Field Assessment of Critical Stroke by Emergency Services for Acute Delivery to a Comprehensive Stroke Center: FACE2AD

Patients with acute ischemic stroke (AIS) due to large vessel occlusion (LVO) should be triaged to an endovascular-capable hospital by the emergency medical service (EMS). We designed a prehospital LVO prediction scale based on EMS assessments. In the derivation cohort, 1157 patients transferred to our hospital by the EMS because of suspected stroke within 24 h of onset were retrospectively examined. Factors associated with AIS due to LVO were identified based on the EMS assessment, and a prehospital scale identifying LVO was developed. The accuracy of this scale was validated in 502 consecutive patients who were transferred to 4 stroke centers, and its accuracy was compared with those of 4 previously reported scales. AIS due to LVO was diagnosed in 149 of 1157 patients (13%) in the derivation cohort. One point each was assigned for facial palsy, arm weakness, consciousness impairment (cannot say his/her name), atrial fibrillation, and diastolic blood pressure ≤ 85 mmHg, with two points for conjugate eye deviation (FACE₂AD scale). In the derivation cohort, with the optimal cut-point of FACE₂AD ≥ 3 determined by the area under the curve (AUC; 0.88; 95% confidence interval 0.87-0.90), sensitivity, specificity, positive predictive value, and negative predictive value for FACE₂AD to predict LVO were 0.85, 0.80, 0.39, and 0.97, respectively. In the validation cohort, the FACE₂AD scale had higher accuracy, with an AUC value of 0.84 for predicting LVO compared with the other scales (all p < 0.01). The FACE₂AD scale is a simple, reliable tool for identifying AIS due to LVO by the EMS.

Case-Control Study of Endovascular Thrombectomy in a Canadian Stroke Center

BACKGROUND

Although the efficacy of endovascular thrombectomy (EVT) for acute ischemic stroke caused by intracranial anterior circulation large vessel occlusion (LVO) is proven, demonstration of local effectiveness is critical for health system planning and resource allocation because of the complexity and cost of this treatment.

METHODS

Using our prospective registry, we identified all patients who underwent EVT for out-of-hospital LVO stroke from February 1, 2013 through January 31, 2017 (n = 44), and matched them 1:1 in a hierarchical fashion with control patients not treated with EVT based on age (±5 years), prehospital functional status, stroke syndrome, severity, and thrombolysis administration. Demographics, in-hospital mortality, discharge disposition from acute care, length of hospitalization, and functional status at discharge from acute care and at follow-up were compared between cases and controls.

RESULTS

For EVT-treated patients (median age 66, 50% women), the median onset-to-recanalization interval was 247 min, and successful recanalization was achieved in 30/44 (91%). Alteplase was administered in 75% of cases and 57% of controls (p = 0.07). In-hospital mortality was 11% among the cases and 36% in the control group (p = 0.006); this survival benefit persisted during follow-up (p = 0.014). More EVT patients were discharged home from acute care (50% vs. 18%, p = 0.002). Among survivors, there were nonsignificant trends in favor of EVT for median length of hospitalization (14 vs. 41 days, p = 0.11) and functional independence at follow-up (51% vs. 32%, p = 0.079).

CONCLUSION

EVT improved survival and decreased disability. This demonstration of single-center effectiveness may help facilitate expansion of EVT services in similar health-care jurisdictions.

Large Vessel Occlusion in Acute Ischemic Stroke Patients: A Dual-Center Estimate Based on a Broad Definition of Occlusion Site

BACKGROUND

Accurate assessment of the frequency of large vessel occlusion (LVO) is important to determine needs for neurointerventionists and thrombectomy-capable stroke facilities. Current estimates vary from 13% to 52%, depending on acute ischemic stroke (AIS) definition and methods for AIS and LVO determination. We sought to estimate LVO prevalence among confirmed and suspected AIS patients at 2 comprehensive US stroke centers using a broad occlusion site definition: internal carotid artery (ICA), first and second segments of the middle cerebral artery (MCA M1,M2), the anterior cerebral artery, vertebral artery, basilar artery, or the proximal posterior cerebral artery.

METHODS

We analyzed prospectively maintained stroke databases of patients presenting to the centers between January and December 2017. ICD-10 coding was used to determine the number of patients discharged with an AIS diagnosis. Computed tomography angiography (CTA) or magnetic resonance angiography (MRA) was reviewed to determine LVO presence and site. Percentages of patients with LVO among the confirmed AIS population were reported.

RESULTS

Among 2245 patients with an AIS discharge diagnosis, 418 (18.6%:95% confidence interval [CI] 17.3%-20.0%) had LVO documented on CTA or MRA. Most common occlusion site was M1 (n=139 [33.3%]), followed by M2 (n=114 [27.3%]), ICA (n=69[16.5%]), and tandem ICA-MCA lesions (n=44 [10.5%]). Presentation National Institutes of Health Stroke Scale scores were significantly different for different occlusion sites (P=.02).

CONCLUSIONS

The LVO prevalence in our large series of consecutive AIS patients was 18.6% (95% CI 17.3%-20.0%). Despite the use of a broad definition, this estimate is less than that reported in most previous studies.

Recanalization of Emergent Large Intracranial Vessel Occlusion through Intravenous Thrombolysis: Frequency, Clinical Outcome, and Reperfusion Pattern

BACKGROUND

According to a recent meta-analysis, 1 out of 10 patients with emergent large intracranial vessel occlusion (ELVO) causing stroke have recanalization after intravenous thrombolysis (IVT) alone. However, rate, clinical outcome, and recanalization pattern of this phenomenon are poorly understood.

OBJECTIVES AND METHODS

Patients with ELVO recanalized only by IVT were analyzed, and frequency of recanalization, clinical outcome, safety variables, and reperfusion pattern were assessed. These patients were compared to a group of patients with ELVO who underwent endovascular thrombectomy with or without prior IVT.

RESULTS

Successful or sufficient recanalization after IVT alone occurred in 81 of 760 patients (10.6%) with ELVO who had been referred for endovascular thrombectomy. These 81 patients (group 1) were compared to a group of patients receiving endovascular thrombectomy with prior IVT (group 2) or without (group 3). A good clinical outcome at 90 days was seen in 61.7% of patients in group 1, 32.2% in group 2, and 34.5% in group 3 (p < 0.001). The 3 groups had no significant differences in intracranial hemorrhage. IVT was not independently associated with symptomatic intracranial hemorrhage, parenchymal hematoma, or subarachnoid hemorrhage. Mortality at 90 days was 9.9% in group 1, 20.7% in group 2, and 29.6% in group 3 (p < 0.001). After adjusting for all relevant variables, outcome and mortality differences were nonsignificant. No difference in the rate of successful reperfusion (modified treatment in cerebral ischemia [mTICI] 2b/3) was found. A reperfusion mTICI 3 was achieved in 18.5% in group 1, 60.7% in group 2, and 57.1% in group 3 (p < 0.001). Patients in group 1 had lower chance of achieving a complete recanalization (mTICI 3) compared to patients in group 2, OR 0.15 (95% CI 0.08-0.29) and in group 3, OR 0.17 (95% CI 0.09-0.32; p < 0.001).

CONCLUSIONS

Primary IVT in ELVO caused a recanalization rate of 10.6%, making endovascular treatment either unnecessary or impossible. Early recanalization of ELVO with only IVT is associated with a 61.7% independence rate at 90 days and similar successful reperfusion rates (mTICI2b/3) compared to ELVO treated with endovascular treatment, with or without previous IVT. However, recanalization only through IVT achieves a lower rate of mTICI 3 reperfusion when compared to endovascular treatment.

Diagnostic value of transcranial ultrasonography for selecting subjects with large vessel occlusion: a systematic review

Introduction

A number of pre-hospital clinical assessment tools have been developed to triage subjects with acute stroke due to large vessel occlusion (LVO) to a specialised endovascular centre, but their false negative rates remain high leading to inappropriate and costly emergency transfers. Transcranial ultrasonography may represent a valuable pre-hospital tool for selecting patients with LVO who could benefit from rapid transfer to a dedicated centre.

Methods

Diagnostic accuracy of transcranial ultrasonography in acute stroke was subjected to systematic review. Medline, Embase, PubMed, Scopus, and The Cochrane Library were searched. Published articles reporting diagnostic accuracy of transcranial ultrasonography in comparison to a reference imaging method were selected. Studies reporting estimates of diagnostic accuracy were included in the meta-analysis.

Results

Twenty-seven published articles were selected for the systematic review. Transcranial Doppler findings, such as absent or diminished blood flow signal in a major cerebral artery and asymmetry index ≥ 21% were shown to be suggestive of LVO. It demonstrated sensitivity ranging from 68 to 100% and specificity of 78–99% for detecting acute steno-occlusive lesions. Area under the receiver operating characteristics curve was 0.91. Transcranial ultrasonography can also detect haemorrhagic foci, however, its application is largely restricted by lesion location.

Conclusions

Transcranial ultrasonography might potentially be used for the selection of subjects with acute LVO, to help streamline patient care and allow direct transfer to specialised endovascular centres. It can also assist in detecting haemorrhagic lesions in some cases, however, its applicability here is largely restricted. Additional research should optimize the scanning technique. Further work is required to demonstrate whether this diagnostic approach, possibly combined with clinical assessment, could be used at the pre-hospital stage to justify direct transfer to a regional thrombectomy centre in suitable cases.

Endovascular Treatment of Acute Ischemic Stroke Due to Intracranial Atherosclerotic Large Vessel Occlusion : A Systematic Review

OBJECTIVE

To evaluate the efficacy and safety of endovascular treatment (ET) of acute ischemic stroke (AIS) caused by intracranial atherosclerotic large vessel occlusion (ICAS-LVO).

METHODS

A systemic review and meta-analysis were conducted on studies published between July 2005 and October 2018 on the outcomes of ET in patients with AIS due to ICAS-LVO. The outcomes of the ICAS-LVO and embolic LVO groups were also compared.

RESULTS

A total of 17 studies including 1315 subjects with ICAS-LVO were included. In the single-arm meta-analysis, the pooled estimates of successful recanalization rate, favorable outcomes, symptomatic intracranial hemorrhage and mortality were 88% (95% CI (95% confidence interval), 84-92%), 52% (95% CI, 47-56%), 5% (95% CI, 3-7%) and 15% (95% CI, 12-19%) respectively. The preferred primary treatment was stent-retriever thrombectomy (84.1%) and the preferred rescue treatment was stent implantation with or without percutaneous transluminal angioplasty (PTA, 32.7%). In the double-arm meta-analysis, the incidence of symptomatic intracranial hemorrhage was lower in the ICAS-LVO compared to the embolic-LVO group (OR (odds ratio) = 0.60, 95% CI, 0.46-0.77, p < 0.01), whereas the implementation of rescue treatment (OR = 5.94, 95% CI, 3.15-11.19, p < 0.01) and stenting rate (OR = 10.06, 95%CI, 4.43-22.85, p < 0.01) were higher in the ICAS-LVO group. Other parameters were similar in both groups.

CONCLUSION

The use of ET is a safe and effective therapeutic option for AIS due to ICAS-LVO. Stent-retriever thrombectomy and stent-implement are the preferred primary and rescue therapies respectively for ICAS-LVO. Less symptomatic intracranial hemorrhage and higher stenting were observed in the ICAS-LVO compared to the embolic-LVO group.

Effect of short-term blood pressure variability on functional outcome after intra-arterial treatment in acute stroke patients with large-vessel occlusion

Background

Endovascular treatment (EVT) is advocated for acute ischaemic stroke with large-vessel occlusion (LVO), but perioperative periods are challenging. This study investigated the relationship between post-EVT short-term blood pressure variability (BPV) and early outcomes in LVO patients.

Methods

We retrospectively reviewed 72 LVO patients undergoing EVT between June 2015 and June 2018. Hourly systolic and diastolic blood pressures (SBP and DBP, respectively) were recorded in the first 24 h post-EVT. BPV were evaluated as standard deviation (SD), coefficient of variation (CV), and successive variation (SV) separately for SBP and DBP. Functional independence at 3 months was defined as a modified Rankin Scale (mRS) score of 0–2.

Results

For 58.3% patients with favorable outcomes, the median National Institutes of Health Stroke Scale and Alberta Stroke Program Early CT scores on admission were 14 and 8, respectively. The maximum SBP ([154.3 ± 16.8] vs. [163.5 ± 15.6], P = 0.02), systolic CV ([8. 8% ± 2.0%] vs. [11.0% ± 1.8], P < 0.001), SV ([11.4 ± 2.3] vs. [14.6 ± 2.0], P < 0.001), and SD ([10.5 ± 2.4] vs. [13.8 ± 3.9], P < 0.001) were lower in patients with favorable outcomes. On multivariable logistic regression analysis, systolic SV (OR: 4.273, 95% CI: 1.030 to 17.727, P = 0.045) independently predicted unfavorable prognosis. The area under the curve was 0.868 (95% CI: 0.781 to 0.955, P < 0.001), and sensitivity and specificity were 93.3% and 73.8%, respectively, showing excellent predictive value for 3-month poor-outcomes.

Conclusions

Decreased systolic SV following intra-arterial therapies result in favorable outcomes at 3 months. Systolic SV may be a novel predictor of functional prognosis in LVO patients.

Supplementary information

Supplementary information accompanies this paper at 10.1186/s12883-019-1457-5.

Diagnostic accuracy of clinical tools for assessment of acute stroke: a systematic review

INTRODUCTION

Recanalisation therapy in acute ischaemic stroke is highly time-sensitive, and requires early identification of eligible patients to ensure better outcomes. Thus, a number of clinical assessment tools have been developed and this review examines their diagnostic capabilities.

METHODS

Diagnostic performance of currently available clinical tools for identification of acute ischaemic and haemorrhagic strokes and stroke mimicking conditions was reviewed. A systematic search of the literature published in 2015-2018 was conducted using PubMed, EMBASE, Scopus and The Cochrane Library. Prehospital and in-hospital studies with a minimum sample size of 300 patients reporting diagnostic accuracy were selected.

RESULTS

Twenty-five articles were included. Cortical signs (gaze deviation, aphasia and neglect) were shown to be significant indicators of large vessel occlusion (LVO). Sensitivity values for selecting subjects with LVO ranged from 23 to 99% whereas specificity was 24 to 97%. Clinical tools, such as FAST-ED, NIHSS, and RACE incorporating cortical signs as well as motor dysfunction demonstrated the best diagnostic accuracy. Tools for identification of stroke mimics showed sensitivity varying from 44 to 91%, and specificity of 27 to 98% with the best diagnostic performance demonstrated by FABS (90% sensitivity, 91% specificity). Hypertension and younger age predicted intracerebral haemorrhage whereas history of atrial fibrillation and diabetes were associated with ischaemia. There was a variation in approach used to establish the definitive diagnosis. Blinding of the index test assessment was not specified in about 50% of included studies.

CONCLUSIONS

A wide range of clinical assessment tools for selecting subjects with acute stroke has been developed in recent years. Assessment of both cortical and motor function using RACE, FAST-ED and NIHSS showed the best diagnostic accuracy values for selecting subjects with LVO. There were limited data on clinical tools that can be used to differentiate between acute ischaemia and haemorrhage. Diagnostic accuracy appeared to be modest for distinguishing between acute stroke and stroke mimics with optimal diagnostic performance demonstrated by the FABS tool. Further prehospital research is required to improve the diagnostic utility of clinical assessments with possible application of a two-step clinical assessment or involvement of simple brain imaging, such as transcranial ultrasonography.

[Prehospital management of acute stroke : Using the example of Saarland ambulance services]

BACKGROUND

The preclinical care strategy was changed after reevaluation of endovascular thrombectomy in the S2k guideline of the German Neurological Society (DGN). Severe strokes should be directly transferred to neurovascular centers (model "mothership"). The severity of a stroke should be determined using the LAMS (Los Angeles Motor Scale) score.

MATERIALS AND METHODS

The general conditions of preclinical care of patients with stroke in the Saarland are presented. The key figures and statistical data of clinic assignments in the adapted care strategy are evaluated.

RESULTS

The 2018 data from the Saarland Ambulance Services indicate that 9.1% of all preclinical emergencies are diagnosed with "transient ischemic attack (TIA)/insult/bleeding"; 97.1% of these patients were admitted to one of the 10 hospitals in Saarland with a stroke unit. A care time at the emergency site of 20 min was observed in 78.2%, a prehospital time of 60 min in 90.1% of the missions. Preclinically, severe strokes with LAMS score ≥4 were detected in 19.2% of all stroke patients; 71.6% of these severe strokes were assigned to one of two neurovascular centers in the Saarland.

CONCLUSIONS

With good traffic and hospital infrastructure in Saarland, severe strokes can be treated primarily in neurovascular centers. Differentiated care requirements with monitoring of key figures in medical quality management and clear agreements with the target hospitals in the implementation of a common care strategy are essential.

Understanding the Radial Force of Stroke Thrombectomy Devices to Minimize Vessel Wall Injury: Mechanical Bench Testing of the Radial Force Generated by a Novel Braided Thrombectomy Assist Device Compared to Laser-Cut Stent Retrievers in Simulated MCA Vessel Diameters

Background

Recent reports have raised various concerns about the risk of vessel wall injury while withdrawing current laser-cut stent retrievers during active strut apposition to the vessel walls. The development of braided thrombectomy assist devices in conjunction with aspiration systems may be gentler on the fragile brain vessels and more optimized with regard to the radial force (RF) for vessel diameters of proximal (M1) and distal (M2) large vessel occlusions (LVOs).

Methods

Mechanical bench testing of the RF was performed using a radial compression station mounted on a tensile testing machine. The total RF in newtons (N) generated in vessels with diameters ranging from 2.25 to 3 mm as seen in proximal LVOs (∼M1), and in vessel diameters ranging from 1.5 to 2.24 mm as seen in distal LVOs (∼M2), was measured. The outer diameter of each stent was recorded, and an RF ≤1 N was grouped as "low," while an RF >1 N was grouped as "high" for this analysis.

Results

The total RFs of all laser-cut stent retrievers were all higher in the simulated M2 vessels (>1 N) than in the M1 vessels (<1 N), whereas the total RFs of the braided thrombectomy assist devices were uniformly low in both the simulated M1 and the simulated M2 vessels.

Conclusions

Novel braided thrombectomy assist devices in conjunction with aspiration systems have lower RFs than existing laser-cut stent retrievers in M1 and M2 vessel diameters. Further in vivo studies are needed to delineate the impact of lowering the RF on vessel wall integrity.

Thrombectomy for a Patient with Concomitant Acute Cervical Internal Carotid and Middle Cerebral Artery Occlusion: Video Case

We present the case of a 62-yr-old female who presented with ground-level fall and new onset of left-sided weakness of 30 min duration. CT angiogram revealed right ICA pseudo-occlusion and thrombus filling the right proximal M1 segment of the right MCA. On detailed neurological exam patient was noted to have NIHSS of 25. Patient was started on IV TPA infusion and was taken to interventional angiography suite after an informed consent was obtained. Diagnostic angiography was performed which demonstrated critical stenosis of the right proximal internal carotid artery. Right carotid artery stenting and balloon angioplasty of the carotid stent with distal embolic protection device was performed. Post carotid stent angiogram once again confirmed proximal right M1 pseudo-occlusion in the right MCA distribution. The clot was removed using a stent retriever, thus achieving complete recanalization (TICI 3) of the right cerebral hemisphere. The patient returned to baseline neurological status and a 1 mo follow-up diagnostic angiogram revealed patent carotid stent. Following the case presentation, we present the nuances of acute ischemic stroke management of large vessel occlusion with an emphasis on technical nuances, recent published guidelines1 and the literature.2-8.

Proteomic profiling of plasma biomarkers in acute ischemic stroke due to large vessel occlusion

Background

Acute ischemic stroke (AIS) due to large vessel occlusion (LVO) is a devastating cerebrovascular disorder, which could benefit from collateral circulation. Proteins associated with acute LVO pathogenesis and endothelial function may appear in blood samples of AIS patients due to LVO, thus permitting development of blood-based biomarkers for its diagnosis and prognosis.

Methods

This study is a single-center, retrospective, observational case–control trial. Consecutive patients who presented at the Department of Neurology of Tongji Hospital were recruited from July 2016 to April 2018. In the discovery phase, a proteomic approach with iTRAQ-based LC–MS/MS was used to investigate the altered proteomic pattern in plasma from patients with AIS due to LVO. In the validation study, Western blots was used to identify biomarkers associated with stroke diagnosis as well as their prognostic value associated with different collateral statuses.

Results

For this exploratory study, the proteomic analysis of plasma from 40 patients with AIS due to LVO and 20 healthy controls revealed seven differentially expressed proteins with a 1.2/0.83-fold or greater difference between groups. The four elevated proteins, PPBP (1.58 ± 0.78 vs 0.98 ± 0.37; P < 0.001), THBS1 (1.13 ± 0.88 vs 0.43 ± 0.26; P < 0.001), LYVE1 (1.61 ± 0.55 vs 0.97 ± 0.50; P < 0.001), and IGF2 (1.19 ± 0.42 vs 0.86 ± 0.24; P < 0.001), were verified by Western blots analysis in an independent cohort including 33 patients and 33 controls. A strong interaction was observed between the four-protein panel and the diagnosis of AIS due to LVO (AUC 0.947; P < 0.001). Furthermore, IGF2, LYVE1, and THBS1 were closely associated with collateral status (IGF2 0.115, 95% CI 0.016–0.841, P = 0.033; LYVE1 0.183, 95% CI 0.036–0.918, P = 0.039; THBS1 4.257, 95% CI 1.273–14.228, P = 0.019), and proved to be independent predictors of good outcome (IGF2 0.115, 95% CI 0.015–0.866, P = 0.036; LYVE1 0.028, 95% CI 0.002–0.334, P = 0.005; THBS1 3.294, 95% CI 1.158–9.372, P = 0.025) at a 3-month follow-up.

Conclusions

The identified 4-biomarker panel could provide diagnostic aid to the existing imaging modalities for AIS due to LVO, and the prognostic value of IGF2, LYVE1, and THBS1 was proved in predicting functional outcomes related to collateral status.

Trial registration ClinicalTrials.gov NCT 03122002. Retrospectively registered April 20, 2017. URL of trial registry record: https://www.clinicaltrials.gov/ct2/show/NCT03122002?term=NCT+03122002&rank=1

Electronic supplementary material

The online version of this article (10.1186/s12967-019-1962-8) contains supplementary material, which is available to authorized users.

Acute Left M1 Stroke With Critical Left Internal Carotid Artery Stenosis: Video Case

We present the case of a 68-yr-old woman who presented with an acute left middle cerebral artery syndrome. Noninvasive angiography obtained 13 h after last known well time demonstrated both left M1-segment middle cerebral artery (MCA) occlusion and near-complete occlusion of the left internal carotid artery (ICA) just distal to the carotid bifurcation. Intervention was offered given the sizeable mismatch demonstrated by computed tomography (CT) perfusion imaging. After administering loading doses of aspirin and clopidogrel, we initially performed carotid angioplasty and stenting to open the internal carotid artery, which was otherwise impassible. Subsequently, thrombectomy of the M1 occlusion was performed with direct aspiration. Postprocedural imaging demonstrated preservation of the at-risk brain parenchyma. The patient demonstrated significant improvement in strength and speech after the procedure, and she was discharged to an inpatient rehabilitation center for further treatment. The patient and her family gave consent for this report.

Intravenous Tissue Plasminogen Activator for Large Vessel Ischemic Stroke - Is There Still a Role?

While the efficacy of Intravenous tissue plasminogen activator (tPA) is well established, its impact on large vessel occlusion (LVO) is controversial. Whether IV tPA should be bypassed in favor of endovascular thrombectomy (MT) will be addressed. Compelling evidence exists to suggest tPA administration might be bypassed in tPA eligible patients in favor of MT for LVO. A trial of MT with patients randomized for IV tPA within the 4.5-h time window should conducted at comprehensive stroke centers demonstrating equipoise between time to tPA or MT with time to treatment from ED arrival of 45 min. We may do well to consider the systems pathway taken by interventional cardiologists 15 years ago.

Longer 6-mm Diameter Stent Retrievers Are Effective for Achieving Higher First Pass Success with Fibrin-Rich Clots

First pass success (FPS) can be defined as in vitro retrieval of clot in a single pass during mechanical thrombectomy (MT) for acute large vessel occlusion (LVO). Despite advancements in MT technology, retrieval of fibrin-rich clots remains a challenge. Therefore, the effect of stent retriever length on FPS for fibrin-rich clots was investigated by using Solitaire^TM 6 × 40 versus 6 × 30 mm devices with a balloon guide catheter (BGC) or distal access catheter (DAC) and sheath, in an in vitro model of anterior circulation neurovascular anatomy. Additionally, vascular safety of the Solitaire^TM 6 × 40 versus 6 × 30 mm devices was evaluated in a porcine model for differences in: luminal thrombus, inflammation, endothelial coverage, fibrin deposits, smooth muscle cell loss, elastic lamina and adventitia disruption, intimal hyperplasia, and lumen reduction, at 0, 30, and 90 days post-treatment. In vitro overall FPS was measured as: Solitaire^TM 6 × 40 (95%) and Solitaire^TM 6 × 30 (67%). FPS for clot location in middle cerebral artery was: (a) BGC (6 × 40 mm: 100%; 6 × 30 mm: 100%; n = 8); (b) DAC with 088 sheath (6 × 40 mm: 83%; 6 × 30 mm: 33%; n = 12). FPS for clot location in internal carotid artery was: (a) BGC (6 × 40 mm: 100%; 6 × 30 mm: 80%; n = 11); (b) DAC with 088 sheath (6 × 40 mm: 100%; 6 × 30 mm: 67%; n = 10). Stent length had a significant effect (Fisher's exact test; p < 0.05) on FPS. In vivo evaluation in the porcine model showed no difference in vascular safety parameters between the Solitaire^TM 6 × 40 and 6 × 30 mm devices (p > 0.05) at all time points in the study. Longer stent retrievers may be safe and effective in improving FPS for fibrin-rich clots in in vitro and in vivo models of LVO.

Multicenter Volumetric Assessment of Artifactual Hypoperfusion Patterns using Automated CT Perfusion Imaging

BACKGROUND AND PURPOSE

Automated computed tomography perfusion (CTP) is recommended to inform selection of stroke patients for thrombectomy >6 hours from last known normal (LKN). However, artifacts on automated perfusion output may overestimate the tissue at risk leading to misclassification of thrombectomy eligibility in some patients.

METHODS

We conducted a retrospective multisite study of consecutive patients with anterior large vessel occlusion (LVO) undergoing CTP (6/2017-12/2017). The primary outcome was the RAPID automated T_max  > 6 seconds volume that was discordant with clinical symptoms and vessel imaging, manually assessed by two independent readers. The discordant penumbral volume was compared to the automated output and corrected mismatch ratios were generated.

RESULTS

Of 410 consecutive patients who underwent CTP for suspected stroke, 60 (15%) had acute anterior circulation LVO. Of these, 26 (43%) had T_max > 6 seconds abnormalities discordant with clinical symptoms and vessel imaging. There was strong interrater agreement on artifact volume (r² = 0.927). Among patients with discordant T_max imaging, the median artifactual volume was 12cc (IQR 3-21cc), accounting for a median of 8% of the automated T_max > 6 seconds volume (IQR 3-16%, range 1-64%). Recalculation of the T_max > 6 seconds volume resulted in 1 patient being reclassified as having an "unfavorable" mismatch ratio (2.04-1.40).

CONCLUSION

Nearly half of patients had evidence of artifactual penumbral imaging on automated CTP, which rarely lead to misclassification of thrombectomy eligibility. Although artifactual findings are reliably identified by trained raters, our results emphasize the need to evaluate CTP results with knowledge of the patient's clinical symptoms and vascular imaging.

[Mobile Stoke Unit : Changes in the concept of stroke care over time]

BACKGROUND

Stroke continues to be a major cause of death and one of the most frequent reasons for permanent disability and dependence on caregiving at an adult age, whereby ischemic stroke is regarded as a medical condition that can be treated. One of the main reasons why patients with acute stroke are not given causal or evidence-based treatment is the delay in reaching a treatment-specialized team at a suitable clinic. After the dawning of the age of neurothrombectomy, various management concepts have been established to transfer the patient to a center with the appropriate level of treatment as quickly as possible (time is brain).

METHODS

The Mobile Stroke Unit (MSU) is an ambulance that contains all the equipment required to clarify the cause of a stroke and thus enables treatment and triage decision-making at the scene of the emergency.

RESULTS

Due to prehospital implementation of the "need-for-speed" notion, the MSU assumes a special role. Present data indicate a benefit with regard to a shortening of time to thrombolysis and an increase in treatment rates within the first (golden) hour. In addition, it is possible to make a diagnosis-based triage decision regarding a hospital with or without an endovascular treatment option.

CONCLUSIONS

The MSU allows swifter treatment and a diagnosis-based triage decision at the scene of the emergency. It is now important to continue evaluating the clinical and socioeconomic benefit of these, at first glance expensive, preclinical tools and also continue analyzing special regional aspects as well as the pros and cons of the concepts. The recently established Prehospital Stroke Treatment Organization (PRESTO) represents a promising approach.

Mechanical thrombectomy for recurrent large vessel occlusion

Although mechanical thrombectomy (MT) has been shown in numerous trials to be a successful treatment option for patients with large vessel occlusion (LVO), there is limited information on the safety and effectiveness of the technique in cases of recurrent LVO. To this end, we performed a retrospective review of our prospectively maintained database to identify all patients that had undergone more than one MT procedure January 2008 and January 2018. The data collected on these patients included baseline demographics and any history of diabetes mellitus, hypercholesterolaemia, hypertension, atrial fibrillation or smoking. We also recorded when the symptoms had started, the patient's NIHSS and ASPECT scores, the number of passes taken, the patient's final TICI score, any complications which arose and the patient's mRS at 90 days. Our dataset encompassed 25 patients (of which 17 (68%) were female) who had undergone a total number of 52 MT's. Average age at 1st presentation was 70 ± 12.8 years. The median time between one stroke and the next was 71 days (range 1-1059, IQR 183 days). The majority of the strokes were deemed cardioembolic (86.5%) in origin. There was no significant difference in the procedure times, number of passes or TICI scores. There was a significant difference in the mRS after the 1st and 2nd events (p = 0.014) but no significant difference if the 2nd event occurred contralateral to the 1st event (p = 0.66) (n = 22). It is therefore concluded that recurrent thrombectomy can be safely performed with no significant difference in the technical aspects of the procedure.

Stent-retriever assisted vacuum-locked extraction (SAVE) versus a direct aspiration first pass technique (ADAPT) for acute stroke: data from the real-world

BACKGROUND

Embolectomy is the standard of care in acute ischemic stroke (AIS) caused by large vessel occlusion (LVO). Aim of this study was to compare two techniques: A Direct Aspiration First Pass Technique (ADAPT) and Stent-retriever Assisted Vacuum-locked Extraction (SAVE) stratified by the occluded vessel.

METHODS

One hundred seventy-one patients (71 male) treated between January 2014 and September 2017 with AIS due to LVO of the anterior circulation (55 carotid T, 94 M1, 22 M2) were included. Treatment techniques were divided into two categories: ADAPT and SAVE. Primary endpoints were successful reperfusion (mTICI ≥2b), near-perfect reperfusion (mTICI ≥2c) and groin puncture to reperfusion time. Secondary endpoints were the number of device-passes, first-pass reperfusion, the frequency of emboli to new territory (ENT), clinical outcome at 90 days, and the frequency of symptomatic intracranial hemorrhage (sICH). Analysis was performed on an intention to treat basis.

RESULTS

Overall, SAVE resulted in significant higher rates of successful reperfusion (mTICI≥2b) compared to ADAPT (93.5% vs 75.0%; p = 0.006). After stratification for the occluded vessel only the carotid T remained significant with higher rates of near-perfect reperfusion (mTICI≥2c) (55.2% vs 15.4%; p = 0.025), while for successful reperfusion a trend remained (93.1% vs 65.4%; p = 0.10). Groin to reperfusion times were not significantly different. Secondary analysis revealed higher rates of first-pass successful reperfusion (59.6% vs 33.3%; p = 0.019), higher rates of first-pass near-perfect reperfusion in the carotid T (35.4% vs 16.7%; p = 0.038) and a lower number of device-passes overall (median 1 IQR 1-2 vs 2 IQR 2-3; p <  0.001) and in the carotid T (median 2 IQR 1.3 vs 3 IQR 2-5; p <  0.001) for SAVE. Clinical outcome and safety parameters were comparable between groups.

CONCLUSIONS

Embolectomy using SAVE appears superior to ADAPT, especially for carotid T occlusions with regard to reperfusion success.

Impact of Leukoaraiosis Severity on the Association of Time to Successful Reperfusion with 90-Day Functional Outcome After Large Vessel Occlusion Stroke

The chance for a favorable outcome after mechanical thrombectomy (MT) for large vessel occlusion stroke decreases with the symptom onset-to-reperfusion time (OTR). Patients with severe leukoaraiosis are at increased risk for a poor outcome after MT. However, whether leukoaraiosis modulates to the association between OTR and 90-day functional outcome is uncertain. We retrospectively analyzed 144 consecutive patients with successful (TICI ≥ 2b/3) MT for anterior circulation large vessel occlusion within 24 h form OTR between January 2012 to November 2016. Leukoaraiosis was dichotomized to absent-to-mild (van Swieten scale score 0-2) versus moderate-to-severe (3-4) as assessed on admission head CT. Multiple linear, logistic, and ordinal regression analyses were used to determine the association between leukoaraiosis, OTR, and 90-day modified Rankin Scale (mRS) score, after adjustment for pertinent covariates. Leukoaraiosis was independently associated with the OTR on multivariable linear regression (p = 0.003). The association between OTR and 90-day outcome depended on the degree of pre-existing leukoaraiosis burden as shown by a significant leukoaraiosis-by-OTR interaction on multivariable logistic regression (OR 0.76, 95% CI 0.58-0.98, p = 0.037) and multivariable ordinal regression (OR 0.87, 95% CI 0.78-0.97, p = 0.011). Pre-existing leukoaraiosis is associated with the 90-day functional outcome after successful reperfusion and impacts the association between the OTR and 90-day mRS among patients undergoing MT. Patients with high leukoaraiosis burden need to present earlier than patients with low leukoaraiosis burden for a similar favorable outcome. Pending confirmation, these results may have important implications for optimizing patient selection for acute stroke therapies.

Dismantling the ability of CT and MRI to identify the target mismatch profile in patients with anterior circulation large vessel occlusion beyond six hours from symptom onset

PURPOSE

Patients with large vessel occlusion and target mismatch on imaging may be thrombectomy candidates in the extended time window. However, the ability of imaging modalities including non-contrast CT Alberta Stroke Program Early Computed Tomographic Scoring (CT ASPECTS), CT angiography collateral score (CTA-CS), diffusion-weighted MRI ASPECTS (DWI ASPECTS), DWI lesion volume, and DWI volume with clinical deficit (DWI + NIHSS), to identify mismatch is unknown.

METHODS

We defined target mismatch as core infarct (DWI volume) of < 70 mL, mismatch volume (tissue with TMax > 6 s) of ≥ 15 mL, and mismatch ratio of ≥ 1.8. Using experimental dismantling design, ability to identify this profile was determined for each imaging modality independently (phase 1) and then with knowledge from preceding modalities (phase 2). We used a generalized mixed model assuming binary distribution with PROC GLIMMIX/SAS for analysis.

RESULTS

We identified 32 patients with anterior circulation occlusions, presenting > 6 h from symptom onset, with National Institute of Health Stroke Scale of ≥ 6, who had CT and MR before thrombectomy. Sensitivities for identifying target mismatch increased modestly from 88% for NCCT to 91% with the addition of CTA-CS, and up to 100% for all MR-based modalities. Significant gains in specificity were observed from successive tests (29, 19, and 16% increase for DWI ASPECTS, DWI volume, and DWI + NIHSS, respectively).

CONCLUSIONS

The combination of NCCT ASPECTS and CTA-CS has high sensitivity for identifying the target mismatch in the extended time window. However, there are gains in specificity with MRI-based imaging, potentially identifying treatment candidates who may have been excluded based on CT imaging alone.

The Management of Acute Ischemic Strokes and the Prevalence of Large Vessel Occlusion in Left Ventricular Assist Device

BACKGROUND

Ischemic and hemorrhagic strokes are frequent complications among those with left ventricular assist device (LVAD). Scarce data exist regarding the prevalence of acute large vessel occlusion (LVO) and treatment of acute ischemic stroke (AIS) in this setting.

METHODS

We reviewed prospectively collected data of LVAD patient registry from a single, tertiary center from October 2004 to November 2016. Among those with AIS complications, patients were divided into early stroke (during implantation hospitalization) and late stroke (post-discharge) groups, and neuroimaging was reviewed and data on acute stroke therapy were collected.

RESULTS

Of 477 persons with LVAD, 49 (10.3%) AIS occurred. The majority (29/49, 59%) of AIS occurred in-hospital. Thirty-two (65%) persons had international normalized ratios less than 1.7 at the time of AIS, but none qualified to receive acute intravenous thrombolysis. Of 25 (51%) persons who underwent CT angiography (CTA), 33% (16/49) had acute LVOs. Thirty-one percent (5/16) of persons with acute LVOs underwent intra-arterial endovascular therapy. All of 5 cases presented with middle cerebral artery syndrome with a median pre-procedural National Institutes of Health Stroke Scale of 13 (interquartile range 10-18). Successful recanalization was achieved in all 5 cases.

CONCLUSIONS

In-hospital strokes and acute LVOs are common in LVAD-associated AIS. Prompt evaluation with CTA and endovascular therapy should be pursued for these critically ill patients.

Mechanical thrombectomy outcomes in large vessel stroke with high international normalized ratio

OBJECTIVE

Evaluating the safety and efficacy of mechanical thrombectomy (MT) in acute stroke patients due to emergent large vessel occlusion (ELVO) with high international-normalized-ratio (INR).

METHODS

Consecutive ELVO patients treated with MT were evaluated from two centers. Outcome measures included symptomatic-intracranial-hemorrhage(sICH), three-month mortality, successful reperfusion(SR), and 3-month functional-independence(FI; mRS-scores of 0-2). Additionally, a meta-analysis of available cohort studies was performed to evaluate safety and efficacy of MT in ELVO patients with high INR.

RESULTS

A total of 315 ELVO patients were evaluated. Of those 10 patients had INR >1.7 [mean age 63.5 ± 15, median NIHSS-score: 17 points (IQR 14-22)],and remaining 305 ELVO patients had INR ≤ 1.7 ([mean age 62 ± 14.4, median NIHSS-score: 17 points (IQR 12-21)]. Patients with high INR did not differ in terms of sICH (10.0% vs. 6.9%; p = .706), 3-month mortality (20.0% vs. 24.2%; p = .762), SR (88.9% vs. 69.4%; p = .209) and 3-month FI (50% vs. 49.3%; p = .762) compared to the rest. Meta-analysis of available studies (n = 5) showed that high INR was not related to sICH (OR: 0.94, 95%CI: 0.42-2.07; p = .88), 3-month mortality (OR: 1.07, 95%CI: CI 0.72-1.60; p = .73) and 3-month FI (OR: 0.69, 95%CI: 0.34-1.40; p = .30).

CONCLUSIONS

MT can be performed safely and effectively in ELVO patients with high INR.

Velocity Curvature Index: a Novel Diagnostic Biomarker for Large Vessel Occlusion

Despite being a conveniently portable technology for stroke assessment, Transcranial Doppler ultrasound (TCD) remains widely underutilized due to complex training requirements necessary to reliably obtain and interpret cerebral blood flow velocity (CBFV) waveforms. The validation of objective TCD metrics for large vessel occlusion (LVO) represents a first critical step toward enabling use by less formally trained personnel. In this work, we assess the diagnostic utility, relative to current standard CT angiography (CTA), of a novel TCD-derived biomarker for detecting LVO. Patients admitted to the hospital with stroke symptoms underwent TCD screening and were grouped into LVO and control groups based on the presence of CTA confirmed occlusion. Velocity curvature index (VCI) was computed from CBFV waveforms recorded at multiple depths from the middle cerebral arteries (MCA) of both cerebral hemispheres. VCI was assessed for 66 patients, 33 of which had occlusions of the MCA or internal carotid artery. Our results show that VCI was more informative when measured from the cerebral hemisphere ipsilateral to the site of occlusion relative to contralateral. Moreover, given any pair of bilateral recordings, VCI separated LVO patients from controls with average area under receiver operating characteristic curve of 92%, which improved to greater than 94% when pairs were selected by maximal velocity. We conclude that VCI is an analytically valid candidate biomarker for LVO diagnosis, possessing comparable accuracy, and several important advantages, relative to current TCD diagnostic methodologies.

MR Imaging Selection of Acute Stroke Patients with Emergent Large Vessel Occlusions for Thrombectomy

Acute stroke caused by large vessel occlusions (LVOs) are common. The time window to treat is up to 24 hours, and the most important factor is the size of the ischemic core. If the core is small (<70-100 mL), the penumbra must be large; penumbral imaging is unnecessary. MR imaging is precise in measuring the core, and superior to alternatives. The necessary sequences are obtainable rapidly, comparable to computed tomography scans. Available evidence suggests that most patients with LVOs are slow progressors defined as having a small core 6 hours or more after ictus onset.