Differential patterns of evolution in acute middle cerebral artery infarction with perfusion-diffusion mismatch: atherosclerotic vs. cardioembolic occlusion

Endovascular Treatment for Acute Large Vessel Occlusion Due to Underlying Intracranial Atherosclerotic Disease

Intracranial atherosclerotic disease (ICAD) is one of the most common causes of acute ischemic stroke worldwide. Patients with acute large vessel occlusion due to underlying ICAD (ICAD-LVO) often do not achieve successful recanalization when undergoing mechanical thrombectomy (MT) alone, requiring rescue treatment, including intra-arterial thrombolysis, balloon angioplasty, and stenting. Therefore, early detection of ICAD-LVO before the procedure is important to enable physicians to select the optimal treatment strategy for ICAD-LVO to improve clinical outcomes. Early diagnosis of ICAD-LVO is challenging in the absence of consensus diagnostic criteria on noninvasive imaging and early digital subtraction angiography. In this review, we summarize the clinical and diagnostic criteria, prediction of ICAD-LVO prior to the procedure, and EVT strategy of ICAD-LVO and provide recommendations according to the current literature.

Interobserver Agreement in Scoring Angiographic Results of Basilar Artery Occlusion Stroke Therapy

BACKGROUND AND PURPOSE

The modified TICI Infarction grading system is a metric currently used to evaluate angiographic results of thrombectomy for large-vessel occlusion in ischemic stroke. Originally designed for evaluating MCA territories, it is currently used for other vessel occlusions, including the posterior circulation. We postulate that the modified TICI use for the posterior circulation is not accurate due to the different vascular territories supplied by vertebrobasilar vasculature, making grading more complex.

MATERIALS AND METHODS

We collected angiographic results from 30 patients who presented with acute posterior circulation occlusions between 2015 and 2018 and underwent thrombectomy in our institution. Eight observers were asked to evaluate the TICI scores before and after thrombectomy. The multirater statistics were computed using Fleiss κ analysis. Further data were collected regarding the potential brain territories at risk and the existence of atherosclerotic disease in the basilar artery.

RESULTS

The overall agreement κ reached 0.277 (SD, 0.013), which suggests a "fair" agreement among the raters. On average, 45% of observers achieved a high accuracy in predicting brain areas at risk of ischemia. As for the existence of basilar atherosclerotic disease, a high agreement (defined as at least 5 of 6 observers) was seen in 20 of the 30 patients.

CONCLUSIONS

Despite TICI being ubiquitous in stroke diagnostics, the high variability of posterior circulation TICI scores calls into question its use in these strokes. Other methods should be developed to assess recanalization in the posterior circulation.

FM Combined With NIHSS Score Contributes to Early AIS Diagnosis and Differential Diagnosis of Cardiogenic and Non-Cardiogenic AIS

A growing researchers have suggested that fibrin monomer (FM) plays an important role in early diagnosis of thrombotic diseases. We explored the application of FM in the diagnosis and classification of acute ischemic stroke (AIS). The differences in FM, D-dimer, and NIHSS scores between different TOAST (Trial of ORG 10172 in Acute Stroke Treatment) types were analyzed with one-way ANOVA; the correlation between FM, D-dimer and NIHSS score in patients with different TOAST classification was analyzed by Pearson linear correlation. The ROC curve was utilized to analyze the diagnostic performance. 1. FM was more effective in diagnosing patients with AIS than D-dimer. 2. The FM level in cardiogenic AIS was significantly different from that in non-cardiogenic patients (P < 0.05); the NIHSS score in cardiogenic stroke was significantly higher than in atherosclerotic and unexplained stroke group. Whereas, no statistical difference was observed in the D-dimer level between these groups (P > 0.05). 3. The correlation between FM and NIHSS scores in the cardiogenic (r = 0.3832) and atherosclerotic (r = 0.3144) groups was statistically significant. 4. FM exhibited the highest diagnostic efficacy for cardiogenic AIS; furthermore, FM combined with the NIHSS score was more conducive to the differential diagnosis of cardiogenic and non-cardiogenic AIS. FM detection contributes to the early diagnosis of AIS, and is important for the differential diagnosis of different TOAST types of AIS. Moreover, FM combined with the NIHSS score is valuable in the differential diagnosis of cardiogenic and non-cardiogenic AIS.

Antegrade Blood Flow on 4-Dimensional Computed Tomography Angiography Predict Stroke Subtype in Patients With Acute Large Artery Occlusion

Background

The purpose of this study was to determine whether the presence of antegrade blood flow was related to stroke subtype in patients with acute intracranial large artery occlusion.

Methods and Results

The prospectively collected data for consecutive patients who had occlusion of the unilateral M1 segment of the middle cerebral artery with or without internal carotid artery and received reperfusion therapy were retrospectively reviewed. Stroke causes were determined according to the Trial of ORG 10172 in Acute Stroke Treatment standard. We defined antegrade flow as early opacification at the distal interface of the clot with subsequent distal extension on 4‐dimensional computed tomography angiography. A total of 387 large artery occlusion patients were analyzed (229 men and 158 women; mean age, 71±14 years), including 77 (19.9%) with large artery atherosclerosis (LAA), 206 (53.2%) with cardioembolism, and 104 (26.9%) with undetermined causes. Antegrade flow was found in 206 (53.2%) patients, and 181 (46.8%) presented with retrograde flow. The rate of antegrade flow was much higher in patients with LAA than in those with cardioembolism (85.7% versus 42.2%, P<0.001). Multivariable logistic regression revealed that presence of antegrade flow was significantly associated with cuse of LAA after adjusting for confounding factors, when setting cardioembolism as reference (odds ratio, 5.650; 95% confidence interval, 2.451–13.158; P<0.001). The sensitivity, specificity, and positive and negative predictive values of the antegrade flow for predicting LAA were 43.1%, 91.5%, 85.7%, and 57.8%, respectively.

Conclusions

Using 4‐dimensional computed tomography angiography, antegrade flow can be identified in more than half of acute anterior large artery occlusion patients and occurs more frequently in those with LAA as the cause of stroke.

Current knowledge of large vascular occlusion due to intracranial atherosclerosis: focusing on early diagnosis

Intracranial atherosclerosis (ICAS)-related large vascular occlusion (LVO) was an intractable subtype of acute ischemic stroke (AIS), which always needed rescue angioplasty and stenting and complicated the procedure of endovascular recanalization. Diagnosing ICAS-LVO accurately and early was helpful for both clinical treatment and trials. Digital subtraction angiography (DSA) was unable to provide an early and rapid diagnosis of ICAS-LVO based on current studies. A variety of pre-DSA methods had been used to distinguish ICAS-LVO with other subtypes of ischemic stroke, such as medical histories, clinical presentations, computed tomography or angiography (CT/CTA), and magnetic resonance imaging (MRI/MRA). This article briefly reviewed the status quo of the diagnosis and treatment of ICAS-LVO and summarized early diagnostic methods of ICAS-LVO from different aspects.

Effect of direct angioplasty therapy on acute middle cerebral artery occlusion with good leptomeningeal collateral

OBJECTIVE

The objective of this study was to investigate and discuss the effect of direct angioplasty therapy on acute middle cerebral artery occlusion (MCAO) patients with good leptomeningeal collateral circulation in 4.5 h.

PATIENTS AND METHODS

We retrospectively reviewed our acute ischemic stroke database from January 2017 to January 2019, then selected consecutive patients with evidence of the proximal M1 segments of MCAO and good leptomeningeal collateral who have received angioplasty or mechanical thrombectomy (MT). The baseline characteristics and outcome of patients was statistical analysis, included age, gender and risk factors, baseline national institutes of health stroke scale (NIHSS) scores, preoperative alberta stroke programme early CT (ASPECT) score, time from door to needle, time of door to puncture, endovascular procedure time, 7d NIHSS score and the modified treatment in cerebral infarction (m-TICI) 2b or 3, symptomatic hemorrhage, average hospital stays, modified rankin scale (mRS) score 0-2 at 3-month and mortality. All the thrombi were analyzed by histopathology. All statistical analysis was done with t-test for continuous data and χ2 test for binary data.

RESULTS

A total of 93 patients were included (direct angioplasty = 41 (44.1 %), MT = 52 (55.9 %)). There was no significant difference in baseline data between the two groups. The difference in the time of door to recanalization, the time of puncture to recanalization, symptomatic hemorrhage, and average hospital stays were significantly different between groups (P < 0.05). The other agents were not significantly different between groups (P > 0.05 each). Histopathological analysis showed all thrombi contained different amounts of platelets, fibrinogen, white blood cell, and red blood cell.

CONCLUSION

Direct angioplasty therapy on acute MCAO with good leptomeningeal collateral may help to shorten the time of surgery, reduce symptomatic hemorrhage, and hospital stay.

Recanalisation therapy in patients with acute ischaemic stroke caused by large artery occlusion: choice of therapeutic strategy according to underlying aetiological mechanism?

Various mechanisms underlie causative large artery occlusion (LAO) in patients with acute ischaemic stroke. Cardioembolic and atherosclerotic occlusions are the two most common types. The pathophysiological changes and responses to mechanical thrombectomy (MT) and antithrombotic treatments including thrombolysis, antiplatelet and anticoagulation therapy may vary among patients with different aetiological mechanisms of occlusion. Atherosclerotic occlusion is inclined to have relatively abundant collaterals and larger area of penumbra, hence a relatively wider time window for reperfusion therapy, while poor response to medical thrombolysis and MT. Severe residual stenosis and reocclusion occurred frequently after MT in atherosclerotic LAO. Angioplasty and stenting as rescue or the first-line therapy and more intensified antiplatelet therapy beyond related recommendations in the current guidelines are sometimes used in managing acute causative LAO because of poor recanalisation after recommended standard thrombolysis or MT therapy, which are usually based on individual experience. Standard protocol to establish emergent aetiological diagnosis of causative LAO and individualised aetiology-specific treatment strategy is needed.

Early Magnetic Resonance Imaging Predicts Early Neurological Deterioration in Acute Middle Cerebral Artery Minor Stroke

BACKGROUND

Early neurological deterioration (END) is an important factor associated with worse clinical outcome in minor strokes. Early magnetic resonance imaging (MRI) findings can provide better sensitivity to delineate stroke pathophysiology and have diagnostic value associated with causative mechanisms. The aim of this study was to investigate the relationship between early MRI finding and the presence of END in minor stroke patients with lesions in the middle cerebral artery (MCA) territory.

METHODS

Consecutive MCA minor stroke patients who were admitted to our center within 24 hours of symptom onset were included in this study. All patients underwent MRI within 24 hours of admission. We analyzed baseline characteristics, infarction patterns, and treatment algorithms. The correlation between early MRI findings and END, defined as National Institutes of Health Stroke Scale score increasing more than 2 points during 72 hours after admission, was also determined.

RESULTS

Across 211 patients meeting entry criteria between January 2010 and December 2013, internal border-zone (IBZ) infarcts on early MRI scan were observed in 23 of 65 patients with END (35.4%) and in 18 of 146 patients without END (12.3%, P < .001). Patients with IBZ infarcts were found to have more hyperlipidemia, less perforating artery infarcts, more pial artery infarcts, more cortical border-zone infarcts and more ipsilateral large arterial stenosis. Logistic regression analysis revealed that IBZ infarct was independently associated with END after adjustment for other factors (odds ratio, 2.50; 95% confidence interval, 1.09-5.74; P = .031).

CONCLUSIONS

Early MRI patterns of IBZ infarction are associated with END in minor stroke patients with acute infarcts of the MCA territory.

(18)F-fluoromisonidazole (FMISO) Positron Emission Tomography (PET) Predicts Early Infarct Growth in Patients with Acute Ischemic Stroke

BACKGROUND AND PURPOSE

(18) F-fluoromisonidazole (FMISO) positron emission tomography (PET) is used to image metabolically compromised but viable hypoxic tissue. We hypothesized that FMISO PET might predict early infarct growth in acute ischemic stroke patients with perfusion-diffusion mismatch in magnetic resonance imaging (MRI).

METHODS

We prospectively enrolled acute ischemic stroke patients who visited the emergency room within 48 hours after stroke onset and had perfusion-diffusion mismatch (>20%), as shown MRI. Infarct growth was defined as >20% increase of initial infarct volume or >5 mL in follow-up diffusion-weighted image 5 ± 2 days after stroke. The association between FMISO uptake and infarct growth was explored.

RESULTS

Of 19 enrolled patients, 10 (52.6%) showed increased FMISO uptake, with 8 of the latter showing infarct growth. None of the 9 patients who did not show FMISO uptake had infarct growth. FMISO uptake was significantly associated with infarct growth (Fisher's exact test; P < .01). FMISO PET scan had a sensitivity of 100% and a specificity of 82% (AUC = .909) in predicting infarct growth.

CONCLUSIONS

FMISO PET scan can predict early infarct growth in acute ischemic stroke patients with perfusion-diffusion mismatch in MRI.

Prediction of infarct growth and neurologic deterioration in patients with positive perfusion-diffusion mismatch

BACKGROUND

To assess the value of baseline clinical severity and perfusion-diffusion mismatch as predictors for further infarct growth and clinical outcome.

METHODS

Patients with acute ischemic stroke and initial perfusion-diffusion mismatch within 72 h were enrolled. Baseline perfusion defects on time-to-peak (TTP) and cerebral blood volume (CBV) maps were measured. Infarct volume and stroke severity were assessed by diffusion-weighted image (DWI) and NIHSS, and were repeatedly assessed 7 days later. The predictive value of baseline NIHSS and perfusion defects on further infarct growth and neurologic deterioration was determined.

RESULTS

Fifty-two patients (mean age 68.3±12.8 years, 42% women) were enrolled. CBV defects were significantly associated with infarct growth (CBV, p=0.02). Initial stroke severity, but not TTP and CBV mismatch (p=0.65 and 0.76, respectively), significantly inversely correlated with neurologic deterioration (p=0.001).

CONCLUSIONS

In patients with mismatch, those with severe symptoms initially are more likely to have infarct growth, while those with minor symptoms tend to suffer from larger extent of neurologic deterioration within 1 week. CBV is associated with further infarct growth but not clinical deterioration.

[Mechanical recanalization]

Although several studies and registries have focused on new interventional systems for the treatment of acute ischemic stroke, a standard procedure has not yet been established. The procedure itself is still controversially discussed but studies have shown that patients who were successfully treated with mechanical recanalization had a better clinical outcome.