Alberta Stroke Program Early CT Score Research Articles

Impact of relative cerebral blood volume reduction on early neurological improvement in extensive ischemic stroke.

The benefit of endovascular treatment (EVT) for patients with low Alberta Stroke Program early computed tomography score (ASPECTS) is still ambiguous and is currently being investigated in randomized trials. Computed tomography (CT) perfusion, used to estimate infarct extent and progression, might predict early neurological improvement (ENI) after EVT. We hypothesized that the degree of relative cerebral blood volume (rCBV) reduction is directly associated with ENI in low ASPECTS patients undergoing EVT. Ischemic stroke patients with ASPECTS ≤ 5 who received multimodal CT and underwent thrombectomy were analyzed. rCBV reduction was defined as the ratio of cerebral blood volume (CBV), measured in the ischemic lesion to contralateral CBV. Complete reperfusion was defined as an expanded Thrombolysis in Cerebral Infarction score 2c-3. The clinical endpoint was ENI at 24 h, defined continuously (National Institutes of Health Stroke Scale [NIHSS] score change from baseline to 24 h) and binarized (NIHSS score at 24 h ≤ 8). A total of 102 patients were included. Lower rCBV reduction and complete EVT were independently associated with ENI (-11.4 NIHSS points, p= 0.04; -7.3 points, p< 0.0001, respectively). The effect of complete EVT on ENI was directly linked to the degree of rCBV reduction: the probability for binary ENI was +34.6% (p= 0.004) in patients with low rCBV reduction versus +8.2% (p= 0.28) in patients with high rCBV reduction). In patients with ischemic stroke with low ASPECTS, ENI was directly linked to the degree of rCBV reduction, a potential indicator of ischemia depth in extensive baseline infarction. Lower rCBV reduction was associated with higher probability of ENI after complete reperfusion, suggesting less pronounced lesion progression despite its large extent and hence, a higher susceptibility to EVT.

Nomograms predict prognosis and hospitalization time using non-contrast CT and CT perfusion in patients with ischemic stroke.

BackgroundStroke is a major disease with high morbidity and mortality worldwide. Currently, there is no quantitative method to evaluate the short-term prognosis and length of hospitalization of patients.PurposeWe aimed to develop nomograms as prognosis predictors based on imaging characteristics from non-contrast computed tomography (NCCT) and CT perfusion (CTP) and clinical characteristics for predicting activity of daily living (ADL) and hospitalization time of patients with ischemic stroke.Materials and methodsA total of 476 patients were enrolled in the study and divided into the training set (n = 381) and testing set (n = 95). Each of them owned NCCT and CTP images. We propose to extract imaging features representing as the Alberta stroke program early CT score (ASPECTS) values from NCCT, ischemic lesion volumes from CBF, and TMAX maps from CTP. Based on imaging features and clinical characteristics, we addressed two main issues: (1) predicting prognosis according to the Barthel index (BI)–binary logistic regression analysis was employed for feature selection, and the resulting nomogram was assessed in terms of discrimination capability, calibration, and clinical utility and (2) predicting the hospitalization time of patients–the Cox proportional hazard model was used for this purpose. After feature selection, another specific nomogram was established with calibration curves and time-dependent ROC curves for evaluation.ResultsIn the task of predicting binary prognosis outcome, a nomogram was constructed with the area under the curve (AUC) value of 0.883 (95% CI: 0.781–0.985), the accuracy of 0.853, and F1-scores of 0.909 in the testing set. We further tried to predict discharge BI into four classes. Similar performance was achieved as an AUC of 0.890 in the testing set. In the task of predicting hospitalization time, the Cox proportional hazard model was used. The concordance index of the model was 0.700 (SE = 0.019), and AUCs for predicting discharge at a specific week were higher than 0.80, which demonstrated the superior performance of the model.ConclusionThe novel non-invasive NCCT- and CTP-based nomograms could predict short-term ADL and hospitalization time of patients with ischemic stroke, thus allowing a personalized clinical outcome prediction and showing great potential in improving clinical efficiency.SummaryCombining NCCT- and CTP-based nomograms could accurately predict short-term outcomes of patients with ischemic stroke, including whose discharge BI and the length of hospital stay.Key ResultsUsing a large dataset of 1,310 patients, we show a novel nomogram with a good performance in predicting discharge BI class of patients (AUCs > 0.850). The second nomogram owns an excellent ability to predict the length of hospital stay (AUCs > 0.800).

Pre-admission antithrombotic use is associated with 3-month mRS score after thrombectomy for acute ischemic stroke.

In patients who undergo thrombectomy for acute ischemic stroke, the relationship between pre-admission antithrombotic (anticoagulation or antiplatelet) use and both radiographic and functional outcome is not well understood. We sought to explore the relationship between pre-admission antithrombotic use in patients who underwent thrombectomy for acute ischemic stroke at two medical centers in New York City between December 2018 and November 2020. Analyses were performed using analysis of variance and Pearson’s chi-squared tests. Of 234 patients in the analysis cohort, 65 (28%) were on anticoagulation, 64 (27%) were on antiplatelet, and 105 (45%) with no antithrombotic use pre-admission. 3-month Modified Rankin Scale (mRS) score of 3–6 was associated with pre-admission antithrombotic use (71% anticoagulation vs. 77% antiplatelet vs. 56% no antithrombotic, p = 0.04). There was no relationship between pre-admission antithrombotic use and Thrombolysis in Cerebral Iinfarction (TICI) score, post-procedure Alberta Stroke Program Early CT Score (ASPECTS) score, rate of hemorrhagic conversion, length of hospital admission, discharge NIH Stroke Scale (NIHSS), discharge mRS score, or mortality. When initial NIHSS score, post-procedure ASPECTS score, and age at admission were included in multivariate analysis, pre-admission antithrombotic use was still significantly associated with a 3-month mRS score of 3–6 (OR 2.36, 95% CI 1.03–5.54, p = 0.04). In this cohort of patients with acute ischemic stroke who underwent thrombectomy, pre-admission antithrombotic use was associated with 3-month mRS score, but no other measures of radiographic or functional outcome. Further research is needed on the relationship between use of specific anticoagulation or antiplatelet agents and outcome after acute ischemic stroke, but moreover, improve stroke prevention.

Postinterventional contrast accumulation early predicts malignant stroke in successfully recanalized patients with emergent large vessel occlusion

Background and objectiveA notable proportion of patients with emergent large vessel occlusion experience malignant middle cerebral infarct (MMI) despite successful recanalization with thrombectomy. In this study, we aim to identify early predictors of MMI in patients successfully recanalized by thrombectomy. MethodsWe retrospectively analyzed atotal of 144 anterior circulation emergent large vessel occlusion patients (90 males and 54 females; mean yr ± SD, 67.7 ± 13.2) who were successfully recanalized by thrombectomy (thrombolysis in cerebral infarction perfusion scale 2b or 3) in the cerebrovascular center of the Soonchunhyang University Bucheon Hospital in South Korea between January 2012 and September 2021. Using pretreatment CT angiography source images (CTA-SIs), collateral status was evaluated, and the Alberta stroke program early CT score (ASPECTS) was determined. Contrast accumulation (CA) was evaluated on non-contrast brain CT scans performed immediately after thrombectomy procedures. Logistic regression and receiver operating characteristic curve analyses were performed using SPSS software, version 26. ResultsNineteen patients (13.2 %, 10 males and 9 females; mean yr ± SD, 67.9 ± 11.3) experienced MMI. The collateral status was poorer (p < 0.001) and the CTA-SI ASPECTS was lower (p < 0.001) in the MMI group than in the non-MMI group. Furthermore, postinterventional CA was more frequent in the MMI group (94.7 % vs 65.6 %, p = 0.010). In particular, distribution of CA was different between the MMI and non-MMI groups. Cortical and subarachnoid CA was more frequent in the MMI group than in the non-MMI group (94.7 % vs 49.6 %, p < 0.001 and 89.5 % vs 20.8 %, p < 0.001). In addition, the ASPECTS for CA, wherein each region was scored 0 if CA existed, were lower in the MMI group (p < 0.001). Multivariate analysis showed that cortical CA, subarachnoid CA, and CA ASPECTS were associated with MMI. A CA ASPECTS ≤ 6 predicted MMI with a sensitivity of 94.7 % and a specificity of 77.6 % (area under the curve, 0.87). ConclusionsOur study shows that the MMI risk in successfully recanalized patients can be predicted by using a simple CT scan immediately after thrombectomy. A cortical or subarachnoid location of CA and lower CA ASPECTS can early predict the future occurrence of MMI.

Association between anemic status on admission and clinical outcomes of acute large vessel occlusion

BackgroundAnemia is a frequently observed condition, but its clinical impact on large vessel occlusion (LVO) remains unclear. We examined the association between anemic status on admission and clinical outcomes of LVO in a real-world setting. MethodsWe conducted a post-hoc analysis of the RESCUE-Japan Registry 2, a nationwide registry which enrolled 2408 consecutive patients with LVO who were admitted within 24 h of onset. The patients were classified into anemia (<11 g/dL) and no-anemia (≥11 g/dL) groups according to their hemoglobin level on admission. The primary outcome was defined as a modified Rankin Scale of 0–2 at day 90. ResultsAmong the 2373 patients with available baseline hemoglobin data, 307 (13.0%) were classified in the anemia group. Anemia was associated with a lower likelihood of the primary outcome (adjusted odds ratio [OR]: 0.68; 95% confidence interval [CI]: 0.47–0.98) and higher mortality within 90 days (adjusted OR: 1.48; 95% CI: 1.01–2.17). Subgroup analyses showed that the likelihood of achieving the primary outcome between the two groups was different between men and women (P for interaction = 0.049), those with Alberta Stroke Program Early CT Score (ASPECTS) <6 and ASPECTS ≥6 (P for interaction = 0.02), and those with National Institute of Health Stroke Scale (NIHSS) ≥16 and NIHSS < 16 (P for interaction = 0.005). ConclusionsAnemic state on admission was associated with poorer clinical outcomes of LVO in real-world clinical practice. The effects of anemic status were larger in LVO patients with lower NIHSS or higher ASPECTS.

Alberta Stroke Program Early CT Score and collateral status predict target mismatch in large vessel occlusion with delayed time windows

BackgroundThe Alberta Stroke Program Early CT Score (ASPECTS) and collateral score (CS) are two readily available imaging metrics for the evaluation of acute ischemic stroke (AIS) with large vessel occlusion...

Assessment of Irreversible Tissue Injury in Extensive Ischemic Stroke-Potential of Quantitative Cerebral Perfusion.

Computed tomography perfusion (CTP) is used as a tool to select ischemic stroke patients for endovascular treatment (EVT) and is currently investigated in the setting of extensive stroke with low Alberta Stroke Program Early CT scores (ASPECTS). The purpose of this study was to perform a comprehensive quantitative analysis of cerebral blood flow within the ischemic lesion compared to threshold-derived core lesion volumes. We hypothesized that the degree of cerebral blood volume (CBV) reduction within the ischemic lesion is predictive of irreversible tissue injury and functional outcome in patients with low ASPECTS. Ischemic stroke patients with an ASPECTS ≤ 5 who received multimodal CT on admission and underwent thrombectomy were analyzed. The ischemic lesion on CTP was identified, and CTP-derived parameters were measured as absolute means within the lesion and relative to the physiological perfusion measured in a contralateral region of interest. The degree of irreversible tissue injury was assessed using quantitative net water uptake (NWU). Functional endpoint was good outcome defined as modified Rankin Scale (mRS) scores 0-3 at day 90. One hundred eleven patients were included. The median core lesion volume was 71ml (IQR: 25-107), and the median quantitative NWU was 9.5% (IQR: 6-13). Relative CBV (rCBV) reduction and ASPECTS at baseline were independently associated with NWU in multivariable linear regression analysis (ß: 12.4, 95%CI: 6.0-18.9, p < 0.0001) and (ß: - 0.78, 95% CI: - 1.53 to - 0.02; p = 0.045), respectively. Furthermore, rCBV was significantly associated with good outcome in patients with core volumes > 50ml (OR: 0.16, 95% CI: 0.05-0.49, p = 0.001). Our study shows that rCBV reduction serves as an early surrogate for increase of NWU as a marker of irreversible tissue injury and lesion progression. Thus, the analysis of rCBV reduction within ischemic lesions may add another dimension to acute stroke triage in addition to core volumes or ASPECTS as indicators of the infarct extent and viability.

Safety and Efficacy of Intravenous Alteplase before Endovascular Thrombectomy: A Pooled Analysis with Focus on the Elderly.

Current guidelines advocate intravenous thrombolysis (IVT) prior to endovascular thrombectomy (EVT) for all patients with acute ischemic stroke (AIS) due to large vessel occlusion (LVO). We evaluated outcomes with and without IVT pretreatment. Our institutional protocols allow AIS patients presenting early (<4 h from onset or last seen normal) who have an Alberta Stroke Program Early CT Score (ASPECTS) ≥6 to undergo EVT without IVT pretreatment if the endovascular team is in the hospital (direct EVT). Rates of recanalization and hemorrhagic transformation (HT) and neurological outcomes were retrospectively compared in consecutive patients undergoing IVT+EVT vs. direct EVT with subanalyses in those ≥80 years and ≥85 years. In the overall cohort (IVT+EVT = 147, direct EVT = 162), and in subsets of patients ≥80 years (IVT+EVT = 51, direct EVT = 50) and ≥85 years (IVT+EVT = 19, direct EVT = 32), the IVT+EVT cohort and the direct EVT group had similar baseline characteristics, underwent EVT after a comparable interval from symptom onset, and reached similar rates of target vessel recanalization. No differences were observed in the HT frequency, or in disability at discharge or after 90 days. Patients receiving direct EVT underwent more stenting of the carotid artery due to stenosis during the EVT procedure (22% vs. 6%, p = 0.001). Direct EVT and IVT+EVT had comparable neurological outcomes in the overall cohort and in the subgroups of patients ≥80 and ≥85 years, suggesting that direct EVT should be considered in patients with an elevated risk for HT.

Mechanical thrombectomy failure in anterior circulation strokes: Outcomes and predictors of favorable outcome.

Background and purposeDespite continuous improvement and growing knowledge in the endovascular therapy of large vessel occlusion stroke (LVOS), mechanical thrombectomy (MT) still fails to obtain satisfying intracranial recanalization in 10% to 15% of cases. However, little is known regarding clinical and radiological outcomes among this singularly underexplored subpopulation undergoing failed MT. We aimed to investigate the outcome after failed MT and identify predictive factors of favorable outcome despite recanalization failure.MethodsWe conducted a retrospective analysis of consecutive patients prospectively included in the ongoing observational multicenter Endovascular Treatment in Ischemic Stroke registry from January 2015 to September 2020. Patients presenting with anterior circulation LVOS treated with MT but experiencing failed intracranial recanalization defined as final modified Thrombolysis In Cerebral Infarction (mTICI) score of 0, 1 and 2a were included. Clinical and radiological outcomes were assessed along with the exploration of predictive factors of Day‐90 favorable outcome.ResultsThe study population comprised 533 patients. Mean age was 68.8 ± 16 years, and median admission National Institutes of Health Stroke Scale (NIHSS) and Alberta Stroke Program Early Computed Tomography Score (ASPECTS) were 17 (IQR 12–21) and 7 (IQR 5–8), respectively. Favorable outcomes were observed in 85 patients (18.2%) and 186 died (39.0%). The rate of symptomatic intracranial hemorrhage was 14.1%. In multivariable analysis, younger age (odds ratio [OR] 0.96, 95% CI 0.94–0.98, p < 0.001), a lower admission NIHSS (OR 0.87, 95% CI 0.83–0.91, p < 0.001), a lower number of MT passes (OR 0.77, 95% CI 0.77–0.87, p < 0.001), a lower delta ASPECTS between initial and Day‐1 imaging (OR 0.83, 95% CI 0.71–0.98, p = 0.026) and stroke etiology [significant difference among etiological subtypes (p = 0.024) with a tendency toward more favorable outcomes for dissection (OR 2.01, 95% CI 0.71–5.67)] were significantly associated with a 90‐day favorable outcome.ConclusionsIn this large retrospective analysis of a multicenter registry, we quantified the poor outcome after MT failure. We also identified factors associated with favorable outcome despite recanalization failure that might influence therapeutic management.

Prognostic value of ASPECTS on post-treatment diffusion-weighted imaging for acute ischemic stroke patients after endovascular thrombectomy: comparison with infarction volume.

To assess the prognostic value of Alberta Stroke Program Early Computed Tomography Score (ASPECTS) on post-treatment diffusion-weighted imaging (DWI) for acute ischemic stroke (AIS) patients after endovascular thrombectomy (EVT) and compare it with that of infarction volume. Ninety-eight consecutive AIS patients who underwent EVT and post-treatment DWI were retrospectively enrolled. ASPECTS and infarction volume were evaluated based on post-treatment DWI, respectively. Good clinical outcome was defined as modified Rankin Scale score of 0-2 at 90 days. Predictors of good clinical outcome were evaluated using univariate and multivariate logistic regression analysis. Prognostic value of post-treatment DWI ASPECTS and infarction volume were assessed and compared using receiver-operating-characteristic curves and the DeLong method. Favorable outcome was achieved in 62 (63.3%) patients. A strong correlation was found between post-treatment DWI ASPECTS and infarction volume (ρ = -0.847). Due to strong correlation and potential collinearity, two multivariate logistic regression models were respectively developed which included post-treatment DWI ASPECTS or infarction volume. As a result, post-treatment DWI ASPECTS (OR, 2.401; 95%CI, 1.567-3.678; p < 0.001) and infarction volume (OR, 0.982; 95%CI, 0.846-0.998; p = 0.002) were both independent predictors of good clinical outcome. Setting post-treatment DWI ASPECTS ≥ 6 as a cut-off value, optimal performance (AUC = 0.836; sensitivity, 87.1%; specificity, 66.7%) could be obtained in predicting good clinical outcome, which was comparable with that of infarction volume (cut-off volume, ≤ 94.87 ml; AUC = 0.821; sensitivity, 90.3%; specificity, 55.6%). Post-treatment DWI ASPECTS might be a potential surrogate of infarction volume and be effective in predicting the clinical outcome of AIS patients after EVT. • Post-treatment DWI ASPECTS correlated significantly with infarction volume. • A post-treatment DWI ASPECTS ≥ 6 best predicts good outcomes for AIS patients after EVT. • Post-treatment DWI ASPECTS has the potential in substituting infarction volume in predicting the clinical outcome of AIS patients.

Clinical validation of an AI-based motion correction reconstruction algorithm in cerebral CT.

To evaluate the clinical performance of an artificial intelligence (AI)-based motion correction (MC) reconstruction algorithm for cerebral CT. A total of 53 cases, where motion artifacts were found in the first scan so that an immediate rescan was taken, were retrospectively enrolled. While the rescanned images were reconstructed with a hybrid iterative reconstruction (IR) algorithm (reference group), images of the first scan were reconstructed with both the hybrid IR (motion group) and the MC algorithm (MC group). Image quality was compared in terms of standard deviation (SD), signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR), the mean squared error (MSE), peak signal-to-noise ratio (PSNR), structural similarity index (SSIM), and mutual information (MI), as well as subjective scores. The diagnostic performance for each case was evaluated accordingly by lesion detectability or the Alberta Stroke Program Early CT Score (ASPECTS) assessment. Compared with the motion group, the SNR and CNR of the MC group were significantly increased. The MSE, PSNR, SSIM, and MI with respect to the reference group were improved by 44.1%, 15.8%, 7.4%, and 18.3%, respectively (all p < 0.001). Subjective image quality indicators were scored higher for the MC than the motion group (p < 0.05). Improved lesion detectability and higher AUC (0.817 vs 0.614) in the ASPECTS assessment were found for the MC to the motion group. The AI-based MC reconstruction algorithm has been clinically validated for reducing motion artifacts and improving diagnostic performance of cerebral CT. • An artificial intelligence-based motion correction (MC) reconstruction algorithm has been clinically validated in both qualitative and quantitative manner. • The MC algorithm reduces motion artifacts in cerebral CT and increases the diagnostic confidence for brain lesions. • The MC algorithm can help avoiding rescans caused by motion and improving the efficiency of cerebral CT in the emergency department.

ASPECTS as a clinical outcome marker for MCA infarction treated with thrombolytic therapy: Non-contrast CT versus CTA source images

Background &amp; Objective: Computed tomography angiography (CTA) in acute stroke has been widely used to demonstrate arterial occlusion. Alberta Stroke Program Early CT Score (ASPECTS) is used to detect early ischemic signs in non-contrast computed tomography (NCCT) in the middle cerebral artery region. We hypothesized that computed tomography angiography source image (CTA-SI) is superior to NCCT in predicting final infarct volume, 24 hour National Institutes of Health Stroke Scale (NIHSS) score and 90-day clinical outcome. Methods: Patients who had an acute ischemic stroke due to middle cerebral artery (MCA) occlusion and treated with tissue plasminogen activator (tPA) were retrospectively evaluated. ASPECTS was evaluated by two experienced stroke neurologists in acute NCCT, CTA-SI, and follow up imaging. The final ASPECTS was compared with the mean baseline ASPECTS of NCCT and CTA-SI. The relation of both scores with 24-hour NIHSS and clinical outcome was compared. The Modified Rankin Scale (mRS) was utilized to evaluate the 90-day outcomes. mRS score of 0-2 was considered a “good outcome”. Results: Fifty-three patients were evaluated. We observed a significant relation among CTA-SI ASPECTS and after treatment 24hr ASPECTS (y= -3.9 + 1.4 x; 95% CI, -7.6 to -0.2) (y= -26.04 + 3.5 x; CI, -41 to -10). The median baseline 24-hr NHISS was 6 (0 - 22). We found a better correlation between CTA-SI ASPECTS and 24-hr NHISS (y= 363.06 + -37.03 x; CI, -148 to 864) than between NCCT ASPECTS and 24h NHISS (y=529.80 + -62.55 x; CI, 180 - 829). Median 90 days mRS score was 2 (0 - 6). According to Deming regression analysis, the CTA-SI ASPECTS (y= 76.10 + -7.69 x; 95% CI, -36 to 188) was more consistent with the 90 day mRS compared to NCCT ASPECTS (y=149.86 + -17.67 x; 95% CI, 23 - 267) CTA-SI was superior in predicting 24hr NIHSS and day 90 mRS compared to NCCT ASPECTS. Conclusion: Prediction of CTA-SI ASPECTs is better than NCCT ASPECTs at 24hr NIHSS, 3-month mRS and final infarct size in acute ischemic stroke patients treated with tPA.

Ultra‐Early Functional Improvement After Stroke Thrombectomy – Predictors and Implications

Background Neurocritical care is routinely provided to patients post‐endovascular thrombectomy (EVT) for anterior large vessel occlusion strokes. We aim to study the relationship between immediate improvement in National Institutes of Health Stroke Scale (NIHSS) score on outcomes post‐EVT and potential implications for postprocedural care. Methods We performed a retrospective review of anterior circulation large vessel occlusion (internal carotid/proximal middle cerebral artery) patients undergoing EVT. Demographic, clinical, and imaging information was analyzed. Ultra‐early functional improvement (UEFI) was defined as NIHSS score &lt;6 within 30 minutes of successful recanalization. We analyzed the incidence and predictors of UEFI, and explored reasons for neurological decline post‐UEFI. Results Of the 343 anterior large vessel occlusion patients undergoing EVT, mean age was 71 ± 15 and 46% were male. Mean NIHSS was 17 ± 6 and Time Last Known Well (TLKW) to arrival was 9 ± 11 hours. UEFI was observed in 23% (79/343) of patients. Independent predictors of UEFI included lower pretreatment NIHSS, favorable Alberta Stroke Program Early CT Score (ASPECTS), and lower admission systolic blood pressure. Rates of 90‐day‐modified Rankin scale 0–2 were higher (71% versus 33%, P &lt;0.01) and the rate of mortality (8% versus 28%, P &lt;0.01) was lower in the UEFI group compared with the non‐UEFI group. Amongst patients with UEFI, 1.3% (1/79) experienced increase in NIHSS by ≥4 points within 24 hours of EVT. This patient received thrombolysis, achieved TICI‐2B recanalization, and follow‐up neuroimaging revealed a parenchymal hemorrhage and an infarct volume of 44 mL. None of the patients with UEFI required continuous antihypertensive infusions. Conclusions Approximately 1‐in‐4 of anterior large vessel occlusion stroke patients undergoing EVT have an NIHSS score of &lt;6 within 30 minutes of successful recanalization. Only 1% of them experience significant decline in neurological status within 24 hours of the procedure with the majority achieving functional independence at 90 days. The need for advanced neurocritical care should be reevaluated in these patients.

ASPECTS: interobserver agreement between radiologist

Introduction. The Alberta stroke programme early CT score (ASPECTS) was developed for a unified approach to the diagnosis of Acute Ischemic Stroke. ASPECTS is currently used as a standard method for assessment of ischemic volumes in the anterior cerebral circulation. However, the scale is not fully standardized, which is a source of intersubject variability.The purpose of the review is to gain an understanding the advantages and limitations of the ASPECTS scale, as well as the level of inter-expert and intra-expert agreement.Results. A literary analysis demonstrates most researchers have identified many factors that affect both the interpretation and assessment of the distribution of ischemic changes by ASPECTS. These signs are diverse and include a wide range of parameters: from methodological standardization to personal factors of experts. Also, studies on the effectiveness of the ASPECTS scale showed quite heterogeneous results, which reflect a wide degree of variability in inter-expert agreement.Conclusion. The ASPECTS is a systematic, reliable and practical method that is widely used in modern clinical practice. However, the possibility of variability of expert assessments is the main limitation of its application. The pronounced variety of results and the heterogeneity of intrasubject variability does not currently allow us to consider this scale as a truly reliable version of a standardized assessment and may affect the further treatment process. To solve this problem, it looks promising to introduce into clinical practice the methods of semi-automatic and automatic processing of CT images using artificial intelligence systems. But for the full acceptance of such systems into clinical practice, their wide clinical approbation on independent sets of different data is necessary.

Hypoperfusion intensity ratio correlates with clinical outcome of endovascular thrombectomy in acute ischaemic stroke patients with late therapeutic window

To evaluate the prognostic value of the hypoperfusion intensity ratio (HIR) on 90-day clinical outcome in acute ischaemic stroke (AIS) patients with late therapeutic window. One hundred and sixty-eight consecutive AIS patients with anterior-circulation large-vessel occlusion who underwent endovascular thrombectomy during the late window were enrolled retrospectively. Clinical data, Alberta Stroke Program Early Computed Tomography Score (ASPECTS) based on unenhanced computed tomography (CT), and perfusion parameters included ischaemic core, hypoperfusion volume, mismatch volume between core and penumbra, and the HIR were assessed and compared between patients with or without favourable outcomes (defined as modified Rankin Scale score of 0-2). Statistical analysis included binary logistic regression and receiver operating characteristic (ROC) analyses. A favourable outcome was achieved in 76 (45.2%) patients. In univariable analysis, age, National Institutes of Health Stroke Scale (NIHSS) score at admission, ASPECTS score, HIR, ischaemic core, and hypoperfusion volume were significantly associated with functional outcome (p<0.05). In multivariate analyses, age (OR 0.95; 95% CI 0.92-0.99), NIHSS score at admission (OR 0.89, 95% CI 0.84-0.96) and HIR (OR 0.018, 95% CI 0.003-0.113) remained as independent outcome predictors (p<0.01). The optimal threshold of HIR was 0.36 (sensitivity 70.7%, specificity 61.8%). The combination of age, NIHSS score at admission, and HIR yield good performance for outcome prediction with an area under the ROC curve of 0.815 (sensitivity 88.2%, specificity 64.1%), significantly higher than individual variable (p<0.05). Low HIR was a predictor for favourable outcome in AIS patients with late therapeutic window. Integrating HIR with clinical variables improved the ability for outcome classification.

Prognostic Accuracy of CTP Summary Maps in Patients with Large Vessel Occlusive Stroke and Poor Revascularization after Mechanical Thrombectomy-Comparison of Three Automated Perfusion Software Applications.

Background: Innovative automated perfusion software solutions offer support in the management of acute stroke by providing information about the infarct core and penumbra. While the performance of different software solutions has mainly been investigated in patients with successful recanalization, the prognostic accuracy of the hypoperfusion maps in cases of futile recanalization has hardly been validated. Methods: In 39 patients with acute ischemic stroke (AIS) due to large vessel occlusion (LVO) in the anterior circulation and poor revascularization (thrombolysis in cerebral infarction (TICI) 0-2a) after mechanical thrombectomy (MT), hypoperfusion analysis was performed using three different automated perfusion software solutions (A: RAPID, B: Brainomix e-CTP, C: Syngo.via). The hypoperfusion volumes (HV) as Tmax > 6 s were compared with the final infarct volumes (FIV) on follow-up CT 36–48 h after futile recanalization. Bland–Altman analysis was applied to display the levels of agreement and to evaluate systematic differences. Based on the median hypoperfusion intensity ratio (HIR, volumetric ratio of tissue with a Tmax > 10 s and Tmax > 6 s) patients were dichotomized into high- and low-HIR groups. Subgroup analysis with favorable (<0.6) and unfavorable (≥0.6) HIR was performed with respect to the FIV. HIR was correlated to clinical baseline and outcome parameters using Pearson’s correlation. Results: Overall, there was good correlation without significant differences between the HVs and the FIVs with package A (r = 0.78, p < 0.001) being slightly superior to B and C. However, levels of agreement were very wide for all software applications in Bland-Altman analysis. In cases of large infarcts exceeding 150 mL the performance of the automated software solutions generally decreased. Subgroup analysis revealed the FIV to be generally underestimated in patients with HIR ≥ 0.6 (p < 0.05). In the subgroup with favorable HIR, however, there was a trend towards an overestimation of the FIV. Nevertheless, packages A and B showed good correlation between the HVs and FIVs without significant differences (p > 0.2), while only package C significantly overestimated the FIV (−54.6 ± 56.0 mL, p = 0.001). The rate of modified Rankin Scale (mRS) 0–3 after 3 months was significantly higher in favorable vs. unfavorable HIR (42.1% vs. 13.3%, p = 0.02). Lower HIR was associated with higher Alberta Stroke Program Early CT Score (ASPECTS) at presentation and on follow-up imaging, lower risk of malignant edema, and better outcome (p < 0.05). Conclusion: Overall, the performance of the automated perfusion software solutions to predict the FIV after futile recanalization is good, with decreasing accuracy in large infarcts exceeding 150 mL. However, depending on the HIR, FIV can be significantly over- and underestimated, with Syngo showing the widest range. Our results indicate that the HIR can serve as valuable parameter for outcome predictions and facilitate the decision whether or not to perform MT in delicate cases.

Science, Medicine, and the Anesthesiologist

Science, Medicine, and the Anesthesiologist

Bypassing the intensive care unit for patients with acute ischemic stroke secondary to large-vessel occlusion.

Endovascular mechanical thrombectomy is safe and effective for the treatment of acute ischemic stroke (AIS) due to large-vessel occlusion (LVO). Still, despite high rates of procedural success, it is routine practice to uniformly admit postthrombectomy patients to an intensive care unit (ICU) for postoperative observation. Predictors of ICU criteria and care requirements in the postmechanical thrombectomy ischemic stroke patient population are lacking. The goal of the present study is to identify risk factors associated with requiring ICU-level intervention following mechanical thrombectomy. The authors retrospectively analyzed data from 245 patients undergoing thrombectomy for AIS from anterior circulation LVO at a comprehensive stroke and tertiary care center from January 2015 to March 2020. Clinical variables that predicted the need for critical care intervention were identified and compared. The performance of a binary classification test constructed from these predictive variables was also evaluated using a validation cohort. Seventy-six patients (31%) required critical care interventions. A recanalization grade lower than modified Thrombolysis in Cerebral Infarction (mTICI) scale grade 2B (odds ratio [OR] 3.625, p = 0.001), Alberta Stroke Program Early Computed Tomography Score (ASPECTS) < 8 (OR 3.643, p < 0.001), and presence of hyperdensity on postprocedure cone-beam CT (OR 2.485, p = 0.005) were significantly associated with the need for postthrombectomy critical care intervention. When applied to a validation cohort, a clearance classification scheme using these three variables demonstrated high positive predictive value (0.88). A recanalization grade lower than mTICI 2B, ASPECTS < 8, and postprocedure hyperdensity on cone-beam CT were shown to be independent predictors of requiring ICU-level care. Routine admission to ICU-level care can be costly and confer increased risk for hospital-acquired conditions. Safely and reliably identifying low-risk patients has the potential for cost savings, value-based care, and decreasing hospital-acquired conditions.

A Dynamic Nomogram to Predict the 3-Month Unfavorable Outcome of Patients with Acute Ischemic Stroke.

PurposeDespite receiving standard-of-care treatments, a significant proportion of patients with acute ischemic stroke (AIS) are left with long-term functional impairment. Therefore, an easy-to-use tool for predicting of unfavorable outcome following AIS plays an important role in clinical practice. This study was aimed to develop a dynamic nomogram to predict the 3-month unfavorable outcome for AIS patients.MethodsThis was a prospective observational study conducted in consecutive patients with AIS admitted to our stroke center between September 2019 and June 2020. Baseline demographic, clinical, and laboratory information were obtained. The primary outcome was evaluated with modified Rankin Scale (mRS) scores at 3 months. Least absolute shrinkage and selection operator regression was used to select the optimal predictive factors. Multiple logistics regression was performed to establish the nomogram. Decision curve analysis (DCA) was applied to assess the clinical utility of the nomogram. The calibration and discrimination property of the nomogram was validated by calibration plots and concordance index.ResultsA total of 93 eligible patients were enrolled: 28 (30.1%) patients had unfavorable outcome (mRS >2). Glycosylated hemoglobin (OR, 1.541; 95% CI, 1.051–2.261), the Alberta Stroke Program Early Computed Tomography Score (ASPECTS) (OR, 0.635; 95% CI, 0.463–0.871), and National Institute of Health Stroke Scale (NIHSS) (OR 1.484; 95% CI, 1.155–1.907) were significant predictors of the poor outcome of patients with AIS and included into the nomogram model. The nomogram showed good calibration and discrimination. C-index was 0.891 (95% CI, 0.854–0.928). DCA confirmed the clinical usefulness of the model. The dynamic nomogram can be obtained at the website: https://odywong.shinyapps.io/DBT_21/.ConclusionThe dynamic nomogram, comprised of glycosylated hemoglobin, ASPECTS, and NIHSS score at day 14, may be able to predict the 3-month unfavorable outcome for AIS patients.

Outcome prediction in large vessel occlusion ischemic stroke with or without endovascular stroke treatment: THRIVE-EVT.

The THRIVE score and the THRIVE-c calculation are validated ischemic stroke outcome prediction tools based on patient variables that are readily available at initial presentation. Randomized controlled trials (RCTs) have demonstrated the benefit of endovascular treatment (EVT) for many patients with large vessel occlusion (LVO), and pooled data from these trials allow for adaptation of the THRIVE-c calculation for use in shared clinical decision making regarding EVT. To extend THRIVE-c for use in the context of EVT, we extracted data from the Virtual International Stroke Trials Archive (VISTA) from 7 RCTs of EVT. Models were built in a randomly selected development cohort using logistic regression that included the predictors from THRIVE-c: age, NIH Stroke Scale (NIHSS) score, presence of hypertension, diabetes mellitus, and/or atrial fibrillation, as well as randomization to EVT and, where available, the Alberta Stroke Program Early CT Score (ASPECTS). Good outcome was achieved in 366/787 (46.5%) of subjects randomized to EVT and in 236/795 (29.7%) of subjects randomized to control (P < 0.001), and the improvement in outcome with EVT was seen across age, NIHSS, and THRIVE-c good outcome prediction. Models to predict outcome using THRIVE elements (age, NIHSS, and comorbidities) together with EVT, with or without ASPECTS, had similar performance by ROC analysis in the development and validation cohorts (THRIVE-EVT ROC area under the curve (AUC) = 0.716 in development, 0.727 in validation, P = 0.30; THRIVE-EVT + ASPECTS ROC AUC = 0.718 in development, 0.735 in validation, P = 0.12). THRIVE-EVT may be used alongside the original THRIVE-c calculation to improve outcome probability estimation for patients with acute ischemic stroke, including patients with or without LVO, and to model the potential improvement in outcomes with EVT for an individual patient based on variables that are available at initial presentation. Online calculators for THRIVE-c estimation are available at www.thrivescore.org and www.mdcalc.com/thrive-score-for-stroke-outcome.