Low Baseline Ischemic Water Uptake is Directly Related to Overestimation of CT Perfusion-Derived Ischemic Core Volume

Abstract Background Computed-tomography perfusion (CTP) is frequently used to screen acute ischemic stroke (AIS) patients for endovascular treatment (EVT), despite known problems with ischemic “core” overestimation. This potentially leads to the unfair exclusion of patients from EVT. We propose that net water uptake (NWU) can be used in addition to CTP to more accurately assess the extent and/or stage of tissue infarction. Methods Patients treated for AIS between 06/2015-07/2020 were retrospectively analyzed. Baseline CTP-derived core volume (pCore) and NWU were determined. Logistic regression tested the relationship between baseline clinical and imaging variables and core-overestimation (primary outcome). The secondary outcomes comprised 90-day functional independence (modified Rankin score) and lesion growth. Results 284 patients were included. Median NWU was 7.2% (IQR:2.6–12.8). ASPECTS (RR:1.28,95%CI:1.09-1.51), NWU (RR:0.94,95%CI:0.89-0.98), onset to recanalization (RR:1.00,95%CI:0.99-1.00) and imaging (RR:1.00,95%CI1.00-1.00) times, and pCore (RR:1.02,95%CI:1.01-1.02) were significantly associated with core overestimation. Core-overestimation was more likely to occur in patients with large pCores and low NWU at baseline. NWU was significantly correlated with lesion growth. Conclusion NWU can be used as a supplemental tool to CTP during admission imaging to more accurately assess the extent of ischemia, particularly relevant for patients with large CTP-defined cores who would otherwise be excluded from treatment.

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Ischemic lesion growth in acute stroke: Water uptake quantification distinguishes between edema and tissue infarct

Journal of Cerebral Blood Flow & Metabolism ◽

10.1177/0271678x19848505 ◽

2019 ◽

Vol 40 (4) ◽

pp. 823-832 ◽

Cited By ~ 5

Author(s):

Gabriel Broocks ◽

Uta Hanning ◽

Tobias D Faizy ◽

Alexandra Scheibel ◽

Jawed Nawabi ◽

...

Keyword(s):

Water Uptake ◽

Treatment Effects ◽

Vasogenic Edema ◽

Outcome Variable ◽

Lesion Volume ◽

Ischemic Lesion ◽

Lesion Growth ◽

The Mean ◽

Ischemic Core ◽

Core Volume

Infarct growth from the early ischemic core to the total infarct lesion volume (LV) is often used as an outcome variable of treatment effects, but can be overestimated due to vasogenic edema. The purpose of this study was (1) to assess two components of early lesion growth by distinguishing between water uptake and true net infarct growth and (2) to investigate potential treatment effects on edema-corrected net lesion growth. Sixty-two M1-MCA-stroke patients with acute multimodal and follow-up CT (FCT) were included. Ischemic lesion growth was calculated by subtracting the initial CTP-derived ischemic core volume from the LV in the FCT. To determine edema-corrected net lesion growth, net water uptake of the ischemic lesion on FCT was quantified and subtracted from the volume of uncorrected lesion growth. The mean lesion growth without edema correction was 20.4 mL (95% CI: 8.2–32.5 mL). The mean net lesion growth after edema correction was 7.3 mL (95% CI: −2.1–16.7 mL; p < 0.0001). Lesion growth was significantly overestimated due to ischemic edema when determined in early-FCT imaging. In 18 patients, LV was lower than the initial ischemic core volume by CTP. These apparently “reversible” core lesions were more likely in patients with shorter times from symptom onset to imaging and higher recanalization rates.

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Abstract P331: Accuracy of CT Perfusion Core Estimates for Predicting Infarct Size in the SELECT Study

Stroke ◽

10.1161/str.52.suppl_1.p331 ◽

2021 ◽

Vol 52 (Suppl_1) ◽

Author(s):

Amrou Sarraj ◽

Bruce Campbell ◽

Clark Sitton ◽

Soren Christensen ◽

Shekhar Khanpara ◽

...

Keyword(s):

Cohort Study ◽

White Matter ◽

Infarct Size ◽

Ct Perfusion ◽

Infarct Volume ◽

Estimation Accuracy ◽

Ct Perfusion Imaging ◽

Ischemic Core ◽

The Difference ◽

Core Volume

Background: The accuracy of CT perfusion imaging for estimating the ischemic core has been questioned. Methods: In SELECT, a prospective cohort study of imaging selection, pts who achieved complete reperfusion after EVT were stratified on time from LKW to imaging acquisition and time from imaging to reperfusion. The difference between baseline CTP core volume and f/up infarct volume (on DWI after EVT) was classified as over-estimation (core >10 cc larger than infarct), adequate, or under-estimation (≥ 25 cc smaller). F/up DWI lesion was outlined using a semiautomated algorithm and co-registered to CTP. Results: Of 361 enrolled, 117 achieved TICI 3. F/up MRIs were acquired at 21 (13-30) hrs from EVT with median infarct volume of 16.4 cc, median 8.1 cc larger than baseline core. Median (IQR) time from imaging acquisition to groin puncture (GP) was 70 (50-95) min. Reperfusion was achieved at 35 (25-54) min of GP. The frequency of overestimation decreased as time LKW to imaging increased: < 90 min 6 (14%), 90 – 270 min 3 (6%) and > 270 min 1 (4%), and adequate estimation increased (< 90 min 21 (50%), 90 – 270 min 32 (65%) and > 270min 19 (73%), p for trend 0.048) Fig 1. Overestimation primarily occurred in pts imaged within 90 min who had short imaging to reperfusion times Fig 2. Volumetric correlation between pre-procedure and f/up imaging improved as LKW time to imaging acquisition increased; Spearman’s ρ: <90 min: 0.41 (p=0.007), 90-270 min: 0.35 (p=0.01), >270 min: 0.79 (p<0.0001). Spatially, overestimation occurred predominantly in white matter juxtacortical areas. Adjusting rCBF threshold from < 30% to < 20% in the 6 pts with overestimation ≤ 90 min from LKW resulted in adequate core estimation in all 6, Fig 3. Conclusion: In patients who achieve reperfusion, the correlation between baseline CTP ischemic core volume and f/up DWI volume improved as time LKW to imaging increased. Core estimation accuracy improved by using the < 20% CBF threshold for patients imaged within 90 minutes of LKW.

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Abstract TP77: Impact of Time and Aspects on Clinical Core Mismatch in Large Vessel Occlusion Strokes

Stroke ◽

10.1161/str.51.suppl_1.tp77 ◽

2020 ◽

Vol 51 (Suppl_1) ◽

Author(s):

Shashvat Desai ◽

Bradley J Molyneaux ◽

Marcelo Rocha ◽

Matthew Starr ◽

Tudor G Jovin ◽

...

Keyword(s):

Patient Selection ◽

Time Window ◽

Ct Perfusion ◽

Large Vessel ◽

Large Vessel Occlusion ◽

Vessel Occlusion ◽

Ct Head ◽

Ischemic Core ◽

The Impact ◽

Core Volume

Introduction: Patient selection for endovascular thrombectomy (EVT) for anterior circulation large vessel occlusion (LVO) strokes in the 6-24-hour time window is dependent on delineating clinical core mismatch (CCM) as defined by DAWN trial criteria. In contrast, patient selection in the early window (0-6 hours) can be performed using ASPECTS on CT head. We aim to determine the prevalence of DAWN-CCM in LVO strokes and the impact of time and ASPECTS. Methods: Retrospective analysis of large vessel occlusion [internal carotid and middle cerebral artery-M1] strokes at a CSC. Consecutive patients who underwent CT perfusion or MRI within 120 minutes of CT head were included in the study (treated and untreated). Ischemic core volume was assessed using RAPID [IschemaView] and ASPECTS using automated ASPECTS [Brainomix]. CCM was defined using DAWN trial criteria [DAWN-CCM: NIHSS ≥10 and core <31 ml, NIHSS ≥20 and core <51 ml]. Results: A total of 116 patients were included. Mean age was 71 ±14 and 62% were females. Mean ischemic core volume and median ASPECTS were 46 ±65 ml and 8 (6-9), respectively. In patients with NIHSS score ≥10 (98), 57% had DAWN-CCM in the 0-24-hour window. Proportion of patients with DAWN-CCM in 6-24-hour window was 70% (6-12 hours), 50% (12-18 hours), and 50% (18-24 hours) [p=0.35]. Proportion of patients with DAWN-CCM by ASPECTS group was 88% (ASPECTS 9-10), 64% (ASPECTS 6-8) and 13% (ASPECTS 0-5) [p=<0.01] (Figure 1). Probability of DAWN-CCM declines by 7% for every 2 hours increase in TLKW to imaging, and by 13% for every 1-point decrease in ASPECTS. Conclusion: Approximately 57% of LVO strokes have clinical core mismatch. LVO strokes with DAWN-CCM decline with increasing time and decreasing ASPECTS. ASPECTS alone may be sufficient to identify patients with DAWN-CCM in a resource limited setting and avoid time consuming advanced imaging.

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Association of collateral status and ischemic core growth in patients with acute ischemic stroke

Neurology ◽

10.1212/wnl.0000000000011258 ◽

2020 ◽

pp. 10.1212/WNL.0000000000011258

Author(s):

Longting Lin ◽

Jianhong Yang ◽

Chushuang Chen ◽

Huiqiao Tian ◽

Andrew Bivard ◽

...

Keyword(s):

Growth Rate ◽

Ischemic Stroke ◽

Acute Ischemic Stroke ◽

Ct Perfusion ◽

Study Cohort ◽

Vessel Occlusion ◽

Ischemic Core ◽

Relationship Of ◽

The Relationship ◽

Linear Regressions

ObjectiveTo test the hypothesis that acute ischemic patients with poorer collaterals would have faster ischemic core growth, we included 2 cohorts in the study, cohort 1 of 342 patients for derivation and cohort 2 of 414 patients for validation purpose.MethodsAcute ischemic stroke patients with large vessel occlusion were included. Core growth rate was calculated by the following equation: Core growth rate = Acute core volume on CTP/Time from stroke onset to CTP. Collateral status was assessed by the ratio of severe hypoperfusion volume within the hypoperfusion region of CTP. The CTP collateral index was categorized in tertiles; for each tertile, core growth rate was summarized as median and inter-quartile range. Simple linear regressions were then performed to measure the predictive power of CTP collateral index in core growth rate.ResultsFor patients allocated to good collateral on CT perfusion (tertile 1 of collateral index), moderate collateral (tertile 2), and poor collateral (tertile 3), the median core growth rate was 2.93 mL/h (1.10–7.94), 8.65 mL/h (4.53–18.13), and 25.41 mL/h (12.83–45.07) respectively. Increments in the collateral index by 1% resulted in an increase of core growth by 0.57 mL/h (coefficient = 0.57, 95% confidence interval = [0.46, 0.68], p < 0.001). The relationship of core growth and CTP collateral index was validated in cohort 2. An increment in collateral index by 1% resulted in an increase of core growth by 0.59 mL/h (coefficient = 0.59 [0.48–0.71], p < 0.001) in cohort 2.ConclusionCollateral status is a major determinant of ischemic core growth.

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Noncontrast Computed Tomography e-Stroke Infarct Volume Is Similar to RAPID Computed Tomography Perfusion in Estimating Postreperfusion Infarct Volumes

Stroke ◽

10.1161/strokeaha.120.031651 ◽

2021 ◽

Vol 52 (2) ◽

pp. 634-641 ◽

Cited By ~ 1

Author(s):

Mehdi Bouslama ◽

Krishnan Ravindran ◽

George Harston ◽

Gabriel M. Rodrigues ◽

Leonardo Pisani ◽

...

Keyword(s):

Computed Tomography ◽

Odds Ratio ◽

Functional Outcomes ◽

Adjusted Odds Ratio ◽

Infarct Volume ◽

Tertiary Care ◽

Computed Tomography Perfusion ◽

Ischemic Core ◽

Noncontrast Computed Tomography ◽

Core Volume

Background and Purpose: The e-Stroke Suite software (Brainomix, Oxford, United Kingdom) is a tool designed for the automated quantification of The Alberta Stroke Program Early CT Score and ischemic core volumes on noncontrast computed tomography (NCCT). We sought to compare the prediction of postreperfusion infarct volumes and the clinical outcomes across NCCT e-Stroke software versus RAPID (IschemaView, Menlo Park, CA) computed tomography perfusion measurements. Methods: All consecutive patients with anterior circulation large vessel occlusion stroke presenting at a tertiary care center between September 2010 and November 2018 who had available baseline infarct volumes on both NCCT e-Stroke Suite software and RAPID CTP as well as final infarct volume (FIV) measurements and achieved complete reperfusion (modified Thrombolysis in Cerebral Infarction scale 2c-3) post-thrombectomy were included. The associations between estimated baseline ischemic core volumes and FIV as well as 90-day functional outcomes were assessed. Results: Four hundred seventy-nine patients met inclusion criteria. Median age was 64 years (55–75), median e-Stroke and computed tomography perfusion ischemic core volumes were 38.4 (21.8–58) and 5 (0–17.7) mL, respectively, whereas median FIV was 22.2 (9.1–56.2) mL. The correlation between e-Stroke and CTP ischemic core volumes was moderate (R=0.44; P <0.001). Similarly, moderate correlations were observed between e-Stroke software ischemic core and FIV (R=0.52; P <0.001) and CTP core and FIV (R=0.43; P <0.001). Subgroup analysis showed that e-Stroke software and CTP performance was similar in the early and late (>6 hours) treatment windows. Multivariate analysis showed that both e-Stroke software NCCT baseline ischemic core volume (adjusted odds ratio, 0.98 [95% CI, 0.97–0.99]) and RAPID CTP ischemic core volume (adjusted odds ratio, 0.98 [95% CI, 0.97–0.99]) were independently and comparably associated with good outcome (modified Rankin Scale score of 0–2) at 90 days. Conclusions: NCCT e-Stroke Suite software performed similarly to RAPID CTP in assessing postreperfusion FIV and functional outcomes for both early- and late-presenting patients. NCCT e-Stroke volumes seems to represent a viable alternative in centers where access to advanced imaging is limited. Moreover, the future development of fusion maps of NCCT and CTP ischemic core estimates may improve upon the current performance of these tools as applied in isolation.

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Computed tomography-based triage of extensive baseline infarction: ASPECTS and collaterals versus perfusion imaging for outcome prediction

Journal of NeuroInterventional Surgery ◽

10.1136/neurintsurg-2020-016848 ◽

2020 ◽

pp. neurintsurg-2020-016848

Author(s):

Rosalie McDonough ◽

Sarah Elsayed ◽

Tobias Djamsched Faizy ◽

Friederike Austein ◽

Peter B Sporns ◽

...

Keyword(s):

Computed Tomography ◽

Functional Outcome ◽

Operating Characteristic ◽

Primary Outcome ◽

Area Under The Curve ◽

Inclusion Criteria ◽

Radiological Score ◽

Ischemic Core ◽

Core Volume ◽

Selection Of

BackgroundPatients presenting with large baseline infarctions are often excluded from mechanical thrombectomy (MT) due to uncertainty surrounding its effect on outcome. We hypothesized that computed tomography perfusion (CTP)-based selection may be predictive of functional outcome in low Alberta Stroke Program Early CT Score (ASPECTS) patients.MethodsThis was a double-center, retrospective analysis of patients presenting with ASPECTS≤5 who received multimodal admission CT imaging between May 2015 and June 2020. The predicted ischemic core (pCore) was defined as a reduction in cerebral blood flow (rCBF), while mismatch volume was defined using time to maximum (Tmax). The pCore perfusion mismatch ratio (CPMR) was also calculated. These parameters (pCore, mismatch volume, and CPMR), as well as a combined radiological score consisting of ASPECTS and collateral status (ASCO score), were tested in logistic regression and receiver operating characteristic (ROC) analyses. The primary outcome was favorable modified Rankin Scale (mRS) at discharge (≤3).ResultsA total of 113 patients met the inclusion criteria. The median ischemic core volume was 74.1 mL (IQR 43.8–121.8). The ASCO score was associated with favorable outcome at discharge (aOR 3.7, 95% CI 1.8 to 10.7, P=0.002), while no association was observed for the CTP parameters. A model including the ASCO score also had significantly higher area under the curve (AUC) values compared with the CTP-based model (0.88 vs 0.64, P=0.018).ConclusionsThe ASCO score was superior to the CTP-based model for the prediction of good functional outcome and could represent a quick, practical, and easily implemented method for the selection of low ASPECTS patients most likely benefit from MT.

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Abstract TP91: Unfavorable Baseline Hypoperfusion Intensity Ratio is Associated With Infarct Growth and Poor Outcome in Patients With Distal MCA Occlusions

Stroke ◽

10.1161/str.51.suppl_1.tp91 ◽

2020 ◽

Vol 51 (Suppl_1) ◽

Author(s):

Adam MacLellan ◽

Michael Mlynash ◽

Stephanie Kemp ◽

Soren Christensen ◽

Michael Marks ◽

...

Keyword(s):

Functional Outcome ◽

Intensity Ratio ◽

Ct Perfusion ◽

Anterior Circulation ◽

Excellent Functional Outcome ◽

The Mean ◽

Ischemic Core ◽

Core Volume ◽

Distal Middle Cerebral Artery

Background: A low hypoperfusion intensity ratio (HIR) predicts good collateral vessel status and correlates with infarct growth and functional outcome in early window patients with proximal large vessel anterior circulation occlusions. Its performance in predicting clinical and radiologic outcome has not been assessed in patients with more distal occlusions. In this retrospective analysis of the CT Perfusion to Predict Response to Recanalization in Ischemic Stroke (CRISP) study, we hypothesized that a favorable baseline HIR would predict less infarct growth in patients with distal middle cerebral artery (MCA) occlusions. Methodology: Patients with occlusions of an M2 or M3 branch of the MCA on catheter angiography were included; all patients underwent mechanical thrombectomy with TICI2B/3 reperfusion. Baseline ischemic core volume and HIR (Tmax >10s / Tmax >6s) were assessed with RAPID software; late follow-up infarct volumes (>36 hours from initial CT perfusion) were manually determined from DWI MRI. Excellent functional outcome was defined as a modified Rankin score of 0-1. Results: Fourteen patients with baseline perfusion and late follow-up imaging were included; nine patients presented with M2 occlusions, and 5 with M3 occlusions. The mean baseline HIR of 0.48 was used to dichotomize patients into favorable or unfavorable baseline profiles. Patients with a favorable baseline HIR had significantly smaller baseline ischemic core volumes (0 mL [IQR 0-3.3] vs. 14.0 mL [IQR 8.7-22.1], p=0.01), smaller final infarct volumes (16.1 mL [IQR 12.7-41.2] vs. 71.4 mL [IQR 43.8-113.5], p=0.01) and less infarct growth (16.1 mL [IQR 9.4-31.9] vs. 49.0 mL [IQR 31.1-100.8], p=0.03). Excellent functional outcome was achieved in 6/6 (100%) of those with favorable baseline HIR, versus 3/8 (37.5%) with unfavorable baseline profile (p=0.03). Conclusion: In patients with distal MCA occlusions, poor collateral status at baseline as demonstrated by a high HIR score is associated with more infarct growth and worse clinical outcomes. HIR may be helpful for guiding thrombectomy decisions in patients with distal occlusions and warrants further prospective study in this population.

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Abstract P549: Total Small Vessel Disease Burden Not Associated With Functional Independence After Endovascular Treatment in Acute Ischemic Stroke Patients

Stroke ◽

10.1161/str.52.suppl_1.p549 ◽

2021 ◽

Vol 52 (Suppl_1) ◽

Author(s):

Lina Zheng ◽

Xinyi Leng ◽

Ximing Nie ◽

Hongyi Yan ◽

Thomas W Leung ◽

...

Keyword(s):

Endovascular Treatment ◽

Primary Outcome ◽

Small Vessel Disease ◽

Functional Independence ◽

Small Vessel ◽

Perivascular Spaces ◽

Stroke Patients ◽

Vessel Occlusion ◽

Vessel Disease ◽

Secondary Outcomes

Background: Individual small vessel disease (SVD) markers had been associated with outcomes of endovascular treatment (EVT) in acute stroke patients. We aimed to investigate the associations between total SVD burden and outcomes in such patients. Methods: In a nation-wide multicenter registration study, we enrolled stroke patients with anterior circulation large vessel occlusion (LVO) receiving EVT, who had undergone 3T MRI. Presence of lacunes, white matter hyperintensities, cerebral microbleeds and perivascular spaces in both hemispheres were assessed in MRI and each marker was assigned a score of 0 or 1 by presence. A total SVD burden score (0-4) was calculated by summing up the individual scores, which was dichotomized as none-to-mild (score 0-2) and moderate-to-severe (score 3-4). The primary outcome was 90-day functional independence, defined as modified Rankin Scale (mRS) of 0-2. Secondary outcomes included change in NIHSS from baseline to 7 days, early neurological deterioration (END), symptomatic intracranial hemorrhage and 90-day mortality. We investigated the associations of dichotomized total SVD burden score with the outcomes using binary logistic regression analyses. Results: Of the 202 patients (65.38% male; mean age 65.54 ± 11.93 years) enrolled, 176 patients had none-to-mild and 26 had moderate-to-severe total SVD burden. Those with moderate-to-severe SVD were older (mean age 69.8 versus 64.7; P=0.043) and more of them had a prior stroke (42.31% versus 23.3%; P=0.039), compared with otherwise. Dichotomized total SVD burden was not significantly associated with the primary outcome, 90-day functional independence (moderate-to-severe versus none-to-mild SVD burden: 53.85% versus 47.13%; OR 0.76, 95% CI 0.33-1.75; P=0.523). Although moderate-to-severe total SVD burden was associated with a higher rate of END (15.38% versus 3.43%; OR 5.12; 95% CI 1.34-19.58; P=0.017), no significant association was detected between the total SVD burden and other secondary outcomes. Conclusions: The total SVD burden as assessed in MRI was not significantly associated with the chance of obtaining functional independence at 90 days in LVO-stroke patients receiving EVT. A higher total SVD burden may not be an exclusion criteria for clinical decision for EVT.

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Outcomes of endovascular thrombectomy in patients selected by computed tomography perfusion imaging – a matched cohort study comparing nonagenarians to younger patients

Journal of NeuroInterventional Surgery ◽

10.1136/neurintsurg-2021-017727 ◽

2021 ◽

pp. neurintsurg-2021-017727

Author(s):

Rahul Rahangdale ◽

Christopher Todd Hackett ◽

Russell Cerejo ◽

Nicholas M Fuller ◽

Konark Malhotra ◽

...

Keyword(s):

Computed Tomography ◽

Primary Outcome ◽

Functional Independence ◽

Matched Cohort ◽

Limited Information ◽

Anterior Circulation ◽

Endovascular Thrombectomy ◽

Younger Patients ◽

Computed Tomography Perfusion ◽

Symptomatic Intracranial Hemorrhage

BackgroundEndovascular thrombectomy (EVT) is efficacious for appropriately selected patients with large vessel occlusions (LVO) up to 24 hours from symptom onset. There is limited information on outcomes of nonagenarians, selected with computed tomography perfusion (CTP) imaging.MethodsWe retrospectively analyzed data from a large academic hospital between December 2017 and October 2019. Patients receiving EVT for anterior circulation LVO were stratified into nonagenarian (≥90 years) and younger (<90 years) groups. We performed propensity score matching on 18 covariates. In the matched cohort we compared: primary outcome of inpatient mortality and secondary outcomes of successful reperfusion (TICI ≥2B), symptomatic intracranial hemorrhage (sICH), and functional independence. Subgroup analysis compared CTP predicted core volumes in nonagenarians with outcomes.ResultsOverall, 214 consecutive patients (26 nonagenarians, 188 younger) underwent EVT. Nonagenarians were aged 92.8±2.9 years and younger patients were 74.5±13.5 years. Mortality rate was significantly greater in nonagenarians compared with younger patients (43.5% vs 10.4%, OR 9.33, 95% CI 2.88 to 47.97, P<0.0001) and a greater proportion of nonagenarians developed sICH (13.0% vs 3.0%, OR 6.00, 95% CI 1.34 to 55.20, P=0.02). There were no significant differences for successful reperfusion (P=1.00) or functional independence (P=0.75). Nonagenarians selected with smaller ischemic core volumes had decreased mortality rates (P=0.045).ConclusionsNonagenarians were noted to have greater mortality and sICH rates following EVT compared with matched younger patients, which may be ameliorated by selecting patients with smaller CTP core volumes. Nonagenarians undergoing EVT had similar rates of successful reperfusion and functional independence compared with the younger cohort.

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