Stent retriever versus aspiration based thrombectomy: impact on first pass reperfusion, procedure time, and clinical outcomes in large vessel occlusion. Nationwide registry based cohort study.

BACKGROUND: First pass reperfusion (FPR), defined as near complete reperfusion (extended Treatment in Cerebral Ischemia (eTICI) score 2c/3) in a single attempt without rescue therapy has been proposed as a quality metric. However, it remains unclear if the thrombectomy method influences clinical outcome and FPR rate. This study evaluates whether stent retriever and aspiration based thrombectomy differ in FPR rate, technical and clinical outcomes in FPR, and multiple pass reperfusion (MPR). METHODS: This retrospective, nationwide, multicenter registry study included consecutive patients with proximal anterior or posterior circulation stroke, treated between 2018 and 2021 in Sweden. Outcome measures were FPR rate, procedure time, early neurological improvement (≥4 points on National Institutes of Health Stroke Scale (NIHSS) or a score of 0-1 at 24 hours), favorable functional outcome (modified Rankin Scale score of 0-2 or no decline at 90 days), and mortality at 90 days. RESULTS: Of 3309 patients (median age 75, median NIHSS 16), 1990 underwent stent retriever and 1319 aspiration based thrombectomy as the firstline method. No difference in FPR rate was observed. Aspiration based thrombectomy showed a shorter procedure time in the FPR group (crude OR (cOR) 6.4 min (95% CI 3.4 to 9.3), adjusted OR (aOR) 8.7 min (95% CI 1.8 to 15.6)) and MPR group (cOR 9.7 min (95% CI 4.0 to 15.4), aOR 17.4 min (95% CI 9.6 to 25.2)), and association with early neurological improvement (cOR 1.21 (95% CI 1.03 to 1.42), aOR 1.40 (95% CI 1.18 to 1.67)) and favorable functional outcome (aOR 1.22 (95% CI 1.01 to 1.47)). CONCLUSIONS: Our findings suggest that aspiration based thrombectomy was associated with a shorter procedure time and better clinical outcomes than treatment with a stent retriever. No difference was found in FPR rate.

Investigating the Role of Brain Natriuretic Peptide (BNP) and N-Terminal-proBNP in Thrombosis and Acute Ischemic Stroke Etiology.

The need for biomarkers for acute ischemic stroke (AIS) to understand the mechanisms implicated in pathological clot formation is critical. The levels of the brain natriuretic peptides known as brain natriuretic peptide (BNP) and NT-proBNP have been shown to be increased in patients suffering from heart failure and other heart conditions. We measured their expression in AIS clots of cardioembolic (CE) and large artery atherosclerosis (LAA) etiology, evaluating their location inside the clots, aiming to uncover their possible role in thrombosis. We analyzed 80 thrombi from 80 AIS patients in the RESTORE registry of AIS clots, 40 of which were of CE and 40 of LAA etiology. The localization of BNP and NT-BNP, quantified using immunohistochemistry and immunofluorescence, in AIS-associated white blood cell subtypes was also investigated. We found a statistically significant positive correlation between BNP and NT-proBNP expression levels (Spearman's rho = 0.668 p < 0.0001 *). We did not observe any statistically significant difference between LAA and CE clots in BNP expression (0.66 [0.13-3.54]% vs. 0.53 [0.14-3.07]%, p = 0.923) or in NT-proBNP expression (0.29 [0.11-0.58]% vs. 0.18 [0.05-0.51]%, p = 0.119), although there was a trend of higher NT-proBNP expression in the LAA clots. It was noticeable that BNP was distributed throughout the thrombus and especially within platelet-rich regions. However, NT-proBNP colocalized with neutrophils, macrophages, and T-lymphocytes, suggesting its association with the thrombo-inflammatory process.

Extended treatment in cerebral ischemia score 2c or 3 as goal of successful endovascular treatment is associated with clinical benefit.

BACKGROUND AND PURPOSE: Successful reperfusion, defined as a modified treatment in cerebral ischemia (mTICI) score 2b or 3, is an important goal for endovascular treatment (EVT) of stroke. Recently, an extension of the mTICI score with an additional grade 2c indicating near-complete reperfusion (expanded TICI, eTICI) and a revised definition of success as eTICI 2c or 3 were proposed. We evaluate whether eTICI 2c translates into improved clinical outcome compared to eTICI 2b. MATERIAL AND METHODS: Consecutive patients with large vessel occlusion in the anterior circulation who underwent EVT between December 2013 and December 2020 were included. Clinical outcome measures were favorable functional outcome at 90 days (modified Rankin Scale [mRS] scores 0 to 2 or return to pre-stroke mRS) and early neurological improvement (National Institutes of Health Stroke Scale [NIHSS] improvement ≥4 points or a score of 0-1 at 24 h). RESULTS: Of 1282 included patients (median age 76, median NIHSS 16), reperfusion was classified as eTICI 2b in 410 (32%), eTICI 2c in 242 (19%) and eTICI 3 in 464 (36%). eTICI 2c differed significally from 2b with respect to early neurological improvement (aOR = 1.49, 95% CI = 1.01-2.19). No statistically significant difference in favorable functional outcome at 90 days was found (eTICI 2c vs 2b, aOR = 1.31, 95% CI = 0.88-2.00). CONCLUSION: Our study indicates early clinical benefit at 24 h of achieving eTICI 2c compared to eTICI 2b, but no significant difference was seen in favorable functional outcome at 90 days. Our results support eTICI 2c and 3 as the goal of a successful thrombectomy but do not exclude eTICI 2b as an acceptable result.

White blood cell subtypes and neutrophil extracellular traps content as biomarkers for stroke etiology in acute ischemic stroke clots retrieved by mechanical thrombectomy.

BACKGROUND: Lymphocytes, macrophages, neutrophils, and neutrophil extracellular traps (NETs) associate with stroke risk factors and form a thrombus through different mechanisms. We investigated the total WBCs, WBC subtypes and NETs composition in acute ischemic stroke (AIS) clots to identify possible etiological differences that could help us further understand the process of thrombosis that leads to AIS. METHODS: AIS clots from 100 cases each of atherothrombotic (AT), cardioembolic (CE) and cryptogenic stroke etiology were collected per-pass as part of the CÚRAM RESTORE registry of AIS clots. Martius Scarlet Blue stain was used to identify the main histological components of the clots. Immunohistochemical staining was used to identify neutrophils, lymphocytes, macrophages, and NETs patterns. The cellular and histological components were quantified using Orbit Image Analysis software. RESULTS: AT clots were larger, with more red blood cells and fewer WBCs than CE clots. AT clots had more lymphocytes and cryptogenic clots had fewer macrophages than other etiologies. Most significantly, CE clots showed higher expression of neutrophils and extracellular web-like NETs compared to AT and cryptogenic clots. There was also a significantly higher distribution of web-like NETs around the periphery of the CE clots while a mixed distribution was observed in AT clots. CONCLUSION: The difference in neutrophil and NETs expression in clots from different etiologies may provide insight into the mechanism of clot formation.

Risk of de novo aneurysm formation in patients previously diagnosed with a ruptured or unruptured aneurysm: 18-year follow-up.

BACKGROUND: Data on de novo aneurysm formation after treatment for intracranial aneurysms remains scarce. We studied the incidence of de novo aneurysm formation in patients who had undergone aneurysm treatment more than 18 years prior to follow-up. As it is a disease affecting a younger patient population more specific guidelines are needed when planning a follow-up regime. METHODS: The rate of de novo aneurysm formation was assessed with Magnetic Resonance Angiography (MRA) follow-up >18 years after endovascular or microsurgical treatment for an intracranial aneurysm. Variables associated with de novo aneurysm formation were studied using logistic regression. Missing data were imputed using chained random forests. A data-driven model for the prediction of de novo aneurysm was created to calculate the relative variable importance of ten clinical features. RESULTS: De novo aneurysms were identified in 11/81 (13.6 %) patients, of whom 1 was male, over a median follow-up of 20 years. Sex was the most important variable associated with de novo aneurysm formation. Regarding the development of de novo aneurysm, men displayed an odds ratio (OR) of 0.16 (0.01-0.97), compared with women. OR for mRS score 2 or more was 0.20 (95 % CI 0.01-1.34), and OR for smokers was 3.70 (0.54-31.18). Six out of 11 patients (54.5 %) needed treatment; 1 underwent endovascular treatment (EVT) and 5 underwent microsurgical treatment (MST). The overall annual de novo aneurysm formation rate was 0.92 %. CONCLUSIONS: This study highlights the need for a longer follow-up imaging monitoring of patients that have previously undergone treatment for an intracranial aneurysm. These data are useful to take into consideration when planning a follow-up strategy.

Risk of poststroke epilepsy after reperfusion therapies: A national cohort study.

BACKGROUND AND PURPOSE: The risk of poststroke epilepsy (PSE) after endovascular treatment (EVT) is not well characterized. In this nationwide study, we assessed the risk of PSE after EVT and identified associated predictors. METHODS: We included all individuals (n = 3319) treated with EVT (±intravenous thrombolysis [IVT]) between 2015 and 2019 in the Swedish National Quality Register for EVT. Two control groups were identified from the Swedish Stroke Register: the first treated with IVT alone (n = 3132) and the second with no treatment (n = 3184), both matched for age, sex, stroke severity, and time of stroke. RESULTS: PSE developed in 7.9% (n = 410). The survival-adjusted 2-year risk was 6.5% (95% confidence interval [CI] = 5.28-7.70) after EVT, 10.0% (95% CI = 8.25-11.75) after IVT, and 12.3% after no revascularization (95% CI = 10.33-14.25). The hazard ratio (HR) of PSE after EVT was almost half compared to no treatment (HR = 0.51, 95% CI = 0.41-0.64). The risk of PSE after EVT was lower compared to no treatment in a multivariable Cox model that adjusted for age, sex, hemicraniectomy, and stroke severity (HR = 0.76, 95% CI = 0.60-0.96). Multivariable predictors of PSE after EVT were large infarction on computed tomography Day 1, high posttreatment National Institutes of Health Stroke Scale score, and need of assistance 3 months after stroke. IVT before EVT was associated with a lower risk of PSE (HR = 0.66, 95% CI = 0.46-0.94). CONCLUSIONS: This nationwide study identified a reduced risk of PSE after EVT. Markers of severe infarction after EVT were associated with PSE, whereas IVT given before EVT was protective.

Cancer and stroke: commonly encountered by clinicians, but little evidence to guide clinical approach.

The association between stroke and cancer is well-established. Because of an aging population and longer survival rates, the frequency of synchronous stroke and cancer will become even more common. Different pathophysiologic mechanisms have been proposed how cancer or cancer treatment directly or via coagulation disturbances can mediate stroke. Increased serum levels of D-dimer, fibrin degradation products, and CRP are more often seen in stroke with concomitant cancer, and the clot retrieved during thrombectomy has a more fibrin- and platelet-rich constitution compared with that of atherosclerotic etiology. Multiple infarctions are more common in patients with active cancer compared with those without a cancer diagnosis. New MRI techniques may help in detecting typical patterns seen in the presence of a concomitant cancer. In ischemic stroke patients, a newly published cancer probability score can help clinicians in their decision-making when to suspect an underlying malignancy in a stroke patient and to start cancer-screening studies. Treating stroke patients with synchronous cancer can be a delicate matter. Limited evidence suggests that administration of intravenous thrombolysis appears safe in non-axial intracranial and non-metastatic cancer patients. Endovascular thrombectomy is probably rather safe in these patients, but probably futile in most patients placed on palliative care due to their advanced disease. In this topical review, we discuss the epidemiology, pathophysiology, and prognosis of ischemic and hemorrhagic strokes as well as cerebral venous thrombosis and concomitant cancer. We further summarize the current evidence on acute management and secondary preventive therapy.

Potential Biomarkers of Acute Ischemic Stroke Etiology Revealed by Mass Spectrometry-Based Proteomic Characterization of Formalin-Fixed Paraffin-Embedded Blood Clots.

Background and Aims: Besides the crucial role in the treatment of acute ischemic stroke (AIS), mechanical thrombectomy represents a unique opportunity for researchers to study the retrieved clots, with the possibility of unveiling biological patterns linked to stroke pathophysiology and etiology. We aimed to develop a shotgun proteomic approach to study and compare the proteome of formalin-fixed paraffin-embedded (FFPE) cardioembolic and large artery atherosclerotic (LAA) clots. Methods: We used 16 cardioembolic and 15 LAA FFPE thrombi from 31 AIS patients. The thrombus proteome was analyzed by label-free quantitative liquid chromatography-tandem mass spectrometry (LC-MS/MS). MaxQuant v1.5.2.8 and Perseus v.1.6.15.0 were used for bioinformatics analysis. Protein classes were identified using the PANTHER database and the STRING database was used to predict protein interactions. Results: We identified 1,581 protein groups as part of the AIS thrombus proteome. Fourteen significantly differentially abundant proteins across the two etiologies were identified. Four proteins involved in the ubiquitin-proteasome pathway, blood coagulation or plasminogen activating cascade were identified as significantly abundant in LAA clots. Ten proteins involved in the ubiquitin proteasome-pathway, cytoskeletal remodeling of platelets, platelet adhesion or blood coagulation were identified as significantly abundant in cardioembolic clots. Conclusion: Our results outlined a set of 14 proteins for a proof-of-principle characterization of cardioembolic and LAA FFPE clots, advancing the proteome profile of AIS human thrombi and understanding the pathophysiology of ischemic stroke.

Prediction of Outcome After Endovascular Embolectomy in Anterior Circulation Stroke Using Biomarkers.

Stroke is a major public health problem that can cause a long-term disability or death due to brain damage. Serious stroke is frequently caused by a large vessel occlusion in the anterior circulation, which should be treated by endovascular embolectomy if possible. In this study, we investigated the use of the brain damage biomarkers tau, NFL, NSE, GFAp, and S100B to understand the progression of nervous tissue damage and their relationship to outcome in such stroke after endovascular treatment. Blood samples were taken from 90 patients pre-treatment and 2 h, 24 h, 48 h, 72 h and 3 months after endovascular treatment. Stroke-related neurological deficit was estimated using the National Institute of Health Stroke Scale (NIHSS) at admission and at 24 h. Neurological outcome was evaluated at 3 months. After stroke, tau, NFL, GFAp and S100B increased in a time dependent manner, while NSE remained constant over time. At 3 months, tau and GFAp levels were back to normal whereas NFL was still high. Tau, NFL and GFAp correlated well to outcome, as well as to infarct volume and NIHSS at 24 h. The best time for prediction of poor outcome was different for each biomarker. However, the combination of NIHSS at 24 h with either tau, NFL or GFAp at 48 h gave the best prediction. The use of biomarkers in the early setting after endovascular treatment of stroke will lead to a simplified and standardized way to estimate the nervous tissue damage and possibly complement the clinical judgement in foreseeing the need of rehabilitation measures.

Blood Pressure After Endovascular Thrombectomy and Outcomes in Patients With Acute Ischemic Stroke: An Individual Patient Data Meta-analysis.

BACKGROUND AND OBJECTIVES: To explore the association between blood pressure (BP) levels after endovascular thrombectomy (EVT) and the clinical outcomes of patients with acute ischemic stroke (AIS) patients with large vessel occlusion (LVO). METHODS: A study was eligible if it enrolled patients with AIS >18 years of age with an LVO treated with either successful or unsuccessful EVT and provided either individual or mean 24-hour systolic BP values after the end of the EVT procedure. Individual patient data from all studies were analyzed with a generalized linear mixed-effects model. RESULTS: A total of 5,874 patients (mean age 69 ± 14 years; 50% women; median NIH Stroke Scale score on admission 16) from 7 published studies were included. Increasing mean systolic BP levels per 10 mm Hg during the first 24 hours after the end of the EVT were associated with a lower odds of functional improvement (unadjusted common odds ratio [OR] 0.82, 95% confidence interval [CI] 0.80-0.85; adjusted common OR 0.88, 95% CI 0.84-0.93) and modified Rankin Scale score ≤2 (unadjusted OR 0.82, 95% CI 0.79-0.85; adjusted OR 0.87, 95% CI 0.82-0.93) and a higher odds of all-cause mortality (unadjusted OR 1.18, 95% CI 1.13-1.24; adjusted OR 1.15, 95% CI 1.06-1.23) at 3 months. Higher 24-hour mean systolic BP levels were also associated with an increased likelihood of early neurologic deterioration (unadjusted OR 1.14, 95% CI 1.07-1.21; adjusted OR 1.14, 95% CI 1.03-1.24) and a higher odds of symptomatic intracranial hemorrhage (unadjusted OR 1.20, 95% CI 1.09-1.29; adjusted OR 1.20, 95% CI 1.03-1.38) after EVT. DISCUSSION: Increased mean systolic BP levels in the first 24 hours after EVT are independently associated with a higher odds of symptomatic intracranial hemorrhage, early neurologic deterioration, 3-month mortality, and worse 3-month functional outcomes.

Does prior administration of rtPA influence acute ischemic stroke clot composition? Findings from the analysis of clots retrieved with mechanical thrombectomy from the RESTORE registry.

BACKGROUND AND PURPOSE: There is still much debate whether bridging-therapy [intravenous thrombolysis (IVT) prior to mechanical thrombectomy (MT)] might be beneficial compared to MT alone. We investigated the effect of IVT on size and histological composition of the clots retrieved from patients undergoing bridging-therapy or MT alone. METHODS: We collected mechanically extracted thrombi from 1000 acute ischemic stroke (AIS) patients included in RESTORE registry. Patients were grouped according to the administration (or not) of IVT before thrombectomy. Gross photos of each clot were taken and Extracted Clot Area (ECA) was measured using ImageJ software. Martius Scarlett Blue stain was used to characterize the main histological clot components [red blood cells (RBCs), fibrin (FIB), platelets/other (PTL)] and Orbit Image Analysis was used for quantification. Additionally, we calculated the area of each main component by multiplying the component percent by ECA. Chi-squared and Kruskal-Wallis tests were used for statistical analysis. RESULTS: 451 patients (45%) were treated with bridging-therapy while 549 (55%) underwent MT alone. When considering only percent histological composition, we did not find any difference in RBC% (P = 0.895), FIB% (P = 0.458) and PTL% (P = 0.905). However, bridging-therapy clots were significantly smaller than MT-alone clots [32.7 (14.8-64.9) versus 36.8 (20.1-79.8) mm2, N = 1000, H1 = 7.679, P = 0.006*]. A further analysis expressing components per clot area showed that clots retrieved from bridging-therapy cases contained less RBCs [13.25 (4.29-32.06) versus 14.97 (4.93-39.80) mm2, H1 = 3.637, P = 0.056] and significantly less fibrin [9.10 (4.62-17.98) versus 10.54 (5.57-22.48) mm2, H1 = 7.920, P = 0.005*] and platelets/other [5.04 (2.26-11.32) versus 6.54 (2.94-13.79) mm2, H1 = 9.380, P = 0.002*] than MT-alone clots. CONCLUSIONS: Our results suggest that previous IVT administration significantly reduces thrombus size, proportionally releasing all the main histological components.

Intra-arterial nimodipine for severe cerebral vasospasm after aneurysmal subarachnoid haemorrhage - neurological and radiological outcome.

OBJECTIVES: Cerebral vasospasm is a known complication to aneurysmal subarachnoid haemorrhage, which can lead to severe morbidity. Intra-arterial vasodilation therapy is widely used as a last resort treatment in patients with symptomatic refractory cerebral vasospasm but there is limited data about the outcome. The purpose of this study is to evaluate the neurological and radiological outcome in patients treated with intra-arterial nimodipine in relation to cerebral infarction, procedure-related complications and clinical outcome. METHODS: Patients with refractory cerebral vasospasm treated with intra-arterial nimodipine during 2009-2020 at Sahlgrenska University Hospital were retrospectively reviewed. Neurological outcome (modified Rankin Scale) at 30 days and 6 months, development of cerebral infarction after intra-arterial nimodipine treatment and procedure-related complications were studied. RESULTS: Forty-eight patients were treated with intra-arterial nimodipine. A good outcome (modified Rankin Scale 0-2) was seen in 25% (n = 12) of the patients after 30 days and in 47% (n = 22) of the patients after six months. Infarction related to the vasospastic vessel after treatment with intra-arterial nimodipine was seen in 60% (n = 29) of the patients. A total of 124 procedures with intra-arterial nimodipine were performed where complications were seen in 10 (21%) patients in 10 (8%) procedures. Four (8%) patients died within 30 days. CONCLUSIONS: A majority of patients developed an ischaemic cerebral infarction in spite of intra-arterial nimodipine treatment. However, a good clinical recovery was seen in almost half of the patients after 6 months. Minor complications occurred in one out of five patients.

Dural arteriovenous fistulas in cerebral venous thrombosis: Data from the International Cerebral Venous Thrombosis Consortium: Data from the International Cerebral Venous Thrombosis Consortium.

BACKGROUND AND PURPOSE: To explore the prevalence, risk factors, time correlation, characteristics and clinical outcome of dural arteriovenous fistulas (dAVFs) in a cerebral venous thrombosis (CVT) population. METHODS: We included patients from the International CVT Consortium registries. Diagnosis of dAVF was confirmed centrally. We assessed the prevalence and risk factors for dAVF among consecutive CVT patients and investigated its impact on clinical outcome using logistic regression analysis. We defined poor outcome as modified Rankin Scale score 3-6 at last follow-up. RESULTS: dAVF was confirmed in 29/1218 (2.4%) consecutive CVT patients. The median (interquartile range [IQR]) follow-up time was 8 (5-23) months. Patients with dAVF were older (median [IQR] 53 [44-61] vs. 41 [29-53] years; p < 0.001), more frequently male (69% vs. 33%; p < 0.001), more often had chronic clinical CVT onset (>30 days: 39% vs. 7%; p < 0.001) and sigmoid sinus thrombosis (86% vs. 51%; p < 0.001), and less frequently had parenchymal lesions (31% vs. 55%; p = 0.013) at baseline imaging. Clinical outcome at last follow-up did not differ between patients with and without dAVF. Additionally, five patients were confirmed with dAVF from non-consecutive CVT cohorts. Among all patients with CVT and dAVF, 17/34 (50%) had multiple fistulas and 23/34 (68%) had cortical venous drainage. Of 34 patients with dAVF with 36 separate CVT events, 3/36 fistulas (8%) were diagnosed prior to, 20/36 (56%) simultaneously and 13/36 after (36%, median 115 [IQR 38-337] days) diagnosis of CVT. CONCLUSIONS: Dural arteriovenous fistulas occur in at least 2% of CVT patients and are associated with chronic CVT onset, older age and male sex. Most CVT-related dAVFs are detected simultaneously or subsequently to diagnosis of CVT.

S100b in acute ischemic stroke clots is a biomarker for post-thrombectomy intracranial hemorrhages.

Background and purpose: Post-thrombectomy intracranial hemorrhages (PTIH) are dangerous complications of acute ischemic stroke (AIS) following mechanical thrombectomy. We aimed to investigate if S100b levels in AIS clots removed by mechanical thrombectomy correlated to increased risk of PTIH. Methods: We analyzed 122 thrombi from 80 AIS patients in the RESTORE Registry of AIS clots, selecting an equal number of patients having been pre-treated or not with rtPA (40 each group). Within each subgroup, 20 patients had developed PTIH and 20 patients showed no signs of hemorrhage. Gross photos of each clot were taken and extracted clot area (ECA) was measured using ImageJ. Immunohistochemistry for S100b was performed and Orbit Image Analysis was used for quantification. Immunofluorescence was performed to investigate co-localization between S100b and T-lymphocytes, neutrophils and macrophages. Chi-square or Kruskal-Wallis test were used for statistical analysis. Results: PTIH was associated with higher S100b levels in clots (0.33 [0.08-0.85] vs. 0.07 [0.02-0.27] mm2, H1 = 6.021, P = 0.014*), but S100b levels were not significantly affected by acute thrombolytic treatment (P = 0.386). PTIH was also associated with patients having higher NIHSS at admission (20.0 [17.0-23.0] vs. 14.0 [10.5-19.0], H1 = 8.006, P = 0.005) and higher number of passes during thrombectomy (2 [1-4] vs. 1 [1-2.5], H1 = 5.995, P = 0.014*). S100b co-localized with neutrophils, macrophages and with T-lymphocytes in the clots. Conclusions: Higher S100b expression in AIS clots, higher NIHSS at admission and higher number of passes during thrombectomy are all associated with PTIH. Further investigation of S100b expression in AIS clots by neutrophils, macrophages and T-lymphocytes could provide insight into the role of S100b in thromboinflammation.

Correlation between acute ischaemic stroke clot length before mechanical thrombectomy and extracted clot area: Impact of thrombus size on number of passes for clot removal and final recanalization.

INTRODUCTION: We assessed the correlation between thrombus size before and after mechanical thrombectomy, measured as length by Computed Tomography Angiography/Non-Contrast Computed Tomography (CTA/NCCT) and Extracted Clot Area, ECA, respectively. We also assessed the influence of thrombus size on the number of passes required for clot removal and final recanalization outcome. MATERIALS AND METHODS: Acute ischaemic stroke (AIS) thrombi retrieved by mechanical thrombectomy from 500 patients and data of clot length by CTA/NCCT were collected from three hospitals in Europe. ECA was obtained by measuring the area of the extracted clot. Non-parametric tests were used for data analysis. RESULTS: A strong positive correlation was found between clot length on CTA/NCCT and ECA (rho = 0.619,N = 500,P < 0.0001*). Vessel size influences clot length on CTA/NCCT (H2 = 98.6, P < 0.0001*) and ECA (H2 = 105.6,P < 0.0001*), but the significant correlation between CTA/NCCT length and ECA was evident in all vessels. Poorer revascularisation outcome was associated with more passes (H5 = 73.1, P < 0.0001*). More passes were required to remove longer clots (CTA/NCCT; H4 = 31.4, P < 0.0001*; ECA; H4 = 50.2, P < 0.0001*). There was no significant main association between recanalization outcome and length on CTA/NCCT or ECA, but medium sized clots (ECA 20-40 mm2) were associated with least passes and highest revascularisation outcome (N = 500, X2 = 16.2, P < 0.0001*). CONCLUSION: Clot length on CTA/NCCT strongly correlates with ECA. Occlusion location influences clot size. More passes are associated with poorer revascularisation outcome and bigger clots. The relationship between size and revascularisation outcome is more complex. Clots of medium ECA take less passes to remove and are associated with better recanalization outcome than both smaller and larger clots.

Characterization of the 'White' Appearing Clots that Cause Acute Ischemic Stroke.

OBJECTIVES: Most clots retrieved from patients with acute ischemic stroke are 'red' in color. 'White' clots represent a less common entity and their histological composition is less known. Our aim was to investigate the composition, imaging and procedural characteristics of 'white' clots retrieved by mechanical thrombectomy. MATERIALS AND METHODS: Seventy five 'white' thrombi were selected by visual inspection from a cohort of 760 clots collected as part of the RESTORE registry. Clots were evaluated histopathologically. RESULTS: Quantification of Martius Scarlett Blue stain identified platelets/other as the major component in 'white' clots' (mean of 55% of clot overall composition) followed by fibrin (31%), red blood cells (6%) and white blood cells (3%). 'White' clots contained significantly more platelets/other (p<0.001*) and collagen/calcification (p<0.001*) and less red blood cells (p<0.001*) and white blood cells (p=0.018*) than 'red' clots. The mean platelet and von Willebrand Factor expression was 43% and 24%, respectively. Adipocytes were found in four cases. 'White' clots were significantly smaller (p=0.016*), less hyperdense (p=0.005*) on computed tomography angiography/non-contrast CT and were associated with a smaller extracted clot area (p<0.001*) than 'red' clots. They primarily caused the occlusion of middle cerebral artery, were less likely to be removed by aspiration and more likely to require rescue-therapy for retrieval. CONCLUSIONS: 'White' clots represented 14% of our cohort and were platelet, von Willebrand Factor and collagen/calcification-rich. 'White' clots were smaller, less hyperdense, were associated with significantly more distal occlusions and were less successfully removed by aspiration alone than 'red' clots.

EndoVAscular treatment and ThRombolysis for Ischemic Stroke Patients (EVA-TRISP) registry: basis and methodology of a pan-European prospective ischaemic stroke revascularisation treatment registry.

PURPOSE: The Thrombolysis in Ischemic Stroke Patients (TRISP) collaboration was a concerted effort initiated in 2010 with the purpose to address relevant research questions about the effectiveness and safety of intravenous thrombolysis (IVT). The collaboration also aims to prospectively collect data on patients undergoing endovascular treatment (EVT) and hence the name of the collaboration was changed from TRISP to EVA-TRISP. The methodology of the former TRISP registry for patients treated with IVT has already been published. This paper focuses on describing the EVT part of the registry. PARTICIPANTS: All centres committed to collecting predefined variables on consecutive patients prospectively. We aim for accuracy and completeness of the data and to adapt local databases to investigate novel research questions. Herein, we introduce the methodology of a recently constructed academic investigator-initiated open collaboration EVT registry built as an extension of an existing IVT registry in patients with acute ischaemic stroke (AIS). FINDINGS TO DATE: Currently, the EVA-TRISP network includes 20 stroke centres with considerable expertise in EVT and maintenance of high-quality hospital-based registries. Following several successful randomised controlled trials (RCTs), many important clinical questions remain unanswered in the (EVT) field and some of them will unlikely be investigated in future RCTs. Prospective registries with high-quality data on EVT-treated patients may help answering some of these unanswered issues, especially on safety and efficacy of EVT in specific patient subgroups. FUTURE PLANS: This collaborative effort aims at addressing clinically important questions on safety and efficacy of EVT in conditions not covered by RCTs. The TRISP registry generated substantial novel data supporting stroke physicians in their daily decision making considering IVT candidate patients. While providing observational data on EVT in daily clinical practice, our future findings may likewise be hypothesis generating for future research as well as for quality improvement (on EVT). The collaboration welcomes participation of further centres willing to fulfill the commitment and the outlined requirements.

Maintenance of Acute Stroke Care Service During the COVID-19 Pandemic Lockdown.

[Figure: see text].

Neurological Outcome, Mental Fatigue, and Occurrence of Aneurysms >15 Years After Aneurysmal Subarachnoid Hemorrhage.

OBJECTIVE: Long-term data on neurological and radiological outcome after aneurysmal subarachnoid hemorrhage (aSAH) are scarce. The aim of this study was to report neurological and radiological outcome >15 years after aSAH. METHODS: Patients with aSAH who were randomly assigned to endovascular treatment (EVT) or microsurgical treatment (MST) during 1997-2001 were included. Main end points were neurological outcome assessed by modified Rankin Scale, fatigue assessed by mental fatigue scale, and radiological outcome assessed by magnetic resonance angiography. Results for mental fatigue scale were compared with a control group. RESULTS: After 15-21 years, 46 (62.2%) of the 74 survivors replied to a questionnaire. Of these patients, 18 received MST, and 28 received EVT. Modified Rankin Scale score of 0-2 was found in 100% of patients in the EVT group and 88.8% of patients in the MST group. Moderate or severe mental fatigue was found in 7/28 patients (25%) in the EVT group and 7/18 patients (38.8%) in the MST group (P < 0.05), whereas moderate or severe mental fatigue was observed in 3/34 patients (8.9%) in the control group. Magnetic resonance angiography was performed in 29 patients. In the EVT group, new neck remnants were found in 2/16 patients (12.5%), and de novo aneurysm was found in 2/16 patients (12.5%). In the MST group, de novo aneurysm was found in 1/13 patients (7.7%). CONCLUSIONS: Neurological outcome at long-term follow-up after aSAH was good; however, mental fatigue was overrepresented in patients compared with healthy control subjects regardless of treatment modality. Residual or de novo aneurysm was found in 17% of patients warranting radiological long-term follow-up.

The administration of rtPA before mechanical thrombectomy in acute ischemic stroke patients is associated with a significant reduction of the retrieved clot area but it does not influence revascularization outcome.

Both intravenous thrombolysis (IVT) and mechanical thrombectomy (MT) are evidence-based treatments for acute ischemic stroke (AIS) in selected cases. Recanalization may occur following IVT without the necessity of further interventions or requiring a subsequent MT procedure. IVT prior to MT (bridging-therapy) may be associated with benefits or hazards. We studied the retrieved clot area and degree of recanalization in patients undergoing MT or bridging-therapy for whom it was possible to collect thrombus material. We collected mechanically extracted thrombi from 550 AIS patients from four International stroke centers. Patients were grouped according to the administration (or not) of IVT before thrombectomy and the mechanical thrombectomy approach used. We assessed the number of passes for clot removal and the mTICI (modified Treatment In Cerebral Ischemia) score to define revascularization outcome. Gross photos of each clot were taken and the clot area was measured with ImageJ software. The non-parametric Kruskal-Wallis test was used for statistical analysis. 255 patients (46.4%) were treated with bridging-therapy while 295 (53.6%) underwent MT alone. By analysing retrieved clot area, we found that clots from patients treated with bridging-therapy were significantly smaller compared to those from patients that underwent MT alone (H1 = 10.155 p = 0.001*). There was no difference between bridging-therapy and MT alone in terms of number of passes or final mTICI score. Bridging-therapy was associated with significantly smaller retrieved clot area compared to MT alone but it did not influence revascularization outcome.