Infarct Core Research Articles

Abstract 155: Critical Care Decisions After Large Core Cerebral Infarctions: A Secondary Analysis From the SELECT2 Trial

Background/hypothesis: The SELECT2 trial randomly assigned patients with LVO and large ischemic cores to either endovascular thrombectomy (EVT) or medical management (MM). This population is at high risk for cerebral edema and other complications, often leading to critical decisions about decompressive hemicraniectomy (DHC) or early withdrawal of care (WOC). We hypothesized that patients initially treated with EVT were more likely to get life-sustaining care regardless of recanalization success, presumably because initial treatment with EVT led toward an expectation of aggressive care, while those treated with MM expected futility. Methods: We analyzed the full SELECT2 study population using the as-treated principle, comparing the use of DHC and early (within 7 days from randomization) transition to comfort measures/WOC. We also compared these decisions based on recanalization success in those receiving EVT. We further tested baseline characteristics for association with these outcomes. Results: Patients treated with EVT were as likely to undergo DHC (aRR:1.19 [0.75-1.88], p=0.46) or WOC (aRR:0.94 [0.66-1.34], p=0.72) as those given MM (Table). Time to DHC was also similar (EVT 47[19-74] vs. MM 36[27-61] hours, p=0.95). Patients with successful (mTICI≥2b) recanalization were numerically less likely to undergo DHC than those with unsuccessful (TICI 0-2a) recanalization (aRR:0.66 [0.33-1.3], p=0.23), while WOC was similar (Table). Larger estimated core volumes were associated with both DHC and WOC, with DHC used more in younger and WOC more in older patients. Conclusions: In the SELECT2 trial of patients with large infarct cores, DHC was performed in ~1 in 6 and WOC in ~1 in 5, without an observed difference based on treatment with EVT or MM. The similar distribution of decisions to proceed with DHC or to change goals of care to acute palliative measures provides reassurance that the overall trial outcomes were not biased by open-label treatment allocation.

Abstract 152: Endovascular Therapy versus Medical Management for Acute Ischemic Stroke With Large Infarct: A Time-Benefit Relationship Analysis

Objective: Recent randomized trials demonstrated the benefit of endovascular thrombectomy for acute ischemic stroke with large infarct. We aimed to characterize the effect of time to treatment on the benefit of endovascular therapy compared to medical management among patients with acute large ischemic stroke. Methods: Analysis the Endovascular Therapy in Acute Anterior Circulation Large Vessel Occlusive Patients with a Large Infarct Core trial (ANGEL-ASPECT), which was a multicenter, randomized trial at 46 comprehensive stroke centers in China from August 2020 to October 2022. Onset to arterial puncture time (OPT) associated with outcomes of endovascular therapy were analyzed as a category and continuous variable. The primary outcome was favorable outcome (modified Rankin scale 0-3) at 90 days. Secondary outcomes included degree of disability (modified Rankin scale range), symptomatic intracranial hemorrhage, any intracranial hemorrhage, and mortality. Results: Among 455 eligible patients, the median age was 68 years, and median Alberta Stroke Program Early Computed Tomography Score was 3 (interquartile range 3-4). Compared with medical management alone, endovascular therapy plus medical management was associated with higher rates of favorable outcome with OPT within 6 hours (44.4% vs 29.9%, adjusted odds ratio[aOR] 2.78 [95% confidence interval [CI] 1.22-6.32]), 6-12 hours (45.7% vs 29.6%, aOR 2.39 [95% CI 1.21-4.71]), but not in OPT beyond 12 hours (51.6% vs 41.4%, aOR 2.05 [95% CI, 0.88-4.77]). The benefit in favorable outcome became nonsignificant after OPT of 13 hours and 22 minutes. In three OPT intervals, the odds of better disability outcome with endovascular therapy plus medical management than medical management alone were observed; the rates of symptomatic intracranial hemorrhage and mortality were similar, though the rates of any intracranial hemorrhage increased. Conclusion: In patients with large cerebral infarction, endovascular therapy plus medical management was efficacious in improving functional outcomes with acceptable safety in a broad time window of 0 to 24 hours, but greater benefit was observed with earlier treatment. A pooled analysis with larger sample size is needed.

Abstract WP117: Improvement of Collateral Status in Thrombectomy-Eligible Stroke Patients During Inter-Hospital Transfer: Association With Clinical Factors and Outcome

Background: Ischemic stroke patients who are eligible for endovascular therapy (EVT), can be transferred from a primary stroke center (PSC) to an EVT-capable comprehensive stroke center (CSC). Little is known about the dynamics of the collateral circulation in this time-window. We aimed to explore changes in collateral status during inter-hospital transfer among patients with poor collaterals on presentation to the PSC. Methods: Data from patients with an anterior circulation large vessel occlusion (LVO), transferred to two CSCs were prospectively collected. A CT perfusion was obtained at the PSC followed by an MRI immediately on arrival at the CSC. The hypoperfusion intensity ratio (HIR), a measure of collateral blood flow, was calculated as the ratio of the Tmax volumes of >10s and >6s. Only patients with stable LVO at the CSC and poor collateral status at the PSC (HIR ≥ 0.40) were included. An HIR < 0.40 in the CSC and a difference ≥ 0.10 was considered as HIR improvement. Results: Data from 104 patients with perfusion imaging at both PSC and CSC, were analyzed. Of them, we included 59 patients with an HIR ≥ 0.40 at the PSC. Sixteen (27%) patients experienced HIR improvement during transfer (Figure 1) . A smaller baseline core volume was independently associated with HIR improvement (OR for every 10 ml increase = 0.46 {95%CI 0.21-0.81}; p=0.03). Collateral improvement was associated with slower infarct growth during transfer (2.45 {95%CI 1.03-3.62} vs 7.77 {95%CI 4.56-17.86} ml/h; p<0.01) and a better functional outcome at 90 days post stroke (median mRS 3 {IQR 1-5} vs 4 {IQR 4-6}; p=0.01). Conclusion: During inter-hospital transfer spontaneous improvement in collateral status, as measured by HIR, is commonly seen, and associated with a smaller infarct core at the PSC, slower infarct growth during transfer, and better functional outcomes. Future neuroprotective trials targeted at collateral improvement, might consider the use of the HIR change as a surrogate outcome marker.

Abstract TP133: Clot Burden Score Correlates Best With Hypoperfusion Volume and Predicts Final Infarct ASPECTS<=3 in Anterior Circulation Ischemic Strokes

Purpose: Clot Burden Score (CBS) is a semiquantitative measure of thrombus extent on CTA for proximal anterior circulation strokes whose relationship with perfusion metrics has not been fully explored. CBS has potential added value during stroke triage if perfusion imaging is not available or suboptimal. We aimed to investigate if CBS is (1) correlated to perfusion estimates of infarct core volume, hypoperfusion volume, or collateral status, and (2) a predictor of final infarct extent without reperfusion therapy. Methods: Retrospective analysis included consecutive patients (1) arriving <24 hours from onset, (2) with occlusion in the intracranial ICA, M1, M2, or A1 or combination, (3) with concurrent CTP, and (4) had followup CT or DWI during hospitalization. CBS is a 10-point negative ordinal scale: 2-points subtracted for occlusion of supraclinoid ICA, proximal M1, or distal M1, and 1-point subtracted for occlusion of infraclinoid ICA, A1, or M2. Correlation of CBS with perfusion metrics was evaluated using Spearman's rank test. Final infarct ASPECTS were scored for those without thrombolysis or thrombectomy. Multivariate logistic regression was used to identify predictors of final ASPECTS<=3 (approximating >=100mL). ROC analysis was evaluated to assess performance and optimal thresholds. Results: 222 patients included with median (IQR) age of 75 (65-84) and NIHSS of 18 (11-24). Median CBS was 7 (6-9) and best correlated to Tmax>6s r=-0.579 (hypoperfusion volume), followed by HIR r=-0.401 (collateral status) and rCBF<30% r=-0.306 (core volume), all p<0.001. 71 (32.0%) untreated patients also had median CBS of 7 (6-9). CBS and Tmax>6s had the strongest correlation to final ASPECTS in this subgroup, r=0.637 and r=-0.686 (both p<0.001). 22 of these (30.1%) had final ASPECTS<=3. Multivariate logistic regression including CBS, Tmax>6s, HIR, baseline ASPECTS, and NIHSS showed only CBS as independent predictor of final ASPECTS<=3 (p<0.001). ROC AUC for CBS was 0.902 [95% CI: 0.819-0.985] with optimal threshold of <=6 for sensitivity 86.4% and specificity 81.6%. Conclusion: CBS as a measure of thrombus extent correlates best with baseline hypoperfusion volume on CTP and independently predicts very large final infarcts (ASPECTS<=3) without treatment.

Random expert sampling for deep learning segmentation of acute ischemic stroke on non-contrast CT.

Outlining acutely infarcted tissue on non-contrast CT is a challenging task for which human inter-reader agreement is limited. We explored two different methods for training a supervised deep learning algorithm: one that used a segmentation defined by majority vote among experts and another that trained randomly on separate individual expert segmentations. The data set consisted of 260 non-contrast CT studies in 233 patients with acute ischemic stroke recruited from the multicenter DEFUSE 3 (Endovascular Therapy Following Imaging Evaluation for Ischemic Stroke 3) trial. Additional external validation was performed using 33 patients with matched stroke onset times from the University Hospital Lausanne. A benchmark U-Net was trained on the reference annotations of three experienced neuroradiologists to segment ischemic brain tissue using majority vote and random expert sampling training schemes. The median of volume, overlap, and distance segmentation metrics were determined for agreement in lesion segmentations between (1) three experts, (2) the majority model and each expert, and (3) the random model and each expert. The two sided Wilcoxon signed rank test was used to compare performances (1) to 2) and (1) to (3). We further compared volumes with the 24 hour follow-up diffusion weighted imaging (DWI, final infarct core) and correlations with clinical outcome (modified Rankin Scale (mRS) at 90 days) with the Spearman method. The random model outperformed the inter-expert agreement ((1) to (2)) and the majority model ((1) to (3)) (dice 0.51±0.04 vs 0.36±0.05 (P<0.0001) vs 0.45±0.05 (P<0.0001)). The random model predicted volume correlated with clinical outcome (0.19, P<0.05), whereas the median expert volume and majority model volume did not. There was no significant difference when comparing the volume correlations between random model, median expert volume, and majority model to 24 hour follow-up DWI volume (P>0.05, n=51). The random model for ischemic injury delineation on non-contrast CT surpassed the inter-expert agreement ((1) to (2)) and the performance of the majority model ((1) to (3)). We showed that the random model volumetric measures of the model were consistent with 24 hour follow-up DWI.

Abstract WP190: Comparison of Collateral Score to ASPECTS to Exclude "Very Large" Infarct Core Volumes in Anterior Circulation Large Vessel Occlusion Strokes at 0-24 Hours

Purpose: ASPECTS&lt;3 was an explicit exclusion criterion in the SELECT2 trial to exclude "very large" infarcts (&gt;100mL) for reperfusion using endovascular thrombectomy (EVT). While specific, ASPECTS&lt;3 may be too insensitive of a threshold on noncontrast CT at 0-24 hours (especially 0-6 hours). We aim to determine if CTA based Collateral Score (CS) can be a more sensitive surrogate marker for infarct core volume (ICV)&gt;100mL while maintaining similar specificity to ASPECTS. Methods: Retrospective analysis included consecutive stroke patients arriving within 24 hours of onset, with intracranial ICA and/or M1 occlusion on CTA, and had concurrent CT perfusion. RAPID AI software estimated ICV using the rCBF&lt;30% threshold. CS was scored on CTA using the method of Tan et al on a 4-point scale for % collaterals compared to contralateral side: 0 none, 1 &gt;0 but &lt;50%, 2 &gt;=50 but &lt;100%, and 3 100%. ROC curve analysis was used to find the optimal CS cutpoint with high specificity for ICV&gt;100mL. Sensitivity and specificity of that CS threshold vs ASPECTS&lt;3 were compared using the N-1 chi square test. Results: 164 patients were included with median (IQR) age of 74 (66-84), NIHSS of 20 (12-25), and time of onset-to-CT of 4 hours (2-7.5). The LVOs were 17 ICA (10.4%), 108 M1 (65.9%), and 39 both (23.8%), with median ICV of 12mL (0-45). 16 patients had ICV&gt;100mL (9.8%) with median of 136mL (105-172). Using ASPECTS&lt;3 identified only 1 of these (ICV of 118mL at 18.5 hours), sensitivity of 6.3% (95% CI: 0.16-30.2%), with no false positives, specificity of 100% (95% CI: 97.6-100%). ROC analysis for CS showed AUC=0.818 (p&lt;0.001), with maximal specificity at CS=0 (no visible collaterals). Using CS=0 identified 6 of these infarcts, sensitivity of 37.5% [95% CI: 15.2-64.6%], with 2 false positives, specificity of 98.7% [95% CI: 95.2-99.8%]. The 2 false positives were ICV of 97mL at 2 hours and 96mL at 3 hours. The improved sensitivity of CS=0 over ASPECTS&lt;3 was significant (p=0.036) while the difference in specificity was not (p=0.144). Conclusion: In our cohort of LVOs, CS=0 was a more sensitive surrogate marker for ICV&gt;100mL compared to ASPECTS&lt;3 while maintaining near 100% specificity. If confirmed in future prospective studies, CS=0 has the potential to further streamline patient selection for EVT.

Abstract WMP62: Infarct Core Volume Estimation on Non-Contrast Computed Tomography in Late Window Patients Using a Machine Learning Algorithm Software

Introduction: A simplified patient selection paradigm can reduce time to reperfusion and widen the eligibility of large vessel occlusions (LVO) for endovascular therapy (EVT). We developed and externally validated a machine learning (ML) algorithm to estimate infarct core volume (ICV) on non-contrast computed tomography (NCCT) in anterior circulation LVOs presenting in the late window (≥ 6-24 hours). Methods: LVOs from prospective databases in US and Spain were included. For development, 2858 stroke activations with NCCT/CT angiography[s1] were included. For validation, consecutive LVOs with admission NCCT/CT perfusion (CTP), post-EVT diffusion-weighted imaging (DWI) within 24 hours, and mTICI ≥2b were included. Neuroimaging experts adjudicated ASPECTS on NCCT and final infarct volume (FIV) on DWI (ground truth). ML algorithm was trained using UNet architecture with ResNet 34 encoder to identify ICV on NCCT. Estimated ICVs (algorithm, CTP [&lt;30% cerebral blood flow], and ASPECTS) were compared to ground truth using correlations (intraclass correlation coefficient [ICC] and Spearman’s [r s ]) and Bland Altman plots. Superiority tests between correlations (to compare modalities) and subgroup analyses were performed. Results: 98 patients (median age, 70 years; IQR:59-80; 51% females) were included for validation. Median time to first imaging was 11.4 hours (IQR:9.0-14.7). Correlations (Table) were moderate with the ML algorithm (ICC:0.59) and poor with ASPECTS (r s :-0.31) and CTP ICV (ICC:0.42;). Bland Altman plots showed that ML algorithm had a mean difference closest to zero (-34.2 mL) while the CTP ICV had a larger mean difference (-45.8 mL). Superiority tests (Table), [s2] ML algorithm correlation showed superiority to both the CTP ( p sup =.018) and ASPECTS ( p sup =.003) correlations. Conclusion: On late window patients, estimation of ICV on NCCT with the ML algorithm seems to be superior to CTP and ASPECTS. Further prospective studies are needed.

Abstract WP125: The Presence of a Ghost Infarct Core is Associated With Fast Core Growth in Acute Ischemic Stroke

Introduction: The overestimation of ischemic core volume by computed tomography perfusion (CTP) is a critical concern in the selection of candidates for reperfusion therapy. This phenomenon is termed a ghost infarct core (GIC). Core growth rate has emerged as an indicator of ischemic severity. The aim of the present study was to elucidate the association between the presence of a GIC and the core growth rate. Methods: Consecutive patients with acute ischemic stroke due to large vessel occlusion who underwent mechanical thrombectomy in our institute from March 2017 to July 2022 were enrolled. The initial ischemic core was measured by pretreatment CTP, and the final infarct volume (FIV) was measured by diffusion-weighted imaging. A GIC was defined by initial ischemic core volume minus FIV &gt;10 mL. The core growth rate was calculated by dividing the initial ischemic core volume by time from stroke onset to CTP acquisition. Univariable analysis and a multivariable logistic regression model were used to evaluate the association between GIC-positive and the core growth rate; complete recanalization, onset to imaging time, and imaging to recanalization time were included as covariates. Results: Ninety-one patients were included in the study. Of these, 21 patients (23.1%) were GIC-positive. The GIC-positive group had higher core growth rate (14.2 [2.6-46.7] vs 4.8 [1.6-17.1] mL/h, p=0.021) and complete recanalization (n=15 (71.4%) vs 29 (41.4%), p=0.016) compared to the GIC-negative group. On receiver operating characteristic curve analysis, the optimal cutoff point of the core growth rate to predict GIC-positive was 22 mL/h (sensitivity, 0.48; specificity, 0.85; area under the curve, 0.67). Multivariable logistic regression analysis showed that core growth rate ≥22 mL/h (OR 6.44, 95% CI [1.59-26.10], p=0.006) and complete recanalization (OR 3.72, 95% CI [1.14-12.08], p=0.022) were independent predictors of GIC-positive. Conclusions: A GIC was associated with fast core growth in acute ischemic stroke. Overestimation of the initial ischemic core may be determined by core growth speed, not a clock time.

Abstract TP130: Prevalence of Fast Progressors of Infarct Growth in Anterior Circulation Large Vessel Occlusions &lt;6 Hours From Onset

Background/Purpose: Fast progressors (FP) of infarct growth in anterior circulation large vessel occlusions (LVO) may be prevalent in the &lt;6h period depending on how it is defined. The 3 recently completed randomized trials of endovascular thrombectomy (EVT) on large infarct core volumes (ICV) all used ASPECTS criterion of 3-5 which approximates 70-100mL in absolute volume. We aimed to investigate the prevalence of FP in LVO &lt;6h and how many of these were at or on pace to reach the 70mL or 100mL ICV threshold for EVT selection. Methods: We retrospectively included consecutive stroke patients arriving &lt;6h from symptom onset with ICA and/or M1 occlusion on CTA and had concurrent CT perfusion (CTP). RAPID AI software generated maps of ICV depicted as rCBF&lt;30% and critical hypoperfusion depicted as Tmax&gt;6s. Infarct growth rate (IGR) was calculated as ICV/onset-to-imaging time. FP was defined at 2 levels: as "FP70" with IGR &gt;11.7mL/h (which would result in an ICV &gt;70mL by 6h) and had &gt;=70mL of overall hypoperfusion present; and as "FP100" with IGR &gt;16.7mL/h (which would result in an ICV &gt;100mL by 6h) and had &gt;=100mL of overall hypoperfusion present. Results: 108 patients were included with median (IQR) age of 75.5 (67-85), NIHSS of 20 (12-24), onset time of 2h (1.5-4), median ICV of 11mL (0-40), hypoperfusion volume of 122mL (70-164), and mismatch volume of 86.5mL (58-130). The sites of LVO were ICA 12 (11.1%), M1 73 (67.6%), and both 23 (21.3%). Median IGR for the cohort was 3.8mL/h (0-16.4). 31 FP70 were found (28.7%, 95% CI: 19.5-40.7%) with median IGR of 31.3mL/h (16.8-42). 14 of these (45.2%, 95% CI: 24.7-75.8%) already had ICV&gt;70mL upon arrival, with median of 100mL (86-156) and 8 of 14 also showed mismatch ratio &lt;1.8. 25 FP100 were found (23.1%, 95% CI: 16.2-36.9%) with median IGR of 38.7mL/h (24.6-51.4). 8 of these (32.0%, 95% CI: 13.8-63.1%) already had ICV&gt;100mL upon arrival, with median of 138mL (101-172) and 5 of 8 also showed mismatch ratio &lt;1.8. Conclusion: In a cohort of acute anterior circulation LVO strokes &lt;6h from onset, the vast majority were good candidates for EVT with small to medium size core volumes. However, ~25% were fast progressors that may require more caution in selection, with ICV at or on pace to reach 70-100mL thresholds by 6h.

Abstract 40: Relationship of Collateral Status With Clinical Outcomes in Endovascular Thrombectomy for Large Core Stroke: A SELECT2 Subanalysis

Background: Previous studies demonstrating association of collateral status with clinical outcomes after endovascular thrombectomy (EVT) excluded patients with large core infarcts. We analyzed the association of collateral status with clinical outcomes and EVT treatment effect in SELECT2. Methods: In SELECT2, a central core lab adjudicated CT-angiographic collateral status using collateral scores (CS) by Tan et al. Patients were stratified based on CS into poor (CS 0-1) vs good (CS 2-3) collaterals. The primary outcome was the distribution of modified Rankin Scale score at 90-day follow-up. Models were adjusted for core volume, ASPECTS in addition to age, stroke severity and time to randomization. Results: Of 352 patients, 180 received EVT. Median collateral status was 2(IQR 1-2). Patients presenting &lt;6h after last known well (LKW) (n=100) had poorer collaterals than those presenting at 6-24 hours (n=252), median 1 (1-2) vs 2 (1-2), p&lt;0.001. Collateral status inversely correlated with CTP core volume (Rho=-0.32, p&lt;0.0001), but not with CT ASPECTS (Rho=0.07, p=0.16). Overall, point estimates favored EVT in patients with poor (CS 0-1) [aGenOR: 1.32, 95% CI: 0.98-1.79, p=0.068] and good (CS 2-3) collaterals [aGenOR: 1.97, 95% CI: 1.43-2.72, p&lt;0.001] without significant heterogeneity [p-interaction=0.094]. However, in the earlier 0-6h time window, there was evidence of treatment effect hetermogeneity with a larger treatment effect when good collaterals were present [aGenOR: 4.10, 95% CI: 1.81-9.29] and an absent treatment effect when only poor collaterals were observed [aGenOR: 1.26, 95% CI: 0.79-1.99], p-interaction=0.023. In the late time window, (6-12h), the EVT treatment effect did not differ significantly between poor collaterals (aGenOR: 1.35, 95% CI: 0.91-2.01) and good collaterals (aGenOR: 1.78, 95% CI: 1.24-2.56, p-interaction=0.50). Conclusion: Collateral status was worse in large core patients presenting in early (&lt;6 hours) window; and correlated with ischemic core volume but not ASPECTS. Collaterals status modified EVT treatment effect in the early but not the late time window, in which both good and poor collaterals still benefited from EVT. Clinicaltrials.gov registration: NCT03876457

Abstract TP131: Computed Tomography Perfusion Imaging Patterns Are Similar Before and After Interfacility Transfer of Ischemic Stroke Patients

Background: Large vessel occlusion (LVO) stroke patients are often transferred from regional hospitals to comprehensive stroke centers (CSC) for thrombectomy. The need for repeat imaging at CSCs prior to intervention is unclear. We compared regional hospital and CSC perfusion imaging results for interfacility transfers in a single health system. Methods: We analyzed a cohort of patients in western Michigan who received CT perfusion imaging before and after transfer to a CSC. Perfusion mismatch (MM), core infarct volume (CIV), and favorability of imaging for mechanical thrombectomy (MT) candidacy were compared between the regional and CSC studies. A favorable imaging profile was defined as the presence of LVO, MM volume &gt;10 mL, and MM/CIV ratio of &gt;1.2. Linear regression was used to examine predictors of infarct growth during transfer. Results: Over a 10-month period, 25 patients met inclusion criteria. The median age was 76 (IQR 66-81), 60% were male, median NIHSS was 11 (IQR 2-18), and most patients had occlusion of the internal carotid or middle cerebral arteries (72%). The median time from last known well to initial CT was 250 minutes (IQR 85-620). Regional median MM volume was 52 mL (IQR 8-97), CIV was 0 mL (IQR 0-13), and hypoperfusion intensity ratio (HIR) was 0.25 (IQR 0-0.34). The median time between CTs was 152 minutes (IQR 139-226). The median change in MM volume was -3 mL (IQR -27-3) and median CIV growth rate was 0 mL/hr (IQR 0-2.0). In a multivariable regression model, higher HIR (β=23.2, p=0.012) and minutes between imaging studies (β=0.10, p=0.021) were associated with CIV growth. Sixteen patients (64%) had favorable imaging profiles for MT at the regional hospital. Of these, 15 (93.8%) continued to have a favorable CSC imaging profiles and 9 (56.2%) underwent MT. Of the 9 patients without favorable regional imaging profiles, 1 (11.1%) had a favorable CSC imaging profile and 2 (22.2%) underwent MT. Conclusion: In our sample, regional and CSC perfusion imaging patterns were similar and patients infrequently crossed thresholds for MT candidacy between studies. Initial HIR and longer delays between were independently associated with infarct growth during transfers, however overall infarct growth was very small.

Abstract 157: Endovascular Treatment of Acute Ischemic Stroke Patients With Tandem Lesions Presenting With Low Alberta Stroke Program Early Computed Tomography Score

Background and objective: The effect of endovascular therapy (EVT) in tandem lesion (TL) patients with baseline large core infarct is unclear. We investigated the safety and efficacy of EVT in TL patients with low ASPECTS (0-5). We also compared the safety of acute carotid stenting (CAS) in TLs with low ASPECTS. Methods: This prospective multicenter study from 16 centers included patients with anterior circulation TL from 2015-2020. Inclusion criteria were age ≥18 years, EVT for intracranial occlusion, and underwent treatment for extracranial ICA lesions with &gt;70% stenosis. Patients were divided into ASPECTS 0-5 and 6-10 groups. Inverse Probability of Treatment Weighting (IPTW) was used to assess the association of outcomes. Results: Of the 691 patients, 44 had an ASPECTS 0-5 and 505 had ASPECTS 6-10. After matching, there were decreased odds of favorable shift in mRS at 90 days (30.7% vs 48%, OR: 0.52, CI:0.29-0.97; p=0.002), higher rates of sICH (11.4% vs 3.6%, OR: 3.18, CI: 1.07-9.49; p=0.038), 90-day mortality (35.9% vs 16.3%; OR: 2.35, CI: 1.16-4.74; p=0.017) and comparable rates of successful reperfusion (79.5% vs 88.7%; OR: 0.73, CI: 0.33-1.63, p=0.45), excellent reperfusion (50% vs 49.1%; OR: 1.35, CI: 0.72-2.53; p=0.35) excellent reperfusion (50% vs 49.1%; OR: 1.35, CI: 0.72-2.53; p=0.35) in the ASPECTS 0-5 compared with 6-10. Among patients with ASPECTS 0-5, no significant differences were noted for sICH (OR: 0.31, CI: 0.03-3.05; p=0.32), PH2 (OR: 1.14, CI: 0.26-5.02; p=0.86), petechial hemorrhages (OR: 0.79, CI: 0.10-6.05; p=0.82), and 90-day mortality (OR: 0.68, CI: 0.14-3.45; p=0.6) in patients with stenting (18/44) versus no-stenting (25/44). Conclusion: This multicenter cohort study of AIS patients with TLs demonstrated poor outcomes for functional independence at 90 days and higher rates of sICH and mortality in patients with low ASPECTS (0-5). Among patients with ASPECTS 0-5, rates of sICH and mortality were similar in stenting and non-stenting groups.

Relationship between blood glucose variation, collateral circulation and Batman score and prognosis after mechanical thrombectomy with Solitaire stent in acute posterior vascular occlusive stroke

Objective: To explore the relationship between blood glucose variability, collateral circulation and basilar artery computed scan angiography score (Batman) and prognosis of mechanical thrombectomy with Solitaire stent in patients with large vascular occlusive APCI. Methods: A retrospective study was conducted on 113 patients with large vessel occlusive APCI who underwent Solitaire stent mechanical thrombectomy in the Department of Neurology of Nanyang Central Hospital from March 2021 to July 2022. According to the prognosis, they were divided into outcome group (46 cases) and adverse group (67 cases). Evaluate the prognosis based on the Modified Rankin Scale three months after the surgery. The differences in collateral circulation, GV and Batman score between the two groups were compared, and the related factors affecting the prognosis of large vessel occlusive APCI patients treated with Solitaire stent mechanical thrombectomy were analyzed by multivariate logistic regression model. Results: The age of 113 patients with acute large vessel occlusive APCI was (65.3±8.9) years old. The proportion of female was 34.5% (39 cases). Compared with the outcome group, the adverse group had a lower proportion of collateral circulation [40 cases (87.0%) vs 47 cases (70.2%)], higher GV score [(25.19±3.54) vs (30.36±4.11) points], lower Batman score [(7.49±1.52) vs (6.65±1.33) points], higher proportion of atrial fibrillation history [16 cases (23.9%) vs 4 cases (8.7%)], higher National Institutes of Health Stroke Scale (NIHSS) score at admission [(8.33±0.74) vs (7.25±0.92) points], larger core infarct volume [(32.57±4.87) vs (29.54±5.14) ml], and longer time from admission to vascular recanalization [(123.52±31.17) vs (102.47±29.54) min] (all P<0.05). Atrial fibrillation history, core infarct volume, NIHSS score at admission, time from admission to vascular recanalization, glycemic variability, collateral circulation, and Batman score were related factors for the prognosis of large vessel occlusive APCI patients treated with Solitaire stent mechanical thrombectomy, with ORvalues (95%CI) of 1.383 (1.124-1.641), 1.166 (1.007-1.350), 4.777 (1.856-12.297), 3.068 (2.379-3.757), 1.477 (1.209-1.806), 0.742 (0.654-0.831), and 0.717 (0.214-1.221), respectively (all P<0.05). Conclusion: Blood glucose variation is a risk factor for prognosis of mechanical thrombectomy with Solitaire stent in patients with large vascular occlusive APCI, and collateral circulation and Batman score are protective factors.

Prevalence of "Ghost Infarct Core" after Endovascular Thrombectomy.

Baseline CTP sometimes overestimates the size of the infarct core ("ghost core" phenomenon). We investigated how often CTP overestimates infarct core compared with 24-hour imaging, and aimed to characterize the patient subgroup in whom a ghost core is most likely to occur. Data are from the randomized controlled ESCAPE-NA1 trial, in which patients with acute ischemic stroke undergoing endovascular treatment were randomized to intravenous nerinetide or placebo. Patients with available baseline CTP and 24-hour follow-up imaging were included in the analysis. Ghost infarct core was defined as CTP core volume minus 24-hour infarct volume > 10 mL). Clinical characteristics of patients with versus without ghost core were compared. Associations of ghost core and clinical characteristics were assessed by using multivariable logistic regression. A total of 421 of 1105 patients (38.1%) were included in the analysis. Forty-seven (11.2%) had a ghost core > 10 mL, with a median ghost infarct volume of 13.4 mL (interquartile range 7.6-26.8). Young patient age, complete recanalization, short last known well to CT times, and possibly male sex were associated with ghost infarct core. CTP ghost core occurred in ∼1 of 10 patients, indicating that CTP frequently overestimates the infarct core size at baseline, particularly in young patients with complete recanalization and short ischemia duration.

Overestimation of ischemic core on baseline MRI in acute stroke.

In patients with acute ischemic stroke (AIS), overestimation of ischemic core on MRI-DWI has been described primarily in regions with milder reduced diffusion. We aimed to assess the possibility of ischemic core overestimation on pretreatment MRI despite using more restricted reduced diffusion (apparent diffusion coefficient (ADC) ≤620 × 10-6 mm2/s) in AIS patients with successful reperfusion. In this retrospective single institutional study, AIS patients who had pretreatment MRI underwent successful reperfusion and had follow-up MRI to determine the final infarct volume were reviewed. Pretreatment ischemic core and final infarction volumes were calculated. Ghost core was defined as overestimation of final infarct volume by baseline MRI of >10 mL. Baseline clinical, demographic, and treatment-related factors in this cohort were reviewed. A total of 6/156 (3.8%) patients had overestimated ischemic core volume on baseline MRI, with mean overestimation of 65.6 mL. Three out of six patients had pretreatment ischemic core estimation of >70 mL, while the final infarct volume was <70 mL. All six patients had last known well-to-imaging <120 min, median (IQR): 65 (53-81) minutes. Overestimation of ischemic core, known as ghost core, is rare using severe ADC threshold (≤620 × 10-6 mm2/s), but it does occur in nearly 1 of every 25 patients, confined to hyperacute patients imaged within 120 min of symptom onset. Awareness of this phenomenon carries implications for treatment and trial enrollment.

Effect of computed tomography vs. computed tomography perfusion on mechanical thrombectomy outcomes within 6hours.

It is unclear which selection strategy, plain CT vs. CT perfusion (CTP), is more powerful in predicting outcome after mechanical thrombectomy (MT). We aimed to compare the effect of plain CT and CTP in predicting outcome after MT within 6h. We conducted a prospective analysis of a retrospective cohort from our single-center study, which had occlusion of the internal carotid artery and middle cerebral artery up to the proximal M2 segment and received MT within 6h. According to the Alberta Stroke Program Early CT Score (ASPECTS), patients were divided into a high-ASPECTS group (≥ 6) and a low ASPECTS group (< 6). Similarly, patients were divided into mismatch and no-mismatch groups according to the DEFUSE3 criteria for CTP. A good outcome was defined as a 90-day modified Rankin Scale (mRS) score of ≤ 3. Univariate and binary logistic regression analyses were used to investigate the association between different imaging modality and 90-day mRS score, and mortalities, respectively. The high ASPECTS group included 307 patients (89.2%). The mismatch group included 189 (54.9%) patients meeting the DEFUSE3 criterion. Compared to the low ASPECTS group, the high ASPECTS group had a good outcome (odds ratio (OR), 2.285; [95% confidence interval (CI) (1.106, 4.723)], p = 0.026) and lower mortality (OR, 0.350; [95% CI (0.163, 0.752)], p = 0.007). However, there were no significant differences in good outcomes and mortality between the mismatch and no-mismatch groups. Compared with plain CT, CTP does not provide additional benefits in the selection of patients suitable for MT within 6h. CT perfusion is not superior to plain CT for the prediction of clinical outcomes when selecting patients for mechanical thrombectomy in the first 6h. In that clinical setting, plain CT may be safe in the absence of perfusion data. •The advantage of CT perfusion (CTP) over CT in pre-mechanical thrombectomy (MT) screening has not been proven for patients witha large infarct core. •CTP is not better than plain CT in predicting good outcome following MT within 6h. •Plain CT is sufficient for selecting patients suitable for MT within 6h of large artery occlusion.

Association of dysglycaemia with persistent infarct core iron in patients with acute ST-segment elevation myocardial infarction

BackgroundDysglycaemia increases the risk of myocardial infarction and subsequent recurrent cardiovascular events. However, the role of dysglycaemia in ischemia/reperfusion injury with development of irreversible myocardial tissue alterations remains poorly understood.In this study we aimed to investigate the association of ongoing dysglycaemia with persistence of infarct core iron and their longitudinal changes over time in patients undergoing primary percutaneous coronary intervention (PCI) for acute ST-segment elevation myocardial infarction (STEMI). MethodsWe analyzed 348 STEMI patients treated with primary PCI between 2016 and 2021 that were included in the prospective MARINA-STEMI study (NCT04113356). Peripheral venous blood samples for glucose and glycated hemoglobin (HbA1c) measurements were drawn on admission and 4 months after STEMI. Cardiac magnetic resonance (CMR) imaging including T2 * mapping for infarct core iron assessment was performed at both time points. Associations of dysglycaemia with persistent infarct core iron and iron resolution at 4 months were calculated using multivariable regression analysis. ResultsIntramyocardial hemorrhage was observed in 147 (42%) patients at baseline. Of these, 89 (61%) had persistent infarct core iron 4 months after infarction with increasing rates across HbA1c levels (<5.7%: 33%, ≥5.7: 79%). Persistent infarct core iron was independently associated with ongoing dysglycaemia defined by HbA1c at 4 months (OR: 7.87 [95% CI: 2.60–23.78]; p < 0.001), after adjustment for patient characteristics and CMR parameters. The independent association was present even after exclusion of patients with diabetes (pre- and newly diagnosed, n = 16). ConclusionsIn STEMI patients treated with primary PCI, ongoing dysglycaemia defined by HbA1c is independently associated with persistent infarct core iron and a lower likelihood of iron resolution. These findings suggest a potential association between ongoing dysglycaemia and persistent infarct core iron, which warrants further investigation for therapeutic implications.

Thrombectomy for patients with a large infarct core: a study-level meta-analysis with trial sequential analysis.

The effectiveness and safety of endovascular treatment compared with medical management alone regarding outcomes for patients with a large infarct core remain uncertain. To juxtapose the clinical outcomes of thrombectomy versus the best medical care in patients with a large infarct core. Systematic review and meta-analysis. We conducted searches in PubMed, Cochrane, and Embase for articles published up until November 8, 2023. Randomized trials were selected for inclusion if they encompassed patients with large vessel occlusion and sizable strokes receiving thrombectomy. The primary outcome was functional outcomes at 3 months after pooling data using random-effects modeling. Safety outcomes included mortality at 3 months, symptomatic intracranial hemorrhage (SICH), and decompressive craniectomy. We performed a trial sequential analysis to balance type I and II errors. From 904 citations, we identified six randomized trials, involving a cohort of 1897 patients with a large ischemic region. Of these, 953 individuals underwent endovascular thrombectomy. At 3 months, thrombectomy was significantly correlated with better neurological prognosis, as evidenced by the increased odds of good functional outcomes (odds ratio (OR), 2.90; 95% confidence interval (CI), 2.08-4.05) and favorable functional outcomes (OR, 2.40; 95% CI, 1.86-3.09). Mortality rates did not demonstrably diminish as a consequence of the endovascular management (OR, 0.78; 95% CI, 0.58-1.06). However, the incidence of SICH was greater in the thrombectomy group compared to those with only medical treatment (5.5% vs 3.2%; OR, 1.77; 95% CI, 1.11-2.83). The application of trial sequential analysis yielded definitive evidence regarding favorable function outcomes and a shift in the distribution of modified Rankin scale scores at 3 months; however, others remained inconclusive. The results from most of the included trials display consistency. Meta-analysis of these six randomized trials offers high-quality evidence that thrombectomy significantly mitigates disability in patients with a large infarction, while also increasing the risk of SICH. PROSPERO, CRD42023480359.

Improving the impact of different input arteries on cerebral CT perfusion parameters and ischemic penumbra

This study aims to examine the impact of different input arteries on cerebral perfusion parameters and the volume of core infarction, ischemic area, and penumbra automatically measured by software in post-processing 256-slice CT brain perfusion images. Retrospective analysis was conducted on brain perfusion images of 58 patients who underwent 256-slice multidetector CT examination for cerebral infarction. Various input arteries, including bilateral internal carotid artery (ICA), bilateral middle cerebral artery (MCA), anterior cerebral artery (ACA), and basilar artery (BA), were selected for image processing and measurements. The volumes of core infarction, ischemic area, and penumbra were automatically calculated using software. Additionally, manual measurements were per-formed by experienced doctors. Perfusion parameters including cerebral blood volume (CBV), cerebral blood flow (CBF), mean transit time (MTT), and time to peak (TTP) were evaluated. The change of input artery resulted in a significant difference in CBF and MTT in the penumbra and normal brain tissue areas. However, no significant difference was observed in CBV, TTP, and perfusion parameters in the core infarct area. The volumes of core infarction acquired from different input arteries showed no significant difference. Nonetheless, significant differences were found in the volume of the ischemic area and the mismatched area. The selection of different input arteries affects CT cerebral perfusion parameter values and the automatic measurement of the ischemic area and penumbra by software. Thus, when performing post-processing of CT cerebral perfusion images, it is advisable to choose the thicker internal carotid artery on the healthy side as the input artery.

Revolutionizing the Management of Large-Core Ischaemic Strokes: Decoding the Success of Endovascular Therapy in the Recent Stroke Trials.

Endovascular therapy (EVT) has revolutionized the management of acute ischaemic strokes with large vessel occlusion, with emerging evidence suggesting its benefit also in large infarct core volume strokes. In the last two years, four randomised controlled trials have been published on this topic-RESCUE-Japan LIMIT, ANGEL-ASPECT, SELECT2 and TENSION, with overall results showing that EVT improves functional and neurological outcomes compared to medical management alone. This review aims to summarise the recent evidence presented by these four trials and highlight some of the limitations in our current understanding of this topic.