Detection of Left Ventricular Thrombus by Cardiac Magnetic Resonance in Embolic Stroke of Undetermined Source

Left Ventricular Injury Detected by Cardiac MRI and Incident Ischemic Stroke and Dementia Risk: The Multi-Ethnic Study of Atherosclerosis

BACKGROUND AND OBJECTIVES

Left ventricular injury (LVI) can be detected by cardiac magnetic resonance (CMR) imaging with high sensitivity; however, the implication of these findings on brain health longitudinally is uncertain. We aimed to evaluate the association between LVI biomarkers detected by CMR and the risk of developing ischemic stroke and dementia.

METHODS

We analyzed the prospective, observational cohort of participants in the Multi-Ethnic Study of Atherosclerosis (MESA) study (median follow-up of 8.7 years). MESA is a population-based cohort recruited from 6 communities. The complete case analysis (CCA) sample included stroke-free participants who underwent CMR at Exam 5 (2010-2012). The multiple imputation (MI) sample consisted of stroke-free participants at Exam 5, irrespective of CMR collection. Missing CMR variables were imputed because of the nonrandom missingness of CMR data. The primary exposure was LVI defined by LV ejection fraction < 50% or circumferential strain ≥ -10 in any LV apical wall. Secondary exposures were left ventricular ejection fraction (LVEF) and strain as continuous measures. Primary outcomes were (1) incident ischemic stroke and (2) newly diagnosed all-cause dementia. Cox proportional hazard models were adjusted for demographic and clinical covariates.

RESULTS

There were 2,584 (11.7% with LVI [mean age 71, 65% male], 88.3% without LVI [mean age 69, 44% male]) and 4,594 participants in the CCA and MI cohorts, respectively. Incident ischemic stroke occurred in 18 (6%) participants with and 65 (3%) without LVI in the CCA sample (302 or 12% with and 18 or 6% without LVI in the MI sample). Both groups had similar rates of cardiovascular disease (6% vs 4%, p = 0.143). LVI was significantly associated with incident ischemic stroke in the MI cohort (adjusted hazard ratio [HR] 1.82, 95% CI 1.08-3.09), but not in the CCA cohort. LV apical peak strain was significantly associated with newly diagnosed dementia only in the MI cohort (adjusted HR 1.06, 95% CI 1.01-1.12). LVEF per 10% was significantly associated with newly diagnosed dementia in both cohorts (adjusted HR in MI cohort 0.73, 95% 0.59-0.90).

DISCUSSION

CMR-detected LVI is associated with incident ischemic stroke and newly diagnosed dementia. Further studies are needed to validate CMR biomarkers of brain injury risk.

Left ventricular disease as a risk factor for adverse outcomes and stroke recurrence in patients with embolic stroke of undetermined source

BACKGROUND

Severe left ventricular (LV) systolic dysfunction (ejection fraction [EF] < 30%) is a known cardiovascular risk factor and a major cause of cardioembolism. However, less severe forms of LV disease (LVD), such as mild-to-moderate LV dysfunction and LV wall motion abnormalities (LVWMAs), are considered potential minor cardiac sources in Embolic Stroke of Undetermined Source (ESUS), but their role is underexplored. This study aims to evaluate the prevalence of LVD in ESUS and its association with adverse vascular events and mortality.

METHODS

Retrospective, single-center study including consecutive ESUS patients admitted from January 2016 to May 2024. LVD was defined as either global systolic dysfunction (LV ejection fraction 30%-49%) or regional LVWMAs, unrelated to acute or recent (within 4 weeks) myocardial infarction. Univariate and multivariate Cox regression analyses evaluated the association of LVD with a primary composite outcome (including ischemic stroke recurrence, acute coronary events, and all-cause mortality), and its components separately.

RESULTS

Among the 556 ESUS patients (median age 71 years [IQR 60-80], 44.6% female), 95 (17.1%) had LVD, including 51 (53.7%) with reduced LVEF (30%-49%), and 81 (85.3%) presenting LVWMAs. During follow-up (median 30 months), LVD(+) patients had significantly higher rates of the composite outcome (41.0% vs 21.3%, p < 0.001), ischemic stroke recurrence (13.7% vs 5.9%, p = 0.007), acute coronary events (7.4% vs 2.4%, p = 0.012), and all-cause mortality (28.4% vs 15.2%, p = 0.002), compared to LVD(-) patients. Multivariate Cox regression analysis showed that LVD independently increased the risk of ischemic stroke recurrence (adjusted HR 2.13, 95%CI 1.08-4.24, p = 0.032) and the composite outcome (aHR 1.92, 95%CI 1.27-2.90, p = 0.002), but not acute coronary events (aHR 1.65; 95%CI 0.54-5.01, p = 0.374), or all-cause mortality (aHR 1.62; 95%CI 0.98-2.70, p = 0.062).

CONCLUSIONS

LVD is significantly associated with an increased risk of ischemic stroke recurrence and adverse outcomes in ESUS patients. These findings highlight the clinical importance of identifying and optimizing LVD management among ESUS to improve long-term outcomes in this population.

Stasis imaging predicts the risk of cardioembolic events related to acute myocardial infarction: the ISBITAMI study

INTRODUCTION AND OBJECTIVES

In the setting of ST-segment elevation myocardial infarction (STEMI), imaging-based biomarkers could be useful for guiding oral anticoagulation to prevent cardioembolism. Our objective was to test the efficacy of intraventricular blood stasis imaging for predicting a composite primary endpoint of cardioembolic risk during the first 6 months after STEMI.

METHODS

We designed a prospective clinical study, Imaging Silent Brain Infarct in Acute Myocardial Infarction (ISBITAMI), including patients with a first STEMI, an ejection fraction ≤ 45% and without atrial fibrillation to assess the performance of stasis metrics to predict cardioembolism. Patients underwent ultrasound-based stasis imaging at enrollment followed by heart and brain magnetic resonance at 1-week and 6-month visits. From the stasis maps, we calculated the average residence time, RT, of blood inside the left ventricle and assessed its performance to predict the primary endpoint. The longitudinal strain of the 4 apical segments was quantified by speckle tracking.

RESULTS

A total of 66 patients were assigned to the primary endpoint. Of them, 17 patients had 1 or more events: 3 strokes, 5 silent brain infarctions, and 13 mural thromboses. No systemic embolisms were observed. RT (OR, 3.73; 95%CI, 1.75-7.9; P<.001) and apical strain (OR, 1.47; 95%CI, 1.13-1.92; P=.004) showed complementary prognostic value. The bivariate model showed a c-index=0.86 (95%CI, 0.73-0.95), a negative predictive value of 1.00 (95%CI, 0.94-1.00), and positive predictive value of 0.45 (95%CI, 0.37-0.77). The results were confirmed in a multiple imputation sensitivity analysis. Conventional ultrasound-based metrics were of limited predictive value.

CONCLUSIONS

In patients with STEMI and left ventricular systolic dysfunction in sinus rhythm, the risk of cardioembolism may be assessed by echocardiography by combining stasis and strain imaging. Registered at ClinicalTrials.gov (NCT02917213).

Patent Foramen Ovale and Other Cardiopathies as Causes of Embolic Stroke With Unknown Source

In patients with stroke caused by cardiac embolism, the responsible heart diseases include atrial fibrillation, acute myocardial infarction, sick sinus syndrome, valvular disease, and significant heart failure. When there is no clear source of the embolism, the condition is referred to as "embolic stroke with unknown source (ESUS)." Recent studies have shown that the most common cause of ESUS is a right-to-left cardiac shunt through a patent foramen ovale (PFO). However, considering that PFOs are found in up to 25% of the general population, their presence does not necessarily indicate causality. In patients with ESUS associated with a PFO, either anticoagulants or antiplatelets are used for the prevention of future strokes or transient ischemic attacks. However, it currently remains unclear which treatment is superior. Nevertheless, recent randomized clinical trials have shown that percutaneous closure of the PFO more effectively reduces the incidence of recurrent strokes compared to medical therapy alone in patients with PFO-related strokes. This benefit is especially significant when the PFO carries high-risk features, such as a large shunt or the presence of an atrial septal aneurysm. Furthermore, the effectiveness of PFO closure has been well documented in young patients (<60 years) with a high-risk PFO development. In other cases, the therapeutic decision should be made through discussion among neurologists, cardiologists, and patients. Notably, in ESUS patients without a PFO, the underlying heart condition itself may be the source of embolism, with left atrial enlargement being the most important factor. Theoretically, anticoagulants such as non-vitamin K antagonist oral anticoagulants (NOACs) would be an effective therapy in these cases. However, recent trials have failed to show that NOACs are superior to antiplatelets in preventing further strokes in these patients. This may be due to the still uncertain definition of emboligenic cardiopathy and the presence of other potential embolic sources, such as mild but emboligenic arterial diseases. Overall, further research is needed to elucidate the source of embolism and to determine an effective management strategy for patients with ESUS.

Neurologists Preferences on Basic and Advanced Cardiac Imaging Utilization in Ischemic Stroke Patients

INTRODUCTION

It is unknown how cardiac imaging studies are used by neurologists to investigate cardioembolic sources in ischemic stroke patients.

METHODS

Between August 12, 2023, and December 8, 2023, we conducted an international survey among neurologists from Europe, North America, South America, and Asia, to investigate the frequency of utilization of cardiac imaging studies for the detection of cardioembolic sources of ischemic stroke. Questions were structured into deciles of percentage utilization of transthoracic echocardiography (TTE), transesophageal echocardiography (TEE), ECG-gated cardiac computed tomography (G-CCT), and cardiac magnetic resonance imaging (CMRI). We estimated the weighted proportion (x¯) of utilization of each cardiac imaging modality, both globally and by continent. We also investigated the use of head and neck computed tomography angiography (CTA) as an emerging approach to the screening of cardioembolic sources.

RESULTS

A total of 402 neurologists from 64 countries completed the survey. Globally, TTE was the most frequently used cardiac imaging technology (x¯ = 71.2%), followed by TEE (x¯ = 15.8%), G-CCT (x¯ = 10.9%), and CMRI (x¯ = 7.7%). Findings were consistent across all continents. A total of 288 respondents routinely used a CTA in the acute ischemic stroke phase (71.6%), but the CTA included a non-gated CCT in only 15 cases (5.2%).

CONCLUSIONS

This survey suggests that basic cardiac imaging is not done in all ischemic stroke patients evaluated in 4 continents. We also found a substantially low utilization of advanced cardiac imaging studies. Easier to adopt screening methods for cardioembolic sources of embolism are needed.

Ischemic Stroke and Reduced Left Ventricular Ejection Fraction: A Multidisciplinary Approach to Optimize Brain and Cardiac Health

Reduced left ventricular ejection fraction ≤40%, a known risk factor for adverse cardiac outcomes and recurrent acute ischemic stroke, may be detected during an acute ischemic stroke hospitalization. A multidisciplinary care paradigm informed by neurology and cardiology expertise may facilitate the timely implementation of an array of proven heart failure-specific therapies and procedures in a nuanced manner to optimize brain and cardiac health.

Now You See It, Now You Don't: Point-of-Care Ultrasound Identification of Left Ventricular Thrombus-in-Transit

BACKGROUND

Left-sided intracardiac thrombi are most commonly seen in conditions with decreased cardiac flow, such as myocardial infarction or atrial fibrillation. They can be propagated into the systemic circulation, leading to a cerebrovascular accident. Identification of thrombus-in-transit via point-of-care ultrasound (POCUS) has the potential to change patient management given its association with high patient morbidity and mortality.

CASE REPORT

An intubated 60-year-old man was transferred to our emergency department for management of altered mental status and seizure-like activity. The patient was markedly hypotensive on arrival, and cardiac POCUS was performed to identify potential causes of hypotension. A left ventricular thrombus-in-transit was identified. The thrombus was notably absent on a repeat POCUS examination < 10 min later, which led to concern for thrombus propagation. Furthermore, the patient's vasopressor requirements had significantly increased in that time period. Subsequent emergent neuroimaging revealed a large ischemic stroke in the left internal carotid and middle cerebral artery distribution. The patient was, unfortunately, deemed to not be a candidate for either thrombectomy or thrombolysis and ultimately expired in the hospital. Why Should an Emergency Physician Be Aware of This? Serial POCUS examinations identified the propagation of this patient's thrombus-in-transit, leading the physician to change the initial presumptive diagnosis and treatment course, and pursue further imaging and workup for ischemic stroke. Identification of a thrombus-in-transit is a clue to potentially underlying critical pathology and should be followed with serial POCUS examinations to assess for treatment efficacy and thrombus propagation.

Prophylactic Anticoagulation to Prevent Left Ventricular Thrombus Following Acute Myocardial Infarction: A Systematic Review and Meta-Analysis

Clinical practice guidelines from the American Heart Association recommend consideration of prophylactic anticoagulation to prevent left ventricular thrombus (LVT) formation in patients with anterior ST-elevation myocardial infarction. These guidelines were given a low certainty of evidence (class IIb, level C), relying primarily on case studies and expert consensus to inform practice. Our objective was to compare the safety and efficacy of prophylactic anticoagulation, in addition to dual antiplatelet therapy, in the current era of timely primary percutaneous coronary intervention. Electronic databases, including EMBASE, MEDLINE, and Cochrane Library, were systematically searched from January 2012 through June 2022. A total of 7,378 publications were screened, and 5 publications were eventually included in this review: 1 randomized control trial and 4 retrospective studies involving 1,461 patients. Data were pooled using a fixed-effects model and reported as odds ratios (ORs) with 95% confidence intervals (CIs). The primary outcome of interest was the rate of LVT formation, and the secondary outcomes were the rate of major bleeding and systemic embolism. Pooled analysis showed a significantly lower rate of LVT formation (OR 0.28, 95% CI 0.11 to 0.73, p <0.01) and significantly higher rates of bleeding (OR 2.85, 95% CI 1.13 to 7.24, p = 0.03) in the triple therapy group compared with dual antiplatelet therapy. No significant difference was observed in the rate of systemic embolism between the groups (OR 0.37, 95% CI 0.12 to 1.13, p = 0.08). In this meta-analysis, there is no conclusive evidence to either support or oppose the use of triple therapy for LVT prevention in patients with anterior ST-elevation myocardial infarction treated with primary percutaneous coronary intervention. Appropriately powered randomized controlled trials are warranted to further evaluate the benefits of LVT prevention against the risks of major bleeding in this population.

MRI in the Evaluation of Cryptogenic Stroke and Embolic Stroke of Undetermined Source

Cryptogenic stroke refers to a stroke of undetermined etiology. It accounts for approximately one-fifth of ischemic strokes and has a higher prevalence in younger patients. Embolic stroke of undetermined source (ESUS) refers to a subgroup of patients with nonlacunar cryptogenic strokes in whom embolism is the suspected stroke mechanism. Under the classifications of cryptogenic stroke or ESUS, there is wide heterogeneity in possible stroke mechanisms. In the absence of a confirmed stroke etiology, there is no established treatment for secondary prevention of stroke in patients experiencing cryptogenic stroke or ESUS, despite several clinical trials, leaving physicians with a clinical dilemma. Both conventional and advanced MRI techniques are available in clinical practice to identify differentiating features and stroke patterns and to determine or infer the underlying etiologic cause, such as atherosclerotic plaques and cardiogenic or paradoxical embolism due to occult pelvic venous thrombi. The aim of this review is to highlight the diagnostic utility of various MRI techniques in patients with cryptogenic stroke or ESUS. Future trends in technological advancement for promoting the adoption of MRI in such a special clinical application are also discussed.

Magnetic resonance imaging for diagnostic workup of embolic stroke of undetermined source: A systematic review

BACKGROUND

Embolic stroke of undetermined source (ESUS) refers to ischemic stroke where the underlying cause of thromboembolism cannot be found despite the recommended diagnostic workup. Unidentified source of emboli hinders clinical decision-making and patient management with detrimental consequences on long-term prognosis. The rapid development and versatility of magnetic resonance imaging (MRI) make it an appealing addition to the diagnostic routine of patients with ESUS for the assessment of potential vascular and cardiac embolic sources.

AIMS

To review the use of MRI in the identification of cardiac and vascular embolic sources in ESUS and to assess the reclassification value of MRI examinations added to the conventional workup of ESUS.

SUMMARY OF REVIEW

We reviewed the use of cardiac and vascular MRI for the identification of a variety of embolic sources associated with ESUS, including atrial cardiomyopathy, left ventricular pathologies, and supracervical atherosclerosis in carotid and intracranial arteries and in distal thoracic aorta. The additional reclassification after MRI examinations added to the workup of patients with ESUS ranged from 6.1% to 82.3% and varied depending on the combination of imaging modalities.

CONCLUSION

MRI techniques allow us to identify additional cardiac and vascular embolic sources and may further decrease the prevalence of patients with the diagnosis of ESUS.

High Prevalence of New Clinically Significant Findings in Patients With Embolic Stroke of Unknown Source Evaluated by Cardiac Magnetic Resonance Imaging

BACKGROUND

Embolic stroke of unknown source (ESUS) accounts for 1 in 6 ischemic strokes. Current guidelines do not recommend routine cardiac magnetic resonance (CMR) imaging in ESUS, and beyond the identification of cardioembolic sources, there are no data assessing new clinical findings from CMR in ESUS. This study aimed to assess the prevalence of new cardiac and noncardiac findings and to determine their impact on clinical care in patients with ESUS.

METHODS AND RESULTS

In this prospective, multicenter, observational study, CMR imaging was performed within 3 months of ESUS. All scans were reported according to standard clinical practice. A new clinical finding was defined as one not previously identified through prior clinical evaluation. A clinically significant finding was defined as one resulting in further investigation, follow-up, or treatment. A change in patient care was defined as initiation of medical, interventional, surgical, or palliative care. From 102 patients recruited, 96 underwent CMR imaging. One or more new clinical findings were observed in 59 patients (61%). New findings were clinically significant in 48 (81%) of these patients. Of 40 patients with a new clinically significant cardiac finding, 21 (53%) experienced a change in care (medical therapy, n=15; interventional/surgical procedure, n=6). In 12 patients with a new clinically significant extracardiac finding, 6 (50%) experienced a change in care (medical therapy, n=4; palliative care, n=2).

CONCLUSIONS

CMR imaging identifies new clinically significant cardiac and noncardiac findings in half of patients with recent ESUS. Advanced cardiovascular screening should be considered in patients with ESUS.

REGISTRATION

URL: https://www.clinicaltrials.gov; Unique identifier: NCT04555538.

Role of cardiac computed tomography in hyperacute stroke assessment

BACKGROUND

Incorporating cardiac CT with hyperacute stroke imaging may increase the yield for cardioembolic sources. It is not clarified whether stroke severity influences on rates of intracardiac thrombus. We aimed to investigate a National Institutes of Health Stroke Scale (NIHSS) threshold below which acute cardiac CT was unnecessary.

METHODS

Consecutive patients with suspected stroke who underwent multimodal brain imaging and concurrent non-gated cardiac CT with delayed timing were prospectively recruited from 1st December 2020 to 30th November 2021. We performed receiver operating characteristics analysis of the NIHSS and intracardiac thrombus on hyperacute cardiac CT.

RESULTS

A total of 314 patients were assessed (median age 69 years, 61% male). Final diagnoses were ischemic stroke (n=205; 132 etiology-confirmed stroke, independent of cardiac CT and 73 cryptogenic), transient ischemic attack (TIA) (n=21) and stroke-mimic syndromes (n=88). The total yield of cardiac CT was 8 intracardiac thrombus and 1 dissection. Cardiac CT identified an intracardiac thrombus in 6 (4.5%) with etiology-confirmed stroke, 2 (2.7%) with cryptogenic stroke, and none in patients with TIA or stroke-mimic. All of those with intracardiac thrombus had NIHSS ≥4 and this was the threshold below which hyperacute cardiac CT was not justified (sensitivity 100%, specificity 38%, positive predictive value 4.0%, negative predictive value 100%).

CONCLUSIONS

A cutoff NIHSS ≥4 may be useful to stratify patients for cardiac CT in the hyperacute stroke setting to optimize its diagnostic yield and reduce additional radiation exposure.

P-wave indices and left atrial mechanics as predictors of atrial cardiopathy in embolic stroke of undetermined source

Recent research has shed light on the culpability of LA (left atrial) abnormality, in the form of atrial cardiopathy, as an independent risk factor for the development of atrial fibrillation, LA thrombus and subsequent stroke. The aim of this study was to measure LA electromechanical dissociation (EMD), LA volumes, P-wave dispersion (PWD) and P-wave terminal force in V1 (PTFV1) as markers of atrial cardiopathy in patients with ESUS (embolic stroke of undetermined source), to determine whether atrial cardiopathy is an integral part in the causal pathway of ESUS. 28 patients presenting with ischemic stroke and fulfilling the criteria for ESUS were enrolled into this cross-sectional, observational study along with a control group of 28 age- and gender-matched apparently healthy individuals. On ECG, PWD and PTFV1 were measured. On echocardiography, LA EMD and LA volumes were recorded. Increased PWD (34.14 ± 9.89 ms vs. 27.32 ± 8.95 ms; p = 0.01), atrial EMD (73.32 ± 16.31 ms vs. 63.63 ± 13.59 ms; p = 0.02) and LA volumes were observed in patients with ESUS as compared to controls. A significant correlation was also found between these parameters (p < 0.01). According to the results of our study, PWD, atrial EMD and LA volumes may be novel predictors for ESUS. Our results support the notion that atrial cardiopathy is a distinct mechanism of thrombosis in ESUS patients. Further research is required to clarify its function in the causation of stroke, ESUS in particular.

Coeliac axis thrombosis and acute hepatic failure in a patient with dilated cardiomyopathy

We present the case of a female patient in her 40s who presented with jaundice, orthopnoea, paroxysmal nocturnal dyspnoea and bilateral pedal oedema. After extensive investigations, she was diagnosed with hepatic dysfunction, dilated cardiomyopathy (DCM) and coeliac axis thrombosis. Her case was further complicated with episodes of torsades de pointes due to metabolic disturbance, with consequent sudden cardiac arrest. In this case report, we explore the clinical features, pathophysiology and treatment of acute hepatic failure and coeliac axis thrombosis, secondary to DCM and alcoholic liver disease.

What's the optimal duration of anticoagulation in patients with left ventricular thrombus?

INTRODUCTION

Left ventricular thrombus (LVT) occurs in acute myocardial infarction and in ischemic and non-ischemic cardiomyopathies. LVT may result in embolic stroke. Currently, the duration of anticoagulation for LVT is unclear. This is an important clinical question as prolonged anticoagulation is associated with increased bleeding risks, while premature discontinuation may result in embolic complications.

AREAS COVERED

There are no randomized trial data regarding anticoagulation duration for LVT. Guidelines and expert consensus recommend anticoagulation for 3-6 months with cessation of anticoagulation if interval imaging demonstrates thrombus resolution. Cardiac magnetic resonance imaging (CMR) is more sensitive and specific compared to echocardiography for LVT detection, and may be appropriate for high-risk patients. Prolonged anticoagulation may be considered in unresolved protuberant or mobile LVT, and in patients with resolved LVT but persistent depressed left ventricular ejection fraction and/or myocardial akinesia or dyskinesia.

EXPERT OPINION

CMR will likely be increasingly used for LVT surveillance to guide anticoagulation duration. Further research is needed to determine which patients with persistent LVT on CMR benefit from prolonged anticoagulation.

Diagnosis and Management of Cardioembolic Stroke

OBJECTIVE

Cardioembolic stroke accounts for nearly 30% of ischemic strokes. Prompt diagnosis of the underlying mechanism may improve secondary prevention strategies. This article reviews recent randomized trials, observational studies, case reports, and guidelines on the diagnosis and treatment of cardioembolic stroke.

LATEST DEVELOPMENTS

Several pathologies can lead to cardioembolic stroke, including atrial fibrillation, aortic arch atheroma, patent foramen ovale, left ventricular dysfunction, and many others. Secondary stroke prevention strategies differ across these heterogeneous mechanisms. In addition to medical treatment advances such as the use of direct oral anticoagulants in patients with atrial fibrillation, surgical treatments such as closure of patent foramen ovale have been shown to reduce the risk of recurrent stroke in select patients. Furthermore, left atrial appendage occlusion is a promising strategy for patients with atrial fibrillation who are candidates for short-term oral anticoagulation therapy but not long-term oral anticoagulation therapy.

ESSENTIAL POINTS

A thorough diagnostic evaluation is essential to determine cardioembolic causes of stroke. In addition to risk factor management and lifestyle modifications, identification and targeting of the underlying cardioembolic stroke mechanisms will lead to improved stroke prevention strategies in patients with cardioembolic stroke.

A Bibliometric Analysis of Cardioembolic Stroke From 2012 to 2022

Cardioembolic stroke, a subtype of ischemic stroke with the worst prognosis, is quietly threatening public health. We aimed to visualize the development trend and hotspots of research on cardioembolic stroke. A total of 2886 papers about cardioembolic stroke published from 2012 to 2022 were retrieved in the Web of Science Core Collection (WoSCC) database. Further, we performed a bibliometric analysis of these publications, such as generating cooperation maps, co-citation analysis of journals and references, and cluster analysis of keywords. According to the results, cardioembolic stroke research faces many clinical challenges. We obtained the knowledge maps of countries/institutions, authors, journals with high publications and citations, and representative references in this field. Studies about optimal prevention strategies for cardioembolic stroke, identification of cardioembolism in cryptogenic stroke, and prophylactic anticoagulation for patients with embolic stroke of undetermined source (ESUS) or at high risk of left ventricle (LV) thrombus are in the spotlight.

Management of Patients at Risk for and With Left Ventricular Thrombus: A Scientific Statement From the American Heart Association

Despite the many advances in cardiovascular medicine, decisions concerning the diagnosis, prevention, and treatment of left ventricular (LV) thrombus often remain challenging. There are only limited organizational guideline recommendations with regard to LV thrombus. Furthermore, management issues in current practice are increasingly complex, including concerns about adding oral anticoagulant therapy to dual antiplatelet therapy, the availability of direct oral anticoagulants as a potential alternative option to traditional vitamin K antagonists, and the use of diagnostic modalities such as cardiac magnetic resonance imaging, which has greater sensitivity for LV thrombus detection than echocardiography. Therefore, this American Heart Association scientific statement was commissioned with the goals of addressing 8 key clinical management questions related to LV thrombus, including the prevention and treatment after myocardial infarction, prevention and treatment in dilated cardiomyopathy, management of mural (laminated) thrombus, imaging of LV thrombus, direct oral anticoagulants as an alternative to warfarin, treatments other than oral anticoagulants for LV thrombus (eg, dual antiplatelet therapy, fibrinolysis, surgical excision), and the approach to persistent LV thrombus despite anticoagulation therapy. Practical management suggestions in the form of text, tables, and flow diagrams based on careful and critical review of actual study data as formulated by this multidisciplinary writing committee are given.

Review and update of the concept of embolic stroke of undetermined source

Ischaemic strokes have traditionally been classified according to the TOAST criteria, in which strokes with unclear aetiology are classified as cryptogenic strokes. However, the definition of cryptogenic stroke did not meet the operational criteria necessary to define patient populations for randomized treatment trials. To address this problem, the concept of embolic stroke of undetermined source (ESUS) was developed and published in 2014. A hypothesis that underpinned this concept was that most strokes in patients with ESUS are caused by embolic events, perhaps many cardioembolic, and that anticoagulation would prevent secondary ischaemic events. On this basis, two large randomized trials were conducted to compare the non-vitamin K antagonist oral anticoagulants (NOACs) dabigatran and rivaroxaban with aspirin. Neither NOAC was superior to aspirin in these trials, although subgroups of patients with ESUS seemed to benefit specifically from anticoagulation or antiplatelet therapy. The neutral results of the trials of anticoagulation and insights into ESUS from research conducted since the concept was introduced warrant reassessment of the ESUS construct as a research concept and a treatment target. In this Review, we discuss the evidence produced since the concept of ESUS was introduced, and propose updates to the criteria and diagnostic algorithm in light of the latest knowledge.

Advances in Recurrent Stroke Prevention: Focus on Antithrombotic Therapies

The past decade has seen significant advances in stroke prevention. These advances include new antithrombotic agents, new options for dyslipidemia treatment, and novel techniques for surgical stroke prevention. In addition, there is greater recognition of the benefits of multifaceted interventions, including the role of physical activity and dietary modification. Despite these advances, the aging of the population and the high prevalence of key vascular risk factors pose challenges to reducing the burden of stroke. Using a cause-based framework, current approaches to prevention of cardioembolic, cryptogenic, atherosclerotic, and small vessel disease stroke are outlined in this paper. Special emphasis is given to recent trials of antithrombotic agents, including studies that have tested combination treatments and responses according to genetic factors.

Recent Progress on Micro-Fabricated Alkali Metal Vapor Cells

Alkali vapor cells are the core components of atomic sensing instruments such as atomic gyroscopes, atomic magnetometers, atomic clocks, etc. Emerging integrated atomic sensing devices require high-performance miniaturized alkali vapor cells, especially micro-fabricated vapor cells. In this review, bonding methods for vapor cells of this kind are summarized in detail, including anodic bonding, sacrificial micro-channel bonding, and metal thermocompression bonding. Compared with traditional through-lighting schemes, researchers have developed novel methods for micro-fabricated vapor cells under both single- and double-beam schemes. In addition, emerging packaging methods for alkali metals in micro-fabricated vapor cells can be categorized as physical or chemical approaches. Physical methods include liquid transfer and wax pack filling. Chemical methods include the reaction of barium azide with rubidium chloride, ultraviolet light decomposition (of rubidium azide), and the high-temperature electrolysis of rubidium-rich glass. Finally, the application trend of micro-fabricated alkali vapor cells in the field of micro-scale gyroscopes, micro-scale atomic clocks, and especially micro-scale biomagnetometers is reviewed. Currently, the sensing industry has become a major driving force for the miniaturization of atomic sensing devices, and in the near future, the micro-fabricated alkali vapor cell technology of atomic sensing devices may experience extensive developments.

Imaging of left heart intracardiac thrombus: clinical needs, current imaging, and emerging cardiac magnetic resonance techniques

Intracardiac thrombus in the left atrium and atrial appendage (LA/LAA) and left ventricle (LV) increases the risk of systemic thromboembolism and causes potentially devastating diseases such as ischemic stroke and acute ischemia in abdominal organs and lower extremities. Detecting the presence and monitoring the resolution of left heart intracardiac thrombus are of vital importance for stratifying patients and guiding treatment decisions. Currently, echocardiography is the most frequently used method for the above clinical needs, followed by computed tomography. An increasing number of studies have been performed to investigate the value of cardiac magnetic resonance (CMR) as an alternative imaging modality given its several unique strengths. This article provides an overview of the clinical relevance of the LA/LAA and LV thrombus as well as the diagnostic performance of the current imaging modalities and emerging CMR techniques.

OUP accepted manuscript

The management of patients with stroke is often multidisciplinary, involving various specialties and healthcare professionals. Given the common shared risk factors for stroke and cardiovascular disease, input may also be required from the cardiovascular teams, as well as patient caregivers and next-of-kin. Ultimately, the patient is central to all this, requiring a coordinated and uniform approach to the priorities of post-stroke management, which can be consistently implemented by different multidisciplinary healthcare professionals, as part of the patient ‘journey’ or ‘patient pathway,’ supported by appropriate education and tele-medicine approaches. All these aspects would ultimately aid delivery of care and improve patient (and caregiver) engagement and empowerment. Given the need to address the multidisciplinary approach to holistic or integrated care of patients with heart disease and stroke, the European Society of Cardiology Council on Stroke convened a Task Force, with the remit to propose a consensus on Integrated care management for optimizing the management of stroke and associated heart disease. The present position paper summarizes the available evidence and proposes consensus statements that may help to define evidence gaps and simple practical approaches to assist in everyday clinical practice. A post-stroke ABC pathway is proposed, as a more holistic approach to integrated stroke care, would include three pillars of management:

A: Appropriate Antithrombotic therapy.

B: Better functional and psychological status.

C: Cardiovascular risk factors and Comorbidity optimization (including lifestyle changes).

Features of Cerebral Infarction Due to Left Ventricular Thrombus

Objective Left ventricular (LV) thrombus is a rare condition in acute cerebral infarction. The prevalence and features of cerebral infarction with LV thrombus are unclear. We explored the features of cerebral infarction due to LV thrombus. Methods In this single-center retrospective study, we investigated consecutive patients with acute ischemic stroke admitted within seven days of the onset who had LV thrombus found by transthoracic echocardiography (TTE). First, we calculated the prevalence of LV thrombus in patients with cardioembolic stroke (CES). Second, we investigated the baseline characteristics, including the TTE findings and features of cerebral infarction due to LV thrombus. Results From June 2012 to January 2019, a total of 5,693 patients were enrolled. Of these, 1,408 (25%) patients were diagnosed with CES. Of these 1,408 patients with CES, 13 (0.9%) had LV thrombus indicated by TTE, with dilative cardiomyopathy, subacute myocardial infarction, and old myocardial infarction present in 1 (8%), 2 (15%), and 10 (77%), respectively. The ejection fraction (EF) was 48.9% (25.3-64.7%). The maximum longitudinal size of LV thrombus was 13.4 (0.97-38.1) mm, and there was no correlation between the size of the LV thrombus and the EF. Regarding the features of cerebrovascular infarction, major vessel occlusion was observed in 10 (77%) patients. Six (46%) patients were found to have good outcomes (modified Rankin Scale 0-2) at 90 days after the onset. Conclusion LV thrombus was seen in 0.9% of patients with CES. Many of the patients with LV thrombus had major vessel occlusion.

Embolic Stroke of Undetermined Source: Approaches in Risk Stratification for Cardioembolism

Ischemic stroke is a leading cause of morbidity and mortality worldwide. Embolic stroke of undetermined source has been recently proposed to categorize nonlacunar ischemic strokes without confirmed etiology after adequate investigation with a likely embolic stroke mechanism. A strategy of empirical anticoagulation for embolic stroke of undetermined source patients is attractive but may only be beneficial in a select subset of patients. Strategies which would help identify the subset of embolic stroke of undetermined source patients most likely to have cardioembolic origin of stroke, and hence benefit from anticoagulation, are needed. This article will review current evidence which may be useful in the development of a risk stratification approach based on arrhythmia monitoring, cardiac imaging, and clinical risk stratification. This approach may be beneficial in clinical practice in improving patient outcomes and reducing stroke recurrence in this population; however, further work is required with active trials underway.

Left Ventricular Dysfunction Among Patients With Embolic Stroke of Undetermined Source and the Effect of Rivaroxaban vs Aspirin: A Subgroup Analysis of the NAVIGATE ESUS Randomized Clinical Trial

Importance

It is uncertain whether anticoagulation is superior to aspirin at reducing recurrent stroke in patients with recent embolic strokes of undetermined source (ESUS) and left ventricular (LV) dysfunction.

Objective

To determine whether anticoagulation is superior to aspirin in reducing recurrent stroke in patients with ESUS and LV dysfunction.

Design, Setting, and Participants

Post hoc exploratory analysis of data from the New Approach Rivaroxaban Inhibition of Factor Xa in a Global Trial vs Aspirin to Prevent Embolism in ESUS (NAVIGATE ESUS) trial, a randomized, phase 3 clinical trial with enrollment from December 2014 to September 2017. The study setting included 459 stroke recruitment centers in 31 countries. Patients 50 years or older who had neuroimaging-confirmed ESUS between 7 days and 6 months before screening were eligible. Of the 7213 NAVIGATE ESUS participants, 7107 (98.5%) had a documented assessment of LV function at study entry and were included in the present analysis. Data were analyzed in January 2021.

Interventions

Participants were randomized to receive either 15 mg of rivaroxaban or 100 mg of aspirin once daily.

Main Outcomes and Measures

The study examined whether rivaroxaban was superior to aspirin at reducing the risk of (1) the trial primary outcome of recurrent stroke or systemic embolism and (2) the trial secondary outcome of recurrent stroke, systemic embolism, myocardial infarction, or cardiovascular mortality during a median follow-up of 10.4 months. LV dysfunction was identified locally through echocardiography and defined as moderate to severe global impairment in LV contractility and/or a regional wall motion abnormality. A Cox proportional hazards model was used to assess for treatment interaction and to estimate the hazard ratios for those randomized to rivaroxaban vs aspirin by LV dysfunction status.

Results

LV dysfunction was present in 502 participants (7.1%). Of participants with LV dysfunction, the mean (SD) age was 67 (10) years, and 130 (26%) were women. Among participants with LV dysfunction, annualized primary event rates were 2.4% (95% CI, 1.1-5.4) in those assigned to rivaroxaban vs 6.5% (95% CI, 4.0-11.0) in those assigned aspirin. Among the 6605 participants without LV dysfunction, rates were similar between those assigned to rivaroxaban (5.3%; 95% CI, 4.5-6.2) vs aspirin (4.5%; 95% CI, 3.8-5.3). Participants with LV dysfunction assigned to rivaroxaban vs aspirin had a lower risk of the primary outcome (hazard ratio, 0.36; 95% CI, 0.14-0.93), unlike those without LV dysfunction (hazard ratio, 1.16; 95% CI, 0.93-1.46) (P for treatment interaction = .03). Results were similar for the secondary outcome.

Conclusions and Relevance

In this post hoc exploratory analysis, rivaroxaban was superior to aspirin in reducing the risk of recurrent stroke or systemic embolism among NAVIGATE ESUS participants with LV dysfunction.

Trial Registration

ClinicalTrials.gov Identifier: NCT02313909.

EACVI recommendations on cardiovascular imaging for the detection of embolic sources: endorsed by the Canadian Society of Echocardiography

Cardioaortic embolism to the brain accounts for approximately 15-30% of ischaemic strokes and is often referred to as 'cardioembolic stroke'. One-quarter of patients have more than one cardiac source of embolism and 15% have significant cerebrovascular atherosclerosis. After a careful work-up, up to 30% of ischaemic strokes remain 'cryptogenic', recently redefined as 'embolic strokes of undetermined source'. The diagnosis of cardioembolic stroke remains difficult because a potential cardiac source of embolism does not establish the stroke mechanism. The role of cardiac imaging-transthoracic echocardiography (TTE), transoesophageal echocardiography (TOE), cardiac computed tomography (CT), and magnetic resonance imaging (MRI)-in the diagnosis of potential cardiac sources of embolism, and for therapeutic guidance, is reviewed in these recommendations. Contrast TTE/TOE is highly accurate for detecting left atrial appendage thrombosis in patients with atrial fibrillation, valvular and prosthesis vegetations and thrombosis, aortic arch atheroma, patent foramen ovale, atrial septal defect, and intracardiac tumours. Both CT and MRI are highly accurate for detecting cavity thrombosis, intracardiac tumours, and valvular prosthesis thrombosis. Thus, CT and cardiac magnetic resonance should be considered in addition to TTE and TOE in the detection of a cardiac source of embolism. We propose a diagnostic algorithm where vascular imaging and contrast TTE/TOE are considered the first-line tool in the search for a cardiac source of embolism. CT and MRI are considered as alternative and complementary tools, and their indications are described on a case-by-case approach.

Cardiovascular MRI Compared to Echocardiography to Identify Cardioaortic Sources of Ischemic Stroke: A Systematic Review and Meta-Analysis

Background: To compare the diagnostic yield of echocardiography and cardiovascular MRI (CMR) to detect structural sources of embolism, in patients with ischemic stroke with a secondary analysis of non-stroke populations.

Methods and Results: We searched MEDLINE/Embase (from 01.01.2000 to 24.04.2021) for studies including CMR to assess prespecified sources of embolism. Comparison included transthoracic and/or transesophageal echocardiography. Two authors independently screened studies, extracted data and assessed bias using the QUADAS-2 tool. Estimates of diagnostic yield were reported and pooled. Twenty-seven studies with 2,525 patients were included in a study-level analysis. Most studies had moderate to high risk of bias. Persistent foramen ovale, complex aortic plaques, left ventricular and left atrial thrombus were the most common pathologies. There was no difference in the yield of left ventricular thrombus detection between both modalities for stroke populations (4 studies), but an increased yield of CMR in non-stroke populations (28.1 vs. 16.0%, P < 0.001, 10 studies). The diagnostic yield in stroke patients for detection of persistent foramen ovale was lower in CMR compared to transoesophageal echocardiography (29.3 vs. 53.7%, P < 0.001, 5 studies). For both echocardiography and CMR the clinical impact of the management consequences derived from many of the diagnostic findings remained undetermined in the identified studies.

Conclusions: Echocardiography and CMR seem to have similar diagnostic yield for most cardioaortic sources of embolism except persistent foramen ovale and left ventricular thrombus. Randomized controlled diagnostic trials are necessary to understand the impact on the management and potential clinical benefits of the assessment of structural cardioaortic stroke sources.

Registration: PROSPERO: CRD42020158787.

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.

Left atrial dimension and ischemic stroke in patients with and without atrial fibrillation

The incidence of ischemic stroke (IS) increases in patients with enlarged left atrium (LA) irrespective of whether or not the existence of atrial fibrillation (AF). In such situation, it is unclear whether the impact of LA on incidence of IS still significant in young, non-AF patients with enlarged LA who are primarily unconcerned on anticoagulation therapy. The study population consisted of 18,511 consecutive patients not receiving oral anticoagulants and undergoing echocardiography with measurement of LAD at baseline. The incidence rate of ischemic stroke was calculated in 3 groups according to left atrial dimension (LAD; < 30, 30-45 and ≥ 45 mm) in AF and non-AF patients. Further subgroup analysis was performed in stratification by elderly and young (aged ≥ 65 and < 65 years, respectively). The incidences of IS (per 100 patient-years) were 0.11 and 0.71 in non-AF and AF patients with LAD < 30 mm, respectively, which increased to 0.58 and 1.35 in LAD ≥ 45 mm (adjusted hazard ratios [HRs]; 1.95 [95% confidence intervals, CIs: 0.76-5.01] and 1.22 [95% CIs: 0.27-5.58], interaction P was 0.246). In non-AF patients, the incidences of IS were 0.30 and 0.04 in elderly and young patients with LAD < 30 mm, which increased to 0.67 and 0.48 in LAD ≥ 45 mm (adjusted HRs; 1.34 [95% CIs: 0.43-4.15] and 4.21 [95% CIs: 0.77-23.12], interaction P was 0.158). The incidence of IS significantly increased with increase of LAD in non-AF, especially in non-AF and young patients, although the difference was not independent of other clinical factors. The impact of LAD on IS was numerically larger in non-AF than in AF, and larger in young and non-AF than in elderly counterpart, although a significant interaction was not observed in this small population. Further studies with large population are necessary to judge whether these population with enlarged LA need antithrombotic therapy.

Blind Exchange With Mini-Pinning Technique Using the Tron Stent Retriever for Middle Cerebral Artery M2 Occlusion Thrombectomy in Acute Ischemic Stroke

Introduction: The usefulness of the blind exchange with mini-pinning (BEMP) technique has recently been reported for mechanical thrombectomy in patients with stroke owing to medium vessel occlusion (MeVO). The Tron stent retriever can be delivered and deployed through a 0.0165-inch microcatheter. This retriever has potential as an effective and safe treatment for acute ischemic stroke (AIS) due to occlusion of the M2 segment of the middle cerebral artery (MCA). Here, we report the outcomes of the BEMP technique using Tron stent retrievers for M2 occlusion thrombectomy.

Methods: Consecutive patients with AIS owing to M2 occlusion who underwent the BEMP technique using 2 × 15-mm or 4 × 20-mm Tron stent retrievers were included. The technique involves deploying a Tron stent retriever through a 0.0165-inch microcatheter, followed by microcatheter removal and blind navigation of a 3MAX or 4MAX aspiration catheter over the bare Tron delivery wire until the aspiration catheter reaches the clot. A Tron stent retriever is inserted into the aspiration catheter like a cork and subsequently pulled as a unit. We assessed procedural outcomes [first-pass expanded thrombolysis in cerebral infarction (eTICI) score 2c/3 and 2b/2c/3], safety outcomes [symptomatic intracranial hemorrhage (sICH)], and clinical outcomes (good outcome rate defined as modified Rankin Scale score 0–2 at 90 days and mortality at 90 days).

Results: Eighteen M2 vessels were treated in 15 patients (six female, median age: 80 years, and median National Institutes of Health Stroke Scale score: 18). The BEMP technique was performed successfully in all cases. Whether to use a 3MAX or 4MAX catheter was determined by considering one of the following target vessels: dominant, non-dominant, or co-dominant M2 (3MAX, n = 9; 4MAX, n = 9). The first-pass eTICI 2c/3 and 2b/2c/3 rates were 47 (7/15) and 60% (9/15), respectively; sICH was not observed. Seven patients (47%) achieved good outcomes, and one patient (7%) died within 90 days.

Conclusions: The Tron stent retriever was safely and effectively used in the BEMP technique for acute MCA M2 occlusion and can be combined with a 0.0165-inch microcatheter, which may be useful for treating MeVO, in general.

Partitioning risk factors for embolic stroke of undetermined source using exploratory factor analysis

Background

Embolic stroke of undetermined source (ESUS) accounts for up to 25% of strokes. Understanding risk factors associated with ESUS is important in reducing stroke burden worldwide. However, ESUS patients are younger and present with fewer traditional risk factors. Significant global variation in ESUS populations also exists making the clinical picture of this type of stroke unclear.

Methods and results

ESUS patients were pair matched for age, sex, and ethnicity with a group of all other strokes (both n = 331). Exploratory factor analysis was applied in both groups to 14 risk and clinical factors to identify latent factors. In ESUS patients, two latent factors emerged consisting primarily of heart-related variables such as left ventricular wall motion abnormalities, reduced ejection fraction, and increased left atrial volume index, as well as aortic arch atherosclerosis. This is in comparison to the all other strokes group, which was dominated by traditional stroke risk factors.

Conclusions

Our findings support the existence of a unique pattern of risk factors specific to ESUS. We show that LVWMA and corresponding changes in left heart function are a potential source of emboli in these patients. In addition, the clustering of aortic arch atherosclerosis with left heart factors suggests a causal link. Through the application of exploratory factor analysis, this work contributes to a further understanding of stroke mechanisms in ESUS.

[Embolic stroke of undetermined source (ESUS) - Classification of a new stroke entity]

Embolic stroke of undetermined source (ESUS) represents a subpopulation of cryptogenic strokes defined by its embolic stroke pattern on imaging and if after a carefully performed diagnostic evaluation, a specific, well recognized cause of stroke has not been identified. This review article analyses the basics of the ESUS concept and provides an overview of the evidence from recent cohort studies. The definition, aetiology and diagnosis of ESUS are reassessed. Targeted diagnostics in ESUS patients can reduce the number of cryptogenic strokes by making a specific diagnosis.

Spontaneous echo contrast, left atrial appendage thrombus and stroke in patients undergoing transcatheter aortic valve implantation

AIMS

The relevance of spontaneous echo contrast (SEC) and left atrial appendage thrombus (LAAT) in patients undergoing transcatheter aortic valve implantation (TAVI) remains unclear. In this study, we aimed to assess the prevalence of SEC and LAAT and evaluate the impact on periprocedural outcome after TAVI.

METHODS AND RESULTS

A total of 2,549 consecutive patients underwent TAVI between 2008 and 2017. After exclusion of cases with insufficient imaging, concomitant procedures or severe intraprocedural complications, 1,558 cases were analysed. Three groups were defined according to (pre)thrombotic formations - moderate or severe SEC (n=89), LAAT (n=53), and reference (n=1,416). The primary outcome was disabling ischaemic stroke within 24 hours. The prevalence was 4.4% for LAAT and 5.4% for moderate/severe SEC. The primary outcome occurred more frequently in patients with moderate/severe SEC (6.8%) compared to the reference (2.1%) and LAAT (1.9%) groups (p=0.020). SEC was identified as an independent risk factor for the primary outcome (OR 3.54 [95% CI: 1.30-9.61], p=0.013). LAAT was associated with an impaired unadjusted one-year survival (43.4%) compared to the SEC (27.3%) and reference groups (18.7%, p<0.001).

CONCLUSIONS

SEC and LAAT were detected in a relevant number of patients undergoing TAVI. SEC may represent an important risk factor for intraprocedural stroke; increased mortality was observed in patients with LAAT.

Detection of Left Ventricular Thrombi on Cardiac Magnetic Resonance Viability Studies

Objective

To highlight detection of left ventricular thrombi on cardiac magnetic resonance (CMR) viability studies.

Method

This retrospective observational study was conducted in the Radiology Department at our Hospital in Dhahran, from April 2015-2019. All recently re-perfused (post-percutaneous coronary intervention/PCI) patients with ST-segment elevation myocardial infarctions (STEMI), having low ejection fractions (<40%), impaired LV functions or abnormal wall motions on transthoracic echocardiographies (TTEs), who underwent cardiac magnetic resonance (CMR) imaging viability studies were included. Patients with incomplete or limited studies (due to artifacts), previous coronary artery bypass graft (CABG), those who lost follow-ups, and those who were contraindicated or unfit for MRIs were excluded. An area of low signal intensity with no late gadolinium enhancement (LGE) was defined as thrombus on MR imaging, and two radiologists reached consensus report for the diagnoses. Patients with anterior or non-anterior wall MI were documented, and their ejection fractions were recorded. Percentage estimation of LV thrombi as detected on CMR studies was made. Any complications (like MI, stroke or death) that occurred within one year of diagnoses were documented. A Chi-square was used to determine association.

Results

Of the 125 patients, most were men (71.2%) with a mean age of 56.78 years. Eleven patients had left ventricular thrombi (8.8%), and most of these were anterior wall infarctions with low ejection fractions (<40%). Three out of 11 patients with LV thrombi developed complications versus 3 out of 114 without LV thrombi (P- value, .0005).

Conclusion

Left ventricular thrombi can be detected on cardiac viability studies in recently re-perfused STEMI patients and may possibly predict the risk of complications.

A pilot image interpretation teaching intervention to improve competence and confidence of radiographers to detect left ventricular thrombus in routine cardiac MRI scans

INTRODUCTION

Prompt diagnosis of left ventricular (LV) thrombus is clinically important, as it may require immediate anti-coagulation treatment. The aim of this study was to determine if a teaching intervention delivered by cardiovascular magnetic resonance (CMR) physicians would increase the CMR radiographers' ability to detect LV thrombus on a routine CMR scan.

METHODS

A cohort of 25 patients (14 with and 11 without LV thrombus) were identified. A multi-parametric CMR protocol had been performed in all patients. Ten radiographers reviewed the 25 randomised anonymised studies on a workstation, documenting the presence/absence of LV thrombus and their confidence level on a 7-point Likert scale. Two senior CMR fellows then delivered a focused teaching programme to the radiographers and all 25 randomised scans were reassessed 1 month after the teaching intervention.

RESULTS

Following dedicated training, there was a significant improvement in correct thrombus identification per radiographer (pre-training: 75 ± 6% vs post-training: 85 ± 6%, p = 0.009). The size of the thrombus was not associated with the likelihood of incorrectly identifying LV thrombus size prior to the training session (p = 0.2), but a trend was observed between smaller thrombus size and incorrect identifications post-training (p = 0.06). The radiographers' overall confidence in assessing the cases prior to the teaching session was high (5.6 ± 0.8 out of 7). Following the teaching session, self-reported confidence did not vary significantly (5.9 ± 0.7 out of 7, p = 0.42). When evaluating the teaching session, radiographers provided very positive feedback, rating the usefulness of the teaching intervention as highly educative (8.8 ± 0.4 out of 10).

CONCLUSIONS

This is the first study that has explored the ability and confidence of CMR radiographers in detecting LV thrombus on routine CMR scans as a result of the teaching intervention delivered by CMR physicians.

IMPLICATIONS FOR PRACTICE

A teaching intervention can improve CMR radiographers' diagnostic skills and diagnostic confidence.

Association Between Left Ventricular Ejection Fraction, Wall Motion Abnormality, and Embolic Stroke of Undetermined Source

Background

It is uncertain whether there is an association between left ventricular (LV) ejection fraction (LVEF) or LV wall motion abnormality and embolic stroke of undetermined source (ESUS).

Methods and Results

We performed a retrospective, cross‐sectional study of patients with acute ischemic stroke enrolled in the CAESAR (Cornell Acute Stroke Academic Registry) from 2011 to 2016. We restricted this study to patients with ESUS and, as controls, those with small‐ and large‐artery ischemic strokes. LVEF had to be above 35% to be considered ESUS. In a secondary analysis, we excluded patients with ESUS who had any evidence of ipsilateral carotid atherosclerosis. Multiple logistic regression was used to evaluate whether LVEF or LV wall motion abnormality was associated with ESUS. We performed a confirmatory study at another tertiary‐care center. We identified 885 patients with ESUS (n=503) or small‐ or large‐artery strokes (n=382). Among the entire cohort, LVEF was not associated with ESUS (odds ratio per 5% decrement in LVEF, 1.0; 95% CI, 1.0–1.1) and LV wall motion abnormality was not associated with ESUS (odds ratio, 0.9; 95% CI, 0.5–1.6). The results were identical in our confirmatory study. In our secondary analysis excluding ESUS patients with any evidence of ipsilateral carotid atherosclerosis, there was an association between LVEF and ESUS (odds ratio per 5% decrement in LVEF, 1.2; 95% CI, 1.0–1.5; P=0.04).

Conclusions

Among the entire cohort, no association existed between LVEF or LV wall motion abnormality and ESUS; however, after excluding ESUS patients with any evidence of ipsilateral carotid atherosclerosis, lower LVEF appeared to be associated with ESUS.

Embolic Stroke of Undetermined Source: Gateway to a New Stroke Entity?

Embolic stroke of unknown source (ESUS) is currently thought to represent a subpopulation of cryptogenic strokes defined by its embolic stroke pattern on imaging, and if after a carefully performed diagnostic evaluation, a specific, well-recognized cause of stroke has not been identified. The concept was primarily established to justify and enable the conduct of the ESUS trials, such as Randomized, Double-Blind, Evaluation in Secondary Stroke Prevention Comparing the Efficacy and Safety of the Oral Thrombin Inhibitor Dabigatran Etexilate versus Acetylsalicylic Acid in Patients with Embolic Stroke of Undetermined Source (RESPECT-ESUS) and New Approach Rivaroxaban Inhibition of Factor Xa in a Global Trial versus aspirin to Prevent Embolism in Embolic Stroke of Undetermined Source (NAVIGATE-ESUS). With both studies having neutral results, the question arises if the ESUS concept is misleading or rather a gateway for a modern understanding of stroke etiology. This review will analyze the background of the ESUS concept, overview the results and the impact of the recent multicenter trials and cohort studies, and discuss the definition, etiology, and diagnosis of ESUS.

Cardiac Imaging After Ischemic Stroke or Transient Ischemic Attack

PURPOSE OF REVIEW

Cardiac imaging after ischemic stroke or transient ischemic attack (TIA) is used to identify potential sources of cardioembolism, to classify stroke etiology leading to changes in secondary stroke prevention, and to detect frequent comorbidities. This article summarizes the latest research on this topic and provides an approach to clinical practice to use cardiac imaging after stroke.

RECENT FINDINGS

Echocardiography remains the primary imaging method for cardiac work-up after stroke. Recent echocardiography studies further demonstrated promising results regarding the prediction of non-permanent atrial fibrillation after ischemic stroke. Cardiac magnetic resonance imaging and computed tomography have been tested for their diagnostic value, in particular in patients with cryptogenic stroke, and can be considered as second line methods, providing complementary information in selected stroke patients. Cardiac imaging after ischemic stroke or TIA reveals a potential causal condition in a subset of patients. Whether systematic application of cardiac imaging improves outcome after stroke remains to be established.

Cardiac wall motion abnormality as a predictor for undetermined stroke with embolic lesion-pattern

OBJECTIVES

Several strokes of potential embolism do not clearly meet the definitions of embolic stroke with unknown source, cryptogenic stroke, or cardioembolic (CE) stroke. Considering the high mortality and recurrence of CE strokes, it is very important to detect treatable cardiac sources of embolism. Although regional wall motion abnormality (RWMA) of the left ventricle (LV) seems to be related to CE stroke, association between cerebral embolic risk and RWMA remains unclear. The purpose of this study was to investigate the influence of RWMA on undetermined stroke with embolic lesion-pattern (USELP).

PATIENTS AND METHODS

Among a total of 2327 patients with acute ischemic stroke, we excluded 148 patients without a transthoracic echocardiography (TTE). According to a stepwise approach, we excluded patients without an embolic lesion-pattern. Finally, we divided patients into two groups (USELP, 119, and non-embolic stroke, 1237). We classified patients' RWMAs into three major arterial territories according to the standard 17-segment model of TTE.

RESULTS

Among the included 1356 patients, those with USELP had larger internal dimension at diastole and systole in LV, reduced LV ejection fraction, increased E/A ratios, mitral valve disease, and RWMA. After adjusting for multiple variables, binary logistic regression revealed that RWMA was significantly associated with USELP (OR 7.02, 95 % CI: 3.51-14.01, p<0.001).

CONCLUSION

This study provides significant information to support that RWMA can be a predictor for undetermined embolic stroke. In this regard, RWMA were highly correlated with patients whose imaging supported an embolic source compared to those without this radiographic pattern.

Long-Term Embolic Outcomes After Detection of Left Ventricular Thrombus by Late Gadolinium Enhancement Cardiovascular Magnetic Resonance Imaging: A Matched Cohort Study

BACKGROUND

Late gadolinium enhancement (LGE) cardiovascular magnetic resonance (CMR) imaging is more sensitive than echocardiography for the detection of intracardiac thrombus because of its unique ability to identify thrombus based on tissue characteristics related to avascularity. The long-term prognostic significance of left ventricular (LV) thrombus detected by LGE CMR is unknown.

METHODS

We performed a matched cohort study of consecutive adult patients with LV thrombus detected by LGE CMR who were matched on the date of CMR, age, and LV ejection fraction to up to 3 patients without LV thrombus. We investigated the long-term incidence of a composite of embolic events: stroke, transient ischemic attack, or extracranial systemic arterial embolism. We also compared outcomes among patients with LV thrombus detected by LGE CMR stratified by whether the LV thrombus was also detected by echocardiography or not.

RESULTS

Of 157 LV thrombus patients, 155 were matched to 400 non-LV thrombus patients. During a median follow-up of 3.3 years, the cumulative incidence of embolism was significantly higher in LV thrombus patients compared with the matched non-LV thrombus patients (P<0.001), with annualized rates of 3.7% and 0.8% for LV thrombus and matched non-LV thrombus patients, respectively. LV thrombus was the only independent predictor of the composite embolic end point (hazard ratio, 3.99 [95% CI, 1.54-10.35]; P=0.004). The cumulative incidence of embolism was not different in patients with LV thrombus that was also detected by echocardiography versus patients with LV thrombus not detected by echocardiography (P=0.25).

CONCLUSIONS

Despite contemporary antithrombotic treatment, LV thrombus detected by LGE CMR is associated with a 4-fold higher long-term incidence of embolism compared with matched non-LV thrombus patients. LV thrombus detected by LGE CMR but not by echocardiography is associated with a similar risk of embolism as that detected by both LGE CMR and echocardiography.

Cardiac imaging after ischemic stroke : Echocardiography, CT, or MRI?

About 20–25% of all ischemic strokes are of cardioembolic etiology, with atrial fibrillation and heart failure as the most common underlying pathologies. Diagnostic work-up by noninvasive cardiac imaging is essential since it may lead to changes in therapy, e.g., in—but not exclusively—secondary stroke prevention. Echocardiography remains the cornerstone of cardiac imaging after ischemic stroke, with the combination of transthoracic and transesophageal echocardiography as gold standard thanks to their high sensitivity for many common pathologies. Transesophageal echocardiography should be considered as the initial diagnostic tool when a cardioembolic source of stroke is suspected. However, to date, there is no proven benefit of transesophageal echocardiography-related therapy changes on the main outcomes after ischemic stroke. Based on the currently available data, cardiac computed tomography and magnetic resonance imaging should be regarded as complementary methods to echocardiography, providing additional information in specific situations; however, they cannot be recommended as first-line modalities.

Embolic stroke of undetermined source (ESUS) cohort of Brazilian patients in a university hospital

OBJECTIVE

Embolic stroke of undetermined source (ESUS) is an important group of cryptogenic strokes that are in evidence due recent ongoing trials. We reviewed medical records at discharge from the stroke unit of all patients who met ESUS criteria and attended our institution between February 2016 and July 2017. Among 550 stroke patients, 51 had ESUS. We found that hypertension (60%), diabetes mellitus (34%), and smoking (36%) were the most prevalent risk factors. The mean National Institutes of Health Stroke Scale (NIHSS) scores were 7 at admission and 4 at discharge, while median scores on the modified Rankin scale were 0 and 2 at admission and discharge, respectively. Our sample had similar ages, risk factors prevalence and NIHSS scores at admission and discharge when compared with European and North American cohorts. Although a small cohort, our study suggests that the ESUS population is similar in countries with different health financing.