Mehdi Bouslama

Endovascular Treatment for Patients With Acute Stroke Who Have a Large Ischemic Core and Large Mismatch Imaging Profile

Importance Endovascular therapy (ET) is typically not considered for patients with large baseline ischemic cores (irreversibly injured tissue). Computed tomographic perfusion (CTP) imaging may identify a subset of patients with large ischemic cores who remain at risk for significant infarct expansion and thus could still benefit from reperfusion to reduce their degree of disability. Objective To compare the outcomes of patients with large baseline ischemic cores on CTP undergoing ET with the outcomes of matched controls who had medical care alone. Design, Setting, and Participants A matched case-control study of patients with proximal occlusion after stroke (intracranial internal carotid artery and/or middle cerebral artery M1 and/or M2) on computed tomographic angiography and baseline ischemic core greater than 50 mL on CTP at a tertiary care center from May 1, 2011, through October 31, 2015. Patients receiving ET and controls receiving medical treatment alone were matched for age, baseline ischemic core volume on CTP, and glucose levels. Baseline characteristics and outcomes were compared. Main Outcomes and Measures The primary outcome measure was the shift in the degree of disability among the treatment and control groups as measured by the modified Rankin Scale (mRS) (with scores ranging from 0 [fully independent] to 6 [dead]) at 90 days. Results Fifty-six patients were matched across 2 equally distributed groups (mean [SD] age, 62.25 [13.92] years for cases and 58.32 [14.79] years for controls; male, 13 cases [46%] and 14 controls [50%]). Endovascular therapy was significantly associated with a favorable shift in the overall distribution of 90-day mRS scores (odds ratio, 2.56; 95% CI, 2.50-8.47; P = .04), higher rates of independent outcomes (90-day mRS scores of 0-2, 25% vs 0%; P = .04), and smaller final infarct volumes (mean [SD], 87 [77] vs 242 [120] mL; P < .001). One control (4%) and 2 treatment patients (7%) developed a parenchymal hematoma type 2 (P > .99). The rates of hemicraniectomy (2 [7%] vs 6 [21%]; P = .10) and 90-day mortality (7 [29%] vs 11 [48%]; P = .75) were numerically lower in the intervention arm. Sensitivity analysis for patients with a baseline ischemic core greater than 70 mL (12 pairs) revealed a significant reduction in final infarct volumes (mean [SD], 110 [65] vs 319 [147] mL; P < .001) but only a nonsignificant improvement in the overall distribution of mRS scores favoring the treatment group (P = .18). All 11 patients older than 75 years had poor outcomes (mRS score >3) at 90 days. Conclusions and Relevance In properly selected patients, ET appears to benefit patients with large core and large mismatch profiles. Future prospective studies are warranted.

Cervical Carotid Pseudo-Occlusions and False Dissections: Intracranial Occlusions Masquerading as Extracranial Occlusions

Background and Purpose— Pseudo-occlusion (PO) of the cervical internal carotid artery (ICA) refers to an isolated occlusion of the intracranial ICA that appears as an extracranial ICA occlusion on computed tomography angiography (CTA) or digital subtraction angiography because of blockage of distal contrast penetration by a stagnant column of unopacified blood. We aim to better characterize this poorly recognized entity. Methods— Retrospective review of an endovascular database (2010–2015; n=898). Only patients with isolated intracranial ICA occlusions as confirmed by angiographic exploration were included. CTA and digital subtraction angiography images were categorized according to their apparent site of occlusion as (1) extracranial ICA PO or (2) discernible intracranial ICA occlusion. Results— Cervical ICA PO occurred in 21/46 (46%) patients on CTA (17 proximal cervical; 4 midcervical). Fifteen (71%) of these patients also had PO on digital subtraction angiography. A flame-shaped PO mimicking a carotid dissection was seen in 7 (33%) patients on CTA and in 6 (29%) patients on digital subtraction angiography. Patients with and without CTA PO had similar age (64.8±17.1 versus 60.2±15.7 years; P=0.35), sex (male, 47% versus 52%; P=1.00), and intravenous tissue-type plasminogen activator use (38% versus 40%; P=1.00). The rates of modified Treatment In Cerebral Ischemia 2b-3 reperfusion were 71.4% in the PO versus 100% in the non-PO cohorts (P<0.01). The rates of parenchymal hematoma, 90-day modified Rankin Scale score 0–2, and 90-day mortality were 4.8% versus 8% (P=0.66), 40% versus 66.7% (P=0.12), and 25% versus 21% (P=0.77) in PO versus non-PO patients, respectively. Multivariate analysis indicated that PO patients had lower chances of modified Treatment In Cerebral Ischemia 3 reperfusion (odds ratio 0.14; 95% confidence interval 0.02–0.70; P=0.01). Conclusions— Cervical ICA PO is a relatively common entity and may be associated with decreased reperfusion rates.

The FAST-ED App: A Smartphone Platform for the Field Triage of Patients With Stroke

Background and Purpose— The Emergency Medical Services field triage to stroke centers has gained considerable complexity with the recent demonstration of clinical benefit of endovascular treatment for acute ischemic stroke. We sought to describe a new smartphone freeware application designed to assist Emergency Medical Services professionals with the field assessment and destination triage of patients with acute ischemic stroke. Methods— Review of the application’s platform and its development as well as the different variables, assessments, algorithms, and assumptions involved. Results— The FAST-ED (Field Assessment Stroke Triage for Emergency Destination) application is based on a built-in automated decision-making algorithm that relies on (1) a brief series of questions assessing patient’s age, anticoagulant usage, time last known normal, motor weakness, gaze deviation, aphasia, and hemineglect; (2) a database of all regional stroke centers according to their capability to provide endovascular treatment; and (3) Global Positioning System technology with real-time traffic information to compute the patient’s eligibility for intravenous tissue-type plasminogen activator or endovascular treatment as well as the distances/transportation times to the different neighboring stroke centers in order to assist Emergency Medical Services professionals with the decision about the most suitable destination for any given patient with acute ischemic stroke. Conclusions— The FAST-ED smartphone application has great potential to improve the triage of patients with acute ischemic stroke, as it seems capable to optimize resources, reduce hospital arrivals times, and maximize the use of both intravenous tissue-type plasminogen activator and endovascular treatment ultimately leading to better clinical outcomes. Future field studies are needed to properly evaluate the impact of this tool in stroke outcomes and resource utilization.

Automated CT Perfusion Ischemic Core Volume and Noncontrast CT ASPECTS (Alberta Stroke Program Early CT Score) Correlation and Clinical Outcome Prediction in Large Vessel Stroke

Background and Purpose— The semiquantitative noncontrast CT Alberta Stroke Program Early CT Score (ASPECTS) and RAPID automated computed tomography (CT) perfusion (CTP) ischemic core volumetric measurements have been used to quantify infarct extent. We aim to determine the correlation between ASPECTS and CTP ischemic core, evaluate the variability of core volumes within ASPECTS strata, and assess the strength of their association with clinical outcomes. Methods— Review of a prospective, single-center database of consecutive thrombectomies of middle cerebral or intracranial internal carotid artery occlusions with pretreatment CTP between September 2010 and September 2015. CTP was processed with RAPID software to identify ischemic core (relative cerebral blood flow<30% of normal tissue). Results— Three hundred and thirty-two patients fulfilled inclusion criteria. Median age was 66 years (55–75), median ASPECTS was 8 (7–9), whereas median CTP ischemic core was 11 cc (2–27). Median time from last normal to groin puncture was 5.8 hours (3.9–8.8), and 90-day modified Rankin scale score 0 to 2 was observed in 54%. The correlation between CTP ischemic core and ASPECTS was fair (R=−0.36; P<0.01). Twenty-six patients (8%) had ASPECTS <6 and CTP core ⩽50 cc (37% had modified Rankin scale score 0–2, whereas 29% were deceased at 90 days). Conversely, 27 patients (8%) had CTP core >50 cc and ASPECTS ≥6 (29% had modified Rankin scale 0–2, whereas 21% were deceased at 90 days). Moderate correlations between ASPECTS and final infarct volume (R=−0.42; P<0.01) and between CTP ischemic core and final infarct volume (R=0.50; P<0.01) were observed; coefficients were not significantly influenced by the time from stroke onset to presentation. Multivariable regression indicated ASPECTS ≥6 (odds ratio 4.10; 95% confidence interval, 1.47–11.46; P=0.01) and CTP core ⩽50 cc (odds ratio 3.86; 95% confidence interval, 1.22–12.15; P=0.02) independently and comparably predictive of good outcome. Conclusions— There is wide variability of CTP-derived core volumes within ASPECTS strata. Patient selection may be affected by the imaging selection method.

Stroke etiology and collaterals: atheroembolic strokes have greater collateral recruitment than cardioembolic strokes

Chronic hypoperfusion from athero‐stenotic lesions is thought to lead to better collateral recruitment compared to cardioembolic strokes. It was sought to compare collateral flow in stroke patients with atrial fibrillation (AF) versus stroke patients with cervical atherosclerotic steno‐occlusive disease (CASOD).

Selection Paradigms for Large Vessel Occlusion Acute Ischemic Stroke Endovascular Therapy

Background: Optimal patient selection methods for thrombectomy in large vessel occlusion stroke (LVOS) are yet to be established. We sought to evaluate the ability of different selection paradigms to predict favorable outcomes. Methods: Review of a prospectively collected database of endovascular patients with anterior circulation LVOS, adequate CT perfusion (CTP), National Institutes of Health Stroke Scale (NIHSS) ≥10 from September 2010 to March 2016. Patients were retrospectively assessed for thrombectomy eligibility by 4 mismatch criteria: Perfusion-Imaging Mismatch (PIM): between CTP-derived perfusion defect and ischemic core volumes; Clinical-Core Mismatch (CCM): between age-adjusted NIHSS and CTP core; Clinical-ASPECTS Mismatch (CAM-1): between age-adjusted NIHSS and ASPECTS; Clinical-ASPECTS Mismatch (CAM-2): between NIHSS and ASPECTS. Outcome measures were inclusion rates for each paradigm and their ability to predict good outcomes (90-day modified Rankin Scale 0-2). Results: Three hundred eighty-four patients qualified. CAM-2 and CCM had higher inclusion (89.3 and 82.3%) vs. CAM-1 (67.7%) and PIM (63.3%). Proportions of selected patients were statistically different except for PIM and CAM-1 (p = 0.19), with PIM having the highest disagreement. There were no differences in good outcome rates between PIM(+)/PIM(-) (52.2 vs. 48.5%; p = 0.51) and CAM-2(+)/CAM-2(-) (52.4 vs. 38.5%; p = 0.12). CCM(+) and CAM-1(+) had higher rates compared to nonselected counterparts (53.4 vs. 38.7%, p = 0.03; 56.6 vs. 38.6%; p = 0.002). The abilities of PIM, CCM, CAM-1, and CAM-2 to predict outcomes were similar according to the c-statistic, Akaike and Bayesian information criterion. Conclusions: For patients with NIHSS ≥10, PIM appears to disqualify more patients without improving outcomes. CCM may improve selection, combining a high inclusion rate with optimal outcome discrimination across (+) and (-) patients. Future studies are warranted.

Automated CT Perfusion Ischemic Core Volume and Noncontrast CT ASPECTS: Correlation and Clinical Outcome Prediction in Large Vessel Stroke

Background and Purpose— The semiquantitative noncontrast CT Alberta Stroke Program Early CT Score (ASPECTS) and RAPID automated computed tomography (CT) perfusion (CTP) ischemic core volumetric measurements have been used to quantify infarct extent. We aim to determine the correlation between ASPECTS and CTP ischemic core, evaluate the variability of core volumes within ASPECTS strata, and assess the strength of their association with clinical outcomes. Methods— Review of a prospective, single-center database of consecutive thrombectomies of middle cerebral or intracranial internal carotid artery occlusions with pretreatment CTP between September 2010 and September 2015. CTP was processed with RAPID software to identify ischemic core (relative cerebral blood flow<30% of normal tissue). Results— Three hundred and thirty-two patients fulfilled inclusion criteria. Median age was 66 years (55–75), median ASPECTS was 8 (7–9), whereas median CTP ischemic core was 11 cc (2–27). Median time from last normal to groin puncture was 5.8 hours (3.9–8.8), and 90-day modified Rankin scale score 0 to 2 was observed in 54%. The correlation between CTP ischemic core and ASPECTS was fair (R=−0.36; P<0.01). Twenty-six patients (8%) had ASPECTS <6 and CTP core ⩽50 cc (37% had modified Rankin scale score 0–2, whereas 29% were deceased at 90 days). Conversely, 27 patients (8%) had CTP core >50 cc and ASPECTS ≥6 (29% had modified Rankin scale 0–2, whereas 21% were deceased at 90 days). Moderate correlations between ASPECTS and final infarct volume (R=−0.42; P<0.01) and between CTP ischemic core and final infarct volume (R=0.50; P<0.01) were observed; coefficients were not significantly influenced by the time from stroke onset to presentation. Multivariable regression indicated ASPECTS ≥6 (odds ratio 4.10; 95% confidence interval, 1.47–11.46; P=0.01) and CTP core ⩽50 cc (odds ratio 3.86; 95% confidence interval, 1.22–12.15; P=0.02) independently and comparably predictive of good outcome. Conclusions— There is wide variability of CTP-derived core volumes within ASPECTS strata. Patient selection may be affected by the imaging selection method.

Computed Tomographic Perfusion Selection and Clinical Outcomes After Endovascular Therapy in Large Vessel Occlusion Stroke

Background and Purpose— Different imaging paradigms have been used to select patients for endovascular therapy in stroke. We sought to determine whether computed tomographic perfusion (CTP) selection improves endovascular therapy outcomes compared with noncontrast computed tomography alone. Methods— Review of a prospectively collected registry of anterior circulation stroke patients undergoing stent-retriever thrombectomy at a tertiary care center between September 2010 and March 2016. Patients undergoing CTP were compared with those with noncontrast computed tomography alone. The primary outcome was the shift in the 90-day modified Rankin scale (mRS). Results— A total of 602 patients were included. CTP-selected patients (n=365, 61%) were younger (P=0.02) and had fewer comorbidities. CTP selection (n=365, 61%) was associated with a favorable 90-day mRS shift (adjusted odds ratio [aOR]=1.49; 95% confidence interval [CI], 1.06–2.09; P=0.02), higher rates of good outcomes (90-day mRS score 0–2: 52.9% versus 40.4%; P=0.005), modified Thrombolysis in Cerebral Infarction-3 reperfusion (54.8% versus 40.1%; P<0.001), smaller final infarct volumes (24.7 mL [9.8–63.1 mL] versus 34.6 mL [13.1–88 mL]; P=0.017), and lower mortality (16.6% versus 26.8%; P=0.005). When matched on age, National Institutes of Health Stroke Scale (NIHSS) score, and glucose (n=424), CTP remained associated with a favorable 90-day mRS shift (P=0.016), lower mortality (P=0.02), and higher rates of reperfusion (P<0.001). CTP better predicted functional outcomes in patients presenting after 6 hours (as assessed by comparison of logistic regression models: Akaike information criterion: 199.35 versus 287.49 and Bayesian information criterion: 196.71 versus 283.27) and those with an Alberta Stroke Program Early Computed Tomography Score ⩽7 (Akaike information criterion: 216.69 versus 334.96 and Bayesian information criterion: 213.6 versus 329.94). Conclusions— CTP selection is associated with a favorable mRS shift in patients undergoing stent-retriever thrombectomy. Future prospective studies are warranted.

Remote aspiration thrombectomy in large vessel acute ischemic stroke

The use of balloon guide catheters in acute ischemic stroke intervention has been associated with improved reperfusion rates and clinical outcomes. This technique acts by promoting flow arrest and subsequent reversal to capture the thrombus debris that may be generated during the clot retrieval process. However, to the best of our knowledge, the use of BGC to remotely aspirate and remove intracranial thrombus has not been previously described. We report a three case series of patients with acute ischemic stroke from supraclinoidal internal carotid artery occlusions treated with remote aspiration thrombectomy through a BGC placed at the cervical internal carotid artery, leading to complete reperfusion without the need for intracranial catheterization. Remote thrombectomy in the setting of intracranial internal carotid artery occlusion may constitute a relatively fast and inexpensive initial thrombectomy maneuver. Further investigation is warranted.

Thrombectomy versus medical management for large vessel occlusion strokes with minimal symptoms: an analysis from STOPStroke and GESTOR cohorts

Introduction It remains unclear whether patients presenting with large vessel occlusion strokes and mild symptoms benefit from thrombectomy. Objective To compare outcomes of endovascular therapy versus medical management in patients with large vessel occlusion strokes and National Institute of Health Stroke Scale (NIHSS) score ≤5. Methods This was a retrospective analysis combining two large prospectively collected datasets including patients with (1) admission NIHSS score ≤5, (2) premorbid modified Rankin Scale (mRS) score 0–2, and (3) middle cerebral-M1/M2, intracranial carotid, anterior cerebral or basilar artery occlusions. Groups receiving (1) endovascular treatment and (2) medical management were compared. The primary and secondary outcome measures were NIHSS shift (discharge NIHSS minus admission NIHSS) and the rates of mRS 0–2 at discharge and 3–6 months, respectively. Univariate, multivariate, and matched analyses were performed. Results Eighty-eight patients received medical management and 30 thrombectomy. Multivariable analysis indicated thrombectomy was the only predictor of favorable NIHSS shift (β −3.7, 95% CI −6.0 to −1.5, p=0.02), as well as independence at discharge (β −21.995% CI −41.4to −20.8, p<0.01) and 3–6-month follow-up (β −21.1, 95% CI −39.1 to −19.7, p<0.01). A matched analysis (based on age, baseline NIHSS and intravenous tissue plasminogen activator use) produced 26 pairs. Endovascular therapy was statistically associated with lower NIHSS at discharge (p=0.04), favorable NIHSS shift (p=0.03), and increased independence rates at discharge (p=0.03) and 3–6-month follow-up (p=0.04). Conclusion In patients presenting with minimal stroke symptoms (NIHSS score ≤5) and large vessel occlusion strokes, mechanical thrombectomy appears to be associated with a favorable shift of NIHSS at discharge, as well as higher rates of independence at discharge and long-term follow-up. Confirmatory prospective studies are warranted.