Impact of Intracranial Volume and Brain Volume on the Prognostic Value of Computed Tomography Perfusion Core Volume in Acute Ischemic Stroke.

BACKGROUND: Computed tomography perfusion (CTP)-estimated core volume is associated with functional outcomes in acute ischemic stroke. This relationship might differ among patients, depending on brain volume. MATERIALS AND METHODS: We retrospectively included patients from the MR CLEAN Registry. Cerebrospinal fluid (CSF) and intracranial volume (ICV) were automatically segmented on NCCT. We defined the proportion of the ICV and total brain volume (TBV) affected by the ischemic core as ICVcore and TBVcore. Associations between the core volume, ICVcore, TBVcore, and functional outcome are reported per interquartile range (IQR). We calculated the area under the curve (AUC) to assess diagnostic accuracy. RESULTS: In 200 patients, the median core volume was 13 (5-41) mL. Median ICV and TBV were 1377 (1283-1456) mL and 1108 (1020-1197) mL. Median ICVcore and TBVcore were 0.9 (0.4-2.8)% and 1.7 (0.5-3.6)%. Core volume (acOR per IQR 0.48 [95%CI 0.33-0.69]), ICVcore (acOR per IQR 0.50 [95%CI 0.35-0.69]), and TBVcore (acOR per IQR 0.41 95%CI 0.33-0.67]) showed a lower likelihood of achieving improved functional outcomes after 90 days. The AUC was 0.80 for the prediction of functional independence at 90 days for the CTP-estimated core volume, the ICVcore, and the TBVcore. CONCLUSION: Correcting the CTP-estimated core volume for the intracranial or total brain volume did not improve the association with functional outcomes in patients who underwent EVT.

Sex differences in outcomes after endovascular treatment in posterior circulation stroke: results from the MR CLEAN Registry.

BACKGROUND: Women with anterior circulation large vessel occlusion (LVO) have been reported to have worse outcomes after endovascular treatment (EVT) than men. Whether these disparities also exist in LVO of the posterior circulation is yet uncertain. We assessed sex differences in clinical, technical, and safety outcomes of EVT in posterior circulation LVO. METHODS: We used data of patients with posterior circulation LVO included in the Multicenter Randomized Clinical Trial of Endovascular Treatment for Acute Ischemic Stroke in the Netherlands (MR CLEAN) Registry (2014-2018). Primary outcome was the modified Rankin Scale (mRS) score at 90 days assessed with multivariable ordinal regression analysis. Secondary outcomes included favorable functional outcome (mRS ≤3), functional independence (mRS ≤2), death within 90 days, National Institutes of Health Stroke Scale (NIHSS) score 24-48 hours postintervention, complications, successful reperfusion (extended Thrombolysis in Cerebral Ischemia 2B-3), and procedure duration analyzed with multivariable logistic and linear regression analyses. RESULTS: We included 264 patients (42% women). Compared with men, women were older (median age 68 vs 63 years), more often had prestroke disability (mRS ≥1: 37% vs 30%), and received intravenous thrombolytics less often (45% vs 56%). Clinical outcomes were similar between sexes (adjusted (common) OR (aOR) 0.82, 95% CI 0.51 to 1.34; favorable functional outcome 50% vs 43%, aOR 1.31, 95% CI 0.77 to 2.25; death 32% vs 29%, aOR 0.98, 95% CI 0.52 to 1.84). In addition, NIHSS score after 24-48 hours (median 7 vs 9), successful reperfusion (77% vs 73%), and complications did not differ between men and women. CONCLUSIONS: Outcomes in women treated with EVT for posterior circulation LVO were similar compared with men despite less favorable baseline characteristics in women. Therefore men and women may benefit equally from EVT.

Endovascular treatment of patients with stroke caused by anterior cerebral artery occlusions.

BACKGROUND: Occlusion of the anterior cerebral artery (ACA) is uncommon but may lead to significant disability. The benefit of endovascular treatment (EVT) for ACA occlusions remains uncertain. METHODS: We included patients treated with EVT and compared patients with ACA occlusions with patients who had internal carotid artery (ICA) or proximal (M1/M2) middle cerebral artery (MCA) occlusions from the MR CLEAN Registry. Primary outcome was the modified Rankin Scale score (mRS). Secondary outcomes were functional independence (mRS 0-2), National Institutes of Health Stroke Scale (NIHSS) score, delta-NIHSS (baseline minus NIHSS score at 24-48 h), and successful recanalization (expanded thrombolysis in cerebral infarction (eTICI) score 2b-3). Safety outcomes were symptomatic intracranial hemorrhage (sICH), periprocedural complications, and mortality. RESULTS: Of 5193 patients, 11 (0.2%) had primary ACA occlusions. Median NIHSS at baseline was lower in patients with ACA versus ICA/MCA occlusions (11, IQR 9-14; versus 15, IQR 11-19). Functional outcome did not differ from patients with ICA/MCA occlusions. Functional independence was 4/11 (36%) in patients with ACA versus 1949/4815 (41%) in ICA/MCA occlusions; median delta-NIHSS was - 1 (IQR - 7 to 2) and - 4 (IQR - 9 to 0), respectively. Successful recanalization was 4/9 (44%), versus 3083/4787 (64%) in ICA/MCA occlusions. Mortality was 3/11 (27%) versus 1263/4815 (26%). One patient with ACA occlusion had sICH; no other complications occurred. CONCLUSION: In this cohort ACA occlusions were uncommon. Functional outcome did not differ between patients with ACA occlusions and ICA/MCA occlusions. Prospective research is needed to determine feasibility, safety, and outcomes of EVT for ACA occlusions.

Comparison of Prehospital Assessment by Paramedics and In-Hospital Assessment by Physicians in Suspected Stroke Patients: Results From 2 Prospective Cohort Studies.

BACKGROUND: It is unknown if ambulance paramedics adequately assess neurological deficits used for prehospital stroke scales to detect anterior large-vessel occlusions. We aimed to compare prehospital assessment of these stroke-related deficits by paramedics with in-hospital assessment by physicians. METHODS: We used data from 2 prospective cohort studies: the LPSS (Leiden Prehospital Stroke Study) and PRESTO study (Prehospital Triage of Patients With Suspected Stroke). In both studies, paramedics scored 9 neurological deficits in stroke code patients in the field. Trained physicians scored the National Institutes of Health Stroke Scale (NIHSS) at hospital presentation. Patients with transient ischemic attack were excluded because of the transient nature of symptoms. Spearman rank correlation coefficient (rs) was used to assess correlation between the total prehospital assessment score, defined as the sum of all prehospital items, and the total NIHSS score. Correlation, sensitivity and specificity were calculated for each prehospital item with the corresponding NIHSS item as reference. RESULTS: We included 2850 stroke code patients. Of these, 1528 had ischemic stroke, 243 intracranial hemorrhage, and 1079 stroke mimics. Correlation between the total prehospital assessment score and NIHSS score was strong (rs=0.70 [95% CI, 0.68-0.72]). Concerning individual items, prehospital assessment of arm (rs=0.68) and leg (rs=0.64) motor function correlated strongest with corresponding NIHSS items, and had highest sensitivity (arm 95%, leg 93%) and moderate specificity (arm 71%, leg 70%). Neglect (rs=0.31), abnormal speech (rs=0.50), and gaze deviation (rs=0.51) had weakest correlations. Neglect and gaze deviation had lowest sensitivity (52% and 66%) but high specificity (84% and 89%), while abnormal speech had high sensitivity (85%) but lowest specificity (65%). CONCLUSIONS: The overall prehospital assessment of stroke code patients correlates strongly with in-hospital assessment. Prehospital assessment of neglect, abnormal speech, and gaze deviation differed most from in-hospital assessment. Focused training on these deficits may improve prehospital triage.

Alternative Arterial Access Routes for Endovascular Thrombectomy in Patients with Acute Ischemic Stroke: A Study from the MR CLEAN Registry.

Background: Endovascular thrombectomy (EVT) through femoral access is difficult to perform in some patients with acute ischemic stroke due to challenging vasculature. We compared outcomes of EVT through femoral versus alternative arterial access. Methods: In this observational study, we included patients from the MR CLEAN Registry who underwent EVT for acute ischemic stroke in the anterior circulation between 2014 and 2019 in the Netherlands. Patients who underwent EVT through alternative and femoral access were matched on propensity scores in a 1:3 ratio. The primary endpoint was favorable functional outcome (modified Rankin Scale score ≤ 2) at 90 days. Secondary endpoints were early neurologic recovery, mortality, successful intracranial reperfusion and puncture related complications. Results: Of the 5197 included patients, 17 patients underwent EVT through alternative access and were matched to 48 patients who underwent EVT through femoral access. Alternative access was obtained through the common carotid artery (n = 15/17) and brachial artery (n = 2/17). Favorable functional outcome was less often observed after EVT through alternative than femoral access (18% versus 27%; aOR, 0.36; 95% CI, 0.05-2.74). The rate of successful intracranial reperfusion was higher for alternative than femoral access (88% versus 58%), although mortality (59% versus 31%) and puncture related complications (29% versus 0%) were more common after alternative access. Conclusions: EVT through alternative arterial access is rarely performed in the Netherlands and seems to be associated with worse outcomes than standard femoral access. A next step would be to compare the additional value of EVT through alternative arterial access after failure of femoral access.

Prehospital Stroke Triage: A Modeling Study on the Impact of Triage Tools in Different Regions.

BACKGROUND AND PURPOSE: Direct transportation to a thrombectomy-capable intervention center is beneficial for patients with ischemic stroke due to large vessel occlusion (LVO), but can delay intravenous thrombolytics (IVT). The aim of this modeling study was to estimate the effect of prehospital triage strategies on treatment delays and overtriage in different regions. METHODS: We used data from two prospective cohort studies in the Netherlands: the Leiden Prehospital Stroke Study and the PRESTO study. We included stroke code patients within 6 h from symptom onset. We modeled outcomes of Rapid Arterial oCclusion Evaluation (RACE) scale triage and triage with a personalized decision tool, using drip-and-ship as reference. Main outcomes were overtriage (stroke code patients incorrectly triaged to an intervention center), reduced delay to endovascular thrombectomy (EVT), and delay to IVT. RESULTS: We included 1798 stroke code patients from four ambulance regions. Per region, overtriage ranged from 1-13% (RACE triage) and 3-15% (personalized tool). Reduction of delay to EVT varied by region between 24 ± 5 min (n = 6) to 78 ± 3 (n = 2), while IVT delay increased with 5 (n = 5) to 15 min (n = 21) for non-LVO patients. The personalized tool reduced delay to EVT for more patients (25 ± 4 min [n = 8] to 49 ± 13 [n = 5]), while delaying IVT with 3-14 min (8-24 patients). In region C, most EVT patients were treated faster (reduction of delay to EVT 31 ± 6 min (n = 35), with RACE triage and the personalized tool. CONCLUSIONS: In this modeling study, we showed that prehospital triage reduced time to EVT without disproportionate IVT delay, compared to a drip-and-ship strategy. The effect of triage strategies and the associated overtriage varied between regions. Implementation of prehospital triage should therefore be considered on a regional level.

Endovascular treatment versus no endovascular treatment after 6-24 h in patients with ischaemic stroke and collateral flow on CT angiography (MR CLEAN-LATE) in the Netherlands: a multicentre, open-label, blinded-endpoint, randomised, controlled, phase 3 trial.

BACKGROUND: Endovascular treatment for anterior circulation ischaemic stroke is effective and safe within a 6 h window. MR CLEAN-LATE aimed to assess efficacy and safety of endovascular treatment for patients treated in the late window (6-24 h from symptom onset or last seen well) selected on the basis of the presence of collateral flow on CT angiography (CTA). METHODS: MR CLEAN-LATE was a multicentre, open-label, blinded-endpoint, randomised, controlled, phase 3 trial done in 18 stroke intervention centres in the Netherlands. Patients aged 18 years or older with ischaemic stroke, presenting in the late window with an anterior circulation large-vessel occlusion and collateral flow on CTA, and a neurological deficit score of at least 2 on the National Institutes of Health Stroke Scale were included. Patients who were eligible for late-window endovascular treatment were treated according to national guidelines (based on clinical and perfusion imaging criteria derived from the DAWN and DEFUSE-3 trials) and excluded from MR CLEAN-LATE enrolment. Patients were randomly assigned (1:1) to receive endovascular treatment or no endovascular treatment (control), in addition to best medical treatment. Randomisation was web based, with block sizes ranging from eight to 20, and stratified by centre. The primary outcome was the modified Rankin Scale (mRS) score at 90 days after randomisation. Safety outcomes included all-cause mortality at 90 days after randomisation and symptomatic intracranial haemorrhage. All randomly assigned patients who provided deferred consent or died before consent could be obtained comprised the modified intention-to-treat population, in which the primary and safety outcomes were assessed. Analyses were adjusted for predefined confounders. Treatment effect was estimated with ordinal logistic regression and reported as an adjusted common odds ratio (OR) with a 95% CI. This trial was registered with the ISRCTN, ISRCTN19922220. FINDINGS: Between Feb 2, 2018, and Jan 27, 2022, 535 patients were randomly assigned, and 502 (94%) patients provided deferred consent or died before consent was obtained (255 in the endovascular treatment group and 247 in the control group; 261 [52%] females). The median mRS score at 90 days was lower in the endovascular treatment group than in the control group (3 [IQR 2-5] vs 4 [2-6]), and we observed a shift towards better outcomes on the mRS for the endovascular treatment group (adjusted common OR 1·67 [95% CI 1·20-2·32]). All-cause mortality did not differ significantly between groups (62 [24%] of 255 patients vs 74 [30%] of 247 patients; adjusted OR 0·72 [95% CI 0·44-1·18]). Symptomatic intracranial haemorrhage occurred more often in the endovascular treatment group than in the control group (17 [7%] vs four [2%]; adjusted OR 4·59 [95% CI 1·49-14·10]). INTERPRETATION: In this study, endovascular treatment was efficacious and safe for patients with ischaemic stroke caused by an anterior circulation large-vessel occlusion who presented 6-24 h from onset or last seen well, and who were selected on the basis of the presence of collateral flow on CTA. Selection of patients for endovascular treatment in the late window could be primarily based on the presence of collateral flow. FUNDING: Collaboration for New Treatments of Acute Stroke consortium, Dutch Heart Foundation, Stryker, Medtronic, Cerenovus, Top Sector Life Sciences & Health, and the Netherlands Brain Foundation.

Admission systolic blood pressure and effect of endovascular treatment in patients with ischaemic stroke: an individual patient data meta-analysis.

BACKGROUND: Current guidelines for ischaemic stroke treatment recommend a strict, but arbitrary, upper threshold of 185/110 mm Hg for blood pressure before endovascular thrombectomy. Nevertheless, whether admission blood pressure influences the effect of endovascular thrombectomy on outcome remains unknown. Our aim was to study the influence of admission systolic blood pressure (SBP) on functional outcome and on the effect of endovascular thrombectomy. METHODS: We used individual patient data from seven randomised controlled trials (MR CLEAN, ESCAPE, EXTEND-IA, SWIFT PRIME, REVASCAT, PISTE, and THRACE) that randomly assigned patients with anterior circulation ischaemic stroke to endovascular thrombectomy (predominantly using stent retrievers) or standard medical therapy (control) between June 1, 2010, and April 30, 2015. We included all patients for whom SBP data were available at hospital admission. The primary outcome was functional outcome (modified Rankin Scale) at 90 days. We assessed the association of SBP with outcome in both the endovascular thrombectomy group and the control group using multilevel regression analysis and tested for non-linearity and for interaction between SBP and effect of endovascular thrombectomy, taking into account treatment with intravenous thrombolysis. FINDINGS: We included 1753 patients (867 assigned to endovascular thrombectomy, 886 assigned to control) after excluding 11 patients for whom SBP data were missing. We found a non-linear association between SBP and functional outcome with an inflection point at 140 mm Hg (732 [42%] of 1753 patients had SBP <140 mm Hg and 1021 [58%] had SBP ≥140 mm Hg). Among patients with SBP of 140 mm Hg or higher, admission SBP was associated with worse functional outcome (adjusted common odds ratio [acOR] 0·86 per 10 mm Hg SBP increase; 95% CI 0·81-0·91). We found no association between SBP and functional outcome in patients with SBP less than 140 mm Hg (acOR 0·97 per 10 mm Hg SBP decrease, 95% CI 0·88-1·05). There was no significant interaction between SBP and effect of endovascular thrombectomy on functional outcome (p=0·96). INTERPRETATION: In our meta-analysis, high admission SBP was associated with worse functional outcome after stroke, but SBP did not seem to negate the effect of endovascular thrombectomy. This finding suggests that admission SBP should not form the basis for decisions to withhold or delay endovascular thrombectomy for ischaemic stroke, but randomised trials are needed to further investigate this possibility. FUNDING: Medtronic.

Association between thrombus composition and stroke etiology in the MR CLEAN Registry biobank.

PURPOSE: The composition of thrombi retrieved during endovascular thrombectomy (EVT) in acute ischemic stroke (AIS) due to large vessel occlusion (LVO) may differ depending on their origin. In this study, we investigated the association between thrombus composition and stroke etiology in a large population of patients from the Dutch MR CLEAN Registry treated with EVT in daily clinical practice. METHODS: The thrombi of 332 patients with AIS were histologically analyzed for red blood cells (RBC), fibrin/platelets (F/P), and white blood cells (leukocytes) using a machine learning algorithm. Stroke etiology was assessed using the Trial of Org 10,172 in acute stroke treatment (TOAST) classification. RESULTS: The thrombi of cardioembolic origin contained less RBC and more F/P than those of non-cardioembolic origin (25.8% vs 41.2% RBC [p = 0.003] and 67.1% vs 54.5% F/P [p = 0.004]). The likelihood of a non-cardioembolic source of stroke increased with increasing thrombus RBC content (OR 1.02; [95% CI 1.00-1.06] for each percent increase) and decreased with a higher F/P content (OR 1.02; [95% CI 1.00-1.06]). Thrombus composition in patients with a cardioembolic origin and undetermined origin was similar. CONCLUSION: Thrombus composition is significantly associated with stroke etiology, with an increase in RBC and a decrease in F/P raising the odds for a non-cardioembolic cause. No difference between composition of cardioembolic thrombi and of undetermined origin was seen. This emphasizes the need for more extensive monitoring for arrhythmias and/or extended cardiac analysis in case of an undetermined origin.

Sex differences in onset to hospital arrival time, prestroke disability, and clinical symptoms in patients with a large vessel occlusion: a MR CLEAN Registry substudy.

BACKGROUND: Women have been reported to have worse outcomes after endovascular treatment (EVT), despite a similar treatment effect in non-clinical trial populations. We aimed to assess sex differences at hospital presentation with respect to workflow metrics, prestroke disability, and presenting clinical symptoms. METHODS: We included consecutive patients from the Multicentre Randomised Controlled Trial of Endovascular Treatment for Acute Ischaemic Stroke in The Netherlands (MR CLEAN) Registry (2014-2018) who received EVT for anterior circulation large vessel occlusion (LVO). We assessed sex differences in workflow metrics, prestroke disability (modified Rankin Scale (mRS) score ≥1), and stroke severity and symptoms according to the National Institutes of Health Stroke Scale (NIHSS) score on hospital admission with logistic and linear regression analyses and calculated the adjusted OR (aOR). RESULTS: We included 4872 patients (47.6% women). Compared with men, women were older (median age 76 vs 70 years) and less often achieved good functional outcome at 90 days (mRS ≤2: 35.2% vs 46.4%, aOR 0.70, 95% CI 0.60 to 0.82). Mean onset-to-door time was longer in women (2 hours 16 min vs 2 hours 7 min, adjusted delay 9 min, 95% CI 4 to 13). This delay contributed to longer onset-to-groin times (3 hours 26 min in women vs 3 hours 13 min in men, adjusted delay 13 min, 95% CI 9 to 17). Women more often had prestroke disability (mRS ≥1: 41.1% vs 29.1%, aOR 1.57, 95% CI 1.36 to 1.82). NIHSS on admission was essentially similar in men and women (mean 15±6 vs 15±6, NIHSS <10 vs ≥10, aOR 0.91, 95% CI 0.78 to 1.06). There were no clear sex differences in the occurrence of specific stroke symptoms. CONCLUSION: Women with LVO had longer onset-to-door times and more often prestroke disability than men. Raising awareness of these differences at hospital presentation and investigating underlying causes may help to improve outcome after EVT in women.

Collateral status and recanalization after endovascular treatment for acute ischemic stroke.

BACKGROUND: Successful recanalization and good collateral status are associated with good clinical outcomes after endovascular treatment (EVT) for acute ischemic stroke, but the relationships among them are unclear. OBJECTIVE: To assess if collateral status is associated with recanalization after EVT and if collateral status modifies the association between successful recanalization and functional outcome. METHODS: We retrospectively analyzed data from the MR CLEAN Registry, a multicenter prospective cohort study of patients with a proximal anterior occlusion who underwent EVT in the Netherlands. We determined collateral status with a previously validated four-point visual grading scale and defined successful recanalization as an extended Thrombolysis in Cerebral Infarction score ≥2B. Functional outcome was determined using the modified Rankin Scale score at 90 days. We assessed, with multivariable logistic regression models, the associations between (1) collateral status and successful recanalization, (2) successful recanalization and functional outcome, (3) collateral status and functional outcome. An interaction of collateral status and successful recanalization was assessed. Subgroup analyses were performed for patients treated with intravenous thrombolysis. RESULTS: We included 2717 patients, of whom 1898 (70%) had successful recanalization. There was no relationship between collateral status and successful recanalization (adjusted common OR (95% CI) of grades 1, 2, and 3 vs 0: 1.19 (0.82 to 1.72), 1.20 (0.83 to 1.75), and 1.10 (0.74 to 1.63), respectively). Successful recanalization (acOR (95% CI): 2.15 (1.84 to 2.52)) and better collateral grades (acOR (95% CI) of grades 1, 2, and 3 vs 0: 2.12 (1.47 to 3.05), 3.46 (2.43 to 4.92), and 4.16 (2.89 to 5.99), respectively) were both associated with a shift towards better functional outcome, without an interaction between collateral status and successful recanalization. Results were similar for the subgroup of thrombolysed patients. CONCLUSIONS: Collateral status is not associated with the probability of successful recanalization after EVT and does not modify the association between successful recanalization and functional outcome.

Successful reperfusion in relation to the number of passes: comparing outcomes of first pass expanded Treatment In Cerebral Ischemia (eTICI) 2B with multiple-pass eTICI 3.

BACKGROUND: Higher expanded Treatment In Cerebral Ischemia (eTICI) reperfusion scores after endovascular treatment (EVT) are associated with better outcomes. However, the influence of the number of passes on this association is unclear. We aimed to compare outcomes of single-pass good reperfusion (eTICI 2B) with multiple-pass excellent/complete reperfusion (eTICI 2C/3) in daily clinical practice. METHODS: We compared outcomes of patients in the MR CLEAN Registry with good reperfusion (eTICI 2B) in a single pass to those with excellent/complete reperfusion (eTICI 2C/3) in multiple passes. Regression models were used to investigate the association of single-pass eTICI 2B versus multiple-pass eTICI 2C/3 reperfusion with 90-day functional outcome (modified Rankin Scale (mRS)), functional independence (mRS 0-2), per-procedural complications and safety outcomes. RESULTS: We included 699 patients: 178 patients with single-pass eTICI 2B, and 242 and 279 patients with eTICI 2C/3 after 2 and ≥3 passes, respectively. Patients with eTICI 2C/3 after 2 or ≥3 passes did not achieve significantly better functional outcomes compared with patients with single-pass eTICI 2B (adjusted common OR (acOR) 1.06, 95% CI 0.75 to 1.50 and acOR 0.88, 95% CI 0.74 to 1.05 for 90-day mRS, and adjusted OR (aOR) 1.24, 95% CI 0.78 to 1.97 and aOR 0.79, 95% CI 0.52 to 1.22 for functional independence). CONCLUSIONS: Our results did not show better outcomes for patients who achieved eTICI 2C/3 in multiple, that is, two or more, passes when compared with patients with single-pass eTICI 2B. However, this concerns observational data. Further research is necessary to investigate the per-pass effect in relation to reperfusion and functional outcome.

Endovascular treatment for isolated posterior cerebral artery occlusion stroke in the MR CLEAN registry.

BACKGROUND: Endovascular treatment (EVT) is standard of care in anterior circulation large vessel occlusions. In posterior circulation occlusions, data on EVT in isolated posterior cerebral artery (PCA) occlusions are limited, although PCA occlusions can cause severe neurological deficit. OBJECTIVE: To describe in a prospective study the clinical manifestations, outcomes, and safety of EVT in isolated PCA occlusions. METHODS: We used data (2014-2017) from the MR CLEAN Registry, a nationwide, prospective cohort of EVT-treated patients in the Netherlands. We included patients with acute ischemic stroke (AIS) due to an isolated PCA occlusion on CT angiography. Patients with concurrent occlusion of the basilar artery were excluded. Outcomes included change in National Institutes of Health Stroke Scale (ΔNIHSS) score, modified Rankin Scale (mRS) score 0-3 after 90 days, mortality, expanded Thrombolysis in Cerebral Infarction (eTICI), and periprocedural complications. RESULTS: Twenty (12%) of 162 patients with posterior circulation occlusions had an isolated PCA occlusion. Median age was 72 years; 13 (65%) were women. Median baseline NIHSS score was 13 (IQR 5-21). Six (30%) patients were comatose. Twelve patients (60%) received IVT. Median ΔNIHSS was -4 (IQR -11-+1). At follow-up, nine patients (45%) had mRS score 0-3. Seven (35%) died. eTICI 2b-3 was achieved in 13 patients (65%). Nine patients (45%) had periprocedural complications. No symptomatic intracranial hemorrhages (sICH) occurred. CONCLUSIONS: EVT should be considered in selected patients with AIS with an isolated PCA occlusion, presenting with moderate-severe neurological deficits, as EVT was technically feasible in most of our patients and about half had good clinical outcome. In case of lower NIHSS score, a more conservative approach seems warranted, since periprocedural complications are not uncommon. Nonetheless, EVT seems reasonably safe considering the absence of sICH in our study.

Timing of symptomatic intracranial hemorrhage after endovascular stroke treatment.

Introduction: Little is known about the timing of occurrence of symptomatic intracranial hemorrhage (sICH) after endovascular therapy (EVT) for acute ischemic stroke. A better understanding could optimize in-hospital surveillance time points and duration. The aim of this study was to delineate the probability of sICH over time and to identify factors associated with its timing. Patients and methods: We retrospectively analyzed data from the Dutch MR CLEAN trial and MR CLEAN Registry. We included adult patients who underwent EVT for an anterior circulation large vessel occlusion within 6.5 h of stroke onset. In patients with sICH (defined as ICH causing an increase of ⩾4 points on the National Institutes of Health Stroke Scale [NIHSS]), univariable and multivariable linear regression analysis was used to identify factors associated with the timing of sICH. This was defined as the time between end of EVT and the time of first CT-scan on which ICH was seen as a proxy. Results: SICH occurred in 205 (6%) of 3391 included patients. Median time from end of EVT procedure to sICH detection on NCCT was 9.0 [IQR 2.9-22.5] hours, with a rapidly decreasing incidence after 24 h. None of the analyzed factors, including baseline NIHSS, intravenous alteplase treatment, and poor reperfusion at the end of the procedure were associated with the timing of sICH. Conclusion: SICHs primarily occur in the first hours after EVT, and less frequently beyond 24 h. Guidelines that recommend to perform frequent neurological assessments for at least 24 h after intravenous alteplase treatment can be applied to ischemic stroke patients treated with EVT.

Development of the SAFETEA Scores for Predicting Risks of Complications of Preventive Endovascular or Microneurosurgical Intracranial Aneurysm Occlusion.

OBJECTIVE: Preventive unruptured intracranial aneurysm occlusion can reduce the risk of subarachnoid hemorrhage, but both endovascular and microneurosurgical treatment carry a risk of serious complications. To improve individualized management decisions, we developed risk scores for complications of endovascular and microneurosurgical treatment based on easily retrievable patient, aneurysm, and treatment characteristics. METHODS: For this multicenter cohort study, we combined individual patient data from unruptured intracranial aneurysm patients ≥18 years undergoing preventive endovascular treatment (standard, balloon-assisted or stent-assisted coiling, Woven EndoBridge-device, or flow-diverting stent) or microneurosurgical clipping at one of 10 participating centers from three continents between 2000-2018. The primary outcome was death from any cause or clinical deterioration from neurological complications ≤30 days. We selected predictors based on previous knowledge about relevant risk factors and predictor performance and studied the association between predictors and complications with logistic regression. We assessed model performance with calibration plots and concordance (c) statistics. RESULTS: Of 1282 included patients, 94 (7.3%) had neurological symptoms that resolved <30 days, 140 (10.9%) had persisting neurological symptoms, and 6 died (0.5%)). At 30 days, 52 patients (4.1%) were dead or dependent. Predictors of procedural complications were: size of aneurysm, aneurysm location, familial subarachnoid hemorrhage, earlier atherosclerotic disease, treatment volume, endovascular modality (for endovascular treatment) or extra aneurysm configuration factors (for microneurosurgical treatment; branching artery from aneurysm neck or unfavorable dome-to-neck ratio), and age (acronym: SAFETEA). For endovascular treatment (n=752), the c-statistic was 0.72 (95%CI:0.67-0.77) and the absolute complication risk ranged from 3.2% (95%CI:1.6%-14.9%;≤1 point) to 33.1% (95%CI:25.4%-41.5%;≥6 points). For microneurosurgical treatment (n=530), the c-statistic was 0.72 (95%CI:0.67-0.77) and the complication risk ranged from 4.9% (95%CI:1.5%-14.9%;≤1 point) to 49.9% (95%CI:39.4%-60.6%;≥6 points). CONCLUSIONS: The SAFETEA risk scores for endovascular and microneurosurgical treatment are based on seven easily retrievable risk factors to predict the absolute risk of procedural complications in patients with unruptured intracranial aneurysms. The scores need external validation before the predicted risks can be properly used to support decision making in clinical practice.

Evaluating the Diagnostic Performance of Prehospital Stroke Scales Across the Range of Deficit Severity: Analysis of the Prehospital Triage of Patients With Suspected Stroke Study.

BACKGROUND: The usefulness of prehospital scales for identifying anterior circulation large vessel occlusion (aLVO) in patients with suspected stroke may vary depending on the severity of their presentation. The performance of these scales across the spectrum of deficit severity is unclear. The aim of this study was to evaluate the diagnostic performance of 8 prehospital scales for identifying aLVO across the spectrum of deficit severity. METHODS: We used data from the PRESTO study (Prehospital Triage of Patients With Suspected Stroke Symptoms), a prospective observational study comparing prehospital stroke scales in detecting aLVO in suspected stroke patients. We used the National Institutes of Health Stroke Scale (NIHSS) score, assessed in-hospital, as a proxy for the Clinical Global Impression of stroke severity during prehospital assessment by paramedics. We calculated the sensitivity, specificity, positive predictive value, negative predictive value, and the difference in aLVO probabilities with a positive or negative prehospital scale test (ΔPaLVO) for each scale for mild (NIHSS 0-4), intermediate (NIHSS 5-9), moderate (NIHSS 10-14), and severe deficits (NIHSS≥15). RESULTS: Among 1033 patients with suspected stroke, 119 (11.5%) had an aLVO, of whom 19 (16.0%) had mild, 25 (21.0%) had intermediate, 30 (25.2%) had moderate, and 45 (37.8%) had severe deficits. The scales had low sensitivity and positive predictive value in patients with mild-intermediate deficits, and poor specificity, negative predictive value, and accuracy with moderate-severe deficits. Positive results achieved the highest ΔPaLVO in patients with mild deficits. Negative results achieved the highest ΔPaLVO with severe deficits, but the probability of aLVO with a negative result in the severe range was higher than with a positive test in the mild range. CONCLUSIONS: Commonly-used prehospital stroke scales show variable performance across the range of deficit severity. Probability of aLVO remains high with a negative test in severely affected patients. Studies reporting prehospital stroke scale performance should be appraised in the context of the NIHSS distribution of their samples.

Safety and efficacy of periprocedural antithrombotics in patients with successful reperfusion after endovascular stroke treatment.

OBJECTIVES: We aimed to evaluate whether the overall harmful effect of periprocedural treatment with aspirin or heparin during endovascular stroke treatment is different in patients with a successful reperfusion after the procedure. MATERIALS AND METHODS: We performed a post-hoc analysis of the MR CLEAN-MED trial, including adult patients with a large vessel occlusion in the anterior circulation eligible for endovascular treatment (EVT). In this trial, patients were randomized for periprocedural intravenous treatment with aspirin or no aspirin (1:1 ratio), and for moderate-dose unfractionated heparin, low-dose unfractionated heparin or no unfractionated heparin (1:1:1 ratio). We tested for interaction between the post-EVT extended thrombolysis in cerebral infarction (eTICI) score and treatment with periprocedural medication with multivariable regression analyses. The primary outcome was the modified Rankin Scale score at 90 days. Secondary outcomes were final infarct volume, intracranial hemorrhage, and symptomatic intracranial hemorrhage. RESULTS: Of 534 included patients, 93 (17%) had a post-EVT eTICI score of 0-2a, 115 (22%) a score of 2b, 73 (14%) a score of 2c, and 253 (47%) a score of 3. For both aspirin and heparin, we found no interaction between post-EVT eTICI score and treatment on the modified Rankin Scale score (p=0.76 and p=0.47, respectively). We found an interaction between post-EVT eTICI score and treatment with heparin on the final infarct volume (p=0.01). Of note, this interaction showed a biologically implausible distribution over the subgroups. CONCLUSIONS: The overall harmful effect of periprocedural aspirin and unfractionated heparin is not different in patients with a successful reperfusion after EVT.

Deep-Learning-Based Thrombus Localization and Segmentation in Patients with Posterior Circulation Stroke.

Thrombus volume in posterior circulation stroke (PCS) has been associated with outcome, through recanalization. Manual thrombus segmentation is impractical for large scale analysis of image characteristics. Hence, in this study we develop the first automatic method for thrombus localization and segmentation on CT in patients with PCS. In this multi-center retrospective study, 187 patients with PCS from the MR CLEAN Registry were included. We developed a convolutional neural network (CNN) that segments thrombi and restricts the volume-of-interest (VOI) to the brainstem (Polar-UNet). Furthermore, we reduced false positive localization by removing small-volume objects, referred to as volume-based removal (VBR). Polar-UNet is benchmarked against a CNN that does not restrict the VOI (BL-UNet). Performance metrics included the intra-class correlation coefficient (ICC) between automated and manually segmented thrombus volumes, the thrombus localization precision and recall, and the Dice coefficient. The majority of the thrombi were localized. Without VBR, Polar-UNet achieved a thrombus localization recall of 0.82, versus 0.78 achieved by BL-UNet. This high recall was accompanied by a low precision of 0.14 and 0.09. VBR improved precision to 0.65 and 0.56 for Polar-UNet and BL-UNet, respectively, with a small reduction in recall to 0.75 and 0.69. The Dice coefficient achieved by Polar-UNet was 0.44, versus 0.38 achieved by BL-UNet with VBR. Both methods achieved ICCs of 0.41 (95% CI: 0.27-0.54). Restricting the VOI to the brainstem improved the thrombus localization precision, recall, and segmentation overlap compared to the benchmark. VBR improved thrombus localization precision but lowered recall.

Surveillance of Unruptured Intracranial Aneurysms: Cost-Effectiveness Analysis for 3 Countries.

BACKGROUND AND OBJECTIVES: No consensus exists on adequate surveillance of conservatively managed unruptured intracranial aneurysms (UIAs). We aimed to determine optimal MRI surveillance strategies for the growth of UIAs using cost-effectiveness analysis. A secondary aim was to develop a clinical tool for personalizing UIA surveillance. METHODS: We designed a microsimulation model from a health care perspective simulating 100,000 55-year-old women to estimate costs and quality-adjusted life years (QALYs) over a lifetime horizon in the United States, the United Kingdom, and the Netherlands, using literature-derived model parameters. Country-specific costs and willingness-to-pay thresholds ($100,000/QALY for the United States, £30,000/QALY for the United Kingdom, and €80,000/QALY for the Netherlands) were used. Lifetime costs and QALYs were annually discounted at 3% for the United States, 3.5% for the United Kingdom, or 4% (costs) and 1.5% (QALYs) for the Netherlands. Strategies were no follow-up surveillance, follow-up with MRI in the first and fifth year after UIA discovery, every 5 years, every 2 years, or annually, or immediate intervention (i.e., clipping or coiling). Using the microsimulation model, we developed a tool for personalizing UIA surveillance for men and women, with different ages and varying aneurysm characteristics. Uncertainty in the input parameters was modeled with probabilistic sensitivity analysis. RESULTS: Among 55-year-old women, 2,222 individuals in the United States, 1,910 in the United Kingdom, and 2,040 in the Netherlands needed to undergo an annual MRI scan to prevent 1 case of subarachnoid hemorrhage per year. No surveillance MRI was most cost-effective in the United States (in 47% of the simulations) and United Kingdom (in 54% of simulations), whereas annual MRI was most cost-effective in the Netherlands (in 53% of simulations). In the United States and United Kingdom, annual surveillance or surveillance in the first and fifth year after discovery was cost-effective in patients <60 years and at increased risk of aneurysm growth. The optimal, personalized, surveillance strategies were summarized in a look-up table for use in clinical practice. DISCUSSION: Generally, the US and UK physicians should refrain from assigning patients, particularly older patients and those with few risk factors for aneurysm growth or rupture, to frequent MRI surveillance. In the Netherlands, annual follow-up is generally most cost-effective.