Frequency and Significance of Cardiac Sources of Embolism in the TOAST Classification

Preprocedural determination of an occlusion pathomechanism in endovascular treatment of acute stroke: a machine learning-based decision

OBJECTIVE

To evaluate whether an occlusion pathomechanism can be accurately determined by common preprocedural findings through a machine learning-based prediction model (ML-PM).

METHODS

A total of 476 patients with acute stroke who underwent endovascular treatment were retrospectively included to derive an ML-PM. For external validation, 152 patients from another tertiary stroke center were additionally included. An ML algorithm was trained to classify an occlusion pathomechanism into embolic or intracranial atherosclerosis. Various common preprocedural findings were entered into the model. Model performance was evaluated based on accuracy and area under the receiver operating characteristic curve (AUC). For practical utility, a decision flowchart was devised from an ML-PM with a few key preprocedural findings. Accuracy of the decision flowchart was validated internally and externally.

RESULTS

An ML-PM could determine an occlusion pathomechanism with an accuracy of 96.9% (AUC=0.95). In the model, CT angiography-determined occlusion type, atrial fibrillation, hyperdense artery sign, and occlusion location were top-ranked contributors. With these four findings only, an ML-PM had an accuracy of 93.8% (AUC=0.92). With a decision flowchart, an occlusion pathomechanism could be determined with an accuracy of 91.2% for the study cohort and 94.7% for the external validation cohort. The decision flowchart was more accurate than single preprocedural findings for determining an occlusion pathomechanism.

CONCLUSIONS

An ML-PM could accurately determine an occlusion pathomechanism with common preprocedural findings. A decision flowchart consisting of the four most influential findings was clinically applicable and superior to single common preprocedural findings for determining an occlusion pathomechanism.

Effect of Truncal-Type Occlusion Based on Multiphase or Single-Phase Computed Tomographic Angiography in Predicting Intracranial Atherosclerotic Stenosis-Related Acute Middle Cerebral Artery Occlusion

OBJECTIVE

To investigate whether truncal-type occlusion based on multiphase computed tomographic angiography (mpCTA) was more effective for predicting intracranial atherosclerotic stenosis-related occlusion (ICAS-O) than occlusion type based on single-phase computed tomographic angiography (spCTA) in patients with acute ischemic stroke with large-vessel occlusion (AIS-LVO) in the middle cerebral artery (MCA).

METHODS

Data were retrospectively collected from 72 patients with AIS-LVO in the MCA between January 2018 and December 2019. The occlusion types included truncal-type and branching-site occlusions. The association between ICAS-O and occlusion type based on the 2 computed tomographic angiography patterns was analyzed, and receiver operating characteristic curves were plotted for assessment. The areas under the curve were compared to determine the difference between the predictive powers of truncal-type occlusion based on mpCTA and spCTA.

RESULTS

Among the 72 patients, 16 were classified as having ICAS-O and 56 as having embolisms. In univariate analysis, truncal-type occlusion was significantly associated with ICAS-O (P < 0.001 for mpCTA and P = 0.001 for spCTA). After multivariable analysis, truncal-type occlusion based on both mpCTA and spCTA remained independently associated with ICAS-O (P = 0.002 for mpCTA and P = 0.029 for spCTA). The areas under the curve were 0.821 for mpCTA and 0.683 for spCTA; this difference was statistically significant (P = 0.024).

CONCLUSIONS

In patients with AIS-LVO in the MCA, truncal-type occlusion based on mpCTA enables more accurate detection of ICAS-O than that based on spCTA.

Imaging of the Left Atrial Appendage Before Occluder Device Placement: Evaluation of Virtual Monoenergetic Images in a Single-Bolus Dual-Phase Protocol

PURPOSE

Preimplantation cardiac computed tomography (CT) for assessment of the left atrial appendage (LAA) enables correct sizing of the device and the detection of contraindications, such as thrombi. In the arterial phase, distinction between false filling defects and true thrombi can be hampered by insufficient contrast medium distribution. A delayed scan can be used to further differentiate both conditions, but contrast in these acquisitions is relatively lower. In this study, we investigated whether virtual monoenergetic images (VMI) from dual-energy spectral detector CT (SDCT) can be used to enhance contrast and visualization in the delayed phase.

MATERIALS AND METHODS

Forty-nine patients receiving SDCT imaging of the LAA were retrospectively enrolled. The imaging protocol comprised dual-phase acquisitions with single-bolus contrast injection. Conventional images (CI) from both phases and 40-keV VMI from the delayed phase were reconstructed. Attenuation, signal-, and contrast-to-noise ratios (SNR/CNR) were calculated by placing regions-of-interest in the LAA, left atrium, and muscular portion of interventricular septum. Two radiologists subjectively evaluated conspicuity and homogeneity of contrast distribution within the LAA.

RESULTS

Contrast of the LAA decreased significantly in the delayed phase but was significantly improved by VMI, showing comparable attenuation, SNR, and CNR to CI from the arterial phase (attenuation/SNR/CNR, CI arterial phase: 266.0 ± 117.0 HU/14.2 ± 7.2/6.6 ± 3.9; CI-delayed phase: 107.6 ± 35.0 HU/5.9 ± 3.0/1.0 ± 1.0; VMI delayed phase: 260.3 ± 108.6 HU/18.2 ± 10.6/4.8 ± 3.4). The subjective reading confirmed the objective findings showing improved conspicuity and homogeneity in the delayed phase.

CONCLUSIONS

The investigated single-bolus dual-phase acquisition protocol provided improved visualization of the LAA. Homogeneity of contrast media was higher in the delayed phase, while VMI maintained high contrast.

The significance of the morphology-voltage-P-wave duration (MVP) ECG score for prediction of in-hospital and long-term atrial fibrillation in ischemic stroke

BACKGROUND

Atrial fibrillation (AF) is the most common preventable cause of stroke. Diagnosis of new AF is frequent after acute ischemic stroke (AIS). We aimed to evaluate the predictive value of the recently developed morphology-voltage-P-wave duration (MVP) ECG risk score for in-hospital and long-term AF diagnosis following AIS.

MATERIAL AND METHODS

In this observational investigation, we evaluated the ability of the MVP ECG risk score to predict AF in 266 consecutive patients with AIS. The study population was divided into three groups according to their calculated MVP ECG risk score on admission electrocardiography. The groups were compared in terms of their predictive value for in-hospital and long-term AF diagnosis.

RESULTS

After adjustment for confounding baseline variables, MVP ECG risk score 5-6 group had 13.2 times higher rates of in-hospital AF compared to MVP ECG risk score 0-2 group, which was used as the reference group. For long-term follow-up, MVP ECG risk score 5-6 group had 5.2 times higher rates of long-term AF compared to MVP ECG risk score 0-2 group. A ROC analysis showed that the optimal cut-off value of the MVP ECG risk score to predict in-hospital AF was 4 with 78% sensitivity and 76% specificity (AUC: 0.80; 95% CI: 0.64-0.96; p < 0.001), the optimal cut-off value of the MVP ECG risk score to predict long-term AF was 3 with 85% sensitivity and 59% specificity (AUC: 0.81; 95% CI: 0.76-0.86; p < 0.001).

CONCLUSION

The MVP ECG risk score, which can be easily calculated from a surface ECG, can be used to guide who needs stricter monitoring for the diagnosis of long-term AF in patients with AIS.

Presence of Atrial Fibrillation in Stroke Patients With Patent Foramen Ovale: Systematic Review and Meta-Analysis

Purpose: Patent foramen ovale (PFO) is associated with ischemic stroke, especially in patients with embolic stroke of undetermined source. This study aims to evaluate the presence of atrial fibrillation (AF) in ischemic stroke patients with PFO. Methods: We systematically searched EMBASE and MEDLINE databases on May 21, 2020 for studies that analyzed the presence of AF in patients with PFO. The primary outcome was the presence of AF in patients with PFO compared with those without. Outcomes were pooled using a random-effects model using the method of DerSimonian and Laird. We recorded demographic characteristics and the methods used for AF detection in the studies included (unspecified, history/medical records review, ECG, Holter monitor, or loop recorder). Results: A total of 14 studies and 13,245 patients fulfilled the entry criteria. The average age was 61.2 years and 41.3% of the participants were female. There was a lower risk of AF in patients with PFO compared with those without (RR 0.52, 95% confidence interval, 0.41-0.63, p < 0.001). There was no evidence of heterogeneity. The lower risk of AF was found in cross-sectional and longitudinal studies and in studies stratified by average age (<60 or ≥60) and in cryptogenic stroke. Meta-regression by PFO detection technique suggested that studies using transoesophageal echocardiogram for PFO detection reported higher risk of AF (1.39, 95% confidence interval 1.14-1.70, p = 0.004). Conclusion: The presence of a PFO in patients with ischemic stroke/TIA may be associated with a lower risk of AF. Few studies have estimated the risk of future AF in patients with PFO.

Circulatory Stasis or Thrombus in Left Atrial Appendage, An Easy Diagnostic Solution

OBJECTIVE

The purpose of this study was to assess the diagnostic performance of prone position cardiac multidetector computed tomography (MDCT) in the detection of left atrial appendage (LAA) thrombi and to make differentiate between thrombus and circulatory stasis using transesophageal echocardiography (TEE) as the criterion-standard imaging modality.

METHODS

From December 2014 to April 2016, 53 consecutive patients were admitted to the hospital because of circulatory stasis or/and thrombus. All patients underwent prone-position MDCT and TEE. Prone-position MDCT and TEE sensitivity, specificity, positive predictive value, and negative predictive value were calculated.

RESULTS

For the MDCT scan in the prone position, the sensitivity, specificity, positive predictive value, and negative predictive value results were 100%, 100%, 100%, and 100%, respectively.

CONCLUSIONS

Multidetector computed tomography scanning in the prone position differentiates circulatory stasis and LAA thrombus, is clinically useful for detecting and ruling out LAA thrombus, and may be an alternative to TEE as a diagnostic tool.

Thromboembolic Complications Following Tissue Plasminogen Activator Therapy in Patients of Acute Ischemic Stroke - Case Report and Possibility for Detection of Cardiac Thrombi

Many reports focus on the probability of intracranial hemorrhage as a complication after recombinant tissue plasminogen activator (rt-PA) therapy. However, thromboembolic complications are not well discussed. We experienced a case in which severe thromboembolic complications occurred in the right radial and right ulnar artery. Arterial fibrillation was observed in this case. If multiple thrombi exist in the atrium or ventricle, multiple small embolic particles may appear following thrombolytic therapy, and that may be a potential risk of secondary thromboembolic complications due to incomplete dissolution of thrombi. Transesophageal echocardiography is a standard method to detect intracardiac sources of emboli in the case of arterial fibrillation. Transesophageal echocardiography is, however, an invasive method for patients with ischemic stroke during rt-PA therapy. High resolution enhanced CT could be a useful tool and may be a reliable alternative to transthoracic echocardiography. Careful assessment of thromboembolic complications following rt-PA therapy in patients with arterial fibrillation is needed. In this case report and mini review, we would like to discuss about the accurate diagnostic methods to detect cardiac or undetermined embolic sources and provide expedited stroke care. These embolic sources may be more readily discovered during rt-PA therapy within the limited therapeutic time window.

Predictive Value of Computed Tomography Angiography-Determined Occlusion Type in Stent Retriever Thrombectomy

BACKGROUND AND PURPOSE

We investigated whether occlusion type identified with computed tomography angiography (CTA-determined occlusion type) could predict endovascular treatment success using stent retriever (SR) thrombectomy.

METHODS

Consecutive patients with stroke who underwent CTA and then endovascular treatment for intracranial large artery occlusion were retrospectively reviewed. CTA-determined occlusion type was classified into truncal-type occlusion or branching-site occlusion and compared with digital subtraction angiography-determined occlusion type during endovascular treatment. Three rapidly- and readily-assessable pre-procedural findings (CTA-determined occlusion type, atrial fibrillation, and hyperdense artery sign), which may infer occlusion pathomechanism (embolic versus nonembolic) before endovascular treatment, were evaluated for association with SR success along with stroke risk factors and laboratory results. In addition, the predictive power of the 3 pre-procedural findings for SR success was compared with receiver operating characteristic curve analyses.

RESULTS

A total of 238 patients (mean age, 70.0 years; male patients, 52.9%) were included in this study. CTA-determined occlusion type corresponded adequately with digital subtraction angiography-determined occlusion type (P=0.453). Atrial fibrillation (odds ratio, 2.66; 95% confidence interval, 1.25-5.66) and CTA-determined branching-site occlusion (odds ratio, 8.20; confidence interval, 3.45-19.5) were independent predictors for SR success. For predicting SR success, the area under the receiver operating characteristic curve value for CTA-determined branching-site occlusion (0.695) was significantly greater than atrial fibrillation (0.594; P=0.038) and hyperdense artery sign (0.603; P=0.023).

CONCLUSIONS

CTA-determined branching-site occlusion was significantly associated with SR success. Furthermore, among the 3 rapidly- and readily-assessable pre-procedural findings, CTA-determined branching-site occlusion had the greatest predictive power for SR success.

Pre-stroke glycemic control is associated with early neurologic deterioration in acute atrial fibrillation-related ischemic stroke

Background

It has been suggested that AF-related ischemic stroke (IS) that is accompanied by atherosclerotic burden have poorer outcomes. The aim of this study was to investigate the importance of pre-stroke glycemic control (PSGC) on the early neurologic deterioration (END) of patients with acute AF-related IS.

Methods

We retrospectively recruited 121 patients with AF-related IS who also had Diabetes mellitus (DM). The HbA1C level was measured in all subjects. END was defined as an increase in the National Institute of Health Stroke Scale (NIHSS) score of 4 NIHSS points within 7 days of symptom onset compared to the initial NIHSS score.

Results

In this study, 20.7% (25 patients) were classified as having a poor PSGC status with a HbA1C level above 8.0%. In the univariate analysis, a poor PSGC status (p < 0.01), smoking (p = 0.01), severe neurologic deficits at admission (p = 0.01), and a larger size of ischemic lesions on DWI (p < 0.01) were associated with the occurrence of END. In the multivariate model, a poor PSGC status (p = 0.02) and larger size of ischemic lesions on MRI (p < 0.01) were independent predictors of END in acute AF-related IS.

Conclusion

The HbA1c level upon admission was independently associated with significant prediction of END in acute AF-related IS.

Stroke risk reduction outweighed bleeding risk increase from vitamin K antagonist treatment among nonvalvular atrial fibrillation patients with high stroke risk and low bleeding risk

OBJECTIVE

Warfarin is widely used for stroke prevention in patients with nonvalvular atrial fibrillation (NVAF). We compared the rates of stroke and major bleeding in NVAF patients with a high stroke risk and low bleeding risk profile during warfarin treated (W+) and warfarin untreated (W-) periods.

METHOD

Insurance claims from six commercial, Medicaid or Medicare databases were analyzed from 2000 to 2014. NVAF patients treated with warfarin, with a CHADS₂/CHA₂DS₂-VASc score ≥2, and an ATRIA score ≤3 at baseline were identified. Incidence rate ratios (IRRs) of stroke and major bleeding were calculated for W + versus W- episodes of person-time, as well as for first 30 days versus beyond 30 days of W + episodes.

RESULTS

Among 316,145 patients, anticoagulant prophylaxis with warfarin significantly reduced stroke risk, with IRRs ranging from 0.48 (95% CI: 0.46-0.51) to 0.80 (95% CI: 0.70-0.91), and increased major bleeding risk, with IRRs ranging from 1.13 (95% CI: 1.10-1.15) to 1.95 (95% CI: 1.10-3.45). Stroke and major bleeding rates were higher during the first 30 days of W + than beyond.

CONCLUSION

In NVAF patients at high risk for stroke and low risk for bleeding, our data confirm the effectiveness of anticoagulation for stroke prevention. The decrease in stroke risk of anticoagulation may outweigh the risk of major bleeding events, particularly among elderly patients. Potential risks of warfarin during initiation warrant attention, especially among patients who stop and start therapy repeatedly.

Embolic stroke and after-admission atrial fibrillation

BACKGROUND

Although atrial fibrillation (AF) is a leading cause of recurrent embolic stroke, secondary AF after stroke has been reported frequently. Because of the different treatment each uses, it is important to detect the exact stroke-etiology.

OBJECTIVES

The aim of this study was to compare the embolic stroke in patients with known AF and after-admission AF (AAAF).

METHODS

Between October 2002 and July 2009, those who were diagnosed with AF (n=354) were enrolled in our study out of a total of 2026 acute ischemic stroke (IS) patients. The embolic lesion patterns were assessed by two stroke specialists who were blinded to the clinical information.

RESULTS

Among 354 IS patients with AF, the number of patients with embolic stroke was 314. Patients with embolic stroke were younger and more likely to have larger left atrial (LA)/Aortic diameter ratio. Approximately 90.4% of those with known AF had embolic stroke, while <60% of patients with AAAF had embolic stroke. Nevertheless, anticoagulants were prescribed similarly in both groups at discharge. The LA/Aortic diameter ratio<1.5 was significantly related to AAAF. After adjusting for multiple co-variables, compared to the patients with known AF, patients with AAAF had reduced risk of embolic stroke (Odds ratio 0.11, 95% Confidence interval 0.03-0.36, p-value<0.001).

CONCLUSIONS

Compared to AAAF after stroke, known AF was associated with embolic stroke. Therefore, we suggest that stroke etiology and some novel echocardiographic indicators such as LA enlargement might be contemplated before routine using of anticoagulants in IS patients with AF.

Poor Outcome of Stroke Patients With Atrial Fibrillation in the Presence of Coexisting Spontaneous Echo Contrast

BACKGROUND AND PURPOSE

Spontaneous echo contrast (SEC) is frequently detected in patients with atrial fibrillation (AF). Coexisting SEC in patients with AF may be associated with heightened thrombogenicity, which affects stroke outcomes.

METHODS

Consecutive stroke patients with nonvalvular AF who underwent transesophageal echocardiography were included in this study. We compared initial stroke severity and functional outcome at 3 months between the patients with and those without SEC.

RESULTS

Of 440 patients with nonvalvular AF who underwent transesophageal echocardiography during a 7-year period, 193 (43.9%) patients had SEC. Stroke was more severe in the patients with SEC than in those without SEC (National Institute of Health Stroke Scale score: median [interquartile range], 5 [2-12] versus 3 [1-8]; P=0.004). The patients with SEC more frequently had poor functional outcomes (modified Rankin scale score of >2) at 3 months than those without SEC (32.3% versus 16.1%; P<0.001). On multivariate analysis, the presence of SEC was an independent factor of poor outcome (odds ratio, 2.09; 95% confidence interval, 1.24-3.53).

CONCLUSIONS

In the ischemic stroke patients with nonvalvular AF, coexisting SEC was associated with more severe stroke and was predictive of poor long-term functional outcome.

Management of tandem internal carotid and middle cerebral arterial occlusions with endovascular multimodal reperfusion therapy

The aim of this study was to evaluate the safety and efficacy of multimodal reperfusion therapy (MMRT) for tandem internal carotid artery and middle cerebral arterial (TIM) occlusions. Cases of TIM occlusion were collected and retrospectively reviewed. The analyzed objects included etiology, sites of tandem occlusion, collateral flow, location and size of infarcts. Combined with mechanical recanalization techniques and its complications, the National Institute of Health Stroke Scale (NIHSS) score and imaging data that was derived pre- and post-procedure were further contrasted. The study enrolled six patients with TIM occlusions. The mean NIHSS score on admission was 17 (range 13-20) and the median time from puncture to recanalization was 141 min (range 60-230). The substantial recanalization rate (Thrombolysis in Cerebral Infarction 2b or 3) was 83.3% and no symptomatic intracerebral hemorrhage was observed. The mean NIHSS score after three days was 14 (range 10-19) and 9 (range 3-17) following discharge. However, one patient died of pulmonary infection one month after discharge. For the five patients who survived, the modified Rankin Scale was evaluated at three months, with scores of 3, 1, 3, 5 and 3, respectively. It is concluded that endovascular therapy for acute TIM occlusions are complex, MMRT may be relatively safe and effective.

Acute embolic occlusion of the right common iliac artery after revision total hip arthroplasty treated with catheter-directed thrombolysis and balloon angioplasty: A case report

METHODS

A 63-year-old woman with atrial fibrillation presented clinical symptoms and signs of acute ischemia in the right lower extremity on the 17th postoperative day after revision total hip arthroplasty of the left hip for aseptic loosening of femoral component. Aspirin was discontinued 7 days before surgery. Both computed tomography angiography and digital subtraction angiography demonstrated complete occlusion of the right common iliac artery. An emergency catheter-directed thrombolysis with urokinase combined with balloon angioplasty was performed to obtain complete patency of the right common iliac artery.

RESULTS

The patient received anticoagulation and antiplatelet therapy postoperatively and was fine at the 2-year follow-up.

CONCLUSIONS

This case demonstrated that catheter-directed thrombolysis combined with balloon angioplasty could be an efficacious, minimally invasive approach for the treatment of acute embolic occlusion of the common iliac artery. Preoperative anticoagulation for patients undergoing total hip arthroplasty with long-term use of aspirin for atrial fibrillation needs further investigation.

Impact of Intracranial Atherosclerotic Stenosis on the Prognosis in Acute Ischemic Stroke Patients with Cardioembolic Source

BACKGROUND AND AIM

In recent days, intracranial atherosclerotic stenosis (IAS) has been reportedly related to recurrent stroke and mortality in the total patient population with ischemic stroke. However, its impact on the prognosis of the patients with cardioembolic source is not yet established. This study attempted to investigate whether IAS was associated with poor outcome in stroke patients with cardioembolic source.

METHODS

Overall, 223 patients with acute ischemic stroke and cardioembolic source were included in this study. IAS was defined as ≥ 50% stenosis on enhanced MRA, and cardioembolic sources were detected by ECG and echocardiography. Follow-up data were obtained from outpatient medical records and/or telephone interviews.

RESULTS

Overall, 60 major clinical events causing poor outcome occurred in 58 patients (26.0%). Patients with IAS had significantly higher rates of death and stroke recurrence than those without IAS (p = 0.015 and 0.046 each by log rank test). The multivariate Cox proportional hazards regression analysis showed that IAS was significantly related to the poor outcome (hazard ratio 1.725, 95% confidence interval 1.020-2.920, p = 0.042).

CONCLUSIONS

In acute ischemic stroke patients with cardioembolic source, IAS may be considered a marker of a high risk of stroke recurrence or death.

Factors associated with ischemic stroke on therapeutic anticoagulation in patients with nonvalvular atrial fibrillation

PURPOSE

In this study, we investigated the stroke mechanism and the factors associated with ischemic stroke in patients with nonvalvular atrial fibrillation (NVAF) who were on optimal oral anticoagulation with warfarin.

MATERIALS AND METHODS

This was a multicenter case-control study. The cases were consecutive patients with NVAF who developed cerebral infarction or transient ischemic attack (TIA) while on warfarin therapy with an international normalized ratio (INR) ≥2 between January 2007 and December 2011. The controls were patients with NVAF without ischemic stroke who were on warfarin therapy for more than 1 year with a mean INR ≥2 during the same time period. We also determined etiologic mechanisms of stroke in cases.

RESULTS

Among 3569 consecutive patients with cerebral infarction or TIA who had NVAF, 55 (1.5%) patients had INR ≥2 at admission. The most common stroke mechanism was cardioembolism (76.0%). Multivariate analysis demonstrated that smoking and history of previous ischemic stroke were independently associated with cases. High CHADS2 score (≥3) or CHA₂DS₂-VASc score (≥5), in particular, with previous ischemic stroke along with ≥1 point of other components of CHADS₂ score or ≥3 points of other components of CHA₂DS₂-VASc score was a significant predictor for development of ischemic stroke.

CONCLUSION

NVAF patients with high CHADS₂/CHA₂DS₂-VASc scores and a previous ischemic stroke or smoking history are at high risk of stroke despite optimal warfarin treatment. Some other measures to reduce the risk of stroke would be necessary in those specific groups of patients.

Adenosine diphosphate-induced platelet aggregation might contribute to poor outcomes in atrial fibrillation-related ischemic stroke

Systemic atherosclerosis is involved in ischemic damages and cardioembolism after atrial fibrillation (AF)-related ischemic stroke (IS). Platelet activation is a critical factor in systemic atherosclerosis; however, there is little information regarding the role of platelet activation on the outcome of AF-related IS. We investigated the relationship between adenosine diphosphate (ADP)-induced platelet aggregation and the long-term outcomes of AF-related IS. We studied 249 patients who were exclusively treated with anticoagulation therapy after they had experienced AF-related IS. We evaluated their platelet function 5 days after admission to the hospital by using an optic platelet aggregometer test. We also assessed the prognoses of patients 90 days after the AF-related IS. Our results showed that ADP-induced platelet aggregation was positively correlated with CHA2DS2-VASc scores (r = .285, P < .01). Totally, 107 (43.0%) patients had a poor outcome at 90 days after IS. Univariate analysis showed that the following factors significantly contribute to a poor outcome: older age (odds ratio [OR] = 1.07, confidence interval [CI] 1.04-1.10, P < .01), a history of stroke (OR = 3.24, CI 1.61-6.53, P < .01), high scores on the National Institutes of Health Stroke Scale (NIHSS; OR = 1.25, CI 1.18-1.32, P < .01), increased white blood cell counts (OR = 1.12, CI 1.02-1.24, P < .01), high CHA2DS2-VASc scores (≥5, OR = 7.31, CI 3.36-15.93, P = .025), and the highest tertile of ADP-induced platelet aggregation (≥72%, OR = 3.17, CI 1.67-5.99, P < .01). Of these factors, high NIHSS scores (OR = 1.27, CI 1.20-1.36, P < .01), high CHA2DS2-VASc scores (OR = 4.69, CI 1.21-18.14, P = .03), and the highest tertile of ADP-induced platelet aggregation (OR = 2.49, CI 1.17-5.27, P = .02) were independently associated with a poor outcome at 90 days after IS. Therefore, our results suggest that platelet activation might affect the outcome of AF-related IS.

Practical Issues to Prevent Stroke Associated with Non-valvular Atrial Fibrillation

Stroke associated with non-valvular atrial fibrillation (NVAF) is one of the most important subtypes of ischemic stroke, and its importance is becoming even more apparent in an aging population. To assess the risk of stroke associated with NVAF, the CHADS2 and CHA2DS2-VASc scores are mainly used. Such scores can be used to predict the recurrence and prognosis of ischemic stroke. In addition, new oral anticoagulants (NOACs) and devices are being evaluated in the prevention of stroke associated with NVAF in addition to treatment with the conventional oral anticoagulant, warfarin. Since clinical experience with NOACs is not globally sufficient, a cautious approach is needed.

Computed tomography for detecting left atrial thrombus: a meta-analysis

INTRODUCTION

Thromboembolism, usually originating from the left atrium (LA) and left atrial appendage (LAA), is a major complication of atrial fibrillation and may result in transient ischemic attack and stroke. Computed tomography (CT) is a noninvasive test for detection of LA and LAA thrombus. We sought to conduct a meta-analysis to evaluate the accuracy of CT in detecting LA/LAA thrombus.

MATERIAL AND METHODS

The PubMed, Medline, ISI Web of Knowledge and Cochrane Library databases up to June 2012 were searched for studies comparing CT and transesophageal echocardiography as the reference standard in detecting LA/LAA thrombus. Meta-analysis methods were used to pool sensitivity and specificity and to construct summary receiver operating characteristic (SROC) curves.

RESULTS

A total of 9 studies with 1646 patients were included in this meta-analysis. The publication years spanned from 2007 to 2012. For CT diagnosis of LA/LAA thrombus, the mean sensitivity and specificity were 81% (95% CI: 70-90%) and 90% (95% CI: 88-91%), respectively. The SROC analysis showed an area under the curve of 0.93.

CONCLUSIONS

Computed tomography shows a good diagnostic accuracy in detecting LA/LAA thrombus with high sensitivity and specificity. Thus CT should be considered the foremost noninvasive alternative to transesophageal echocardiography for detecting LA/LAA thrombus. Randomized studies at the patient level are needed to address the potential use of CT in detecting LA/LAA thrombus.

Long-term mortality in patients with stroke of undetermined etiology

BACKGROUND AND PURPOSE

The determination of stroke etiology is essential for planning treatment for stroke prevention. However, the etiology of stroke is undetermined in many patients.

METHODS

During a 10-year period, consecutive patients with acute ischemic stroke were enrolled. The stroke etiology was determined based on the Trial of ORG 10172 in Acute Stroke Treatment classification. Long-term mortality and causes of death were identified using death certificates. The standardized mortality ratio was calculated to compare the mortality in patients with stroke and that in the general Korean population.

RESULTS

In total, 3278 patients were enrolled and followed-up for a median of 3.4 years (interquartile range, 1.5-5.7). The stroke subtype was undetermined in 37% because of negative evaluation (21.2%), multiple causes (10.6%), and incomplete evaluation (4.8%). Poor functional outcome at 3 months (modified Rankin scale score >2) was more frequent in patients with an incomplete evaluation than in those with the other stroke subtypes (49.6% vs 24.5%; P<0.001). During follow-up, 781 patients (23.8%) died. The overall cumulative death rate was highest in patients with an incomplete evaluation (12.7% within 30 days, 25.5% within 1 year, and 35.7% within 3 years), followed by those with cardioembolism. Multivariate analysis after adjusting for covariates including initial stroke severity, the mortality of patients with an incomplete evaluation was second lowest after cardioembolism, whereas that in patients with a negative evaluation was low.

CONCLUSIONS

Long-term mortality in patients with an incomplete evaluation was quite high. Etiologic work-up helps to better define the stroke subtype and determine the prognosis.

Identifying a high stroke risk subgroup in individuals with heart failure

BACKGROUND

Heart failure (HF) is associated with an overall stroke rate that is too low to justify anticoagulation in all patients. This study was conducted to determine if vascular risk factors can identify a subgroup of individuals with heart failure with a stroke rate high enough to warrant anticoagulation.

METHODS

The REGARDS study is a population-based cohort of US adults aged ≥45 years. Participants are contacted every 6 months by telephone for self- or proxy-reported stroke and medical records are retrieved and adjudicated by physicians. Participants were characterized into 3 groups: HF without atrial fibrillation (AF), AF with or without HF, and neither HF nor AF. Cardiovascular risk factors at baseline were compared between participants with and without incident stroke in HF and AF. Stroke incidence was assessed in risk factor subgroups in HF participants.

RESULTS

Of the 30,239 participants, those with missing/anomalous data were excluded. Of the remaining 28,832, 1360 (5%) had HF without AF, 2528 (9%) had AF, and 24,944 (86%) had neither. Previous stroke/transient ischemic attack (TIA; P = .0004), diabetes mellitus (DM; P = .03), and higher systolic blood pressure (P = .046) were associated with increased stroke risk in participants with HF without AF. In participants with HF without AF, stroke incidence was highest in those with previous stroke/TIA and DM (2.4 [1.1, 4.0] per 100 person-years).

CONCLUSIONS

The combination of previous stroke/TIA and DM increases the incidence of stroke in participants with HF without AF. No analyzed subgroup had a stroke rate high enough to make it likely that the benefits of warfarin would outweigh the risks.

Determinants of infarction patterns in cardioembolic stroke

BACKGROUND

Embolic infarctions from the heart are known to cause multiple scattered infarct lesions as well as single, large territorial infarctions. However, it remains unknown which factors contribute to these different infarction patterns in patients with potential cardiac sources of embolism (PCSE).

METHODS

We examined 388 ischemic stroke patients with a high-risk PCSE using diffusion-weighted imaging. Infarction patterns were categorized into a single large lesion, a single small lesion, confluent and additional lesions, or small scattered lesions. The relationships between infarction patterns and clinical and hematologic parameters were investigated.

RESULTS

Of the 388 patients, a single large lesion was detected in 139 (35.8%), a single small lesion in 29 (7.5%), confluent and additional lesions in 171 (44.1%), and small scattered lesions in 49 (12.7%). Prior use of antiplatelet agents and anticoagulant were associated with the pattern of small scattered lesions and a single small lesion, respectively. Additionally, higher white blood cell counts were associated with confluent and additional lesions. The type of high-risk PCSE was not related to a specific infarction pattern.

CONCLUSIONS

These results suggest that platelet function and inflammatory processes may directly affect the thrombus formation in the cardiac chamber.

Recent Advances in Percutaneous Cardioscopy

Percutaneous cardioscopy, using high-resolution fiberoptic imaging, enables direct visualization of the cardiac interior, thereby enabling macroscopic pathological diagnosis. Percutaneous cardioscopy has demonstrated that the endocardial surface exhibits various colors characteristic of different heart diseases. This imaging modality can now be used for evaluation of the severity of myocardial ischemia, and staging of myocarditis. Myocardial blood flow recovery induced by vasodilating agents or percutaneous coronary interventions can be clearly visualized. Morphological and functional changes in the cardiac valves can also be evaluated. Cardioscope-guided endomyocardial biopsy enables pin-point biopsy of the diseased myocardium. Recently, dye-image cardioscopy and fluorescence cardioscopy were developed for evaluation of the subendocardial microcirculation. Cardioscope-guided intracardiac therapies such as myotomy, myectomy, valvulotomy, and transendocardial angiogenic and myogenic therapy have been trialed using animal models in anticipation of future clinical applications. Percutaneous cardioscopy has the potential to contribute to our understanding of heart disease, and to assist in guidance for intracardiac therapies.

Cardioscopic detection of left ventricular thrombi. -With special reference to a comparison with left ventriculography and echocardiography-

BACKGROUND

Thrombosis occurs in the left ventricle and causes ischemic cerebral attacks. However, differences in the incidence of left ventricular thrombi (LVT) among various categories of heart diseases are not known.

METHODS AND RESULTS

From April 2000 to 31 March 2008, 258 patients (104 females and 154 males; age 63 ± 6 years) with a heart disease underwent cardioscopy of the left ventricle. LVT were detected by cardioscopy in 78 of 258 patients; 12.5% of 57 patients with stable angina, 0% of 9 with unstable angina, 45.2% of 42 with acute myocardial infarction, 23.2% of 43 with old myocardial infarction, 61.9% of 21 with idiopathic acute myocarditis, 44.3% of 68 with idiopathic chronic myocarditis, 33.3% of 6 with rheumatic valvular disease, 25.7% of 31 with idiopathic dilated cardiomyopathy and in 8.0% of 12 with idiopathic hypertrophic cardiomyopathy. Nine of 78 thrombi were globular and 69 were mural. The detection rate of LVT by cardioscopy, left venticulography, non-contrast and contrast echocardiography was 30.2%, 2.7%, 1.9% and 7.0%, respectively.

CONCLUSIONS

LVT were frequently detected by cardioscopy in patients with heart diseases. Although invasive, cardioscopy was more sensitive in detecting LVT than left ventriculography, and non-contrast and contrast echocardiography.

Failure of complete recanalization is associated with poor outcome after cardioembolic stroke

BACKGROUND

  Recanalization is strongly associated with outcomes after thrombolytic treatment. Cardiac emboli are known as better response to fibrinolytic agents because they are fibrin-rich; however, cardioembolic stroke itself is associated with poor outcomes and high mortality. Completeness of recanalization may therefore affect the outcome of cardioembolic stroke. We investigated whether degree of recanalization influences outcomes following fibrinolytic therapy in cardioembolic stroke.

METHODS

  Consecutive stroke patients with relevant artery occlusions on baseline CT angiography who had received thrombolytic treatment were enrolled. Completeness of recanalization was assessed by the Thrombolysis in Myocardial Infarction (TIMI) grade, which was compared between patients with and without cardiac sources of embolism (CSE). We also investigated independent predictors of poor outcome (modified Rankin scale score 3-6) at 3 months.

RESULTS

  Of the 127 patients enrolled, 65 (51%) had one or more CSE. Although the overall recanalization rates (TIMI 2 or 3) in patients with CSE (65%) and patients without CSE (68%) were similar (P=0.710), patients with CSE were less likely to show complete recanalization (TIMI 3) compared with those without CSE (19% vs. 39%, P=0.011). Multivariate analysis revealed that CSE was associated with failure of complete recanalization (OR 2.809, 95% CI 1.097-7.192) and was an independent predictor of poor outcome at 3months (OR 3.629, 95% CI 1.205-8.869).

CONCLUSIONS

  In cardioembolic strokes, failure of complete recanalization following thrombolytic therapy was frequent and was associated with poor outcome after thrombolysis.

Stroke severity in concomitant cardiac sources of embolism in patients with atrial fibrillation

BACKGROUND

Atrial fibrillation (AF), which is the most common etiology of cardioembolic stroke, may be accompanied by other cardiac sources of embolism. The heterogeneity and multiplicity of the cardiac sources of embolism may influence stroke severity via formation of thrombi with heterogenous compositions, ages, and sizes. We investigated among stroke patients with AF whether stroke severity is different between patients with concomitant potential cardiac sources of embolism and those without.

METHODS

The subjects for this study were consecutive patients with cerebral infarction and AF who underwent transesophageal echocardiography during a 10-year period. The definitions and determination of high- and medium-risk potential cardiac sources of embolism were based on the Trial of Org 10172 in Acute Stroke Treatment classification. Initial stroke severity and infarct sizes were compared between patients with concomitant potential cardiac sources of embolism and those without.

RESULTS

Of the 266 patients enrolled, 181 (68.0%) had one or more concomitant potential cardiac sources of embolism. Left atrial thrombus and spontaneous echo contrast were most common. Patients with concomitant potential cardiac sources of embolism had a higher median score on the initial National Institute of Health Stroke Scale (6 vs. 3, p=0.005) and a larger infarction diameter (45.4±31.3 mm vs. 35.5±26.6 mm, p=0.002) than those without. Occlusion of the symptomatic arteries was more frequently detected in patients with concomitant potential cardiac sources of embolism.

CONCLUSIONS

Stroke patients with AF frequently had concomitant potential cardiac sources of embolism, and strokes were more severe in them.

Increasing frequency and burden of cerebral artery atherosclerosis in Korean stroke patients

PURPOSE

Koreans have been undergoing rapid lifestyle changes that may have an effect on patterns of cerebral artery atherosclerosis. This study was aimed at determining the frequency and distribution of atherosclerosis in the cerebral arteries and associated temporal changes over the past eight-year period among Korean stroke patients.

MATERIALS AND METHODS

By using stroke registry data registered between April 1999 and March 2007, we investigated the presence, severity, and location of cerebral artery atherosclerosis as determined by angiographic findings. Their annual patterns and association with vascular risk factors were investigated.

RESULTS

Of 1,955 patients, 1,517 patients (77.6%) demonstrated atherosclerosis in one or more arteries. A significantly increasing trend of atherosclerosis was observed during the past eight years, which was ascribed to an increase of combined extracranial (EC) and intracranial (IC) atherosclerosis. The number of atherosclerotic arteries increased as the number of risk factors increased. In the multivariate analysis, the year and vascular risk factors were independent predictors of the presence of atherosclerosis.

CONCLUSION

We found that the atherosclerotic burden has been increasing for the past eight years in Korean stroke patients, particularly the combined EC and IC subtype. Lifestyle changes and increase in vascular risk factors may be contributing factors.

Blood pressure and stroke in heart failure in the REasons for Geographic And Racial Differences in Stroke (REGARDS) study

BACKGROUND AND PURPOSE

The prevalence of stroke is increased in individuals with heart failure (HF). The stroke mechanism in HF may be cardiogenic embolism or cerebral hypoperfusion. Stroke risk increases with decreasing ejection fraction and low cardiac output is associated with hypotension and poor survival. We examine the relationship among blood pressure level, history of stroke/transient ischemic attack (TIA), and HF.

METHODS

We compared the prevalence of self-reported history of stroke or TIA in the REasons for Geographic And Racial Differences in Stroke (REGARDS) participants with HF (as defined by current digoxin use) and without HF. We excluded participants with atrial fibrillation or missing data. We examined the relationship between HF and history of stroke/TIA within tertiles of systolic blood pressure (SBP) adjusting for patient demographic and health characteristics.

RESULTS

Prevalent stroke/TIA were reported by 66 (26.3%) of 251 participants with and 1805 (8.5%) of 21 202 participants without HF (P<0.0001). Within each tertile of SBP, the unadjusted OR (95% CI) for prior stroke/TIA among those with HF compared with those without HF (the reference group) was, 4.0 (2.8 to 5.8) for SBP <119.5 mm Hg, 2.7 (1.8 to 3.9) for SBP >or=119.5 but <131.5 mm Hg, and 2.3 (1.6 to 3.2) for SBP >or=131.5 mm Hg. After adjustment, the relationship between prior stroke/TIA and HF remained significant only within the lowest tertile of SBP (<119.5 mm Hg; 3.0; 1.5 to 6.1).

CONCLUSIONS

The odds of prevalent self-reported stroke/TIA are increased in participants with HF and most markedly increased in participants with low SBP. Longitudinal data are needed to determine whether this reflects stroke/TIA secondary to thromboembolism from poor cardiac function or secondary to cerebral hypoperfusion.

Comparison of the characteristics for in-hospital and out-of-hospital ischaemic strokes

BACKGROUND AND PURPOSE

Patients who are being admitted to a hospital due to diseases other than stroke may develop a stroke (in-hospital stroke; IHS).

METHODS

We enrolled 111 consecutive patients who developed IHS outside a neurology ward during a 5-year period at a single hospital. The frequency, characteristics, and outcomes for IHS patients were compared with patients who develop ischaemic stroke outside of the hospital (out-of-hospital stroke; OHS).

RESULTS

Forty-six percent of IHS occurred in the department of cardiology or cardiovascular surgery and 60% were associated with surgery or procedures. In comparison with the OHS patient group, the IHS patient group showed an increased frequency of cardiac disease, leukocytosis, and anemia. Cardioembolism, stroke of other determined etiologies, and an incomplete evaluation were more common in the IHS group, whereas large artery atherosclerosis was more frequent in the OHS group. The IHS group had up to a 10-fold higher mortality than the OHS group, with sepsis being the most common cause of death in the IHS group.

CONCLUSIONS

IHS has distinct etiologies and stroke mechanisms from OHS. The prevention and management of infection could decrease mortality in IHS patients.