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Background: Acute ischemic stroke with large or medium-vessel occlusion associated with intracranial artery calcification (IAC) is an infrequent phenomenon presumably associated with intracranial atherosclerotic disease. We aimed to characterize IAC and its impact on endovascular treatment outcomes. Methods: We performed a retrospective cross-sectional study of consecutive patients with stroke treated with thrombectomy from January 2020 to July 2021 in our institution. We described IAC findings (length, density, and location pattern) on baseline noncontrast computed tomography. Patients were divided into 3 groups: IAC related to the occlusion location (symptomatic-IAC group), unrelated to the occlusion (asymptomatic-IAC group), and absence of any IAC (non-IAC group). We analyzed the association between the IAC profile and outcomes using logistic regression models. Intracranial angioplasty and stenting were considered rescue treatments. Results: Of the 393 patients included, 26 (6.6%) patients presented a symptomatic-IAC, 77 (19.6%) patients an asymptomatic-IAC, and in 290 (73.8%) patients no IAC was observed. The rate of failed recanalization (expanded Thrombolysis in Cerebral Infarction 0-2a) before rescue treatment was higher in symptomatic-IAC (65.4%) than in asymptomatic-IAC (15.6%; P P P P P P =0.004), and poor functional outcome (90-day modified Rankin Scale score ≥3; odds ratio, 3.51 [95% CI, 1.02–12.00]; P =0.046). Conclusions: The presence of IAC related to the occlusion location is associated with worse angiographic and functional outcomes. Therefore, identification of symptomatic-IAC on baseline imaging may guide optimal endovascular treatment strategy, predicting the need for intracranial stenting and angioplasty.

Hypothesis: We aim to identify a profile of intracranial thrombus resistant to recanalization by standard mechanical thrombectomy (MT) in acute stroke treatment. Methods: First extracted clot of each MT were analyzed by Flow Cytometry obtaining composition of main leukocyte populations: granulocytes, monocytes and lymphocytes. Demographics, reperfusion treatment and grade of recanalization were registered. MT Failure ( MTF) was defined as final Thrombolysis in Cerebral Infarction score IIa or lower and/ or need of permanent intracranial stenting as a rescue therapy after standard MT. In other cohort of cases, unconfined compression tests were performed to explore stiffness of retrieved clots . We looked for correlation between mechanical characterization tests and clot composition. Results: Among 225 patients, there were 13 % of MTF that were significantly associated to atherosclerosis etiology ( 33.3% vs. 15.9% ; p 0.021) , more passes ( 3 vs. 2; p Conclusions: There is a positive correlation between granulocyte proportion and thrombi stiffness that may explain endovascular resistance to recanalization. Influence of granulocytes within thrombus may be a target for future reperfusion treatments.

Background: Increasing efficacy of endovascular thrombectomy for ischemic stroke entails a rising demand for intervention outside Comprehensive Stroke Centers (CSC), in regions where time to treatment and transfer delays result in worse outcomes. We explore the use of a remote teleproctoring system to support vascular interventionists in a remote Local Stroke Center (LSC) to safely perform mechanical thrombectomy (MT) in patients with acute ischemic stroke. Methods: Since November 2020, a Tegus Medical Teleproctoring System was installed in a LSC (Arnau de Vilanova Hospital, Lleida) where the potential MT population could be 80-100 procedures/year, however only half that figure is currently being treated, with most patients transferred to the CSC (Vall d’Hebron Hospital, Barcelona) 160 kms away. Since the implementation of this technology, thrombectomy procedures have been performed by vascular interventionists with moderate neurovascular experience at the LSC, remotely assisted by expert neurointerventionists from the CSC. We retrospectively analyzed the safety and effectiveness of MT with the aid of this proctoring System, comparing with procedures performed in the CSC. Results: Ten MT were performed in the LSC, comprising 50% of the acute stroke cases taken to the angiosuite in one year. The thrombectomy technique was combined distal aspiration with stent-retriever in all cases. Seven thrombectomies resulted successful after the first pass (70%), achieving complete/near complete recanalization (TICI 2c/3) in 80% of the cases. Comparing with CSC, median puncture to recanalization time was 31 (26-62) vs 42 (27-67) and the rate of final succesful reperfusion (90% in LSC vs 86.5% in CSC) was similar. No technical or procedural complications were reported. At 90 days, 40% of the patients had a mRS 0-2. A survey exploring the personal experience showed that communication was considered optimal and confidence in decision making was considered high at both ends of the system. Conclusion: Tegus system seems a valuable tool to support vascular interventionists facing a rise in thrombectomy demands in distant LSCs maintaining enough safety, effectiveness and confidence during the procedures. These data should be challenged by prospective studies.

Background: Endovascular treatment (EVT) for acute ischemic stroke (AIS) between 6 to 24 hours is established as a standard of care among patients selected by multiparametric neuroimaging. Therefore, we aimed to explore neuroimaging parameters in late window AIS large vessel occlusion (LVO) patients and the association between findings in non-contrast computed tomography (NCCT) and multiparametric CT. Methods: We included consecutive AIS patients within 6-24 hours from symptoms onset with CTA-LVO. We studied potential associations between computed tomography mismatch defined by DAWN and/or DEFUSE-3 neuroimaging criteria (CTP-MM), infarct volume on CTP, and ASPECTS on NCCT. We also analyzed the association between neuroimaging parameters and outcome determined by 90-day mRS. Results: We included 206 patients, of which 176 (85.4%) presented CTP-MM and 184 (89.3%) presented with an ASPECTS ≥ 6 on admission. The rate of CTP-MM was 90.8% in patients with ASPECTS ≥ 6, as compared with 40.9% in those with low ASPECTS [Figure 1A] . The ASPECTS correlated with infarct core, determined by Cerebral Blood Flow [Figure 1B] . Conclusions: A great majority of patients who presented a LVO in late window fulfilled guidelines imaging criteria to undergo EVT, especially those with high ASPECTS (≥ 6). Our data suggest that NCCT with CT angiography is a reasonable approach for acute ischemic stroke treatment selection also in the late window.

Artificial Intelligence (AI) can assist in vessel occlusion (VO) identification in acute stroke patients. We aim to investigate the impact of using an AI-based software for automated VO detection on non-contrast CT (AI-VO) as compared to CT-Aangiograpphy (CTA). Methods: From April to October 2020 all patients admitted with a suspected acute ischemic stroke underwent urgent non-contrast CT / CTA / CTP and were treated accordingly. Hypoperfusion areas defined as Tmax>6s on CTP (RAPID software), congruent with the clinical symptoms and a vascular territory, were considered VO (CTP-VO: ground truth). In addition, two experienced neuroradiologists blinded to CTP but not to clinical symptoms retrospectively evaluated CT and CTA to identify intracranial VO (CTA-VO). AI-VO was automatically determined by an AI-based software (Methinks). Results: Of the 338 patients included, 157 (46.5%) showed a CTP-VO (median Tmax>6s: 73[29-127]ml). Overall sensitivity to detect CTP-VO was 50.3% for CTA-VO and 66.9% for AI-VO; specificity was 97.8% for CTA-VO and 86.2% for AI-VO. EVT was performed in 103 patients (EVT-VO: 65.6% of CTP-VO; Tmax>6s: 102[63-160]ml); sensitivity to detect EVT-VO was 69% for CTA-VO and 79.6% for AI-VO; specificity was 95.3% for CTA-VO and 79.6% for AI-VO. The probability to detect a CTP-VO was higher with AI than with CTA for distal occlusions (figure). Accordingly, AI-VO sensitivity was higher than CTA-VO for angiographically confirmed M2/M3-MCA occlusions (80.7% vs 34.6%; p=0.002) but not for M1-MCA/ICA occlusions (82.1% Vs 88.1%;p=0.467). Conclusion: AI-assisted vessel occlusion identification on non-contrast CT may be a useful tool in acute stroke evaluation, especially for distal VO identification, potentially increasing endovascular treatment in these cases.