Risk for symptomatic intracerebral hemorrhage after thrombolysis assessed by diffusion-weighted magnetic resonance imaging

The e-STROKE Study: The Design of a Prospective Observational Multicentral Study

Introduction: The e-STROKE study is a prospective, multicenter observational study designed to assess the impact of various CT parameters (including e-ASPECT, CT perfusion (CTP), collateral flow status, and the size and location of the ischemic lesion) on the clinical outcomes of patients with ischemic stroke, as evaluated by the modified Rankins Scale (mRS) three months post-stroke. This study also aims to investigate whether the use of multimodal CT imaging increases the number of patients eligible for recanalization therapy. The analysis will integrate data from the RES-Q registry and radiological data from the e-STROKE system provided by Brainomix Ltd. Aims: The primary aim is to determine the predictive value of CT parameters (e-ASPECTS, CTP, collateral vessel status, and ischemic lesion volume and location) on three-month functional outcomes, as defined by the mRS, in patients with non-lacunar stroke following recanalization treatment (IVT and/or MT). The secondary aim is to evaluate whether multimodal CT examination leads to an increase in the number of patients eligible for recanalization therapy. Additionally, this study seeks to assess the specificity and sensitivity of multimodal CT in distinguishing stroke mimics from actual strokes. Methods: This multicenter observational study involves patients with suspected acute ischemic stroke and a premorbid mRS ≤ 4, who are treated with endovascular thrombectomy (EVT), intravenous thrombolysis (IVT), or managed conservatively in stroke centers within the Czech Stroke Research Network (STROCZECH), which is part of the Czech Clinical Research Infrastructure Network (CZECRIN). Data collection includes demographic, clinical, and imaging data variables such as age, sex, ethnicity, risk factors, treatment times (OTT, DNT, and OGT), TICI scores, post-treatment hemorrhage (ECAS II), mRS outcome, stroke etiology, e-ASPECTS, acute ischemic volume (AIV), thrombus length on NCCT, CTA collateral score and collateral vessel density, location of large vessel occlusion, ischemic core, hypoperfusion volume, mismatch ratio and volume, final infarct volume, hemorrhage volume, and MRI in case of negative follow-up NCCT. Conclusions: We anticipate collecting robust clinical and radiological data from approximately 2000 patients across 22 centers over a 12-month period. The results are expected to enhance the precision of diagnostic and prognostic radiological markers in managing acute stroke.

Intravenous Thrombolysis in Posterior versus Anterior Circulation Stroke: Clinical Outcome Differs Only in Patients with Large Vessel Occlusion

The safety and efficacy of intravenous thrombolysis (IVT) are well established in anterior circulation stroke (ACS) but are much less clear for posterior circulation stroke (PCS). The aim of this study was to evaluate the occurrence of parenchymal hematoma (PH) and 3-month clinical outcomes after IVT in PCS and ACS. In an observational, cohort multicenter study, we analyzed data from ischemic stroke patients treated with IVT prospectively collected in the SITS (Safe Implementation of Treatments in Stroke) registry in the Czech Republic between 2004 and 2018. Out of 10,211 patients, 1166 (11.4%) had PCS, and 9045 (88.6%) ACS. PH was less frequent in PCS versus ACS patients: 3.6 vs. 5.9%, odds ratio (OR) = 0.594 in the whole set, 4.4 vs. 7.8%, OR = 0.543 in those with large vessel occlusion (LVO), and 2.2 vs. 4.7%, OR = 0.463 in those without LVO. At 3 months, PCS patients compared with ACS patients achieved more frequently excellent clinical outcomes (modified Rankin scale [mRS] 0-1: 55.5 vs. 47.6%, OR = 1.371 in the whole set and 49.2 vs. 37.6%, OR = 1.307 in those with LVO), good clinical outcomes (mRS 0-2: 69.9 vs. 62.8%, OR = 1.377 in the whole set and 64.5 vs. 50.5%, OR = 1.279 in those with LVO), and had lower mortality (12.4 vs. 16.6%, OR = 0.716 in the whole set and 18.4 vs. 25.5%, OR = 0.723 in those with LVO) (p < 0.05 in all cases). In PCS versus ACS patients, an extensive analysis showed a lower risk of PH both in patients with and without LVO, more frequent excellent and good clinical outcomes, and lower mortality 3 months after IVT in patients with LVO.

Predictors for intracerebral hemorrhage after intravenous or intraarterial recanalization in acute major cerebral artery occlusion in Korean patients

OBJECTIVE

To evaluate predictors for intracerebral hemorrhage (ICH) and 1-month mortality after intravenous (IV) or intraarterial (IA) recanalization therapy for major cerebral artery occlusion in Korean patients.

METHODS

From 2011 to 2015, we prospectively gathered data from consecutive patients treated with IV/IA recanalization within 8 h of symptoms in a single center. The effects of demographic, clinical, laboratory, and radiological factors on ICH within 2 weeks were assessed, as well as 1-month mortality.

RESULTS

From a total of 183 patients, symptomatic intracerebral hemorrhage (SICH) occurred in 32 patients (17.5%), and asymptomatic ICH occurred in 37 patients (20.2%). The mortality rate at 1 month in ICH patients was 37.7%. The international normalized ratio (INR) (OR, 4.9; 95% CI, 1.03-23.4; p = 0.046), glucose (OR, 1.119 per mmol/L; 95% CI, 1.015-1.233; p = 0.023), medium-volume infarct (15-69.9 mL) (OR, 2.62; 95% CI, 1.1-6.26; p = 0.03), large-volume infarct (≥70 mL) (OR, 5.54; 95% CI, 2.1-14.6; p = 0.001), and angioplasty or stenting (OR, 6.29; 95% CI, 1.71-23.22; p = 0.006) were predictors of any ICH. Hyperlipidemia or statin medication (OR, 4.17; 95% CI, 1.38-12.59; p = 0.011), INR (OR, 7.13; 95% CI, 0.94-54.22 p = 0.058), and large-volume infarct (≥70 mL) (OR, 7.96; 95% CI, 2.31-27.39; p = 0.001) were predictors of SICH. Hypertension (OR, 5.77; 95% CI, 1.43-23.3; p = 0.014), initial NIHSS score (OR, 1.09; 95% CI, 1.01-1.18; p = 0.27), and SICH (OR, 15.7; 95% CI, 4.04-61.08; p < 0.001) were predictors of 1-month mortality.

CONCLUSION

INR and glucose may be strong modifiable predictors of critical ICH leading to death after IV/IA recanalization therapy in acute cerebral artery occlusion.

A Novel Nomogram to Predict Symptomatic Intracranial Hemorrhage in Ischemic Stroke Patients After Intravenous Thrombolysis

Objective

This study aimed to create and validate a novel nomogram to predict the risk of symptomatic intracranial hemorrhage (sICH) in patients with acute ischemic stroke (AIS) who underwent intravenous thrombolysis (IVT).

Methods

In this retrospective study, 784 patients with AIS who received IVT were enrolled. The patients were randomly divided into two groups: a training set (n=550, 70%) and a testing set (n=234, 30%). Utilizing multivariable logistic regression analysis, relevant factors for the predictive nomogram were selected. The performance of the nomogram was evaluated using various metrics, including the area under the receiver operating characteristic curve (AUC-ROC), the Hosmer-Lemeshow goodness-of-fit test, calibration plots, and decision curve analysis (DCA).

Results

Multivariable logistic regression analysis showed that specific factors, including National Institutes of Health Stroke Scale (NIHSS) scores, Early infarct signs (EIS), and serum sodium, were identified as independent predictors of sICH. Subsequently, a nomogram was constructed using these predictors. The AUC-ROC values of the nomogram were 0.864 (95% CI: 0.810-0.919) and 0.831 (95% CI: 0.770-0.891) in the training and the validation sets, respectively. Both the calibration plots and the Hosmer-Lemeshow goodness-of-fit test showed favorable agreement in both the training and the validation sets. Additionally, the DCA indicated the practical clinical utility of the nomogram.

Conclusion

The novel nomogram, which included NIHSS, EIS and serum sodium as variables, had the potential for predicting the risk of sICH in patients with AIS after IVT.

Breaking with a dogma: persisting diffusion restrictions (pDWI) in follow-up after endovascular treatment for stroke

BACKGROUND

Post-stroke diffusion weighted imaging (DWI) signal transformation of the infarct core, which results in high apparent diffusion coefficient (ADC) values and variable DWI signal intensity, is completed no later than 1 month after onset of ischemia. We observed frequent exceptions to this timeline of change in DWI signal, which led to uncertainties in further clinical patient management.

METHODS

A prospective single-center study of patients treated with mechanical thrombectomy of a large vessel occlusion in the anterior circulation was conducted. Patients received high-resolution MRI at 3T, including DWI, in the acute post-stroke phase and in the follow-up after 3-12 months.

RESULTS

Overall, 78 patients (45 men) of mean age 63.6 years were evaluated. We identified persisting or new diffusion restriction in 29 of the 78 patients (37.2%) on follow-up imaging. Diffusion restrictions in a different location from the infarct core, representing new (sub-)acute ischemia, were observed in four patients (5.1%). Smaller areas of persisting diffusion restriction (pDWI lesions with high DWI signal and reduced ADC values) within the former infarct core were observed in 25 patients (32.1%) without clinical evidence of recurrent stroke, but with worse outcome scores at follow-up compared with patients without pDWI lesions. The presence of pDWI lesions is associated with a large primary infarct core (multivariate regression OR 1.03 (95% CI 1.01 to 1.05); p<0.01), mediating the relationship between pDWI lesions and clinical outcome.

CONCLUSION

Smaller foci of persisting diffusion restriction (pDWI lesions) in the follow-up after endovascular treatment for stroke are frequent and likely represent a slowed ADC signal progression within a formerly large infarct core.

The association between the severity and distribution of white matter lesions and hemorrhagic transformation after ischemic stroke: A systematic review and meta-analysis

Background and purpose

As a part of the natural course of ischemic stroke, hemorrhagic transformation (HT) is a serious complication after reperfusion treatment, which may affect the prognosis of patients with ischemic stroke. White matter lesions (WMLs) refer to focal lesions on neuroimaging and have been suggested to indicate a high risk of HT. This systematic review and meta-analysis aimed to summarize current evidence on the relation between WML and HT.

Methods

This systematic review was prepared with reference to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. We searched PubMed, Embase, Web of Science, and Cochrane Library databases for publications on WML and HT in patients with ischemic stroke. Odds ratios (ORs) and 95% confidence intervals (CIs) from eligible studies were combined to quantify the association between the severity of WML and the risk of HT. In addition, the descriptive analysis was adopted to evaluate the influence of different WML distributions on predicting HT.

Results

A total of 2,303 articles were identified after removing duplicates through database searching, and 41 studies were included in our final analysis. The meta-analysis showed that the presence of WML was associated with HT (OR = 1.62, 95%CI 1.08-2.43, p = 0.019) and symptomatic intracerebral hemorrhage (sICH) (OR = 1.64, 95%CI 1.17-2.30, p = 0.004), and moderate-to-severe WML indicated a high risk of HT (OR = 2.03, 95%CI 1.33-3.12, p = 0.001) and sICH (OR = 1.92, 95%CI 1.31-2.81, p < 0.001). The dose-response meta-analysis revealed risk effects of increasing the severity of WML on both HT and ICH. In addition, both periventricular WML (PWML) (five of seven articles) and deep WML (DWML) (five of six articles) were shown to be associated with HT.

Conclusions

White matter lesions are associated with overall HT and sICH in patients with ischemic stroke, and more severe WMLs indicate a high risk of HT and sICH. In addition, both PWML and DWMLs could be risk factors for HT.

Systematic review registration

https://www.crd.york.ac.uk/prospero/, identifier: PROSPERO CRD42022313467.

Tenecteplase Thrombolysis in Posterior Circulation Stroke

One in five ischaemic strokes affects the posterior circulation. Basilar artery occlusion is a type of posterior circulation stroke associated with a high risk of disability and mortality. Despite its proven efficacy in ischaemic stroke more generally, alteplase only achieves rapid reperfusion in ~4% of basilar artery occlusion patients. Tenecteplase is a genetically modified variant of alteplase with greater fibrin specificity and longer half-life than alteplase, which can be administered by intravenous bolus. The single-bolus administration of tenecteplase vs. an hour-long alteplase infusion is a major practical advantage, particularly in "drip and ship" patients with basilar artery occlusion who are being transported between hospitals. Other practical advantages include its reduced cost compared to alteplase. The EXTEND-IA TNK trial demonstrated that tenecteplase led to higher reperfusion rates prior to endovascular therapy (22 vs. 10%, non-inferiority p = 0.002, superiority p = 0.03) and improved functional outcomes (ordinal analysis of the modified Rankin Scale, common odds ratio 1.7, 95% CI 1.0-2.8, p = 0.04) compared with alteplase in large-vessel occlusion ischaemic strokes. We recently demonstrated in observational data that tenecteplase was associated with increased reperfusion rates compared to alteplase prior to endovascular therapy in basilar artery occlusion [26% (n = 5/19) of patients thrombolysed with TNK vs. 7% (n = 6/91) thrombolysed with alteplase (RR 4.0 95% CI 1.3-12; p = 0.02)]. Although randomized controlled trials are needed to confirm these results, tenecteplase can be considered as an alternative to alteplase in patients with basilar artery occlusion, particularly in "drip and ship" patients.

Diffusion weighted imaging in acute ischemic stroke: A review of its interpretation pitfalls and advanced diffusion imaging application

Diffusion weighted imaging (DWI) is a widely used imaging technique to evaluate patients with stroke. It can detect brain ischemia within minutes of stroke onset. However, DWI has few potential pitfalls that should be recognized during interpretation. DWI lesion could be reversible in the early hours of stroke and the entire lesion may not represent ischemic core. False negative DWI could lead to diagnosis of DWI negative stroke or to a missed stroke diagnosis. Ischemic stroke mimics can occur on DWI with non-cerebrovascular neurological conditions. In this article, the history of DWI, its clinical applications, and potential pitfalls for use in acute ischemic stroke are reviewed. Advanced diffusion imaging techniques with reference to Diffusion Kurtosis Imaging and Diffusion Tensor Imaging that has been studied to evaluate ischemic core are discussed.

Pre-procedural predictive factors of symptomatic intracranial hemorrhage after thrombectomy in stroke

OBJECTIVE

Symptomatic intracerebral hemorrhage (sICH) is a common complication of acute ischemic stroke (AIS) associated with limited treatments and poor outcomes. We aimed to identify predictive factors of sICH in patients with AIS following mechanical thrombectomy (MT) in a real-world setting.

METHODS

Patients with large vessel occlusion of the anterior circulation treated with MT were consecutively included in a prospective monocentric cohort. Clinical, biological, and radiological parameters were collected to identify pre-procedural predictors for sICH.

RESULTS

637 patients were included in our study. Magnetic resonance imaging was performed on most patients (86.7%). sICH occurred in 55 patients (8.6%). 428 patients (67.2%) were treated with intravenous thrombolysis. After multivariate analysis, prior use of antiplatelet therapies (odd ratio (OR) 1.84, 95% confidence interval (CI) 1.01-3.32), high C-reactive protein (OR per standard deviation (SD) increase 1.28, 95% 1.01-1.63), elevated mean arterial blood pressure (OR per 10 mmHg increase 1.22, 95% CI 1.03-1.44), hyperglycemia (OR per one SD-log increase 1.38, 95% CI 1.02-1.87), and low ASPECTS (OR per 1-point decrease 1.42, 95% CI 1.12-1.80) were found to be independent predictive factors of sICH. The pre-procedural predictors did not change when the absence of successful recanalization was considered as a covariate. Patients with strokes of unknown onset time were not especially vulnerable for sICH.

CONCLUSION

sICH after MT was associated with several pre-procedural risk factors: prior use of antiplatelet therapies, high C-reactive protein and hyperglycemia at baseline, elevated mean arterial blood pressure, and low ASPECTS.

White Matter Hypoperfusion Associated with Leukoaraiosis Predicts Intracranial Hemorrhage after Intravenous Thrombolysis

OBJECTIVES

White matter hyperintensity is common in patients receiving intravenous thrombolysis. Some studies have expressed concern about the increased risk of hemorrhagic transformation and poor prognosis for those patients with pre-existing leukoaraiosis. The purpose of this study was to evaluate hypoperfusion associated with leukoaraiosis before thrombolysis using CT perfusion and to explore whether chronic white matter hypoperfusion increases risks of intracranial hemorrhage and poor clinical prognosis.

MATERIALS AND METHODS

We collected 175 patients underwent intravenous thrombolysis with complete CT perfusion data and follow-up MRI between June 2017 and January 2020. We measured cerebral blood flow, cerebral blood volume, mean transit time and transit time to the peak at both periventricular and subcortical layers in the cerebral hemisphere contralateral to the stroke. The differences of white matter perfusion were compared between groups with different leukoaraiosis severity. Univariate analysis was used to compare in incidence of hemorrhagic transformation and poor prognosis between the hypoperfusion and normal perfusion groups. Further, we examined association between white matter hypoperfusion and intracranial hemorrhage after thrombolysis using logistic regression.

RESULTS

The length of periventricular transit time to the peak was independently associated with a higher risk of intracranial hemorrhage after thrombolysis (OR=4.740, 95%CI=1.624-13.837, P=0.004). The best predictive value was 4.012. But there was no significant difference in poor prognosis at 3 months between hypoperfusion (periventricular transit time to the peak≥4.012 s) and normal perfusion (periventricular transit time to the peak<4.012 s) group.

CONCLUSIONS

Image presentations of white matter hypoperfusion reflected the severity of leukoaraiosis. White matter hypoperfusion was independently associated with intracranial hemorrhage after intravenous thrombolysis. However, hypoperfusion would not increase the risk of poor prognosis.

Incomplete or failed thrombectomy in acute stroke patients with Alberta Stroke Program Early Computed Tomography Score 0-5 - how harmful is trying?

BACKGROUND AND PURPOSE

It is currently unknown whether mechanical thrombectomy (MT) for ischaemic stroke patients with low initial Alberta Stroke Program Early Computed Tomography Score (ASPECTS) is clinically beneficial or even harmful. The purpose of this study was to investigate whether failed or incomplete MT in acute large vessel occlusion stroke with an initial ASPECTS ≤ 5 is associated with worse clinical outcome compared to patients not undergoing MT.

METHODS

This observational cohort study included a consecutive sample of patients with anterior circulation stroke and initial ASPECTS ≤ 5 admitted between March 2015 and August 2019. Failed recanalization was defined as Thrombolysis in Cerebral Infarction (TICI) score 0-2a, and incomplete recanalization as TICI 2b. Clinical outcome was assessed using the modified Rankin Scale (mRS) at 90 days defining very poor clinical outcome as mRS > 4.

RESULTS

One hundred and seventy patients were included. Ninety-nine patients underwent MT and 71 patients received best medical treatment only. Clinical outcome after failed or incomplete MT (TICI 0-2b) was significantly better compared to patients with medical treatment only (median mRS 5, interquartile range 4-6 vs 5-6, P = 0.03). In multivariable logistic regression analysis, failed or incomplete MT (TICI 0-2b) showed a significantly reduced likelihood for very poor outcome (odds ratio 0.39, 95% confidence interval 0.19-0.83, P = 0.01). Failed MT (TICI 0-2a) was not associated with a worse outcome compared to best medical treatment.

CONCLUSIONS

Patients with failed or incomplete recanalization results (TICI 0-2b) showed a reduced likelihood for very poor outcome compared with those who did not receive MT. Evidence from randomized trials is needed to confirm that even failed or incomplete MT is not harmful in these patients.

Subarachnoid Contrast Accumulation and Alberta Stroke Program Early Computed Tomography Score Applied to Contrast Accumulation After Thrombectomy as Predictors of Symptomatic Hemorrhage

BACKGROUND

Areas of contrast accumulation (CA) are commonly found on routine computed tomography (CT) performed immediately after thrombectomy. In the present study, we investigated the types of CA associated with the different outcomes, including symptomatic intracranial hemorrhage (sICH).

METHODS

The present study analyzed the data from 145 patients with anterior circulation stroke who had undergone non-contrast-enhanced conventional CT immediately after thrombectomy. The following variables were investigated: collateral status, failure of recanalization, Alberta stroke program early CT score (ASPECTS) applied to CA lesions and diffusion-weighted imaging infarct lesions, and sICH.

RESULTS

Of the 145 patients, 102 (70.3%) had CA lesions. All types of CA (any CA, cortical CA, subarachnoid CA, and CA ASPECTS) were significantly associated with poor outcomes (modified Rankin scale score >2). In particular, subarachnoid CA (odds ratio, 23.994; 95% confidence interval, 4.696-122.589) and CA ASPECTS (odds ratio, 0.550; 95% confidence interval, 0.404-0.750) were independently associated with sICH. Patients with subarachnoid CA had poorer collateral status and a larger final infarct size than those without subarachnoid CA, although the initial National Institutes of Health stroke scale score and recanalization rate were comparable between the 2 groups. A CA ASPECTS of ≤5 predicted sICH with a sensitivity of 66.7% and a specificity of 92.6% (area under the curve, 0.854).

CONCLUSIONS

Our data suggest that a subarachnoid CA location and CA ASPECTS are predictors of sICH. In particular, a subarachnoid location of CA might signify damage of the subarachnoid collateral arteries, leading to a larger infarct.

Do thrombolysis outcomes differ between anterior circulation stroke and posterior circulation stroke? A systematic review and meta-analysis

BACKGROUND

It remains unclear whether thrombolysis outcomes can be influenced by the affected vascular territory (i.e. anterior circulation stroke vs. posterior circulation stroke) in stroke patients owing to the lack of randomized controlled trials.

AIMS

Using multiple comprehensive databases, we searched for observational studies of the safety and efficacy of intravenous thrombolytics and intra-arterial treatment with or without intravenous thrombolytics in accordance with the affected vascular territory. We performed a systematic review and meta-analysis. We evaluated symptomatic intracerebral hemorrhage, all-type intracerebral hemorrhage, mortality, and functional outcomes at three months. The recanalization rate was assessed in the intra-arterial treatment group.

SUMMARY OF REVIEW

Twenty-one studies including a report from our own stroke registry were included through quantitative synthesis. Compared with the anterior circulation stroke group, the posterior circulation stroke group had a lower risk of ICH, including symptomatic intracerebral hemorrhage and all-type intracerebral hemorrhage, after intravenous thrombolytics and tended to have favorable functional outcomes at three months. Mortality was similar between the two groups. Regarding intra-arterial treatment, the symptomatic intracerebral hemorrhage and post-procedural recanalization rates were comparable between the two groups, although the posterior circulation stroke group had a higher mortality risk and lower tendency for a favorable functional outcome.

CONCLUSIONS

Safety and efficacy of thrombolysis in posterior circulation stroke depends on involvement of large vessel occlusion and reperfusion modality such that intravenous thrombolytics is more effective and safer than in anterior circulation stroke; the safety and efficacy of intra-arterial treatment is comparable or lower than anterior circulation stroke. Considering the limitations of our meta-analysis, further studies are needed to provide high level evidence of a beneficial effect of intra-arterial treatment, and to identify patients' profiles associated with benefit of treatment.

Dramatic thrombolysis after rapid injection of tissue plasminogen activator: A case report

RATIONALE

The regimen of the recombinant tissue plasminogen activator (rt-PA) is identical in every case where it is indicated in the treatment of cerebral infarction. We report a case of efficient recanalization of large arterial occlusion after rapid injection of rt-PA.

PATIENT CONCERNS

A 78-year-old man was admitted with right-sided hemiplegia and global aphasia that occurred an hour ago.

DIAGNOSES

His brain computed tomography (CT) revealed no hemorrhage, suggesting cerebral infarction.

INTERVENTIONS

Ten percent of a total rt-PA dose was injected over 1 minute promptly. The remainder of rt-PA was designed to be infused for 60 minutes. Unexpectedly, during the study of CT angiography, administration of rt-PA was completed within 5 minutes. CT angiography showed occlusion from carotid bifurcation to the middle cerebral artery.

OUTCOMES

After 2 hours of rt-PA administration, the patient began to regain strength in his right arm and leg. By the next day, he had only mild dysarthria and aphasia. Follow-up CT angiography revealed recanalized internal cervical artery and severe residual stenosis with a plaque. He was discharged without any neurologic symptoms.

LESSONS

The infusion protocol of rt-PA administration is established in 1995 and has not changed. Successful recanalization of long segmental large vessel occlusion with only intravenous rt-PA is relatively low. In our case, a high concentration of rt-PA may have influenced the successful dissemination of large thrombus in the whole internal cervical artery. Our case is of significance as it raises the question of unanswered efficacy of diverse injection protocol according to thrombus size and bleeding risk.

Cohort profile: Thrombolysis in Ischemic Stroke Patients (TRISP): a multicentre research collaboration

PURPOSE

The ThRombolysis in Ischemic Stroke Patients (TRISP) collaboration aims to address clinically relevant questions about safety and outcomes of intravenous thrombolysis (IVT) and endovascular thrombectomy. The findings can provide observational information on treatment of patients derived from everyday clinical practice.

PARTICIPANTS

TRISP is an open, investigator-driven collaborative research initiative of European stroke centres with expertise in treatment with revascularisation therapies and maintenance of hospital-based registries. All participating centres made a commitment to prospectively collect data on consecutive patients with stroke treated with IVT using standardised definitions of variables and outcomes, to assure accuracy and completeness of the data and to adapt their local databases to answer novel research questions.

FINDINGS TO DATE

Currently, TRISP comprises 18 centres and registers >10 000 IVT-treated patients. Prior TRISP projects provided evidence on the safety and functional outcome in relevant subgroups of patients who were excluded, under-represented or not specifically addressed in randomised controlled trials (ie, pre-existing disability, cervical artery dissections, stroke mimics, prior statin use), demonstrated deficits in organisation of acute stroke care (ie, IVT during non-working hours, effects of onset-to-door time on onset-to-needle time), evaluated the association between laboratory findings on outcome after IVT and served to develop risk estimation tools for prediction of haemorrhagic complications and functional outcome after IVT.

FUTURE PLANS

Further TRISP projects to increase knowledge of the effect and safety of revascularisation therapies in acute stroke are ongoing. TRISP welcomes participation and project proposals of further centres fulfilling the outlined requirements. In the future, TRISP will be extended to include patients undergoing endovascular thrombectomy.

Optimal Delay Time of CT Perfusion for Predicting Cerebral Parenchymal Hematoma After Intra-Arterial tPA Treatment

Background and Purpose: Cerebral hemorrhage is a serious potential complication of stroke revascularization, especially in patients receiving intra-arterial tissue-type plasminogen activator (tPA) therapy. We investigated the optimal pre-intervention delay time (DT) of computed tomography perfusion (CTP) measurement to predict cerebral parenchymal hematoma (PH) in acute ischemic stroke (AIS) patients after intra-arterial tissue plasminogen activator (tPA) treatment.

Methods: The study population consisted of a series of patients with AIS who received intra-arterial tPA treatment and had CTP and follow-up computed tomography/magnetic resonance imaging (CT/MRI) to identify hemorrhagic transformation. The association of increasing DT thresholds (>2, >4, >6, >8, and >10 s) with PH was examined using receiver operating characteristic (ROC) analysis and logistic regression.

Results: Of 94 patients, 23 developed PH on follow-up imaging. Receiver operating characteristic analysis revealed that the greatest area under the curve for predicting PH occurred at DT > 4 s (area under the curve, 0.66). At this threshold of > 4 s, DT lesion volume ≥ 30.85 mL optimally predicted PH with 70% sensitivity and 59% specificity. DT > 4 s volume was independently predictive of PH in a multivariate logistic regression model (P < 0.05).

Conclusions: DT > 4 s was the parameter most strongly associated with PH. The volume of moderate, not severe, hypo-perfusion on DT is more strongly associated and may allow better prediction of PH after intra-arterial tPA thrombolysis.

Safety of Recanalization Therapy in Patients with Acute Ischemic Stroke Under Anticoagulation: A Systematic Review and Meta-Analysis

BACKGROUND

Intravenous thrombolysis treatment (IVT) and endovascular therapy (EVT) have been proved as fist-line beneficial option for eligible patients who have acute ischemic stroke (AIS) with major safety concern of symptomatic intracranial hemorrhage (sICH). Unfortunately, the emergency management of patients with AIS taking vitamin K antagonists and with international normalized ratio higher than 1.7 or taking new oral anticoagulants (NOACs) represents a great challenge. We aim to comprehensively determine the safety of EVT in patients under prior-stroke anticoagulants and IVT in patients under NOAC use.

METHODS

Clinical researches published in the Embase, PubMed, and Cochrane Library electronic databases up to December 2017 were identified for analysis. Subgroup and sensitivity analyses were also conducted to evaluate the robustness of the conclusions.

RESULTS

Overall, 9 studies involving 3885 patients met the inclusion criteria. The rate of sICH (risk ratio [RR] = .94, 95% CI = .61-1.47, P = .799), mortality (P = .495), and recanalization (P = .655) after EVT did not differ between patients under and those who were not under anticoagulants, although patients under anticoagulants were less likely to achieve good functional outcome (P < .001) than those who were not. Moreover, prior NOAC therapy was not significantly associated with increasing sICH in patients with AIS after IVT (RR = .79, 95% CI = .41-1.53, P = .492).

CONCLUSIONS

Patients under anticoagulation appear to be safe after EVT with relatively lower rate of good outcome; furthermore, prior NOAC therapy was not associated with an increasing sICH rate after IVT. This offered a practical information to select appropriate therapeutic strategies for patients under anticoagulation, although the level of evidence seems to be quite shaky.

Severe cerebral hypovolemia on perfusion CT and lower body weight are associated with parenchymal haemorrhage after thrombolysis

INTRODUCTION

Haemorrhagic transformation of acute ischemic stroke (AIS) and particularly parenchymal haemorrhage (PH) remains a feared complication of intravenous thrombolysis (IVT). We aimed to identify clinical and perfusion CT (PCT) variables which are independently associated with PHs.

METHODS

In this observational cohort study, based on the Acute Stroke Registry Analysis of Lausanne (ASTRAL) from 2003 to December 2013, we selected patients with AIS involving the middle cerebral artery (MCA) territory who were thrombolysed within 4.5 h of symptoms' onset and who had a good quality baseline PCT at the beginning of IVT. In addition to demographic, clinical, laboratory and non-contrast CT data, volumes of salvageable tissue and ischemic core on PCT, as well as absolute CBF and CBV values within the ischemic regions were compared in patients with and without PH in multivariate analysis.

RESULTS

Of the 190 included patients, 24 (12.6%) presented a PH (11 had PH1 and 13 had PH2). In multivariate analysis of the clinical and radiological variables, the lowest CBV in the core and lower body weight was both significantly associated with PH (p = 0.009 and p = 0.024, respectively).

CONCLUSION

In thrombolysed MCA strokes, maximal hypoperfusion severity depicted by lowest CBV values in the core region and lower body weight are independently correlated with PH. This information, if confirmed in other case series, may add to the stratification of revascularisation decisions in patients with a perceived high PH risk.

Optimizing Outcomes for Mechanically Ventilated Patients in an Era of Endovascular Acute Ischemic Stroke Therapy

Endovascular mechanical thrombectomy is a new standard of care for acute ischemic stroke (AIS). The majority of these patients receive mechanical ventilation (MV), which has been associated with poor outcomes. The implication of this is significant, as most neurointerventionalists prefer general compared to local anesthesia during the procedure. Consequences of hemodynamic and respiratory perturbations during general anesthesia and MV are thought to contribute significantly to the poor outcomes that are encountered. In this review, we first describe the unique risks associated with MV in the specific context of AIS and then discuss evidence of brain goal-directed approaches that may mitigate these risks. These strategies include an individualized approach to hemodynamic parameters (eg, adherence to a minimum blood pressure goal and adequate volume resuscitation), respiratory parameters (eg, arterial carbon dioxide optimization), and the use of ventilator settings that optimize neurological outcomes (eg, arterial oxygen optimization).

Impact of leukoaraiosis on parenchymal hemorrhage in elderly patients treated with thrombolysis

INTRODUCTION

Severity of vascular damage of white matter may predict hemorrhagic transformation (HT). We assess the relationship between leukoaraiosis (LA) severity and the type of hemorrhagic transformation in elderly patients treated with thrombolysis.

METHODS

We retrospectively analyzed the clinical data and pretreatment magnetic resonance imaging (MRI) of 180 consecutive ischemic stroke patients aged over 75 years. LA severity was graded according to the Fazekas scale, and acute diffusion-weighted-imaging (DWI) lesion volumes were semi-automatically outlined. Predictors of hemorrhagic infarction (HI) and parenchymal hemorrhage (PH) were identified using logistic regression analysis and exact multinomial logistic analysis.

RESULTS

HT occurred in 31 patients (17 %). Baseline National Institute of Health Stroke Score (NIHSS; p = 0.008), severe LA (p = 0.02), and diffusion lesion volume (p = 0.02) were predictors of HT in univariable logistic regression. Adjusted to lesion volume and baseline NIHSS score, exact multinomial logistic analysis showed that severe LA was the only independent predictor of parenchymal hemorrhage (p = 0.03).

CONCLUSION

In elderly patients, LA severity better predicts parenchymal hemorrhage than infarct size.

The Oxfordshire Community Stroke Project classification system predicts clinical outcomes following intravenous thrombolysis: a prospective cohort study

Background

The Oxfordshire Community Stroke Project (OCSP) classification system is a simple stroke classification system that can be used to predict clinical outcomes. In this study, we compare the safety and efficacy of intravenous thrombolysis in Chinese stroke patients categorized using the OCSP classification system.

Patients and methods

We collected data from the Thrombolysis Implementation and Monitoring of Acute Ischemic Stroke in China registry. A total of 1,115 patients treated with intravenous thrombolysis with alteplase within 4.5 hours of stroke onset were included. Symptomatic intracranial hemorrhage (SICH), mortality, and 90-day functional outcomes were compared between the stroke patients with different stroke subtypes.

Results

Of the 1,115 patients included in the cohort, 197 (17.67%) were classified with total anterior circulation infarct (TACI), 700 (62.78%) with partial anterior circulation infarct, 153 (13.72%) with posterior circulation infarct, and 65 (5.83%) with lacunar infarct. After multivariable adjustment, compared to the patients with non-TACI, those with TACI had a significantly increased risk of SICH (odds ratio [OR] 8.80; 95% confidence interval [CI] 2.84–27.25, P<0.001), higher mortality (OR 5.24; 95% CI 3.19–8.62; P<0.001), and poor functional independence (OR 0.38; 95% CI 0.26–0.56; P<0.001) at 3-month follow-up.

Conclusion

After thrombolysis, the patients with TACI exhibited greater SICH, a higher mortality rate, and worse 3-month clinical outcomes compared with the patients with non-TACI. The OCSP classification system may help clinicians predict the safety and efficacy of thrombolysis.

Intravenous thrombolysis is more safe and effective for posterior circulation stroke: Data from the Thrombolysis Implementation and Monitor of Acute Ischemic Stroke in China (TIMS-China)

We aimed to compare the safety and efficacy of intravenous thrombolysis (IVT) with alteplase for anterior circulation stroke (ACS) and posterior circulation stroke (PCS). From a large multicenter prospective registry-the Thrombolysis Implementation and Monitor of Acute Ischemic Stroke in China database-all patients who received IVT within 4.5 hours after stroke onset was reviewed. According to the clinical presentations and imaging findings, the eligible patients were divided into ACS and PCS groups. The safety and efficacy outcome measures included post-IVT symptomatic intracranial hemorrhage (sICH), parenchymal hematoma, and all intracranial hemorrhage (aICH) within 7 days, mortality within 90 days, excellent recovery (modified Rankin Scale 0-1), and functional independence (modified Rankin Scale 0-2) at 90 days. For comparing the outcomes between both groups, the odds ratios (ORs) with 95% confidence intervals (CIs) and the adjusted ORs with 95% CIs were analyzed by univariate and multivariate logistic regression models. Of 953 patients enrolled, 829 patients had ACS and 124 had PCS. The patients with PCS had less often atrial fibrillation (11.3% vs 19.8%; P = 0.02), higher blood glucose level (8.31 vs 7.63 mmol/L; P = 0.02), and more white blood cell counts (8.79 vs 7.75 × 10/L; P = 0.001) than those with ACS. After adjustment for the potential confounders, multivariate logistic analysis showed that PCS patients had not only lower rates of sICH (3.2% vs 7.7%; OR 0.28, 95% CI 0.09-0.90), parenchymal hematoma (1.6% vs 9.2%; OR 0.13, 95% CI 0.03-0.57), and aICH (8.1% vs 20.4%; OR 0.26, 95% CI 0.12-0.54), but also higher proportions of excellent recovery (55.7% vs 41.6%; OR 2.27, 95% CI 1.42-3.61) and functional independence (63.9% vs 53.0%; OR 2.33, 95% CI 1.40-3.89) compared with ACS patients. However, there was no significant difference in the occurrence of mortality (OR 0.86, 95% CI 0.39-1.91) between both groups in the multivariate model, although more PCS patients seemed to die within 90 days than did ACS patients (15.6% vs 10.1%; OR 1.64, 95% CI 0.96-2.82) in the univariate analysis. Our study suggests that IVT with alteplase is more safe and effective for PCS.

Early neurological deterioration after thrombolysis: Clinical and imaging predictors

BACKGROUND

National Institutes of Health Stroke Scale is the most common scale used in stroke patients. An increase of four points or more within 24 h signifies early neurological deterioration. We aimed to establish how often early neurological deterioration occurs in a cohort selected by magnetic resonance imaging and which factors predicted early neurological deterioration.

METHODS

In this single-center study, we collected epidemiological, imaging and outcome data on 569 consecutive patients undergoing reperfusion therapy after magnetic resonance imaging selection.

RESULTS

Of these, 33 (5.8%) experienced early neurological deterioration. Seven were due to a symptomatic intracerebral hemorrhage, 23 were caused by extension of ischemia on follow-up imaging and three were due to progression on the basis of small vessel disease. Early neurological deterioration was predicted by a larger perfusion lesion, higher blood glucose and presence of large vessel disease. Penumbra occurred in 34% of patients but only 9% of patients with penumbra experienced early neurological deterioration, thus eroding the value of penumbra as an imaging marker. Early neurological deterioration was a poor prognostic sign. Odds ratio for disability or death was 14.9 (95% confidence interval: 6.5-34.0).

CONCLUSION

Early neurological deterioration is rare. It originates mainly from ischemic infarct growth rather than from hemorrhage. Concern should be highest in patients with elevated blood glucose, larger perfusion lesions and large vessel disease. Prior aspirin use increases risk of symptomatic intracerebral hemorrhage.

The challenge of basilar artery occlusion wake-up stroke: too late for intravenous thrombolysis?

We describe the case of a patient carried to our emergency department, with the wake-up finding of dysarthria, right hemiplegia and worsening consciousness impairment (NIHSS 12). After performing a CT angiography, which showed complete basilar occlusion, we determined the MR DWI-FLAIR mismatch to estimate the stroke onset time. Because of the favorable mismatch (DWI hyperintensity in the left pons, no FLAIR hyperintensity in the same region), the patient underwent thrombolysis with sudden neurological improvement. In addition, the DWI hyperintensity first observed in the left pons totally regressed after thrombolysis. Wake-up stroke constitutes about 14 % of all strokes, while the percentage of basilar artery occlusion wake-up strokes is still unknown. Although thrombolysis in patients with unknown-onset time is still an off-label therapy, basilar artery occlusion is a potentially fatal event. In our case we used RM DWI-FLAIR mismatch to rapidly estimate the stroke onset time and to treat the patient with an off-label but potentially effective and safe therapy.

Global White Matter Hypoperfusion on CT Predicts Larger Infarcts and Hemorrhagic Transformation after Acute Ischemia

INTRODUCTION

Presence of white matter hyperintensity (WMH) on MRI is a marker of cerebral small vessel disease and is associated with increased small vessel stroke and increased risk of hemorrhagic transformation (HT) after thrombolysis.

AIM

We sought to determine whether white matter hypoperfusion (WMHP) on perfusion CT (CTP) was related to WMH, and if WMHP predisposed to acute lacunar stroke subtype and HT after thrombolysis.

METHODS

Acute ischemic stroke patients within 12 h of symptom onset at 2 centers were prospectively recruited between 2011 and 2013 for the International Stroke Perfusion Imaging Registry. Participants routinely underwent baseline CT imaging, including CTP, and follow-up imaging with MRI at 24 h.

RESULTS

Of 229 ischemic stroke patients, 108 were Caucasians and 121 Chinese. In the contralateral white matter, patients with acute lacunar stroke had lower cerebral blood flow (CBF) and cerebral blood volume (CBV), compared to those with other stroke subtypes (P = 0.041). There were 46 patients with HT, and WMHP was associated with increased risk of HT (R(2) = 0.417, P = 0.002). Compared to previously reported predictors of HT, WMHP performed better than infarct core volume (R(2) = 0.341, P = 0.034), very low CBV volume (R(2) = 0.249, P = 0.026), and severely delayed perfusion (Tmax>14 second R(2) = 0.372, P = 0.011). Patients with WMHP also had larger acute infarcts and increased infarct growth compared to those without WMHP (mean 28 mL vs. 13 mL P < 0.001).

CONCLUSION

White matter hypoperfusion remote to the acutely ischemic region on CTP is a marker of small vessel disease and was associated with increased HT, larger acute infarct cores, and greater infarct growth.

Imaging acute ischemic stroke

Acute ischemic stroke is common and often treatable, but treatment requires reliable information on the state of the brain that may be provided by modern neuroimaging. Critical information includes: the presence of hemorrhage; the site of arterial occlusion; the size of the early infarct "core"; and the size of underperfused, potentially threatened brain parenchyma, commonly referred to as the "penumbra." In this chapter we review the major determinants of outcomes in ischemic stroke patients, and the clinical value of various advanced computed tomography and magnetic resonance imaging methods that may provide key physiologic information in these patients. The focus is on major strokes due to occlusions of large arteries of the anterior circulation, the most common cause of a severe stroke syndrome. The current evidence-based approach to imaging the acute stroke patient at the Massachusetts General Hospital is presented, which is applicable for all stroke types. We conclude with new information on time and stroke evolution that imaging has revealed, and how it may open the possibilities of treating many more patients.

Relationships Between Imaging Assessments and Outcomes in Solitaire With the Intention for Thrombectomy as Primary Endovascular Treatment for Acute Ischemic Stroke

BACKGROUND AND PURPOSE

Imaging findings can predict outcomes in patients with acute stroke. Relationships between imaging findings and clinical and imaging outcomes in patients randomized to intravenous tissue-type plasminogen activator-alone versus tissue-type plasminogen activator plus endovascular therapy (Solitaire device) in the Solitaire With the Intention for Thrombectomy as Primary Endovascular Treatment for Acute Ischemic Stroke (SWIFT PRIME) study were assessed.

METHODS

We evaluated associations between imaging assessments (baseline mismatch profiles/ischemic core volumes and successful reperfusion) with imaging outcomes (27-hour infarct volume/growth) and clinical outcomes (modified Rankin Scale scores at 90 days). Imaging variables that predict favorable clinical outcomes were assessed in both univariate and multivariate models.

RESULTS

One hundred and ninety-five patients were included. Successful reperfusion and infarct volume (assessed at 27 hours) were powerful independent predictors of favorable clinical outcomes (modified Rankin Scale score of 0-2 at 90 days). Patients with the target mismatch profile at baseline had a higher rate of reperfusion, lesser infarct growth, smaller infarct volumes, and better clinical outcomes in the Solitaire plus tissue-type plasminogen activator (intervention) group than those in the tissue-type plasminogen activator-alone (control) group. Patients with larger mismatch volumes at baseline had a trend toward better treatment response in the intervention group than patients who had smaller (<50 mL) mismatch volumes.

CONCLUSIONS

Patients who achieved reperfusion had substantially more favorable clinical and imaging outcomes in both the intervention and the control groups. Infarct volume at 27 hours strongly correlated with clinical outcome at 90 days in both treatment groups. SWIFT PRIME patients with the target mismatch profile had a highly favorable response to endovascular therapy on both clinical and imaging outcomes. Both reperfusion and infarct volumes at 27 hours were powerful and independent predictors of 90-day clinical outcomes.

CLINICAL TRIAL REGISTRATION

URL: http://www.clinicaltrials.gov. Unique identifier: NCT01657461.

Younger Stroke Patients With Large Pretreatment Diffusion-Weighted Imaging Lesions May Benefit From Endovascular Treatment

BACKGROUND AND PURPOSE

Lesion volume on diffusion-weighted magnetic resonance imaging (DWI) before acute stroke therapy is a predictor of outcome. Therefore, patients with large volumes are often excluded from therapy. The aim of this study was to analyze the impact of endovascular treatment in patients with large DWI lesion volumes (>70 mL).

METHODS

Three hundred seventy-two patients with middle cerebral or internal carotid artery occlusions examined with magnetic resonance imaging before treatment since 2004 were included. Baseline data and 3 months outcome were recorded prospectively. DWI lesion volumes were measured semiautomatically.

RESULTS

One hundred five patients had lesions >70 mL. Overall, the volume of DWI lesions was an independent predictor of unfavorable outcome, survival, and symptomatic intracerebral hemorrhage (P<0.001 each). In patients with DWI lesions >70 mL, 11 of 31 (35.5%) reached favorable outcome (modified Rankin scale score, 0-2) after thrombolysis in cerebral infarction 2b-3 reperfusion in contrast to 3 of 35 (8.6%) after thrombolysis in cerebral infarction 0-2a reperfusion (P=0.014). Reperfusion success, patient age, and DWI lesion volume were independent predictors of outcome in patients with DWI lesions >70 mL. Thirteen of 66 (19.7%) patients with lesions >70 mL had symptomatic intracerebral hemorrhage with a trend for reduced risk with avoidance of thrombolytic agents.

CONCLUSIONS

There was a growing risk for poor outcome and symptomatic intracerebral hemorrhage with increasing pretreatment DWI lesion volumes. Nevertheless, favorable outcome was achieved in every third patient with DWI lesions >70 mL after successful endovascular reperfusion, whereas after poor or failed reperfusion, outcome was favorable in only every 12th patient. Therefore, endovascular treatment might be considered in patients with large DWI lesions, especially in younger patients.

[Neurovisualisation predictors of malignant cerebral infarction and hemorrhagic transformation]

Neuroimaging plays a central role in the assessment of patients with acute ischemic stroke. Within a few minutes, modern multimodal imaging protocols can provide one with comprehensive information about prognosis, management, and outcome of the disease, and may detect changes in the intracranial structures reflecting severity of the ischemic injury depicted by four Ps: parenchyma (of the brain), pipes (i.e., the cerebral blood vessels), penumbra, and permeability (of the blood brain barrier). In this article, we have reviewed neuroradiological predictors of malignant middle cerebral artery infarction and hemorrhagic transformation in light of the aforementioned four Ps.

Endovascular stent thrombectomy: the new standard of care for large vessel ischaemic stroke

BACKGROUND

Results of initial randomised trials of endovascular treatment for ischaemic stroke, published in 2013, were neutral but limited by the selection criteria used, early-generation devices with modest efficacy, non-consecutive enrollment, and treatment delays.

RECENT DEVELOPMENTS

In the past year, six positive trials of endovascular thrombectomy for ischaemic stroke have provided level 1 evidence for improved patient outcome compared with standard care. In most patients, thrombectomy was performed in addition to thrombolysis with intravenous alteplase, but benefits were also reported in patients ineligible for alteplase treatment. Despite differences in the details of eligibility requirements, all these trials required proof of major vessel occlusion on non-invasive imaging and most used some imaging technique to exclude patients with a large area of irreversibly injured brain tissue. The results indicate that modern thrombectomy devices achieve faster and more complete reperfusion than do older devices, leading to improved clinical outcomes compared with intravenous alteplase alone. The number needed to treat to achieve one additional patient with independent functional outcome was in the range of 3·2-7·1 and, in most patients, was in addition to the substantial efficacy of intravenous alteplase. No major safety concerns were noted, with low rates of procedural complications and no increase in symptomatic intracerebral haemorrhage. WHERE NEXT?: Thrombectomy benefits patients across a range of ages and levels of clinical severity. A planned meta-analysis of individual patient data might clarify effects in under-represented subgroups, such as those with mild initial stroke severity or elderly patients. Imaging-based selection, used in some of the recent trials to exclude patients with large areas of irreversible brain injury, probably contributed to the proportion of patients with favourable outcomes. The challenge is how best to implement imaging in clinical practice to maximise benefit for the entire population and to avoid exclusion of patients with smaller yet clinically important potential to benefit. Although favourable imaging identifies patients who might benefit despite long delays from symptom onset to treatment, the proportion of patients with favourable imaging decreases with time. Health systems therefore need to be reorganised to deliver treatment as quickly as possible to maximise benefits. On the basis of available trial data, intravenous alteplase remains the initial treatment for all eligible patients within 4·5 h of stroke symptom onset. Those patients with major vessel occlusion should, in parallel, proceed to endovascular thrombectomy immediately rather than waiting for an assessment of response to alteplase, because minimising time to reperfusion is the ultimate aim of treatment.

Receptor for Advanced Glycation End-Product Antagonist Reduces Blood–Brain Barrier Damage After Intracerebral Hemorrhage

Background and Purpose—

To determine whether the receptor for advanced glycation end-products (RAGE) plays a role in early brain injury from intracerebral hemorrhage (ICH), RAGE expression and activation after injury were examined in a rat model of ICH with or without administration of a RAGE-specific antagonist (FPS-ZM1).

Methods—

Autologous arterial blood was injected into the basal ganglia of rats to induce ICH. The motor function of the rats was examined, and water content was detected after euthanization. Blood–brain barrier permeability was determined by Evans blue staining and colloidal gold nanoparticle tracers. Nerve fiber injury in white matter was determined by diffusion tensor imaging analysis, and the expression of target genes was analyzed by Western blotting and quantitative reverse transcription polymerase chain reaction. FPS-ZM1 was administered by intraperitoneal injection.

Results—

Expression of RAGE and its ligand high-mobility group protein B1 were increased at 12 hours after ICH, along with blood–brain barrier permeability and perihematomal nerve fiber injury. RAGE and nuclear factor-κB p65 upregulation were also observed when FeCl 2 was infused into the basal ganglia at 24 hours. FPS-ZM1 administration resulted in significant improvements of blood–brain barrier damage, brain edema, motor dysfunction, and nerve fiber injury, and the expression of RAGE, nuclear factor-κB p65, proinflammatory mediators interleukin 1β, interleukin-6, interleukin-8R, cyclooxygenase-2, inducible nitric oxide synthase, and matrix metallopeptidase-9 was attenuated. Moreover, decreases in claudin-5 and occludin expression were partially recovered. FPS-ZM1 also reversed FeCl 2 -induced RAGE and nuclear factor-κB p65 upregulation.

Conclusions—

RAGE signaling is involved in blood–brain barrier and white matter fiber damage after ICH, the initiation of which is associated with iron. RAGE antagonists represent a novel therapeutic intervention to prevent early brain injury after ICH.

Reperfusion of very low cerebral blood volume lesion predicts parenchymal hematoma after endovascular therapy

BACKGROUND AND PURPOSE

Ischemic stroke patients with regional very low cerebral blood volume (VLCBV) on baseline imaging have increased risk of parenchymal hemorrhage (PH) after intravenous alteplase-induced reperfusion. We developed a method for automated detection of VLCBV and examined whether patients with reperfused-VLCBV are at increased risk of PH after endovascular reperfusion therapy.

METHODS

Receiver operating characteristic analysis was performed to optimize a relative CBV threshold associated with PH in patients from the Diffusion and Perfusion Imaging Evaluation for Understanding Stroke Evolution 2 (DEFUSE 2) study. Regional reperfused-VLCBV was defined as regions with low relative CBV on baseline imaging that demonstrated normal perfusion (Tmax <6 s) on coregistered early follow-up magnetic resonance imaging. The association between VLCBV, regional reperfused-VLCBV and PH was assessed in univariate and multivariate analyses.

RESULTS

In 91 patients, the greatest area under the curve for predicting PH occurred at an relative CBV threshold of <0.42 (area under the curve, 0.77). At this threshold, VLCBV lesion volume ≥3.55 mL optimally predicted PH with 94% sensitivity and 63% specificity. Reperfused-VLCBV lesion volume was more specific (0.74) and equally sensitive (0.94). In total, 18 patients developed PH, of whom 17 presented with VLCBV (39% versus 2%; P=0.001), all of them had regional reperfusion (47% versus 0%; P=0.01), and 71% received intravenous alteplase. VLCBV lesion (odds ratio, 33) and bridging with intravenous alteplase (odds ratio, 3.8) were independently associated with PH. In a separate model, reperfused-VLCBV remained the single independent predictor of PH (odds ratio, 53).

CONCLUSIONS

These results suggest that VLCBV can be used for risk stratification of patients scheduled to undergo endovascular therapy in trials and routine clinical practice.

Predicting intracerebral hemorrhage by baseline magnetic resonance imaging in stroke patients undergoing systemic thrombolysis

Objectives

Intracerebral hemorrhage (ICH) remains a serious complication in ischemic stroke patients undergoing systemic thrombolysis. Here, we examined whether the risk of treatment-associated hemorrhage can be predicted from magnetic resonance imaging (MRI) using fluid-attenuated inversion recovery (FLAIR) and diffusion-weighted imaging (DWI) within 3 h after symptom onset.

Methods

In this single-center observational study involving 122 ischemic stroke patients between January 2005 and December 2008, the incidence of FLAIR-positive lesions within diffusion-restricted areas was determined on baseline MRI, which was carried out prior to treatment with tissue plasminogen activator (Actilyse®) within 3 h from symptom onset. The rate of ICH was assessed by computed tomography performed within 24 h after treatment. Relationships between FLAIR-positive lesions, DWI lesion size, proportion of FLAIR/DWI-positive lesions, and occurrence of bleeding were explored.

Results

Data from 97 patients were evaluated. FLAIR-positive lesions were present in 25 patients (25.8%) and ICH occurred in 32 patients (33.0%). FLAIR-positive lesions were associated with a bleeding rate of 80.0% compared with 16.7% in FLAIR-negative patients (P < 0.001; odds ratio 20.0, positive predictive value 0.8). DWI lesion size was significantly correlated with the rate of ICH (P = 0.001). In contrast, FLAIR/DWI proportion was not associated with ICH (P = 0.788).

Conclusions

In ischemic stroke patients within 3 h from symptom onset, the existence of FLAIR-positive lesions on pretreatment MRI is significantly associated with an increased bleeding risk due to systemic thrombolysis. Therefore, considering FLAIR-positive lesions on baseline MRI might guide treatment decisions in ischemic stroke.

Collateral flow and brain changes on computed tomography angiography predict infarct volume on early diffusion-weighted imaging

BACKGROUND

We investigated whether a computed tomography (CT)-based score could predict a large infarct (≥ 80 mL) on early diffusion-weighted magnetic resonance imaging (DWI).

METHODS

Acute stroke patients considered for endovascular therapy within 8 hours of the onset of symptoms were included. The Alberta Stroke Program Early Computed Tomography Score (ASPECTS) was determined on noncontrast CT and computed tomography angiography source images (CTA-SI). Limited collateral flow was defined as less than 50% collateral filling on CTA-SI.

RESULTS

Fifty-six patients were analyzed. National Institutes of Health Stroke Scale score was 20 (15-24) in the large infarct group and 16 (11-20) in the small infarct group (P = .049). ASPECTS on noncontrast CT and CTA-SI was 5 (3-8) and 3 (2-6) in the large infarct group and 9 (8-10) and 8 (7-9) in the small infarct group (both P < .001), respectively. Limited collateral flow was frequent in the large infarct group than in the small infarct group (92% vs. 11%, P < .001). Multivariate analysis found that CTA-SI ASPECTS less than or equal to 5 (odds ratio [OR], 40.55; 95% confidence interval [CI], 1.10-1493.44; P = .044) and limited collateral flow (OR, 114.64; 95% CI, 1.93-6812.79; P = .023) were associated with a large infarct. Absence of ASPECTS less than or equal to 5 and limited collateral flow on CTA-SI predicted absence of a large infarct with a sensitivity of .89, specificity of 1.00, positive predictive value of 1.00, and negative predictive value of .71.

CONCLUSIONS

Assessment of ASPECTS and collateral flow on CTA-SI may be able to exclude a patient with large infarct on early DWI.

Number of Cerebral Microbleeds and Risk of Intracerebral Hemorrhage After Intravenous Thrombolysis

Background and Purpose—

Cerebral microbleeds (CMBs) are found in a substantial proportion of patients with ischemic stroke eligible for treatment with intravenous thrombolysis. Until now, there is limited data on the impact of multiple CMBs on occurrence of intracerebral hemorrhage (ICH) after intravenous thrombolysis.

Methods—

Between 2008 and 2013, all patients receiving MRI-based intravenous thrombolysis were identified within our prospective thrombolysis register. Number of CMBs was rated on pretreatment T2*-weighted MRI by a rater blinded to clinical data and follow-up. Outcomes of interest were occurrence of symptomatic ICH (sICH) and parenchymal hemorrhage (PH).

Results—

Among 326 included patients, 52 patients had a single CMB (16.0%), 19 had 2 to 4 CMBs (5.8%), and 10 had ≥5 CMBs (3.1%). Frequency of sICH/PH was 1.2%/5.7% in patients without CMBs, 3.8%/3.8% in patients with a single CMB, 10.5%/21.1% in patients with 2 to 4 CMBs, and 30.0%/30.0% in patients with ≥5 CMBs, respectively (each P for trend <0.01). The unadjusted odds ratio per additional CMB for sICH was 1.19 (95% confidence interval, 1.07–1.33; P <0.01) and for PH was 1.13 (95% confidence interval, 1.03–1.24; P =0.01). Compared with patients without CMBs, both patients with 2 to 4 CMBs ( P =0.02/ P =0.02) and patients with ≥5 CMBs ( P <0.01/ P <0.01) had significantly increased odds ratios for sICH and PH, whereas in patients with a single CMB, odds ratios were not significantly increased ( P =0.21/ P =0.59). The association of CMB burden with sICH/PH remained significant after adjustment for possible confounders (age, age-related white matter changes score, atrial fibrillation, onset-to-treatment time, prior statin use, and systolic blood pressure on admission).

Conclusions—

Our findings indicate a higher risk of sICH and PH after intravenous thrombolysis when multiple CMBs are present, with a graded relationship to increasing baseline CMB number.

MRI before intraarterial therapy in ischemic stroke: feasibility, impact, and safety

Intraarterial therapy (IAT) in acute ischemic stroke is effective for opening occlusions of major extracranial or intracranial vessels. Clinical efficacy data are lacking pointing to a need for proper patient selection. We examined feasibility, clinical impact, and safety profile of magnetic resonance imaging (MRI) for patient selection before IAT. In this single-center study, we collected epidemiologic, imaging, and outcome data on all intraarterial-treated patients presenting with anterior circulation occlusions at our center from 2004 to 2011. Magnetic resonance imaging was the first imaging choice. Computer tomography (CT) was performed in the presence of a contraindication. We treated 138 patients. Mean age was 64 years and median National Institutes of Health Stroke Scale (NIHSS) was 17. Major reperfusion (thrombolysis in cerebral infarction (TICI) 2b+3) was achieved in 52% and good outcome defined as modified Rankin Scale (mRS) score 0 to 2 at 90 days was achieved in 41%. Mortality at 90 days was 10%. There was only one symptomatic hemorrhage. Recanalization, age, and stroke severity were associated with outcome. Preprocedure MRI was obtained in 83%. Good outcome was significantly associated with smaller diffusion-weighted imaging (DWI) lesion size at presentation and not with the size of the perfusion lesion. It is feasible to triage patients for IAT using MRI with acceptable rates of poor outcome and symptomatic hemorrhage.

Wake-up stroke: clinical characteristics, imaging findings, and treatment option - an update

About 25% of all strokes occur during sleep, i.e., without knowledge of exact time of symptom onset. According to licensing criteria, this large group of patients is excluded from treatment with received tissue-plasminogen activator, the only specific stroke treatment proven effective in large randomized trials. This paper reviews clinical and imaging characteristics of wake-up stroke and gives an update on treatment options for these patients. From clinical and imaging studies, there is evidence suggesting that many wake-up strokes occur close to awakening and thus, patients might be within the approved time-window of thrombolysis when presenting to the emergency department. Several imaging approaches are suggested to identify wake-up stroke patients likely to benefit from thrombolysis, including non-contrast CT, CT-perfusion, penumbral MRI, and the recent concept of diffusion weighted imaging-fluid attenuated inversion recovery (DWI-FLAIR). A number of small case series and observational studies report results of thrombolysis in wake-up stroke, and no safety concerns have occurred, while conclusions on efficacy cannot be drawn from these studies. To this end, there are ongoing clinical trials enrolling wake-up stroke patients based on imaging findings, i.e., the DWI-FLAIR-mismatch (WAKE-UP) or penumbral imaging (EXTEND). The results of these trials will provide evidence to guide thrombolysis in wake-up stroke and thus, expand treatment options for this large group of stroke patients.