Indications for thrombectomy in acute ischemic stroke from emergent large vessel occlusion (ELVO): report of the SNIS Standards and Guidelines Committee

Blood Pressure Management Following Acute Ischemic Stroke: A Review of Primary Literature

Elevated blood pressure is common in patients with acute ischemic stroke. While this may occur secondary to the body's own response to preserve cerebral blood flow, elevated blood pressure may also increase the risk of hemorrhagic transformation. Current guidelines recommend various blood pressure goals based upon multiple factors, including thresholds specific to certain treatment interventions. Despite these guidelines, there is limited evidence to support specific blood pressure targets, and variability in clinical practice is common. The purpose of this review was to discuss blood pressure management in adult patients with acute ischemic stroke, focusing on appropriate targets in the setting of alteplase administration, mechanical thrombectomy, and hemorrhagic transformation.

DWI-Based Algorithm to Predict Disability in Patients Treated with Thrombectomy for Acute Stroke

BACKGROUND AND PURPOSE

The reasons for poor clinical outcome after thrombectomy for acute stroke, concerning around half of all patients, are misunderstood. We developed a hierarchic algorithm based on DWI to better identify patients at high risk of disability.

MATERIALS AND METHODS

Our single-center, retrospective study included consecutive patients with acute ischemic stroke who underwent thrombectomy for large anterior artery occlusion and underwent pretreatment DWI. The primary outcome was the mRS at 3 months after stroke onset. Multivariable regression was used to identify independent clinical and imaging predictors of poor prognosis (mRS > 2) at 3 months, and a hierarchic algorithm predictive of disability was developed.

RESULTS

A total of 149 patients were analyzed. In decreasing importance, DWI lesion volume of >80 mL, baseline NIHSS score of >14, age older than 75 years, and time from stroke onset to groin puncture of >4 hours were independent predictors of poor prognosis. The predictive hierarchic algorithm developed from the multivariate analysis predicted the risk of disability at 3 months for up to 100% of patients with a high predictive value. The area under the receiver operating characteristic curve was 0.87.

CONCLUSIONS

The DWI-based hierarchic algorithm we developed is highly predictive of disability at 3 months after thrombectomy and is easy to use in routine practice.

Assessment of a Bayesian Vitrea CT Perfusion Analysis to Predict Final Infarct and Penumbra Volumes in Patients with Acute Ischemic Stroke: A Comparison with RAPID

BACKGROUND AND PURPOSE

Brain CTP is used to estimate infarct and penumbra volumes to determine endovascular treatment eligibility for patients with acute ischemic stroke. We aimed to assess the accuracy of a Bayesian CTP algorithm in determining penumbra and final infarct volumes.

MATERIALS AND METHODS

Data were retrospectively collected for 105 patients with acute ischemic stroke (55 patients with successful recanalization [TICI 2b/2c/3] and large-vessel occlusions and 50 patients without interventions). Final infarct volumes were calculated using DWI and FLAIR 24 hours following CTP imaging. RAPID and the Vitrea Bayesian CTP algorithm (with 3 different settings) predicted infarct and penumbra volumes for comparison with final infarct volumes to assess software performance. Vitrea settings used different combinations of perfusion maps (MTT, TTP, CBV, CBF, delay time) for infarct and penumbra quantification. Patients with and without interventions were included for assessment of predicted infarct and penumbra volumes, respectively.

RESULTS

RAPID and Vitrea default setting had the most accurate final infarct volume prediction in patients with interventions ([Spearman correlation coefficient, mean infarct difference] default versus FLAIR: [0.77, 4.1 mL], default versus DWI: [0.72, 4.7 mL], RAPID versus FLAIR: [0.75, 7.5 mL], RAPID versus DWI: [0.75, 6.9 mL]). Default Vitrea and RAPID were the most and least accurate in determining final infarct volume for patients without an intervention, respectively (default versus FLAIR: [0.76, -0.4 mL], default versus DWI: [0.71, -2.6 mL], RAPID versus FLAIR: [0.68, -49.3 mL], RAPID versus DWI: [0.65, -51.5 mL]).

CONCLUSIONS

Compared with RAPID, the Vitrea default setting was noninferior for patients with interventions and superior in penumbra estimation for patients without interventions as indicated by mean infarct differences and correlations with final infarct volumes.

Quantifying the Impact of Chronic Ischemic Injury on Clinical Outcomes in Acute Stroke With Machine Learning

Acute stroke is often superimposed on chronic damage from previous cerebrovascular events. This background will inevitably modulate the impact of acute injury on clinical outcomes to an extent that will depend on the precise anatomical pattern of damage. Previous attempts to quantify such modulation have employed only reductive models that ignore anatomical detail. The combination of automated image processing, large-scale data, and machine learning now enables us to quantify the impact of this with high-dimensional multivariate models sensitive to individual variations in the detailed anatomical pattern. We introduce and validate a new automated chronic lesion segmentation routine for use with non-contrast CT brain scans, combining non-parametric outlier-detection score, Zeta, with an unsupervised 3-dimensional maximum-flow, minimum-cut algorithm. The routine was then applied to a dataset of 1,704 stroke patient scans, obtained at their presentation to a hyper-acute stroke unit (St George's Hospital, London, UK), and used to train a support vector machine (SVM) model to predict between low (0-2) and high (3-6) pre-admission and discharge modified Rankin Scale (mRS) scores, quantifying performance by the area under the receiver operating curve (AUROC). In this single center retrospective observational study, our SVM models were able to differentiate between low (0-2) and high (3-6) pre-admission and discharge mRS scores with an AUROC of 0.77 (95% confidence interval of 0.74-0.79), and 0.76 (0.74-0.78), respectively. The chronic lesion segmentation routine achieved a mean (standard deviation) sensitivity, specificity and Dice similarity coefficient of 0.746 (0.069), 0.999 (0.001), and 0.717 (0.091), respectively. We have demonstrated that machine learning models capable of capturing the high-dimensional features of chronic injuries are able to stratify patients-at the time of presentation-by pre-admission and discharge mRS scores. Our fully automated chronic stroke lesion segmentation routine simplifies this process, and utilizes routinely collected CT head scans, thereby facilitating future large-scale studies to develop supportive clinical decision tools.

Smart diagnostic nano-agents for cerebral ischemia

A summary of the latest developments on imaging techniques and smart nano-diagnostics used for ischemic stroke.

Large Vessel Occlusion in the Acute Stroke Patient: Identification, Treatment, and Management

Acute ischemic stroke is a major cause of death and disability in the United States. Historically, acute stroke patients were treated with intravenous (IV) thrombolysis. Patients with large vessel occlusions (LVOs) should be offered mechanical thrombectomy, with or without IV thrombolysis, in an extended window up to 24 hours of last known well. Both treatment options are the standard of care for a patient with an LVO. It is critical that the intensive care unit nurse understand new treatment indications for LVO strokes, and the priorities of nursing care with medical and endovascular intervention.

Endovascular Treatment of Acute Ischemic Stroke

PURPOSE OF REVIEW

Endovascular thrombectomy (ET), the standard of treatment for emergent large vessel occlusion (ELVO) strokes, has been subject to rigorous efforts to further improve its usage and delivery for optimised patient outcomes. This review aims to provide an outline and discussion about the recently established and emerging recommendations regarding endovascular treatment of stroke.

RECENT FINDINGS

The indications for ET have expanded continually, with perfusion imaging now enabling selection of patients presenting 6-24 h after last-known-well, and improved device and operator proficiency allowing treatment of M2-MCA occlusions and tandem occlusions. Further inclusion of paediatric patients and patients with larger infarct core or milder stroke symptoms for ET has been proposed; however, this remains unproven. This growing applicability is supported by more efficient systems of care, employing modern techniques such as telemedicine, mobile stroke units and helicopter medical services. Ongoing debate exists regarding thrombolytic agent, thrombectomy technique, anaesthesia method and the role of advanced neuroimaging, with upcoming RCTs expected to provide clarification. The journey to further improving the efficacy of ET has advanced and diversified rapidly over recent years, involving improved patient selection, increased utility of advanced neuroimaging and ongoing device redevelopment, within the setting of more efficient, streamlined systems of care. This dynamic and ongoing influx of evidence-based refinements is key to further optimising outcomes for ELVO patients.

Effect of the Number of Neurointerventionalists on Off-Hour Endovascular Therapy for Acute Ischemic Stroke Within 12 Hours of Symptom Onset

Background

Off‐hour presentation can affect treatment delay and clinical outcomes in endovascular therapy (EVT) for acute ischemic stroke. We aimed to examine the treatment delays and clinical outcomes of EVT between on‐ and off‐hour admission and to evaluate the effect of hospital procedure volume and the number of neurointerventionalists on off‐hour EVT.

Methods and Results

From a multicenter registry, we identified patients who were treated with EVT within 12 hours of symptom. Annual hospital procedure volume was divided as low (<30), medium (30–60), and high (>60). The effect of the number of neurointerventionalists and annual hospital procedure volume on clinical outcome was estimated by the generalized estimation equation. Of the 31 133 stroke patients, 1564 patients met the eligibility criteria (mean age: 69±12 years; median baseline National Institutes of Health stroke scale score, 15 [interquartile range, 10–19]). Of 1564 patients, 893 (57.1%) arrived during off‐hour. The off‐hour patients had greater median door‐to‐puncture time (110  versus 95 minutes; P<0.001) compared with on‐hour patients. Despite the treatment delay, the functional outcome at 3 months did not differ between off‐ and on‐hour (odds ratio with 95% CI for 3‐month modified Rankin Scale 0–2, 0.99 [0.78–1.25]; P=0.90). The presence of three neurointerventionalists was significantly associated with favorable outcomes at 3 months during on‐ and off‐hour (2.07 [1.53–2.81]; P<0.001). The association was not observed for annual hospital procedural volume and the functional outcomes.

Conclusions

The number of neurointerventionalists was more crucial to effective around‐the‐clock EVT for acute stroke patients than hospital procedural volume.