Rescue Stent Placement for Acute Ischemic Stroke with Large Vessel Occlusion Refractory to Mechanical Thrombectomy: A Multiethnic Middle Eastern/African/Asian Cohort.

PURPOSE: To investigate the safety and effectiveness of rescue stent placement in patients who experienced acute stroke in whom mechanical thrombectomy failed. METHODS: This was a retrospective review of a multiethnic stroke database. After stent placement, an aggressive antiplatelet protocol was followed with glycoprotein IIb/IIIa infusion. The primary outcomes were incidence of intracerebral hemorrhage (ICH), recanalization score, and favorable prognosis (modified Rankin score ≤ 2) at 90 days. A comparison was made between patients from the Middle East and North Africa (MENA) region and those from other regions. RESULTS: Fifty-five patients were included, with 87% being men. The mean age was 51.3 years (SD ±11.8); 32 patients (58%) were from South Asia, 12 (22%) from MENA, 9 (16%) from Southeast Asia, and 2 (4%) from elsewhere. Successful recanalization (modified Thrombolysis in Cerebral Infarction score = 2b/3) was achieved in 43 patients (78%), and symptomatic ICH occurred in 2 patients (4%). A favorable outcome at 90 days was seen in 26 of the 55 patients (47%). Apart from significantly older age-mean, 62.8 years (SD ±13; median, 69 years) versus 48.1 years (SD ±9.3; median, 49 years)-and coronary artery disease burden-4 (33%) versus 1 (2%) (P < .05), patients from MENA had risk factors, stroke severity, recanalization rates, ICH rates, and 90-day outcomes similar to those from South and Southeast Asia. CONCLUSION: Rescue stent placement showed good outcomes and a low risk of clinically significant bleeding in a multiethnic cohort of patients from MENA and South and Southeast Asia, similar to that in published literature.

The Need for Structured Strategies to Improve Stroke Care in a Rural Telestroke Network in Northern New South Wales, Australia: An Observational Study.

Introduction: A telestroke network in Northern New South Wales, Australia has been developed since 2017. We theorized that the telestroke network development would drive a progressive improvement in stroke care metrics over time. Aim: This study aimed to describe changes in acute stroke workflow metrics over time to determine whether they improved with network experience. Methods: We prospectively collected data of patients assessed by telestroke who received multimodal computed tomography (mCT) and were diagnosed with ischemic stroke or transient ischemic attack from January 2017 to July 2019. The period was divided into two phases (phase 1: January 2017 - October 2018 and phase 2: November 2018 - July 2019). We compared median door-to-call, door-to-image, and door-to-decision time between the two phases. Results: We included 433 patients (243 in phase 1 and 190 in phase 2). Each spoke site treated 1.5-5.2 patients per month. There were Door-to-call time (median 39 in phase 1, 35 min in phase 2, p = 0.18), and door-to-decision time (median 81.5 vs. 83 min, p = 0.31) were not improved significantly. Similarly, in the reperfusion therapy subgroup, door-to-call time (median 29 vs. 24.5 min, p = 0.12) and door-to-decision time (median 70.5 vs. 67.5 min, p = 0.75) remained substantially unchanged. Regression analysis showed no association between time in the network and door-to-decision time (coefficient 1.5, p = 0.32). Conclusion: In our telestroke network, acute stroke timing metrics did not improve over time. There is the need for targeted education and training focusing on both stroke reperfusion competencies and the technical aspects of telestroke in areas with limited workforce and high turnover.

Air vs. Road Decision for Endovascular Clot Retrieval in a Rural Telestroke Network.

Background and Purpose: Telestroke aims to increase access to endovascular clot retrieval (ECR) for rural areas. There is limited information on transfer workflow for ECR in rural settings. We sought to describe the transfer metrics for ECR in a rural telestroke network with respect to decision making. Methods: A retrospective cohort study was employed on consecutive patients transferred to the comprehensive stroke center (CSC) for ECR in a rural hub-and-spoke telestroke network between April 2013 and October 2019, by road or air. Key time-based metrics were analyzed. Results: Sixty-two patients were included. Mean age was 66 years [standard deviation (SD), 14] and median National Institutes of Health Stroke Scale 13 [interquartile range (IQR), 8-18]. Median rural-hospital-door-to-CSC-door (D2D) was 308 min (IQR, 254-351), of which 68% was spent at rural hospitals [door-in-door-out (DIDO); 214 min; IQR, 171-247]. DIDO was longer for air transfers than road (P = 0.004), primarily because of a median 87 min greater decision-to-departure time (Decision-DO, P < 0.001). In multiple linear regression analysis, intubation but not thrombolysis was associated with significantly longer DIDO. The distance at which the extra speed of an aircraft made up for the delays involved in booking an aircraft was 299 km from the CSC. Conclusions: DIDO is longer for air retrievals compared with road. Decision-DO represents the most important component of DIDO, being longer for air transfers. Systems for rapid transportation of rural ECR candidates need optimization for best patient outcomes, with decision support seen as a potential tool to achieve this.

No Evidence of the "Weekend Effect" in the Northern New South Wales Telestroke Network.

Background: Admission outside normal business hours has been associated with prolonged door-to-treatment times and poorer patient outcomes, the so called "weekend effect. " This is the first examination of the weekend effect in a telestroke service that uses multi-modal computed tomography. Aims: To examine differences in workflow and triage between in-hours and out-of-hours calls to a telestroke service. Methods: All patients assessed using the Northern New South Wales (N-NSW) telestroke service from April 2013 to January 2019 were eligible for inclusion (674 in total; 539 with complete data). The primary outcomes measured were differences between in-hours and out-of-hours in door-to-call-to-decision-to-needle times, differences in the proportion of patients confirmed to have strokes or of patients selected for reperfusion therapies or patients with a modified Rankin Score (mRS ≤ 2) at 90 days. Results: There were no significant differences between in-hours and out-of-hours in any of the measured times, nor in the proportions of patients confirmed to have strokes (67.6 and 69.6%, respectively, p = 0.93); selected for reperfusion therapies (22.7 and 22.6%, respectively, p = 0.56); or independent at 3 months (34.8 and 33.6%, respectively, p = 0.770). There were significant differences in times between individual hospitals, and patient presentation more than 4.5 h after symptom onset was associated with slower times (21 minute delay in door-to-call, p = 0.002 and 22 min delay in door-to-image, p = 0.001). Conclusions: The weekend effect is not evident in the Northern NSW telestroke network experience, though this study did identify some opportunities for improvement in the delivery of acute stroke therapies.

Medical Management vs Mechanical Thrombectomy for Mild Strokes: An International Multicenter Study and Systematic Review and Meta-analysis.

Importance: The benefit of mechanical thrombectomy (MT) in patients with stroke presenting with mild deficits (National Institutes of Health Stroke Scale [NIHSS] score <6) owing to emergency large-vessel occlusion (ELVO) remains uncertain. Objective: To assess the outcomes of patients with mild-deficits ELVO (mELVO) treated with MT vs best medical management (bMM). Data Sources: We retrospectively pooled patients with mELVO during a 5-year period from 16 centers. A meta-analysis of studies reporting efficacy and safety outcomes with MT or bMM among patients with mELVO was also conducted. Data were analyzed between 2013 and 2017. Study Selection: We identified studies that enrolled patients with stroke (within 24 hours of symptom onset) with mELVO treated with MT or bMM. Main Outcomes and Measures: Efficacy outcomes included 3-month favorable functional outcome and 3-month functional independence that were defined as modified Rankin Scale scores of 0 to 1 and 0 to 2, respectively. Safety outcomes included 3-month mortality and symptomatic and asymptomatic intracranial hemorrhage (ICH). Results: We evaluated a total of 251 patients with mELVO who were treated with MT (n = 138; 65 women; mean age, 65.2 years; median NIHSS score, 4; interquartile range [IQR], 3-5) or bMM (n = 113; 51 women; mean age, 64.8; median NIHSS score, 3; interquartile range [IQR], 2-4). The rate of asymptomatic ICH was lower in bMM (4.6% vs 17.5%; P = .002), while the rate of 3-month FI (after imputation of missing follow-up evaluations) was lower in MT (77.4% vs 88.5%; P = .02). The 2 groups did not differ in any other efficacy or safety outcomes. In multivariable analyses, MT was associated with higher odds of asymptomatic ICH (odds ratio [OR], 11.07; 95% CI, 1.31-93.53; P = .03). In the meta-analysis of 4 studies (843 patients), MT was associated with higher odds of symptomatic ICH in unadjusted analyses (OR, 5.52; 95% CI, 1.91-15.49; P = .002; I2 = 0%). This association did not retain its significance in adjusted analyses including 2 studies (OR, 2.06; 95% CI, 0.49-8.63; P = .32; I2 = 0%). The meta-analysis did not document any other independent associations between treatment groups and safety or efficacy outcomes. Conclusions and Relevance: Our multicenter study coupled with the meta-analysis suggests similar outcomes of MT and bMM in patients with stroke with mELVO, but no conclusions about treatment effect can be made. The clinical equipoise can further be resolved by a randomized clinical trial.

Baseline Occlusion Angiographic Appearance on Mechanical Thrombectomy Suggests Underlying Etiology and Outcome.

Background: Etiology of a large vessel occlusion is relevant in the management of acute ischemic stroke patients and often difficult to determine in the acute phase. Aims: We aim to investigate whether the angiographic appearance of the occlusion is related to its etiology and outcome. Materials and Methods: Patients without cervical carotid occlusions who underwent mechanical thrombectomy in our center from April 2015 to September 2018 were studied. Demographics, clinical and radiological variables and outcome measures, including etiological classification of stroke, were collected. Underlying intracranial atherosclerosis was estimated according to the presence of stenosis after recanalization. Patients were assigned to groups based on the appearance of the occlusion observed in the first angiogram as "tapered" or "non-tapered." Differences were searched amongst them. Results: 131 patients met inclusion criteria. 31 (23.6%) were "tapered" and 100 (76.3%) non-tapered. Tapered presented lower mean baseline NIHSS (10.3 ± 6.2 vs. 16.1 ± 7.2; p < 0.001), smaller acute infarct cores as CTP CBV ASPECTS (8.6 ± 1.6 vs. 7.2 ± 2.4; p = 0.003), higher proportion of instant re-occlusions (26.7 vs. 8.2%; p = 0.025), fewer complete recanalization (45.2 vs. 71.0%; p = 0.028), and more persistent occlusions (37.5 vs. 10.6%; p = 0.011) on follow up MRA. There were no differences in reperfusion rates (83.9 vs. 84.0%; p = 0.986) nor in good long term functional outcome (50.0 vs. 51.1%; p = 0.921). Intracranial atherosclerosis etiology was more common in tapered than in non-tapered occlusions (54.8 vs. 18.0%; p < 0.001). Conclusion: The angiographic appearance of an occlusion in mechanical thrombectomy patients may determine its etiology, predict likelihood of successful recanalization, and risk of reocclusion.

The Impact of Diabetes on Outcomes After Acute Ischemic Stroke: A Prospective Observational Study.

BACKGROUND: Stroke in diabetics may delay recovery and increases the risk of early recurrence of stroke. We compared the outcomes of patients (with and without diabetes) admitted with an acute ischemic stroke (AIS) in the state of Qatar. PATIENTS AND METHODS: We prospectively compared the clinical presentation, complications, discharge outcome, and stroke recurrence at 90 days in patients with and without diabetes. RESULTS: Five thousand two hundred twenty-eight stroke patients were admitted between January 2014 and December 2017. Two thousand nine hundred sixty-one had confirmed AIS, 1695 (57.2%) had diabetes, 429 (14.5%) had prediabetes and 873 (29.5%) had no diabetes. Comparing diabetic patients to prediabetic and nondiabetics, they were significantly older (58.5 ± 11.9 versus 54.0 ± 12.9 versus 49.5 ± 13.8, P = .0001), had higher rates of hypertension (80.8% versus 67.4% versus 59.2%), previous stroke (18.0% versus 5.4% versus 6.2%), and coronary artery disease (12.9% versus 5.6% versus 5.0%; P = .001 for all). The percentage of patients with modified Rankin scale 3-6 at discharge (39.7% versus 32.6% versus 30.2%; P = .0001) and 90 days (26.7% versus 18.8% versus 21.4%, P = .001); 90-day mortality (6.2% versus 2.2% versus 5.2%; P = .03) and stroke recurrence (4.2% versus .7% versus 2.2%; P = .005) was significantly higher in diabetic patients. CONCLUSIONS: Patients with diabetes and AIS have more in-hospital complications, worse discharge outcomes, higher mortality and stroke recurrence at 90 days, compared to prediabetes and no diabetes.

Relative cerebral blood volume is associated with collateral status and infarct growth in stroke patients in SWIFT PRIME.

We aimed to evaluate how predefined candidate cerebral perfusion parameters correlate with collateral circulation status and to assess their capacity to predict infarct growth in patients with acute ischemic stroke (AIS) eligible for endovascular therapy. Patients enrolled in the SWIFT PRIME trial with baseline computed tomography perfusion (CTP) scans were included. RAPID software was used to calculate mean relative cerebral blood volume (rCBV) in hypoperfused regions, and hypoperfusion index ratio (HIR). Blind assessments of collaterals were performed using CT angiography in the whole sample and cerebral angiogram in the endovascular group. Reperfusion was assessed on 27-h CTP; infarct volume was assessed on 27-h magnetic resonance imaging/CT scans. Logistic and rank linear regression models were conducted. We included 158 patients. High rCBV ( p = 0.03) and low HIR ( p = 0.03) were associated with good collaterals. A positive association was found between rCBV and better collateral grades on cerebral angiography ( p = 0.01). Baseline and 27-h follow-up CTP were available for 115 patients, of whom 74 (64%) achieved successful reperfusion. Lower rCBV predicted a higher infarct growth in successfully reperfused patients ( p = 0.038) and in the endovascular treatment group ( p = 0.049). Finally, rCBV and HIR may serve as markers of collateral circulation in AIS patients prior to endovascular therapy. CLINICAL TRIAL REGISTRATION: Unique identifier: NCT0165746.

Evaluation of hyperacute infarct volume using ASPECTS and brain CT perfusion core volume.

OBJECTIVE: To compare the accuracy of Alberta Stroke Program Early Computed Tomography Score (ASPECTS) and CT perfusion to detect established infarction in acute anterior circulation stroke. METHODS: We performed an observational study in 59 acute anterior circulation ischemic stroke patients who underwent brain noncontrast CT, CT perfusion, and MRI within 100 minutes from CT imaging. ASPECTS scores were calculated by 4 blinded vascular neurologists. The accuracy of ASPECTS and CT perfusion core volume to detect an acute MRI diffusion lesion of ≥70 mL was evaluated using receiver operating characteristics analysis and optimum cutoff values were calculated using Youden J. RESULTS: Median ASPECTS score was 8 (interquartile range [IQR] 5-9). Median CT perfusion core volume was 22 mL (IQR 10.4-71.9). Median MRI diffusion lesion volume was 24.5 mL (IQR 10-63.9). No significant difference was found between the accuracy of CT perfusion and ASPECTS (c statistic 0.95 vs 0.87, p value for difference = 0.17). The optimum ASPECTS cutoff score to detect a diffusion-weighted imaging lesion ≥70 mL was <7 (sensitivity 0.74, specificity 0.86, Youden J = 0.60) and the optimum CT perfusion core volume cutoff was ≥50 mL (sensitivity 0.86, specificity 0.97, Youden J = 0.84). The CT perfusion core lesion covered a median of 100% (IQR 86%-100%) of the acute MRI lesion volume (Pearson R = 0.88; R2 = 0.77). CONCLUSIONS: We found no significant difference between the accuracy of CT perfusion and ASPECTS to predict hyperacute MRI lesion volume in ischemic stroke.

Severe cerebral vasospasm in chronic cocaine users during neurointerventional procedures: A report of two cases.

Cocaine is a widespread recreational drug that has the potential to induce neurological vascular diseases, including ischaemic and haemorrhagic stroke. Although arterial vasospasm has been suggested as a pathogenic factor in the development of neurovascular complications, it remains unclear whether cocaine users carry an increased risk to suffer iatrogenic vasospasm during endovascular procedures. We report the case of two patients with a history of cocaine abuse, who developed unusual severe vasospasms during different interventional procedures. The first case occurred in a middle-aged woman with an unruptured left internal carotid artery bifurcation aneurysm who was scheduled for treatment by remodelling assisted coiling. Just after the placement of the remodelling balloon, a severe occlusive vasospasm interrupted the procedure. The second case happened to a 46-year-old man with a non-aneurysmal subarachnoid haemorrhage and a symptomatic vasospasm in the right-sided anterior circulation who developed another occlusive vasospasm after the first attempt at transluminal balloon angioplasty. Further research is needed to establish a relation between cocaine use and increased risk of iatrogenic vasospasm in endovascular procedures, but we suggest practitioners be extremely cautious when treating this subgroup of patients.

Endovascular treatment for M2 occlusions in the era of stentrievers: a descriptive multicenter experience.

BACKGROUND: Patients with M2 middle cerebral artery (MCA) occlusions are not always considered for endovascular treatment. OBJECTIVE: To study outcomes in patients with M2 occlusion treated with endovascular procedures in the era of stentrievers. METHODS: We studied patients prospectively included in the SONIIA registry (years 2011-2012)-a mandatory, externally audited registry that monitors the quality of reperfusion therapies in Catalonia in routine practice. Good recanalization was defined as postprocedure Thrombolysis in Cerebral Infarction (TICI) score 2b-3; dramatic recovery as drop in National Institutes of Health Stroke Scale (NIHSS) score >10 points or NIHSS score <2 at 24-36 h; and good outcome as modified Rankin score (mRS) 0-2 at 3months. A 24 h CT scan determined symptomatic intracranial hemorrhage (SICH) and infarct volume. RESULTS: Of 571 patients who received endovascular treatment, 65 (11.4%) presented an M2 occlusion on initial angiogram, preprocedure NIHSS 16 (IQR 6). Mean time from symptom onset to groin puncture was 289 ± 195 min. According to interventionalist preferences 86.2% (n=56) were treated with stentrievers (n=7 in combination with intra-arterial tissue plasminogen activator (tPA), 4.6% (n=3) received intra-arterial tPA only, and 9.2% (n=6) diagnostic angiography only. Good recanalization (78.5%) was associated with dramatic improvement (48% vs 14.8%; p=0.02), smaller infarct volumes (8 vs 82 cc; p=0.01) and better outcome (mRS 0-2: 66.3% vs 30%; p=0.03). SICH (9%) was not associated with treatment modality or device used. After adjusting for age and preprocedure NIHSS, good recanalization emerged as an independent predictor of dramatic improvement (OR=5.9 (95% CI 1.2 to 29.2), p=0.03). Independent predictors of good outcome at 3 months were age ( OR=1.067 (95% CI 1.005 to 1132), p=0.03) and baseline NIHSS ( OR=1.162 (95% CI 1.041 to 1.297), p<0.01). CONCLUSIONS: Endovascular treatment of M2 MCA occlusion with stentrievers seems safe. Induced recanalization may double the chances of achieving a favorable outcome, especially for patients with moderate or severe deficit.

Relative cerebral blood volume as a marker of durable tissue-at-risk viability in hyperacute ischemic stroke.

BACKGROUND AND PURPOSE: Selection of best responders to reperfusion therapies could be aided by predicting the duration of tissue-at-risk viability, which may be dependant on collateral circulation status. We aimed to identify the best predictor of good collateral circulation among perfusion computed tomography (PCT) parameters in middle cerebral artery (MCA) ischemic stroke and to analyze how early MCA response to intravenous thrombolysis and PCT-derived markers of good collaterals interact to determine stroke outcome. METHODS: We prospectively studied patients with acute MCA ischemic stroke treated with intravenous thrombolysis who underwent PCT before treatment showing a target mismatch profile. Collateral status was assessed using a PCT source image-based score. PCT maps were quantitatively analyzed. Cerebral blood volume (CBV), cerebral blood flow, and Tmax were calculated within the hypoperfused volume and in the equivalent region of unaffected hemisphere. Occluded MCAs were monitored by transcranial Duplex to assess early recanalization. Main outcome variables were brain hypodensity volume and modified Rankin scale score at day 90. RESULTS: One hundred patients with MCA ischemic stroke imaged by PCT received intravenous thrombolysis, and 68 met all inclusion criteria. A relative CBV (rCBV) >0.93 emerged as the only predictor of good collaterals (odds ratio, 12.6; 95% confidence interval, 2.9-55.9; P=0.001). Early MCA recanalization was associated with better long-term outcome and lower infarct volume in patients with rCBV<0.93, but not in patients with high rCBV. None of the patients with rCBV<0.93 achieved good outcome in absence of early recanalization. CONCLUSIONS: High rCBV was the strongest marker of good collaterals and may characterize durable tissue-at-risk viability in hyperacute MCA ischemic stroke.

[High performance of an implantable Holter monitor in the detection of concealed paroxysmal atrial fibrillation in patients with cryptogenic stroke and a suspected embolic mechanism]. / Altorendimiento del holter implantable en la detecciónde fibrilación auricular paroxística oculta en pacientescon ictus criptogénico y sospecha de mecanismo embólico.

INTRODUCTION: Implantable loop recorders (ILR) may allow detection of occult paroxysmal atrial fibrillation (PAF) in patients with cryptogenic ischemic stroke. However, optimal selection algorithm and ideal duration of monitoring remain unclear. AIM. To determine the incidence and time-profile of PAF in patients with cryptogenic ischemic stroke studied with Reveal XT ILR, who were selected based on a high suspicion of cerebral embolism. SELECTION CRITERIA: absence of stroke etiology after complete study including vascular imaging, transesophageal echocardiography and at least 24 hours of cardiac rhythm monitoring, and confirmation of acute embolic occlusion of intracranial artery by transcranial duplex or characteristics of acute ischemic lesion on neuroimaging suggesting embolic mechanism of ischemia. After implanting Reveal XT ILR, patients were trained to perform transmissions monthly or when symptoms occurred. We reviewed the information online each month and patients underwent clinical visits at 3rd and 6th month and then every six months. RESULTS: We included 101 patients with cryptogenic ischemic stroke and at least one month of follow-up after ILR implant. Mean age was 67 years, 54 women (53.5%). Mean follow-up after implantation was 281 ± 212 days. Occult PAF was detected in 34 patients (33.7%). Frequency of false positives: 22.8%. Median time from implant to arrhythmia detection was 102 days (range: 26-240 days). 24 (70%) patients with PAF had several arrhythmic episodes detected with ILR. The majority of events (75%) were detected during the first six months of monitoring. CONCLUSIONS: In our patients with probably embolic cryptogenic ischemic stroke, PAF was detected by Reveal XT ILR in 33.7%. One in four events occurred after the first six months of monitoring.

TITLE: Alto rendimiento del holter implantable en la deteccion de fibrilacion auricular paroxistica oculta en pacientes con ictus criptogenico y sospecha de mecanismo embolico.Introduccion. El holter implantable permite detectar fibrilacion auricular paroxistica (FAP) oculta en pacientes con ictus criptogenico, pero se desconoce que algoritmo de seleccion tiene un mayor rendimiento y la duracion optima de monitorizacion. Objetivo. Conocer la frecuencia y el tiempo hasta detectar la FAP mediante un holter implantable Reveal XT ® en pacientes con ictus criptogenico seleccionados por sospecha elevada de embolismo cerebral. Pacientes y metodos. Criterios de seleccion: ausencia de etiologia del ictus tras el estudio completo incluyendo un ecocardiograma transesofagico, monitorizacion ECG y holter de 24 horas, asi como confirmacion de oclusion aguda embolica de la arteria intracraneal por duplex transcraneal o bien alta sospecha de embolismo por caracteristicas de neuroimagen. Tras implantar el holter Reveal XT se formo a los pacientes para que emprendieran transmisiones todos los meses o ante sintomas. Se reviso la informacion online mensualmente y se realizaron visitas clinicas en las unidades de Neurologia y Cardiologia. Resultados. Se incluyeron 101 pacientes con ictus criptogenico y al menos un mes de seguimiento: edad media de 67 años, 54 mujeres (53,5%). Tiempo medio de seguimiento: 281 ± 212 dias. Se detecto FAP oculta en 34 pacientes (33,7%) y falsos positivos en 23 (22,8%). Mediana desde el implante hasta la deteccion de la arritmia: 102 dias (rango: 26-240 dias). En un 70% de los pacientes se registraron multiples episodios de FAP. El 75% de los eventos se detectaron durante los primeros seis meses de monitorizacion. Conclusiones. El algoritmo de seleccion de pacientes con ictus criptogenico segun sospecha de embolismo cerebral se asocio a una elevada frecuencia (33,7%) de FAP oculta con holter implantable. Uno de cada cuatro eventos sucedio tras los primeros seis meses de monitorizacion.

Multimodal CT versus MRI in Selecting Acute Stroke Patients for Endovascular Treatment.

Arterial revascularization is the most effective therapy for acute stroke patients. Systemic thrombolysis with recombinant tissue plasminogen activator based on baseline non-contrast CT (NCCT) imaging criteria is the only treatment approved to date, which is limited by severe timing and medical restrictions, and a narrow efficacy. The simple imaging methodology required contrast with the current wide range of imaging modalities available, which permits the physician to rapidly obtain an estimation of the most relevant pathophysiological factors involved in an acute stroke, overcoming the limited capability of NCCT. Multimodal CT and MRI combine techniques that aim to depict the neurovasculature and the status of the brain parenchyma, including the presence of hemorrhage and infarction, as well as the viability of the cerebral ischemic areas involved. These additional imaging procedures have been explored in clinical studies and trials to guide intravenous thrombolysis in acute stroke patients beyond the currently established time windows, with inconclusive results. However, emergent endovascular materials and techniques are evolving, showing promising results with increasing rates of arterial recanalization with an acceptable safety profile, therefore becoming a potential alternative and complimentary treatment, although the current lack of a high level of evidence is limiting their use in routine clinical practice. Nevertheless, these advanced neuroimaging methods can be used to improve the selection of candidates for these novel invasive therapies and, moreover, to help the interventionist to design a faster and safer procedure. In this article, we review the basic aspects of both CT and MRI modalities and the state of the evidence of these imaging tools to guide endovascular therapy, as well as the advantages and disadvantages of each method.

Perfusion computed tomography-guided intravenous thrombolysis for acute ischemic stroke beyond 4.5 hours: a case-control study.

BACKGROUND: Extending the therapeutic window of intravenous thrombolysis for acute ischemic stroke beyond the established 4.5-hour limit is of critical importance in order to increase the proportion of thrombolysed stroke patients. In this setting, the capacity of MRI to select acute stroke patients for reperfusion therapies in delayed time windows has been and is being tested in clinical trials. However, whether the more available and cost-effective perfusion computed tomography (PCT) may be useful to select candidates for delayed intravenous thrombolysis remains largely unexplored. We aimed to evaluate the safety and efficacy of PCT-guided intravenous thrombolysis beyond 4.5 h after stroke onset. METHODS: We prospectively studied all consecutive acute ischemic stroke patients treated with intravenous tissue plasminogen activator (tPA) in our stroke unit between January 2008 and December 2010. Patients treated within 0- 4.5 h were treated according to non-contrast CT (NCCT) criteria. Beyond 4.5 h, patients received intravenous tPA according to PCT criteria, i.e. an infarct core on cerebral blood volume (CBV) maps not exceeding one third of the middle cerebral artery (MCA) territory and tissue at risk as defined by mean transit time-CBV mismatch greater than 20%. Predetermined primary endpoints were symptomatic hemorrhagic transformation and favorable long-term outcome, while early neurological improvement and MCA recanalization were considered secondary endpoints. Statistical analysis included bivariate comparisons between the two groups for each endpoint and logistic regression models when significance was found in bivariate analyses. This study was approved by our local ethics committee. RESULTS: A total of 245 patients received intravenous thrombolysis. After the groups were matched by baseline National Institutes of Health Stroke Scale score, 172 patients treated at <4.5 h and 43 patients treated at >4.5 h were finally included. Early and late groups were comparable regarding baseline variables; only cardioembolic etiology was more frequent in the >4.5 h group. Rates of symptomatic hemorrhagic transformation (2.9% in the <4.5 h group vs. 2.3% in the >4.5 h group; p = 1.0) and good long-term outcome (64.5 vs. 60.5%, respectively; p = 0.620) were similar between the groups. However, delayed intravenous thrombolysis was independently associated with a worse early clinical course [odds ratio (OR) 2.07, 95% confidence interval (CI) 1.04-4.1; p = 0.038] and lower 2-hour MCA recanalization rates (OR 0.4, 95% CI 0.17-0.92; p = 0.03). CONCLUSION: Primary safety and efficacy endpoints were comparable between the early and delayed thrombolysis groups. The results of our exploratory study may justify a randomized clinical trial to test the safety and efficacy of PCT-guided intravenous thrombolysis in acute ischemic stroke patients presenting beyond 4.5 h from symptom onset.

Insulin resistance is associated with a poor response to intravenous thrombolysis in acute ischemic stroke.

OBJECTIVE: Insulin resistance (IR) may not only increase stroke risk, but could also contribute to aggravate stroke prognosis. Mainly through a derangement in endogenous fibrinolysis, IR could affect the response to intravenous thrombolysis, currently the only therapy proved to be efficacious for acute ischemic stroke. We hypothesized that high IR is associated with more persistent arterial occlusions and poorer long-term outcome after stroke thrombolysis. RESEARCH DESIGN AND METHODS: We performed a prospective, observational, longitudinal study in consecutive acute ischemic stroke patients presenting with middle cerebral artery (MCA) occlusion who received intravenous thrombolysis. Patients with acute hyperglycemia (≥155 mg/dL) receiving insulin were excluded. IR was determined during admission by the homeostatic model assessment index (HOMA-IR). Poor long-term outcome, as defined by a day 90 modified Rankin scale score ≥ 3, was considered the primary outcome variable. Transcranial Duplex-assessed resistance to MCA recanalization and symptomatic hemorrhagic transformation were considered secondary end points. RESULTS: A total of 109 thrombolysed MCA ischemic stroke patients were included (43.1% women, mean age 71 years). The HOMA-IR was higher in the group of patients with poor outcome (P = 0.02). The probability of good outcome decreased gradually with increasing HOMA-IR tertiles (80.6%, 1st tertile; 71.4%, 2nd tertile; and 55.3%, upper tertile). A HOMA-IR in the upper tertile was independently associated with poor outcome when compared with the lower tertile (odds ratio [OR] 8.54 [95% CI 1.67-43.55]; P = 0.01) and was associated with more persistent MCA occlusions (OR 8.2 [1.23-54.44]; P = 0.029). CONCLUSIONS: High IR may be associated with more persistent arterial occlusions and worse long-term outcome after acute ischemic stroke thrombolysis.