermic ventricular fibrillation and in-situ pedicled arterial grafts, or performing proximal anastomoses at alternative anatomical locations will enable CABG operations to be performed safely with low morbidity and mortality rates in patients with porcelain aortas.

Expert opinion paper on cardiac imaging after ischemic stroke

This expert opinion paper on cardiac imaging after acute ischemic stroke or transient ischemic attack (TIA) includes a statement of the "Heart and Brain" consortium of the German Cardiac Society and the German Stroke Society. The Stroke Unit-Commission of the German Stroke Society and the German Atrial Fibrillation NETwork (AFNET) endorsed this paper. Cardiac imaging is a key component of etiological work-up after stroke. Enhanced echocardiographic tools, constantly improving cardiac computer tomography (CT) as well as cardiac magnetic resonance imaging (MRI) offer comprehensive non- or less-invasive cardiac evaluation at the expense of increased costs and/or radiation exposure. Certain imaging findings usually lead to a change in medical secondary stroke prevention or may influence medical treatment. However, there is no proof from a randomized controlled trial (RCT) that the choice of the imaging method influences the prognosis of stroke patients. Summarizing present knowledge, the German Heart and Brain consortium proposes an interdisciplinary, staged standard diagnostic scheme for the detection of risk factors of cardio-embolic stroke. This expert opinion paper aims to give practical advice to physicians who are involved in stroke care. In line with the nature of an expert opinion paper, labeling of classes of recommendations is not provided, since many statements are based on expert opinion, reported case series, and clinical experience.

Predictive Value of Cardiac CTA, Cardiac MRI, and Transthoracic Echocardiography for Cardioembolic Stroke Recurrence

BACKGROUND. Transthoracic echocardiography (TTE) is the standard of care for initial evaluation of patients with suspected cardioembolic stroke. Although TTE is useful for assessing certain sources of cardiac emboli, its diagnostic capability is limited in the detection of other sources, including left atrial thrombus and aortic plaques. OBJECTIVE. The purpose of this article was to investigate sensitivity, specificity, and predictive value of cardiac CTA (CCTA), cardiac MRI (CMRI), and TTE for recurrence in patients with suspected cardioembolic stroke. METHODS. We retrospectively included 151 patients with suspected cardioembolic stroke who underwent TTE and either CMRI (n = 75) or CCTA (n = 76) between January 2013 and May 2017. We evaluated for the presence of left atrial thrombus, left ventricular thrombus, vulnerable aortic plaque, cardiac tumors, and valvular vegetation as causes of cardioembolic stroke. The end point was stroke recurrence. Sensitivity, specificity, PPV, and NPV for recurrent stroke were calculated; the diagnostic accuracy of CMRI, CCTA, and TTE was compared between and within groups using AUC. RESULTS. Twelve and 14 recurrent strokes occurred in the CCTA and CMRI groups, respectively. Sensitivity, specificity, PPV, and NPV were 33.3%, 93.7%, 50.0%, and 88.2% for CCTA; 14.3%, 80.3%, 14.3%, and 80.3% for CMRI; 14.3%, 83.6%, 16.7%, and 80.9% for TTE in the CMRI group; and 8.3%, 93.7%, 20.0%, and 84.5% for TTE in the CCTA group. Accuracy was not different (p > .05) between CCTA (AUC = 0.63; 95% CI, 0.49-0.77), CMRI (0.53; 95% CI, 0.42-0.63), TTE in the CMRI group (0.51; 95% CI, 0.40-0.61), and TTE in the CCTA group (0.51; 95% CI, 0.42-0.59). In the CCTA group, atrial and ventricular thrombus were detected by CCTA in three patients and TTE in one patient; in the CMRI group, thrombus was detected by CMRI in one patient and TTE in two patients. CONCLUSION. CCTA, CMRI, and TTE showed comparably high specificity and NPV for cardioembolic stroke recurrence. CCTA and CMRI may be valid alternatives to TTE. CCTA may be preferred given potentially better detection of atrial and ventricular thrombus. CLINICAL IMPACT. CCTA and CMRI have similar clinical performance as TTE for predicting cardioembolic stroke recurrence. This observation may be especially important when TTE provides equivocal findings.

Aortic Sources of Embolism

Aortic arch atheroma is a frequent finding in ischemic stroke patients. Its role as a source of cerebral emboli or a marker of atherosclerosis is unclear. Transesophageal echography is considered the gold standard for its detection, whereas computed tomography angiography is a good alternative; magnetic resonance and positron emission tomography could be proposed to better analyze plaque vulnerability. Despite the interest in this condition, the optimal antithrombotic treatment remains uncertain, while intensive lipid-lowering therapy should be recommended. This review aims to offer guidance on patients with aortic arch atheroma, about its causal role in stroke, diagnosis, and treatment based on current available evidence.

CT Angiography of the Heart and Aorta in TIA and Ischaemic Stroke: Cardioembolic Risk Sources and Clinical Implications

BACKGROUND

Cardiac emboli are important causes of (recurrent) ischaemic stroke. Aorta atherosclerosis might also be associated with an increased risk of stroke recurrence. This study aimed to evaluate the yield and clinical implications of CT-angiography (CTA) of the heart and aorta in the diagnostic workup of transient ischaemic attack (TIA) or ischaemic stroke.

METHODS

CTA of the heart and aortic arch was performed in TIA/ischaemic stroke patients, in addition to routine diagnostic workup. Occurrence of cardioembolic (CE) risk sources and complex aortic plaques were assessed. Implications of cardiac CTA for therapeutic management were evaluated RESULTS: Sixty-seven patients were included (TIA n = 33, ischaemic stroke n = 34) with a mean age of 68 years (range 51-89) and median NIHSS of 0 (interquartile range 0-2). CE risk sources were detected in 29 (43%) patients. An intracardiac thrombus was present in 2 patients (3%; TIA 0%; ischaemic stroke 6%). Medium/low-risk CE sources included mitral annular calcification (9%), aortic valve calcification (18%) and patent foramen ovale (18%). Complex aortic plaque was identified in 16 patients (24%). In two patients with an intracardiac thrombus, therapeutic management changed from antiplatelet to oral anticoagulation.

CONCLUSIONS

CTA of the heart and aorta has a high yield for detection of embolic risk sources in TIA/ischaemic stroke, with clinical consequences for 6% of ischaemic stroke patients. Implementation of CTA of the heart and aorta in the acute stroke setting seems valuable, but cost-effectiveness of this approach remains to be determined.

Coronary artery bypass grafting and perioperative stroke: imaging of atherosclerotic plaques in the ascending aorta with ungated high-pitch CT-angiography

Perioperative stroke is a devastating complication after coronary artery bypass graft (CABG) surgery, with atherosclerosis of the ascending aorta as important risk factor. During surgical manipulation, detachment of plaques can lead to consecutive embolization into brain-supplying arteries. High-pitch computed tomography angiography (HP-CTA) represents a non-invasive imaging modality, which provides the opportunity for comprehensive imaging of the ascending aorta, including plaque detection and advanced characterization. In our present retrospective study on 719 individuals, who had undergone HP-CTA within 6 months prior to CABG, atherosclerotic disease of the ascending aorta was evaluated with respect to perioperative stroke rates. For image analysis, the ascending aorta was divided into a proximal and distal part, consisting of four segments, and evaluated for presence and distribution of calcified and mixed plaques. All patients with perioperative stroke presented with atherosclerotic disease of the ascending aorta. The stroke rate was significantly associated with the presence and extent of atherosclerotic disease. Patients burdened with mixed plaques presented with significantly higher perioperative stroke rates. This study demonstrates that HP-CTA allows accurate evaluation of plaque extent and composition in the ascending aorta, and therefore may improve risk stratification of stroke prior to CABG.

Cardiovascular computed tomography versus transoesophageal echocardiography after cryptogenic ischaemic stroke – a pilot study of 12 patients

Objective

Transoesophageal echocardiography (TEE) is the gold standard for the detection of cardiac emboli sources in ischaemic stroke patients, but new computed tomography (CT) scanners are able to visualize the heart. This pilot study aimed to compare findings on TEE with combined cardiovascular scan and cerebral CT angiography in cryptogenic ischaemic stroke patients.

Methods

This pilot study enrolled patients with cryptogenic ischaemic stroke who underwent a combined cardiovascular and cerebral CT angiography scan and a TEE examination, which were interpreted in a blinded manner.

Results

Twelve patients with cryptogenic ischaemic stroke were included (mean age 56 years). Of these, 10 patients underwent both a combined cardiovascular and cerebral CT angiography and a TEE examination. All cardiovascular CT scans were readable at sinus rhythm. None of the simultaneous cerebral angiograms were compromised. Thrombi were not detected in any patients. Patent foramen ovale was visualized in five patients by TEE, while cardiovascular CT only identified three. Cardiovascular CT revealed in addition an X-ray negative pulmonary metastasis in one patient, aortic coarctation in another and significant coronary stenosis in four patients.

Conclusion

The sensitivity for detecting patent foramen ovale was considerably lower for cardiovascular CT than for TEE, however the cardiovascular CT revealed several other very important clinical findings.

Predicting asymptomatic coronary artery stenosis by aortic arch plaque in acute ischemic cerebrovascular disease: beyond the cervicocephalic atherosclerosis?

Background:

Asymptomatic coronary artery stenosis (ACAS) ≥50% is common in patients with acute ischemic cerebrovascular disease (AICVD), which portends a poor cardiovascular and cerebrovascular prognosis. Identifying ACAS ≥50% early may optimize the clinical management and improve the outcomes of these high-risk AICVD patients. This study aimed to investigate whether aortic arch plaque (AAP), an early atherosclerotic manifestation of brain blood-supplying arteries, could be a predictor for ACAS ≥50% in AICVD.

Methods:

In this cross-sectional study, atherosclerosis of the coronary and brain blood-supplying arteries was simultaneously evaluated using one-step computed tomography angiography (CTA) in AICVD patients without coronary artery disease history. The patients were divided into ACAS ≥50% and non-ACAS ≥50% groups according to whether CTA showed stenosis ≥50% in at least one coronary arterial segment. The AAP characteristics of CTA were depicted from aspects of thickness, extent, and complexity.

Results:

Among 118 analyzed patients with AICVD, 29/118 (24.6%) patients had ACAS ≥50%, while AAPs were observed in 86/118 (72.9%) patients. Increased AAP thickness per millimeter (adjusted odds ratio [OR]: 1.56, 95% confidence interval [CI]: 1.18–2.05), severe-extent AAP (adjusted OR: 13.66, 95% CI: 2.33–80.15), and presence of complex AAP (adjusted OR: 7.27, 95% CI: 2.30–23.03) were associated with ACAS ≥50% among patients with AICVD, independently of clinical demographics and cervicocephalic atherosclerotic stenosis. The combination of AAP thickness, extent, and complexity predicted ACAS ≥50% with an area under the receiver-operating characteristic curve of 0.78 (95% CI: 0.70–0.85, P < 0.001). All three AAP characteristics provided additional predictive power beyond cervical and intracranial atherosclerotic stenosis for ACAS ≥50% in AICVD (all P < 0.05).

Conclusions:

Thicker, severe-extent, and complex AAP were significant markers of the concomitant ACAS ≥50% in AICVD, possibly superior to the indicative value of cervical and intracranial atherosclerotic stenosis. As an integral part of atherosclerosis of brain blood-supplying arteries, AAP should not be overlooked in predicting ACAS ≥50% for patients with AICVD.

Aortic and Internal Carotid Atherosclerosis in Patients with Carotid Stenosis: Semiautomatic Volumetric Analysis of Low-Attenuation Plaque on Curved Planar Reformations Using MDCT Angiographic Data

This retrospective study included 65 patients who underwent multidetector computed tomography (MDCT) carotid angiography; 28 patients were <70 years old (group 1), and 37 were ≥70 years old (group 2). Each low-attenuation (<30 Hounsfield units [HU]) plaque volume (LPV) and total uncalcified plaque volume ([TUPV] ≤150 HU) were semiautomatically measured on each aortic arch and internal carotid artery (ICA) curved planar reformations (CPR), using MDCT angiographic data. Correlation coefficients were employed to assess the impact of each plaque volume on various factors including ICA stenosis. The correlations (r > 0.5) were observed between aortic LPV and each ICA stenosis ratio and >30% stenosis in group 1, between aortic TUPV and male gender in group 1, and between ICA-TUPV and each aortic TUPV or the largest plaque thickness in group 2. Marginal correlations were observed between hyperlipidemia and aortic LPV and ICA-TUPV in group 1. There was no association between cerebral infarction and the aortic and ICA plaques. Both the aortic arch and ICA plaque volumes can be measured clinically. The increasing aortic LPV may be a significant factor associated with the development of ICA stenosis in patients younger than 70 years old.

Influence of Age Ranges on Relationship of Complex Aortic Plaque With Cervicocephalic Atherosclerosis in Ischemic Stroke

BACKGROUND

Complex aortic plaque is a potential cause of acute ischemic cerebrovascular disease, which needs timely identification. Also as a marker for systemic atherosclerosis, complex aortic plaque may be indicated by significant (≥50%) cervicocephalic atherosclerotic stenosis. We aimed at examining whether age ranges would influence their association to more accurately estimate the risk of having complex aortic plaque in acute ischemic cerebrovascular disease.

METHODS

Aortic arch and cervicocephalic arteries were simultaneously evaluated using computed tomography angiography. Middle-aged (45-64 years) and old-aged (65-85 years) acute ischemic cerebrovascular disease patients were divided into 2 groups according to whether there was an aortic arch plaque with thickness of greater than or equal to 4 mm or associated ulcerations or mural thrombus.

RESULTS

Old-aged patients (n = 107) had a higher prevalence of complex aortic plaque (67.3% versus 30.9%, P < .001) than those middle aged (n = 178). Among middle-aged patients, the presence of extracranial significant atherosclerotic stenosis (adjusted odd ratio = 2.89, 95% confidence interval: 1.42-5.86) rather than intracranial ones independently predicted complex aortic plaque. Regarding the extent of significant cervicocephalic atherosclerotic stenosis, the presence of multi-segment, bilateral, simultaneous extracranial and intracranial, and simultaneous anterior and posterior circulation ones were independent indicators for complex aortic plaque in the middle-aged subgroup (adjusted odd ratio = 2.42, 2.05, 2.26, 2.14, respectively). By contrast, no statistical correlation of complex aortic plaque and significant cervicocephalic atherosclerotic stenosis was found among old-aged patients.

CONCLUSION

Considering the ranges of age was important to more precisely predict complex aortic plaque with significant cervicocephalic atherosclerotic stenosis in acute ischemic cerebrovascular disease.

Semiautomatic Volumetry of Low Attenuation of Thoracic Aortic Plaques on Curved Planar Reformations Using MDCT Angiographic Data with 0.5 mm Collimation

To evaluate the relationship of aortic low attenuation plaque volume (LAPV) on multidetector computed tomography (MDCT) with the abdominal aortic aneurysm (AAA), the coronary arterial disease (CAD, ≥50% stenosis), severe (≥90% stenosis) CAD, hypertension, and long-term (≥10 years) hypertension. Curved planar reformations (CPR) of three segments (the ascending, the arch, and the upper descending aorta) of the thoracic aorta were generated with attenuation-dependent color codes to measure LAPV with 0~29 HU and total noncalcified plaque volume (TNPV) with 0~150 HU in 95 patients. Correlation coefficients were employed to assess the impact of each LAPV and TNPV on AAA, CAD, severe CAD, hypertension, and long-term hypertension. Each Mean LAPV/cm and TNPV/cm was statistically greater in the aortic arch than the ascending (p < 0.001 on each) or the proximal descending segment (p < 0.001 on each). LAPV in the aortic arch has moderate correlations with AAA, severe CAD, and long-term hypertension (r = 0.643, 0.639, 0.662, resp.). Plaque volumes in each aortic segment can be measured clinically and the increasing LAPV in the arch may be a significant factor associated with the development of severe atherosclerosis underlying AAA, severe CAD, and long-term hypertension.

Recent Advances in Primary and Secondary Prevention of Atherosclerotic Stroke

Atherosclerosis is a major cause of ischemic stroke that can be effectively prevented with appropriate lifestyle modifications and control of cardiovascular risk factors. Medical advances in recent years along with aggressive cardiovascular risk factor modifications have resulted in decreased recurrence rates of atherosclerotic stroke. Non-statin lipid-lowering molecules have recently shown clinical benefit and are recommended for very high-risk patients to reduce their risk of stroke. Aggressive hypertension treatment is crucial to reduce atherosclerotic stroke risk. Advances in antithrombotic treatments include combinations of antiplatelets and new antiplatelet agents in the acute phase post-stroke, which carries a high risk of recurrence. Intensive medical treatment has also limited the indications for carotid interventions, especially for asymptomatic disease. Intracranial atherosclerotic disease may provoke stroke through various mechanisms; it is increasingly recognized as a cause of ischemic stroke with advanced imaging and is best managed with lifestyle modifications and medical therapy. The diagnostic search for the vulnerable culprit atherosclerotic plaque is an area of intense research, from the level of the intracranial arteries to that of the aortic arch. Ultrasonography and novel magnetic resonance imaging techniques (high-resolution vessel-wall imaging) may assist in the identification of vulnerable atherosclerotic plaques as the underlying cause in cryptogenic or misdiagnosed non-atherosclerotic ischemic stroke. Vertebrobasilar atherosclerotic disease is less common than carotid artery disease; thus, high-quality data on effective prevention strategies are scarcer. However, aggressive medical treatment is also the gold standard to reduce cerebrovascular disease located in posterior circulation.

A Novel Evaluation for Predicting Aortic Complicated Lesions Using Calcification on Chest X-ray

BACKGROUND

The aorta is a significant source of cerebral thromboembolisms. Aortic complicated lesions (ACLs) are key findings on transesophageal echocardiography (TEE) for assessing aortic sources of emboli to the brain. TEE is sometimes avoided due to its invasiveness. However, few reports have examined alternative methods for predicting ACLs. We investigated relationships between aortic arch calcification (AAC) on chest X-ray and ACLs.

METHODS

Participants comprised 300 patients with acute ischemic stroke or transient ischemic attack who underwent TEE for the evaluation of the aortic arch and heart. A postero-anterior plain chest X-ray in the recumbent position was evaluated on admission for each patient. AAC was evaluated using 4 grades (0-3) and "AAC thickness" defined as the distance from the inner margin of the most distant AAC to the outer margin of the aortic vessel wall. ACLs were defined by intima-media thickness (IMT) ≥4.0 mm or presence of ulcerated or mobile plaques. Carotid maximum IMT on ultrasonography was also evaluated. Comparison of the diagnostic ability to predict ACL was performed between AAC grades and AAC thickness or AAC thickness and carotid maximum IMT using the Delong method.

RESULTS

ACLs were identified in 71 patients (23.7%), including ACLs with ulcerated plaques in 24 (8.0%) and ACLs with mobile plaques in 9 (3.0%). Plaque thickness was greater in higher AAC grades or higher quartiles of AAC thickness (p for trend <0.001 each). The Cochran-Armitage test showed that both higher AAC grade and higher quartile of AAC thickness were significantly associated with the presence of ACLs, as well as the presence of ulcerated or mobile plaques (p for trend < 0.001 each). Receiver-operating characteristic (ROC) analysis showed optimal cut-off values for AAC thickness of 5.6 mm for ACLs and 6.0 mm for ulcerated or mobile plaques. Multivariate logistic regression revealed a higher grade of AAC (grades 2-3) and AAC thickness (≥6 mm) as significantly associated with ACLs and ulcerated or mobile plaques (p < 0.001 each). ROC curve comparisons showed that AAC thickness offered a better marker of ACLs than AAC grade (p = 0.019), although no significant difference was evident between AAC thickness and carotid maximum IMT (p = 0.567).

CONCLUSIONS

AAC on chest X-ray, evaluated by both AAC grade and AAC thickness to the outer aortic vessel wall, was significantly associated with ACLs on TEE. AAC thickness was suggested as more useful than AAC grade and equivalent to carotid IMT in predicting ACLs.

Aortic Atherosclerosis Determines Increased Retrograde Blood Flow as a Potential Mechanism of Retrograde Embolic Stroke

BACKGROUND

Retrograde brain embolization from complex plaques of the proximal descending aorta (DAo) has been identified as a new potential mechanism of stroke. Our purpose was to identify predictors of increased retrograde aortic blood flow indicating an elevated risk of brain embolization from the DAo.

METHODS

A total of 485 patients with acute ischemic stroke were prospectively included and underwent transesophageal echocardiography. Blood flow velocities in the proximal DAo were studied using 2D pulse-wave Doppler ultrasound. Velocity-time integrals (VTI) were calculated for antegrade and retrograde velocity directions. The ratio (VTIretrograde/VTIantegrade) was used to estimate retrograde flow extent. Associations between patient demographics, cardiovascular risk factors, echocardiographic parameters, and VTIratio were analyzed using multivariate linear regression.

RESULTS

Retrograde blood flow in the DAo occurred in all patients. Velocity profiles in the proximal DAo were as follows (mean ± SD): VTIantegrade = 21.1 ± 6.5, VTIretrograde = 11.0 ± 3.6, and VTIratio = 0.54 ± 0.16. Diameter (r = 0.25, p < 0.001), presence of complex plaques (r = 0.12, p = 0.007), and reduced strain of the DAo (r = -0.23, p < 0.001) had significant partial effects in a predictor model based on predefined variables, which predicted 26% (adjusted R2 = 0.26) of the variance in VTIratio. A unit increase in the DAo diameter was associated with a 2% increase in VTIratio (95% CI 1-2.8%, p < 0.001). Presence of complex plaques increased VTIratio by 7% (95% CI 2-13%, p = 0.007) and an increase in strain by 0.1 indicated a decrease in VTIratio by about 11% (95% CI 6.2-15.5%, p < 0.001). Complex atheroma was found in the proximal DAo of 79 subjects, of which 40 (50.6%) had a VTIratio above average (VTIratio ≥0.54) compared to 87 of 261 (33.3%) patients without any complex plaques (p < 0.001). Twenty-five of 79 (31.7%) patients with complex DAo plaques had a VTIratio ≥0.60, which indicates a high likelihood of retrograde pathline length of ≥3 cm and thus increased risk of retrograde cerebral embolization. Stroke etiology of those 25 patients was determined in 13 and cryptogenic in 12 cases.

CONCLUSIONS

Retrograde blood flow in the DAo was found in all stroke patients. However, it increased further in patients with concomitant complex plaques, low strain, and/or large aortic diameter, that is, in those with atherosclerosis of the DAo. Accordingly, such patients may be predisposed to retrograde embolization in case of occurrence of a complex plaque in proximity to a brain-supplying artery.

Aortic Complex Plaque Predicts the Risk of Cryptogenic Ischemic Cerebrovascular Disease Recurrence

To evaluate the correlations between aortic complex plaque (ACP) and the recurrence of cryptogenic ischemic cerebrovascular disease (CICVD), and to investigate the clinical significance of ACP in CICVD. Methods CICVD patients (aged 17 to 84 years) admitted into the Department of Neurology, Xuanwu Hospital, from July 2011 to December 2013, were consecutively recruited, and divided into ACP and non-ACP groups according to head and neck computerized tomographic (CT) angiography. Recurrences of cerebral ischemic events (CIEs) were compared between these groups after follow-up. Results A total of 117 patients were enrolled (ACP group: 69, non-ACP group: 48) and followed up for a mean of 9.86 months (range: 3-33). The average age of the ACP group was 62.88 years, with 59.4% older than 60 years; the average age of the non-ACP group was 50.29 years, with 37.5% older than 60 years. At the 6-month follow-up, the recurrence rate of CIEs in the ACP group was significantly higher than that of the non-ACP group (17.0% [7/47] and 0% [0/36], respectively; χ2 = 4.283, P = 0.046). The cumulative recurrence risk for CIEs of the ACP group was significantly higher than for the non-ACP group (P = 0.004). Multivariate Cox survival analysis showed that ACP presence was an independent risk factor for CIE recurrence for CICVD patients (relative risk [RR] = 7.803, 95% confidence interval [CI], 1.827~33.319, P = 0.006). Conclusions ACP increased the recurrence risk of CIE in CICVD, and elderly CICVD patients should receive greater attention regarding the significance of ACP in recurrent CICVD.

Aortic arch and common carotid artery plaques with soft components pose a substantial risk of cerebral embolization during carotid stenting

OBJECTIVES

A higher rate of embolization is considered a disadvantage of carotid stenting (CAS), when compared with carotid endarterectomy. Plaques in the aortic arch (AA) and the common carotid artery (CCA) may be additional sources of embolization to stented internal carotid plaques during CAS. In this study, we aimed to investigate the relationship between these plaques and intracerebral embolization.

METHODS

We analyzed the occurrence and composition of plaques in the AA and CCA by computed tomography angiography (CTA) in 101 consecutive cases of CAS. Cases of peri-procedural embolization were detected on diffusion-weighted imaging as lesions demonstrating diffusion restriction. We applied the χ(2) and Fisher's exact tests, as well as logistic regression models.

RESULTS

The occurrence of plaques in the AA and CCA was significantly related to the appearance of new diffusion-weighted imaging lesions (p = 0.013 and p = 0.004, respectively). Patients with soft plaques in the AA or CCA had a significantly higher risk of embolization than those without plaques (p = 0.012 and p = 0.006, respectively). In contrast, homogeneously calcified plaques did not pose significantly higher risks.

CONCLUSIONS

Soft plaques in the AA and CCA result in a substantial risk of embolization during CAS. Use of a CTA examination of the AA and the CCA in patients with carotid stenosis may help to select lower-risk patients for CAS.

Non-invasive volumetric assessment of aortic atheroma: a core laboratory validation using computed tomography angiography

Aortic atherosclerosis has been linked with worse peri- and post-procedural outcomes following a range of aortic procedures. Yet, there are currently no standardized methods for non-invasive volumetric pan-aortic plaque assessment. We propose a novel means of more accurately assessing plaque volume across whole aortic segments using computed tomography angiography (CTA) imaging. Sixty patients who underwent CTA prior to trans-catheter aortic valve implantation were included in this analysis. Specialized software analysis (3mensio Vascular™, Pie Medical, Maastricht, Netherlands) was used to reconstruct images using a centerline approach, thus creating true cross-sectional aortic images, akin to those images produced with intravascular ultrasonography. Following aortic segmentation (from the aortic valve to the renal artery origin), atheroma areas were measured across multiple contiguous evenly spaced (10 mm) cross-sections. Percent atheroma volume (PAV), total atheroma volume (TAV) and calcium score were calculated. In our populations (age 79.9 ± 8.5 years, male 52 %, diabetes 27 %, CAD 84 %, PVD 20 %), mean ± SD number of cross sections measured for each patient was 35.1 ± 3.5 sections. Mean aortic PAV and TAV were 33.2 ± 2.51 % and 83,509 ± 17,078 mm(3), respectively. Median (IQR) calcium score was 1.5 (0.7-2.5). Mean (SD) inter-observer coefficient of variation and agreement for plaque area among 4 different analysts was 14.1 (5.4), and the mean (95 % CI) Lin's concordance correlation coefficient was 0.79 (0.62-0.89), effectively simulating a Core Laboratory scenario. We provide an initial validation of cross-sectional volumetric aortic atheroma assessment using CTA. This proposed methodology highlights the potential for utilizing non-invasive aortic plaque imaging for risk prediction across a range of clinical scenarios.

Quantification of Retrograde Blood Flow in the Descending Aorta Using Transesophageal Echocardiography in Comparison to 4D Flow MRI

BACKGROUND

Retrograde diastolic blood flow in the proximal descending aorta (DAo), which connects plaques ≥4 mm thickness with brain-supplying arteries, has previously been identified as a possible source of brain embolism. Currently, only 4D flow MRI is able to visualize and quantify potential retrograde embolization pathways in the DAo in-vivo. Hence, it was our aim to test if the extent of retrograde flow could be estimated by routine 2D transesophageal echocardiography (TEE).

METHODS

Forty-eight acute stroke patients were prospectively included and they underwent Doppler examinations of the transition zone between the aortic arch and the DAo using a 20 mm 2D sample volume in longitudinal section at 90-140° Doppler angle during routine TEE. Velocity-time-integrals (VTI) were studied for antegrade and retrograde velocities and the ratio (VTIratio) was calculated and correlated with the length of retrograde pathlines at that site, which were visualized using 4D flow MRI at 3-Tesla. A receiver operating characteristic (ROC) curve was used to evaluate a threshold value of VTIratio in differentiating large (≥3 cm) from small (<3 cm) retrograde flow extent.

RESULTS

At the TEE measurement site, the mean VTIratio was 0.53 ± 0.16 and the mean length of retrograde pathlines reaching back into the aortic arch was 3.1 ± 1.4 cm. VTIratio was an independent predictor of retrograde pathline length (r = 0.44; p = 0.002). ROC analysis identified a VTIratio threshold value of 0.6012 with a sensitivity of 0.5, a specificity of 0.92, and positive and negative predictive values of 0.84 and 0.68, respectively. Accordingly, 11 (22.91%) patients had a VTIratio cutoff value ≥0.6012 and corresponding retrograde pathline length ≥3 cm in 4D flow MRI.

CONCLUSIONS

TEE allows predicting the length of retrograde pathlines. Hence, it may offer a cost-effective way to investigate independent predictors of DAo flow reversal in large-scale studies. However, TEE is only of limited value as a screening tool for high retrograde flow in a clinical setting, as only ∼23% of patients can be spared 4D flow MRI, which remains indispensable for the exact assessment of individual embolization pathways from plaques of the DAo in-vivo.

Increasing severity of aortic atherosclerosis in coronary artery bypass grafting patients evaluated by transesophageal echocardiography

Background

Atherosclerotic disease in coronary artery bypass grafting (CABG) patients is a potential contributor to complications in the perioperative periods. This study was undertaken to better define how the frequency of aortic atheromatous disease among patients coming for CABG has evolved over the last decade.

Methods

Data from elective patients coming for CABG who underwent transesophageal echocardiography (TEE) examinations following induction of anesthesia were obtained for the years 2002 and 2009. Aortas were graded according to the method of Kronzon, with the following interpretations: normal = grade I, intimal thickening = 2, atheroma of less than 5 mm = 3, atheroma of > 5 mm = 4, and any mobile atheroma = 5. The data of 124 patients who underwent comprehensive exam of the aorta by one cardiac anesthesiologist were gathered and assigned into two groups based on the year TEE was done. Student’s t-test was used for statistical analysis. A P value < 0.05 was considered significant. The data were presented as mean ± SD.

Results

There was significant difference between group 2002 (2.05 ± 1.28) and group 2009 (2.59 ± 1.11) in atheroma grade (P = 0.013).

Conclusions

Patients coming for CABG in group 2009 exhibited significantly higher grades of aortic atheroma on TEE, compared to group 2002. Understanding the risk of atheroma in the elderly CABG population may help in altering surgical approaches to lessen the risk of catastrophic stroke. Potential options needing further study include the off-pump approach and modification of cross-clamp site and technique as well as other modalities.

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.

Detecting atheromatous plaques in the aortic arch or supra-aortic arteries for more accurate stroke subtype classification

INTRODUCTION

To investigate the correlations of atheromatous plaques in the aortic arch or supra-aortic arteries with intracranial arterial stenosis and carotid plaques in stroke patients, and to determine whether taking these plaques into account will reduce the proportion of patients in the undetermined etiology group.

METHODS

We prospectively enrolled 308 ischemic stroke patients, whose clinical characteristics and A-S-C-O classifications were compared with analyses of intracranial arteries, carotid arteries, aortic arch, and supra-aortic arteries.

RESULTS

125(40.6%) patients had plaques in the aortic arch or supra-aortic arteries, of which 106 (84.8%) had complex plaques. No correlations were observed between these plaques and carotid plaques ( p = 0.283) or intracranial arterial stenosis ( p = 0.097). After detecting the mobile thrombi in the aortic arch and supra-aortic arteries, the proportion of patients in the atherothrombosis group was increased from 33.8% to 55.5% ( p = 0.00), whereas the proportion of patients in stroke of undetermined etiology group was decreased from 19.2% to 11.0% ( p = 0.00).

DISCUSSION

Examining only the carotid and intracranial arteries may not provide adequate information about large arteries in stroke patients. Therefore, it would be better to include a search for relevant plaques in the aortic arch or supra-aortic arteries in modern stroke workup, for it may lead to more accurate stroke subtype classification and guide secondary prevention.

Complex atheromatous plaques in the descending aorta and the risk of stroke: a systematic review and meta-analysis

BACKGROUND AND PURPOSE

Proximal aortic plaques, especially in the aortic arch, have already been established as an important cause of stroke and peripheral embolism. However, aortic plaques situated in the descending thoracic aorta have recently been postulated as a potential embolic source in patients with cryptogenic cerebral infarction through retrograde aortic flow. The aim of the present study was to evaluate the potential association of descending aorta atheromatosis with cerebral ischemia.

METHODS

We conducted a systematic review and meta-analysis of all available prospective observational studies reporting the prevalence of complex atheromatous plaques in the descending aorta in patients with stroke and in unselected populations undergoing examination with transesophageal echocardiography.

RESULTS

We identified 11 eligible studies including a total of 4000 patients (667 patients with stroke and 3333 unselected individuals; mean age, 65 years; 55% men). On baseline transesophageal echocardiograpic examination, the prevalence of complex atheromatous plaques in the descending aorta was higher (P=0.001) in patients with stroke (25.4%; 95% confidence interval, 14.6-40.4%) compared with unselected individuals (6.1%; 95% confidence interval, 3.4-10%). However, no significant difference (P=0.059) in the prevalence of complex atheromatous plaques in the descending aorta was found between patients with cryptogenic (21.8%; 95% confidence interval, 17.5-26.9%) and unclassified (28.3%; 95% confidence interval, 23.9-33.1%) cerebral infarction.

CONCLUSIONS

Our findings indicate that the presence of complex plaques in the descending aorta is presumably a marker of generalized atherosclerosis and high vascular risk. The present analyses do not provide any further evidence for a direct causal relationship between descending aorta atherosclerosis and cerebral embolism.

Ischemic lesion burden and characteristics of aortic atheroma

BACKGROUND

To investigate whether ischemic lesion burden including lesion pattern, number, and volume would vary depending on risk stratification of aortic atheroma (AA).

METHODS

Acute stroke patients were enrolled if they had (1) acute ischemic lesions on diffusion-weighted imaging within 5 days of symptom onset, (2) cardioembolic stroke established through extensive workup, and (3) only ascending or arch AA detected by transesophageal echocardiography as an embolic source. AA was classified as complex (protruding ≥4 mm into the aortic lumen or any mobile or ulcerative component) or simple (<4 mm).

RESULTS

Eighty-one patients (male: 65.4% and age: 66.7 ± 11.0 years) were included in the study. Thirty-four patients (41.9%) had complex atheroma. These patients had a greater number of ischemic lesions (median: 2 lesions [range: 1-42] versus one lesion [range: 1-27], P = .017) and a larger infarct size (9.01 cc [range: 3.58-49.14] versus 4.6 cc [range: 2.3-13.28), P = .056) than the simple atheroma group. Multivariable logistic regression analysis showed that ischemic lesion volume was independently associated with complex atheroma (odds ratio: 1.03, 95% confidence interval: 1.002-2.148, P = .035), while multiple lesions were related (odds ratio: 3.03, 95% confidence interval: .88-10.42, P = .079).

CONCLUSIONS

Ischemic lesion burden in patients with AA differed according to AA characteristics, suggesting that the morphological features of AA could reflect an embolic potential of AA.