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BackgroundTandem occlusions cause 10–15% of LVO acute ischemic strokes but are difficult to treat endovascularly and frequently excluded from clinical trials. The optimum endovascular method is still debated, however going directly through the carotid occlusion can speed up the procedure and reduce procedural risk by eliminating an exchange maneuver.MethodUsing retrospective data from three centers, we compared treating atherosclerotic tandem occlusions using a 0.035'-guidewire and direct dotterisation or angioplasty with a peripheral vascular balloon suitable for the wire, vs. the usual technique of an 0.014'wire. We compared the successful recanalization (mTICI 2b-3) rates, 90 days' functional outcomes (mRS 0–2), and puncture-to-recanalization times between both procedures.ResultsForty-two consecutive patients with atherosclerotic tandem occlusions were included; 25 were treated with the 0.014'wire technique and 17 with the 0.035'-guidewire and direct dotterisation or angioplasty with a peripheral vascular balloon technique. The direct technique achieved a higher rate of successful recanalization (100 vs. 72%, P = 0.018), better functional outcome (88.4 vs. 48.0%, P = 0.044), and faster procedure times (mean 65.1 mins vs. 114.8 mins, P < 0.001). The number of attempts was similar between both groups (median 2 vs 3 attempts, P = 0.101). There was no significant difference in the complication rate between both groups (5.9 vs. 12.0%, P = 0.462).ConclusionCompared to previous endovascular techniques for treating atherosclerotic tandem occlusions, the direct technique using standard 0.035' guidewires and dotterisation or a peripheral vascular balloon is significantly faster with better outcomes. However, this will require further external validation in larger cohorts.

Deep cerebral venous thrombosis (CVT) is an uncommon condition with a high morbidity and mortality. The optimal treatment approach for deep CVT remains uncertain and due to its low prevalence, randomized trials are not feasible. We showcase a straight sinus thrombosis treated with a large bore aspiration and performed a meta-analysis of the available literature to characterize and evaluate the various treatment modalities for patients with deep CVT. We conducted a systematic search in PubMed, EMBASE and Ovid Medline using appropriate keywords/MESH terms search strategy. All patients with thrombosis involving the deep venous sinuses were included if treatment records were available. Outcome measures included recanalization of the affected sinus, good functional outcome assessed by a modified Rankin scale (mRS) of 0–2 or reported independent functional outcomes, permanent neurological deficits, further hemorrhage and mortality. A total of 69 studies comprising 120 patients were included in the analysis. Anticoagulation was the most common treatment (85.8%), whilst local intrasinus thrombolysis was performed in 40.0% of the patients and mechanical endovascular modalities were employed in 20.0% of the patients. Recanalization of the occluded sinus was seen in 83.5% of the patients while 62.6% patients achieved good functional outcome. There was considerable morbidity with 60.7% having a permanent neurological deficit, 23.3% having further hemorrhage after admission and 18.6% mortality. In the cohort receiving anticoagulation, 65.3% achieved good outcome but intracranial hemorrhage at presentation was associated with poorer outcome, permanent deficits, further bleeding and mortality. Anticoagulation is an effective treatment strategy for deep CVT; however, patients with intracranial hemorrhage at presentation often have poorer outcomes and early endovascular strategies could be considered in this subgroup.

Background and aim Bi-directional feedback mechanisms exist between the heart and brain, which have been implicated in heart failure. We postulate that aortic stenosis may alter cerebral haemodynamics and influence functional outcomes after endovascular thrombectomy for acute ischaemic stroke. We compared clinical characteristics, echocardiographic profile and outcomes in patients with or without aortic stenosis that underwent endovascular thrombectomy for large vessel occlusion acute ischaemic stroke. Methods Consecutive acute ischaemic stroke patients with anterior and posterior circulation large vessel occlusion (internal carotid artery, middle cerebral artery and basilar artery) who underwent endovascular thrombectomy were studied. Patients were divided into those with significant aortic stenosis (aortic valve area 2) and without. Univariate and multivariate analyses were employed to compare and determine predictors of functional outcomes measured by modified Rankin scale at three months. Results We identified 26 (8.5%) patients with significant aortic stenosis. These patients were older (median age 76 (interquartile range 68–84) vs. 67 (interquartile range 56–75) years, p = 0.001), but similar in terms of medical comorbidities and echocardiographic profile. Rates of successful recanalisation (73.1% vs. 78.0%), symptomatic intracranial haemorrhage (7.7% and 7.9%) and mortality (11.5% vs. 12.6%) were similar. Significant aortic stenosis was independently associated with poorer functional outcome (modified Rankin scale >2) at three months (adjusted odds ratio 2.7, 95% confidence interval 1.1–7.5, p = 0.048), after adjusting for age, door-to-puncture times, stroke severity and rates of successful recanalisation. Conclusion In acute ischaemic stroke patients managed with endovascular thrombectomy, significant aortic stenosis is associated with poor functional outcome despite comparable recanalisation rates. Larger cohort studies are needed to explore this relationship further.

BACKGROUND AND PURPOSE: Mechanical thrombectomy (MT) is an effective treatment for patients with basilar artery occlusion (BAO) acute ischemic stroke. It remains unclear whether bridging intravenous thrombolysis (IVT) prior to MT confers any benefit. This study compared the outcomes of acute BAO patients who were treated with direct MT versus combined IVT plus MT. METHODS: This multicenter retrospective cohort study included patients who were treated for acute BAO from eight comprehensive stroke centers between January 2015 and December 2019. Patients received direct MT or combined bridging IVT plus MT. Primary outcome was favorable functional outcome defined as modified Rankin Scale 0-3 measured at 90 days. Secondary outcome measures included mortality and symptomatic intracranial hemorrhage (sICH). RESULTS: Among 322 patients, 127 (39.4%) patients underwent bridging IVT followed by MT and 195 (60.6%) underwent direct MT. The mean±standard deviation age was 67.5±14.1 years, 64.0% were male and median National Institutes of Health Stroke Scale was 16 (interquartile range, 8 to 25). At 90-day, the rate of favorable functional outcome was similar between the bridging IVT and direct MT groups (39.4% vs. 34.4%, P=0.361). On multivariable analyses, bridging IVT was not as Comorbidisociated with favorable functional outcome, mortality or sICH. In subgroup analyses, patients with underlying atherosclerosis treated with bridging IVT compared to direct MT had a higher rate of favorable functional outcome at 90 days (37.2% vs. 15.5%, P=0.013). CONCLUSIONS: Functional outcomes were similar in BAO patients treated with bridging IVT versus direct MT. In the subgroup of patients with underlying large-artery atherosclerosis stroke mechanism, bridging IVT may potentially confer benefit and this warrants further investigation.

Purpose: Modelling blood flow in cerebral arteries presents an opportunity to go beyond current luminal stenosis. These models could improve stroke prognostication by adding hemodynamic biomarkers such as translesional shear stress and pressure gradient. Such models, however, are rarely validated against real clinical data. We evaluated the accuracy of a computational fluid dynamics (CFD) model which uses allometric scaling laws against population-based Phase Contrast MRI (PC-MRI) measurements of blood flow in the brain. Methods: 3D models of the anterior circulation of 23 healthy subjects were reconstructed based on their MRA Time of Flight (TOF) images and CFD was used for modelling the blood flow. Lumped parameter Windkessel models were used as boundary conditions and allometric scaling laws were used to divide the flow and tune these boundary conditions, i.e. the resistance at each boundary was automatically adjusted based on the dimensions and branching of upstream vasculature. The results were compared against 4 PC-MRI studies from literature, covering a combined number of 417 healthy subjects. Results: The flow rate across 3 major intracranial arteries (ICA, MCA, and ACA) was obtained from the CFD simulations and was in good agreement with population-based PC-MRI studies. The agreement was 82.6% for the ICA, 85.9% for the MCA, and 80.4% for the ACA when comparing the average flow rate. The inter-patient variability of the flow rate (i.e. standard deviation) obtained from CFD simulations matched closely with the variation range measured in the literature. Allometric scaling enabled the model to accurately divide the flow at bifurcations (MCA/ICA flow ratio was 58.6% for the model vs 56.3% in the literature). We observed an average of 8 mmHg in pressure drop along the anterior circulation of healthy subjects (from ICA to MCA-M1 and ACA-A1), which agrees with the physiological range reported in the literature. Conclusion: This study shows the potential of accurately modelling blood flow based only on static images and demonstrates the validity of using allometric scaling in intracranial CFD simulations. The current modelling approach can potentially assist in stroke prognostication by obtaining hemodynamic risk factors from standard MRA TOF or CTA.

Studies have shown that the modified thrombolysis in cerebral ischemia (mTICI) 2B score is associated with better functional outcome; however, 50–99% reperfusion is a large range and there may be factors which can differentiate this further. The effects of very late leptomeningeal collaterals (VLLC) on mTICI-2B patients were studied. A prospectively collected registry of anterior circulation AIS patients treated with the EmboTrap revascularization device from 2013 to 2016 was evaluated. Imaging parameters and timings, including the mTICI score were verified by an external core laboratory blinded to the clinical data. The final angiogram was examined for the appearance of VLLC in predicting 3‑month outcomes including excellent functional outcomes, defined as modified Rankin scale (mRS) 0–1, bleeding risk and mortality. A total of 177 consecutive anterior circulation stroke patients were included in the analysis. Of these 94 (53.1%) achieved only mTICI-2B reperfusion, 16/94 (17.0%) patients achieved excellent functional outcomes at 3 months and 26 (27.7%) had hyperdensity on follow-up computed tomography (CT). On univariate analysis, the presence of VLLC was inversely associated with excellent functional outcomes at 3 months and positively associated with mortality in patients with mTICI-2B reperfusion. On multivariate analysis VLLC was inversely associated with excellent outcomes (odds ratio 0.075, 95% confidence interval 0.007–0.765, P = 0.029) but not associated with mortality. The mTICI-2B grade may be further refined by secondary radiological markers. The VLLC sign is associated with the loss of excellent functional outcomes at 3 months. It is a simple sign to discriminate mTICI-2B into different grades but should be verified in larger populations from other centers.

Background Collateral blood flow is known to be an important factor that sustains the penumbra during acute stroke. We looked at both the leptomeningeal collateral circulation and the presence of anterior and posterior communicating arteries to determine the factors associated with good outcomes and mortality. Methods We included all patients with acute ischaemic stroke in the anterior circulation, who underwent thrombectomy with the same thrombectomy device from 2013 to 2016. We assessed the leptomeningeal circulation by the Tan, Miteff and Maas validated scoring systems on pre-treatment computed tomographic angiography scans and looked at collateral flow through anterior and posterior communicating arteries. The results were good functional outcomes at 3 months (modified Rankin scale 0–2) and mortality. Results A total of 147 consecutive acute stroke patients treated with the Embotrap device were included with a median National Institutes of Health stroke scale of 15 (range 2–26). On multivariate analysis only younger age (odds ratio (OR) 0.96/year, 95% confidence interval (CI) 0.94–0.99, P = 0.026), lower National Institutes of Health stroke scale score (OR 0.87/point, 95% CI 0.80–0.93, P Conclusions Our study shows that the presence of anterior and posterior communicating arteries is significantly associated with good functional outcomes and reduced mortality, respectively, independent of the leptomeningeal circulation status.

Thrombectomy is a technique that has completely changed the management of acute stroke and current devices have shown that they can achieve upwards of 90% successful recanalization in selected cohorts. However, despite the effectiveness of these devices, there are a proportion of patients who still fail to achieve reperfusion of the affected vascular territory and an even larger portion of patients who have poor functional outcomes in spite of successful recanalization. There are no guidelines on how to treat these patients when such failures occur. In an effort to understand the underpinnings of how failed thrombectomy occurs, we extensively reviewed the current literature in clot properties, vascular access problems, stroke pathogenic mechanisms, embolic complications, failed procedures and pre-procedural imaging. A short summary of each of these contentious areas are provided and the current state of the art. Together these elements give a cohesive overview of the mechanisms of failed thrombectomy as well as the controversies facing the field. New techniques and devices can then be developed to minimize such factors during stroke thrombectomy.

Studies have shown that the modified thrombolysis in cerebral ischemia (mTICI) 2B score is associated with better functional outcome; however, 50-99% reperfusion is a large range and there may be factors which can differentiate this further. The effects of very late leptomeningeal collaterals (VLLC) on mTICI-2B patients were studied.A prospectively collected registry of anterior circulation AIS patients treated with the EmboTrap revascularization device from 2013 to 2016 was evaluated. Imaging parameters and timings, including the mTICI score were verified by an external core laboratory blinded to the clinical data. The final angiogram was examined for the appearance of VLLC in predicting 3‑month outcomes including excellent functional outcomes, defined as modified Rankin scale (mRS) 0-1, bleeding risk and mortality.A total of 177 consecutive anterior circulation stroke patients were included in the analysis. Of these 94 (53.1%) achieved only mTICI-2B reperfusion, 16/94 (17.0%) patients achieved excellent functional outcomes at 3 months and 26 (27.7%) had hyperdensity on follow-up computed tomography (CT). On univariate analysis, the presence of VLLC was inversely associated with excellent functional outcomes at 3 months and positively associated with mortality in patients with mTICI-2B reperfusion. On multivariate analysis VLLC was inversely associated with excellent outcomes (odds ratio 0.075, 95% confidence interval 0.007-0.765, P = 0.029) but not associated with mortality.The mTICI-2B grade may be further refined by secondary radiological markers. The VLLC sign is associated with the loss of excellent functional outcomes at 3 months. It is a simple sign to discriminate mTICI-2B into different grades but should be verified in larger populations from other centers.

The nutcracker syndrome is a rare clinical manifestation of symptoms caused by the compression of the left renal vein by an overriding superior mesenteric artery, an anatomical variant otherwise known as the nutcracker phenomenon. Usually present in women and children, when symptomatic, it commonly presents with hematuria, proteinuria, and chronic pelvic pain. Effective modalities of treatment apart from conservative management, include both invasive surgical procedures such as renal vein transposition and autotransplantation of the kidney and more popular recently, the less invasive endovascular stenting. Both options, however, are not without complications, such as, retroperitoneal hematomas or stent migration, thrombosis and restenosis. We now present a case of spontaneous renosplenic shunting in a 68-year-old lady of Chinese descent with the nutcracker syndrome—the first of such cases to be ever reported in a patient with no preexisting predilection for chronic liver disease and portosystemic shunting. Despite having significant pelvic venous congestion as evident on computed tomography scans, she remained asymptomatic. This may present a novel paradigm shift for the treatment of the nutcracker syndrome —surgical creation of a renosplenic bypass instead of current modalities, an alternative solution which can be performed laparoscopically and is without problems related to stent use. The creation of laparoscopic splenorenal bypass has been reported once thus far in Cleveland Ohio by Chung and Gill with good symptomatic improvement but no further studies since to validate its long-term effectiveness.