Deep-Learning-Based Thrombus Localization and Segmentation in Patients with Posterior Circulation Stroke.

Thrombus volume in posterior circulation stroke (PCS) has been associated with outcome, through recanalization. Manual thrombus segmentation is impractical for large scale analysis of image characteristics. Hence, in this study we develop the first automatic method for thrombus localization and segmentation on CT in patients with PCS. In this multi-center retrospective study, 187 patients with PCS from the MR CLEAN Registry were included. We developed a convolutional neural network (CNN) that segments thrombi and restricts the volume-of-interest (VOI) to the brainstem (Polar-UNet). Furthermore, we reduced false positive localization by removing small-volume objects, referred to as volume-based removal (VBR). Polar-UNet is benchmarked against a CNN that does not restrict the VOI (BL-UNet). Performance metrics included the intra-class correlation coefficient (ICC) between automated and manually segmented thrombus volumes, the thrombus localization precision and recall, and the Dice coefficient. The majority of the thrombi were localized. Without VBR, Polar-UNet achieved a thrombus localization recall of 0.82, versus 0.78 achieved by BL-UNet. This high recall was accompanied by a low precision of 0.14 and 0.09. VBR improved precision to 0.65 and 0.56 for Polar-UNet and BL-UNet, respectively, with a small reduction in recall to 0.75 and 0.69. The Dice coefficient achieved by Polar-UNet was 0.44, versus 0.38 achieved by BL-UNet with VBR. Both methods achieved ICCs of 0.41 (95% CI: 0.27-0.54). Restricting the VOI to the brainstem improved the thrombus localization precision, recall, and segmentation overlap compared to the benchmark. VBR improved thrombus localization precision but lowered recall.

Etiology of Large Vessel Occlusion Posterior Circulation Stroke: Results of the MR CLEAN Registry.

BACKGROUND: In patients with large vessel occlusion stroke of the anterior circulation, underlying cause is a determinant of outcome. Whether this is the case for posterior circulation large vessel occlusion stroke has yet to be determined. We aimed to report on cause in patients with posterior circulation stroke treated with endovascular thrombectomy and to analyze the association with functional outcome. METHODS: We used data of patients with posterior circulation stroke included in the MR CLEAN (Multicenter Randomized Controlled Trial of Endovascular Treatment for Acute Ischemic Stroke in the Netherlands) registry, a prospective multicenter observational study, between 2014 and 2018. Stroke cause was categorized into large artery atherosclerosis (LAA), cardioembolism, arterial dissection, embolic stroke of undetermined source (ESUS), other determined cause, or undetermined cause. For primary analysis on the association between cause and outcome, we used multivariable ordinal logistic regression analysis to estimate the adjusted common odds ratio for a shift towards a better functional outcome on the modified Rankin Scale at 90 days with LAA as a reference group. Secondary outcomes included favorable functional outcome (modified Rankin Scale score 0-3), National Institutes of Health Stroke Scale score at 24 to 48 hours, reperfusion on digital subtraction angiography, and stroke progression. RESULTS: Of 264 patients with posterior circulation stroke, 84 (32%) had LAA, 48 (18%) cardioembolism, 31 (12%) dissection, and 14 (5%) ESUS. Patients with a dissection were younger (48 [interquartile range, 43-60] years) and had a lower National Institutes of Health Stroke Scale at baseline (12 [interquartile range, 6-31]) than patients with other cause. Functional outcome was better for patients with cardioembolism and ESUS compared to LAA (modified Rankin Scale adjusted common odds ratio, 2.4 [95% CI, 1.1-5.2], respectively adjusted common odds ratio, 3.1 [95% CI, 1.0-9.3]). Patients with a dissection had a lower chance of successful reperfusion compared with LAA (adjusted odds ratio, 0.20 [95% CI, 0.06-0.70]). CONCLUSIONS: Unlike the anterior circulation, most frequent cause in our posterior large vessel occlusion stroke cohort is LAA followed by cardioembolism, dissection, and ESUS. Patients with cardioembolism and ESUS have a better prognosis for functional outcome after endovascular thrombectomy than patients with LAA.

Endovascular Treatment for Posterior Circulation Stroke in Routine Clinical Practice: Results of the Multicenter Randomized Clinical Trial of Endovascular Treatment for Acute Ischemic Stroke in the Netherlands Registry.

BACKGROUND AND PURPOSE: The benefit of endovascular treatment (EVT) for posterior circulation stroke (PCS) remains uncertain, and little is known on treatment outcomes in clinical practice. This study evaluates outcomes of a large PCS cohort treated with EVT in clinical practice. Simultaneous to this observational study, several intervention centers participated in the BASICS trial (Basilar Artery International Cooperation Study), which tested the efficacy of EVT for basilar artery occlusion in a randomized setting. We additionally compared characteristics and outcomes of patients treated outside BASICS in trial centers to those from nontrial centers. METHODS: We included patients with PCS from the Multicenter Randomized Clinical Trial of Endovascular Treatment for Acute Ischemic Stroke in the Netherlands Registry: a prospective, multicenter, observational study of patients who underwent EVT in the Netherlands between 2014 and 2018. Primary outcome was a score of 0 to 3 on the modified Rankin Scale at 90 days. Secondary outcomes included reperfusion status and symptomatic intracranial hemorrhage. For outcome comparison between patients treated in trial versus nontrial centers, we used ordinal logistic regression analysis. RESULTS: We included 264 patients of whom 135 (51%) had received intravenous thrombolysis. The basilar artery was most often involved (77%). Favorable outcome (modified Rankin Scale score 0-3) was observed in 115/252 (46%) patients, and 109/252 (43%) patients died. Successful reperfusion was achieved in 178/238 (75%), and symptomatic intracranial hemorrhage occurred in 9/264 (3%). The 154 nontrial patients receiving EVT in BASICS trial centers had similar characteristics and outcomes as the 110 patients treated in nontrial centers (modified Rankin Scale adjusted cOR: 0.77 [95% CI, 0.5-1.2]). CONCLUSIONS: Our study shows that high rates of favorable clinical outcome and successful reperfusion can be achieved with EVT for PCS, despite high mortality. Characteristics and outcomes of patients treated in trial versus nontrial centers were similar indicating that our cohort is representative of clinical practice in the Netherlands. Randomized studies using modern treatment approaches are needed for further insight in the benefit of EVT for PCS.

[Endovascular arteriovenous fistulas: percutaneous creation of vascular access for hemodialysis]. / Endovasculair aangelegde arterioveneuze fistels.

A novel endovascular technique allows percutaneous creation of arteriovenous fistulas for hemodialysis. The proximal radial artery is cannulated through the perforating vein in the cubital fossa using ultrasound guidance. A fused anastomosis between these blood vessels is created using heat and pressure. This results in an arteriovenous fistula that can be regarded as an alternative for a surgically created brachiocephalic fistula. In our early experience, this new technique is safe and successful. Moreover, no complications due to high-flow fistulas have been reported with this technique to date. Nevertheless, the intervention rate and the cost effectiveness of the new endovascular technique need to be compared to traditional open surgery before it can be considered standard clinical care.

A Technical Report on the Performance of a New Large Bore Cerebral Aspiration Catheter, the First Results.

AIMS AND BACKGROUND: We describe the initial results of the Syphontrack Super Distal Access (SDA) catheter (InNeuroco Inc., Sunrise, Fl, USA) used for endovascular treatment of patients with acute ischemic stroke of the anterior circulation. METHODS: A retrospective review of prospectively collected data from June 2017 to May 2018 in Maastricht University Medical Center plus (MUMC +) with direct distal aspiration or a combination of distal aspiration with stent retriever thrombectomy was performed. Primary outcome measurements were accessibility and reperfusion grade (eTICI). Secondary outcome measurements were early neurologic recovery (a decrease of four or more points on the NIHSS), symptomatic intracranial hemorrhage (sICH) within 24 h and mRS score at 3 months. RESULTS: The first 50 patients in whom the SDA catheter was used are included. Direct distal aspiration was performed in 33/50 (66%). In 29/33 (88%), distal position in contact with the clot was achieved of which 15 (52%) were successful (eTICI 2b or higher) after first attempt. Total successful reperfusion rate was 23/50 (46%) after first pass. Final successful reperfusion, after multiple attempts, was reached in 48/50 (96%). Early neurologic recovery was seen in 21/50 (42%), and functional independence (mRS score of 0-2) at 3 months was achieved in 17/50 (35%). sICH occurred in 4/50 (8%) within 24 h post-procedural. CONCLUSION: In our clinical practice, endovascular treatment of ischemic stroke with the SDA catheter had similar technical and clinical results as reported in the literature.