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.

Regional Contributions to Poststroke Disability in Endovascular Therapy

Background and Purpose

The relative contribution of each Alberta Stroke Program Early CT Score (ASPECTS) region to poststroke disability likely varies across regions. Determining the relative weights of each ASPECTS region may improve patient selection for endovascular stroke therapy (EST).

Methods

In the combined Solitaire Flow Restoration with the Intention for Thrombectomy (SWIFT), Solitaire Flow Restoration Thrombectomy for Acute Revascularization (STAR), and Solitaire Flow Restoration with the Intention for Thrombectomy as Primary Endovascular Treatment (SWIFT PRIME) databases, we identified patients treated with the Solitaire stent retriever. Using 24-h CT scan, a multivariate ordinal regression was used to determine the relative contribution of each ASPECTS region to clinical outcome separately in each hemisphere. The coefficients from the regression were used to create a weighted ASPECTS (wASPECTS), which was compared with the original ASPECTS to predict 90-day modified Rankin Scale disability outcomes in an independent validation cohort.

Results

Among 342 patients treated with EST, the average age was 67 years, 57% were female, and the median National Institutes of Health Stroke Scale (NIHSS) score was 17 (IQR 13-20). The median ASPECTS at presentation was 8 (IQR 7-10). The most commonly involved ASPECTS regions on 24-h CT were the lentiform nuclei (70%), insula (55%), and caudate (52%). In multivariate analysis, preservation of M6 (β = 9.7) and M4 (β = 4.4) regions in the right hemisphere was most strongly predictive of good outcome. For the left hemisphere, M6 (β = 5.5), M5 (β = 4.1), and M3 (β = 3.1) generated the greatest parameter estimates, though they did not reach statistical significance. A wASPECTS incorporating all 20 parameter estimates resulted in improved discrimination against the original ASPECTS in the independent cohort (C-statistic 0.78 vs. 0.67, right hemisphere).

Conclusions

For both right and left hemisphere, preservation of the high cortical regions was more strongly associated with improved outcomes compared to the deep regions. Our findings support taking into consideration the location and relative weightings of the involved ASPECTS regions when evaluating a patient for EST.

Predictors of 30-day mortality after endovascular mechanical thrombectomy for acute ischemic stroke

OBJECTIVE

The aims of this single-center, retrospective cohort study are to assess the outcomes of endovascular mechanical thrombectomy (EMT) for acute ischemic stroke (AIS) and determine predictors of 30-day mortality at an academic comprehensive stroke center (CSC).

METHODS

We retrospectively collected data from consecutive patients who underwent EMT for AIS at our institution between April 2016 and January 2018. Primary outcome was defined as mortality within 30 days from EMT. Successful revascularization was defined as a modified Thrombolysis in Cerebral Infarction (mTICI) grade 2b-3. Statistical analyses were performed to identify predictors of 30-day mortality.

RESULTS

The study cohort was comprised 57 patients (51% male) with mean age of 72 years. Intravenous tissue plasminogen activator was administered in 51%. The median Alberta Stroke Program Early Computed Tomography Score (ASPECTS) and National Institutes of Health Stroke Scale (NIHSS) score were 8 and 20, respectively. The 30-day mortality rate was 39%. Univariate analyses found that older age (mean 77 vs. 68 years, p = 0.022), higher baseline NIHSS score (median 23 vs. 19, p = 0.032), NIHSS score at 24 h after EMT (median 14.5 vs. 7.5, p < 0.001), and lower rates of successful revascularization (59% vs. 89%, p = 0.021) were associated with 30-day mortality.

CONCLUSION

We observed a moderate rate of 30-day mortality after EMT at an academic CSC. Older age, higher baseline NIHSS score, higher NIHSS score at 24 h after thrombectomy, and lower rates of successful revascularization were predictive of 30-day mortality in univariate analysis. Further efforts to identify modifiable risk factors of mortality are warranted.

Thrombectomy for Acute Ischemic Stroke: Recent Insights and Future Directions

PURPOSE OF REVIEW

Mechanical thrombectomy has become the standard of care for acute ischemic stroke with proximal large vessel occlusions (LVO). This article reviews recent research relating to thrombectomy.

RECENT FINDINGS

Thrombectomy for anterior circulation stroke with proximal LVO was first shown to be highly efficacious within 6 h of stroke onset, but "late-window" trials have further demonstrated efficacy until 24-h postonset in select patients with salvageable tissue. However, the concept of "time is brain" remains critical. Thrombectomy trials have further stimulated worldwide efforts to develop systems of care for rapid treatment of eligible patients. Thrombectomy is cost-effective and likely to have long-term efficacy for both disability and mortality outcomes. Thrombectomy is a highly efficacious acute stroke therapy. Enduring uncertainties include efficacy in patients with premorbid disability, posterior circulation, or more distal occlusions; use of bridging thrombolysis; and optimal techniques to achieve consistent revascularization and address tandem occlusions or stenoses.

Support of New Triage Protocol among Acute Stroke Care Providers

Objective

We conducted an online survey to gauge the acceptance of sending acute stroke patients with suspected large vessel occlusion (LVO) directly to an endovascular-capable hospital (ECH) even if that means bypassing a closer alteplase-capable hospital (ACH) without endovascular capability.

Methods

The survey was composed of two cases of acute stroke, one with cortical symptoms suggestive of LVO and the other without. In each case, responders were asked to choose between triaging to a closer ACH or an ECH that is further away and to provide an opinion regarding the maximum extra travel time they would tolerate if they chose the ECH. The survey was sent electronically to national groups of neurologists, emergency department (ED) physicians, emergency medical service (EMS) directors, and stroke coordinators.

Results

There were 320 responders from 44 states, most of them with 10 years or more of experience. Most of the responders, 72.5%, chose ECH for the LVO case, while 56% chose ACH for the non-LVO case. There were marked differences in responses by specialty: neurology strongly supported ECH for LVO and strongly supported ACH for non-LVO, most ED and EMS chose ECH for both cases, and stroke coordinators were the least supportive of bypassing ACH. Almost all groups agreed on 30 min as the acceptable extra transfer time to ECH.

Conclusion

Among the survey responders, there is a broad acceptance of the idea of bypassing ACH and going straight to ECH when LVO is suspected; however, there is less agreement on triaging patients with non-LVO stroke.

A Review of Pre-Intervention Prognostic Scores for Early Prognostication and Patient Selection in Endovascular Management of Large Vessel Occlusion Stroke

BACKGROUND

Endovascular therapy (ET) has emerged as a highly effective treatment for acute large vessel occlusion stroke (LVOS). Tools that facilitate optimal patient selection of patients for ET are needed in order to maximize therapeutic benefit in a cost-effective manner. Several pre-intervention prognostic scores for prediction of outcomes in LVOS patients and patient selection for ET have been developed and validated, but their clinical use has been limited. Here, we review existing pre-intervention prognostic scores, compare their prognostic accuracies and levels of validation and identify gaps in current knowledge.

SUMMARY

We have reviewed published literature pertinent to development, validation, and implementation of pre-intervention prognostic scores for LVOS. Using receiver operating characteristic curve analysis, the prognostic accuracies of validated pre-interventional scores (Pittsburgh Response to Endovascular therapy [PRE], Totaled Health Risks in Vascular Events [THRIVE], Houston Intra-Arterial Therapy-2 (HIAT-2), Stroke Prognostication using Age and NIHSS [SPAN-100]) were compared in published work. Pre-intervention scores predicted functional out comes at 3 months with moderate prognostic accuracies (area under the receiver operator characteristic curve range 0.68-0.73). Using successful reperfusion (mTICI 2B/3) as the therapeutic objective of ET and 3-month modified Rankin Score 0-2 as good clinical outcome, patients most likely to clinically benefit from endovascular reperfusion can be identified using the PRE and HIAT-2 scores. Scores that incorporate collateral imaging or perfusion-based estimation of core and penumbra have not been published. Existing scores are predominantly limited to anterior circulation LVOS, and implementation studies of pre-interventional scores are lacking.

KEY MESSAGES

Pre-intervention prognostic scores can serve as useful adjuncts for patient selection in ET for acute LVOS. Pre-intervention scores including HIAT-2, THRIVE, SPAN-100, and PRE have comparable moderate prognostic accuracies for good 3-month outcomes and can identify patients who derive maximal benefit from successful reperfusion. Improvements in prognostic accuracy may be achieved by incorporating variables such as collateral status and perfusion imaging data. Implementation and impact studies using pre-intervention scores are needed to guide clinical application.

Endovascular Mechanical Thrombectomy in Large-Vessel Occlusion Ischemic Stroke Presenting with Low National Institutes of Health Stroke Scale: Systematic Review and Meta-Analysis

INTRODUCTION

Mechanical thrombectomy has become the standard of care for management of most large vessel occlusion (LVO) strokes. When patients with LVO present with minor stroke symptomatology, no consensus on the role of mechanical thrombectomy exists.

METHODS

A systematic review and meta-analysis were performed to identify studies that focused on mechanical thrombectomy, either as a standalone treatment or with intravenous tissue plasminogen activator (IV tPA), in patients with mild strokes with LVO, defined as a baseline National Institutes of Health Stroke Scale score ≤5 at presentation. Data on methodology, quality criteria, and outcome measures were extracted, and outcomes were compared using odds ratio as a summary statistic.

RESULTS

Five studies met the selection criteria and were included. When compared with medical therapy without IV tPA, mechanical thrombectomy and medical therapy with IV tPA were associated with improved 90-day modified Rankin Scale (mRS) score. Among medical patients who were not eligible for IV tPA, those who underwent mechanical thrombectomy were more likely to experience good 90-day mRS than those who were not. There was no significant difference in functional outcome between mechanical thrombectomy and medical therapy with IV tPA, and no treatment subgroup was associated with intracranial hemorrhage or death.

CONCLUSIONS

In patients with mild strokes due to LVO, mechanical thrombectomy and medical therapy with IV tPA led to better 90-day functional outcome. Mechanical thrombectomy plays an important role in the management of these patients, particularly in those not eligible for IV tPA.

Prehospital Computed Tomography Angiography in Acute Stroke Management

BACKGROUND

An ambulance equipped with a computed tomography (CT) scanner, a point-of-care laboratory, and telemedicine capabilities (mobile stroke unit [MSU]) has been shown to enable the delivery of thrombolysis to stroke patients directly at the emergency site, thereby significantly decreasing time to treatment. However, work-up in an MSU that includes CT angiography (CTA) may also potentially facilitate triage of patients directly to the appropriate target hospital and specialized treatment, according to their individual vascular pathology.

METHODS

Our institution manages a program investigating the prehospital management of patients with suspicion of acute stroke. Here, we report a range of scenarios in which prehospital CTA could be relevant in triaging patients to the appropriate target hospital and to the individually required treatment.

RESULTS

Prehospital CTA by use of an MSU allowed to detect large vessel occlusion of the middle cerebral artery in one patient with ischemic stroke and occlusion of the basilar artery in another, thereby allowing rational triage to comprehensive stroke centers for immediate intra-arterial treatment. In complementary cases, prehospital imaging not only allowed diagnosis of parenchymal hemorrhage with a spot sign indicating ongoing bleeding in one patient and of subarachnoid hemorrhage in another but also clarified the underlying vascular pathology, which was relevant for subsequent triage decisions.

CONCLUSION

Defining the vascular pathology by CTA directly at the emergency site may be beneficial in triaging patients with various cerebrovascular diseases to the most appropriate target hospital and specialized treatment.

Outcomes of Endovascular Thrombectomy with and without Thrombolysis for Acute Large Artery Ischaemic Stroke at a Tertiary Stroke Centre

BACKGROUND AND PURPOSE

Endovascular thrombectomy (EVT) improves the functional outcome when added to best medical therapy, including alteplase, in patients with acute ischaemic stroke secondary to large vessel occlusion (LVO) in the anterior circulation. However, the evidence for EVT in alteplase-ineligible patients is less compelling. It is also uncertain whether alteplase is necessary in patients with successful recanalization by EVT, as the treatment effect of EVT may be so powerful that bridging alteplase may not add to efficacy and may compromise safety by increasing bleeding risks. We aimed to survey the proportion of patients suitable for EVT who are alteplase-ineligible and to compare the safety and effectiveness of standard care of acute large artery ischaemic stroke by EVT plus thrombolysis with that of EVT alone in a tertiary hospital clinical stroke service.

METHODS

We performed a retrospective analysis of acute ischaemic stroke patients treated with EVT at our centre between October 2013 and April 2016, based on a registry with prospective and consecutive patient collection. Individual patient records were retrieved for review. Significant early neurological improvement was defined as a NIHSS score of 0-1, or a decrease from baseline of ≤8, at 24 h after stroke onset.

RESULTS

Fifty patients with acute ischaemic stroke secondary to LVO in the anterior circulation received EVT in this period, of whom 21 (42%) received concurrent alteplase and 29 (58%) EVT alone. The 2 groups had similar baseline characteristics and similar outcomes. Significant neurological improvement at 24 h occurred in 47.6% of the patients with EVT and bridging alteplase and in 51.7% of the patients with EVT alone (p = 0.774). Mortality during acute hospitalization was 20% for the bridging alteplase group versus 7.1% for EVT alone (p = 0.184). Intracranial haemorrhage rates were 14.3% for bridging alteplase versus 20.7% for EVT alone (p = 0.716). Local complications, groin haematoma (23.8 vs. 10.3%) and groin pseudoaneurysms (4.8 vs. 0%) (p = 0.170), were not significantly different.

CONCLUSION

Our study highlights the relatively large proportion of patients suitable for EVT who have a contraindication to alteplase and raises the hypothesis that adding alteplase to successful EVT may not be necessary to optimize functional outcome. The results are consistent with observational data from other endovascular centres and support a randomised controlled trial of EVT versus EVT with bridging alteplase.

Rescue Thrombectomy in Large Vessel Occlusion Strokes Leads to Better Outcomes than Intravenous Thrombolysis Alone: A 'Real World' Applicability of the Recent Trials

BACKGROUND

The Interventional Management of Stroke III (IMS-III) trial demonstrated no benefit for intravenous recombinant tissue plasminogen activator (IV rt-PA) followed by endovascular therapy versus IV rt-PA alone. However, IMS-III mostly included earlier generation devices. The recent thrombectomy trials have incorporated the stent-retriever technology, but their generalizability remains unknown.

METHODS

The North American Solitaire Acute Stroke (NASA) registry recruited patients treated with the Solitaire FR™ device between March 2012 and February 2013. The NASA-IMS-III-Like Group (NILG baseline NIHSS score ≥10 who received IV rt-PA) was compared to the IV rt-PA and IV + intra-arterial (IA)-IMS-III groups and the MR CLEAN, ESCAPE, SWIFT Prime, and REVASCAT trial controls to assess the stent-retriever treatment in the 'real-world' setting. The NILG was also compared to non-IV rt-PA NASA patients to evaluate the impact of IV rt-PA on thrombectomy.

RESULTS

A total of 136 of the 354 NASA patients fulfilled criteria for the NILG. Baseline characteristics were well balanced across groups. Time from onset to puncture was higher in NILG than IV+IA-IMS-III patients (274 ± 112 vs. 208 ± 47 min, p < 0.0001). Occlusions involving the intracranial ICA, MCA-M1, or basilar arteries were more common in NILG than IV+IA-IMS-III patients (91.2 vs. 47.2%, p < 0.00001). Modified thrombolysis in cerebral infarction ≥2b reperfusion was higher in NILG than IV+IA-IMS-III patients (74.3 vs. 39.6%, p < 0.00001). A 90-day modified Rankin Scale score ≤2 was more frequent in the NILG than IV+IA-IMS-III patients (51.9 vs. 40.8%, p = 0.03) and MR CLEAN (51.9 vs. 19.1%, p < 0.00001), ESCAPE (51.9 vs. 29.3%, p = 0.0002), SWIFT Prime (51.9 vs. 35.5%, p = 0.02), and REVASCAT (51.9 vs. 28.2%, p = 0.0003) controls. Symptomatic intracranial hemorrhage definitions varied across the different studies with rates ranging from 2.7% (ESCAPE) to 11.9% (NILG). The NILG 90-day mortality (24.4%) was higher than in SWIFT Prime but comparable to all other groups. IV rt-PA was an independent predictor of good outcome in NASA (OR = 2.3, 95% CI 1.2-4.7).

CONCLUSION

Our results support the 'real-world' applicability of the recent thrombectomy trials.

Early Recanalization Postintravenous Thrombolysis in Ischemic Stroke with Large Vessel Occlusion: A Digital Subtraction Angiography Study

AIMS

We aimed to evaluate early recanalization postintravenous (i.v.) tissue plasminogen activator (t-PA) by digital subtraction angiography (DSA) in acute ischemic stroke (AIS) with large vessel occlusion (LVO).

METHODS

We performed baseline CT angiography to identify LVO in AIS. Recanalization pre- and post-intra-arterial therapy (IAT) was categorized to none, partial, and global recanalization (GR). Modified Rankin Scale score ≤2 at 3 months was considered a favorable outcome.

RESULTS

Among 1610 patients with AIS, 286 received IV t-PA. Of these, 55 patients with LVO were included. The median time from IV t-PA to DSA was 120 min (interquartile range, 79-152). Recanalization post-IV t-PA was observed in seven patients (12.7%). By occlusion sites, the recanalization rates were as follows: extracranial internal carotid artery 2 of 14 (14.3%); intracranial internal carotid artery 3 of 24 (12.5%); M1 of middle cerebral artery 3 of 39 (7.7%); M2 of middle cerebral artery 1 of 40 (2.5%); vertebral artery 0 of 4; and basilar artery 0 of 7. GR post-IAT was associated with favorable outcomes (odds ratio: 8.6; 95% confidence interval, 1.5-48.0; P = 0.014).

CONCLUSION

Early recanalization assessed by DSA post-IV t-PA is rarely observed in acute ischemic stroke patients with LVO.

The Evolution of Mechanical Thrombectomy for Acute Stroke

OPINION STATEMENT

The natural history of an acute ischemic stroke from a large vessel occlusion (LVO) is poor and has long challenged stroke therapy. Recently, endovascular therapy has demonstrated superiority to medical management in appropriately selected patients. This advance has revolutionized acute care for LVO and mandates a reevaluation of the entire chain of stroke care delivery, including patient selection, intervention, and post-procedural care. Since endovascular therapy is a therapy specifically targeting LVO, its application should be restricted to those patients only. Clinical and radiologic parameters need to be considered in patient selection. Data supports that all patients over the age of 18 years presenting with a National Institutes of Health Stroke Scale (NIHSS) of 6 or greater within 6 hours of symptom onset should be considered for emergent endovascular therapy. Radiologically, those with a LVO of the internal carotid artery (ICA) or middle cerebral artery (MCA) M1 portion, intermediate or good collaterals and without large established infarct should be considered endovascular candidates. Selection beyond these parameters remains an open question and is being actively evaluated. In all cases, revascularization should be attempted with a new generation device (stentriever or direct aspiration), as these techniques are most likely to deliver adequate reperfusion. Post-revascularization, patients are closely monitored in an intensive care setting followed by discharge to rehabilitation, if required, or directly home. Patients should be evaluated in delayed fashion to assess recovery (typically at 3 months post-treatment). Ultimately, the poor natural history of ischemic stroke from LVO and the potential significant benefit from endovascular therapy over medical management alone necessitate a national response to ensure we identify and treat all eligible patients as rapidly and effectively as possible.

Society of Vascular and Interventional Neurology (SVIN) Stroke Interventional Laboratory Consensus (SILC) Criteria: A 7M Management Approach to Developing a Stroke Interventional Laboratory in the Era of Stroke Thrombectomy for Large Vessel Occlusions

Brain attack care is rapidly evolving with cutting-edge stroke interventions similar to the growth of heart attack care with cardiac interventions in the last two decades. As the field of stroke intervention is growing exponentially globally, there is clearly an unmet need to standardize stroke interventional laboratories for safe, effective, and timely stroke care. Towards this goal, the Society of Vascular and Interventional Neurology (SVIN) Writing Committee has developed the Stroke Interventional Laboratory Consensus (SILC) criteria using a 7M management approach for the development and standardization of each stroke interventional laboratory within stroke centers. The SILC criteria include: (1) manpower: personnel including roles of medical and administrative directors, attending physicians, fellows, physician extenders, and all the key stakeholders in the stroke chain of survival; (2) machines: resources needed in terms of physical facilities, and angiography equipment; (3) materials: medical device inventory, medications, and angiography supplies; (4) methods: standardized protocols for stroke workflow optimization; (5) metrics (volume): existing credentialing criteria for facilities and stroke interventionalists; (6) metrics (quality): benchmarks for quality assurance; (7) metrics (safety): radiation and procedural safety practices.

Mechanical Thrombectomy-Ready Comprehensive Stroke Center Requirements and Endovascular Stroke Systems of Care: Recommendations from the Endovascular Stroke Standards Committee of the Society of Vascular and Interventional Neurology (SVIN)

Five landmark multicenter, prospective, randomized, open-label, blinded end point clinical trials have recently demonstrated significant clinical benefit of endovascular therapy with mechanical thrombectomy in acute ischemic stroke (AIS) patients presenting with proximal intracranial large vessel occlusions. The Society of Vascular and Interventional Neurology (SVIN) appointed an expert writing committee to summarize this new evidence and make recommendations on how these data should guide emergency endovascular therapy for AIS patients.

Mechanical thrombectomy by Solitaire stent for treating acute ischemic stroke: A prospective cohort study

BACKGROUND

Acute ischemic stroke (AIS) is a worldwide serious health problem. Intravenous (IV) thrombolysis with recombinant tissue plasminogen activator (rt-PA) is the standard treatment; however, only a small number of patients benefit from it due to the strict application restrictions. Recently, more and more evidence prove mechanical thrombectomy is an effective and safe therapy of AIS.

PATIENTS AND METHODS

From December 2010 to March 2015, 83 patients who underwent mechanical thrombectomy were collected as a sample pool. All patients met the following criteria: National Institutes of Health Stroke Scale (NIHSS) score ≥10, treatment performed within 6 h from the onset of symptoms, no large hypodensity on CT or multimodal MRI, and angiography revealed occlusion of a major cerebral artery. Recanalization rates were assessed immediately post-procedure by follow-up angiography according to the thrombolysis in cerebral infarction score criteria. Assessment of the modified Rankin Scale was performed 90 days after treatment.

RESULTS

The mean age of patients was 63.3 years, and NIHSS scores 19.12 ± 4.60 at presentation. The vessel occlusions occurred in the middle cerebral artery (68.7%), distal internal carotid artery (7.2%), internal carotid artery with tandem middle cerebral artery occlusion (14.5%), basilar artery (2.4%), and vertebral artery (7.2%). Successful recanalization (TICI 3/2b) was achieved in 56 of 83 patients (67.5%). At 90-day follow-up, good clinical outcome (mRS ≤ 2) was achieved in 33 of 83 patients (39.8%), while 20 patients died (24.1%).

CONCLUSIONS

This study revealed mechanical thrombectomy with Solitaire stent device was an effective and safe therapy, which achieved a high rate of angiographic recanalization and independent outcome accompanied by a low mortality rate.