Clinical importance of microbleeds in patients receiving IV thrombolysis

Subcortical hemorrhage caused by cerebral amyloid angiopathy compared with hypertensive hemorrhage

OBJECTIVES

Most published reports on lobular hemorrhage in cerebral amyloid angiopathy (CAA) include patients diagnosed only by imaging studies. This study analyzed patients with subcortical hemorrhage histologically diagnosed as CAA or non-CAA (hypertensive).

METHODS

This is a retrospective study analyzing data from 100 craniotomy cases. Tissue of hematoma cavity wall was collected for histological investigation in hematoma removal by surgery in patients with subcortical hemorrhage. Statistical analyses of blood pressure, hematoma location and volume, outcome, and mortality was performed in CAA and non-CAA groups.

RESULTS

There were 47 CAA and 53 non-CAA cases, and average age was significantly older in the CAA group (p < 0.01). Blood pressure was significantly lower (p < 0.01) but hematoma volume was significantly greater (p < 0.05) in the CAA group. Rebleeding occurred in two CAA cases and one non-CAA case, but no re-operations were required. Average score of modified Rankin Scale, which is used to measure the degree of disability in patients who have had a stroke, at three months after surgery was not significantly different between the two groups (CAA: 3.94 ± 1.28, non-CAA: 3.58 ± 1.50). There were seven deaths in the CAA and six in the non-CAA group, and intraventricular hemorrhage highly complicated in the death cases in both groups. In the CAA group, average age of the fatal cases was significantly older than that of the surviving cases (p < 0.05) and six cases demonstrated dementia before onset of hemorrhage.

CONCLUSIONS

Surgical removal of a subcortical hemorrhage caused by CAA is not contraindicated. However, age > 80 years, complication with intraventricular hemorrhage, hematoma volume ≥ 50 ml, and dementia before onset of hemorrhage contribute to high mortality, and craniotomy should be carefully considered for such patients. A limitation of this study is that comparison between CAA and non-CAA groups was performed in the patients with only surgically indicated ICH, and does not evaluate entire ICH cases with CAA. However, this study appropriately compared pathologically diagnosed CAA and non-CAA in patients with moderate to severe lobular ICH with surgical indications.

Prevalence and Impact of Cerebral Microbleeds on Clinical and Safety Outcomes in Acute Ischaemic Stroke Patients Receiving Reperfusion Therapy: A Systematic Review and Meta-Analysis

BACKGROUND

Cerebral microbleeds (CMBs), a notable neuroimaging finding often associated with cerebral microangiopathy, demonstrate a heightened prevalence in patients diagnosed with acute ischemic stroke (AIS), which is in turn linked to less favourable clinical prognoses. Nevertheless, the exact prevalence of CMBs and their influence on post-reperfusion therapy outcomes remain inadequately elucidated.

MATERIALS AND METHODS

Through systematic searches of PubMed, Embase and Cochrane databases, studies were identified adhering to specific inclusion criteria: (a) AIS patients, (b) age ≥ 18 years, (c) CMBs at baseline, (d) availability of comparative data between CMB-positive and CMB-negative groups, along with relevant post-reperfusion therapy outcomes. The data extracted were analysed using forest plots of odds ratios, and random-effects modelling was applied to investigate the association between CMBs and symptomatic intracerebral haemorrhage (sICH), haemorrhagic transformation (HT), 90-day functional outcomes, and 90-day mortality post-reperfusion therapy.

RESULTS

In a total cohort of 9776 AIS patients who underwent reperfusion therapy, 1709 had CMBs, with a pooled prevalence of 19% (ES 0.19; 95% CI: 0.16, 0.23, p < 0.001). CMBs significantly increased the odds of sICH (OR 2.57; 95% CI: 1.72; 3.83; p < 0.0001), HT (OR 1.53; 95% CI: 1.25; 1.88; p < 0.0001), as well as poor functional outcomes at 90 days (OR 1.59; 95% CI: 1.34; 1.89; p < 0.0001) and 90-day mortality (OR 1.65; 95% CI: 1.27; 2.16; p < 0.0001), relative to those without CMBs, in AIS patients undergoing reperfusion therapy (encompassing intravenous thrombolysis [IVT], endovascular thrombectomy [EVT], either IVT or EVT, and bridging therapy). Variations in the level of association can be observed among different subgroups of reperfusion therapy.

CONCLUSIONS

This meta-analysis underscores a significant association between CMBs and adverse postprocedural safety outcomes encompassing sICH, HT, poor functional outcome, and increased mortality in AIS patients undergoing reperfusion therapy. The notable prevalence of CMBs in both the overall AIS population and those undergoing reperfusion therapy emphasizes their importance in post-stroke prognostication.

Total Cerebral Small Vessel Disease Score and Cerebral Bleeding Risk in Patients With Acute Stroke Treated With Intravenous Thrombolysis

Objective

The aim of this study was to investigate the association of total cerebral small vessel disease (cSVD) score with the risk of intracerebral hemorrhage (ICH) in patients with acute ischemic stroke who received intravenous thrombolysis (IVT) using recombinant tissue-plasminogen activator (rt-PA).

Methods

We retrospectively reviewed clinical data from two stroke registries of patients with acute ischemic stroke treated with IVT. We assessed the baseline magnetic resonance (MR) visible cSVD markers and total cSVD score (ranging from 0 to 4) between patients with and without ICH after IVT. Logistic regression analysis was used to determine the association of total cSVD score with the risk of ICH after IVT, adjusted for cofounders selected by least absolute shrinkage and selection operator (LASSO). We additionally performed an E-value analysis to fully explain away a specific exposure-outcome association. Receiver operating characteristic (ROC) curve analysis was used to quantify the predictive potential of the total cSVD score for any ICH after IVT.

Results

Among 271 eligible patients, 55 (20.3%) patients experienced any ICH, 16 (5.9%) patients experienced a symptomatic ICH (sICH), and 5 (1.85%) patients had remote intracranial parenchymal hemorrhage (rPH). Logistic regression analysis showed that the risk of any ICH increased with increasing cSVD score [per unit increase, adjusted odds ratio (OR) 2.03, 95% CI 1.22–3.41, P = 0.007]. Sensitivity analyses using E-value revealed that it would need moderately robust unobserved confounding to render the exposure-outcome (cSVD-any ICH) association null. ROC analysis showed that compared with the National Institutes of Health Stroke Scale (NIHSS) score alone, a combination of cSVD and NIHSS score had a larger area under the curve for any ICH (0.811, 95% CI 0.756–0.866 vs. 0.784, 95% CI 0.723–0.846, P = 0.0004).

Conclusion

The total cSVD score is associated with an increased risk of any ICH after IVT and improves prediction for any ICH compared with NIHSS alone.

Neuroimaging Markers of Cerebral Small Vessel Disease on Hemorrhagic Transformation and Functional Outcome After Intravenous Thrombolysis in Patients With Acute Ischemic Stroke: A Systematic Review and Meta-Analysis

Objective: The aim of this study was to perform a systematic review and meta-analysis to assess whether cerebral small vessel disease (CSVD) on neuroimaging of patients with acute ischemic stroke (AIS) treated with intravenous thrombolysis (IVT) is associated with an increased risk of hemorrhagic transformation (HT), symptomatic intracranial hemorrhage (sICH), and poor functional outcome (PFO). Methods: A thorough search of several databases was carried out to identify relevant studies up to December 2020. We included studies of patients with AIS and neuroimaging markers of CSVD treated with IVT. The primary outcome was HT, and the secondary outcomes were sICH and 3-month PFO. The quality of the studies involved was evaluated using the Newcastle-Ottawa Scale (NOS). The meta-analysis with the fixed effects model was performed. Results: Twenty-four eligible studies (n = 9,419) were pooled in the meta-analysis. All included studies were regarded as high quality with the NOS scores of at least 6 points. The meta-analysis revealed associations between the presence of CSVD and HT, sICH, and the 3-month PFO after IVT. Compared with no CSVD, the presence of CSVD was associated with an increased risk of HT (OR: 1.81, 95% CI: 1.52-2.16), sICH (OR: 2.42, 95% CI: 1.76-3.33), and 3-month PFO (OR: 2.15, 95% CI: 1.89-2.44). For patients with AIS complicated with CSVD, compared with a CSVD score of 0-1, a CSVD score of 2-4 was associated with an increased risk of HT (OR: 3.10, 95% CI: 1.67-5.77), sICH (OR: 2.86, 95% CI: 1.26-6.49), and 3-month PFO (OR: 4.58, 95% CI: 2.97-7.06). Conclusion: Patients with AIS complicated with neuroimaging markers of CSVD are at increased risk of HT and 3-month PFO after IVT. However, it is still necessary to clarify the exact role of CSVD in the occurrence, development, and prognosis of AIS. Systematic Review Registration: www.ClinicalTrials.gov, identifier CRD4202123 3900.

Cerebral Microbleeds Detected Using 3.0T Magnetic Resonance Imaging in 2,003 Patients with Ischemic or Hemorrhagic Stroke

Introduction:

Compared with 1.5T magnetic resonance imaging (MRI), using 3.0T MRI makes it easier to detect cerebral microbleeds (CMBs). We used 3.0T MRI to investigate the backgrounds, risk factors, and number and location of CMBs in patients with ischemic or hemorrhagic stroke.

Methods:

We extracted data on clinical characteristics, risk factors, and number and location of CMBs in 2,003 patients treated between January 2010 and December 2014 within one week of stroke occurrence. We then carried out multivariate analysis of the data.

Results:

CMBs were present in 1,025 patients. The numbers of CMBs in ischemic stroke and hemorrhagic stroke patients were 9,410 and 6,419, respectively. Patients with CMBs showed significantly higher rates of cognitive impairment (p < 0.001, odds ratio [OR] = 1.514), hypertension (p < 0.001, OR = 3.145), previous history of stroke (p < 0.001, OR = 1.782), and presence of hemorrhagic stroke (p < 0.001, OR = 2.066). The use of antithrombotic medication before the stroke did not affect the incidence of CMBs. In ischemic stroke patients, patients with small vessel occlusion had a significantly greater rate of previous history of hemorrhagic stroke (p = 0.046) and number of patients with CMBs (p < 0.001) than those with cardioembolism.

Conclusions:

CMBs were well observed in patients with small vessel disease, and hypertension was an important factor in ischemic and hemorrhagic stroke. Antithrombotic medication is not associated with the development of CMBs if adequate antihypertensive therapy is provided.

Does High Cerebral Microbleed Burden Increase the Risk of Intracerebral Hemorrhage After Intravenous Tissue Plasminogen Activator for Acute Ischemic Stroke?

BACKGROUND

The risk of developing intracerebral hemorrhage (ICH) after the administration of intravenous tissue plasminogen activator for acute ischemic stroke is well established in the general population. However, the risk associated with stroke thrombolysis in patients with a history of cerebral microbleeds (CMBs) is undetermined.

OBJECTIVE

The main objective of this study was to critically assess current evidence with regard to the risk of development of ICH after the administration of intravenous tissue plasminogen activator for acute ischemic stroke in patients with CMBs.

METHODS

The objective was addressed through the development of a critically appraised topic that included a clinical scenario, structured question, literature search strategy, critical appraisal, assessment of results, evidence summary, commentary, and bottom-line conclusions. Participants included consultant and resident neurologists, a medical librarian, clinical epidemiologists, and content experts in the field of vascular and hospital neurology.

RESULTS

A recent individual patient data meta-analysis was selected for critical appraisal. Cohorts were analyzed with pretreatment magnetic resonance imaging to determine CMB burden and were followed-up to assess subsequent symptomatic ICH, hemorrhagic transformation, parenchymal hemorrhage (PH), and remote PH (PHr) following intravenous thrombolysis. Risk of symptomatic ICH, PH, and PHr was increased in the presence of CMBs, with PHr having the strongest association with increasing CMB burden. Only patients with >10 CMBs were found to have associations with poor outcome at 3 to 6 months, whereas there was no association with 3 to 6 months' mortality.

CONCLUSIONS

CMBs are associated with an increased risk of postthrombolysis ICH; however, the clinical implications have yet to be determined.

Pretreatment cerebral microbleeds and symptomatic intracerebral hemorrhage post-thrombolysis: a systematic review and meta-analysis

BACKGROUND AND PURPOSE

Cerebral microbleeds (CMBs) are a possible predictor of symptomatic intracranial hemorrhage (sICH) and poor function outcome (PFO). We aimed to investigate the presence of CMBs on increased incidence of sICH and PFO in acute ischemic stroke patients receiving intravenous thrombolysis (IVT) treatment.

METHODS

We searched PubMed, EMBASE, and Cochrane Library from 1 January 1997 to 13 May 2018, for relevant studies and calculated the pooled relative risk (RR) for the incidence of sICH and PFO in patients with CMBs versus those without after IVT.

RESULTS

We included 2407 participants from nine studies. The cumulative sICH incidence was higher in patients with CMBs (6%, 95% CI 4-8%) than that in patients without CMBs (4%, 95% CI 2-6%) with pooled RR 1.51 (95% CI, 1.04-2.21; P = 0.031). Four studies including 1550 patients reported data on 3- to 6-month PFO. The cumulative PFO incidence was higher in patients with CMBs (53%, 95% CI 47-59%) than that in patients without CMBs (41%, 95% CI 36-46%) with pooled RR 1.25 (95% CI 1.11-1.41; P = 0.000).

CONCLUSIONS

The pretreatment CMBs were associated with increased incidence of sICH and PFO in acute ischemic stroke patients receiving IVT. However, it was not convincing enough to set the presence of CMBs as contraindication to IVT.

Cerebral Microbleeds are an Independent Predictor of Hemorrhagic Transformation Following Intravenous Alteplase Administration in Acute Ischemic Stroke

BACKGROUND AND PURPOSE

Intravenous alteplase (rt-PA) increases the risk of hemorrhagic transformation of acute ischemic stroke. The objective of our study was to evaluate clinical, laboratory, and imaging predictors on forecasting the risk of hemorrhagic transformation following treatment with rt-PA. We also evaluated the factors associated with cerebral microbleeds that increase the risk of hemorrhagic transformation.

METHODS

Consecutive patients with acute ischemic stroke admitted between January 1, 2009 and December 31, 2013 were included in the study if they received IV rt-PA, had magnetic resonance imaging (MRI) of the brain on admission, and computed tomography or MRI of the brain at 24 (18-36) hours later to evaluate for the presence of hemorrhagic transformation. The clinical data, lipid levels, platelet count, MRI, and computed tomography images were retrospectively reviewed.

RESULTS

The study included 366 patients, with mean age 67 ± 15 years; 46% were women and 88% were white. The median National Institutes of Health Stroke Scale (NIHSS) score was 6 (interquartile range 3-15). Hemorrhagic transformation was observed in 87 (23.8%) patients and cerebral microbleeds were noted in 95 (25.9%). Patients with hemorrhagic transformation tended to be older, nonwhite, have atrial fibrillation, higher baseline NIHSS score, lower cholesterol and triglyceride levels, and cerebral microbleeds and nonlacunar infarcts. Patients with cerebral microbleeds were more likely to be older, have hypertension, hyperlipidemia, previous history of stroke, and prior use of antithrombotics. On multivariate analysis race, NIHSS score, nonlacunar infarct, and presence of cerebral microbleeds were independently associated with hemorrhagic transformation following treatment with rt-PA.

CONCLUSIONS

Presence of cerebral microbleeds is an independent predictor of hemorrhagic transformation of acute ischemic stroke following treatment with rt-PA.

Microbleeds, Cerebral Hemorrhage, and Functional Outcome After Stroke Thrombolysis

Background and Purpose—

We assessed whether the presence, number, and distribution of cerebral microbleeds (CMBs) on pre-intravenous thrombolysis MRI scans of acute ischemic stroke patients are associated with an increased risk of intracerebral hemorrhage (ICH) or poor functional outcome.

Methods—

We performed an individual patient data meta-analysis, including prospective and retrospective studies of acute ischemic stroke treated with intravenous tissue-type plasminogen activator. Using multilevel mixed-effects logistic regression, we investigated associations of pre-treatment CMB presence, burden (1, 2–4, ≥5, and >10), and presumed pathogenesis (cerebral amyloid angiopathy defined as strictly lobar CMBs and noncerebral amyloid angiopathy) with symptomatic ICH, parenchymal hematoma (within [parenchymal hemorrhage, PH] and remote from the ischemic area [remote parenchymal hemorrhage, PHr]), and poor 3- to 6-month functional outcome (modified Rankin score >2).

Results—

In 1973 patients from 8 centers, the crude prevalence of CMBs was 526 of 1973 (26.7%). A total of 77 of 1973 (3.9%) patients experienced symptomatic ICH, 210 of 1806 (11.6%) experienced PH, and 56 of 1720 (3.3%) experienced PHr. In adjusted analyses, patients with CMBs (compared with those without CMBs) had increased risk of PH (odds ratio: 1.50; 95% confidence interval: 1.09–2.07; P =0.013) and PHr (odds ratio: 3.04; 95% confidence interval: 1.73–5.35; P <0.001) but not symptomatic ICH. Both cerebral amyloid angiopathy and noncerebral amyloid angiopathy patterns of CMBs were associated with PH and PHr. Increasing CMB burden category was associated with the risk of symptomatic ICH ( P =0.014), PH ( P =0.013), and PHr ( P <0.00001). Five or more and >10 CMBs independently predicted poor 3- to 6-month outcome (odds ratio: 1.85; 95% confidence interval: 1.10–3.12; P =0.020; and odds ratio: 3.99; 95% confidence interval: 1.55–10.22; P =0.004, respectively).

Conclusions—

Increasing CMB burden is associated with increased risk of ICH (including PHr) and poor 3- to 6-month functional outcome after intravenous thrombolysis for acute ischemic stroke.

Prevention of Stroke in Patients With Silent Cerebrovascular Disease: A Scientific Statement for Healthcare Professionals From the American Heart Association/American Stroke Association

Two decades of epidemiological research shows that silent cerebrovascular disease is common and is associated with future risk for stroke and dementia. It is the most common incidental finding on brain scans. To summarize evidence on the diagnosis and management of silent cerebrovascular disease to prevent stroke, the Stroke Council of the American Heart Association convened a writing committee to evaluate existing evidence, to discuss clinical considerations, and to offer suggestions for future research on stroke prevention in patients with 3 cardinal manifestations of silent cerebrovascular disease: silent brain infarcts, magnetic resonance imaging white matter hyperintensities of presumed vascular origin, and cerebral microbleeds. The writing committee found strong evidence that silent cerebrovascular disease is a common problem of aging and that silent brain infarcts and white matter hyperintensities are associated with future symptomatic stroke risk independently of other vascular risk factors. In patients with cerebral microbleeds, there was evidence of a modestly increased risk of symptomatic intracranial hemorrhage in patients treated with thrombolysis for acute ischemic stroke but little prospective evidence on the risk of symptomatic hemorrhage in patients on anticoagulation. There were no randomized controlled trials targeted specifically to participants with silent cerebrovascular disease to prevent stroke. Primary stroke prevention is indicated in patients with silent brain infarcts, white matter hyperintensities, or microbleeds. Adoption of standard terms and definitions for silent cerebrovascular disease, as provided by prior American Heart Association/American Stroke Association statements and by a consensus group, may facilitate diagnosis and communication of findings from radiologists to clinicians.

Cerebral microbleeds and postthrombolysis intracerebral hemorrhage risk Updated meta-analysis

OBJECTIVE

We performed a systematic review and meta-analysis to assess whether the presence of cerebral microbleeds (CMBs) on pretreatment MRI scans of patients with acute ischemic stroke treated with thrombolysis is associated with an increased risk of symptomatic intracerebral hemorrhage (ICH).

METHODS

We searched PubMed for relevant studies and calculated pooled odds ratios (ORs) for symptomatic ICH, using the Mantel–Haenszel fixed-effects method, among individuals with vs without CMBs on pretreatment MRI scans. To minimize potential bias, sensitivity analysis was performed including studies providing data on patients treated only with IV thrombolysis.

RESULTS

Ten eligible studies including 2,028 patients were pooled in meta-analysis. The overall prevalence of CMBs was 23.3%. Among patients with CMBs, 40 of 472 (8.5%; 95%confidence interval [CI]: 6.1%–11.4%) experienced a symptomatic ICH after thrombolysis compared with 61 of 1,556 patients (3.9%; 95% CI: 3%–5%) without CMBs. The pooled OR of ICH across all studies was 2.26 (95%CI: 1.46–3.49; p , 0.0001). Eight studies, including 1,704 patients (n 5 401 with CMBs), provided data on patients treated with IV thrombolysis only; OR for the presence of CMBs and the development of symptomatic ICH was 2.87 (95%CI: 1.76–4.69; p , 0.0001).

CONCLUSIONS

Our meta-analysis of the available published data demonstrates an increased risk of symptomatic ICH after thrombolysis for acute ischemic stroke in patients with CMBs. However, we cannot fully exclude bias or confounding, so our results should be considered hypothesis generating. Detecting CMBs should not prevent thrombolytic treatment based on present evidence. Further analyses, taking into account CMB number and location, as well as measures of functional outcome, are needed.

Clinical Outcome in Acute Ischemic Stroke Patients With Microbleeds After Thrombolytic Therapy: A Meta-Analysis

It remains unclear whether preexisting cerebral microbleeds (CMBs) increase the risks of worse functional outcome after thrombolytic therapy. We performed a systematic review and meta-analysis to assess the risk of unfavorable outcome in patients with acute ischemic stroke and CMBs.We searched EMBASE, PubMed, and Web of Science for relevant studies assessing functional outcome in the patients with CMBs following thrombolytic therapy. Fixed-effects and random-effects models were performed.Five eligible studies including 1974 patients were pooled in meta-analysis. The prevalence of CMBs was 24.3%. The pooled analysis demonstrates odds ratio for preexisting CMBs and the achievement of favorable outcome to be 0.69 (95% CI 0.56-0.86; P = 0.001) with no evidence of statistical heterogeneity (I = 46.7%, P = 0.112).Our meta-analysis of available published data demonstrates an increased risk of worse functional outcome after thrombolytic therapy for acute ischemic stroke in patients with pre-existing CMBs. Future studies are needed to determine whether the risk outweigh the expected benefit of reperfusion therapies.

Extensive cerebral microbleeds predict parenchymal haemorrhage and poor outcome after intravenous thrombolysis

PURPOSE

Thrombolysis-related haemorrhagic transformation (HT) subtypes may have different prognostic implications. We aimed to analyse the impact of cerebral microbleeds (CMBs) burden on HT subtypes and outcome after intravenous thrombolysis.

METHODS

We retrospectively examined clinical and radiological data from 333 consecutive patients with acute ischaemic stroke who underwent susceptibility-weighted imaging before intravenous thrombolysis. Logistic regression analysis was used to determine the impact of CMBs on HT subtypes and neurological outcome.

RESULTS

We observed 596 CMBs in 119 (39.7%) patients on initial gradient-recalled echo scans. HT occurred in 88 (29.3%) patients, among which 62 were haemorrhagic infarction and 26 were parenchymal haemorrhage (PH). Logistic regression analysis indicated that the presence of extensive (≥ 3) CMBs was independently associated with PH (OR 6.704; 95% CI 2.054 to 21.883; p = 0.002) and poor clinical outcome (OR 2.281; 95% CI 1.022 to 5.093; p = 0.044).

CONCLUSIONS

The presence of extensive (≥ 3) CMBs increased the risk of PH 24 h after intravenous thrombolysis, and predicted poor clinical outcome independently.

Silent New Brain Lesions: Innocent Bystander or Guilty Party?

With the advances in magnetic resonance imaging, previously unrecognized small brain lesions, which are mostly asymptomatic, have been increasingly detected. Diffusion-weighted imaging can identify small ischemic strokes, while gradient echo T2* imaging and susceptibility-weighted imaging can reveal tiny hemorrhagic strokes (microbleeds). In this article, we review silent brain lesions appearing soon after acute stroke events, including silent new ischemic lesions and microbleeds appearing 1) after acute ischemic stroke and 2) after acute intracerebral hemorrhage. Moreover, we briefly discuss the clinical implications of these silent new brain lesions.

Multimodal Diagnostic Imaging for Hyperacute Stroke

In April 2015, the American Roentgen Ray Society and the American Society of Neuroradiology cosponsored a unique program designed to evaluate the state of the art in the imaging work-up of acute stroke. This topic has grown in importance because of the recent randomized controlled trials demonstrating the clear efficacy of endovascular stroke treatment. The authors, who were participants in that symposium, will highlight the points of emphasis in this article.

Microbleed Status and 3-Month Outcome After Intravenous Thrombolysis in 717 Patients With Acute Ischemic Stroke

Background and Purpose—

Whether cerebral microbleeds (CMBs) detected on pretreatment magnetic resonance imaging increase the risks of symptomatic intracranial hemorrhage (sICH) and, most importantly, poor outcome in patients treated by intravenous thrombolysis for acute ischemic stroke is still debated. We assessed the effect of CMB presence and burden on 3-month modified Rankin Scale and sICH in a multicentric cohort.

Methods—

We analyzed prospectively collected data of consecutive patients solely treated by intravenous thrombolysis for acute ischemic stroke, in 2 centers where magnetic resonance imaging is the first-line pretreatment imaging. Neuroradiologists blinded to clinical data rated CMBs on T2* sequence using a validated scale. Logistic regressions were used to assess relationships between CMBs and 3-month modified Rankin Scale or sICH.

Results—

Among 717 patients, 150 (20.9%) had ≥1 CMBs. CMB burden was associated with worse modified Rankin Scale in univariable shift analysis (odds ratio, 1.07; 95% confidence interval, 1.00–1.15 per 1-CMB increase; P =0.049), but significance was lost after adjustment for age, hypertension, and atrial fibrillation (odds ratio, 1.03; 95% confidence interval, 0.96–1.11 per 1-CMB increase; P =0.37). Results remained nonsignificant when taking into account CMB location or presumed underlying vasculopathy. The incidence of sICH ranged from 3.8% to 9.1%, depending on the definition. Neither CMB presence, burden, location, nor presumed underlying vasculopathy was independently associated with sICH.

Conclusions—

Poor outcome or sICH was not associated with CMB presence or burden on pre–intravenous thrombolysis magnetic resonance imaging after adjustment for confounding factors. An individual patient data meta-analysis is needed to determine whether a subgroup of patients with CMBs carries an independent risk of poor outcome that might outweigh the expected benefit of intravenous thrombolysis.

[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.

Prognostic Impact of Cerebral Small Vessel Disease on Stroke Outcome

Cerebral small vessel disease (SVD), which includes white matter hyperintensities (WMHs), silent brain infarction (SBI), and cerebral microbleeds (CMBs), develops in a conjunction of cumulated injuries to cerebral microvascular beds, increased permeability of blood-brain barriers, and chronic oligemia. SVD is easily detected by routine neuroimaging modalities such as brain computed tomography or magnetic resonance imaging. Research has revealed that the presence of SVD markers may increase the risk of future vascular events as well as deteriorate functional recovery and neurocognitive trajectories after stroke, and such an association could also be applied to hemorrhagic stroke survivors. Currently, the specific mechanistic processes leading to the development and manifestation of SVD risk factors are unknown, and further studies with novel methodological tools are warranted. In this review, recent studies regarding the prognostic impact of WMHs, SBI, and CMBs on stroke survivors and briefly summarize the pathophysiological concepts underlying the manifestation of cerebral SVD.

Imaging Patterns and Management Algorithms in Acute Stroke: An Update for the Emergency Radiologist

Neuroimaging plays a key role in the initial work-up of patients with symptoms of acute stroke. Understanding the advantages and limitations of available CT and MR imaging techniques and how to use them optimally in the emergency setting is crucial for accurately making the diagnosis of acute stroke and for rapidly determining appropriate treatment.

MRI-guided selection of patients for treatment of acute ischemic stroke

PURPOSE OF REVIEW

To summarize what is known about the use of MRI in acute stroke treatment (predominantly thrombolysis), to examine the assumptions and theories behind the interpretation of magnetic resonance images of acute ischemic stroke and how they are used to select patients for therapies, and to suggest directions for future research.

RECENT FINDINGS

Recent studies have been contradictory about the usefulness of MRI in selecting patients for treatment. New MRI models for selecting patients have emerged that focus not only on the ischemic penumbra but also on the infarct core. Fixed time-window selection parameters are being replaced by timing-based individualized MRI stroke features. New ways to interpret traditional MRI stroke sequences are emerging.

SUMMARY

Although the efficacy of acute stroke treatment is time dependent, the use of fixed time windows cannot account for individual differences in infarct evolution, which could potentially be detected with MRI. Although MRI shows promise for identifying patients who should be treated, as well as excluding patients who should not be treated, definitive evidence is still lacking. Future research should focus on validating the use of MRI to select patients for intravenous therapies in extended time windows.

Acute Stroke Imaging Part I: Fundamentals

Neuroimaging is essential to stroke diagnosis and management. To date, the non-contrast CT has served as our main diagnostic tool. Although brain parenchymal changes visible on CT do provide valuable prognostic information, they provide limited insight into the potential for tissue salvage in response to reperfusion therapy, such as thrombolysis. Newer advanced CT and MRI based imaging techniques have increased the detection sensitivity for hyperacute and chronic parenchymal changes, including ischemia and hemorrhage, permit visualization of blood vessels and cerebral blood flow. This review outlines the basic principles underlying acquisition and interpretation of these newer imaging modalities in the setting of acute stroke. The utility of advanced brain parenchymal and blood flow imaging in the context of acute stroke patient management is also discussed. Part II in this series is a discussion of how these techniques can be used to rationally select appropriate patients for thrombolysis based on pathophysiological data.

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.

The role of imaging in acute ischemic stroke

Neuroimaging has expanded beyond its traditional diagnostic role and become a critical tool in the evaluation and management of stroke. The objectives of imaging include prompt accurate diagnosis, treatment triage, prognosis prediction, and secondary preventative precautions. While capitalizing on the latest treatment options and expanding upon the "time is brain" doctrine, the ultimate goal of imaging is to maximize the number of treated patients and improve the outcome of one the most costly and morbid disease. A broad overview of comprehensive multimodal stroke imaging is presented here to affirm its utilization.

Influence of cognitive impairment on the management of ischaemic stroke

BACKGROUND

Because of ageing of the population, it is more and more frequent to treat ischaemic stroke patients with pre-stroke cognitive impairment (PSCI). Currently, there is no specific recommendation on ischaemic stroke management in these patients, both at the acute stage and in secondary prevention. However, these patients are less likely to receive treatments proven effective in randomised controlled trials, even in the absence of contra-indication.

OBJECTIVE

To review the literature to assess efficacy and safety of validated therapies for acute ischaemic stroke and secondary prevention in PSCI patients.

RESULTS

Most randomised trials did not take into account the pre-stroke cognitive status. The few observational studies conducted at the acute stage or in secondary prevention, did not provide any information that the benefit could be either lost or replaced by harm in the presence of PSCI.

CONCLUSIONS

There is no reason not to treat ischaemic stroke patients with PSCI according to the currently available recommendations for acute management and secondary prevention. Further observational studies are needed and pre-stroke cognition should be taken into account in future stroke trials.

Thrombolysis in acute stroke patients with cerebral small vessel disease

BACKGROUND

Thrombolytic treatment is of proven benefit in acute ischemic stroke. The term cerebral small vessel disease (SVD) refers to a group of pathological processes affecting the small arteries, arterioles, venules and capillaries of the brain, and encompasses both ischemic and hemorrhagic lesions. Lacunar stroke, an expression of SVD, is associated with an unfavorable long-term prognosis for an increased risk of death, recurrent stroke and cognitive dysfunction. Nonetheless, the efficacy and safety of intravenous thrombolysis in patients with lacunar stroke has been debated for two main reasons. First, among all ischemic stroke subtypes, lacunar strokes have been considered the most benign. Second, the efficacy of a pharmacological reperfusion has been questioned given the absence of a clear demonstration of thrombosis. Intracerebral hemorrhage (ICH) remains the most devastating and unpredictable complication related to thrombolysis, and neuroimaging evidence of SVD is nowadays recognized as one of the risk factors for thrombolysis-related ICH.

SUMMARY

This review is structured in two parts dealing with the questions whether or not patients with lacunar stroke or SVD should be treated with thrombolysis. In the first part, we revised the literature concerning the efficacy of thrombolysis in patients with acute lacunar stroke. We included two types of studies: those in which patients with lacunar stroke receiving recombinant human tissue plasminogen activator (rt-PA) were compared with lacunar stroke patients receiving placebo, and those in which a comparison was made among different stroke subtype patients treated with rt-PA. In the second part, we reviewed the available evidence on the risk of ICH in patients treated with thrombolysis for ischemic stroke and presenting with neuroimaging evidence of SVD such as white matter lesions (WML) and cerebral microbleeds. We further questioned the extent to which WML and microbleeds could be used as reliable predictors of ICH and the feasibility of their detection in an acute setting.

KEY MESSAGES

The studies herein reviewed show that thrombolysis is an effective treatment in acute lacunar stroke, and that the presence of cerebral SVD increases the risk of ICH during thrombolysis but does not represent an absolute exclusion criterion. In the future, it can be assumed that the use of MRI on a routine basis might lead to a better quantitative definition of SVD and its correlates, permitting a step forward in thrombolysis decision making.

Hyperacute management of ischemic stroke

Stroke is a devastating disease and currently the fourth leading cause of death in this country. Acute ischemic stroke is an emergency and requires effective triage, diagnosis, and critical management. The hyperacute management of ischemic stroke begins in the field, with recognition of stroke symptoms by emergency medical systems (EMS) personnel. The EMS is an important component to an effective stroke system of care, which also includes primary stroke centers, routing protocols for acute ischemic stroke, and telemedicine. Following the arrival of a potential stroke patient to the emergency room setting, patients should be stabilized and undergo assessment for potential intravenous alteplase (IV tPA) treatment. Assessments include diagnostic tests, neuroimaging, and standardized stroke evaluations. After these assessments have been performed, IV tPA, the only medication for acute stroke approved by the U.S. Food and Drug Administration, can be considered using a variety of inclusion and exclusion criteria. Previously time restrictions limited the usage of IV tPA to 3 hours, but this time window has now been extended for eligible candidates to 4.5 hours. The administration of IV tPA has specific requirements for monitoring and should be standardized via protocol across hospitals.

New Appearance of Extraischemic Microbleeds on T2*-Weighted Magnetic Resonance Imaging 24 Hours After Tissue-type Plasminogen Activator Administration

Background and Purpose—

It is unknown whether new-extraischemic microbleeds (new-EMBs) develop rapidly after tissue-type plasminogen activator (tPA) infusion. We hypothesized that new-EMBs may develop rapidly after tPA infusion using T2*-weighted MRI (T2*) and investigated the frequency and clinical factors associated with new-EMBs.

Methods—

Patients with acute stroke within 3 hours of onset who were treated with tissue-type plasminogen activator (tPA) were studied prospectively. T2* was performed before and 24 hours after tPA therapy. Independent clinical factors associated with new-EMBs development were examined using multivariate logistic regression analysis.

Results—

A total of 224 patients (121 men; mean age, 76.2±10.6 years) were enrolled in the present study. MBs before tPA infusion were observed in 72 (32.1%) patients. Within 24 hours after tPA infusion, 6 (2.7%) patients had symptomatic intracranial hemorrhage (extraischemic [n=4], and hemorrhagic transformation [n=2]). Follow-up T2* revealed asymptomatic new-EMBs in 11 (4.9%) patients and hemorrhagic transformation in the infarcted area in 65 (29.0%). The total and mean number of new-EMBs were 23 and 1.6±1.3, respectively. Patients with new-EMBs more frequently had symptomatic extraischemic hemorrhage than those without new-EMBs (27.3% [3/11] versus 0.5% [1/213]; P =0.0003). However, the frequency of hemorrhagic transformation was not different between patients with and without new-EMBs (27.3% versus 29.1%; P =0.9999). Multivariate logistic regression demonstrated that the presence of MBs before tPA infusion was the only independent factor associated with new-EMBs (odds ratio, 10.6; 95% confidence interval, 20.68–54.279; P =0.0046).

Conclusions—

New-EMBs occurred rapidly after tPA infusion in 4.9% of patients. The presence of MBs before tPA therapy was associated with new-EMBs. Patients with new-EMBs are likely to have symptomatic extraischemic hemorrhage.

Cerebral microbleeds: their associated factors, radiologic findings, and clinical implications

Cerebral microbleeds (CMBs) are tiny, round dark-signal lesions that are most often detected on gradient-echo MR images. CMBs consist of extravasations of blood components through fragile microvascular walls characterized by lipohyalinosis and surrounding macrophages. The prevalence of CMBs in elderly subjects with no history of cerebrovascular disease is around 5%, but is much higher in patients with ischemic or hemorrhagic stroke. Development of CMBs is closely related to various vascular risk factors; in particular, lobar CMBs are thought to be associated with cerebral amyloid angiopathy. The presence of CMBs has been hypothesized to reflect cerebral-hemorrhage-prone status in patients with hypertension or amyloid microangiopathy. Stroke survivors with CMBs have been consistently found to have an elevated risk of subsequent hemorrhagic stroke or an antithrombotic-related hemorrhagic complication, although studies have failed to establish a link between CMBs and hemorrhagic transformation after thrombolytic treatment. A large prospective study is required to clarify the clinical significance of CMBs and their utility in a decision-making index.

Imaging recommendations for acute stroke and transient ischemic attack patients: A joint statement by the American Society of Neuroradiology, the American College of Radiology, and the Society of NeuroInterventional Surgery

SUMMARY

Stroke is a leading cause of death and disability worldwide. Imaging plays a critical role in evaluating patients suspected of acute stroke and transient ischemic attack, especially before initiating treatment. Over the past few decades, major advances have occurred in stroke imaging and treatment, including Food and Drug Administration approval of recanalization therapies for the treatment of acute ischemic stroke. A wide variety of imaging techniques has become available to assess vascular lesions and brain tissue status in acute stroke patients. However, the practical challenge for physicians is to understand the multiple facets of these imaging techniques, including which imaging techniques to implement and how to optimally use them, given available resources at their local institution. Important considerations include constraints of time, cost, access to imaging modalities, preferences of treating physicians, availability of expertise, and availability of endovascular therapy. The choice of which imaging techniques to employ is impacted by both the time urgency for evaluation of patients and the complexity of the literature on acute stroke imaging. Ideally, imaging algorithms should incorporate techniques that provide optimal benefit for improved patient outcomes without delaying treatment.

Imaging and treatment of patients with acute stroke: an evidence-based review

Evidence-based medicine has emerged as a valuable tool to guide clinical decision-making, by summarizing the best possible evidence for both diagnostic and treatment strategies. Imaging plays a critical role in the evaluation and treatment of patients with acute ischemic stroke, especially those who are being considered for thrombolytic or endovascular therapy. Time from stroke-symptom onset to treatment is a strong predictor of long-term functional outcome after stroke. Therefore, imaging and treatment decisions must occur rapidly in this setting, while minimizing unnecessary delays in treatment. The aim of this review was to summarize the best available evidence for the diagnostic and therapeutic management of patients with acute ischemic stroke.

Cerebral microbleeds and the risk of intracerebral haemorrhage after thrombolysis for acute ischaemic stroke: systematic review and meta-analysis

BACKGROUND

Intracerebral haemorrhage (ICH) remains the most devastating yet unpredictable complication of intravenous thrombolysis for acute ischaemic stroke. We performed a systematic review and meta-analysis, to assess whether the presence of cerebral microbleeds (CMBs) on prethrombolysis MRI scans is associated with an increased risk of ICH.

METHODS

We searched PubMed for studies assessing ICH risk in patients with acute ischaemic stroke treated with thrombolysis, in relation to the presence of pre-treatment CMBs.

RESULTS

We identified five studies including 790 patients and pooled data in a meta-analysis. The CMB (+) versus CMB (-) groups were not significantly different in age, gender or stroke severity. The overall prevalence of CMBs was 135/790 (17.1%). Amongst patients with CMBs, 10/135 (7.4%) experienced a symptomatic ICH after thrombolysis, compared to 29/655 (4.4%) patients without CMBs. The pooled relative risk of ICH was 1.90 (95% CI 0.92 to 3.93; p=0.082).

CONCLUSIONS

The available evidence does not demonstrate a statistically significant increased risk of symptomatic ICH after thrombolysis for ischaemic stroke in patients with CMBs. However, in view of the methodological limitations of the studies included, the clinical relevance of any potential hazard associated with CMBs remains uncertain. Further studies are warranted to evaluate whether the risk of ICH might outweigh the benefit of thrombolysis, especially in patients with multiple lobar CMBs suggestive of cerebral amyloid angiopathy.

Guidelines for the early management of patients with acute ischemic stroke: a guideline for healthcare professionals from the American Heart Association/American Stroke Association

BACKGROUND AND PURPOSE

The authors present an overview of the current evidence and management recommendations for evaluation and treatment of adults with acute ischemic stroke. The intended audiences are prehospital care providers, physicians, allied health professionals, and hospital administrators responsible for the care of acute ischemic stroke patients within the first 48 hours from stroke onset. These guidelines supersede the prior 2007 guidelines and 2009 updates.

METHODS

Members of the writing committee were appointed by the American Stroke Association Stroke Council's Scientific Statement Oversight Committee, representing various areas of medical expertise. Strict adherence to the American Heart Association conflict of interest policy was maintained throughout the consensus process. Panel members were assigned topics relevant to their areas of expertise, reviewed the stroke literature with emphasis on publications since the prior guidelines, and drafted recommendations in accordance with the American Heart Association Stroke Council's Level of Evidence grading algorithm.

RESULTS

The goal of these guidelines is to limit the morbidity and mortality associated with stroke. The guidelines support the overarching concept of stroke systems of care and detail aspects of stroke care from patient recognition; emergency medical services activation, transport, and triage; through the initial hours in the emergency department and stroke unit. The guideline discusses early stroke evaluation and general medical care, as well as ischemic stroke, specific interventions such as reperfusion strategies, and general physiological optimization for cerebral resuscitation.

CONCLUSIONS

Because many of the recommendations are based on limited data, additional research on treatment of acute ischemic stroke remains urgently needed.

Cerebral microbleeds: a new dilemma in stroke medicine

Cerebral microbleeds (CMBs) are an increasingly common neuroimaging finding in the context of ageing, cerebrovascular disease and dementia, with potentially important clinical relevance. Perhaps the most pressing clinical question is whether CMBs are associated with a clinically important increase in the risk of intracerebral haemorrhage (ICH), the most feared complication in patients treated with thrombolytic or antithrombotic (antiplatelet and anticoagulant) drugs. This review will summarize the evidence available regarding CMBs as an indicator of future ICH risk in stroke medicine clinical practice.

Postthrombolysis intracranial hemorrhage risk of cerebral microbleeds in acute stroke patients: a systematic review and meta-analysis

It has been questioned whether patients with cerebral microbleeds are at a greater risk for the development of symptomatic intracerebral hemorrhage following thrombolytic therapy in the management of acute ischemic stroke. Thus far, observational studies have not shown a statistically significant increased risk; however, these have been limited by small sample size. The aim is to better quantify the risk of postthrombolysis intracerebral hemorrhage in patients with acute ischemic stroke and cerebral microbleeds on magnetic resonance imaging. A systematic review of controlled studies investigating the presence of microbleeds on magnetic resonance imaging as a risk factor for intracerebral hemorrhage following thrombolysis in acute stroke patients was conducted. A random effects model meta-analysis was performed. In pooled analysis of five studies totaling 790 participants, the prevalence of microbleeds was 17%. The presence of microbleeds revealed a trend toward an increased risk of postthrombolysis symptomatic intracerebral hemorrhage [odds ratio: 1·98 (95% confidence interval, 0·90 to 4·35; P = 0·09), I(2)  = 0%]. Adjusted analysis minimizing potential bias resulted in an increased absolute risk of 4·6% for the development of symptomatic intracerebral hemorrhage in patients with cerebral microbleeds [odds ratio: 2·29 (95% confidence interval, 1·01 to 5·17), I(2)  = 0%] reaching borderline significance (P = 0·05). A significant relationship between increasing microbleed burden and symptomatic intracerebral hemorrhage (P = 0·0015) was observed. Isolated analysis of studies using exclusively intravenous tissue plasminogen activator was insignificant. Our data suggest that patients with cerebral microbleeds are at increased risk for symptomatic intracerebral hemorrhage following thrombolysis for acute ischemic stroke. However, current data are insufficient to justify withholding thrombolytic therapy from acute ischemic stroke patients solely of the basis of cerebral microbleed presence.