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Background: Stroke caused by acute basilar artery occlusion (BAO) is devastating with high dependency and mortality. Recent trials have demonstrated the efficacy of endovascular treatment (EVT) for acute BAO, while pretreatment collaterals may be a valuable prognostic indicator for post-EVT outcomes. Aims: To systematically review and synthesize evidence on the associations between pretreatment collateral status and outcomes after EVT in acute BAO. Methods: We retrieved relevant full-text articles published in English since 1 January 2010, reporting associations between pretreatment collateral status and outcomes after EVT for BAO, by searching MEDLINE and Embase. The primary outcome was favorable or good 90-day functional outcome (modified Rankin Scale [mRS] 0–2 or 0–3); secondary outcomes included successful recanalization, symptomatic intracranial hemorrhage, final infarct volume, and 90-day mortality. Risk ratios (RRs) with 95% confidence intervals (CIs) for good versus poor collaterals on the outcomes were synthesized using random-effects models. Subgroup and sensitivity analyses were conducted for the primary outcome. Results: Overall, 29 primary studies (2995 participants) were included in qualitative review, among which 16 studies (1447 participants) were meta-analyzed. With different imaging modalities and methods to grade the collateral status, good collaterals were found in 33–85% of patients in the individual primary studies (I2 = 95.2%, p < 0.001), with a pooled proportion of 51% (95% CI: 40–62%) across all studies. Good pretreatment collaterals were associated with a doubled rate of favorable/good 90-day functional outcome (RR = 2.03, 95% CI: 1.63–2.51, p < 0.001), a higher rate of successful recanalization (RR = 1.23, 95% CI: 1.04–1.45, p = 0.015), and reduced 90-day mortality (RR = 0.59, 95% CI: 0.43–0.81, p = 0.001) after EVT for BAO. None of the primary studies reported the associations of good collaterals with the other secondary outcomes. Subgroup analyses revealed possibly more prominent protective effect of good pretreatment collaterals over the primary outcome, in studies with longer time windows in patient eligibility criteria for EVT (p = 0.028 for between-subgroup heterogeneity). Conclusions: In patients with BAO receiving EVT, good pretreatment collateral status was associated with a higher chance of favorable 90-day functional outcome, despite the various methods in grading the collateral circulation. Efforts are needed for more standardized collateral assessment in BAO, for more reliable and generalizable investigations of its clinical implications. [ABSTRACT FROM AUTHOR]

Background: Depicting the time trends of ischemic stroke subtypes may inform healthcare resource allocation on etiology-based stroke prevention and treatment. Aim: To reveal the evolving ischemic stroke subtypes from 2004 to 2018. Methods: We determined the stroke etiologies of consecutive first-ever transient ischemic attack or ischemic stroke patients admitted to a regional hospital in Hong Kong from 2004 to 2018. We analyzed the age-standardized incidences and the two-year recurrence rate of major ischemic stroke subtypes. Results: Among 6940 patients admitted from 2004 to 2018, age-standardized incidence of ischemic stroke declined from 187.0 to 127.4 per 100,000 population (p < 0.001), driven by the decrease in large artery disease (43.0–9.67 per 100,000 population (p < 0.001)), and small vessel disease (71.9–45.7 per 100,000 population (p < 0.001)). Age-standardized incidence of cardioembolic stroke did not change significantly (p = 0.2). Proportion of cardioembolic stroke increased from 20.4% in 2004–2006 to 29.3% in 2016–2018 (p < 0.001). Two-year recurrence rate of intracranial atherothrombotic stroke reduced from 19.3% to 5.1% (p < 0.001) with increased prescriptions of statin (p < 0.001) and dual antiplatelet therapy (p < 0.001). In parallel with increased anticoagulation use across the study period (p < 0.001), the two-year recurrence of AF-related stroke reduced from 18.9% to 6% (p < 0.001). Conclusion: Etiology-based risk factor control might have led to the diminishing stroke incidences related to atherosclerosis. To tackle the surge of AF-related strokes, arrhythmia screening, anticoagulation usage, and mechanical thrombectomy service should be reinforced. Comparable preventive strategies might alleviate the enormous stroke burden in mainland China. [ABSTRACT FROM AUTHOR]

We aimed to investigate the roles of antegrade residual flow and leptomeningeal collateral flow in sustaining cerebral perfusion distal to an intracranial atherosclerotic stenosis (ICAS). Patients with apparently normal cerebral perfusion distal to a symptomatic middle cerebral artery (MCA)-M1 stenosis were enrolled. Computational fluid dynamics models were built based on CT angiography to obtain a translesional pressure ratio (PR) to gauge the residual antegrade flow. Leptomeningeal collaterals (LMCs) were scaled on CT angiography. Cerebral perfusion metrics were obtained in CT perfusion maps. Among 83 patients, linear regression analyses revealed that both translesional PR and LMC scale were independently associated with relative ipsilesional mean transit time (rMTT). Subgroup analyses showed that ipsilesional rMTT was significantly associated with translesional PR (p < 0.001) rather than LMC scale in those with a moderate (50–69%) MCA stenosis, which, however, was only significantly associated with LMC scale (p = 0.051) in those with a severe (70–99%) stenosis. Antegrade residual flow and leptomeningeal collateral flow have complementary effects in sustaining cerebral perfusion distal to an ICAS, while cerebral perfusion may rely more on the collateral circulation in those with a severe stenosis. [ABSTRACT FROM AUTHOR]

A letter to the editor related to a study concerning the hemodynamic role and importance of intracranial arterial stenosis (ICAS) in diagnosing the risk of stroke in patients with symptomatic ICAS is presented.