Anterior Circulation Proximal Occlusion Research Articles

Optimizing in-hospital triage for large vessel occlusion using a novel clinical scale (GAI2AA).

ObjectiveTo identify a proximal anterior circulation occlusion for effectively administering immediate mechanical thrombectomy by developing a novel, simple diagnostic scale to predict the occlusion, to compare its validity with available scales, and to assess its utility.MethodsTo develop a novel clinical scale, we retrospectively analyzed a cohort of 429 patients with acute ischemic stroke from a single center. The novel scale GAI2AA was applied to a prospective cohort of 259 patients from 3 stroke centers for external validation. The utility of the scale as an in-hospital triage was compared for the temporal factors of 158 patients with the occlusion.ResultsIn a scale-developmental phase, those with a proximal anterior circulation occlusion had significantly more frequent signs of hemispheric symptoms, including gaze palsy, aphasia, inattention, arm paresis, and atrial fibrillation. The GAI2AA scale was developed using consolidated hemispheric symptoms and was scored as follows: score = 2, arm paresis score = 1, and atrial fibrillation score = 1. A cutoff value ≥3 was optimal for the correlation between sensitivity (88%) and specificity (81%), with a C statistic of 0.90 (95% confidence interval 0.87–0.93). External validation indicated that discrimination was significantly better than or not different from that of available complex scales. Door-to-puncture time was significantly reduced (91 [82–111] vs 52 [32–75] minutes, p < 0.001).ConclusionThe GAI2AA scale showed high sensitivity and specificity when an optimal cutoff score was used and was useful as an in-hospital triage tool.

One-Year Healthcare Utilization for Patients That Received Endovascular Treatment Compared With Control.

Background and Purpose- Endovascular therapy has been shown to be highly efficacious based on 90-day modified Rankin Scale score. We examined actual daily healthcare utilization from stroke onset to 1 year afterward from the ESCAPE trial (Endovascular Treatment for Small Core and Anterior Circulation Proximal Occlusion With Emphasis on Minimizing CT to Recanalization Time) and registry data. Methods- We examined patients from Alberta, Canada, that was enrolled into the ESCAPE trial and the Quality Improvement and Clinical Research registry in the 2016/2017 fiscal year. Through data linkages to several administrative data sets, the daily location of each patient was assessed in various healthcare settings. Results- A total of 286 patients were analyzed, 52 patients were in the treatment arm, and 47 patients were in the control arm of the ESCAPE trial while 187 patients received endovascular therapy as usual care (2016/2017 fiscal year). The odds of a patient being out of a healthcare setting over 1 year was significantly higher when they received endovascular therapy: 3.46 (1.68-7.30) in ESCAPE trial patients and 2.00 (1.08-3.75) in the Quality Improvement And Clinical Research patients. Conclusions- Endovascular therapy significantly reduces healthcare utilization up to 1 year after a stroke.

Severe Stroke Patients With Left-Sided Occlusion of the Proximal Anterior Circulation Benefit More From Thrombectomy.

Background and Purpose: Endovascular thrombectomy improves the functional independence of patients with proximal anterior circulation occlusion. However, a subset of patients fail to benefit from thrombectomy procedures, the reasons for which remain poorly defined. In this study, we investigated whether the effectiveness of thrombectomy was affected by left- or right-sided occlusion among patients with similar stroke severities.Methods: Patients with proximal anterior circulation occlusion (internal carotid or M1 of middle cerebral artery) treated with the Solitaire stent retriever within 8 h of the onset of acute ischemic stroke were enrolled from the Yijishan Hospital of Wannan Medical College. Stroke severity was measured using the National Institutes of Health Stroke Scale (NIHSS) on admission. The functional outcomes were assessed using the modified Rankin scale (mRS) at 90 days.Results: We enrolled 174 patients including 90 left-sided occlusion and 84 right-sided occlusion. The NIHSS scores on admission were higher in the left-sided (median, 19; interquartile range, 16 to 20) compared to the right-sided occlusion group (median, 15, interquartile range, 13 to 18) (P < 0.001). Following adjustment for potential risk factors, patients with left-sided occlusion had higher rates of functional independence (mRS ≤ 2) and lower rates of mortality (mRS = 6) compared to the right-sided occlusion patients (39.5 vs. 19.6% and 28.9 vs. 47.8%, respectively) in the severe stroke group (NIHSS ≥ 15).Conclusions: In severe stroke patients with proximal anterior circulation occlusion, stent retriever thrombectomy within 8 h of the onset of symptoms provides more benefits to left-sided occlusion.

Lack of Consensus Among Stroke Experts on the Optimal Management of Patients With Acute Tandem Occlusion

Background and Purpose- In patients with acute stroke caused by tandem occlusion, the benefit of immediate revascularization (stenting) of the cervical internal carotid artery lesion during endovascular thrombectomy is uncertain. We sought to determine current practice patterns and whether consensus existed among physicians with stroke expertise. Methods- We distributed an online survey to stroke experts affiliated with the Canadian Stroke Consortium, the Canadian Interventional Neuro Group, the Society of Vascular and Interventional Neurology, and international ESCAPE trial (Endovascular Treatment for Small Core and Anterior Circulation Proximal Occlusion With Emphasis on Minimizing CT to Recanalization Times) collaborators. Questions were based on clinical scenarios, and multiple choice responses across a Likert-type scale were provided. The survey was sent out in September 2017. After 2 months, data were extracted and then analyzed using descriptive statistics. Results- Responses from 162 stroke experts were analyzed; most were stroke physicians (n=65, 40.1%) and neurointerventionalists (n=74, 45.7%), from Canada (n=95, 58.6%), the United States (n=42, 25.9%), and other countries (n=25, 15.4%). Over half (n=96, 59.3%) of respondents consider acute stenting of the cervical internal carotid artery as a treatment option, whereas 40.7% (n=66) would never use it. Most respondents (n=113, 69.8%) agree that there exists uncertainty about the optimal acute management of patients with tandem occlusion. A majority (n=88, 54.3%) of physicians surveyed would include patients in a randomized trial addressing this question. Conclusions- This survey shows high variability in practice about acute management of tandem occlusion. The existence of community equipoise underscores the importance of a randomized trial evaluating the benefit of acute internal carotid artery stenting in patients with tandem occlusion undergoing endovascular thrombectomy.

Deferral of Consent in Acute Stroke Trials.

Background and Purpose- The ESCAPE trial (The Endovascular Treatment for Small Core and Anterior Circulation Proximal Occlusion With Emphasis on Minimizing CT to Recanalization Times) was a multicentre, randomized controlled trial of endovascular thrombectomy versus standard care for patients with acute ischemic stroke that allowed patients to be enrolled with deferred consent. We investigated the knowledge and opinions of these patients or their authorized third parties about the consent process. Methods- All patients (or their authorized third parties) enrolled with deferral of consent in ESCAPE were invited to complete a 12-question survey within the first 4 days of enrollment and again at 90 days. Questions investigated knowledge of the ESCAPE trial and opinions on deferral of consent. Results- Of 56 patients enrolled with deferred consent, 33 (59%) completed the initial survey, and of these, 27 (81%) completed the 90-day follow-up. Enrollment with deferred consent was not associated with a significant difference in door-to-randomization times (50.5 versus 57 minutes; P=0.29) but allowed these 56 patients to participate in the trial. Only 52% of respondents understood that patients could be randomized to thrombectomy or standard care, although most understood the other basic principles of the trial. At baseline and at 90 days, respondents disagreed or strongly disagreed with deferred consent in acute stroke trials generally (82% and 78%) and in the ESCAPE trial specifically (93% and 91%). Conclusions- Respondents generally disagreed with the use of deferred consent for enrollment in the ESCAPE trial and in stroke trials more generally.

Comprehensive assessment of disability post-stroke using the newly developed miFUNCTION scale

The modified Rankin Scale (mRS) is the most widely used primary outcome measure in acute stroke trials. However, substantial interobserver variability impairs outcome assessment as well as reduces power of clinical trials. Guided by the International Classification of Functioning, Disability and Health, we developed a comprehensive, hierarchical assessment tool (miFUNCTION) to address the shortcomings of the modified Rankin Scale and deliver a more thorough understanding of disability following stroke. The initial construct validity of miFUNCTION was established in a pilot study of patients at an outpatient stroke prevention clinic that had been diagnosed with stroke within 60 days. To further assess criterion validity, miFUNCTION was compared against the modified Rankin Scale and other outcome measures within the Endovascular Treatment for Small Core and Anterior Circulation Proximal Occlusion With Emphasis on Minimizing CT to Recanalization Times (ESCAPE) trial. Logistic regression analysis with miFUNCTION as an outcome was used to demonstrate the beneficial effect of endovascular treatment. The pilot study showed moderate inter-observer agreement (k = 0.585, p < 0.005) but near perfect correlation between miFUNCTION and modified Rankin Scale (ρ = 0.821, p < 0.05). The correlation of miFUNCTION and modified Rankin Scale was near perfect again in the ESCAPE trial (ρ = 0.944). Effect size of the multivariable models using modified Rankin Scale (adjusted odds ratio: 3.45, 95% confidence interval: 2.05-5.78) and miFUNCTION (adjusted odds ratio: 3.32, 95% confidence interval: 1.99-5.55) as an outcome measure for the ESCAPE trial patients was similar. miFUNCTION is strongly associated with the degree of disability following stroke both in an outpatient setting and a clinical trial. Further work remains to assess sensitivity to change and to improve the inter-observer reliability of the scale.

Factors impacting on technical success in stroke thrombectomy: experience of a UK neuro-interventional unit

To investigate factors that could impact on recanalisation and reperfusion in patients undergoing mechanical thrombectomy and to assess the technical success over time. Two hundred consecutive patients who underwent thrombectomy for a proximal anterior circulation occlusion were dichotomised into equal groups (groups 1 and 2) based on the date that immediate access to emergency general anaesthesia (GA) commenced. Recanalisation success using thrombolysis in cerebral infarction (TICI) 2b/3 or TICI 2c/3 significantly improved in group 2 (67% versus 93%, p<0.0001; 52% versus 78%, p=0.0002). Symptomatic haemorrhage also reduced from 9% to 4%. Despite similar presentation Alberta Stroke Program Early (computed tomography) CT Scores (ASPECTS), post-procedural ASPECTS was significantly increased in group 2 (7; [interquartile range {IQR} 4-9] versus 8 [IQR 7-9]; p=0.0034). The number of patients with a post procedural ASPECTS of 8-10 increased (46% versus 64%, p=0.0155) and the difference in ASPECTS between pre- and post-thrombectomy CT was significantly lower (2 [IQR 1-4] versus 1 [IQR 0-2], p<0.0001). GA use increased from 8% to 56% (p=0.0001) as did use of distal aspiration (59% versus 87%, p=0.0001) mostly in combination with a stent-retriever. Failed access fell from 8% to 3%. When GA was used, successful recanalisation (TICI 2b/3) was achieved more frequently (90.5% versus 76.7%; OR 3.04, 1.2-7.69, p=0.0187). Technical results for thrombectomy are improving over time. Technique modification, operator experience, and judicious use of GA may be contributing.

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.

Angioplasty and stenting of adult onset Moya-moya disease

Abstract Moya moya is a disease that typically affects children and is treated with extra-cranial to intracranial bypass in suitable patients. We present an adult 28-year-old patient with Moya-moya disease who had a stepwise progression of the disease and was treated with angioplasty and stenting of the stenosis bilaterally. This novel treatment method allowed her posterior circulation sufficient time to collateralize the areas in the anterior circulation which had a deficient blood supply. After the procedure, the patient has been asymptomatic for the last 5 years despite developing proximal anterior circulation occlusions bilaterally. This is the first description of angioplasty and stenting in Moya-moya disease. Although this strategy does not treat the underlying cause, it is potentially effective temporizing measure that could allow the brain to develop alternative blood supply or allow a bypass operation time to mature in an urgent setting.

Combined Evaluation of Noncontrast CT ASPECTS and CT Angiography Collaterals Improves Detection of Large Infarcts in Proximal Artery Occlusive Stroke.

Imaging may identify patients with very large infarcts who are unlikely to benefit from intra-arterial therapy. Although computed tomography (CT) is widely used, it suffers from poor sensitivity. We sought to evaluate whether combined evaluation of noncontrast CT (NCCT) and CT angiography (CTA) collaterals would improve the detection of large infarcts. All patients with anterior circulation proximal artery occlusion and baseline CT, CTA, and magnetic resonance imaging (MRI) performed were identified. NCCT ASPECTS, CTA collateral score (CS), and diffusion-weighted imaging (DWI) lesion volume were determined. Receiver-operating characteristic analyses were performed to test the discrimination of NCCT ASPECTS 0-4, CTA malignant collaterals (CS = 0: absent collaterals in >50% of M2 territory), and the combination for DWI volume > 100 mL. Among 54 patients, mean age was 67 years; median NIHSS was 14. Occlusion locations were ICA terminus (18 [33%]), MCA M1 (20 [37%]), and M2 (16 [30%]). Median NCCT ASPECTS was 8; 8 (15%) had ASPECTS 0-4. Median CTA CS was 2; 9 (17%) were categorized as malignant. Median DWI lesion volume was 25 mL; 12 (22%) had lesions >100 mL. Individually, the CTA malignant collateral profile (98%) and NCCT ASPECTS 0-4 (100%) demonstrated high specificity for DWI lesion volume >100 mL, but had suboptimal sensitivity (both 67%). In the combined approach (CTA CS = 0 and/or NCCT ASPECTS ≤4), the sensitivity improved significantly to 92%, while maintaining high specificity (98%). Combined evaluation of NCCT ASPECTS and CTA collaterals identifies patients with infarcts >100 mL with high accuracy, and can improve patient selection using current CT techniques.

Computed Tomographic Perfusion Predicts Poor Outcomes in a Randomized Trial of Endovascular Therapy.

In the ESCAPE trial (Endovascular Treatment for Small Core and Anterior Circulation Proximal Occlusion with Emphasis on Minimizing CT to Recanalization Times), patients with large vessel occlusions and small infarct cores identified with computed tomography (CT)/CT angiography were randomized to endovascular therapy or standard of care. CT perfusion (CTP) was obtained in some cases but was not used to select patients. We tested the hypothesis that patients with penumbral CTP patterns have higher rates of good clinical outcome. All CTP data acquired in ESCAPE patients were analyzed centrally using a semiautomated perfusion threshold-based approach. A penumbral pattern was defined as an infarct core <70 mL, penumbral volume >15 mL, and a total hypoperfused volume:core volume ratio of >1.8. The primary outcome was good functional outcome at 90 days (modified Rankin Scale score, 0-2). CTP was acquired in 138 of 316 ESCAPE patients. Penumbral patterns were present in 116 of 128 (90.6%) of patients with interpretable CTP data. The rate of good functional outcome in penumbral pattern patients (53 of 114; 46%) was higher than that in nonpenumbral patients (2 of 12; 17%; P=0.041). In penumbral patients, endovascular therapy increased the likelihood of a good clinical outcome (34 of 58; 57%) compared with those in the control group (19 of 58; 33%; odds ratio, 2.68; 95% confidence interval, 1.25-5.76; P=0.011). Only 3 of 12 nonpenumbral patients were randomized to the endovascular group, preventing an analysis of treatment effect. The majority of patients with CTP imaging in the ESCAPE trial had penumbral patterns, which were associated with better outcomes overall. Patients with penumbra treated with endovascular therapy had the greatest odds of good functional outcome. Nonpenumbral patients were much less likely to achieve good outcomes.

Magnetic Resonance Imaging Selection for Endovascular Stroke Therapy: Workflow in the GOLIATH Trial.

The GOLIATH trial (General or Local Anesthesia in Intra-Arterial Therapy) compared infarct growth and outcome in patients undergoing endovascular therapy under either general anesthesia or conscious sedation. Magnetic resonance imaging was performed before and after the procedure to study infarct growth. In this post hoc analysis of GOLIATH, we aimed to characterize the workflow of patients undergoing magnetic resonance imaging selection before endovascular therapy. We randomized 128 patients with anterior circulation large vessel occlusion stroke within 6 hours of onset to either general anesthesia or conscious sedation (1:1 allocation). We studied workflow time intervals to examine whether magnetic resonance imaging conferred a time delay in treatment when compared with computed tomography-based studies that emphasized rapid workflow. Of 128 patients enrolled between March 2015 and February 2017, 65 were randomized to general anesthesia. Baseline demographic and clinical variables were balanced between the treatment arms. The median interval from scan to groin puncture was 56.5 minutes (interquartile range, 44.5-73.5) for all patients. The median interval from admission to groin puncture was 68 minutes (interquartile range, 54.5-87 minutes). Comparable intervals in recent randomized data were 51 minutes (interquartile range, 39-68) for scan to groin puncture in the ESCAPE trial (Endovascular Treatment for Small Core and Anterior Circulation Proximal Occlusion With Emphasis on Minimizing CT to Recanalization Times) and 90 minutes (interquartile range, 69-120 minutes) for door to groin puncture in the SWIFT-PRIME study (Solitaire With the Intention for Thrombectomy as Primary Endovascular Treatment). Workflow in GOLIATH demonstrates that magnetic resonance imaging selection for endovascular therapy can be accomplished rapidly and within a similar time frame as computed tomography-based selection. URL: https://www.clinicaltrials.gov. Unique identifier: NCT02317237.

Unknown-onset strokes with anterior circulation occlusion treated by thrombectomy after DWI-FLAIR mismatch selection.

The DAWN trial recently showed compelling evidence in treating late window and wake-up stroke patients with thrombectomy using a clinical-imaging mismatch. The aim was to evaluate the results of thrombectomy for unknown-onset strokes (UOS) treated in our centres after a diffusion weighted imaging/fluid attenuated inversion recovery (DWI-FLAIR) mismatch based selection. A multicentre, cohort study was performed of consecutive UOS treated by thrombectomy between 2012 and 2016. UOS with proximal anterior circulation occlusion discovered beyond 6 h from 'last seen normal' were compared with known-onset strokes (KOS) for whom thrombectomy was started within 6 h from onset. Time intervals were recorded from first time found abnormal. Results were adjusted for age, diabetes, hypertension, National Institutes of Health Stroke Scale, site of occlusion, DWI Alberta Stroke Programme Early CT Score, intravenous thrombolysis and use of general anaesthesia. Amongst 1246 strokes with anterior circulation occlusion treated by thrombectomy, 277 were UOS, with a 'last time seen well' beyond 6 h and DWI-FLAIR mismatch, and 865 were KOS who underwent groin puncture within 6 h. Favourable outcome was achieved less often in UOS than KOS patients (45.2% vs. 53.9%, P = 0.022). After pre-specified adjustment, this difference was not significant (adjusted relative risk 0.91; 95% confidence interval 0.80-1.04; P = 0.17). No differences were found in secondary outcomes. Time intervals from first found abnormal were significantly longer in UOS. Thrombectomy of UOS with anterior circulation occlusion and DWI-FLAIR mismatch appears to be as safe and efficient as thrombectomy of KOS within 6 h from onset. This pattern of imaging could be used for patient selection when time of onset is unknown.

Cost-effectiveness of mechanical thrombectomy within 6 hours of acute ischaemic stroke in China

ObjectivesEndovascular mechanical thrombectomy is an effective but expensive therapy for acute ischaemic stroke with proximal anterior circulation occlusion. This study aimed to determine the cost-effectiveness of mechanical thrombectomy in China,...

Abstract WP275: Cost-Effectiveness of Mechanical Thrombectomy of Ischemic Stroke

Background and Purpose: Endovascular mechanical thrombectomy is an effective but expensive therapy for acute ischemic stroke with proximal anterior circulation occlusion. This study aimed to determine the cost-effectiveness of mechanical thrombectomy in China, the largest developing country. Methods: A combination of decision tree and Markov model was developed to determine the cost-effectiveness of mechanical thrombectomy within 6 hours with IV tPA treatment within 4.5 hours versus IV tPA treatment alone. Outcomes and costs data were derived from the published literature and claims database. Efficacy data were derived from the patient-level pooled analyses of the 5 trials in 2015. Benefit was assessed by calculating the cost per quality-adjusted life-year (QALY) gained in the long term (30 years). One-way and probabilistic sensitivity analyses were performed to assess the uncertainty of the results. Results: The addition of mechanical thrombectomy compared with standard treatment alone yielded a lifetime gain of 0.934 QALYs at an additional cost of CNY 61,760 (US$ 9,500), resulting in a cost of CNY 66,100 (US$ 10,170) per QALY gained. Probabilistic sensitivity analysis showed that mechanical thrombectomy is cost-effective in 91.9% of the simulation runs at a willingness-to-pay threshold of CNY 125,700 (US$ 19,300) per QALY. Conclusions: Mechanical thrombectomy for acute ischemic stroke caused by proximal anterior circulation occlusion within 6 hours was cost-effective in China. This may be a reference to medical resources allocation for stroke treatment in low- and middle-income countries and the remote areas in the developing countries.

Abstract 115: CT Perfusion Identifies Patients with Poor Outcomes in The Endovascular Treatment for Small Core and Anterior Circulation Proximal Occlusion with Emphasis on Minimizing CT to Recanalization Times (ESCAPE) Trial

Background: In the ESCAPE trial, patients with large vessel occlusions and small infarct cores identified with CT/CT angiography were randomized to endovascular therapy or standard of care. CT Perfusion (CTP) was obtained in some cases, but was not utilized to select patients. We tested the hypothesis that patients with penumbral CTP patterns have higher rates of good clinical outcome. Methods: All CTP data acquired in ESCAPE patients was analyzed centrally using a semi-automated perfusion threshold based approach. A penumbral pattern was defined as an infarct core&lt;70 mL, penumbral volume &gt;15 mL, and a total hypoperfused volume:core volume ratio of &gt;1.8. The primary outcome was a good functional outcome at 90 days (mRS 0-2). Results: CTP was acquired in 138 of 316 ESCAPE patients. Motion degraded CTP images from 9 patients were excluded. Penumbral patterns were present in 110/129 (85.3%) of patients. The rate of good functional outcome in penumbral pattern patients (53/108; 49.1%) was higher than that in non-penumbral patients (3/19; 15.8%, p=0.011). In penumbral patients, endovascular therapy increased the likelihood of good outcome (35/58; 60.3%) over those in the control group (18/50; 36%, OR=2.71, p=0.013). Only 4 of 19 non-penumbral patients were randomized to the endovascular group, preventing an analysis of treatment effect. Conclusion: The majority of patients with CTP imaging in the ESCAPE trial had penumbral patterns, which were associated with better outcomes overall. Patients with penumbra treated with endovascular therapy had the greatest odds of good functional outcome. Non-penumbral patients were much less likely to achieve good outcomes.

Abstract WP4: Age and NIHSS score Predict Outcome in Patients With Mild Stroke and Proximal Large Vessel Occlusion

Background: Current guidelines recommend mechanical thrombectomy for patients with anterior circulation proximal large vessel occlusion (LVO), NIHSS≥ 6, within 6 hours from symptom onset, with a NCCT ASPECTS of 6 or higher. It remains unclear whether patients with NIHSS &lt; 6 and LVO should also undergo mechanical thrombectomy. The benefit of intervention, associated risk and predictors of outcome in this patient population has not been studied. We sought to determine the natural history and predictors of good outcome in patients NIHSS&lt;6 and evidence of LVO who did not undergo mechanical thrombectomy. Methods: We abstracted data from our ischemic stroke prospective database and included patients with NIHSS &lt; 6 and presence of proximal large vessel occlusion admitted between January 1 st , 2015 and April 30 th , 2017. The outcome, 90-day mRS, was collected via a phone call at 90 days. Patients were divided into two groups: good outcome (90-day mRS 0-1) and poor outcome (90-day mRS 2-6). We compared baseline demographics, treatments, neuroimaging data (ASPECTS score), and vascular imaging findings (location of occlusion, collateral score: poor, good, and excellent) between the two groups. P-value &lt; 0.05 was considered significant. Results: A total of 68 patients were identified; 50/68 did not undergo mechanical thrombectomy; out of which only 25/50 (50%) had a good 90-day outcome. Patients with a good outcome were younger (Mean ± SD, 69.3 ±3.2 vs 76 ± 2.2 years of age, p=0.033) and had a lower median admission NIHSS score (3 vs. 4, p=0.026).There was a trend towards good outcome with ICA and M1- MCA occlusion when compared to other locations but this was not statistically significant. Other variables also did not achieve statistical significance. Conclusion: Younger age and lower NIHSS predict good functional outcome in patients with LVO and mild deficits. Larger prospective studies are needed to verify our findings and explore the role of mechanical thrombectomy in patients who might be at risk of poor outcome.

Abstract WMP1: Eligibility for Endovascular Trial Enrollment in the 6-24 Hour Time Window: Analysis of a Single Comprehensive Stroke Center

Background and Purpose: Recent completion of the DAWN trial supports the benefit of endovascular therapy in patients presenting in the 6-24 hour time window with anterior circulation large vessel occlusions. The scope and impact of these results on clinical practice remain unknown. Methods: A retrospective review of ischemic stroke admissions to a single comprehensive stroke center was performed during the enrollment period (November 2015-February 2017) to identify patients meeting criteria for DAWN eligibility. Patients presenting beyond 6 hours were further investigated to clarify reasons for trial exclusion. Results: Of the 2667 acute ischemic stroke patients admitted within the study period, 30% (n=792) presented within the 6-24 hour time window and 33% (890) had an NIHSS of 10 or higher. Of the 11% (n=298) patients meeting both criteria, trial exclusion occurred due to: absence of large vessel occlusion (LVO) (48%,n=143), presence of sub-occlusive, distal or posterior circulation LVO (18%, n=54), large core infarct or ASPECT &lt; 7 (25%, n=73) or absence of clinical core mismatch (5%, n=16), mRS &gt;1 (13%, n=38). There were 45 patients who met all DAWN criteria. Conclusions: Of all acute ischemic stroke patients presenting to a single CSC, 1.7% of patients qualified for DAWN clinical trial enrollment. Of patients with proximal anterior circulation occlusion presenting in the 6- 24 hour time window with NIHSS of 10 or higher , 29% were eligible for treatment based on DAWN criteria. These data predict an increase in thrombectomy utilization with important implications for Comprehensive Stroke Center resource utilization and stroke systems of care.

Abstract WMP3: Unknown Onset Strokes With Anterior Circulation Occlusion Treated by Thrombectomy After DWI-FLAIR Mismatch Selection

Background and Purpose: Unknown-onset strokes (UOS) have often been considered seperately from known-onset strokes (KOS), since emergency recanalization treatments are based on a time-window. Improvement in imaging-based selection and the advent of endovascular thrombectomy may lead us to reconsider this practice. Methods: We performed a retrospective, multicenter, cohort study of consecutive UOS treated by thrombectomy between December 2012 and December 2016. We compared UOS with proximal anterior circulation occlusion discovered beyond 6 hours from “last seen normal” with KOS for whom thrombectomy was started within 6 hours from onset. Time intervals from first found abnormal were recorded and compared with time intervals of KOS. Results were adjusted for age, initial National Institutes of Health Stroke Scale score, site of occlusion, diffusion weighted imaging Alberta Stroke Program Early CT Score, intravenous thrombolysis and use of general anesthesia. Results: Among 1246 strokes with anterior circulation occlusion treated by thrombectomy, 277 were UOS, with a “last time seen well” beyond 6 hours and DWI-FLAIR mismatch, and 865 were KOS who underwent groin puncture within 6 hours. Favorable outcome was achieved less often in UOS than KOS patients (45.2% vs. 53.9%, p=0.022). After pre-specified adjustment, this difference was not significant (adusted relative risk=0.91; 95%CI, 0.80 to 1.04; p=0.17). No differences in secondary outcomes were found except a marginal difference for excellent outcome (adjusted relative risk=0.83; 95%CI, 0.69 to 1.00; p=0.052), Time intervals from “first found abnormal” were significantly longer in UOS. Conclusion: Endovascular treatment of unknown-onset strokes with anterior circulation occlusion and DWI-FLAIR mismatch appears to be as safe and efficient as endovascular treatment of known-onset strokes within 6 hours from onset. This pattern of imaging could be used for patient selection when time of onset is unknown.

MR Perfusion to Determine the Status of Collaterals in Patients with Acute Ischemic Stroke: A Look Beyond Time Maps.

Patients with acute stroke with robust collateral flow have better clinical outcomes and may benefit from endovascular treatment throughout an extended time window. Using a multiparametric approach, we aimed to identify MR perfusion parameters that can represent the extent of collaterals, approximating DSA. Patients with anterior circulation proximal arterial occlusion who had baseline MR perfusion and DSA were evaluated. The volume of arterial tissue delay (ATD) at thresholds of 2-6 seconds (ATD2-6 seconds) and >6 seconds (ATD>6 seconds) in addition to corresponding values of normalized CBV and CBF was calculated using VOI analysis. The association of MR perfusion parameters and the status of collaterals on DSA were assessed by multivariate analyses. Receiver operating characteristic analysis was performed. Of 108 patients reviewed, 39 met our inclusion criteria. On DSA, 22/39 (56%) patients had good collaterals. Patients with good collaterals had significantly smaller baseline and final infarct volumes, smaller volumes of severe hypoperfusion (ATD>6 seconds), larger volumes of moderate hypoperfusion (ATD2-6 seconds), and higher relative CBF and relative CBV values than patients with insufficient collaterals. Combining the 2 parameters into a Perfusion Collateral Index (volume of ATD2-6 seconds × relative CBV2-6 seconds) yielded the highest accuracy for predicting collateral status: At a threshold of 61.7, this index identified 15/17 (88%) patients with insufficient collaterals and 22/22 (100%) patients with good collaterals, for an overall accuracy of 94.1%. The Perfusion Collateral Index can predict the baseline collateral status with 94% diagnostic accuracy compared with DSA.