Potential Cardioembolic Source Research Articles

Abstract P603: Atrial Cardiopathy and Brain Infarction in Multiple Vascular Territories in the ARCADIA Trial

Introduction: Some embolic strokes of undetermined source (ESUS) are likely caused by occult cardiac embolism. One potential cardioembolic source is atrial cardiopathy without atrial fibrillation (AF). Patients with cardiac embolism more often have brain infarcts in multiple vascular territories than those with stroke mechanisms not involving a central embolic source. Hypothesis: In patients with ESUS, atrial cardiopathy is associated with brain infarction in multiple vascular territories. Methods: The ARCADIA trial is enrolling ESUS patients, screening them for atrial cardiopathy, and randomly assigning those with atrial cardiopathy to aspirin or apixaban. In the trial, atrial cardiopathy is defined as ≥1 of the following: P-wave terminal force >5,000 μV*ms in ECG lead V 1 , serum NT-proBNP >250 pg/mL, and left atrial diameter index ≥3 cm/m 2 on echocardiogram. Site investigators report whether the index CT or MRI showed brain infarction in the left carotid, right carotid, or posterior circulation, or some combination. In this analysis, our primary outcome was brain infarction in more than one of these three vascular territories. Our secondary outcome was infarction in both the left and right carotid territories. Results: Among 1,707 ESUS patients enrolled in ARCADIA, 679 (39.8%) met the trial’s randomization criteria for atrial cardiopathy and 213 (12.5%) had multi-territorial brain infarcts. The prevalence of brain infarction in more than one vascular territory was 14.0% in those with atrial cardiopathy versus 11.5% in those without (prevalence ratio, 1.22; 95% CI, 0.95-1.57). The prevalence of brain infarction in both the left and right carotid territories was 9.1% in those with atrial cardiopathy versus 7.4% in those without (prevalence ratio, 1.24; 95% CI, 0.90-1.70). Conclusions: These preliminary analyses from ARCADIA suggest a possible association between atrial cardiopathy and brain infarction in multiple vascular territories, but further analysis of a larger sample is needed to conclusively test whether our atrial cardiopathy definition is associated with the classic neuroimaging profile of cardiac embolism.

Double-Chamber Left Ventricle as a Potential Cardioembolic Source in Acute Ischemic Stroke.

Double-Chamber Left Ventricle as a Potential Cardioembolic Source in Acute Ischemic Stroke.

Diagnostic accuracy of acute infarcts in multiple cerebral circulations for cardioembolic stroke: Literature review and meta-analysis

ObjectiveTo determine the diagnostic value of acute infarcts in multiple cerebral circulations (AIMCC) on MRI diffusion-weighted imaging (DWI) for cardioembolism (CE) stroke subtype in adult patients hospitalized with acute ischemic stroke, we conducted a systematic literature review and meta-analysis. MethodsMEDLINE was searched via PubMed for articles reporting patients hospitalized with acute ischemic stroke with MRI DWI categorized as AIMCC vs other and use of Trial of Org 10172 in Acute Stroke Treatment (TOAST) Criteria for cardioembolism subtype. Measures of diagnostic accuracy were calculated from the retrieved studies. ResultsSeven eligible articles comprised 5813 patients. Bivariate random effects models estimated sensitivity 0.19 (95% CI, 0.13 to 0.27), specificity 0.89 (0.86 to 0.91), positive predictive value 0.37 (0.30 to 0.45), negative predictive value 0.76 (0.7 to 0.82), positive likelihood ratio 1.70 (1.13 to 2.57) and negative likelihood ratio 0.91 (0.83 to 1). InterpretationThe pattern of AIMCC on DWI is of limited diagnostic value. It is not sufficiently accurate to exclude cardiac pathology by a negative test nor does a positive test indicate a major increase in the probability of identifying a potential cardioembolic source.

Transesophageal echocardiography for aortic arch atheromas in patients with cryptogenic stroke/transient ischemic attack – An underutilized entity

Introduction: Large aortic arch atheromas (≥4 mm) and complex and mobile aortic atheromas have been associated with ischemic brain stroke in various previous studies. Transesophageal echocardiography (TEE) is the imaging modality of choice, however, is an underutilized investigation in routine clinical practice. We sought out to find the prevalence and severity of aortic arch atheromas in patients with cryptogenic stroke/transient ischemic attack (TIA) at a tertiary care center. Patients and Methods: One hundred and eighty-eight consecutive stroke patients were screened for stroke risk factors. Sixty-one patients were found to have stroke without obvious cause (cryptogenic), 52 patients underwent TEE, four patients were further excluded after evidence of potential cardioembolic source in TEE, and finally, data of 48 patients with cryptogenic stroke were analyzed. Results: We found that one-third of the patients (n = 16, 33.3%) had aortic atheromas and half of them (n = 8, 16.4%) had atheromas ≥4 mm. Diabetes, dyslipidemia, and smoking status were individually associated with a higher prevalence of aortic plaques in our study (P = 0.03). The frequency of aortic plaques was significantly higher in patients with ischemic brain infarction than in TIA (P = 0.01). Large atheromas (≥4 mm) were significantly associated with more severe clinical illness as assessed by the National Institute of Health Stroke Scale, longer hospital stay, and death (P Conclusions: In the present observational study at a tertiary care center, we found that the relevant aortic atheromas in patients with cryptogenic stroke are fairly common and are associated with adverse clinical events. The diagnosis of aortic atheromas should be sought actively by TEE in patients with cryptogenic stroke or in patients with recurrent embolic events and multiple risk factors. Antiplatelet agents and statins are the mainstay of therapy. Anticoagulation is reasonable in selected high-risk patients. Future randomized trials of direct oral anticoagulants compared to antiplatelet therapy in patients with complex aortic atheromas are anticipated to guide the clinicians.

Thrombus in transit through a patent foramen ovale: An unusual cause of cardiac embolism

A 78-year-old woman with a history of transient ischemic attack was admitted for sudden aphasia. In order to assess the potential cardioembolic source an echocardiogram was performed, which revealed a large mass consistent with a thrombus in transit through a patent foramen ovale. Because of the high risk of systemic embolism, emergent surgical thrombectomy was performed with the intention to discharge the patient safely without any new embolic events. This case report highlights the importance of echocardiography in the evaluation of cardioembolic stroke and the requirement of an emergent approach in case of impending paradoxical embolism.

Embolic Pattern of Stroke Associated with Cardiac Wall Motion Abnormalities; Narrowing the Embolic Stroke of Undetermined Source Category

BackgroundThere is ambiguity regarding the role of left ventricle wall motion abnormalities (LVWMAs) as a potential cardioembolic source in patients, who satisfy embolic stroke of undetermined source (ESUS) criteria. Methods and resultsWe analyzed prospectively collected data in 345 acute stroke patients, 185 (53.6%) stroke with atrial fibrillation (SwAF), and 160 (46.4%) stroke with LVWMA. LVWMA were younger (P = .003), had significantly higher frequency of stroke risk factors and lower ejection fraction (P < .001). No significant difference was found between the stroke pattern in SwAF and LVWMA except focal cortical, cortical-subcortical lesions were more frequent in LVWMA (P = .002). Mean wall motion score index (WMSI) was 1.523 (range 1.05-2.71) without any correlation between the severity of WMSI and multiple strokes (P = .976). In subgroup analyses vertical basal WMSI (P = .030) and vertical mid cavity WMSI (P = .010) was significantly related to branch arterial stroke. LVWMA 94 (65%) patients were on antiplatelet/anticoagulation compared to 47 (52.4%) with atrial fibrillation (AF), with no significant difference in stroke recurrence during 4 years follow-up (P = .15). ConclusionsPatients with LVWMA who satisfy ESUS criteria, have stroke pattern on diffusion-weighted magnetic resonance imaging and risk of stroke recurrence similar to AF-related stroke despite being on appropriate antiplatelet medications. Further studies with anticoagulation therapy may be required in this group of patients to improve the high risk of recurrent stroke.

Transesophageal echocardiographic thromboembolic risk is associated with smoking status in patients with atrial fibrillation

BackgroundSmoking is a risk factor for cardiovascular diseases, but it is unclear whether smoking status, including environmental tobacco smoke, increases stroke risk in patients with atrial fibrillation (AF). Abnormalities of the left atrium (LA) and aortic atherosclerosis, as detected by transesophageal echocardiography (TEE), are risk factors for stroke and thromboembolism in AF patients. We investigated the impact of smoking status on thromboembolic risk by TEE in patients with nonvalvular AF. MethodsIn 122 patients with AF (mean age, 63 years; chronic AF 50%) who underwent TEE before catheter ablation of AF or for detection of the potential cardioembolic source, urinary concentrations of cotinine and clinical variables including smoking status and the CHA2DS2-VASc score were determined. ResultsSevere aortic atherosclerosis and increased aortic wall thickness were more frequently detected by TEE in current smokers than in non-smokers (p<0.05), though these findings did not significantly differ between non-smokers and environmental smokers. Patients in AF rhythm during TEE, who were environmental smokers and at relatively low risk, as stratified by their CHA2DS2-VASc score (≤ 2), showed lower LA appendage flow velocity than those without environmental smoking (47±22 vs. 34±13cm/sec, p<0.05). ConclusionsTEE findings indicated that smoking status could be associated with thromboembolic risk in patients with AF.

Diagnostic Impact of Transesophageal Echocardiography in Patients with Acute Cerebral Ischemia.

Transesophageal echocardiography (TEE) is the diagnostic gold standard for the detection of structural heart diseases as potential sources of cardiac emboli in patients with acute cerebral ischemia. We sought to determine the diagnostic yield of TEE in patients with acute ischemic stroke or transient ischemic attack (TIA). We retrospectively analyzed consecutive patients with acute cerebral ischemia who were admitted to our hospital between October 2008 and December 2011. TEE reports were screened for detection of cardiac source of embolism judged by the recommendation to change medical management. We performed univariate and multivariate analyses to identify predictors of clinically relevant TEE findings among baseline characteristics. Of 3314 patients with ischemic stroke or TIA, TEE was performed in 791 (24%) patients (mean age 64 ± 13 years, 589 [74%] ischemic stroke, 202 [26%] TIA). A potential cardioembolic source was found in 71 (9%) patients with patent foramen ovale with atrial septal aneurysm being the most common finding (24/71 patients, 34%). In multivariate analysis, peripheral vascular disease (OR 2.57; 95%CI 1.00-6.61), imaging evidence of infarction in multiple locations (OR 4.13; 95%CI 1.36-12.58), and infarction in the posterior circulation (OR 2.11; 95%CI 1.01-4.42) were associated with the identification of a potential cardioembolic source with TEE. TEE identified a potential structural cardioembolic source in nearly 10% of our selected patient population with acute ischemic stroke or TIA, thus underlining its diagnostic value. Our data suggest that patients with hitherto unknown stroke etiology should be considered for additional TEE.

The causality quandary in a patient with stroke, Takotsubo syndrome and severe coronary artery disease

Takotsubo-like left ventricular dysfunction syndrome (TLVDS) and acute coronary syndrome have almost always the same clinical presentation and ECG findings. Both diseases may become a potential cardioembolic source to the cerebrovascular system. Stroke has been linked to TLVDS either as the trigger or as a complication. We report on a 67-year-old female patient who presented with an acute ischemic stroke confirmed by computed tomographic scan of the brain. She also had electrocardiographic features and laboratory findings suggestive of both acute myocardial infarction (AMI) and TLVDS. Coronary angiography revealed severe coronary artery stenoses but the coronary lesions did not have any of the features suggestive of an acute pathology. Echocardiography and left ventriculography showed a striking apical ballooning of the left ventricle, which resolved completely within 1 week, a clinical picture and course typical for TLVDS. There were no signs of left ventricular thrombus. A few burning questions arose from this case: what was the acute cardiac disease - TLVDS or AMI? Which disease came first - the stroke or the acute cardiac illness? An intricate cause-effect relationship is discussed; and finally, does an obstructive coronary artery disease rule out TLVDS?

Computed Tomography and Echocardiography together Reveal More High-Risk Findings than Echocardiography Alone in the Diagnostics of Stroke Etiology

Background: Cardioembolic stroke carries a major risk of stroke recurrence, which can be markedly reduced by early initiation of appropriate secondary prevention. We investigate whether combined examination of the heart, aorta, and cervicocranial arteries with computed tomography (CACC-CT) may improve the diagnosis of stroke etiology. Methods: Patients with suspected cardiogenic ischemic stroke or transient ischemic attack (n = 140; mean age 60 ± 10 years; 95 males) underwent CACC-CT and standard diagnostics including transthoracic and transesophageal echocardiography (TTE/TEE). Patients with atrial fibrillation were excluded because cardiac imaging will not affect to anticoagulant treatment. Imaging findings with a potential cardioembolic source were analyzed. Aortic and cardiac risk findings were evaluated independently. Consensus reading of 2 experts using the findings of both approaches and complemented by cardiac MRI when needed served as the reference standard. Results: In 101 patients (72%) the clinical diagnosis was stroke, and transient ischemic attack was confirmed in the remaining patients. Imaging findings associated with highly increased cardioembolic risk were detected in 22 patients (16%). Nine high-risk findings in 140 patients were found by TTE/TEE and this number rose to 25 high after performing both echocardiography and CACC-CT. No difference was found between CACC-CT and TTE/TEE in detecting patients with of at least one high-risk findings (sensitivity 68 vs. 41%, p = 0.052; specificity 98 vs. 99%; overall accuracy 94 vs. 90%). Combined use of CACC-CT and TTE/TEE was more sensitive than TTE/TEE alone for detecting patients with at least one cardiac or aortic high-risk finding (sensitivity 91 vs. 41%, p < 0.001; specificity 98 vs. 99%; overall accuracy 97 vs. 90%). TTE/TEE was insufficient for diagnosing myocardial infarction with left ventricular aneurysm, whereas the accuracy of CACC-CT was high. In 9 patients (6%) with normal or mild hypokinesia in TTE/TEE, CACC-CT and MRI showed myocardial infarction large enough to indicate anticoagulant therapy. In contrast, CACC-CT was not suitable for diagnosing small left artrial thrombi, patent foramen ovale or to measure left ventricular ejection fraction. Conclusion: CACC-CT and TTE/TEE alone show limited accuracy for the diagnostics of stroke etiology. Therefore, CACC-CT could be a valuable tool in patients with cryptogenic stroke despite standard stroke diagnostics.

Abstract WP34: Factors Associated with Reduced use of Stroke MRI: an Analysis of Practice Patterns

Background: Guidelines support the use of Magnetic Resonance Imaging (MRI) in the evaluation of acute stroke, however the perceived value of MRI information to providers in different clinical scenarios is not known. We aimed to identify patient characteristics associated with lower MRI use as means of identifying possible clinical scenarios where providers may perceive MRI to be less valuable. Methods: Stroke hospitalizations (principal ICD-9-CM 433.x1, 434.x1, 436) were identified from the State Inpatient Databases (SID) from 2003-2009 for 12 states. MRI utilization was identified using revenue codes and ICD-9 procedure codes. Patient characteristics were abstracted from the hospitalization record. Multi-level logistic regression with a random hospital-level intercept was used to estimate the association between patient characteristics (demographics, vascular risk factors, stroke mimics, comorbidities, regional socioeconomic status) and MRI. Effect sizes were estimated using posterior probabilities with all covariates held at their means. Sensitivity analyses accounting for the distribution of MRI contraindications were performed. Results: 670,309 hospitalizations were included in our sample; 51% of the population received MRI. From the model (area under ROC 0.82), age and potential cardioembolic source (atrial fibrillation, congestive heart failure, myocardial infarction) were associated with a lower probability of MRI utilization (table). The predicted probability of MRI in a 50 year old was 63.7% (95% CI 61.5%-65.9%) compared to 41.6% (39.4%-43.9%) in an 80 year-old. In sensitivity analysis, the association between cardioembolic sources and lower MRI use remained significant after accounting for extreme assumptions about the distribution of MRI contraindications. Conclusions: In routine care, MRI may have less perceived value by providers in stroke patients who are older and have a potential cardioembolic source.

Papel do ecocardiograma transesofágico na avaliação e orientação terapêutica dos doentes com evento cerebral isquémico agudo até aos 65 anos de idade

Introduction Ischemic stroke is the leading cause of mortality in Portugal, with around 30 to 50 % of cases being of cardioembolic etiology. Transesophageal echocardiography (TEE) has assumed growing importance in the detection of cardiac sources of embolism. However, there is controversy regarding the implications of TEE findings for the therapeutic approach to patients with ischemic stroke. Objectives To analyze TEE findings in the diagnostic work-up of patients with ischemic cerebral events and to determine their influence on therapeutic strategy. Methods We retrospectively studied patients with stroke or transient ischemic attack (TIA) before the age of 65, of no apparent cause after carotid ultrasound, electrocardiogram and transthoracic echocardiography, who underwent TEE between 1992 and 2009. The following diagnoses on TEE were considered as potential embolic sources: atrial septal defect; patent foramen ovale (PFO); atrial septal aneurysm (ASA); vegetations; tumors; intracavitary thrombi; and aortic plaques >2 mm (ascending aorta and arch). Results We analyzed 294 patients, mean age 45 years, 56.8 % men. TEE revealed a potential cardioembolic source in 36.7 % of the patients, PFO and ASA being the most frequent. Throughout the period considered, there was an increase in the number of exams performed, as well as in diagnoses, mainly PFO and ASA. Comparison of patients with and without a diagnosis on TEE showed that the former were older and were more often prescribed oral anticoagulation. By multivariate analysis, the presence of a positive TEE finding was shown to be an independent predictor of treatment with oral anticoagulation (OR=2.48; CI 95%: 1.42–4.34; p=0.001). Conclusion In the population under analysis, TEE was useful in identifying potential cardioembolic sources and infl uenced the therapeutic strategy.

Role of transesophageal echocardiography in the assessment and therapeutic management of patients with acute ischemic cerebral events before the age of 65

IntroductionIschemic stroke is the leading cause of mortality in Portugal, with around 30 to 50% of cases being of cardioembolic etiology. Transesophageal echocardiography (TEE) has assumed growing importance in the detection of cardiac sources of embolism. However, there is controversy regarding the implications of TEE findings for the therapeutic approach to patients with ischemic stroke. ObjectivesTo analyze TEE findings in the diagnostic work-up of patients with ischemic cerebral events and to determine their infl uence on therapeutic strategy. MethodsWe retrospectively studied patients with stroke or transient ischemic attack (TIA) before the age of 65, of no apparent cause after carotid ultrasound, electrocardiogram and transthoracic echocardiography, who underwent TEE between 1992 and 2009. The following diagnoses on TEE were considered as potential embolic sources: atrial septal defect; patent foramen ovale (PFO); atrial septal aneurysm (ASA); vegetations; tumors; intracavitary thrombi; and aortic plaques >2mm (ascending aorta and arch). ResultsWe analyzed 294 patients, mean age 45 years, 56.8% men. TEE revealed a potential cardioembolic source in 36.7% of the patients, PFO and ASA being the most frequent. Throughout the period considered, there was an increase in the number of exams performed, as well as in diagnoses, mainly PFO and ASA. Comparison of patients with and without a diagnosis on TEE showed that the former were older and were more often prescribed oral anticoagulation. By multivariate analysis, the presence of a positive TEE finding was shown to be an independent predictor of treatment with oral anticoagulation (OR=2.48; CI 95%: 1.42-4.34; p=0.001). ConclusionIn the population under analysis, TEE was useful in identifying potential cardioembolic sources and influenced the therapeutic strategy.

Can ABCD2 score predict the need for in-hospital intervention in patients with transient ischemic attacks?

BackgroundThe ABCD2 score is increasingly being used to triage patients with transient ischemic attack (TIA). Whether the score can predict the need for in-hospital intervention (IHI), other than initiation of antiplatelets and statins, is unknown.AimsThe ability of the ABCD2 score to predict IHI would strengthen the rationale to use it as a decision-making tool. We thus conducted this study to investigate the relationship between the ABCD2 score and IHI.MethodsWe analyzed prospectively collected data from consecutive TIA patients over 12 months. We determined ABCD2 upon admission and collected the results of in-hospital evaluation, treatments initiated during hospitalization, and follow-up status. We defined IHI as arterial revascularization or anticoagulation required during admission. We used chi-square for trend to examine the association between ABCD2 and IHI.ResultsWe studied 121 patients. Fourteen (12%) had small infarcts on diffusion magnetic resonance imaging; 38 (31%) had a new risk factor recognized during admission [hyperlipidemia (n = 9), hypertension (1), diabetes (1), carotid stenosis ≥ 50% (16), other arterial occlusive lesions (7), and potential cardioembolic source (4)]. Their percentages increased with higher ABCD2 scores. However, among 12 patients (10%) with IHI, ABCD2 score categories were equally distributed (10% in 0–3, 9% in 4–5, and 10% in 6–7; p = 0.8). One patient (0.8%) worsened during hospitalization; none had a stroke during follow-up.ConclusionPatients with an ABCD2 score ≤ 3 had an equal chance of requiring IHI as those with a score of 4–7. The decision to admit TIA patients based on the ABCD2 score alone is not supported by our experience and requires further study.

Late device thrombosis after atrial septal defect closure

A 62-year-old woman with a history of transcatheter atrial septal defect (ASD) closure using a Cardioseal/Starflex® device was admitted for recurrent transient ischaemic attacks 3 years after closure. A transoesophageal echocardiogram (TEE) revealed a large, mobile, thrombus-like structure attached to the left-atrial side of the device as a potential cardio-embolic source. There …

Influence of transoesophageal echocardiography on therapy and prognosis in young patients with TIA or ischaemic stroke

Objective. To determine the influence of transoesophageal echocardiography (TEE) on therapy and prognosis in patients with cryptogenic transient ischaemic attack (TIA) or ischaemic stroke under the age of 50 years.Methods and results. We evaluated all patients aged 50 and under who were referred to our university hospital for cryptogenic TIA or ischaemic stroke during the period 1 January 1996 to 31 December 2004. All patients underwent both transthoracic echocardiography (TTE) and TEE. Patients with known pre-existent heart disease, such as atrial fibrillation, were excluded. Eighty-three patients with TIA (22) and ischaemic stroke (61) were enrolled. Mean age was 39+/-8 years (range 18 to 50). In 30% of the patients TEE detected one or more potential cardioembolic source, compared with 10% for TTE (p=0.003). Standard treatment (aspirin 38 mg daily) was changed in 7% of the patients due to the TEE findings. Complete followup was obtained in 93% with an average of 5+/-3 years. Twelve recurrences occurred; two out of six patients (33%) with therapy change and ten out of 71 (14%) of the patients without therapy change had a recurrent TIA or ischaemic Stroke.Conclusion. In patients with cryptogenic TIA or ischaemic stroke, TEE is superior to TTE in the detection of a potential cardiac source of embolism. However, findings obtained by TEE only influence the already initiated treatment in a small percentage of patients. The recurrence rate both in the group with and without therapy change is high. (Neth Heart J 2009;17:373-7.).

Sensorimotor stroke; clinical features, MRI findings, and cardiac and vascular concomitants in 32 patients.

Sensorimotor stroke (SMS) is often included among the lacunar syndromes, although the underlying cause of this stroke-subtype is less well documented. To this end we analysed 32 patients presenting with a sensorimotor syndrome. The study protocol included vascular risk factors, echocardiography, Doppler sonography of carotid arteries, CT scan and MRI of the brain. There were 23 men and 9 women, mean age 65.7 years. Hypertension was present in 28% and diabetes in 19%. In all, 63% had sensorimotor deficit of faciobrachiocrural areas and 37% had faciobrachial or brachiocrural deficits. MRI disclosed a presumably relevant infarct in 26 patients (81%); 20 patients (62%) localized to the territory of small perforating arteries, 3 patients (9.5%) in the internal borderzone, and 3 patients (9.5%) in cortical territories. Eight of 20 deep infarcts were larger than 15 mm. No hemorrhage or non-vascular lesion was found. A potential cardioembolic source was present in 5 patients (16%), whereas 2 patients (6%) had an ipsilateral carotid stenosis >50%. Small vessel disease was the most likely cause in 69% of our patients with SMS, whereas 31% had a potential cardioembolic source, large artery disease or infarcts not compatible with perforating artery disease.

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Tissue Plasminogen Activator −7351C/T Polymorphism and Lacunar Stroke

To the Editor: Jannes et al1 reported that a polymorphism in the tissue plasminogen activator (tPA) gene (−7351C/T) was associated with ischemic stroke in an Australian population. Stratification for stroke subtype demonstrated an association with lacunar infarction (OR: 2.7; 95% CI, 1.1 to 6.7), but not with other stroke subtypes. The authors interpreted this result as providing evidence that fibrinolytic factors play an important role in maintaining small vessel patency. The polymorphism is located within the binding site for the transcription factor Sp1, in the enhancer region of the tPA gene,1 and the TT genotype has been associated with significantly reduced vascular tPA release rates.2 This association could give clues to the pathogenesis of lacunar stroke, but first replication in independent populations is important, particularly because the original association was found in a small sample size, with only 43 patients in the lacunar subgroup. Therefore, we attempted to replicate it in a prospectively collected group of patients with well-phenotyped lacunar stroke. In addition, we determined whether the polymorphism predisposed to 1 particular type of lacunar stroke. It has been suggested that patients with larger lacunar infarcts (isolated lacunar infarction [ILI]) without leukoaraiosis may have microatheroma at the origins and proximal portions of the perforating arteries. In contrast, patients with lacunar infarction and confluent leukoaraiosis (ischemic leukoaraiosis [ILA]) may have a diffuse arteriopathy affecting the smaller perforating vessels.3 Previous studies have suggested different genetic associations in the 2 groups.4 Three hundred …

Differentiation between true microembolic signals and artefacts using an arbitrary sample volume

We evaluated a new discrimination technique between microemboli (MES) and artefact signals. Monitoring was performed over the middle cerebral artery (55 mm) and the brain parenchyma (29 mm). Intensity changes were expressed as percent of change compared to the value measured in the proximal depth. The cut-off value providing the highest sensitivity and specificity in the differentiation was evaluated using 250 MES and 250 artefact signals, and subsequently analysed in the first part of the study. Intensity values derived from the distal depth were subsequently evaluated in 10 patients undergoing cardiac surgery and 45 patients with potential arterial or cardioembolic source. Intensity changes of 87% (84%–90%) and −58% (−71%–−48%) were measured in the initial 500 signals for MES and artefact signals, respectively. The best intensity cut-off value was calculated at 27%. This value was subsequently applied to a total of 1858 MES and 1958 artefacts, resulting to sensitivity and specificity of 96% and 98%, respectively. The proposed technique provided adequate results, warranting further evaluation.