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BackgroundThe relationship between the interventionist’s experience and outcomes of endovascular thrombectomy (EVT) for acute ischemic stroke of the anterior circulation, is unclear.ObjectiveTo assess the effect of the interventionist’s level of experience on clinical, imaging, and workflow outcomes. Secondly, to determine which of the three experience definitions is most strongly associated with these outcome measures.MethodsWe analysed data from 2700 patients, included in the MR CLEAN Registry. We defined interventionist’s experience as the number of procedures performed in the year preceding the intervention (EXPfreq), total number of procedures performed (EXPno), and years of experience (EXPyears). Our outcomes were the baseline-adjusted National Institutes of Health Stroke Scale (NIHSS) score at 24–48 hours post-EVT, recanalization (extended Thrombolysis in Cerebral Infarction (eTICI) score ≥2B), and procedural duration. We used multilevel regression models with interventionists as random intercept. For EXPfreq and EXPno results were expressed per 10 procedures.ResultsIncreased EXPfreq was associated with lower 24–48 hour NIHSS scores (adjusted (a)β:−0.46, 95% CI −0.70 to −0.21). EXPno and EXPyears were not associated with short-term neurological outcomes. Increased EXPfreq and EXPno were both associated with recanalization (aOR=1.20, 95% CI 1.11 to 1.31 and aOR=1.08, 95% CI 1.04 to 1.12, respectively), and increased EXPfreq, EXPno, and EXPyears were all associated with shorter procedure times (aβ:−3.08, 95% CI−4.32 to −1.84; aβ:−1.34, 95% CI−1.84 to −0.85; and aβ:−0.79, 95% CI−1.45 to −0.13, respectively).ConclusionsHigher levels of interventionist’s experience are associated with better outcomes after EVT, in particular when experience is defined as the number of patients treated in the preceding year. Every 20 procedures more per year is associated with approximately one NIHSS score point decrease, an increased probability for recanalization (aOR=1.44), and a 6-minute shorter procedure time.

Background: Endovascular treatment (EVT) for acute ischemic stroke (AIS) is performed in intervention centers that provide the full range of neuro(endo)vascular care (level 1) and centers that only perform EVT for AIS (level 2). We compared outcomes between these center types and assessed whether differences in outcomes could be explained by center volume (CV). Patients and methods: We analyzed patients included in the MR CLEAN Registry (2014–2018), a registry of all EVT-treated patients in the Netherlands. Our primary outcome was the shift on the modified Rankin scale (mRS) after 90 days (ordinal regression). Secondary outcomes were the NIHSS 24–48 h post-EVT, door-to-groin time (DTGT), procedure time (linear regression), and recanalization (binary logistic regression). We compared outcomes between level 1 and 2 centers using multilevel regression models, with center as random intercept. We adjusted for relevant baseline factors, and in case of observed differences, we additionally adjusted for CV. Results: Of the 5144 patients 62% were treated in level 1 centers. We observed no significant differences between center types in mRS (adjusted(a)cOR: 0.79, 95% CI: 0.40 to 1.54), NIHSS (aβ: 0.31, 95% CI: −0.52 to 1.14), procedure duration (aβ: 0.88, 95% CI: −5.21 to 6.97), or DTGT (aβ: 4.24, 95% CI: −7.09 to 15.57). The probability for recanalization was higher in level 1 centers compared to level 2 centers (aOR 1.60, 95% CI: 1.10 to 2.33), and this difference probably depended on CV. Conclusions: We found no significant differences, that were independent of CV, in the outcomes of EVT for AIS between level 1 and level 2 intervention centers.

Background Insight into outcome variation between hospitals could help to improve quality of care. We aimed to assess the validity of early outcomes as quality indicators for acute ischemic stroke care for patients treated with endovascular therapy (EVT). Methods and Results We used data from the MR CLEAN (Multicenter Randomized Controlled Trial of Endovascular Treatment for Acute Ischemic Stroke in the Netherlands) Registry, a large multicenter prospective cohort study including 3279 patients with acute ischemic stroke undergoing EVT. Random effect linear and proportional odds regression were used to analyze the effect of case mix on between‐hospital differences in 2 early outcomes: the National Institutes of Health Stroke Scale (NIHSS) score at 24 to 48 hours and the expanded thrombolysis in cerebral infarction score. Between‐hospital variation in outcomes was assessed using the variance of random hospital effects (tau 2 ). In addition, we estimated the correlation between hospitals' EVT‐patient volume and (case‐mix–adjusted) outcomes. Both early outcomes and case‐mix characteristics varied significantly across hospitals. Between‐hospital variation in the expanded thrombolysis in cerebral infarction score was not influenced by case‐mix adjustment (tau 2 =0.17 in both models). In contrast, for the NIHSS score at 24 to 48 hours, case‐mix adjustment led to a decrease in variation between hospitals (tau 2 decreases from 0.19 to 0.17). Hospitals' EVT‐patient volume was strongly correlated with higher expanded thrombolysis in cerebral infarction scores ( r =0.48) and weakly with lower NIHSS score at 24 to 48 hours ( r =0.15). Conclusions Between‐hospital variation in NIHSS score at 24 to 48 hours is significantly influenced by case‐mix but not by patient volume. In contrast, between‐hospital variation in expanded thrombolysis in cerebral infarction score is strongly influenced by EVT‐patient volume but not by case‐mix. Both outcomes may be suitable for comparing hospitals on quality of care, provided that adequate adjustment for case‐mix is applied for NIHSS score.

BACKGROUND Both aspiration and stent retriever thrombectomy are safe and effective in patients with acute ischemic stroke due to large vessel occlusion in the anterior circulation. Little is known on the outcomes of these techniques in patients with basilar artery occlusion. This study aimed to compare clinical, technical, and safety outcomes of aspiration and stent retriever thrombectomy as first‐line treatment for basilar artery occlusion in the BASICS (Basilar artery International Cooperation Study) trial. METHODS For this post hoc analysis of the BASICS trial, all patients with a basilar artery occlusion who received endovascular treatment with either direct aspiration or stent retriever thrombectomy as first‐line approach were included. When both techniques were registered as first choice, patients were considered to have been treated with stent retriever. The primary outcome was favorable functional outcome, defined as a modified Rankin scale score of 0–3 at 90 days follow‐up, and analyzed using binary logistic regression analysis. Secondary outcomes included the modified Rankin scale score at 90 days (ranging from 0 to 6), procedure duration, mortality at 90 days, and symptomatic intracranial hemorrhage. Secondary outcomes were analyzed using binary, linear, or ordinal regression analyses. All analyses were adjusted for predefined variables. RESULTS Among 158 BASICS patients treated with endovascular treatment,127 were treated with either stent retriever (N=67, 53%), or aspiration (N=60, 47%) as the first‐line treatment modality. We observed no significant difference in favorable functional outcome between patients treated with aspiration and stent retriever thrombectomy as first modality (adjusted odds ratio, 1.80; [95% CI, 0.68–4.76]). Also modified Rankin scale score at 90 days (adjusted common odds ratio, 0.62; [95% CI, 0.30–1.27]) and incidence of symptomatic intracranial hemorrhage (adjusted odds ratio, 0.61; [95% CI, 0.08–4.76]) showed no significant differences between both techniques. Procedure time was shorter with a median of 32 versus 47 minutes (26%; 95% CI, −42 to −6) and mortality rates at 90 days were lower (adjusted odds ratio, 0.36; [95% CI: 0.13–1.00]) in the direct aspiration group. CONCLUSIONS This study shows no difference in favorable functional outcome in patients with a basilar artery occlusion treated with direct aspiration compared with patients treated with stent retriever thrombectomy within the BASICS trial, despite a shorter procedure time and lower mortality rate at 90 days.