Complex atheromatosis of the aortic arch in cerebral infarction

In many stroke patients it is not possible to establish the etiology of stroke. However, in the last two decades, the use of transesophageal echocardiography in patients with stroke of uncertain etiology reveals atherosclerotic plaques in the aortic arch, which often protrude into the lumen and have mobile components in a high percentage of cases. Several autopsy series and retrospective studies of cases and controls have shown an association between aortic arch atheroma and arterial embolism, which was later confirmed by prospectively designed studies. The association with ischemic stroke was particularly strong when atheromas were located proximal to the ostium of the left subclavian artery, when the plaque was ≥ 4 mm thick and particularly when mobile components are present. In these cases, aspirin might not prevent adequately new arterial ischemic events especially stroke. Here we review the evidence of aortic arch atheroma as an independent risk factor for stroke and arterial embolism, including clinical and pathological data on atherosclerosis of the thoracic aorta as an embolic source. In addition, the impact of complex plaques (≥ 4 mm thick, or with mobile components) on increasing the risk of stroke is also reviewed. In non-randomized retrospective studies anticoagulation was superior to antiplatelet therapy in patients with stroke and aortic arch plaques with mobile components. In a retrospective case-control study, statins significantly reduced the relative risk of new vascular events. However, given the limited data available and its retrospective nature, randomized prospective studies are needed to establish the optimal secondary prevention therapeutic regimens in these high risk patients.     

主动脉弓粥样硬化斑块与卒中

主动脉弓粥样硬化斑块是栓塞性卒中的原因之一.随着对主动脉弓斑块研究的深入.其与卒中的关系也越来越清楚,尤其是主动脉弓斑块厚度≥4 mm与原因不明性卒中、卒中复发以及其他血管事件有关.虽然对主动脉弓斑块与卒中的临床特点有了进一步的了解,但仍然存在许多疑问.     

Aortic source of brain embolism

Opinion statement Aortic arch atheroma has more recently been identified as an independent risk factor for ischemic stroke. Initially, this was a result of careful autopsy observations, then followed by a series of in vivo studies in which aortic arch atheroma was identified by transesophageal echocardiography. The association of aortic arch atheroma with ischemic stroke is most likely causal, given that the stroke risk increases with increasing thickness of arch atheroma. There is quite a sharp increase in stroke risk for atheroma of 4 mm or greater compared with lesser thicknesses. The clinical diagnosis is suggested when transient ischemic attack or ischemic stroke has occurred in which no obvious cardiac or arterial source of embolism is found. The presence of aortic arch atheroma is usually detected by transesophageal echocardiography and sometimes by magnetic resonance imaging or computed tomography. There is uncertainty about clinical management, particularly for secondary prevention. Options include the use of antiplatelet agents, anticoagulants, thrombolysis, or surgery. The latter two options have only been described rarely in case reports. Of the less invasive approaches, combination antiplatelet therapy with aspirin and clopidogrel is favored, or the use of warfarin. The Aortic arch Related Cerebral Hazard (ARCH) trial is being conducted to determine which of these is more effective in minimizing a composite outcome cluster of ischemic stroke, intracranial hemorrhage, myocardial infarction, peripheral embolism, or vascular death. Other more general management strategies should include reasonably aggressive risk factor control with blood pressure and lipid-lowering therapies and, if indicated, careful diabetic control.     

Splenic and mesenteric emboli in a patient with protruding aortic arch atheroma

Protruding atheromas in the thoracic aorta are an important cause of embolic disease. Transesophageal echocardiography (TEE) is the modality of choice for diagnosis of these lesions. We present a patient with splenic infarction in whom TEE revealed a large mobile atheroma in the aortic arch. A few hours following the disappearance of this mass from the aortic arch, the patient developed mesenteric artery embolism requiring subtotal small-bowel resection. We discuss the importance of the aortic arch as a source of peripheral emboli and the treatment modalities in these patients.     

Atheromas of the thoracic aorta: clinical and therapeutic update

Atherosclerotic lesions of the thoracic aorta have recently been recognized as an important cause of stroke and peripheral embolization, which may result in severe neurologic damage as well as multiorgan failure and death. Their prevalence is approximately 27% in patients with previous embolic events. Transesophageal echocardiography is the modality of choice for the diagnosis of these atheromas, although computed tomography, magnetic resonance imaging and intraoperative epiaortic ultrasound are complementary. Two clinical syndromes account for the embolic phenomena, atheroemboli and, more commonly, thromboemboli. In addition to such superimposed thrombi, plaque thickness (especially > or =4 mm) also correlates with embolic risk. This risk is high, with 12% of patients having a recurrent stroke within approximately one year, and up to 33% of patients having a stroke or peripheral embolus. In addition, aortic atheromas (as seen with intraoperative transesophageal echocardiography and intraoperative epiaortic ultrasound) are an important cause of stroke during heart surgery requiring cardiopulmonary bypass. Such strokes occur during approximately 12% of cardiac operations employing cardiopulmonary bypass when aortic arch atheromas are seen with transesophageal echocardiography (six times the general intraoperative stroke rate). Although anticoagulant strategies have been reported with encouraging results in nonrandomized studies, prospective, randomized data must be developed before an effective and safe treatment strategy can be determined. This review details the current state of knowledge in this area, including the clinical and pathologic evidence that thoracic aortic atherosclerosis is an important embolic source, data which guide current therapy and future directions for clinical investigation.     

Aortic atherosclerosis is a marker for significant coronary artery disease

Atherosclerosis is a generalized process that may involve the entire vasculature as well as the coronary arteries. Aortic atherosclerosis (AA) is associated with an increased risk for recurrent ischemic stroke and cardiovascular death and can be diagnosed by transesophageal echocardiography (TEE). We performed TEE in 60 patients (47 men and 13 women; age range 37-78, mean 53.5 +/- 9.9) who underwent coronary angiography, to assess whether atherosclerosis in the thoracic aorta correlates with coronary artery disease (CAD) or may be a marker for it. Significant CAD was defined as either > 50% reduction of internal diameter of the left main coronary artery or > 70% reduction of the internal diameter in the anterior descending, right coronary or circumflex artery. The number of diseased vessels was based on the Coronary Artery Surgery Study criteria. A grading system was used to detect AA. The thoracic aorta was considered to be normal and classified as grade I when the internal surface was smooth and without lumen irregularities or increased echo-intensity. Grade II changes consisted of increased echodensity of the intima without lumen irregularity or thickening. Grade III changes consisted of increased echodensity of intima with well defined atheroma extending < 3 mm in the aorta. Grade IV and V changes consisted of atheroma > 3 mm and protruding mobile plaques, respectively. Grades III-V were considered as AA. Twenty two of the 29 patients (75.9%) with CAD and 10 of the 31 patients (32.3%) without CAD had AA detected by TEE. There was a significant relationship between CAD and AA (r = 0.44, p < 0.001). The sensitivity and specificity of AA in detecting CAD were 75.9% and 67.7%, respectively. Our data suggest that AA is common in patients with significant CAD. Detection of AA by TEE may be a marker for CAD and early detection of aortic atherosclerosis may contribute to diagnostic and therapeutic interventions and thereby improve the prognosis.     

Retrograde embolism from the descending thoracic aorta causing stroke: An underappreciated clinical condition

The mechanism of retrograde aortic blood flow is a complex and underreported clinical phenomenon. Complex plaques of the aortic arch are considered high-risk sources of cerebral emboli.¹ Aortic plaques situated in the descending thoracic aorta are however often overlooked and in fact can be more frequent potential sources of cerebral embolism through the mechanism of retrograde aortic blood flow. We present the case of an elderly Caucasian female who experienced recurrent posterior circulation embolic strokes where the only possible underlying etiology was found to be an atheroma in the descending thoracic aorta, possibly showering retrograde emboli.     

Multiple cerebral emboli following dislocation and retraction of a partially deployed CoreValve prosthesis during transcatheter aortic valve implantation

Transcatheter aortic valve implantation for patients with severe aortic stenosis at a high‐operative risk has been demonstrated to improve mortality compared to standard medical therapy. Registry data and the PARTNER trial have shown a significant risk of stroke (3–5%) following the procedure. Studies using cerebral diffusion‐weighted magnetic resonance imaging have suggested the mechanism of stroke to be multiple small embolic infarcts, possibly from aortic atheroma dislodged during the movement of the valve and its apparatus around the thoracic aorta. The incidence of these infarcts is higher than clinically apparent. The Medtronic CoreValve (Medtronic, Minneapolis, Minnesota) prosthesis is a self‐expanding nitinol frame with porcine valve, whose deployment is achieved by the retraction of the delivery catheter. Potential complications of this method include valve mal‐positioning and dislocation. The partially deployed valve may then be resheathed following retraction back into the descending aorta and subsequently redeployed. We present two such cases with evidence of both “silent” and clinically evident cerebral infarction. © 2013 Wiley Periodicals, Inc.     

Aortic Tumor or Mobile Thrombus?

Isolated large mobile mass in the thoracic aorta can be due to thrombus or, rarely, aortic tumor. We report the case of a 61‐year‐old man with no history of medical problems presenting with neurologic deficits and in whom a large mobile echogenic mass in the distal aortic arch was found with transesophageal echocardiography. Given his few cardiovascular risk factors and absence of other systemic symptoms, he received anticoagulant therapy. Subsequent resolution of the aortic mass suggested a diagnosis of thrombus. This case illustrates an unusual manifestation of aortic arch atherosclerosis and underscores the utility of transesophogeal echocardiography for patients with ischemic stroke. (Echocardiography 2010;27:E21‐E22)     

Hyperinsulinemia is an independent predictor for complex atherosclerotic lesion of thoracic aorta in non-diabetic patients

OBJECTIVE: Hyperinsulinemia is a well known risk factor for cardiovascular event. However, it is not known whether hyperinsulinemia facilitates atherosclerotic complex lesions of aorta in non-diabetic patients. We investigated whether hyperinsulinemia is an independent marker of severity of atherosclerosis in thoracic aorta of non-diabetic patients using multiplane transesophageal echocardiography (TEE). RESEARCH DESIGN AND METHODS: Non-diabetic 90 patients with cardiovascular disease underwent TEE, and were analyzed for plasma insulin levels of oral glucose tolerance test, conventional atherosclerotic risk factors and coronary angiographic features. RESULTS: Thoracic aortic plaques were detected in 84 patients (93%). The complex atherosclerotic lesions were observed in 35 (39%) patients, most frequently at the part of aortic arch (p<0.005), showing the greatest atheroma score in thoracic aorta (p<0.05). Univariate analysis showed age, male gender, smoking, coronary artery disease, HDL-cholesterol, insulin levels in glucose tolerance test and homeostasis model assessment insulin resistance index (HOMA index) were found to be significant predictors of complex atherosclerotic lesions. Multivariate regression analysis revealed that HOMA index was an independent predictor of complex atherosclerotic lesions (odds ratio 1.93, p=0.006). There was a significant positive correlation between HOMA index and the atheroma score of thoracic aorta (p<0.001). CONCLUSIONS: Hyperinsulinemia is an independent predictor of complex atherosclerotic lesions detected by TEE in the thoracic aorta of non-diabetic patients.     

Routine transesophageal echocardiography for the evaluation of cerebral emboli in elderly patients

BACKGROUND: Approximately 20% of cerebral infarctions are cardioembolic in nature. Transesophageal echocardiography (TEE) is widely regarded as the initial study of choice for evaluating cardiac source of embolism. Although the majority of cerebrovascular accidents occur in elderly patients, the value of TEE in this population is poorly defined. METHODS: We compared 491 patients older than 65 years with suspected embolic stroke or transient ischemic attack (TIA) who had undergone TEE evaluation between April 2000 and February 2004 to an age-, sex-, and time-matched control group that consisted of 252 patients. Studies were reviewed for abnormalities associated with thromboembolic disease. RESULTS: The overall incidence of stroke risk factors was significantly higher in the study than in the control group. However, the four patients with left atrial thrombi had a history of atrial fibrillation. Although ascending and aortic arch sessile atheromata were observed more frequently in the study than control group, there were no significant differences in the incidence of either complex or mobile aortic atheromata. The incidence of atrial septal aneurysm was higher in the stroke/TIA group, but not in association with patent foramen ovale. Finally, there were also no differences in the incidence of spontaneous echocontrast, and/or patent foramen ovale between study and control groups. CONCLUSIONS: We conclude: (1) There is a higher incidence of abnormalities implicated as sources of thromboembolic disease on TEE in elderly patients with cerebral infarctions, but (2) this incidence is driven by the presence of sessile aortic atheroma and atrial septal aneurysm. Until the benefits of specific therapies for these conditions are known, routine TEE in elderly patients with suspected embolic neurological events appears to be unwarranted.     

Protruding aortic atheromas predict stroke in elderly patients undergoing cardiopulmonary bypass: experience with intraoperative transesophageal echocardiography.

Protruding atheromas of the aortic arch identified by transesophageal echocardiography have been implicated as a cause of stroke in elderly patients. One hundred thirty patients greater than or equal to 65 years of age were studied with intraoperative transesophageal echocardiography to detect aortic arch protruding atheromas and determine if these patients were at higher risk for perioperative stroke. Protruding atheromas were identified in 23 (18%) of 130 patients. In 19 (83%) of these 23 patients, palpation of the aortic arch at operation did not identify significant abnormalities. Five patients (4%) had perioperative stroke. Logistic regression identified aortic arch atheroma as the only historical or procedural variable that was predictive of stroke (odds ratio 5.8, 95% confidence interval 1.2 to 27.9, p less than 0.03). A history of peripheral or cerebrovascular disease, presence of aortic calcification, cardiac risk factors, age and duration of cardiopulmonary bypass did not predict stroke. In contrast, patients with protruding atheromas with mobile components were at highest risk. There were 3 (25%) of 12 patients with a mobile atheroma who had a stroke versus 2 (2%) of 118 patients without a mobile atheroma (chi-square = 10.3, p = 0.001). Displacement and detachment of the frail, protruding atherosclerotic material by aortic arch cannulation or by the high pressure jet emanating from the cannula tip may play an important role in the creation of embolization and stroke.     

Echocardiographic risk stratification for ischemic stroke in non‐rheumatic atrial fibrillation: Importance of aortic plaques detected by transesophageal echocardiography*

Background: The aim of the present paper was to assess the prevalence of atherosclerotic aortic plaques in non‐rheumatic atrial fibrillation and their relation to ischemic stroke. Although aortic plaques are frequently seen in the elderly, their significance remains unclear in relation to ischemic stroke in patients with atrial fibrillation. Methods: Transesophageal echocardiography was performed on 56 patients (age 61 ± 10 years) with atrial fibrillation. The aorta was divided into two segments (i.e. the proximal aorta that includes the ascending aorta and the aortic arch proximal to the ostium of the left subclavian artery, and the distal aorta that is the descending aorta distal to the left subclavian artery). Thickened intima = 3 mm in thickness was defined as aortic plaques. Results: Ischemic stroke was found in 14 of the 56 patients. Aortic plaques were detected in 25 of the 56 patients. All of these 25 patients had aortic plaques in the proximal aorta, and 17 of them also had aortic plaques in the distal aorta. Ischemic stroke was found in 11 of the 25 patients (44%) with aortic plaques, and three of the 31 patients (10%) without aortic plaques (P < 0.01). Conversely, aortic plaques were detected in 11 of the 14 patients (79%) with ischemic stroke, and in 14 of the 42 patients (33%) without (P < 0.01). The patients with ischemic stroke had a larger left atrium (47 ± 5 vs 43 ± 6 mm; P < 0.05) than those without. Aortic plaques were a correlate only of previous ischemic stroke (P < 0.05) by multiple logistic regression analysis. Conclusions: Atherosclerotic aortic plaques detected by transesophageal echocardio‐graphy are a correlate of previous ischemic stroke in patients with non‐rheumatic atrial fibrillation.     

Mobile Aortic Atheroma and Systemic Emboli: Efficacy of Anticoagulation and Influence of Plaque Morphology on Recurrent Stroke

Objectives. We sought to determine the influence of plaque morphology and warfarin anticoagulation on the risk of recurrent emboli in patients with mobile aortic atheroma.Background. An epidemiologic link between aortic atheroma and systemic emboli has been described both in pathologic and transesophageal studies. Likewise, a few studies have found an increased incidence of recurrent emboli in these patients. The therapeutic implications of these findings has not been studied.Methods. Thirty-one patients presenting with a systemic embolic event and found to have mobile aortic atheroma were studied. The height, width and area of both immobile and mobile portions of atheroma were quantitated. The dimensions of the mobile component was used to define three groups: small, intermediate and large mobile atheroma. The patients were followed up by means of telephone interview and clinical records, with emphasis on anticoagulant use and recurrent embolic or vascular events.Results. Patients not receiving warfarin had a higher incidence of vascular events (45% vs. 5%, p = 0.006). Stroke occurred in 27% of these patients and in none of those treated with warfarin. The annual incidence of stroke in patients not taking warfarin was 0.32. Myocardial infarction occurred in 18% of patients also in this group. Taken together, the risk of myocardial infarction or stroke was significantly increased in this group (p = 0.001). Forty-seven percent of patients with small, mobile atheroma did not receive warfarin. Recurrent stroke occurred in 38% of these patients, representing an annual incidence of 0.61. There were no strokes in patients with small, mobile atheroma treated with warfarin (p = 0.04). Likewise, none of the patients with intermediate or large mobile atheroma had a stroke during follow-up. Only three of these patients had not been taking warfarin.Conclusions. Patients presenting with systemic emboli and found to have mobile aortic atheroma on transesophageal echocardiography have a high incidence of recurrent vascular events. Warfarin is efficacious in preventing stroke in this population. The dimension of the mobile component of atheroma should not be used to determine the need for anticoagulation.     

Cardioembolic stroke

Cardiac sources of emboli account for over one quarter of all ischemic strokes. Strokes due to cardioembolism are in general severe and prone to early and long-term recurrence. Nonvalvular atrial fibrillation remains the most common cause of cardioembolic stroke. Despite the proven efficacy of oral anticoagulation, it is prescribed for less than half of the patients with risk factors for embolism and no contraindications for anticoagulation. The embolic risk of patent foramen ovale is low except when combined with an atrial septal aneurysm. Aortic arch atheroma as an independent risk factor for ischemic stroke is the subject of ongoing debate. As the risk of embolism is heterogeneous for the various potential cardioembolic conditions, accurate definition of stroke mechanism is very important to guide the most effective therapy.     

Mobile atheromatous plaque of the aortic arch diagnosed by transthoracic echocardiography prior to coronary artery bypass surgery

A routine pre-operative chest X-ray of a patient admitted to our institution for an elective coronary artery bypass operation revealed a mildly dilated mediastinal silhouette, which led the cardiovascular surgery resident to schedule emergency transthoracic echocardiography (TTE), with a special note asking for detailed evaluation of the ascending aorta and aortic arch. TTE revealed a mobile atheroma at the aortic arch, which obliged the cardiac surgery team to modify their strategy to combined hemi-arcus aortae replacement and coronary artery bypass grafting (CABG). Although with transoesophageal echocardiography (TEE) a small portion of the ascending aorta may be obscured by the trachea, TEE provides higher resolution images than TTE. Therefore one can conclude that TEE is the imaging modality of choice for detecting aortic atheromatous plaques but in patients with low risk for stroke and aortic atheromas, a detailed TTE may be sufficient for the pre-operative assessment.     

Risk factors for impaired neurological outcome after thoracic aortic surgery

BackgroundWe aimed to identify risk factors for an impaired postoperative neurological outcome after thoracic aortic surgery.MethodsData from all patients undergoing thoracic aortic surgery between 2010 and 2020 at our institution were collected and analyzed retrospectively. Logistic regression analysis was used to identify independent risk factors for permanent postoperative neurological deficit (ND) (stroke), which was defined as a ND lasting at least seven days.ResultsThoracic aortic surgery was performed in 1,334 patients. Of these, 286 (21.4%) underwent emergency surgery. The mean EuroSCORE II was 8.6±10.1. A perioperative stroke occurred in 94 patients (7.0%). Of all strokes, 62.8% (n=59) were considered of embolic and 24.5% (n=23) of hemodynamic origin. In elective procedures, stroke rates ranged from 0.5% after valve-sparing root replacement to 8.1% after arch surgery. Adjusted logistic regression identified advanced age [>70 years; odds ratio (OR), 1.83; P=0.009], acute type A dissection (ATAD) (OR, 1.69; P=0.0495), aortic arch surgery (OR, 3.24; P<0.001), concomitant coronary artery bypass grafting (CABG) (OR, 2.19; P=0.005), and high extracorporeal circulation (ECC) time (>230 min; OR, 1.70; P=0.034) as independent risk factors for all strokes. Secondary endpoint analyses revealed that risk factors for hemodynamic stroke were arch surgery, advanced age (>70 years), atherosclerosis, and ATAD. Risk factors for embolic stroke were arch surgery, concomitant CABG and preoperative cerebral malperfusion.ConclusionsIdentified independent risk factors for all strokes were advanced age, ATAD, arch surgery, concomitant CABG, and high ECC time. Hemodynamic and embolic strokes show distinct risk profiles.     

Racial differences in aortic atheroma in patients undergoing transesophageal echocardiography for unexplained stroke or transient ischemic attack

Racial differences in the prevalence of complex thoracic aortic atheroma were evaluated in 318 patients referred for transesophageal echocardiography after unexplained stroke or transient ischemic attack. African-Americans were found to have fewer complex thoracic aortic atheroma and fewer combined cardiac sources of embolus than Caucasian patients. This finding persists after adjusting for racial differences in atherosclerotic risk factors.     

Effect of treatment on the incidence of stroke and other emboli in 519 patients with severe thoracic aortic plaque

Severe aortic plaques seen on transesophageal echocardiography (TEE) are a high-risk cause of stroke and peripheral embolization. Evidence to guide therapy is lacking. Retrospective information was obtained regarding the occurrence of embolic events (stroke, transient ischemic attacks, or peripheral emboli) in 519 patients with severe thoracic aortic plaque seen on TEE since 1988. Treatment with statins, warfarin, or antiplatelet medications was noted. Treatment was not randomized. In a matched-paired analysis, each patient taking each class of therapy was matched for age, gender, previous embolic event, hypertension, diabetes, congestive failure, and atrial fibrillation to someone not taking that medication. Multivariate analysis was also performed. An embolic event occurred in 111 patients (21%). Multivariate analysis showed that statin use was independently protective against recurrent events (p = 0.0001). Matched analysis also showed a protective effect of statins (p = 0.0004; absolute risk reduction 17%, relative risk reduction 59%, number needed to treat [n = 6]). No protective effect was found for warfarin or antiplatelet drugs. The odds ratio for embolic events was 0.3 (95% confidence interval [CI] 0.2 to 0.6) for statin therapy, 0.7 (95% CI 0.4 to 1.2) for warfarin, and 1.4 (95% CI 0.8 to 2.4) for antiplatelet agents. Thus, there is a protective effect of statin therapy, and no significant benefit of warfarin or antiplatelet drugs on the incidence of stroke and other embolic events in patients with severe thoracic aortic plaque on TEE.     

Protruding atheromas in the thoracic aorta and systemic embolization

OBJECTIVE: To determine whether protruding atheromas in the thoracic aorta are a risk factor for systemic embolization. DESIGN: Case-control study. SETTING: A referral hospital. PATIENTS: A total of 122 patients with a history of stroke, transient ischemic attack, or peripheral emboli and an equal number of age- and sex-matched control patients. MEASUREMENTS: Evaluation using transesophageal echocardiography was done in case patients to detect protruding atheromas in the thoracic aorta and in control patients for cardiac indications other than emboli. MAIN RESULTS: Matched logistic regression showed that the presence of protruding atheromas was strongly related to the occurrence of embolic symptoms (odds ratio, 3.2; 95% Cl, 1.6 to 6.5; P less than 0.001). Furthermore, atheromas with mobile components were present only in case patients. When known risk factors for stroke (hypertension and diabetes) were added to the model, the presence of protruding atheromas remained an independent risk factor for embolic symptoms (odds ratio, 3.8). Hypertension was also independently associated with embolic symptoms (odds ratio, 2.7), but diabetes was not (odds ratio, 1.0). CONCLUSION: Protruding atheromas in the thoracic aorta can be detected by transesophageal echocardiography and should be considered as a cause of strokes, transient ischemic attacks, and peripheral emboli.