Fusiform vertebrobasilar aneurysms (FVBAs) may exhibit a disastrous clinical course. Due to their rare occurrence, evidence concerning optimal management is lackluster. To describe the epidemiology, clinical features and treatment outcomes of a consecutive series of patients admitted to our institution. We retrospectively evaluated patient charts with respect to clinical presentation, treatment procedures, and the outcomes of all patients diagnosed with an FVBA, which were seen at our institution between March 2006 and February 2017. Forty-five consecutive patients were analyzed. Follow-up was available for 39 patients (86.7%) with a median duration of 28.8 months. Seventeen patients (37.7%) were asymptomatic, 14 patients (31.1%) presented with brainstem ischemia, 8 patients (17.8%) with supratentorial ischemia, and 3 (6.7%) patients with brain stem compression. Aneurysm rupture occurred in 3 patients upon presentation (6.7%). Initially, 19 patients (42.2%) were significantly disabled with Modified Rankin Scale (mRS) scores ≥ 3. Twelve patients (26.7%) underwent invasive treatment: endovascular therapy in 9 cases and surgical treatment in 3 cases. Thirty-three patients received conservative treatment. During follow-up, 6 events (66.7%) of severe disability or death (mRS 4–6) occurred in the endovascular group versus 1 event (33%) in the surgical group versus 19 events (63.3%) among conservatively treated aneurysms. Deterioration was significantly more frequent in patients with symptomatic aneurysms (p = 0.030). Patients harboring an FVBA frequently present with disabling symptoms caused by various pathomechanisms. The natural history is aggressive, mostly for initially symptomatic aneurysms, and periprocedural morbidity of surgical or endovascular treatment remains substantial.

Stent-retriever thrombectomy (SRT) for acute intracranial large artery occlusion (LAO) may not result in permanent recanalization in rare cases, e.g. due to an underlying stenosis or dissection. In this specific patient group, rescue stent angioplasty (RSA) may be the only treatment option to achieve permanent vessel patency and potentially a good clinical outcome. To date, the experience with RSA is limited.

The presence of high-frequency velocity fluctuations in aneurysms have been confirmed by in-vivo measurements and by several numerical simulation studies. Only a few studies have located and recorded wall vibrations in in-vitro experiments using physiological patient models. In this study, we investigated the wall fluctuations produced by a flowing perfusion fluid in a true-toscale elastic model of a cerebral fusiform aneurysm using a laser Doppler vibrometer (LDV). The model was obtained from patient data. The experimental setup reproduced physiologically relevant conditions using a compliant perfusion system, physiological flow parameters, unsteady flow and a non-Newtonian fluid. Three geometrically identical models with different wall elasticities were used for measurements. The influence of five different flow rates was considered. Wall vibrations were predominantly found at frequencies in the range 40-60 Hz and 255-265 Hz. Their amplitude increased with increasing elasticity of the model, but the spectral peaks remained at about the same frequency. Varying the flow rate produced almost no changes in the frequency domain of the models. The frequency of the spectral peaks varied slightly between points at the lateral wall and at the bottom of the aneurysm. Indeed, embedding the model in a fluid during measurements produced higher and smoother amplitude fluctuations.

The use of flow-diverters for non-saccular cerebral posterior circulation aneurysms requires complex deployment techniques and is associated with high mortality and morbidity. Therefore, further studies are required to clarify the effect of stenting on post-treatment hemodynamics in such aneurysms. In this study, we evaluated flow alterations in a treated giant fusiform aneurysm of the vertebrobasilar junction and correlated them with the clinical outcome. A patient-specific aneurysm model was acquired by rotational angiography, and three SILK flow-diverters (4.5 × 40, 5 × 40 and 5.5 × 40 mm) were virtually deployed in series along the basilar and right vertebral arteries. Image-based blood flow simulations before and after the treatment were performed under realistic pulsatile flow conditions. The flow reduction, velocity and wall shear stress (WSS) distribution, streamlines and WSS-derived parameters were evaluated before and after the treatment. The computed velocity streamlines showed substantial alterations of the flow pattern in the aneurysm and successful redirection of blood flow along the series of flow-diverters with no flow through the overlapping stents. The obtained flow reduction of 86% was sufficient to create thrombogenic flow conditions. Moreover, a 6.2-fold increase in relative residence time and a decrease by 87% of time-averaged WSS contributed to a successful treatment outcome observed during the follow-up. We found a correlation between the numerically predicted flow alterations and the available treatment outcome. This shows the potential of image-based simulations to be used in clinical practice for treatment planning and estimation of possible risk factors associated with a complex stent deployment in fusiform aneurysms of the posterior circulation.

Cerebral aneurysms are a major risk factor for intracranial bleeding with devastating consequences for the patient. One recently established treatment is the implantation of flow-diverters (FD). Methods to predict their treatment success before or directly after implantation are not well investigated yet. The aim of this work was to quantitatively study hemodynamic parameters in patient-specific models of treated cerebral aneurysms and its correlation with the clinical outcome. Hemodynamics were evaluated using both computational fluid dynamics (CFD) and phase contrast (PC) MRI. CFD simulations and in vitro MRI measurements were done under similar flow conditions and results of both methods were comparatively analyzed. For preoperative and postoperative distribution of hemodynamic parameters, CFD simulations and PC-MRI velocity measurements showed similar results. In both cases where no occlusion of the aneurysm was observed after six months, a flow reduction of about 30-50% was found, while in the clinically successful case with complete occlusion of the aneurysm after 6 months, the flow reduction was about 80%. No vortex was observed in any of the three models after treatment. The results are in agreement with recent studies suggesting that CFD simulations can predict post-treatment aneurysm flow alteration already before implantation of a FD and PC-MRI could validate the predicted hemodynamic changes right after implantation of a FD.

The majority of numerical simulations assumes blood as a Newtonian fluid due to an underestimation of the effect of non-Newtonian blood behavior on hemodynamics in the cerebral arteries. In the present study, we evaluated the effect of non-Newtonian blood properties on hemodynamics in the idealized 90[Formula: see text]-bifurcation model, using Newtonian and non-Newtonian fluids and different flow rate ratios between the parent artery and its branch. The proposed Local viscosity model was employed for high-precision representation of blood viscosity changes. The highest velocity differences were observed at zones with slow recirculating flow. During the systolic peak the average difference was 17–22%, whereas at the end of diastole the difference increased to 27–60% depending on the flow rate ratio. The main changes in the viscosity distribution were observed distal to the flow separation point, where the non-Newtonian fluid model produced 2.5 times higher viscosity. A presence of such high viscosity region substantially affected the size of the flow recirculation zone. The observed differences showed that non-Newtonian blood behavior had a significant effect on hemodynamic parameters and should be considered in the future studies of blood flow in cerebral arteries.

BACKGROUND: Flow diverter stents have become a useful tool for treatment of complex intracranial aneurysms. A serious complication is incomplete wall apposition after flow diverter placement. The aim of this study was to present a comprehensive investigation of hemodynamic changes induced by incomplete expansion of a flow diverter. METHODS: A case of a patient treated for an internal carotid artery aneurysm by flow diversion with incomplete wall apposition was virtually investigated. The effect of incomplete flow diverter expansion was studied using image-based blood flow simulations under physiologically relevant flow conditions based on patient-specific clinical data. RESULTS: The numerical results revealed that incomplete expansion at the proximal end of the stent had minimal impact on the intra-aneurysmal blood flow alteration. A region of nonphysiologically high wall shear stress was observed near the contact area between the incompletely expanded proximal end of the flow diverter and the parent artery, which caused an intimal hyperplasia in this region. These simulation results were consistent with the real-life clinical course and outcome. CONCLUSIONS: The results of this study can be considered during treatment planning of complex cases where the risk of incomplete flow diverter expansion exists. Further studies are required before results can also be used to support the decision process about antiplatelet therapy and additional interventions to improve wall apposition.

Flow changes after flow diverter (FD) placement may be assessed by 4D phase-contrast MR-angiography (4D flow MRI) or simulated by computational fluid dynamics (CFD). However, cross-validation and future assessments with both approaches to take advantage of their individual strengths are required. In this study, we investigate the influence of a FD on intra-aneurysmal blood flow using both MRI experiments and CFD simulations. MR measurements were performed in a true-to-scale silicone model of a wide-neck saccular aneurysm of the distal internal carotid artery before and after FD deployment. An experimental setup, including a computer-controlled piston pump, was assembled to simulate pulsatile blood flow. For CFD studies, a virtual stenting technique was used to place a FD into the aneurysm model. Boundary conditions were applied according to MRI-measured flow data. A qualitative and quantitative agreement of velocity fields measured by CFD and MRI both before and after FD placement was demonstrated. The intra-aneurysmal flow reduction in the CFD results was 19%, while a reduction of 23% was measured by 4D flow MRI. Despite of the low spatial resolution, MRI was able to correctly determine the flow pattern in the aneurysm. The pre-treatment CFD simulation could be helpful in predicting the outcome of a FD treatment, while a post-interventional MRI could prove the desired treatment effect.

The aim of our study was the technical evaluation of a first pass approach of primary thrombus aspiration (AST) in patients with emergency large intracerebral vessel occlusions (ELVO) under routine clinical conditions.

Purpose The aim of this study was to compare the rates of intraprocedural thrombus fragmentation between the exclusive thrombus aspiration technique (ADAPT) and the use of stent retrievers.Materials and Methods Cases with successful recanalization of the primary occlusion site (POS) with either of the techniques were analyzed (n = 36 ADAPT, n = 61 stent retriever). The primary endpoint was the evaluation of intraprocedural thrombus fragmentation before applying additional maneuvers to enhance reperfusion success. Grading was performed using the modified thrombolysis in cerebral infarction (mTICI) perfusion scale grade with the implementation of an additional TICI 2c grade. Secondary endpoints were procedural complications and clinical data.Results After opening of the POS, 83.3% successful reperfusions were reached using the ADAPT technique and 88.5% using stent retrievers (p = 0.47). Subarachnoid hemorrhages (SAH) appeared only when using stent retrievers (16.4 vs. 0%, p = 0.010). The number of maneuvers was significantly higher (median 2 vs. 1, p = 0.006), and procedural time was longer in the stent retriever group (median 30 vs. 13 min, p < 0.0001). There was no significant difference between both techniques with regard to the occurrence of embolizations to new territories (2.8 vs. 8.2%, p = 0.28).Conclusion When retrieving of the primary thrombus is possible, ADAPT results in comparable reperfusion grades as do stent retrievers. This suggests that comparable distraction forces act on the thrombus and that both techniques possess a comparable risk of periprocedural thrombus fragmentation. SAH exclusively occurred after using stent retrievers, which may further promote ADAPT as safe and fast initial front-line approach.

OBJECTIVE:Especially since the establishment of mechanical thrombectomy as part of standard stroke therapy, artificial thrombi have become important in the training of interventionalists as well as for the development and testing of devices. So far, these in vitro clots have lacked direct comparisons with ex vivo thrombi. We therefore compared the histologic appearance of dynamically produced clots with that of stroke thrombi acquired during mechanical recanalization. METHODS:Thrombi of 145 consecutive patients with stroke with large-vessel occlusions were histologically compared with 10 artificial clots, dynamically created from human blood and pig's blood using a Chandler loop system. Quantified FP/RBC ratios (fibrin/platelets divided by red blood cell fraction) and white blood cell (WBC) fractions were identified and compared between artificial (human and pig) and ex vivo thrombi obtained from patients with various stroke causes. RESULTS:There were no significant differences in the analysis of FP/RBC ratios between artificial thrombi and ex vivo thrombi (P = 0.42) or in the more precise analyses considering etiologic subgroups. Distinct differences were observed for the WBC fraction, with lower values in artificial thrombi (median, 1.34%) than in ex vivo thrombi (median, 5%) (P < 0.001). CONCLUSIONS:The main clot components, FP and RBC, are presumably the most influential factors for clot stability and mechanical resistance. Similarities between artificially generated and ex vivo stroke clots (and when considering different stroke subgroups) support the usefulness of these artificial thrombi in the pre-evaluation of thrombus extraction devices and as appropriate training material.

Background: This study aimed to analyze the effects of technical outcome of mechanical thrombectomy (MTE) on the associations between collateral status, assessed with pretreatment computed tomography angiography (CTA), and neurological and functional outcome, as well as associations between collaterals and metabolic risk factors (arterial hypertension, diabetes, hyperlipidemia, overweight). Methods: Prospectively collected data of 115 patients with CTA-proven isolated middle cerebral artery occlusion treated successfully with MTE (Thrombosis in Cerebral Infarction [TICI] scale 2b or 3) were assessed retrospectively. Initial CTAs were assessed for the regional leptomeningeal collateralization score (rLMC), neurological status was determined with the National Institutes of Health Stroke Scale (NIHSS) at admission and discharge, and mid-term functional outcome was assessed using the modified Rankin scale (mRS) 90 days after MTE. Results: NIHSS score at admission was significantly associated with rLMC (P = .004), whereas rLMC and NIHSS at discharge showed no significant associations (P = .12). Better rLMC was significantly associated with improved mid-term mRS (P = .018). This association was even more significant after complete MTE (TICI 3; P = .011). Arterial hypertension was significantly more often found in patients with poor rLMC (010) than in patients with good rLMC (11-20; P = .046), yet other risk factors showed no significant associations (P > .05). Conclusions: In patients with successful MTE, good collaterals were associated with better neurological status at admission and favorable mid-term functional outcome. In patients with complete MTE, associations were even more significant compared with those with "almost complete" MTE, suggesting a synergistic effect between good collaterals and complete MTE and a predictive value of collaterals for estimation of the potential clinical benefit of MTE.

Anterior spinal artery syndrome (ASAS) often leads to complete motor paralysis with poor clinical outcome. There is a lack of controlled clinical trials on acute treatment strategies in ASAS. However, systemic thrombolysis with recombinant tissue-plasminogen activator (rt-PA) might be a useful therapeutic option in ASAS. We report the management of a patient with ASAS below thoracic level 10, who was treated with intravenous thrombolysis. An 81 year old patient presented with flaccid paraplegia. After exclusion of aortal dissection, spinal tumour or haemorrhage, the patient was treated with intravenous rt-PA 3 h 40 min after symptom onset. The follow up magnetic resonance imaging (MRI) showed spinal infarction below thoracic segment 10. In the clinical course, the patient partially recovered lower limb muscle strength and was able to walk with assistance. To the best of our knowledge, this is the first case in the literature of ASAS with MRI-proven spinal ischemia and the application of rt-PA. Systemic thrombolysis seems to be justifiable in patients with ASAS after the rule-out of aortal dissection and spinal bleeding.

ObjectivesAcute Recanalization of Thrombo-Embolic Ischemic Stroke with pREset (ARTESp) is a prospective multicenter study assessing the efficacy and safety of the pREset stent retriever for the treatment of intracranial vessel occlusion. Determination of the effect of transfer status on clinical outcome was a secondary objective.MethodsEfficacy was measured by recanalization success (Thrombolysis in Cerebral Infarction score ≥2b) and favorable clinical outcome at 90 days (modified Rankin Scale 0–2). Intracranial hemorrhage (ICH) and death at 90 days were safety measures. The outcome of directly admitted (DAP) and transferred (TP) patients was investigated using multivariable regression models.ResultsFour study centers included 100 patients (mean age 68.3 years, median National Institutes of Health Stroke Scale score 15). Recanalization success was achieved in 84.4% after a mean of 1.7 passes. ICH was detected in 14.0%, with 2.0% being symptomatic. At 90 days, 62.5% of the patients had a favorable outcome and 7.3% died. TP had longer occlusion times (289 vs 180 minutes, p<0.001) and a lower rate of favorable outcome (58.0% vs 78.4%, p=0.046) than DAP. Multivariable regression revealed occlusion time as the critical determinant (OR=0.963, 95% CI 0.931 to 0.997, p=0.032), whereas transfer status itself showed no significant association (OR=0.565, CI 0.133 to 2.393, p=0.438).ConclusionspREset proved to be safe and effective for the treatment of acute intracranial vessel occlusion. Increased occlusion time impaired clinical outcome in TP.Trial registration numberNCT02437409; Results.

Background and purpose Mechanical endovascular therapy (MET) is a promising adjuvant or stand-alone therapy for acute ischaemic stroke caused by occlusion of a large vessel. Real-time monitoring of recanalisation success with regard to functional outcome is usually not possible because these procedures are mainly performed under general anaesthesia. We present a novel application for evoked potential monitoring for real-time evaluation of reperfusion success with respect to functional outcome during MET for acute ischaemic stroke.Methods Prospective observational study from March 2012 to April 2013 of patients presenting with acute ischaemic stroke who were eligible for MET. Transcranial motor evoked potentials (MEPs) and somatosensory evoked potentials (SSEPs) were measured bilaterally during MET throughout the intervention. The electrophysiological data of the contralateral side served as control. Neurological outcome was assessed by the modified Rankin Scale and National Institutes of Health Stroke Scale at 0, 7 and 90 days following intervention.Results 20 patients were examined. MEPs and SSEPs were technically successful in 19 (95%) and 9 (45%) cases, respectively. Successful reperfusion was achieved in 16 cases. Functional recovery was observed in 14 patients. MEPs and SSEPs recovery status was a better predictor of functional recovery than successful reperfusion with a positive predictive value of 92%, 83% and 75% for MEPs, SSEPs and reperfusion, respectively.Conclusions MEPs and SSEPs are safe and feasible methods of real-time monitoring of reperfusion success with respect to functional outcome during MET for acute ischaemic stroke.

BACKGROUND:Stent-assisted coil embolization (SACE) plays an important role in the treatment of intracranial aneurysms. The purpose of this study was to investigate geometrical changes caused by closed-cell design stents in bifurcation and sidewall aneurysms.METHODS:31 patients with 34 aneurysms underwent SACE with closed-cell design stents. Inflow angle α, determined by aneurysm neck and afferent vessel, and angle between afferent and efferent vessel close to (δ1), respectively, more remote from the aneurysm neck (δ2) were graphically determined in 2D angiography projections.RESULTS:Stent assisted coiling resulted in a significant increase of all three angles from a mean value (±SEM) of α = 119° (±6.5°) pretreatment to 130° (±6.6°) posttreatment (P ≤ .001), δ1 = 129° (±6.4°) to 139° (±6.1°), (P ≤ .001) and δ2 = 115° (±8.4°) to 126° (±7.5°), (P ≤ .01). Angular change of δ1 in AcomA aneurysms was significant greater compared to sidewall aneurysms (26°±4.9° versus 8°± 2.3°, P ≤ .05). The initial angle of δ1 and δ2 revealed a significantly inverse relationship to the angle increase (δ1: r = -0.41, P ≤ .05 and δ2: r = -0.47, P ≤ .01). Moreover, angle δ1 was significantly higher in unruptured compared to ruptured aneurysms (135°±7.1° versus 103°±10.8°, P ≤ .05).CONCLUSION:Stent deployment modulates the geometry of the aneurysm-vessel complex, which may lead to favorable hemodynamic changes more similar to unruptured than to ruptured aneurysms. Our findings also suggest that the more acute-angled aneurysm-vessel anatomy, the larger the angular change. Further studies are needed to investigate whether these changes improve the clinical outcome.

Aktuelle Studien zur mechanischen Rekanalisation beim akuten ischämischen Schlaganfall weisen darauf hin, dass eine primäre Aspirationsthrombektomie mit hohen Rekanalisationsraten und kurzer Prozedurdauer assoziiert ist. Ziel dieser Studie ist die technische Evaluation der primären Aspirationsthrombektomie unter klinischen Alltagsbedingungen.

Objective: We present our clinical experience of surgical flow diversion including extra-intracranial bypass surgery and vertebral artery occlusion as an alternative treatment in otherwise untreatable complex vertebrobasilar and posterior artery aneurysms.

Background Stroke in aged patients has a relatively poor prognosis, even after recanalizing therapy. Potential reasons include mechanisms that relate directly to the extent of brain tissue damage, but also age-dependent factors which are not, or only indirectly, stroke-related, such as pre-existing functional deficits, comorbidities, and post-stroke complications (eg, infections).Objective To compare early neurological course with subsequent functional outcome in older (>= 80 years) and younger stroke patients in order to estimate the relative impact of these factors. Specifically, to examine if the strong age-dependency of modified Rankin Scale (mRS) outcome scores in stroke patients after mechanical thrombectomy is paralleled by a similar age dependency of early postinterventional National Institute of Health Stroke Scale (NIHSS) scores-a more specific measure of stroke-induced brain damage.Methods We evaluated technical results, pre-and postinterventional NIHSS scores, mid-term mRS scores and early and overall mortality and their relation to age in 125 patients, 40 of them >= 80 years, with acute middle cerebral artery occlusion, treated by mechanical thrombectomy.Results Technical success, pre-and postinterventional NIHSS scores and early mortality were age-independent. Early neurological improvement depended on successful recanalization, but not on age. Nevertheless, good mRS outcome (mRS 0-2) was much rarer, and overall mortality almost threefold higher in aged patients.Conclusions Older patients exhibit a similar early neurological course and responsiveness to mechanical thrombectomy as younger patients, but this is not reflected in mid-term functional outcome scores. This indicates that post-stroke complications and other factors that are not, or only indirectly, related to the brain tissue damage induced by the incident stroke have a dominant role in their poor prognosis.

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