BACKGROUND AND PURPOSE: Successful vessel recanalization in posterior circulation large-vessel occlusion is considered crucial, though the evidence of clinical usefulness, compared with the anterior circulation, is not still determined. The aim of this study was to evaluate predictors of favorable clinical outcome and to analyze the effect of first-pass thrombectomy. MATERIALS AND METHODS:A retrospective, multicenter, observational study was conducted in 10 high-volume stroke centers in Europe, including the period from January 2016 to July 2019. Only patients with an acute basilar artery occlusion or a single, dominant vertebral artery occlusion ("functional" basilar artery occlusion) who had a 3-month mRS were included. Clinical, procedural, and radiologic data were evaluated, and the association between these parameters and both the functional outcome and the firstpass effect was assessed.RESULTS: A total of 191 patients were included. A lower baseline NIHSS score (adjusted OR, 0.77; 95% CI, 0.61-0.96; P ¼ .025) and higher baseline MR imaging posterior circulation ASPECTS (adjusted OR, 3.01; 95% CI, 1.03-8.76; P ¼ .043) were predictors of better outcomes. The use of large-bore catheters (adjusted OR, 2.25; 95% CI, 1.08-4.67; P ¼ .030) was a positive predictor of successful reperfusion at firstpass, while the use of a combined technique was a negative predictor (adjusted OR, 0.26; 95% CI, 0.09-0.76; P ¼ .014). CONCLUSIONS:The analysis of our retrospective series demonstrates that a lower baseline NIHSS score and a higher MR imaging posterior circulation ASPECTS were predictors of good clinical outcome. The use of large-bore catheters was a positive predictor of first-pass modified TICI 2b/3; the use of a combined technique was a negative predictor.ABBREVIATIONS: BAO ¼ basilar artery occlusion; F-P mTICI ¼ first-pass effect mTICI; IQR ¼ interquartile range; mTICI ¼ modified TICI; pc-ASPECTS ¼ posterior circulation ASPECTS; pc-LVO ¼ large-vessel occlusion of the posterior circulation P osterior circulation stroke accounts for about 20% of all ischemic stroke cases. 1,2 The etiology is variable (thromboembolic, atherosclerosis, arterial dissection, perforating vessels disease, and so forth), affecting different vascular territories; rarely, this type of stroke is due to a large-vessel occlusion of the posterior circulation (pc-LVO), representing about 1% of all acute ischemic strokes, 3,4 Acute pc-LVO carries a high risk of disabling stroke or death. In this context, designing a randomized controlled trial is challenging, and even appropriate patient selection is problematic. Successful vessel recanalization is considered crucial for survival or for improving functional outcome, 5,6 though the evidence of the clinical usefulness of endovascular

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Background and Purpose— As a reliable scoring system to detect the risk of symptomatic intracerebral hemorrhage after thrombectomy for ischemic stroke is not yet available, we developed a nomogram for predicting symptomatic intracerebral hemorrhage in patients with large vessel occlusion in the anterior circulation who received bridging of thrombectomy with intravenous thrombolysis (training set), and to validate the model by using a cohort of patients treated with direct thrombectomy (test set). Methods— We conducted a cohort study on prospectively collected data from 3714 patients enrolled in the IER (Italian Registry of Endovascular Stroke Treatment in Acute Stroke). Symptomatic intracerebral hemorrhage was defined as any type of intracerebral hemorrhage with increase of ≥4 National Institutes of Health Stroke Scale score points from baseline ≤24 hours or death. Based on multivariate logistic models, the nomogram was generated. We assessed the discriminative performance by using the area under the receiver operating characteristic curve. Results— National Institutes of Health Stroke Scale score, onset-to-end procedure time, age, unsuccessful recanalization, and Careggi collateral score composed the IER-SICH nomogram. After removing Careggi collateral score from the first model, a second model including Alberta Stroke Program Early CT Score was developed. The area under the receiver operating characteristic curve of the IER-SICH nomogram was 0.778 in the training set (n=492) and 0.709 in the test set (n=399). The area under the receiver operating characteristic curve of the second model was 0.733 in the training set (n=988) and 0.685 in the test set (n=779). Conclusions— The IER-SICH nomogram is the first model developed and validated for predicting symptomatic intracerebral hemorrhage after thrombectomy. It may provide indications on early identification of patients for more or less postprocedural intensive management.

Background There are limited data concerning procedure-related complications of endovascular thrombectomy for large vessel occlusion strokes. Aims We evaluated the cumulative incidence, the clinical relevance in terms of increased disability and mortality, and risk factors for complications. Methods From January 2011 to December 2017, 4799 patients were enrolled by 36 centers in the Italian Registry of Endovascular Stroke Treatment. Data on demographic and procedural characteristics, complications, and clinical outcome at three months were prospectively collected. Results The complications cumulative incidence was 201 per 1000 patients undergoing endovascular thrombectomy. Ongoing antiplatelet therapy (p < 0.01; OR 1.82, 95% CI: 1.21–2.73) and large vessel occlusion site (carotid-T, p < 0.03; OR 3.05, 95% CI: 1.13–8.19; M2-segment-MCA, p < 0.01; OR 4.54, 95% CI: 1.66–12.44) were associated with a higher risk of subarachnoid hemorrhage/arterial perforation. Thrombectomy alone (p < 0.01; OR 0.50, 95% CI: 0.31–0.83) and younger age (p < 0.04; OR 0.98, 95% CI: 0.97–0.99) revealed a lower risk of developing dissection. M2-segment-MCA occlusion (p < 0.01; OR 0.35, 95% CI: 0.19–0.64) and hypertension (p < 0.04; OR 0.77, 95% CI: 0.6–0.98) were less related to clot embolization. Higher NIHSS at onset (p < 0.01; OR 1.04, 95% CI: 1.02–1.06), longer groin-to-reperfusion time (p < 0.01; OR 1.05, 95% CI: 1.02–1.07), diabetes (p < 0.01; OR 1.67, 95% CI: 1.25–2.23), and LVO site (carotid-T, p < 0.01; OR 1.96, 95% CI: 1.26–3.05; M2-segment-MCA, p < 0.02; OR 1.62, 95% CI: 1.08–2.42) were associated with a higher risk of developing symptomatic intracerebral hemorrhage compared to no/asymptomatic intracerebral hemorrhage. The subgroup of patients treated with thrombectomy alone presented a lower risk of symptomatic intracerebral hemorrhage (p < 0.01; OR 0.70; 95% CI: 0.55–0.90). Subarachnoid hemorrhage/arterial perforation and symptomatic intracerebral hemorrhage after endovascular thrombectomy worsen both functional independence and mortality at three-month follow-up (p < 0.01). Distal embolization is associated with neurological deterioration (p < 0.01), while arterial dissection did not affect clinical outcome at follow-up. Conclusions Complications globally considered are not uncommon and may result in poor clinical outcome. Early recognition of risk factors might help to prevent complications and manage them appropriately in order to maximize endovascular thrombectomy benefits.

Objectives To retrospectively analyze interventional radiology (IR) activity changes in the COVID-19 era and to describe how to safely and effectively reorganize IR activity. Methods All IR procedures performed between January 30 and April 8, 2020 (COVID-era group) and the same 2019 period (non-COVID-era group) were retrospectively included and compared. A sub-analysis for the lockdown period (LDP: 11 March-8 April) was also conducted. Demographic, hospitalization, clinical, and procedural data were obtained for both groups and statistically compared with univariable analysis. Results A total of 1496 procedures (non-COVID era, 825; COVID era, 671) performed in 1226 patients (64.9 ± 15.1 years, 618 women) were included. The number of procedures decreased by 18.6% between 2019 and 2020 (825 vs 671, p < .001), with a reduction by 48.2% in LDP (188 vs 363, p < .0001). In the LDP COVID era, bedside procedures were preferred (p = .013), with an increase in procedures from the intensive care unit compared with the emergency department and outpatients (p = .048), and an increased activity for oncological patients (p = .003). No incidents of cross-infection of non-infected from infected patients and no evidence of COVID-19 infection of healthcare workers in the IR service was registered. Conclusions Coronavirus disease outbreak changed the interventional radiology activity with an overall reduction in the number of procedures. However, this study confirms that interventional radiology continuum of care can be safely performed also during the pandemic, following defined measures and protocols, taking care of all patients. Key Points • Coronavirus disease pandemic determined a reduction of interventional radiology activity as compared to the same period of the previous year. • Interventional radiology procedures for life-threatening conditions and non-deferrable oncologic treatments were prioritized as opposed to elective procedures. • Strict adoption of safe procedures allowed us to have until now no incidents of cross-infection of non-infected from infected patients and no evidence of COVID-19 infection of HCWs in the IR service.

Background and PurposeThe benefit of mechanical thrombectomy (MT) in patients with acute ischemic stroke (AIS) due to large vessel occlusion (LVO) and baseline mild neurological symptoms remains unclear. The purpose of this study was to evaluate the effectiveness of MT in this subgroup of patients. Methods The databases of 9 high-volume Italian stroke centers were retrospectively screened for patients with LVO in the anterior circulation and a baseline National Institute of Health Stroke Scale (NIHSS) score ≤ 5 that received either immediate MT or best medical management (BMM) with the possibility of rescue MT upon neurological worsening. Primary outcome measure was a modified Rankin Scale score of 0-1 at 90 days. Propensity score matching (PSM) analysis was used to estimate the treatment effect of immediate MT compared to BMM/rescue MT. Results Two hundred and seventy-two patients received immediate MT (MT group). The BMM/rescue MT group included 41 patients. The primary outcome was achieved in 78.6% (n = 246) of overall patients, with a higher proportion in the MT group (80.5% vs. 65.9%, p = 0.03) in unadjusted analysis. After PSM, patients in the MT group had a 19.5% higher chance of excellent outcome at 90 days compared to the BMM/Rescue MT group with a similar risk of death from any cause. Conclusions Our experience is in favor of a potential benefit of MT also in patients with LVO and a NIHSS score ≤ 5 at the time of groin puncture. Nonetheless, this issue waits for a clear-cut recommendation in a dedicated clinical trial.

BackgroundM2 segment occlusions represent approximately one-third of non-lacunar ischemic stroke and can lead to permanent neurological deficits. Various techniques are available for mechanical thrombectomy beyond the circle of Willis, but data evaluating their effectiveness and safety are lacking.MethodsA retrospective review of patients with ischemic stroke undergoing mechanical thrombectomy for M2 occlusions from 13 centers in North American and Europe was performed. Tandem or multiple-territory occlusions were excluded. The primary outcome was 90-day modified Rankin Scale and reperfusion rates across stent-retriever, direct aspiration and combined techniques.ResultsThere were 465 patients (mean age 71.48±14.03 years, 53.1% female) with M2 occlusions who underwent mechanical thrombectomy. Stent-retriever alone was used in 133 (28.6%), direct aspiration alone in 93 (20.0%) and the combined technique in 239 (51.4%) patients. Successful reperfusion was achieved with the combined technique in 198 (82.2%; OR 2.6 (1.1–6.9)), with stent-retriever alone in 112 (84.2%; OR 9.2 (1.9–44.6)) and with direct aspiration alone in 62 (66.7%; referencecategory). Intraprocedural subarachnoid hemorrhages (iSAH) were 36 (7.7%) and were more likely to occur in patients treated with the stent-retrievers (OR 5.0 (1.1–24.3)) and combined technique (OR 4.6 (1.1–20.9)). Good clinical outcome was achieved in 260 (61.8%) patients, while 59 (14.0%) patients died. Older age, higher baseline NIHSS (National Institutes of Health Stroke Scale), parenchymal hemorrhage and iSAH were associated with poor outcome while successful recanalization and higher baseline ASPECTS (Alberta Stroke Program Early CT Score) were associated with good outcome. No differences were found among the three techniques in terms of clinical outcome.ConclusionStent-retrievers and a combined approach for M2 occlusions seem more effective than direct aspiration, but with higher rates of iSAH. This leads to no detectable difference in clinical outcome at 3 months.

Background Endovascular therapy with liquid embolic agents (LEAs) is the gold standard for the treatment of cerebral dural arteriovenous fistulas (cDAVFs). The aim of the study is to retrospectively evaluate effectiveness, safety, and midterm follow-up results of endovascular treatment of cDAVFs using SQUID 12. Methods Between June 2017 and January 2020 the authors retrospectively reviewed clinical, demographic and embolization data of 19 consecutive patients with cDAVF who underwent embolization using SQUID 12. The number of arteries catheterized for each procedure, the total amount of embolic agent, the occlusion rate, the injection time, any technical and/or clinical complications were recorded. Mid-term follow-up with DSA was reviewed. Results 20 procedures were performed in 19 patients. A transarterial approach was accomplished in 19 procedure; a combined transvenous-transarterial approach was realized in 1 treatment. The average time of injection was 33 minutes (2–82 minutes), and the average amount of SQUID 12 was 2.8 mL (0.5–6 mL). Complete angiographic cure at the end of the procedure was achieved in 17 patients. No major periprocedural adverse events were recorded. Mid-term follow-up was achieved in 15 out of 19 patients and confirmed complete occlusion of the cDAVFs in 13/15 patients (87%); in 2 of the initially cured patients a small relapse was detected. Conclusions The treatment of the cDAVFs using SQUID 12 was effective and safe. The lower viscosity seems to allow an easier penetration of the agent with a high rate of complete occlusion of the cDAVFs.