Favorable Collaterals Research Articles

Transcoronary Gradients of Mechanosensitive MicroRNAs as Predictors of Collateral Development in Chronic Total Occlusion.

Background and Objectives: In this present study, we investigated the impact of mechanosensitive microRNAs (mechano-miRs) on the collateral development in 126 chronic total occlusion (CTO) patients, selected from 810 undergoing angiography. Materials and Methods: We quantified the collateral blood supply using the collateral flow index (CFI) and assessed the transcoronary mechano-miR gradients. Results: The patients with favorable collaterals had higher CFI values (0.45 ± 0.02) than those with poor collaterals (0.38 ± 0.03, p < 0.001). Significant differences in transcoronary gradients were found for miR-10a, miR-19a, miR-21, miR-23b, miR-26a, miR-92a, miR-126, miR-130a, miR-663, and let7d (p < 0.05). miR-26a and miR-21 showed strong positive correlations with the CFI (r = 0.715 and r = 0.663, respectively), while let7d and miR-663 were negatively correlated (r = -0.684 and r = -0.604, respectively). The correlations between cytokine gradients and mechano-miR gradients were also significant, including Transforming Growth Factor Beta with miR-126 (r = 0.673, p < 0.001) and Vascular Endothelial Growth Factor with miR-10a (r = 0.602, p = 0.002). A regression analysis highlighted the hemoglobin level, smoking, beta-blocker use, miR-26a, and miR-663 as significant CFI determinants, indicating their roles in modulating the collateral vessel development. Conclusions: These findings suggest mechanosensitive microRNAs as predictive biomarkers for collateral circulation, offering new therapeutic perspectives for CTO patients.

The risk and outcome of malignant brain edema in post-mechanical thrombectomy: acute ischemic stroke by anterior circulation occlusion

Background and purposeMalignant brain edema (MBE) occurring after mechanical thrombectomy (MT) in acute ischemic stroke (AIS) could lead to severe disability and mortality. We aimed to investigate the incidence, predictors, and clinical outcomes of MBE in patients with AIS after MT.MethodsThe clinical and imaging data of 155 patients with AIS of anterior circulation after MT were studied. Standard non-contrast CT was used to evaluate baseline imaging characteristics at admission. Clinical outcomes were measured using the 90-day modified Rankin Scale (mRS) score. Based on the follow-up CT scans performed within 72 h after MT, the patients were classified into MBE and non-MBE group. MBE was defined as a midline shift of ≥ 5 mm with signs of local brain swelling. Univariate and multivariate regression analyses were used to analyze the relationship between MBE and clinical outcomes and identify the predictors that correlate with MBE.ResultsMBE was observed in 19.4% of the patients who underwent MT and was associated with a lower rate of favorable 90-day clinical outcomes. Significant differences were observed in both MBE and non-MBE groups: baseline Alberta Stroke Program Early CT (ASPECT) score, hyperdense middle cerebral artery sign (HMCAS), baseline signs of early infarct, angiographic favorable collaterals, number of retrieval attempts, and revascularization rate. Multivariate analysis indicated that low baseline ASPECT score, absent HMCAS, angiographic poor collaterals, more retrieval attempt count, and poor revascularization independently influenced the occurrence of MBE in AIS patients with anterior circulation after MT.ConclusionMBE was associated with a lower rate of favorable 90-day clinical outcomes. Low baseline ASPECT score, absent HMCAS, angiographic poor collaterals, more retrieval attempt count and poor revascularization were independently associated with MBE after MT.

Abstract WP115: DWI/FLAIR Mismatch Is Common In Late Window Patients With Target Perfusion Mismatch

Introduction: The presence of a DWI/FLAIR mismatch has been suggested as a method to identify patients within 4.5 hours from stroke symptom onset. We studied patients from DEFUSE 2 and 3 with the target perfusion mismatch profile to evaluate the rates of DWI/FLAIR mismatch in patients with who have favorable collaterals in early and late time windows. We hypothesize that the persistence of DWI/FLAIR mismatch in late window patients may reflect good collateral circulation. Methods: We identified 58 eligible patients in D2 and 30 patients from D3. Imaging was reviewed by two neuroradiologists and one neurologist who rated the presence of DWI-FLAIR mismatch. Results: The inter-rater agreement for the presence of DWI/FLAIR mismatch was 88.3%. There were 32 patients who were &lt; 6 hours from last known well (LKW) or symptom onset, 17 patients who were ≥ 6 hours from symptom onset, and 26 patients who were ≥ 6 hours from LKW with an unknown time of symptom onset. These are categorized as early, late, and suspected late window, respectively. The rate of DWI/FLAIR mismatch was 56% in the early window group, 41% in the late window group, and 35% in the suspected late window group. The overall rate of DWI/FLAIR mismatch did not differ significantly between these three groups (56% vs. 41% vs. 35%, p=0.239). Of the early window patients, the rate of DWI-FLAIR mismatch was higher in those with the target perfusion mismatch profile (67%) compared to those without (36%). All but one the known onset late window patients had the target perfusion mismatch profile, and the rate of DWI-FLAIR mismatch in this group was 35%. Forthcoming analyses will include predictors of DWI-FLAIR mismatch such as hypoperfusion intensity ratio, time from symptom onset, and NIHSS score. Conclusions: More than one-third of patients presenting &gt;6 hours from symptom onset with a target perfusion mismatch profile have DWI/FLAIR mismatch. This could reflect the presence of good collateral circulation that may delay the appearance of a FLAIR lesion. The rate of DWI/FLAIR mismatch did not differ among early, late, and expected late window patients. This suggests that, among patients with favorable collaterals, DWI/FLAIR mismatch does not reliably identify early window patients.

Early plasma D-dimer as a predictor of acute intracranial atherosclerosis-related large vessel occlusion in acute ischemic stroke.

Intracranial atherosclerosis-related large vessel occlusion (ICAS+LVO) poses an important technical challenge for endovascular thrombectomy (EVT). To evaluate the value of D-dimer in predicting ICAS+LVO alone and in combination with other clinical and imaging predictors. Consecutive patients who underwent EVT at our center between January 2018 and June 2021 were retrospectively reviewed. Patients were classified to the ICAS+LVO or ICAS-LVO group according to angiographic findings. Collateral gradings were evaluated based on computed tomography angiography and categorized as follows: score 0-1 unfavorable collaterals and score 2-3 favorable collaterals. Receiver operating characteristic curve was analyzed to evaluate the predictive value of D-dimer and the combination of other predictors for ICAS+LVO. A total of 374 patients were enrolled, among them, 107 (28.6%) had an ICAS+LVO, while ICAS-LVO was determined in 267 (71.4%) patients. Median D-dimer levels were lower (0.36 vs. 1.18 mg/L; P < 0.001) while the proportion of favorable collaterals was higher (85.0% vs. 22.5%; P < 0.001) in the ICAS+LVO group than the ICAS-LVO group. After multivariable analysis, D-dimer (adjusted odds ratio [OR]=0.32, 95% confidence interval [CI]=0.21-0.50; P < 0.001) and collaterals (adjusted OR=16.25, 95% CI=7.58-34.84; P < 0.001) remained independent predictors of ICAS+LVO. The area under the curve of D-dimer, collaterals, and combination for identification of ICAS+LVO was 0.82, 0.85, and 0.92, respectively. Low early plasma D-dimer levels are a significant and independent predictor of ICAS+LVO, and predictive value strengthens when in a combined model using D-dimer and collateral grading.

Characterizing Fast and Slow Progressors in Anterior Circulation Large Vessel Occlusion Strokes.

Infarct growth rate (IGR) in acute ischemic stroke is highly variable. We sought to evaluate impact of symptom-reperfusion time on outcomes in patients undergoing mechanical thrombectomy (MT). A prospectively maintained database from January,2012-August,2020 was reviewed. All patients with isolated MCA-M1 occlusion who achieved complete reperfusion(mTICI2C-3), had a witnessed symptom onset and follow-up MRI were included. IGR was calculated as final infarct volume (FIV)(ml)/symptom onset to reperfusion time(hours) and was dichotomized according to the median value into slow-(SP) versus fast-progressors (FP). The primary analysis aimed to evaluate the impact of symptom-reperfusion time on 90-day mRS in SP and FP. Secondary analysis was performed to identify predictors of IGR. A total of 137 patients were eligible for analysis. Mean age was 63 ± 15.4 years and median IGR was 5.13ml/hour. SP(n = 69) had higher median ASPECTS, lower median rCBF<30% lesion volume, higher proportion of favorable collaterals and hypoperfusion intensity ratio (HIR)<0.4, higher minimal mean arterial blood pressure before reperfusion, and lower rates of general anesthesia compared to FP(n = 68). Symptom-reperfusion time was comparable between both groups. SP had higher rates of 90-day mRS0-2(71.9%vs.38.9%,aOR;7.226,95%CI[2.431-21.482],p < 0.001) and lower median FIV. Symptom-reperfusion time was associated with 90-day mRS0-2 in FP (aOR;0.541,95%CI[0.309-0.946],p = 0.03) but not in SP (aOR;0.874,95%CI[0.742-1.056],p = 0.16). On multivariable analysis, high ASPECTS and favorable collaterals in the NCCT/CTA model, and low rCBF<30% and HIR<0.4 in the CTP model were independent predictors of SP. The impact of symptom-reperfusion time on outcomes significantly varies across slow-versus fast-progressors. ASPECTS, collateral score, rCBF<30%, and HIR define stroke progression profile.

Cerebrovascular Collateral Integrity in Pediatric Large Vessel Occlusion: Analysis of the Save ChildS Study.

Robust cerebrovascular collaterals in adult patients with large vessel occlusion stroke have been associated with longer treatment windows, better recanalization rates, and improved outcomes, but the role of collaterals in pediatric stroke is not known. The primary aim was to determine whether favorable collaterals correlated with better radiographic and clinical outcomes in children with ischemic stroke who underwent thrombectomy. This study analyzed a subset of children enrolled in SaveChildS, a retrospective, multicenter, observational cohort study of 73 pediatric patients with stroke who underwent thrombectomy between 2000 and 2018 at 27 US and European centers. Included patients had baseline angiographic imaging and follow-up modified Rankin Scale scores available for review. Posterior circulation occlusions were excluded. Cerebrovascular collaterals were graded on acute neuroimaging by 2 blinded neuroradiologists according to the Tan collateral score, in which favorable collaterals are defined as >50% filling and unfavorable collaterals as <50% filling distal to the occluded vessel. Collateral status was correlated with clinical and neuroimaging characteristics and outcomes. Between-group comparisons were performed with the Wilcoxon rank-sum test for continuous variables or Fisher exact test for binary variables. Thirty-three children (mean age 10.9 [SD ±4.9]) years were included; 14 (42.4%) had favorable collaterals. Median final stroke volume as a percent of total brain volume (TBV) was significantly lower in patients with favorable collaterals (1.35% [interquartile range (IQR) 1.14%-3.76%] vs 7.86% [IQR 1.54%-11.07%], p = 0.049). Collateral status did not correlate with clinical outcome, infarct growth, or final Alberta Stroke Program Early CT Score (ASPECTS) in our cohort. Patients with favorable collaterals had higher baseline ASPECTS (7 [IQR 6-8] vs 5.5 [4-6], p = 0.006), smaller baseline ischemic volume (1.57% TBV [IQR 1.09%-2.29%] vs 3.42% TBV [IQR 1.26%-5.33%], p = 0.035), and slower early infarct growth rate (2.4 mL/h [IQR 1.5-5.1 mL/h] vs 10.4 mL/h [IQR 3.0-30.7 mL/h], p = 0.028). Favorable collaterals were associated with smaller final stroke burden and slower early infarct growth rate but not with better clinical outcome in our study. Prospective studies are needed to determine the impact of collaterals in childhood stroke. This study provides Class II evidence that in children with ischemic stroke undergoing thrombectomy, favorable collaterals were associated with improved radiographic outcomes but not with better clinical outcomes.

Effect of Oxygen Extraction (Brush-Sign) on Baseline Core Infarct Depends on Collaterals (HIR).

Objectives: Baseline-core-infarct volume is a critical factor in patient selection and outcome in acute ischemic stroke (AIS) before mechanical thrombectomy (MT). We determined whether oxygen extraction efficiency and arterial collaterals, two different physiologic components of the cerebral ischemic cascade, interacted to modulate baseline-core-infarct volume in patients with AIS-LVO undergoing MT triage.Methods: Between January 2015 and March 2018, consecutive patients with an AIS and M1 occlusion considered for MT with a baseline MRI and perfusion-imaging were included. Variables such as baseline-core-infarct volume [mL], arterial collaterals (HIR: TMax > 10 s volume/TMax > 6 s), high oxygen extraction (HOE, presence of the brush-sign on T2*) were assessed. A linear-regression was used to test the interaction of HOE and HIR with baseline-core-infarct volume, after including potential confounding variables.Results: We included 103 patients. Median age was 70 (58–78), and 63% were female. Median baseline-core-infarct volume was 32 ml (IQR 8–74.5). Seventy six patients (74%) had HOE. In a multivariate analysis both favorable HIR collaterals (p = 0.02) and HOE (p = 0.038) were associated with lower baseline-core-infarct volume. However, HOE significantly interacted with HIR (p = 0.01) to predict baseline-core-infarct volume, favorable collaterals (low HIR) with HOE was associated with small baseline-core-infarct whereas patients with poor collaterals (high HIR) and HOE had large baseline-core-infarct.Conclusion: While HOE under effective collateral blood-flow has the lowest baseline-core-infarct volume of all patients, the protective effect of HOE reverses under poor collateral blood-flow and may be a maladaptive response to ischemic stroke as measured by core infarctions in AIS-LVO patients undergoing MT triage.

Large Vessel Occlusion Strokes After the DIRECT-MT and SKIP Trials: Is the Alteplase Syringe Half Empty or Half Full?

Large Vessel Occlusion Strokes After the DIRECT-MT and SKIP Trials: Is the Alteplase Syringe Half Empty or Half Full?

Relationship between stroke etiology and collateral status in anterior circulation large vessel occlusion

Background and purposeClinical outcome after mechanical thrombectomy (MT) for large vessel occlusion (LVO) stroke is influenced by the intracerebral collateral status. We tested the hypothesis that patients with preexisting ipsilateral extracranial carotid artery stenosis (CAS) would have a better collateral status compared to non-CAS patients. Additionally, we evaluated MT-related adverse events and outcome for both groups.MethodsOver a 7-year period, we identified all consecutive anterior circulation MT patients (excluding extracranial carotid artery occlusion and dissection). Patients were grouped into those with CAS ≥ 50% according to the NASCET criteria and those without significant carotid stenosis (non-CAS). Collateral status was rated on pre-treatment CT- or MR-angiography according to the Tan Score. Furthermore, we assessed postinterventional infarct size, adverse events and functional outcome at 90 days.ResultsWe studied 281 LVO stroke patients, comprising 46 (16.4%) with underlying CAS ≥ 50%. Compared to non-CAS stroke patients (n = 235), patients with CAS-related stroke more often had favorable collaterals (76.1% vs. 46.0%). Recanalization rates were comparable between both groups. LVO stroke patients with underlying CAS more frequently had adverse events after MT (19.6% vs. 6.4%). Preexisting CAS was an independent predictor for favorable collateral status in multivariable models (Odds ratio: 3.3, p = 0.002), but post-interventional infarct size and functional 90-day outcome were not different between CAS and non-CAS patients.ConclusionsPreexisting CAS ≥ 50% was associated with better collateral status in LVO stroke patients. However, functional 90-day outcome was independent from CAS, which could be related to a higher rate of adverse events.

Atrial Fibrillation Treatment Adequacy and Outcome after Endovascular Thrombectomy

BackgroundAtrial fibrillation (AF) often leads to large vessel occlusions (LVO) which may necessitate endovascular thrombectomy (EVT). Whether the adequacy of treatment with oral anticoagulants (OAC) prior to LVO modifies outcomes remains unknown. Patients and MethodsConsecutive EVT-treated LVO patients were recruited and the data was analyzed retrospectively. We combined patients with known AF that were untreated with OAC or inadequately treated with those with new-onset AF to form a group of undertreated-AF patients and compared them to adequately treated AF patients. ResultsOf the 230 patients included, 109 (47%) had AF (86 known AF, 23 new-onset AF). AF patients were significantly older and more often reached favorable recanalization but less often had favorable outcomes compared to those without AF. Most patients with known AF (76%) were inadequately treated at stroke onset. Patients with undertreated-AF more often received tPA prior to EVT (26% vs. 4% p=0.009), more often had favorable collaterals (65% vs. 33% p<0.001) and more often reached favorable outcomes (28% vs. 9%, p=0.047) compared to adequately treated AF patients. On multivariate analyses adequately treated AF did not impact survival (Odds Ration [OR] 0.89 95% Confidence Interval [CI] 0.23-3.43), chances for favorable recanalization (OR 0.57 95%CI 0.15-2.13) or favorable outcome (OR 5.95 95%CI 0.62-57.39). ConclusionsTreatment adequacy does not affect the rates of favorable functional outcome or survival in AF patients with LVO.

Collateral status contributes to differences between observed and predicted 24-h infarct volumes in DEFUSE 3

We previously demonstrated that in the DEFUSE 3 trial, the union of the baseline core and the 24-h Tmax > 6 s perfusion lesion predicts the infarct volume at 24 h. Presently, we assessed if collateral robustness measured by the hypoperfusion intensity ratio (HIR) and cerebral blood volume (CBV) index accounts for the variance in these predictions. DEFUSE 3 patients underwent MRI/CT perfusion imaging at baseline and 24 h post-randomization. We compared baseline and follow-up HIR and CBV index across subgroups stratified by differences between predicted and observed 24-h infarct volumes. Of 123 eligible patients, 34 with 24-h infarcts larger than predicted had less favorable collaterals at baseline (HIR 0.43 vs. 0.32, p = 0.006; CBV Index 0.78 vs. 0.85, p = 0.001) and 24 h (HIR 0.56 vs. 0.07, p = 0.004; CBV Index 0.47 vs. 0.73, p = 0.006) compared to 71 patients with more accurate infarct volume prediction. Eighteen patients with 24-h infarcts smaller than predicted had similar baseline collateral scores but more favorable 24-h CBV indices (0.81 vs. 0.73, p = 0.040). Overall, patients with 24-h infarcts larger than predicted had evidence of less favorable baseline collaterals that fail within 24 h, while patients with 24-h infarcts smaller than predicted typically had favorable collaterals that persisted for 24 h.

Abstract WMP24: Collateral Status Contributes to Differences Between Observed and Predicted 24-Hour Infarct Volumes in DEFUSE 3

Background and Purpose: We have previously shown that in the DEFUSE 3 trial, the infarct volume 24 hours after randomization was predicted by the union of the baseline core and the 24-hour Tmax&gt;6s perfusion lesion. We determined if collateral robustness measured by the hypoperfusion intensity ratio (HIR) and cerebral blood volume index (CBV) accounts for the variance in infarct volume predictions. Methods: DEFUSE 3 patients underwent MRI with perfusion or CT perfusion at baseline and 24 hours after randomization. We used RAPID software to determine ischemic core and Tmax&gt;6s lesion volumes as well as HIR and CBV Index at baseline and 24 hours. Patients were stratified by the difference between the predicted and the observed infarct volume at 24 hours. We compared baseline and follow-up HIR and CBV Index, as well as several other imaging and clinical outcomes in subgroups based on the accuracy of the infarct volume estimate. Results: Out of 123 eligible patients, 34 had 24-hour infarcts larger than predicted and these patients had less favorable collaterals (HIR 0.43 vs 0.32, p=0.006 and CBV Index 0.78 vs 0.85, p=0.001) at baseline, as well as at 24-hour follow-up (HIR 0.56 vs 0.07, p=0.004 and CBV Index 0.47 vs 0.73, p=0.006) compared to the 71 patients with more accurate infarct volume prediction. The remaining 18 patients had 24-hour infarct volumes smaller than predicted. These patients had similar baseline collateral scores but a more favorable CBV Index at 24 hours (0.81 vs 0.73, p=0.040) compared to patients with more accurate infarct prediction. Conclusions: Patients with 24-hour infarcts larger than predicted had evidence of less favorable baseline collaterals that fail within 24 hours, while patients with 24-hour infarcts smaller than predicted typically had favorable collaterals that persisted for at least 24 hours. Clinical Trial Registration: URL: http://www.clinicaltrials.gov. Unique identifier: NCT02586415

Hypoperfusion Intensity Ratio Is Correlated With Patient Eligibility for Thrombectomy.

Background and Purpose- Hypoperfusion intensity ratio (HIR) is associated with collateral status in acute ischemic stroke patients with anterior circulation large vessel occlusion. We assessed whether HIR was correlated to patient eligibility for mechanical thrombectomy (MT). Methods- We performed a retrospective cohort study of consecutive acute ischemic stroke patients with a proximal middle cerebral artery or internal carotid artery occlusion who underwent MT triage with computed tomography or magnetic resonance perfusion imaging. Clinical data, ischemic core (mL), HIR (defined as time-to-maximum [TMax] >10 seconds/TMax >6 seconds), mismatch volume between core and penumbra, and MT details were assessed. Primary outcome was favorable HIR collateral score (HIR <0.4) between patients who underwent MT (MT+) and those who did not (MT-) according to American Heart Association guidelines both in the <6 hours and 6 to 24 hours windows. Secondary outcomes were favorable HIR score in MT- subgroups (National Institutes of Health Stroke Scale <6 versus core >70 mL) and core-penumbra mismatch volumes. Patients who did not meet guidelines were not included. Results- We included 197 patients (145 MT+ and 52 MT-). MT+ patients had a significantly lower median HIR compared with MT- patients (0.4 [interquartile range, 0.2-0.5] versus 0.6 [interquartile range, 0.5-0.8]; P<0.001) and a higher mismatch volume (96 versus 27 mL, P<0.001). Among MT- patients, 43 had a core >70 mL, and 9 had a National Institutes of Health Stroke Scale <6. MT- patients with National Institutes of Health Stroke Scale <6 had a lower HIR than MT- patients with core >70 mL (0.2 [interquartile range, 0.2-0.3] versus 0.7 [interquartile range, 0.6-0.8], P<0.001) but their HIR was not significantly different that MT+ patients. Conclusions- Patients who meet American Heart Association guidelines for thrombectomy are more likely to have favorable collaterals (low HIR). HIR may be used as a marker of eligibility for MT triage.

Persistent Target Mismatch Profile >24 Hours After Stroke Onset in DEFUSE 3.

Background and Purpose- Efficacy of endovascular thrombectomy has been demonstrated up to 24 hours after stroke onset in patients selected with perfusion imaging. We hypothesized that a persistent favorable perfusion profile exists in some patients beyond 24 hours from the onset and can be predicted by a lower baseline hypoperfusion intensity ratio, which indicates favorable collaterals. Methods- We identified control arm patients from the DEFUSE 3 trial (The Endovascular Therapy Following Imaging Evaluation for Ischemic Stroke) with a diffusion weighted imaging and perfusion magnetic resonance imaging performed 24 hours following randomization and compared imaging and clinical variables between patients with persistent mismatch versus patients who no longer had a mismatch 24 hours after randomization. Results- Eighteen percent of the control arm patients had a persistent favorable profile >38 hours after last known well time. These patients had similar baseline diffusion weighted imaging and Tmax >6 seconds volumes as patients whose initially favorable perfusion profile became unfavorable (diffusion weighted imaging lesion 7 versus 17 mL; P=0.17, Tmax >6 seconds 98 versus 100 mL; P=0.48) yet experienced less infarct growth (15 versus 59 mL; P<0.001) and had 3-fold smaller infarct volumes (15 versus 59 mL; P<0.001) 24 hours after randomization. Patients with a persistent favorable perfusion profile had a significantly lower hypoperfusion intensity ratio on baseline imaging (0.2 versus 0.4; P<0.01). Favorable clinical outcome at 90 days occurred in only 10% of the persistent mismatch patients. Conclusions- About 20% of patients with a middle cerebral artery or internal carotid artery occlusion who present in an extended time window and are not treated with thrombectomy have a persistent mismatch for at least an additional 24 hours. These patients have a favorable hypoperfusion intensity ratio at presentation, may experience delayed infarct expansion, and have poor clinical outcomes. Clinical trials are needed to determine if patients with a favorable perfusion profile benefit from reperfusion beyond 24 hours. Clinical Trial Registration- URL: https://www.clinicaltrials.gov . Unique identifier: NCT02586415.

Abstract WP6: Successful Mechanical Thrombectomy Maybe Associated With Reduced Disability in Patients With Large Core Based on CTP: The Forsaken Cannot be Forgotten

Background and Purpose: There is disparity on neuroimaging selection for acute stroke thrombectomy. Patients with large core infarcts are often excluded from reperfusion therapies. We aim to assess rates of favorable clinical outcomes in patients with large cores based on CTP (RAPID) and the effect of collaterals in this population. Methods: Retrospective study of patients with ischemic cores greater than 50cc on CTP and a proximal anterior circulation occlusion on computed tomographic angiogram who underwent endovascular thrombectomy. Evaluation period was October 2015 to June 2018 on three comprehensive stroke centers. Baseline characteristics, ASPECTS and collaterals scores were evaluated. Primary endpoint was rate of favorable clinical outcome at 3 months. Results: 45 patients were included in the study. Mean age was 65 ±14.2 years, mean NIHSS score was 20 (10-32) and mean admission infarct volume was 85±31mL (CBF &lt;30%) and Tmax&gt;6 s was 199.5±68mL. The majority of patients presented within 6 hours (82%). Median ASPECTS score was 8 and 33% of patients had a favorable collaterals. Recanalization thrombolysis in cerebral ischemia 2b-3 was 88%. Post-thrombectomy mean infarct volume at 24 to 48 hours was 107±68.3mL, A total of 42% (19/45) had tPA. A 3-month favorable clinical outcome (mRS 0-2) was present in 31% (14/45) of patients. Rate of intracranial hemorrhage (ph1 or ph2) was 11% (5/45). A total of 92% (13/14) of all patients older than 75 years had a poor clinical outcome (mRS score &gt;2). Among patients with good collaterals 46% (7/15) had good clinical outcomes whereas 23% (7/30) of patients with poor collaterals score had good clinical outcomes at 3 months. The rate of good outcome at three months for patients with ASPECTS&gt; 6 was 31% (11/35), while 41% of patients with both favorable ASPECTS and Collaterals had a good clinical outcome. Hemicraniectomy was performed in 4% (2/45) of all patients. Conclusions: Acute stroke thrombectomy may be beneficial in some patients with large core based on CTP with good collaterals and it should not be withhold solely based on the core infarct volume on CTP in patients presenting within 6 hours.

Abstract 165: CT Perfusion Collateral Score Predicts Which Patients Will Maintain a Penumbral Profile on MRI for Greater than 24 Hours

Introduction: The DAWN and DEFUSE 3 trials demonstrated efficacy of endovascular treatment in patients selected using perfusion imaging or MR Diffusion Weighted Imaging (DWI) and treated up to 24h after stroke onset. Hypothesis: We hypothesized that a persistent favorable perfusion profile (target mismatch, which indicates the presence of penumbral tissue) exists in some patients beyond 24h from onset and can be predicted by lower baseline hypoperfusion intensity ratio (HIR, proportion of Tmax &gt;6s lesion having &gt;10s delay), which indicates favorable collaterals. Methods: We identified control arm patients from the DEFUSE 3 trial with a DWI and perfusion MRI performed 24h following randomization and defined 3 subgroups: Group 1) patients with spontaneous reperfusion; Group 2) persistent hypoperfusion lesion, but loss of the target mismatch perfusion profile; Group 3) persistent target mismatch profile. We compared group 2 with group 3 in terms of baseline, 24h and clinical outcome variables. Results: 55/90 patients in the medical arm had DWI and perfusion MRI follow-up imaging 24 hours after randomization and were included. 18% had spontaneous reperfusion, 64% had a persisting Tmax lesion with an unfavorable profile, and 18% had a persistent target mismatch profile. Patients with a persistent target mismatch profile had a significantly lower HIR on baseline imaging (0.2 vs 0.4, p&lt;0.01) and significantly less infarct growth (15mL vs 59mL, p&lt;0.001) than patients with loss of the target mismatch profile. The persistent target mismatch was documented a median of 38 hours after last known well time. There was no association between baseline clinical characteristics or clinical outcomes and a persistent favorable profile. Conclusions: Approximately 20% of medical arm patients in DEFUSE 3 had a persistent mismatch at a median of 38 hours after stroke onset. These patients have very slowly expanding infarcts but eventually suffer very poor clinical outcomes. Clinical trials are needed to determine if late patients presenting with penumbral tissue benefit from thrombectomy more than 24 hours from symptom onset.

Vision Outcomes of Endovascular Treatment for Unruptured Ophthalmic Artery Aneurysms

The purpose of this study was to report the authors' experience with endovascular treatment (EVT) of ophthalmic artery (OA) aneurysms and to investigate risk factors for visual complications of EVT for unruptured OA aneurysms. Fifty-four patients with unruptured OA aneurysms subjected to EVT were recruited for this study from March 2010 to December 2017. The clinical and angiographic outcomes of all 54 patients were investigated and analyzed retrospectively. Of the 54 patients included in this study, 5 patients (9.3%) had visual complications, including asymptomatic unintended OA occlusion in 2 patients (3.7%) and symptomatic complications in 3 patients (5.6%); 2 patients (3.7%) had transient visual complications, and 1 (1.9%) had a permanent complication. No subacute or delayed visual complications occurred during the 20.8-month follow-up period. OA incorporation by the aneurysm (odds ratio [OR], 3.471; 95% confidence interval [CI], 1.115-9.184; P= 0.038) and intentional OA occlusion (OR, 1.820; 95% CI, 1.248-6.221; P= 0.044) were independent risk factors for visual complications in a multivariate logistic regression analysis. The visual complication rate was 9.3% when performing EVT for unruptured OA aneurysms. OA aneurysms with OA incorporation by the aneurysm might be at higher risk of visual complications when performing EVT. Intentional OA occlusion should be performed with caution, even though a patient may have favorable collaterals during balloon test occlusion.

Abstract TP5: Mr Predicts a Reliable and Useful Tool in Identifying Benefit of Mechanical Thrombectomy in Patients With Large Vessel Occlusion

Background: The AHA/ASA guideline recommends endovascular therapy for patients with acute ischemic stroke within 6 hours from symptom onset. Identification of the patients most likely to benefit (and those most likely to be harmed) from reperfusion plays a pivotal role in decision-making. We applied the MR PREDICTS tool (clinical decision making tool derived from MR CLEAN clinical trial) on a real-world sample of patients with acute ischemic stroke to assess its utility in predicting clinical benefit from endovascular therapy. Methods: We identified all patients with acute ischemic stroke with occlusion of the distal internal carotid artery, proximal M1, or M2 segment of the middle cerebral artery who underwent endovascular reperfusion procedure (thrombectomy and/or intra-arterial thrombolysis) from July 2016 to June 2017. Patients were divided into two groups; those with a good outcome (90 Day mRS 0-2) and those with a poor outcome (90 Day mRS 3-6). The MR PREDICTS tool was used to determine absolute treatment benefit for each patient. This predicted outcome was compared to actual patient outcome. Results: A total of 22 patients were identified. Eight patients had a good outcome and 14 patients had a poor outcome. The calculated absolute treatment benefit from endovascular therapy using the MR PREDICTS tool was consistently higher among patients in the good outcome group, with an average absolute treatment benefit of 12% greater among these patients compared to those in the poor outcome cohort (19% versus 7%). Of note, patients with a poor outcome had a higher rate of prior stroke, higher baseline NIHSS, longer symptom onset to groin puncture time, less favorable collaterals and lower rate of successful recanalization defined as TICI 2b or 3 (100% versus 64%). Conclusion: There is a strong correlation between predicted treatment benefit by MR PREDICTS tool and actual patient outcomes which supports broader use of this tool during the decision-making process for endovascular therapy in patients with acute ischemic stroke.

Collaterals Predict Outcome Regardless of Time Last Known Normal

Recent studies suggest that patients with large-vessel ischemic strokes (large-vessel occlusion [LVO]) with favorable imaging may benefit from mechanical thrombolysis even when treated outside the standard 6-hour window. However, many patients in these studies presented with unknown times of onset. We compare outcomes in thrombectomy patients treated at less than versus greater than 6 hours from last known well (LKN), and evaluate whether "unknown time of onset" alters prognosis. We retrospectively reviewed patients at 2 comprehensive stroke centers. Student's t and chi-square tests evaluated the association between predetermined clinical and radiographic variables, including unknown time of onset, and outcome (discharge and follow-up National Institutes of Health Stroke Scale score and modified Rankin Scale [mRS] score) for LVOs treated after greater than 6 hours versus 6 hours or less from LKN. Multivariable logistic regression was used to determine the odds of good outcome (mRS score 0-2). A total of 113 patients were treated over 2 years; 31 were treated at greater than 6 hours. Those who were treated at greater than 6 hours and experienced poor outcomes were more likely to have large-artery atherosclerosis (P = .033). There was no difference in outcome for patients outside the window with known (39.1%) versus unknown (60.9%) time of onset. mRS scores at discharge were higher among those outside the window (odds ratio 3.78; 95% confidence interval 1.20-11.89) but not at follow-up. After multivariable regression, favorable collaterals alone were associated with a mRS score of 0-2. When imaging is favorable, the mRS score at follow-up is comparable regardless of time LKN. Functional outcomes appear to be driven most significantly by the presence of collaterals.