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115 result(s) for "Flottmann, Fabian"
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Predictors of poor clinical outcome despite complete reperfusion in acute ischemic stroke patients
BackgroundIn patients suffering from acute ischemic stroke from large vessel occlusion (LVO), mechanical thrombectomy (MT) often leads to successful reperfusion. Only approximately half of these patients have a favorable clinical outcome. Our aim was to determine the prognostic factors associated with poor clinical outcome following complete reperfusion.MethodsPatients treated with MT for LVO from a prospective single-center stroke registry between July 2015 and April 2019 were screened. Complete reperfusion was defined as Thrombolysis in Cerebral Infarction (TICI) grade 3. A modified Rankin scale at 90 days (mRS90) of 3–6 was defined as ‘poor outcome’. A logistic regression analysis was performed with poor outcome as a dependent variable, and baseline clinical data, comorbidities, stroke severity, collateral status, and treatment information as independent variables.Results123 patients with complete reperfusion (TICI 3) were included in this study. Poor clinical outcome was observed in 67 (54.5%) of these patients. Multivariable logistic regression analysis identified greater age (adjusted OR 1.10, 95% CI 1.04 to 1.17; p=0.001), higher admission National Institutes of Health Stroke Scale (NIHSS) (OR 1.14, 95% CI 1.02 to 1.28; p=0.024), and lower Alberta Stroke Program Early CT Score (ASPECTS) (OR 0.6, 95% CI 0.4 to 0.84; p=0.007) as independent predictors of poor outcome. Poor outcome was independent of collateral score.ConclusionPoor clinical outcome is observed in a large proportion of acute ischemic stroke patients treated with MT, despite complete reperfusion. In this study, futile recanalization was shown to occur independently of collateral status, but was associated with increasing age and stroke severity.
Vessel diameter and catheter-to-vessel ratio affect the success rate of clot aspiration
BackgroundA direct aspiration first pass technique (ADAPT) is an efficient, safe, cost-effective, and fast thrombectomy technique.ObjectiveTo evaluate anatomical and clot characteristics associated with success of the aspiration component as part of ADAPT.Methods106 cases of acute carotid-T, basilar, and middle cerebral artery occlusion undergoing endovascular treatment with ADAPT were retrospectively assessed for successful catheter-clot contact and successful primary aspiration, defined as a Thrombolysis in Cerebral Infarction score ≥2b after primary aspiration with 5F or 6F aspiration catheters. Patient age, National Institutes of Health Stroke Scale (NIHSS) score, time from symptom onset to groin puncture, time from groin puncture to revascularization, aortic arch type, access vessel tortuosity, vessel diameter at the proximal end of the thrombus, catheter-to-vessel ratio (CVR), clot density, length, and perviousness were determined.ResultsSuccessful clot contact with the aspiration catheter was achieved in 76 cases (72%); these patients were younger (67.7±15.2 vs 73.7±11.4 years; p=0.05) and had less tortuous access vessels (1 vs 2 reverse curves; p=0.004) than those in whom clot contact failed. Successful primary aspiration occurred in 36 of these cases (47%) and was associated with significantly smaller vessel diameter at the proximal thrombus end (2.5±0.7 mm vs 3.1±1.3 mm; p=0.01) and higher CVR (CVR outer diameter: 0.85±0.2 vs 0.68±0.2; p=0.01 and CVR inner diameter: 0.72±0.2 vs 0.58±0.2; p<0.001). No significant differences were seen in aortic arch type, radiographic clot features, and NIHSS score.ConclusionWith ADAPT, patient age and vessel tortuosity affect the ability to deliver the aspiration catheter and achieve clot contact, whereas vessel diameter and CVR at the aspiration site seem to affect the effectiveness of clot aspiration. Strategies aimed at improving catheter deliverability and increasing CVR may increase the efficacy of ADAPT.
First experience with Walrus balloon guide catheter in a whole-body flow model
Purpose Flow arrest using a balloon guide catheter (BGC) in mechanical thrombectomy (MT) due to large vessel occlusion has been associated with better outcomes. Known limitations of currently commercially available BGCs are incompatibility with large bore aspiration catheters (AC) and lack of distal flexibility. Walrus presents variable stiffness and compatibility with large bore AC. The goal of this study is to describe the first experience with Walrus in a realistic stroke simulation model. Methods A full-length modular vascular model under physiological conditions was used. 8F + -Walrus inner-diameter (ID) 0.087in 95 cm combined with 6F-Sofia AC ID 0.070in 131 cm and an 8F-Flowgate2 BGC ID 0.084in 95 cm with a 5F-Sofia AC ID 0.055in 125 cm were used to perform aspiration MT. User surveys, access to target and occlusion site, technique, time of delivery, anatomical change, and catheter kick-back were assessed. Results Seven neuroradiologists with average of 10 years-experience in MT performed primary aspiration using the above-mentioned combinations in three different anatomies ( N  = 41). All operators would likely (29%) or very likely (71%) use again Walrus in combination with large bore AC and the majority (86%) found its navigability easier than with other BGCs. Time to reach final BGC position and catheter kick-back did not differ significantly among anatomies or catheter combinations ( p  > 0.05). However, Walrus was more likely to reach ICA petrous segment ( p  < 0.05) and intracranial occlusion with AC ( p  < 0.01). Conclusion The Walrus combined with large bore AC presented significantly better distal access and navigability for primary aspiration in an in vitro stroke model.
Elevated blood glucose is associated with aggravated brain edema in acute stroke
Background and purpose Clinical outcome after endovascular thrombectomy in patients with acute ischemic stroke still varies significantly. Higher blood glucose levels (BGL) have been associated with worse clinical outcome, but the pathophysiological causes are not yet understood. We hypothesized that higher levels of BGL are associated with more pronounced ischemic brain edema and worse clinical outcome mediated by cerebral collateral circulation. Methods 178 acute ischemic stroke patients who underwent mechanical thrombectomy were included. Early ischemic brain edema was determined using quantitative lesion water uptake on initial computed tomography (CT) and collateral status was assessed with an established 5-point scoring system in CT-angiography. Good clinical outcome was defined as functional independence (modified Rankin Scale [mRS] score 0–2). Multivariable logistic regression analysis was performed to predict functional independence and linear regression analyses to investigate the impact of BGL and collateral status on water uptake. Results The mean BGL at admission was significantly lower in patients with good outcome at 90 days (116.5 versus 138.5 mg/dl; p  < 0.001) and early water uptake was lower (6.3% versus 9.6%; p  < 0.001). The likelihood for good outcome declined with increasing BGL (odds ratio [OR] per 100 mg/dl BGL increase: 0.15; 95% CI 0.02–0.86; p  = 0.039). Worse collaterals (1% water uptake per point, 95% CI 0.4–1.7%) and higher BGL (0.6% per 10 mg/dl BGL, 95% CI 0.3–0.8%) were significantly associated with increased water uptake. Conclusion Elevated admission BGL were associated with increased early brain edema and poor clinical outcome mediated by collateral status. Patients with higher BGL might be targeted by adjuvant anti-edematous treatment.
Decompressive craniectomy in malignant MCA infarction in times of mechanical thrombectomy
BackgroundMechanical thrombectomies (MT) in stroke have changed the standard treatment regimen with a continuous increase of MTs during the last years. A subsequent reduction in the rates of decompressive craniectomies (DC) as well as a change in clinical characteristics of patients undergoing an additional DC after MT may be assumed. Therefore, objective of this study was to investigate the influence of nowadays regularly performed MT on patients undergoing DC.MethodsPatients with DC due to cerebral infarctions between January 2009 and January 2018 were included. Patients’ clinical presentation and surgical parameters were collected retrospectively. Initial GCS and NIHSS, extent of the stroke, time interval from symptom onset to DC, and neurological outcome were compared between patients with and without thrombectomy.ResultsA total of 5469 ischemic strokes were treated in the investigated period, leading to DC in 119 cases (2.2%). A decrease in the rate of performed DCs was recorded: in 2009, 2.8% of ischemic stroke patients underwent surgery compared to 1.9% in 2017. In the meantime, the number of MTs in our center has increased from 84 in 2014 to 160 in 2017. MT was performed in 32 patients prior to DC. No significant differences could be seen between the groups regarding age, initial NIHSS (median 18 in both groups, p = 0.81), extent of the infarctions prior to DC (median ASPECTS 0 in both groups, p = 0.87), time interval from symptom onset to DC, and neurological outcome.ConclusionsThe introduction of routinely performed MT as part of the standard treatment regimen for ischemic stroke has led to a decrease in DCs. However, DC patients with and without MT showed no differences regarding their initial clinical criteria and outcome. These results suggest that earlier DC studies in patients with MCA infarction also apply for the collective of thrombectomized patients.
Stroke patients treated by thrombectomy in real life differ from cohorts of the clinical trials: a prospective observational study
Background Randomized controlled trials (RCTs) demonstrated efficacy and safety of endovascular treatment (ET) in anterior circulation large vessel occlusions (LVO). We aimed at investigating how stroke patients treated by thrombectomy in clinical practice and their outcome compare to cohorts and results of thrombectomy trials. Methods In a prospective study, we consecutively included stroke patients treated by thrombectomy (2015–2017). Baseline characteristics, procedural and outcome data were analyzed. Outcome was assessed by modified Rankin Scale (mRS) at 90 days. Ordinal regression analysis was performed to identify predictors of outcome. Results Thrombectomy was applied in 264 patients (median 75 years, 49.6% female). Median baseline National Institutes of Health Stroke Scale (NIHSS) was 16, 58.0% received concomitant intravenous thrombolysis, 62.1% were referred from external hospitals. Median Alberta Stroke Program Early CT Score (ASPECTS) was 7. Successful recanalization (modified Thrombolysis in Cerebral Infarction Score, mTICI 2b/3) was achieved in 72.0%. Symptomatic intracranial hemorrhage (sICH) occurred in 4.5%. Independent outcome (mRS 0–2) was achieved in 26.2%, poor outcome (mRS 5–6) in 49.2%. Only 33.5% met the stringent enrolment criteria of previous RCTs. Lower age, baseline NIHSS, pre-stroke mRS, higher ASPECTS, and successful recanalization were independent predictors of favourable outcome. Conclusions The majority of stroke patients treated by ET in clinical practice would not have qualified for randomization in prior RCTs. Outcome in real-life patient cohorts is worse than in the highly selected cohorts from randomized trials, while rates of successful recanalization, sICH and outcome predictors are the same. Our findings support ET in broader patient populations than in the RCTs and may improve treatment decision in individual stroke patients with LVO in clinical practice.
Reasons for failed endovascular recanalization attempts in stroke patients
PurposeMechanical thrombectomy (MT) is a highly effective therapy in patients with acute ischemic stroke due to large vessel occlusion (LVO). However, complete recanalization of the occluded vessel cannot be achieved in all patients, leading to poor clinical outcome. We analyzed the reasons for failed recanalization to help direct future improvements in therapy.Methods648 consecutive stroke patients with LVO and an MT attempt were retrospectively analyzed for none or minimal recanalization, assessed according to the Thrombolysis in Cerebral Infarction (TICI) score (0/1). Procedural parameters were evaluated in a standardized approach. Among other variables, number of retrieval attempts, devices, duration of the intervention, and rescue methods were analyzed.ResultsTICI 0/1 was observed in 72/648 patients (11%). In these patients, the thrombus could not be reached in 21% (n=15/72), was reached but not passed in 21% (n=15/72), and was reached and passed in 58% (n=42/72). Only a minor degree of initial recanalization was achieved in 19% (n=8/42) of patients with a reached occlusion during the course of the intervention. Furthermore, a higher number of passes with a single retriever device led to significant prolongation of the intervention. Therefore, major reasons for failed endovascular recanalization were difficult anatomical access and hard or resistant occlusions that might reflect hard thrombi or pre-existing atherosclerotic stenosis. Procedural complications such as dissection or perforation played a minor role.ConclusionIn stroke patients with failed MT attempts, approximately 60% of occlusions can be passed. In such cases, rescue therapy might be considered to improve recanalization and clinical outcome. Further development of access devices might help in the remaining cases where the microcatheter could not be manipulated to or through the occlusion.
Early clinical surrogates for outcome prediction after stroke thrombectomy in daily clinical practice
Background and purposeTo investigate early clinical surrogates for long-term independency of patients treated with thrombectomy for large vessel occlusion stroke in daily clinical routine.MethodsAll patients with anterior circulation stroke enrolled in the German Stroke Registry-Endovascular Treatment from 07/2015 to 04/2018 were analysed. National Institute of Health Stroke Scale (NIHSS) on admission, NIHSS percentage change, NIHSS delta and NIHSS at 24 hours as well as existing binary definitions of early neurological improvement (ENI; improvement of 8 (major ENI)/10 (dramatic ENI) NIHSS points or reaching 0/1 were compared for predicting functional outcome at 90 days using the modified Rankin Scale (mRS). Excellent and favourable outcome were defined as 0–1 and 0–2, respectively.ResultsAmong 2262 endovasculary treated patients with acute ischaemic anterior circulation stroke, NIHSS at 24 hours had the highest discriminative ability to predict excellent (receiver operator characteristics (ROC)NIHSS 24 hours area under the curve (AUC) 0.86 (0.84–0.88)) and favourable long-term functional outcome (ROCNIHSS 24 hours AUC 0.86 (0.85–0.88)) in comparison to NIHSS percentage change (ROC% change AUC mRS ≤1: 0.81 (0.78–0.83) mRS ≤2: 0.81 (0.79–0.83)), NIHSS delta change (ROCΔ change AUC mRS ≤1: 0.74 (0.72–0.77), mRS ≤2: 0.77 (0.74–0.79)) and NIHSS admission (ROCAdm AUC mRS ≤1: 0.70 (0.68–0.73), mRS ≤2: 0.67 (0.68–0.71)). Advanced age was the only independent predictor (adjusted OR 1.05, 95% CI 1.03 to 1.07, p<0.001) for turning the outcome prognosis from favourable (mRS ≤2) to poor (mRS ≥4) at 90 days.ConclusionThe NIHSS at 24 hours postintervention with a threshold of ≤8 points serves best as a surrogate for long-term functional outcome after thrombectomy for anterior circulation stroke in daily clinical practice. Only advanced age significantly decreases its predictive value.
ASPECTS Interobserver Agreement of 100 Investigators from the TENSION Study
Purpose Evaluating the extent of cerebral ischemic infarction is essential for treatment decisions and assessment of possible complications in patients with acute ischemic stroke. Patients are often triaged according to image-based early signs of infarction, defined by Alberta Stroke Program Early CT Score (ASPECTS). Our aim was to evaluate interrater reliability in a large group of readers. Methods We retrospectively analyzed 100 investigators who independently evaluated 20 non-contrast computed tomography (NCCT) scans as part of their qualification program for the TENSION study. Test cases were chosen by four neuroradiologists who had previously scored NCCT scans with ASPECTS between 0 and 8 and high interrater agreement. Percent and interrater agreements were calculated for total ASPECTS, as well as for each ASPECTS region. Results Percent agreements for ASPECTS ratings was 28%, with interrater agreement of 0.13 (95% confidence interval, CI 0.09–0.16), at zero tolerance allowance and 66%, with interrater agreement of 0.32 (95% CI: 0.21–0.44), at tolerance allowance set by TENSION inclusion criteria. ASPECTS region with highest level of agreement was the insular cortex (percent agreement = 96%, interrater agreement = 0.96 (95% CI: 0.94–0.97)) and with lowest level of agreement the M3 region (percent agreement = 68%, interrater agreement = 0.39 [95% CI: 0.17–0.61]). Conclusion Interrater agreement reliability for total ASPECTS and study enrollment was relatively low but seems sufficient for practical application. Individual region analysis suggests that some are particularly difficult to evaluate, with varying levels of reliability. Potential impairment of the supraganglionic region must be examined carefully, particularly with respect to the decision whether or not to perform mechanical thrombectomy.
Predicting the tissue outcome of acute ischemic stroke from acute 4D computed tomography perfusion imaging using temporal features and deep learning
Predicting follow-up lesions from baseline CT perfusion (CTP) datasets in acute ischemic stroke patients is important for clinical decision making. Deep convolutional networks (DCNs) are assumed to be the current state-of-the-art for this task. However, many DCN classifiers have not been validated against the methods currently used in research (random decision forests, RDF) and clinical routine (Tmax thresholding). Specialized DCNs have even been designed to extract complex temporal features directly from spatiotemporal CTP data instead of using standard perfusion parameter maps. However, the benefits of applying deep learning to source or deconvolved CTP data compared to perfusion parameter maps have not been formally investigated so far. In this work, a modular UNet-based DCN is proposed that separates temporal feature extraction from tissue outcome prediction, allowing for both model validation using perfusion parameter maps as well as end-to-end learning from spatiotemporal CTP data. 145 retrospective datasets comprising baseline CTP imaging, perfusion parameter maps, and follow-up non-contrast CT with manual lesion segmentations were assembled from acute ischemic stroke patients treated with intravenous thrombolysis alone (IV; n=43) or intra-arterial mechanical thrombectomy (IA; n=102) with or without combined IV. Using the perfusion parameter maps as input, the proposed DCN (mean Dice: 0.287) outperformed the RDF (0.262) and simple Tmax-thresholding (0.249). The performance of the proposed DCN was approximately equal using features optimized from the deconvolved residual curves (0.286) compared to perfusion parameter maps (0.287), while using features optimized from the source concentration-time curves (0.296) provided the best tissue outcome predictions.