Large Vessel Occlusion Score: A Screening Tool to Detect Large Vessel Occlusion in the Acute Stroke Setting

Baseline neurological deficit and argatroban plus alteplase in acute ischemic stroke: A post hoc analysis of ARAIS trial

BACKGROUND

The ARAIS trial didn't demonstrate argatroban significantly improve functional outcome at 90 days in acute ischemic stroke. We conducted post hoc analysis of ARAIS to investigate whether baseline neurological deficit was associated with outcomes.

METHODS

Patients without endovascular therapy who met screening criteria as protocol and completed argatroban treatment were enrolled and classified into two subgroups according to NIHSS score at admission. Primary outcome was excellent functional outcome at 90 days, defined as mRS score of 0 to 1. Early neurological deterioration (END), defined as an increase of ≥4 in the NIHSS score from baseline within 48 hours, was investigated as secondary outcome. Compared with alteplase alone, we investigated treatment effect of argatroban plus alteplase on outcomes in subgroups and interaction with subgroups.

RESULTS

A total of 675 patients from full analysis set were included: 390 were assigned into NIHSS score <10 subgroup and 285 into NIHSS score ≥10 subgroup. For primary outcome, there was similar treatment effect between argatroban plus alteplase and alteplase alone in NIHSS score ≥10 subgroup (adjusted RD, 5.8%; 95% CI, -6.0% to 17.5%; P = 0.33) and in NIHSS score <10 subgroup (adjusted RD, -1.4%; 95% CI, -9.9% to 7.1%; P = 0.75), and no significant interaction (P = 0.43). Occurrence of early neurological deterioration within 48 hours were significantly lower in NIHSS score ≥10 subgroup, compared with NIHSS score <10 subgroup (P = 0.006).

CONCLUSION

Among patients with NIHSS score ≥10, argatroban plus alteplase could safely reduce END within 48 hours.

Estimated number of eligible patients for mechanical thrombectomy based on NIHSS and population-based Brest stroke registry

BACKGROUND

Since 2015, mechanical thrombectomy (MT) is indicated as a treatment for patients with large vessel occlusion (LVO) at the acute phase of ischemic stroke. However, the number of stroke patients eligible for MT is poorly known.

OBJECTIVE

The objective of our study was to estimate the number of patients eligible for thrombectomy within the first 24hours of an ischemic stroke, based on the clinical National Institute of Health Stroke Scale (NIHSS).

METHOD

Our study concerned all ischemic strokes which occurred between January 2013 and December 2016 recorded in the population-based Brest Stroke Registry (BSR). Based on positive predictive value and negative predictive value from articles evaluating the performance of a defined NIHSS threshold to identify LVO, we first estimated the frequency of patients with LVO and then the frequency of patients eligible for MT depending on pre-stroke modified Rankin score (mRS). Our results were extrapolated to regions of metropolitan France. Two scenarios were considered: one called "stringent criteria" with mRS ≤1 and one called "real-life" criteria with mRS ≤2.

RESULT

We analyzed data from 2,025 ischemic strokes with symptom onset ≤24hours. No statistical difference between patient characteristics according to the time of hospital admission (≤6H vs. 6-24H) was observed. Based on NIHSS scores, between 23.90% and 44.20% of ischemic strokes admitted within the first six hours had LVO clinical characteristics. Among them, 14.53% to 26.87% met the ``stringent eligibility'' criteria for MT and 16.9 to 31.25% for ``real-life'' criteria. Eligible patients represented 6.32% to 11.70% of all ischemic strokes, irrespective of admission time. In France, 75 to 162 persons per million inhabitants per year were eligible for endovascular therapy, depending on including criteria. Based on activity levels recorded by the French Neuroradiology Society (SFNR) in 2018, the estimated needed increase in MT showed a heterogeneous pattern region-by-region, with the greatest need in Brittany, Pays de la Loire, and Corsica.

CONCLUSION

Based on NIHSS, our study provides coherent information concerning the estimated number of MT procedures to be performed in France: 4,877 to 10,494 ischemic strokes would be eligible each year in metropolitan France compared to the 6,596 thrombectomy procedures actually performed in 2018. Depending on the region, an estimated 10-20% to 90-100% increase in MT activity would be necessary to meet patient needs. These data suggest that there is still room for improvement in thrombectomy activity, particularly in certain regions of France, to allow equal access to MT to the entire French population.

Emerging Detection Techniques for Large Vessel Occlusion Stroke: A Scoping Review

Background: Large vessel occlusion (LVO) is the obstruction of large, proximal cerebral arteries and can account for up to 46% of acute ischaemic stroke (AIS) when both the A2 and P2 segments are included (from the anterior and posterior cerebral arteries). It is of paramount importance that LVO is promptly recognised to provide timely and effective acute stroke management. This review aims to scope recent literature to identify new emerging detection techniques for LVO. As a good comparator throughout this review, the commonly used National Institutes of Health Stroke Scale (NIHSS), at a cut-off of ≥11, has been reported to have a sensitivity of 86% and a specificity of 60% for LVO. Methods: Four electronic databases (Medline via OVID, CINAHL, Scopus, and Web of Science), and grey literature using OpenGrey, were systematically searched for published literature investigating developments in detection methods for LVO, reported from 2015 to 2021. The protocol for the search was published with the Open Science Framework (10.17605/OSF.IO/A98KN). Two independent researchers screened the titles, abstracts, and full texts of the articles, assessing their eligibility for inclusion. Results: The search identified 5,082 articles, in which 2,265 articles were screened to assess their eligibility. Sixty-two studies remained following full-text screening. LVO detection techniques were categorised into 5 groups: stroke scales (n = 30), imaging and physiological methods (n = 15), algorithmic and machine learning approaches (n = 9), physical symptoms (n = 5), and biomarkers (n = 3). Conclusions: This scoping review has explored literature on novel and advancements in pre-existing detection methods for LVO. The results of this review highlight LVO detection techniques, such as stroke scales and biomarkers, with good sensitivity and specificity performance, whilst also showing advancements to support existing LVO confirmatory methods, such as neuroimaging.

Imaging as a Selection Tool for Thrombectomy in Acute Ischemic Stroke: Pathophysiologic Considerations

Large vessel occlusion (LVO) stroke represents a stroke subset associated with the highest morbidity and mortality. Multiple prospective randomized trials have shown that thrombectomy, alone or in conjunction with IV thrombolysis, is highly effective in reestablishing cerebral perfusion and improving clinical outcomes. In unselected patients and especially in patients with poor collaterals, the benefit of reperfusion therapy is exquisitely time sensitive; the earlier thrombectomy is started, the lower the likelihood of disability or death. Understanding both the pathophysiologic underpinnings and the modifying factors of this strong time-to-treatment effect demonstrated in numerous randomized clinical trials is important for implementation of intrahospital workflow measures to maximize time efficiency of thrombectomy. Reducing delays in reperfusion therapy initiation has become a priority in acute stroke care, and therefore a thorough understanding of the main systems-based factors responsible for these delays is critical. Because the time spent evaluating the patient in the emergency department, which typically includes neuroimaging studies performed in scanners remote from the angiography suite, represents the main source of delays in thrombectomy initiation, the direct to angiography (DTA) model has emerged as a means to substantially reduce treatment times and is being instituted at an increasing number of thrombectomy centers across the world. The aim of this report is to introduce DTA as an emerging stroke care paradigm for patients with suspicion of LVO stroke, review results from studies evaluating its feasibility and impact on outcomes, describe current barriers to its more widespread adoption, and propose potential solutions to overcoming these barriers.

Prediction of large vessel occlusion for ischaemic stroke by using the machine learning model random forests

BACKGROUNDS

The timely identification of large vessel occlusion (LVO) in the prehospital stage is extremely important given the disease morbidity and narrow time window for intervention. The current evaluation strategies still remain challenging. The goal of this study was to develop a machine learning (ML) model to predict LVO using prehospital accessible data.

METHODS

Consecutive acute ischaemic stroke patients who underwent CT or MR angiography and received reperfusion therapy within 8 hours from symptom onset in the Computer-based Online Database of Acute Stroke Patients for Stroke Management Quality Evaluation-II dataset from January 2016 to August 2021 were included. We developed eight ML models to integrate National Institutes of Health Stroke Scale (NIHSS) items with demographics, medical history and vascular risk factors to identify LVO and validate its efficiency.

RESULTS

Finally, 15 365 patients were included in the training set and 4215 patients were included in the test set. On the test set, random forests (RF), gradient boosting machine and extreme gradient boosting presented area under the curve (AUC) of 0.831 (95% CI 0.819 to 0.843), which were higher than other models, and RF presented the highest specificity (0.827). In addition, the AUC of RF was higher than other scales, and the accuracy of the model was improved by 6.4% compared with NIHSS. We also found the top five items of identifying LVO were total NIHSS score, gaze deviation, level of consciousness (LOC), LOC commands and motor left leg.

CONCLUSIONS

Our proposed model could be a useful screening tool to predict LVO based on the prehospital accessible medical data.

TRIAL REGISTRATION NUMBER

NCT04487340.

The Hyperdense Middle Cerebral Artery Sign in Drip-and-Ship Models of Acute Stroke Management

Background

Large vessel occlusion (LVO) leads to debilitating stroke and responds modestly to recombinant tissue plasminogen activator (rt-TPA). Early thrombectomy improves functional outcomes in selected patients with proximal occlusion but it is not available in all medical facilities. The best imaging modality for triage in an acute stroke setting in drip-and-ship models is still the subject of debate.

Objectives

We aimed to assess the diagnostic value of millimeter-sliced noncontrast computed tomography (NCCT) hyperdense middle cerebral artery sign (HMCAS) in itself or associated with clinical data for early detection of LVO in drip-and-ship models of acute stroke management.

Methods

NCCT of patients admitted to the Erasme Hospital, ULB, Brussels, Belgium, for suspicion of acute ischemic stroke between January 1 and July 31, 2017, were collected. Patients with brain hemorrhages were excluded, leading to 122 cases. The presence of HMCAS on NCCT was determined via visual assessment by 6 raters blinded to all other data. An independent rater assessed the presence of LVO on digital subtraction angiography imaging or contrast-enhanced CT angiography (CTA). The sensitivity, false-positive rate (FPR), and accuracy of HMCAS and the dot sign to detect LVO were calculated. The interobserver agreement of HMCAS was assessed using Gwet's AC1 coefficient. Then, on a separate occasion, the first 2 observers rereviewed all NCCT provided with clinical clues. The sensitivity, FPR, and accuracy of HMCAS were recalculated.

Results

HMCAS was found in 21% of the cases and a dot sign was found in 9%. The mean HMCAS sensitivity was 62% (95% CI 45–79%) and its accuracy was 86% (95% CI 79–92%) for detecting LVO. The interobserver reliability coefficient was 80% for HMCAS. Combined with clinical information, HMCAS sensitivity increased to 81% (95% CI 68–94; p = 0.041) and accuracy increased to 91% (95% CI 86–96%).

Conclusion

When clinical data are provided, detection of HMCAS on thinly sliced NCCT could be enough to decide on transfer for thrombectomy in drip-and-ship models of acute stroke management, especially in situations where CTA is less available and referral centers for thrombectomy fewer and further apart.