Posterior Circulation Large Vessel Occlusion Research Articles

First pass effect in posterior circulation occlusions: Analysis from the CICAT registry.

The first pass effect (FPE) is an independent predictor of functional independence in patients with large vessel occlusion in anterior circulation ischemic strokes. However, whether it predicts outcome in posterior circulation large vessel occlusion (PC-LVO) is uncertain. We aimed to study the frequency, characteristics, and predictors of FPE and its association with clinical outcomes in PC-LVO. We performed an analysis from the prospective CICAT Registry. All patients with PC-LVO who underwent endovascular therapy between January 2016 and January 2020 were included. A centrally assessed clinical follow-up was performed at 3 months by blinded investigators. FPE was defined as the achievement of modified Thrombolysis In Cerebral Infarction 3 in a single pass of the endovascular thrombectomy device, and multi-pass effect (MPE) if it was achieved in more than one pass. A multivariable analysis was performed to identify whether FPE is an independent predictor of functional independence defined as a modified Rankin Score of 0-2. We analyzed data from 265 patients in who FPE was achieved in 105 (39.6%). Patients with FPE were more likely to achieve functional independence compared to the non-FPE group (52.4% vs 25.1%, p < .001) and the MPE group (52.4% vs 26.7%, p < .001). FPE was independently associated with functional independence (adjusted odds ratio (aOR): 2.10, 95% confidence interval (CI) 1.01-4.37) but MPE was not (aOR: 0.92, 95% CI 0.40-2.13). Independent predictors of FPE were the use of direct aspiration, embolic mechanism of stroke, and the absence of general anesthesia (GA) use. FPE is an independent predictor of functional independence in PC-LVO and was associated with a significantly better outcome than MPE.

Endovascular Therapy Versus Medical Therapy Alone for Basilar Artery Stroke: A Systematic Review and Meta‐Analysis Through Nested Knowledge

BackgroundEndovascular thrombectomy (EVT) is an effective treatment for acute ischemic stroke attributable to the anterior circulation large‐vessel occlusion. Randomized trials of patients with posterior circulation large‐vessel occlusion (PC‐LVO) have failed to show a benefit of EVT over medical therapy (MEDT). We performed a systematic review and meta‐analysis to understand better whether EVT is beneficial for PC‐LVO.MethodsUsing the Nested Knowledge AutoLit living review platform, we identified randomized control trials and prospective studies that reported functional outcomes in patients with PC‐LVO treated with EVT versus MEDT. The primary outcome variable was 90‐day modified Rankin scale score of 0 to 3, and secondary outcome variables included 90‐day modified Rankin scale score of 0 to 2, 90‐day mortality, and rate of symptomatic intracranial hemorrhage. A separate random effects model was fit for each outcome measure to calculate pooled odds ratios.ResultsThree studies with 1248 patients, 860 in the EVT arm and 388 in the MEDT arm, were included in the meta‐analysis. The favorable outcome rate (modified Rankin scale score of 0–3) in patients undergoing EVT was 39.9% (95% CI, 30.6%–50.1%) versus 24.5% in patients undergoing MEDT (95% CI, 9.6%–49.8%). Patients undergoing EVT had higher modified Rankin scale score of 0 to 2 rates (31.8% [95% CI, 25.7%–38.5%] versus 19.7% [95% CI, 7.4%–42.7%]) and lower mortality (42.1% [95% CI, 35.9%–48.6%] versus 52.8% [95% CI, 33.3%–71.5%]) compared with patients undergoing MEDT, but neither result was statistically significant. Patients undergoing EVT were more likely to develop symptomatic intracranial hemorrhage (odds ratio, 10.36; 95% CI, 3.92–27.40).ConclusionsEVT treatment of PC‐LVO trended toward superior functional outcomes and reduced mortality compared with MEDT despite a trend toward increased symptomatic intracranial hemorrhage in patients undergoing EVT. Existing randomized and prospective studies are insufficiently powered to demonstrate a benefit of EVT over MEDT in patients with PC‐LVO.

Abstract WP166: Endovascular Stroke Therapy For Posterior Circulation Ischemic Stroke Has Diminishing Benefits With Number Of Retrieval Attempts

Introduction: The relationship between pass number during endovascular therapy (EVT) and outcomes in anterior circulation large vessel occlusion (LVO) acute ischemic stroke (AIS) has been well studied. However, the association between number of thrombectomy attempts and outcomes for patients with posterior circulation LVO remains undetermined. Methods: From our prospective multi-institutional registry including 4 comprehensive stroke centers in the Houston area, we identified consecutive LVO AIS patients who underwent EVT (01/2018-06/2021). The number of thrombectomy passes and per-pass reperfusion grades (TICI) were recorded at time of the EVT procedure. The primary outcome was the effect of number of passes on functional independence (modified Rankin Scale 0-2) at 90 days. Secondary outcomes included likelihood of attaining substantial reperfusion (TICI ≥2b). Results: Among 894 LVO AIS patients who underwent EVT, median age was 68 [IQR 58-78], 49% were female, and median NIHSS was 16 [IQR 11-21]. Of this cohort, 86 had posterior circulation LVO including 65 with basilar artery occlusion and 9 vertebral artery. The diminishing benefit on reperfusion and functional outcome after additional EVT passes was similar for anterior and posterior circulation AIS (Figure 1). Among patients with posterior circulation LVO, successful reperfusion with fewer passes was associated with greater likelihood of good outcomes (41.9% vs 6.7% mRS 0-2 with 1-2 vs ≥3, p=0.012). The likelihood of good outcomes with 1-2 passes for patients with posterior circulation LVO was comparable to patients with anterior circulation LVO (41.9% vs 40.2%, p=0.164). Conclusions: Similar to patients with anterior circulation LVO, patients with posterior circulation LVO undergoing EVT are more likely to achieve functional independence with successful reperfusion in fewer EVT attempts. Overall clinical outcomes are significantly better with fewer passes regardless of occlusion location.

Abstract TP147: Endovascular Therapy Versus Medical Therapy Alone For Basilar Artery Stroke: A Systematic Review And Meta-analysis Through Nested Knowledge

Background and Purpose: Endovascular thrombectomy (EVT) is an effective treatment for acute ischemic stroke (AIS) due to large vessel occlusion of the anterior circulation (AC-LVO). Randomized trials of posterior circulation large vessel occlusion (PC-LVO) patients have failed to show a benefit of EVT over medical therapy (MEDT). We performed a systematic review and meta-analysis to understand better whether EVT is beneficial for PC-LVO. Methods: Using the Nested Knowledge AutoLit living review platform, we identified randomized control trials and prospective studies that reported functional outcomes in patients with PC-LVO treated with EVT versus MEDT. The primary outcome variable was 90-day modified Rankin Scale (mRS) 0-3, and secondary outcome variables included 90-day mRS 0-2, 90-day mortality, and rate of symptomatic intracranial hemorrhage (sICH). A separate random effects model was fit for each outcome measure to calculate pooled odds ratios. Results: Three studies with 1,248 patients, 860 in the EVT arm and 388 in the MEDT arm, were included in the meta-analysis. The favorable outcome rate (mRS 0-3) in EVT patients was 39.9% (95% CI: 30.6-50.1%) versus 24.5% in MEDT patients (95% CI: 9.6-49.8%). EVT patients had higher mRS 0-2 rates (31.8% [95% CI: 25.7-38.5%] versus 19.7% [95% CI: 7.4-42.7%]) and lower mortality (42.1% [95% CI: 35.9-48.6%] versus 52.8% [95% CI: 33.3-71.5%]) compared to MEDT patients, but neither result was statistically significant. EVT patients were more likely to develop sICH (OR=10.36; 95% CI: 3.92-27.40). Conclusions: EVT treatment of PC-LVO trended toward superior functional outcomes and reduced mortality compared to MEDT despite a trend toward increased sICH in EVT patients. Existing randomized and prospective studies are insufficiently powered to demonstrate a benefit of EVT over MEDT in PC-LVO patients.

Posterior Circulation Endovascular Thrombectomy for Large Vessels Occlusion in Patients Presenting with NIHSS Score ≤ 10.

Mechanical thrombectomy (MT) is currently the gold standard treatment for ischemic stroke due to large vessel occlusion (LVO). However, the evidence of clinical usefulness of MT in posterior circulation LVO (pc-LVO) is still doubtful compared to the anterior circulation, especially in patients with mild neurological symptoms. The database of 10 high-volume stroke centers in Europe, including a period of three year and a half, was screened for patients with an acute basilar artery occlusion or a single dominant vertebral artery occlusion (“functional” BAO) presenting with a NIHSS ≤10, and with at least 3 months follow-up. A total of 63 patients were included. Multivariate analysis demonstrated that female gender (adjusted OR 0.04; 95% CI 0–0.84; p = 0.04) and combined technique (adj OR 0.001; 95% CI 0–0.81; p = 0.04) were predictors of worse outcome. Higher pc-ASPECTS (adj OR 4.75; 95% CI 1.33–16.94; p = 0.02) and higher Delta NIHSS (adj OR 2.06; 95% CI 1.16–3.65; p = 0.01) were predictors of better outcome. Delta NIHSS was the main predictor of good outcome at 90 days in patients with posterior circulation LVO presenting with NIHSS score ≤ 10.

Mechanical Thrombectomy for Anterior versus Posterior Circulation Large Vessel Occlusion Stroke with Emphasis on Posterior Circulation Outcomes

Although there is class I evidence for mechanical thrombectomy (MT) for anterior circulation large vessel occlusion (LVO) stroke, no high-class evidence exists for the posterior circulation. Here, we sought to compare clinical features of anterior versus posterior LVO as well as predictors of a posterior LVO MT outcome. Patients with acute ischemic stroke who underwent MT for anterior and posterior LVO stroke between February 2016 and August 2020 from 2 comprehensive stroke centers were reviewed. Anterior and posterior LVO strokes were compared. In addition, predictors for a favorable outcome (modified Rankin scale [mRS] 0-3), death (mRS 6), and futile revascularization (mRS 4-6 despite TICI 2b/3 revascularization) for posterior LVO were analyzed. Collectively, 813 LVO thrombectomy cases were analyzed, and 77 of 813 cases (9.5%) were located in the posterior circulation. Although favorable 90-day functional outcome rates did not differ between anterior and posterior LVO (P= 0.093), death was significantly more frequent among posterior LVO cases (P= 0.013). In the posterior LVO subgroup, a primary aspiration technique and successful revascularization TICI 2b/3 irrespective of time to the intervention were independently associated with achieving a favorable outcome. Primary aspiration was identified to inversely associate with futile revascularization. Anterior and posterior circulation MT patients have distinct clinical profiles. The use of primary aspiration appears fundamental for beneficial outcomes in posterior circulation MT.

Posterior Circulation Endovascular Thrombectomy for Large-Vessel Occlusion: Predictors of Favorable Clinical Outcome and Analysis of First-Pass Effect.

Successful vessel recanalization in posterior circulation large-vessel occlusion is considered crucial, though the evidence of clinical usefulness, compared with the anterior circulation, is not still determined. The aim of this study was to evaluate predictors of favorable clinical outcome and to analyze the effect of first-pass thrombectomy. A retrospective, multicenter, observational study was conducted in 10 high-volume stroke centers in Europe, including the period from January 2016 to July 2019. Only patients with an acute basilar artery occlusion or a single, dominant vertebral artery occlusion ("functional" basilar artery occlusion) who had a 3-month mRS were included. Clinical, procedural, and radiologic data were evaluated, and the association between these parameters and both the functional outcome and the first-pass effect was assessed. A total of 191 patients were included. A lower baseline NIHSS score (adjusted OR, 0.77; 95% CI, 0.61-0.96; P = .025) and higher baseline MR imaging posterior circulation ASPECTS (adjusted OR, 3.01; 95% CI, 1.03-8.76; P = .043) were predictors of better outcomes. The use of large-bore catheters (adjusted OR, 2.25; 95% CI, 1.08-4.67; P = .030) was a positive predictor of successful reperfusion at first-pass, while the use of a combined technique was a negative predictor (adjusted OR, 0.26; 95% CI, 0.09-0.76; P = .014). The analysis of our retrospective series demonstrates that a lower baseline NIHSS score and a higher MR imaging posterior circulation ASPECTS were predictors of good clinical outcome. The use of large-bore catheters was a positive predictor of first-pass modified TICI 2b/3; the use of a combined technique was a negative predictor.

Abstract P486: Mechanical Embolectomy Using a Novel Telescopic System Featuring a Specialized Delivery and 0.088” Aspiration Catheter for the Treatment of Acute Ischemic Stroke: Preliminary Results of the SUMMIT NZ Trial

Background: The treatment approach of aspiration rather than use of a stent retriever as first-line therapy is increasingly regarded as standard of care for acute ischemic stroke. Continued technological advances include the ongoing development of aspiration embolectomy catheters that are larger in bore, guided by delivery catheters that are more maneuverable through the tortuous neurovasculature. Methods: SUMMIT NZ (ACTRN12619000890134p) was designed as a prospective, single-arm, open label clinical trial at two sites in New Zealand. Eligible participants were patients presenting with acute ischemic stroke from either anterior or posterior circulation large-vessel occlusion within 24 hours of onset, a National Institutes of Health Stroke Scale Score ≥ 6 and a pre-stroke modified Rankin Score of ≤ 2. A novel tapered tip delivery catheter was specifically designed to deliver 0.070” and 0.088” aspiration catheters telescoped through a specialized 8F 90 cm introducer sheath (Route 92 Medical, Inc. San Mateo, CA). The primary effectiveness endpoint was arterial revascularization as measured by a modified Thrombosis in Cerebrovascular Infarction (mTICI) score of 2b or greater at the end of angiography after all endovascular treatments as adjudicated by an independent core laboratory. The primary safety endpoints were device-related peri-procedural complications such as dissection or perforation, symptomatic Intracranial Cerebral Hemorrhage (SICH) at 24 hours and embolization to a previously uninvolved territory. Results: From September 27, 2019 to June 23, 2020, 18 subjects (mean age 69.5, NIHSSS 15.2, time last known well 6.2 hours) were enrolled with a diagnosis of acute ischemic stroke. Acute occlusion was located in the middle cerebral artery (78%, 14/18) and internal carotid artery (22%, 4/18). Successful revascularization was achieved in 94% (17/18) of subjects. No serious adverse device effects have been reported. Conclusions: Preliminary findings suggest that aspiration first mechanical embolectomy using a novel telescoping system including an 0.088” inner diameter aspiration catheter achieves a high rate of arterial revascularization with an acceptable safety profile. A full report on enrollment and results are to be presented.

Current Status of Endovascular Treatment for Acute Large Vessel Occlusion in China: A Real-World Nationwide Registry.

The benefit of endovascular treatment (EVT) for large vessel occlusion in clinical practice in developing countries like China needs to be confirmed. The aim of the study was to determine whether the benefit of EVT for acute ischemic stroke in randomized trials could be generalized to clinical practice in Chinese population. We conducted a prospective registry of EVT at 111 centers in China. Patients with acute ischemic stroke caused by imaging-confirmed intracranial large vessel occlusion and receiving EVT were included. The primary outcome was functional independence at 90 days defined as a modified Rankin Scale score of 0 to 2. Outcomes of specific subgroups in the anterior circulation were reported and logistic regression was performed to predict the primary outcome. Among the 1793 enrolled patients, 1396 (77.9%) had anterior circulation large vessel occlusion (median age, 66 [56-73] years) and 397 (22.1%) had posterior circulation large vessel occlusion (median age, 64 [55-72] years). Functional independence at 90 days was reached in 45% and 44% in anterior and posterior circulation groups, respectively. For anterior circulation population, underlying intracranial atherosclerotic disease was identified in 29% of patients, with higher functional independence at 90 days (52% versus 44%; P=0.0122) than patients without intracranial atherosclerotic disease. In the anterior circulation population, after adjusting for baseline characteristics, procedure details, and early outcomes, the independent predictors for functional independence at 90 days were age <66 years (odds ratio [OR], 1.733 [95% CI, 1.213-2.476]), time from onset to puncture >6 hours (OR, 1.536 [95% CI, 1.065-2.216]), local anesthesia (OR, 2.194 [95% CI, 1.325-3.633]), final modified Thrombolysis in Cerebral Infarction 2b/3 (OR, 2.052 [95% CI, 1.085-3.878]), puncture-to-reperfusion time ≤1.5 hours (OR, 1.628 [95% CI, 1.098-2.413]), and National Institutes of Health Stroke Scale score 24 hours after the procedure <11 (OR, 9.126 [95% CI, 6.222-13.385]). Despite distinct characteristics in the Chinese population, favorable outcome of EVT can be achieved in clinical practice in China. Registration: URL: https://www.clinicaltrials.gov; Unique identifier: NCT03370939.

Initial Reliability and Validity testing of the DESTINY Stroke and Large Vessel Screening Tool

Background: Screening is a valuable tool in emergency medicine for triaging, activation of protocols, and resource allocation. The Dallas Emergency Department Screening Tool to Identify Stroke (DESTINY) was developed to screen for all stroke subtypes, with improved sensitivity for posterior circulation stroke and large vessel occlusion (LVO). The main purpose of this study was to evaluate how reliably the tool could be taught and used by ED Nurses.&#x0D; Methods: This is Phase 1 of a multi-phase study to evaluate the DESTINY tool. A vascular neurologist retrospectively reviewed 409 stroke code activations between January and December of 2018. Thirty descriptive vignettes were composed: right anterior circulation stroke (n=5), left anterior circulation stroke (n=5), posterior circulation stroke (n=5), TIA and stroke mimic (n=6), non-LVO stroke (n=5), and hemorrhagic stroke (n= 4). Fifteen emergency medicine registered nurses used the DESTINY tool to screen the vignettes following the stroke education and DESTINY training module.&#x0D; Results: Individual Pearson Correlation Coefficients (PCC) were calculated for each nurse compared to the vascular neurologist (range: 0.43860 to 0.96966; mean: 0.8746 ± 0.1484). All individual PCC were statistically significant except for one [PCC of 0.43860 (p = 0.0153)]. Cronbach’s Alpha scores were very similar across multiple raters (standardized alpha for nurse raters: 0.9853). Omnibus test to compare DESTINY scores by stroke type demonstrated left anterior LVO and mimic/TIA stroke had few outlier observations, however, poorly differentiated hemorrhagic from ischemic stroke&#x0D; Conclusion: As demonstrated by high interrater reliability, the DESTINY tool can be effectively taught to ED nurses using clinical vignettes. The DESTINY tool is good at differentiating non-LVO, anterior LVO, mimics, and TIAs; while the ability to distinguish between anterior LVO/posterior LVO and ischemic/hemorrhagic stroke was sub-optimal. Utilizing the lessons learned in the early version of the DESTINY screening tool we expect that the high-reliability scores will continue to improve in future prospective studies.

Impact of general anesthesia on posterior circulation large vessel occlusions after endovascular thrombectomy.

The impact of general anesthesia on functional outcome in patients with large vessel occlusion remains unclear. Most studies have focused on anterior circulation large vessel occlusion; however, little is known about the effect of general anesthesia in patients with posterior circulation-large vessel occlusion. We performed a retrospective analysis from the prospective CICAT registry. All patients with posterior circulation-large vessel occlusion-and undergoing endovascular therapy between January 2016 and January 2020 were included. Demographics, baseline characteristics, procedural data, and anesthesia modality (general anesthesia or conscious sedation) were evaluated. The primary outcome was the proportion of patients with good clinical outcome (modified Rankin Scale score of 0-2) at three months. 298 patients underwent endovascular treatment with posterior circulation-large vessel occlusion-were included. Age, diabetes mellitus, renal insufficiency, baseline National Institutes of Health Stroke Scale score, puncture to recanalization length, ≥3 device passes, absent of successful recanalization (defined as treatment in cerebral ischemia of 3), and general anesthesia were statistically associated with poor outcome (mRS: 3-6). In the multivariable regression, general anesthesia and ≥3 device passes were independently associated with poor outcome (aOR: 3.11, (95% CI: 1.34-7.2); P = 0.01 and 3.77, (95% CI: 1.29-11.01); P = 0.02, respectively). Patients treated with general anesthesia were less likely to have a good outcome at three months compared to conscious sedation (19.7% vs. 45.1%, P < 0.001). In our study population, general anesthesia use is associated with poor clinical outcome in patients with posterior circulation-large vessel occlusion-treated endovascularly.

Sex-Related Differences after Endovascular Treatment of Acute Ischemic Stroke in the ‘Real World’

BackgroundGender differences are often reported in the field of ischemic stroke, although most of such discrepancies were observed in randomized trials involving highly selected populations. We therefore explored gender differences regarding 90-day outcomes in large vessel occlusion (LVO) strokes receiving endovascular treatment in a real world setting. MethodsThis prospective registry included anterior and/or posterior circulation LVO strokes admitted between January 2014 and December 2019 who received mechanical thrombectomy up to 24 hours from symptoms onset or last known to be well. We explored sex-related differences in rates of functional independence (modified Rankin Scale, mRS, ≤2) at 90 days. Secondary outcomes included “National Institutes of Health Stroke Scale” (NIHSS) at 24 hours, successful reperfusion defined as modified Thrombolysis in Cerebral Infarction (mTICI) scale 2b/3, death, and symptomatic intracranial hemorrhage (sICH). ResultsA total of 288 LVO stroke patients comprised the study population, involving 148 (51.4%) women. Females were older (71.4±15.7 vs. 66.1±14.0 years, p=0.003) and had lower rates of coronary artery disease (15% vs. 24%, p=0.05). The median time from symptoms onset to hospital arrival was 315 min (IQR 139.5-495.0) in females and 255.0 (IQR 117.0-405.0) in males (p=0.052). Rates of mRS ≤2 at 90 days were comparable (females 46% vs. males 49%, p=0.50). Successful reperfusion was achieved in 82% of females and 89% of males (p=0.10). Rates of sICH (females 10% vs. males 13%, p=0.47) and death (females 18% vs. males 21%, p=0.50) at 90 days were similar. NIHSS at 24 hours was the strongest predictor of functional independence at 90 days (area under ROC curve 0.92 (95%CI 0.87; 0.95)]. ConclusionsOur prospective registry involving a real world setting suggests that females are equally likely to achieve good outcomes after endovascular treatment despite being older and having delayed hospital arrival compared to males. In addition, we found that NIHSS at 24 hours was the strongest predictor of functional independence at 90 days, sICH, and death.

Mechanical thrombectomy in isolated large vessel posterior cerebral artery occlusions.

Mechanical thrombectomy (MT) in posterior circulation large vessel occlusion (LVO), including posterior cerebral artery (PCA), has not been validated since all five major MT trials excluded such patients. To evaluate the feasibility and preliminary safety and efficacy of MT in isolated PCA occlusion stroke patients with new-generation MT devices. Endovascularly treated acute ischemic stroke (AIS) patients were identified from a prospectively collected database and their baseline characteristics were noted. Clinical outcomes were angiographic recanalization, a favorable clinical outcome at 3months on modified Rankin Scale (mRS) and visual field (VF) deficit improvement on confrontation test, rate of intracranial hemorrhage (ICH), and mortality at 3months. A total of 355 AIS patients underwent MT from January 2018 to December 2019. Isolated PCA MT was performed in 15 consecutive patients. The mean age was 64 ± 17years, and 9(60%) were women. Median presentation NIHSS was 9 (interquartile range 5-15). MT devices used were stent retrievers in 6 patients and combined aspiration and stent retriever in 9 patients. Complete revascularization (TICI 2c or 3) was achieved in 12/15 patients. 3-month VF normalization was seen in 7/12 of the patients. Post-procedure symptomatic ICH occurred in 1/15 of patients. mRS score of 0-2 was achieved in 9/15 of patients but one patient was dead at 3months post procedure. MT is feasible and can achieve successful reperfusion in isolated PCA occlusions and resulted in favorable motor and visual outcomes in this small series of ischemic stroke patients.

Significant aortic stenosis associated with poorer functional outcomes in patients with acute ischaemic stroke undergoing endovascular therapy

Bi-directional feedback mechanisms exist between the heart and brain, which have been implicated in heart failure. We postulate that aortic stenosis may alter cerebral haemodynamics and influence functional outcomes after endovascular thrombectomy for acute ischaemic stroke. We compared clinical characteristics, echocardiographic profile and outcomes in patients with or without aortic stenosis that underwent endovascular thrombectomy for large vessel occlusion acute ischaemic stroke. Consecutive acute ischaemic stroke patients with anterior and posterior circulation large vessel occlusion (internal carotid artery, middle cerebral artery and basilar artery) who underwent endovascular thrombectomy were studied. Patients were divided into those with significant aortic stenosis (aortic valve area <1.5 cm2) and without. Univariate and multivariate analyses were employed to compare and determine predictors of functional outcomes measured by modified Rankin scale at three months. We identified 26 (8.5%) patients with significant aortic stenosis. These patients were older (median age 76 (interquartile range 68-84) vs. 67 (interquartile range 56-75) years, p = 0.001), but similar in terms of medical comorbidities and echocardiographic profile. Rates of successful recanalisation (73.1% vs. 78.0%), symptomatic intracranial haemorrhage (7.7% and 7.9%) and mortality (11.5% vs. 12.6%) were similar. Significant aortic stenosis was independently associated with poorer functional outcome (modified Rankin scale >2) at three months (adjusted odds ratio 2.7, 95% confidence interval 1.1-7.5, p = 0.048), after adjusting for age, door-to-puncture times, stroke severity and rates of successful recanalisation. In acute ischaemic stroke patients managed with endovascular thrombectomy, significant aortic stenosis is associated with poor functional outcome despite comparable recanalisation rates. Larger cohort studies are needed to explore this relationship further.

Emergency Intracranial Stenting in Acute Stroke: Predictors for Poor Outcome and for Complications.

BackgroundStent‐retriever thrombectomy is the first‐line therapy in acute stroke with intracranial large vessel occlusion. In case of failure of stent‐retriever thrombectomy, rescue stent angioplasty might be the only treatment option to achieve permanent recanalization. This study aims at identifying predictors for poor outcome and complications in a large, multicenter cohort receiving rescue stent angioplasty.Methods and ResultsWe performed a retrospective analysis of patients with large vessel occlusion who were treated with rescue stent angioplasty after stent‐retriever thrombectomy between 2012 and 2018 in 7 neurovascular centers. We defined 2 binary outcomes: (1) functional clinical outcome (good modified Rankin Scale, 0–2; and poor modified Rankin Scale, 4–6) and (2) early symptomatic intracerebral hemorrhage. Impacts of clinical, radiological, and interventional parameters on outcomewere assessed in uni‐ and multivariable logistic regression models. Two hundred ten patients were included with target vessels located within the anterior circulation (136 of 210; 64.8%) and posterior circulation (74 of 210; 35.2%). Symptomatic intracerebral hemorrhage occured in 22 patients, 86.4% (19 of 22) after anterior and 13.6% (3 of 22) after posterior circulation large vessel occlusion. Good functional outcome was observed in 44.8% (73 of 163). A higher National Institutes of Health Stroke Scale on admission (adjusted odds ratio, 1.10; P=0.002), a higher premorbid modified Rankin Scale (adjusted odds ratio, 2.02; P=0.049), and a modified Thrombolysis in Cerebral Infarction score of 0 to 2a after stenting (adjusted odds ratio, 23.24; P<0.001) were independent predictors of poor functional outcome.ConclusionsUse of rescue stent angioplasty can be considered for acute intracranial large vessel occlusion in cases after unsuccessful stent‐retriever thrombectomy. Likelihood of symptomatic intracerebral hemorrhage is higher in anterior circulation stroke.

Vertebrobasilar Artery Calcification and Outcomes in Posterior Circulation Large Vessel Occlusion Thrombectomy.

Background and Purpose- Intracranial carotid artery calcification is associated with worse outcome in anterior circulation stroke patients who undergo endovascular thrombectomy. We investigated the association between vertebrobasilar artery calcification (VBAC) and outcome in patients undergoing endovascular thrombectomy for posterior circulation large vessel occlusion. Methods- Consecutive patients treated for posterior circulation large vessel occlusion from a prospective single-center registry were studied. VBAC was manually segmented on computed tomography brain scans. The associations between VBAC and VBAC volume, functional independence (90-day modified Rankin Scale score of 0-2), and 90-day mortality were assessed using propensity score-adjusted logistic regression. Results- Sixty-four posterior circulation large vessel occlusion patients were included. Twenty-five (39.1%) patients had VBAC, and of these, the median (interquartile range) VBAC volume was 19.8 (6.65-23.4) mm3. VBAC was associated with reduced functional independence (OR, 0.19 [95% CI, 0.04-0.78]; P=0.03) and increased mortality (OR, 9.44 [95% CI, 2.43-36.62]; P=0.005). Larger VBAC volumes were a significant predictor of reduced functional independence and increased mortality. Conclusions- VBAC is an independent predictor of outcome in patients undergoing endovascular thrombectomy for posterior circulation large vessel occlusion. Considering the presence of VBAC might improve prognostication and shared treatment decision-making between patients, families, and physicians.

Abstract WP70: Reperfusion Therapy in Posterior Circulation Large Vessel Occlusion With Perfusion Deficits May Be Safe and Improve Outcomes Beyond 4.5 Hours

Introduction: Whether reperfusion therapy is safe and efficacious in acute ischemic strokes (AIS) due to posterior circulation large vessel occlusions (PCLVO) beyond 4.5 hrs is unknown. Methods: A retrospective analysis of AIS due to PCLVO presenting to a comprehensive stroke center up to 24 hrs from last known well. Patients were stratified based on the treatment received into reperfusion therapy (IV-tPA and/or endovascular thrombectomy) and no reperfusion therapy. All patients received CT/CTA and CT perfusion with RAPID mismatch determination. Functional independence (90 day mRS 0-2) and sICH were primary and secondary outcomes. The two groups were compared in the overall cohort in an ordinal logistic regression and in a propensity matched analyses. Results: Between 8/2017 and 5/2019, 52 patients were included [reperfusion = 23(44%) vs no-reperfusion=29(56%)]. Reperfusion rate beyond 4.5 hours was 26% (6/23). The two groups were similar at baseline except for larger perfusion delays (Tmax&gt;6s) volume [median (IQR), 16 (0, 46) vs. 0 (0, 25) cc, p=0.03], and higher presentation NIHSS [median (IQR), 10 (5, 21) vs. 4 (1, 8), p=0.004] in the reperfusion group. Reperfusion was associated with higher functional independence rates 10 (43%) vs. 8 (28%), p=0.23 (fig 1), and a trend for a shift towards better outcomes adj cOR 1.89, 95% CI=0.59-6.13, p=0.29. There was no difference in sICH rates 9% vs. 0%, P=0.19. In a propensity matched analysis on NIHSS and perfusion deficit of 14 pairs, reperfusion was associated with statistically significant higher mRS 0-2 rates 9 (64%) vs. 1 (7%), p=0.004 (fig 2). Functional independence rates did not differ in the reperfusion group in relation to time (47% &lt;4.5 hrs vs. 33%≥4.5 hrs), p=0.36 for heterogeneity. Conclusion: PCLVOs with more severe strokes and large perfusion deficits were more likely to receive reperfusion which was associated with a shift towards better outcomes both earlier and beyond 4.5 hours without worsening safety outcomes.

Abstract WP19: Reliability of CT Perfusion in the Posterior Circulation in Comparison to the Anterior Circulation

Background: DAWN and DEFUSE-3 excluded posterior-circulation cases, but in practice endovascular therapy (EVT) is common due to life-threatening large-vessel occlusions. Often CT perfusion (CTP) is acquired to aid in the decision-making of these cases, but the reliability of using CT perfusion in the posterior-circulation is unknown Hypothesis: Given the differences in hemodynamics (~20% of total CBF to the basilar, reduced mean velocity, and differences in collateral supply) penumbra estimates using RAPID software will be less accurate in predicting the final infarct volume on DWI. Methods: In patients who did not receive any treatment (tPA or EVT), the Tmax &gt;6s, as operationally defined as penumbra, should approximate the infarct on DWI. As such, only posterior circulation patients without EVT or tPA were included. Anterior circulation patients were matched on demographics, medical history, outcomes. A ratio of Tmax/DWI was calculated to assess how closely perfusion approximated final infarct folume. Nonparametric correlation with Kendall’s tau-b was also performed. Results: Eleven patients with a posterior circulation large-vessel occlusion (pc-LVO) were compared to 30-matched patients with anterior circulation (ac-LVO). Age was 62.4±16 for ac-LVO vs. 64.5±13 for pc-LVO. Significant differences were seen in sex with ac-LVO 82% male, and pc-LVO 46% male (t=-2.06 p=0.046). Pc-LVO also had more subjects with an unknown last known well. Mean admission NIHSS was 15.6±8 ac-LVO, and 16.4±10 in pc-LVO group was similar. Mean discharge NIHSS was 12.6±9 ac-LVO vs 12.4±10 pc-LVO. NO signficicant difference in 30d mRS, 24h NIHSS, or mortality within 90d. As excpected in the anterior circulation cases final infarct volume correlated with Tmax&gt;6s Kendall’s tau-b=0.57 (p=0.000013), and Tmax&gt;8s (tau-b=0.55), Tmax&gt;10s (tau-b=0.55. Whereas, In the posterior circulation Tmax&gt;6s (tau-b=0.41, N.S.), but Tmax&gt;8s (tau-b=0.64, p=0.007) and Tmax&gt;10(tau-b=0.69, p=0.005). Seen another way the ratio of Tmax&gt;6s:DWI = 2.47 (ac-LVO) vs 5.84 (pc-LVO) (t=-1.22, p=0.004, but Tmax&gt;8s 1.57 vs 1.50 (t=0.11, p=9.12). Conclusion: Final infarct volume was not significantly associated with Tmax&gt;6s in posterior circulation cases. Instead Tmax&gt;8s is more reliable.

HbA1c and clinical outcomes after endovascular treatment in patients with posterior circulation large vessel occlusion: a subgroup analysis of a nationwide registry (BASILAR).

Background and aims:Recently, several clinical trials have shown that increased glycated hemoglobin (HbA1c) level is correlated with poor clinical outcomes in ischemic stroke patients after thrombolysis and possibly after mechanical thrombectomy. However, the effect of HbA1c on posterior circulation large vessel occlusion (PCLVO) patients treated with endovascular thrombectomy (EVT) remains unclear. This multicenter study assessed the association between the HbA1c levels and clinical outcomes in patients with PCLVO after EVT.Methods:We studied 385 PCLVO ischemic stroke patients included in the EVT for acute basilar artery occlusion study (BASILAR). Patients were divided into a high HbA1c level group (HbA1c >6.5%) and a low HbA1c level group (HbA1c ⩽6.5%). The efficacy outcome was a 90-day favorable functional outcome (modified Rankin Scale 0–3). The safety outcomes included symptomatic intracerebral hemorrhage and mortality at 90 days after EVT.Results:The frequency of a favorable outcome in patients with an HbA1c ⩽6.5% was significantly higher than that in the HbA1c >6.5% group (41.2% versus 26.2%, p = 0.001). In multivariate analysis with adjusted confounders, high HbA1c levels and favorable outcomes were significantly negatively correlated. There was also a significant association between high HbA1c levels and mortality after 3 months. The negative effects of high HbA1c levels on functional status after 3 months were exacerbated in patients aged ⩾65 years.Conclusion:Our multicenter study suggests that a higher serum HbA1c level (HbA1c >6.5%) is an independent predictor of a 90-day poor outcome and mortality in patients with PCLVO after EVT, particularly in those aged ⩾65 years.Clinical Trial Registry identifier: ChiCTR1800014759.

Air retrieval for clot retrieval; time-metrics and outcomes of stroke patients from rural and remote regions air-transported for mechanical thrombectomy at a state stroke unit

BackgroundProviding thrombectomy services to rural or remote regions with small, dispersed populations presents a particular challenge. Sustaining local thrombectomy services is not viable given the low throughput of cases, therefore large vessel occlusion (LVO) stroke patients require emergent transfer, often by air, to the closest high volume urban thrombectomy unit. The aim of this paper is to present logistical, time-metric data and outcome data on LVO stroke patients that have been aeromedically retrieved for thrombectomy from the vast, 2,500,000-km2 rural catchment of the Western Australian state thrombectomy unit. MethodsThe prospectively collected state thrombectomy registry was reviewed and all patients that underwent thrombectomy for LVO strokes following aeromedical retrieval from remote or rural catchments were identified. Multiple logistic and time-metric data points were recorded and outcomes were compared to a cohort of urban patients treated over the same period. ResultsOver a 2-year period 30 patients underwent thrombectomy following aeromedical retrieval, either by helicopter or fixed wing aircraft, from rural and remote regions of Western Australia. The mean aeromedical retrieval distance was 393 km while the maximum retrieval distance was over 2600 km. The mean ictus to recanalization time was 657 min, an mTICI 2b-3 recanalization was achieved in 93% of cases and 62% of anterior circulation, and 50% of posterior circulation LVO stroke patients achieved functional independence at 90-days. Outcome data for rural patients compared favourably to urban patients treated over the same time period. ConclusionWith the availability of an efficient aeromedical retrieval service, LVO stroke patients in rural and remote regions can achieve excellent outcomes following transfer to a high volume thrombectomy unit, even if distances involved are very large.