Background: There are limited data on the specific mechanisms of stroke in patients with intracranial atherosclerotic stenosis (ICAS). We undertook this study to describe infarct patterns and likely mechanisms of stroke in a large cohort of patients with ICAS, and to evaluate the relationship of these infarct patterns to angiographic features (collaterals, stenosis location and stenosis severity). Methods: We evaluated infarct patterns in the territory of a stenotic intracranial artery on neuroimaging performed at baseline and during follow-up if a recurrent stroke occurred in patients enrolled in the Warfarin-Aspirin Symptomatic Intracranial Disease (WASID) trial. We defined the likely mechanism of stroke (artery-to-artery embolism, perforator occlusion, hypoperfusion or mixed) according to the site of ICAS and based on the infarct patterns on neuroimaging. Collaterals were assessed using American Society of Interventional and Therapeutic Neuroradiology/Society of Interventional Radiology (ASITN/SIR) grades, and stenosis severity using the WASID trial's measurement technique. We evaluated the association of infarct patterns with angiographic features using χ² tests. Results: The likely mechanisms of stroke based on the infarct patterns at baseline in the 136 patients included in the study were artery-to-artery embolism (n = 69; 50.7%), perforator occlusion (n = 34; 25%), hypoperfusion (n = 12; 8.8%) and mixed (n = 21; 15.5%). Perforator-occlusive infarcts were more frequent in the posterior circulation, and mixed patterns were more prevalent in the anterior circulation (both p < 0.01). Most of the mixed patterns in the anterior circulation combined small pial or scattered multiple cortical infarcts with infarcts in border-zone regions, especially the cortical ones. Isolated border-zone infarcts were not significantly associated with a poor grading for collaterals or the severity of stenosis. Among 47 patients with a recurrent infarct during follow-up, the infarct patterns suggested an artery-to-artery embolic mechanism in 29 (61.7%). Conclusions: Artery-to-artery embolism is probably the most common mechanism of stroke in both the anterior and the posterior circulations in patients with ICAS. An extension of intracranial atherosclerosis at the site of stenosis into adjacent perforators also appears to be a common mechanism of stroke, particularly in the posterior circulation, whereas hypoperfusion as the sole mechanism is relatively uncommon. Further research is important to accurately establish the specific mechanisms of stroke in patients with ICAS, since preliminary data suggest that the underlying mechanism of stroke is an important determinant of prognosis.

Background and Purpose: Large-scale observational studies of acute ischemic stroke (AIS) promise to reveal mechanisms underlying cerebral ischemia. However, meaningful quantitative phenotypes attainable in large patient populations are needed. We characterize a dynamic metric of AIS instability, defined by change in National Institutes of Health Stroke Scale score (NIHSS) from baseline to 24 hours baseline to 24 hours (NIHSS _baseline – NIHSS _24hours = ΔNIHSS _6-24h ), to examine its relevance to AIS mechanisms and long-term outcomes. Methods: Patients with NIHSS prospectively recorded within 6 hours after onset and then 24 hours later were enrolled in the GENISIS study (Genetics of Early Neurological Instability After Ischemic Stroke). Stepwise linear regression determined variables that independently influenced ΔNIHSS _{6 –24h} . In a subcohort of tPA (alteplase)-treated patients with large vessel occlusion, the influence of early sustained recanalization and hemorrhagic transformation on ΔNIHSS _6–24h was examined. Finally, the association of ΔNIHSS _{6 –24h} with 90-day favorable outcomes (modified Rankin Scale score 0–2) was assessed. Independent analysis was performed using data from the 2 NINDS-tPA stroke trials (National Institute of Neurological Disorders and Stroke rt-PA). Results: For 2555 patients with AIS, median baseline NIHSS was 9 (interquartile range, 4–16), and median ΔNIHSS _{6 –24h} was 2 (interquartile range, 0–5). In a multivariable model, baseline NIHSS, tPA-treatment, age, glucose, site, and systolic blood pressure independently predicted ΔNIHSS _{6 –24h} (R ² =0.15). In the large vessel occlusion subcohort, early sustained recanalization and hemorrhagic transformation increased the explained variance (R ² =0.27), but much of the variance remained unexplained. ΔNIHSS _{6 –24h} had a significant and independent association with 90-day favorable outcome. For the subjects in the 2 NINDS-tPA trials, ΔNIHSS _{3 –24h} was similarly associated with 90-day outcomes. Conclusions: The dynamic phenotype, ΔNIHSS _6–24h , captures both explained and unexplained mechanisms involved in AIS and is significantly and independently associated with long-term outcomes. Thus, ΔNIHSS _{6 –24h} promises to be an easily obtainable and meaningful quantitative phenotype for large-scale genomic studies of AIS.

Background and Purpose: Improving prehospital triage of large vessel occlusion (LVO) would reduce time to reperfusion therapies. We aimed to study early predictors of LVO in acute ischemic stroke to identify candidates for endovascular treatment. Methods: The Stroke-Chip was a prospective observational study conducted at 6 Stroke Centers in Catalonia. Blood samples were obtained in the first 6 hours from symptom onset of consecutive patients. Stroke severity was evaluated with National Institutes of Health Stroke Scale (NIHSS) and LVO was assessed. Independent association of multiple blood biomarkers with LVO was evaluated using logistic regression models adjusted by covariates. Sensitivity, specificity, and predictive values were assessed for NIHSS and the combination of NIHSS and selected serum biomarkers levels. Results: One thousand three hundred eight suspected strokes were enrolled for a 17-month period. LVO was not assessed in 131 patients. One thousand one hundred seventy-seven patients were selected for analysis (mean age 69.3 years, 56% men, median baseline NIHSS of 6, and median time to blood collection 2.5 hours). LVO was detected in 262 patients. LVO patients were older, had higher baseline NIHSS, history of atrial fibrillation, and lower time from stroke onset to admission. After logistic regression analysis, D-dimer remained an independent predictor of LVO (odds ratio, 1.59 [1.31–1.92]). Specificity and positive predictive value to exclude or detect LVO were higher when using combined D-dimer levels and NIHSS score assessment rather than NIHSS alone. Conclusions: Early D-dimer levels are an independent predictor of LVO and may be useful to better optimize prehospital patient transport to the appropriate stroke center.

Objective: To investigate the effect of endovascular treatment on cognitive function as a prespecified secondary analysis of the REVASCAT (Endovascular Revascularization With Solitaire Device Versus Best Medical Therapy in Anterior Circulation Stroke Within 8 Hours) trial. Methods: REVASCAT randomized 206 patients with anterior circulation proximal arterial occlusion stroke to Solitaire thrombectomy or best medical treatment alone. Patients with established dementia were excluded from enrollment. Cognitive function was assessed in person with Trail Making Test (TMT) Parts A and B at 3 months and 1 year after randomization by an investigator masked to treatment allocation. Test completion within 5 minutes, time of completion (seconds), and number of errors were recorded. Results: From November 2012 to December 2014, 206 patients were enrolled in REVASCAT. TMT was assessed in 82 of 84 patients undergoing thrombectomy and 86 of 87 control patients alive at 3 months and in 71 of 79 patients undergoing thrombectomy and 72 of 78 control patients alive at 1 year. Rates of timely TMT-A completion were similar in both treatment arms, although patients undergoing thrombectomy required less time for TMT-A completion and had higher rates of error-free TMT-A performance. Thrombectomy was also associated with a higher probability of timely TMT-B completion (adjusted odds ratio 3.17, 95% confidence interval 1.51–6.66 at 3 months; and adjusted ratio 3.66, 95% confidence interval 1.60–8.35 at 1 year) and shorter time for TMT-B completion. Differences in TMT completion times between treatment arms were significant in patients with good functional outcome but not in those who were functionally dependent (modified Rankin Scale score >2). Poorer cognitive outcomes were significantly associated with larger infarct volume, higher modified Rankin Scale scores, and worse quality of life. Conclusions: Thrombectomy improves TMT performance after stroke, especially among patients who reach good functional recovery. ClinicalTrials.gov identifier: NCT01692379. Classification of evidence: This study provides Class I evidence that for patients with stroke from acute anterior circulation proximal arterial occlusion, thrombectomy improves performance on the TMT at 3 months.

Background: Although multiple studies and meta-analyses have consistently suggested that regular physical activity (PhA) is associated with a decreased stroke risk and recurrence, there is limited data on the possible preconditioning effect of prestroke PhA on stroke severity and prognosis. We aimed to study the association of prestroke PhA with different outcome variables in patients with acute ischemic stroke due to an anterior large vessel occlusion. Methods: The Prestroke Physical Activity and Functional Recovery in Patients with Ischemic Stroke and Arterial Occlusion trial is an observational and longitudinal study that included consecutive patients with acute ischemic stroke admitted to a single tertiary stroke center. Main inclusion criteria were: anterior circulation ischemic stroke within 12 h from symptom onset; presence of a confirmed anterior large vessel occlusion, and functional independence previous to stroke. Prestroke PhA was evaluated with the International Physical Activity Questionnaire and categorized into mild, moderate and high levels by means of metabolic equivalent (MET) minutes per week thresholds. The primary outcome measure was good functional outcome at 3 months (modified Rankin scale ≤2). Secondary outcomes were severity of stroke at admission, complete early recanalization, early dramatic neurological improvement and final infarct volume. Results: During the study period, 159 patients fulfilled the above criteria. The mean age was 68 years, 62% were men and the baseline NIHSS score was 17. Patients with high levels of prestroke PhA were younger, had more frequently distal occlusions and had lower levels of blood glucose and fibrinogen at admission. After multivariate analysis, a high level of prestroke PhA was associated with a good functional outcome at 3 months. Regarding secondary outcome variables and after adjustment for relevant factors, a high level of prestroke PhA was independently associated with milder stroke severity at admission, early dramatic improvement, early arterial recanalization after intravenous thrombolysis and lower final infarct volume. The beneficial association of prestroke PhA with stroke outcomes was already present with a cutoff point of 1,000 MET min/week, a level of PhA easily achieved by walking 1 h/day during 5 days or by doing a vigorous aerobic activity 1 h/day twice a week. Conclusions: Prestroke PhA is independently associated with favorable stroke outcomes after a large vessel occlusion. Future research on the underlying mechanisms is needed to understand this neuroprotective effect of PhA.