Publications by authors named "Michael Knauth"

83 Publications

Derivo embolization device in the treatment of unruptured intracranial aneurysms: a prospective multicenter study.

J Neurointerv Surg 2020 Sep 8. Epub 2020 Sep 8.

Department of Intracranial Endovascular Therapy, Alfried Krupp Krankenhaus Essen, Essen, Germany.

Background: Flow diverters (FD) are used regularly for the endovascular treatment of unruptured intracranial aneurysms. We aimed to assess the safety and effectiveness of the Derivo embolization device (DED) with respect to long-term clinical and angiographic outcomes.

Methods: A prospective multicenter trial was conducted at 12 centers. Patients presenting with modified Rankin Score (mRS) of 0-1, treated for unruptured intracranial aneurysms with DED were eligible. Primary endpoint was the mRS assessed at 18 months with major morbidity defined as mRS 3-5. Satisfactory angiographic occlusion was defined as 3+4 on the Kamran scale.

Results: Between July 2014 and February 2018, 119 patients were enrolled. Twenty-three patients were excluded. Ninety-six patients, 71 (74%) female, mean age 54±12.0 years, were included in the analysis. Mean aneurysm size was 14.2±16.9 mm. The mean number of devices implanted per patient was 1.2 (range 1-3). Clinical follow-up at 18 months was available in 90 (94%) patients, resulting in a mean follow-up period of 14.8±5.2 months. At last available follow-up of 96 enrolled patients, 91 (95%) remained mRS 0-1. The major morbidity rate (mRS 3-5) was 3.1% (3/96), major stroke rate was 4.2% (4/96), and mortality was 0%. Follow-up angiographies were available in 89 (93%) patients at a median of 12.4±5.84 months with a core laboratory adjudicated satisfactory aneurysm occlusion in 89% (79/89).

Conclusion: Our results suggest that DED is a safe and effective treatment for unruptured aneurysms with high rates of satisfactory occlusion and comparably low rates of permanent neurological morbidity and mortality.

Trial Registration: DRKS00006103.
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http://dx.doi.org/10.1136/neurintsurg-2020-016303DOI Listing
September 2020

Angioplasty with the scepter C dual lumen balloon catheter and postprocedural result evaluation in patients with subarachnoid hemorrhage related vasospasms.

BMC Neurol 2020 Jun 29;20(1):260. Epub 2020 Jun 29.

Department of Neuroradiology, University Medical Center Goettingen, Robert-Koch-Str. 40, 37075, Gottingen, Germany.

Background: Delayed cerebral ischemia is one of the leading causes of death and disability in patients with subarachnoid hemorrhage (SAH). Transluminal balloon angioplasty (TBA) is a therapeutic option for vasospasms affecting proximal intracranial arteries.

Methods: Aim of this study was to report our experience using the Scepter C balloon catheter in the treatment of cerebral vasospasms due to SAH and evaluate the postprocedural result with the iFlow tool. We reviewed cases of patients treated at our hospital from 2014 to 2018. Patients were screened with transcranial doppler sonography (TCD) and multimodal computed tomography. In case of significant vasospasms, patients were transferred to the angiography suite and treated. We used the iFlow tool to quantify and evaluate the angiographic results by measuring and comparing peak density values on angiograms before and after the mechanical dilation.

Results: The use of the Scepter C balloon catheter was feasible in all cases. Vasospasms of the anterior cerebral artery were treated in ten cases. We didn't observe complications or vasospasm recurrences of the treated arteries. The temporal difference between distal vessels and the proximal reference vessel was significantly reduced from a mean of 53%, prior to dilatation, to 26% after the treatment. The difference between pre-dilatation and post-dilatation values was statistically significant for the anterior circulation at the proximal as well as at the distal vessels.

Conclusions: We successfully treated endovascularly patients suffering from cerebral vasospasms refractory to medical treatment using the Scepter C balloon catheter. We didn't observe any complications. The therapeutic effect could be easily and reliably assessed with the iFlow tool.
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http://dx.doi.org/10.1186/s12883-020-01792-3DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7322884PMC
June 2020

One-Stop Management of 230 Consecutive Acute Stroke Patients: Report of Procedural Times and Clinical Outcome.

J Clin Med 2019 Dec 11;8(12). Epub 2019 Dec 11.

Department of Neurology, University Medical Center Goettingen, 37075 Goettingen, Germany.

Background And Purpose: Rapid thrombectomy for acute ischemic stroke caused by large vessel occlusion leads to improved outcome. Optimizing intrahospital management might diminish treatment delays. To examine if one-stop management reduces intrahospital treatment delays and improves functional outcome of acute stroke patients with large vessel occlusion.

Methods: We performed a single center, observational study from June 2016 to November 2018. Imaging was acquired with the latest generation angiography suite at a comprehensive stroke center. Two-hundred-thirty consecutive adults with suspected acute stroke presenting within 6 h after symptom onset with a moderate to severe National Institutes of Health Stroke Scale (≥10 in 2016; ≥7 since January 2017) were directly transported to the angiography suite by bypassing multidetector CT. Noncontrast flat-detector CT and biphasic flat-detector CT angiography were acquired with an angiography system. In case of a large vessel occlusion patients remained in the angiography suite, received intravenous rtPA therapy and underwent thrombectomy. As primary endpoints, door-to-reperfusion times and functional outcome at 90 days were recorded and compared in a case-control analysis with matched prior patients receiving standard management.

Results: A total of 230 patients (123 women, median age of 78 years (Interquartile Range (IQR) 69-84)) were included. Median symptom-to-door time was 130 min (IQR 70-195). Large vessel occlusion was diagnosed in 166/230 (72%) patients; 64/230 (28%) had conditions not suitable for thrombectomy. Median door-to-reperfusion time for M1 occlusions was 64 min (IQR 56-87). Compared to 43 case-matched patients triaged with multidetector CT, median door-to-reperfusion time was reduced from 102 (IQR 85-117) to 68 min (IQR 53-89; < 0.001). Rate of good functional outcome was significantly better in the one-stop management group ( = 0.029). Safety parameters (mortality, sICH, any hemorrhage) did not differ significantly between groups.

Conclusions: One-stop management for stroke triage reduces intrahospital time delays in our specific hospital setting.
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http://dx.doi.org/10.3390/jcm8122185DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6947228PMC
December 2019

Evaluation of an optimized metal artifact reduction algorithm for flat-detector angiography compared to DSA imaging in follow-up after neurovascular procedures.

BMC Med Imaging 2019 08 14;19(1):66. Epub 2019 Aug 14.

Institute for Diagnostic and Interventional Neuroradiology, University Medicine Göttingen, Robert Koch Straße 40, 37075, Göttingen, Germany.

Background: Flat detector CT - angiography (FDCTA) has become a valuable imaging tool in post- and peri-interventional imaging after neurovascular procedures. Metal artifacts produced by radiopaque implants like clips or coils still impair image quality.

Methods: FDCTA was performed in periprocedural or follow-up imaging of 21 patients, who had received neurovascular treatment. Raw data was sent to a dedicated workstation and subsequently a metal artifact reduction algorithm (MARA) was applied. Two neuroradiologists examined the images.

Results: Application of MARA improved image appearance and led to a significant reduction of metal artifacts. After application of MARA only 8 datasets (34% of the images) were rated as having many or extensive artifacts, before MARA 15 (65%) of the images had extensive or many artifacts. Twenty percent more cases of reperfusion were diagnosed after application of MARA, congruent to the results of digital subtraction angiography (DSA) imaging. Also 3 (13% of datasets) images, which could not be evaluated before application of MARA, could be analyzed after metal artifact reduction and reperfusion could be excluded.

Conclusion: Application of MARA improved image evaluation, reduced the extent of metal artifacts, and more cases of reperfusion could be detected or excluded, congruent to DSA imaging.
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http://dx.doi.org/10.1186/s12880-019-0352-2DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6694691PMC
August 2019

Outcome Prediction Using Perfusion Parameters and Collateral Scores of Multi-Phase and Single-Phase CT Angiography in Acute Stroke: Need for One, Two, Three, or Thirty Scans?

J Stroke 2018 Sep 30;20(3):362-372. Epub 2018 Sep 30.

Institute of Neuroradiology, University Medical Center Goettingen, Goettingen, Germany.

Background And Purpose: Collateral status is an important factor determining outcome in acute ischemic stroke (AIS). Hence, different collateral scoring systems have been introduced. We applied different scoring systems on single- and multi-phase computed tomography (CT) angiography (spCTA and mpCTA) and compared them to CT perfusion (CTP) parameters to identify the best method for collateral evaluation in patients with AIS.

Methods: A total of 102 patients with AIS due to large vessel occlusion in the anterior circulation who underwent multimodal CT imaging and who were treated endovascularly were included. Collateral status was assessed on spCTA and mpCTA using four different scoring systems and compared to CTP parameters. Logistic regression was performed for predicting favorable outcome.

Results: All collateral scores correlated well with each other and with CTP parameters. Comparison of collateral scores stratified by extent of perfusion deficit showed relevant differences between groups (P<0.01 for each). An spCTA collateral score discriminated best between favorable and unfavorable outcome as determined using the modified Rankin Scale 3 months after stroke.

Conclusion: s Collateral status evaluated on spCTA may suffice for outcome prediction and decision making in AIS patients, potentially obviating further imaging modalities like mpCTA or CTP.
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http://dx.doi.org/10.5853/jos.2018.00605DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6186923PMC
September 2018

Carotid artery flow as determined by real-time phase-contrast flow MRI and neurovascular ultrasound: A comparative study of healthy subjects.

Eur J Radiol 2018 Sep 18;106:38-45. Epub 2018 Jul 18.

Biomedizinische NMR Forschungs GmbH am Max-Planck-Institut für biophysikalische Chemie, Göttingen, Germany; German Center for Cardiovascular Research (DZHK), Partner Site Göttingen, Germany. Electronic address:

Background: The assessment of carotid artery flow by neurovascular ultrasound (nvUS) can be complemented by real-time phase-contrast (RT-PC) flow MRI which apart from quantitative flow parameters offers velocity distributions across the entire vessel lumen.

Materials And Methods: The feasibility and diagnostic potential of RT-PC flow MRI was evaluated in 20 healthy volunteers in comparison to conventional nvUS. RT-PC flow MRI at 40 ms temporal resolution and 0.8 mm in-plane resolution resulted in velocity maps with low phase noise and high spatiotemporal accuracy by exploiting respective advances of a recent nonlinear inverse model-based reconstruction. Peak-systolic velocities (PSV), end-diastolic velocities (EDV), flow volumes and comprehensive velocity profiles were determined in the common, internal and external carotid artery on both sides.

Results: Flow characteristics such as pulsatility and individual abnormalities shown on nvUS could be reproduced and visualized in detail by RT-PC flow MRI. PSV to EDV differences revealed good agreement between both techniques, mean PSV and EDV were significantly lower and flow volumes were higher for MRI.

Conclusion: Our findings suggest that RT-PC flow MRI adds to clinical diagnostics, e.g. by alterations of dynamic velocity distributions in patients with carotid stenosis. Lower PSV and EDV values than for nvUS mainly reflect the longer MRI acquisition time which attenuates short peak velocities, while higher flow volumes benefit from a proper assessment of the true vessel lumen.
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http://dx.doi.org/10.1016/j.ejrad.2018.07.011DOI Listing
September 2018

Optimized Management of Endovascular Treatment for Acute Ischemic Stroke.

J Vis Exp 2018 01 18(131). Epub 2018 Jan 18.

Institute of Neuroradiology, University Medical Center Goettingen;

This manuscript describes a streamlined protocol for the management of patients with acute ischemic stroke, which aims at the minimization of time from hospital admission to reperfusion. Rapid restoration of cerebral blood flow is essential for the outcomes of patients with acute ischemic stroke. Endovascular treatment (EVT) has become the standard of care to accomplish this in patients with acute stroke due to large vessel occlusion (LVO). To achieve reperfusion of ischemic brain regions as fast as possible, all in-hospital time delays have to be carefully avoided. Therefore, management of patients with acute ischemic stroke was optimized with an interdisciplinary standard operating procedure (SOP). Stroke neurologists, diagnostic as well as interventional neuroradiologists, and anesthesiologists streamlined all necessary processes from patient admission and diagnosis to EVT of eligible patients. Target times for every step were established. Actually achieved times were prospectively recorded along with clinical data and imaging scores for all endovascularly treated stroke patients. These data were regularly analyzed and discussed in interdisciplinary team meetings. Potential issues were evaluated and all staff involved was trained to adhere to the SOP. This streamlined patient management approach and enhanced interdisciplinary collaboration reduced time from patient admission to reperfusion significantly and was accompanied by a beneficial effect on clinical outcomes.
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http://dx.doi.org/10.3791/56397DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5908663PMC
January 2018

High Systolic Blood Pressure after Successful Endovascular Treatment Affects Early Functional Outcome in Acute Ischemic Stroke.

Cerebrovasc Dis 2018 24;45(1-2):18-25. Epub 2017 Nov 24.

Department of Neurology, University Medical Center Göttingen, Göttingen, Germany.

Background: Endovascular treatment (EVT) has been shown to significantly improve functional outcome in patients with acute large cerebral vessel occlusions. To date, no evidence-based recommendations on blood pressure management after successful EVT exist. Previous studies showed an association between high pre-EVT systolic blood pressure (SBP) and functional outcome, but do not answer the question on how to manage blood pressure after successful recanalization. The purpose of this study was to determine the role of blood pressure measurements as a predictor for early functional outcome in patients with successful EVT.

Methods: Prospectively derived data from patients with acute large vessel occlusion within the anterior circulation and EVT was analyzed in this monocentric study. Mean systolic- and maximum SBP as well as SBP-peaks have been obtained for the first 24 h after successful EVT. Predictive value of SBP for discharge modified Rankin Scale (mRS) ≤2 has been investigated using logistic regression models.

Results: From 168 patients with successful EVT, 74 (44%) had a favorable outcome with an mRS ≤2. Mean- (127 vs. 131 mm Hg, p = 0.035) and maximum SBP (157 vs. 169 mm Hg, p < 0.001) as well as the number of SBP-peaks (0 vs. 1.5, p = 0.004) were lower in patients with favorable outcomes. Multivariable logistic regression showed high mean- and maximum SBP to predict unfavorable outcomes. Cutoff mean SBP was 141 mm Hg and maximum SBP 159 mm Hg.

Conclusions: High SBP in the first 24 h after recanalization of acute anterior cerebral vessel occlusions is associated with unfavorable functional outcome. Interventional studies are needed to determine the role of SBP management as a modifiable parameter in the early phase after successful EVT.
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http://dx.doi.org/10.1159/000484720DOI Listing
March 2019

One-Stop Management of Acute Stroke Patients: Minimizing Door-to-Reperfusion Times.

Stroke 2017 11 10;48(11):3152-3155. Epub 2017 Oct 10.

From the Department of Neuroradiology (M.N.P., D.B., K.S., I.T., J.R.L., J.T., M.K.), Neurology (I.L.M., M.B., J.L.), and Medical Statistics (A.Z.), University Medical Center Göttingen, Germany; and Department of Radiology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA (K.S.).

Background And Purpose: Intrahospital time delays significantly affect the neurological outcome of stroke patients with large-vessel occlusion. This study was conducted to determine whether a one-stop management can reduce intrahospital times of patients with acute large-vessel occlusion.

Methods: In this observational study, we report the first 30 consecutive stroke patients imaged and treated in the same room. As part of our protocol, we transported patients with a National Institutes of Health Stroke Scale score of ≥10 directly to the angio suite, bypassing multidetector computed tomography (CT). Preinterventional imaging consisted of noncontrast flat detector CT and flat detector CT angiography, acquired with an angiography system. Patients with large-vessel occlusions remained on the angio table and were treated with mechanical thrombectomy; patients with small artery occlusions were treated with intravenous thrombolysis, whereas patients with an intracranial hemorrhage and stroke mimics were treated as per guidelines. Door-to-groin puncture times were recorded and compared with our past results.

Results: Thirty patients were transferred directly to our angio suite from June to December 2016. The time from symptom onset to admission was 105 minutes. Ischemic stroke was diagnosed in 22 of 30 (73%) patients, 4 of 30 (13.5%) had an intracranial hemorrhage, and 4 of 30 (13.5) were diagnosed with a Todd's paresis. Time from admission to groin puncture was 20.5 minutes. Compared with 44 patients imaged with multidetector CT in the first 6 months of 2016, door-to-groin times were significantly reduced (54.5 minutes [95% confidence interval, 47-61] versus 20.5 minutes [95% confidence interval, 17-26]).

Conclusions: In this small series, a one-stop management protocol of selected stroke patients using latest generation flat detector CT led to a significant reduction of intrahospital times.
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http://dx.doi.org/10.1161/STROKEAHA.117.018077DOI Listing
November 2017

Comparing different thrombectomy techniques in five large-volume centers: a 'real world' observational study.

J Neurointerv Surg 2018 06 28;10(6):525-529. Epub 2017 Sep 28.

Institute for Diagnostic and Interventional Neuroradiology, University Medical Center Goettingen, Goettingen, Germany.

Background And Purpose: Thrombectomy has become the standard of care for acute ischaemic stroke due to large vessel occlusion. Aim of this study was to compare the radiological outcomes and time metrics of the various thrombectomy techniques.

Methods: In this retrospective, multicenter study we analysed the data of 450 patients with occlusion of the anterior circulation, treated in five high-volume center from 2013 to 2016. The treatment techniques were divided in three categories: first-pass use of a large-bore aspiration-catheter; first-pass use of a stent-retriever; and primary combined approach (PCA) of an aspiration-catheter and stent-retriever. Primary endpoints were successful reperfusion and groin to reperfusion time. Secondary endpoints were the number of attempts and occurrence of emboli in new territory (ENT). The primary analysis was based on the intention to treat groups (ITT).

Results: The ITT-analysis showed significantly higher reperfusion rates, with 86% of successful reperfusion in the PCA-group compared with 73% in the aspiration group and 65% in the stent-retriever group. There was no significant difference in groin to reperfusion time regarding the used technique. The secondary analysis showed an impact of the technique on the number of attempts and the occurrence of ENTs. Lowest ENT rates and attempts were reported with the combined approach.

Conclusions: The combined first-pass deployment of a stent-retriever and an aspiration-catheter was the most effective technique for reperfusion of anterior circulation large vessel occlusion. Our results correlate with the latest single-centrere studies, reporting very high reperfusion rates with PCA variations.
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http://dx.doi.org/10.1136/neurintsurg-2017-013394DOI Listing
June 2018

Association between Embolic Stroke Patterns, ESUS Etiology, and New Diagnosis of Atrial Fibrillation: A Secondary Data Analysis of the Find-AF Trial.

Stroke Res Treat 2017 27;2017:1391843. Epub 2017 Apr 27.

Department of Neurology, University Medicine Göttingen, Göttingen, Germany.

. Atrial fibrillation (AF) is an important cause of embolic stroke of undetermined source (ESUS). Imaging-patterns like multiple infarcts, simultaneous involvement of different circulations, infarcts of different ages, and isolated cortical infarcts are likely to indicate cardioembolic stroke. The aim of our study was to evaluate the association between embolic stroke patterns, ESUS, and the new diagnosis of AF. . Stroke etiology and imaging characteristics from patients included in the Find-AF study were obtained. Embolic stroke patterns in CT- or MR-imaging were correlated with the diagnosis of ESUS as well as the short- (on baseline ECG and during 7-day Holter) and long-term (12-month follow-up) diagnosis of AF. . From 281 patients included in the Find-AF study, 127 (45.2%) patients with ischemic lesions detected in CT or MRI were included. 26 (20.5%) of these patients had ESUS. At least one embolic stroke pattern was detected in 67 (52.7%) patients. Embolic stroke patterns were not associated with ESUS (OR 1.57, 0.65-3.79, = 0.317), the short-term (OR 0.64, 0.26-1.58, = 0.327) or long-term diagnosis of AF (OR 0.72, 0.31-1.68, = 0.448). . This secondary data analysis of the Find-AF study could not provide evidence for an association between embolic stroke patterns, ESUS, and the new diagnosis of AF.
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http://dx.doi.org/10.1155/2017/1391843DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5425845PMC
April 2017

Transcranial doppler sonography is not a valid diagnostic tool for detection of basilar artery stenosis or in-stent restenosis: a retrospective diagnostic study.

BMC Neurol 2017 May 11;17(1):89. Epub 2017 May 11.

Department of Neurology, University of Goettingen, Robert-Koch-Str. 40, 37075, Goettingen, Germany.

Background: There are contradictory reports concerning the validity of transcranial sonography (TCD and TCCS) for examinations of the basilar artery. Here we investigated sensitivity and specificity of transcranial sonography for the detection of basilar artery stenosis and in-stent-restenosis compared to cerebral angiography.

Methods: We analyzed data of 104 examinations of the basilar artery. The association between sonographic peak systolic velocity (PSV) and degree of stenosis obtained by cerebral angiography was evaluated applying Spearman's correlation coefficient. Receiver Operating Characteristics (ROC) curves and areas under the curve (AUC) were calculated for the detection of a ≥50% stenosis defined by angiography. Optimal cut-off was derived using the Youden-index.

Results: A weak but statistically significant correlation between PSV and the degree of stenosis was found (n=104, rho=0.35, p<0.001). ROC analysis for a detection of ≥50% stenosis showed an AUC of 0.70, a sensitivity of 74.0% and a specificity of 65.0% at the optimal cut off of 124 cm/s. Results were consistent when analyzing examinations done in stented and unstented arteries separately (TCD VS DSA/CTA in unstented artery: AUC=0.66, sensitivity 61.0%, specificity 65.0%, TCD/TCCS VS DSA in stented artery: AUC=0.63, sensitivity 71.0%, specificity 82.0%). Comparing TCCS measurements exclusively to angiography, ROC analysis showed an AUC of 1.00 for the detection of an in-stent-restenosis ≥50% with a sensitivity and specificity of 100% when a PSV of 132 cm/s was used as a cut off value.

Conclusion: Validity of TCD in the assessment of basilar artery stenosis or in-stent restenosis is poor. First results for TCCS are promising, but due to the small samplesize further studies with larger samples sizes are warranted.
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http://dx.doi.org/10.1186/s12883-017-0872-8DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5426050PMC
May 2017

Retriever first embolectomy (ReFirE): An alternative approach for challenging cervical access.

Interv Neuroradiol 2017 Aug 27;23(4):412-415. Epub 2017 Apr 27.

Department of Diagnostic and Interventional Neuroradiology, University Medical Centre Göttingen, Georg-August University, Göttingen, Germany.

After endovascular treatment became the standard of care procedure for acute ischaemic stroke with large artery occlusion in 2015 the number of performed interventions has increased dramatically. Especially because age is no exclusion criterion for endovascular treatment, a relevant number of patients with difficult to access carotid arteries has to be treated. In these patients a direct puncture of the carotid is a valuable tool but is associated with severe complications and an initial learning curve. We therefore developed the so called retriever first embolectomy (ReFirE) technique in which a stentretriever is deployed over a 5F diagnostic catheter and a microcatheter to establish a stable anchor prior to accessing the internal carotid artery/intracranial vasculature with an 8F guide catheter and a 5F/6F intermediate catheter. We hereby report the first case in which we performed a thrombectomy applying our novel technique.
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http://dx.doi.org/10.1177/1591019917701114DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5684898PMC
August 2017

Computed tomography perfusion-based selection of endovascularly treated acute ischaemic stroke patients - Are there lessons to be learned from the pre-evidence era?

Neuroradiol J 2017 Apr 1;30(2):138-143. Epub 2017 Jan 1.

1 Department of Neuroradiology, Georg-August University Goettingen, Germany.

Introduction Some of the latest groundbreaking trials suggest that noncontrast cranial computed tomography and computed tomography-angiography are sufficient tools for patient selection within six hours of symptom onset. Before endovascular stroke therapy became the standard of care, patient selection was one of the most useful tools to avoid futile reperfusions. We report the outcomes of endovascularly treated stroke patients selected with a perfusion-based paradigm and discuss the implications in the current era of endovascular treatment. Material and methods After an interdisciplinary meeting in September 2012 we agreed to select thrombectomy candidates primarily based on computed tomography perfusion with a cerebral blood volume Alberta Stroke Program Early Computed Tomography Scale (CBV-ASPECTS) of <7 being a strong indicator of futile reperfusion. In this study, we retrospectively screened all patients with an M1 thrombosis in our neurointerventional database between September 2012 and December 2014. Results In 39 patients with a mean age of 69 years and a median admission National Institute of Health Stroke Scale of 17 the successful reperfusion rate was 74% and the favourable outcome rate at 90 days was 56%. Compared to previously published data from our database 2007-2011, we found that a two-point increase in median CBV-ASPECTS was associated with a significant increase in favourable outcomes. Conclusion Computed tomography perfusion imaging as an additional selection criterion significantly increased the rate of favourable clinical outcome in patients treated with mechanical thrombectomy. Although computed tomography perfusion has lost impact within the six-hour period, we still use it in cases beyond six hours as a means to broaden the therapeutic window.
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http://dx.doi.org/10.1177/1971400916689372DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5433588PMC
April 2017

Early computed tomography-based scores to predict decompressive hemicraniectomy after endovascular therapy in acute ischemic stroke.

PLoS One 2017 10;12(3):e0173737. Epub 2017 Mar 10.

Department of Neuroradiology, University Medical Center Goettingen, Goettingen, Germany.

Background: Identification of patients requiring decompressive hemicraniectomy (DH) after endovascular therapy (EVT) is crucial as clinical signs are not reliable and early DH has been shown to improve clinical outcome. The aim of our study was to identify imaging-based scores to predict the risk for space occupying ischemic stroke and DH.

Methods: Prospectively derived data from patients with acute large artery occlusion within the anterior circulation and EVT was analyzed in this monocentric study. Predictive value of non-contrast cranial computed tomography (ncCT) and cerebral blood volume (CBV) Alberta Stroke Program Early CT score (ASPECTS) were investigated for DH using logistic regression models and Receiver Operating Characteristic Curve analysis.

Results: From 218 patients with EVT, DH was performed in 20 patients (9.2%). Baseline- (7 vs. 9; p = 0.009) and follow-up ncCT ASPECTS (1 vs. 7, p<0.001) as well as baseline CBV ASPECTS (5 vs. 7, p<0.001) were significantly lower in patients with DH. ncCT (baseline: OR 0.71, p = 0.018; follow-up: OR 0.32, p = <0.001) and CBV ASPECTS (OR 0.63, p = 0.008) predicted DH. Cut-off ncCT-ASPECTS on baseline was 7-, ncCT-ASPECTS on follow-up was 4- and CBV ASPECTS on baseline was 5 points.

Conclusions: ASPECTS could be useful to early identify patients requiring DH after EVT for acute large vessel occlusion.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0173737PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5345861PMC
August 2017

One Stop Management in Acute Stroke: First Mothership Patient Transported Directly to the Angiography Suite.

Clin Neuroradiol 2017 Sep 7;27(3):389-391. Epub 2017 Mar 7.

Department of Neuroradiology, University Medical Center Göttingen, Robert-Koch-Str. 40, 37075, Göttingen, Germany.

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http://dx.doi.org/10.1007/s00062-017-0574-zDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5577051PMC
September 2017

Maximizing First-Pass Complete Reperfusion with SAVE.

Clin Neuroradiol 2018 Sep 13;28(3):327-338. Epub 2017 Feb 13.

Department of Diagnostic and Interventional Radiology, University of Göttingen, Göttingen, Germany.

Background: Endovascular techniques for treatment of large vessel occlusions (LVO) in patients with acute ischemic stroke (AIS) have advanced in recent years. We report a multicenter experience using a combined aspiration and stent retriever technique for mechanical thrombectomy (MT).

Methods: We retrospectively analyzed 32 consecutive MT patients using a novel, combined approach of Stent retriever Assisted Vacuum-locked Extraction (SAVE) by 3 operators at 3 stroke centers. Primary endpoint was successful first-pass reperfusion with a modified Thrombolysis in Cerebral Infarction (mTICI) score of 3. Secondary endpoints were number of passes, time from groin puncture to reperfusion, embolization to new territories (ENT), postinterventional symptomatic intracranial hemorrhage (sICH) and clinical outcome at discharge.

Results: First-pass mTICI 3 reperfusion was achieved in 23 out of 32 patients (72%) with a mean groin puncture to reperfusion time of 36.0 min ± 15.8 and mTICI 3 was accomplished in 25 out of 32 cases (78%) with a maximum of 3 attempts. Successful reperfusion (mTICI ≥ 2b) was achieved in all patients (100%) with a mean time from groin puncture to reperfusion of 44.5 min ± 25.8 and an average of 1.2 ± 0.7 attempts. The rate of ENT was 0% and 1 patient with sICH after MT died on postoperative day 4. At discharge, the median National Institutes of Health Stroke Scale (NIHSS) score was 4 (range 0-17) and favorable neurological outcome by the modified Rankin score (mRS ≤ 2) was achieved in 19 out of 32 patients (59%).

Conclusion: SAVE is fast and appears to be very effective in terms of first-pass complete reperfusion in patients with LVO.
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http://dx.doi.org/10.1007/s00062-017-0566-zDOI Listing
September 2018

Retriever wire supported carotid artery revascularization (ReWiSed CARe) in acute ischemic stroke with underlying tandem occlusion caused by an internal carotid artery dissection: Technical note.

Interv Neuroradiol 2017 Jun 5;23(3):289-292. Epub 2017 Feb 5.

Department of Diagnostic and Interventional Neuroradiology, University Medical Center Göttingen, Germany.

We hereby report a novel technical approach for the treatment of acute stroke with underlying tandem occlusion. The so-called retriever wire supported carotid artery revascularization (ReWiSed CARe) technique, utilizing the wire of a stent-retriever as a guiding wire for carotid artery stenting, is technically feasible in tandem occlusions caused by an internal carotid artery (ICA) dissection or high grade ICA stenosis. This technique eliminates the need to use a long microwire in order to maintain the position inside the true lumen of a dissection. Additionally, it leads to anterograde perfusion through the released stent-retriever during the time of ICA stenting, which is favorable in all tandem occlusion cases.
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http://dx.doi.org/10.1177/1591019917690916DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5490855PMC
June 2017

Effects of Workflow Optimization in Endovascularly Treated Stroke Patients - A Pre-Post Effectiveness Study.

PLoS One 2016 30;11(12):e0169192. Epub 2016 Dec 30.

Department of Neuroradiology, University Medicine Goettingen, Goettingen, Germany.

Endovascular treatment of acute ischemic stroke has become standard of care for patients with large artery occlusion. Early restoration of blood flow is crucial for a good clinical outcome. We introduced an interdisciplinary standard operating procedure (SOP) between neuroradiologists, neurologists and anesthesiologists in order to streamline patient management. This study analyzes the effect of optimized workflow on periprocedural timings and its potential influence on clinical outcome. Data were extracted from a prospectively maintained university hospital stroke database. The standard operating procedure was established in February 2014. Of the 368 acute stroke patients undergoing endovascular treatment between 2008 and 2015, 278 patients were treated prior to and 90 after process optimization. Outcome measures were periprocedural time intervals and residual functional impairment. After implementation of the SOP, time from symptom onset to reperfusion was significantly reduced (median 264 min prior and 211 min after SOP-introduction (IQR 228-32 min and 161-278 min, respectively); P<0.001). Especially faster supply of imaging and prompt transfer of patients to the angiography suite contributed to this effect. Time between hospital admission and groin puncture was reduced by half after process optimization (median 64 min after versus 121 min prior to SOP-introduction (IQR 54-77 min and 96-161 min, respectively); P<0.001). Clinical outcome was significantly better after workflow optimization as measured with the modified Rankin Scale (common odds ratio (OR) 0.56; 95% CI 0.32-0.98; P = 0.038). Optimization of workflow and interdisciplinary teamwork significantly improved the outcome of patients with acute ischemic stroke due to a significant reduction of in-hospital examination, transportation, imaging and treatment times.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0169192PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5201273PMC
July 2017

Bridging-therapy with intravenous recombinant tissue plasminogen activator improves functional outcome in patients with endovascular treatment in acute stroke.

J Neurol Sci 2017 Jan 5;372:300-304. Epub 2016 Dec 5.

Department of Neurology, University Medicine Göttingen, Germany.

Background: Although endovascular treatment for proximal cerebral vessel occlusion is very effective, it remains controversial if intravenous thrombolysis (IVT) prior to endovascular treatment is superior compared to endovascular treatment alone. In this study we compared functional outcomes and recanalization rates of endovascularly treated stroke patients with and without bridging IVT.

Methods: Patients with acute large artery occlusion within the anterior and posterior cerebral circulation eligible for intraarterial revascularization with and without prior IVT were included in this monocentric, prospective observational study. Modified Rankin Scale (mRS) and National Institute of Health Stroke Scale (NIHSS) were determined at baseline, discharge and 90-days follow up after stroke. Successful reperfusion was defined as a Thrombolysis in Cerebral Infarction (TICI) scale 2b-3.

Results: Of the 109 patients included, 81 (74%) received bridging therapy with i.v.-rtPA prior to endovascular treatment, 28 (26%) received endovascular treatment alone. There was no difference in groin-to-reperfusion time between the groups (54 vs 50min; p=0.657), but a trend towards a higher reperfusion rate in patients with bridging therapy (69 vs 15 patients, p=0.099). Mean improvement of the NIHSS during hospitalization was 8 points (SD; ±8) in the bridging-group and 2 points (SD, ±7) in the non-bridging-group (p=0.001). Number of patients with discharge mRS 0-2 (34 vs 5; p=0.024) and 90-days mRS 0-2 (35 vs 6; p=0.061) was higher in the bridging-group compared to the non-bridging-group.

Conclusions: This study provides evidence that bridging therapy with i.v.-rtPA improves functional outcome in patients eligible for endovascular treatment. Further studies are needed to confirm our findings and to identify patients most likely benefitting from bridging therapy.
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http://dx.doi.org/10.1016/j.jns.2016.12.001DOI Listing
January 2017

Computed tomography-based quantification of lesion water uptake identifies patients within 4.5 hours of stroke onset: A multicenter observational study.

Ann Neurol 2016 12;80(6):924-934

Department of Diagnostic and Interventional Neuroradiology, University Medical Center Hamburg-Eppendorf, Hamburg.

Objective: Many patients with stroke cannot receive intravenous thrombolysis because the time of symptom onset is unknown. We tested whether computed tomography (CT)-based quantification of water uptake in the ischemic tissue can identify patients with stroke onset within 4.5 hours, the time window of thrombolysis.

Methods: Perfusion CT was used to identify ischemic brain tissue, and its density was measured in native CT and related to the density of the corresponding area of the contralateral hemisphere to quantify lesion water uptake. The optimal cutoff value of water uptake distinguishing stroke onset within and beyond 4.5 hours was calculated in patients with proximal middle cerebral artery occlusion (derivation cohort) with known time of symptom onset. The so-derived cutoff value was validated in a prospective cohort from other stroke centers.

Results: Of 178 patients of the derivation cohort, 147 (82.6%) had CT within 4.5 hours. Percentage water uptake was significantly lower in patients with stroke onset within compared to beyond 4.5 hours. The area under the receiver operating characteristic curve for distinguishing these patient groups according to percentage water uptake was 0.999 (95% confidence interval = 0.996-1.000, p < 0.001) with an optimal cutoff value of 11.5%. Applying this cutoff to the validation cohort of 240 patients, sensitivity was 98.6%, specificity 90.5%, positive predictive value 99.1%, and negative predictive value 86.4%.

Interpretation: Quantification of brain water uptake identifies stroke patients with symptom onset within 4.5 hours with high accuracy and may guide the decision to use thrombolysis in patients with unknown time of stroke onset. Ann Neurol 2016;80:924-934.
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http://dx.doi.org/10.1002/ana.24818DOI Listing
December 2016

Latest generation of flat detector CT as a peri-interventional diagnostic tool: a comparative study with multidetector CT.

J Neurointerv Surg 2017 Dec 20;9(12):1253-1257. Epub 2016 Dec 20.

Department of Neuroradiology, University Medicine Goettingen, Goettingen, Germany.

Background And Purpose: Flat detector CT (FDCT) has been used as a peri-interventional diagnostic tool in numerous studies with mixed results regarding image quality and detection of intracranial lesions. We compared the diagnostic aspects of the latest generation FDCT with standard multidetector CT (MDCT).

Materials And Methods: 102 patients were included in our retrospective study. All patients had undergone interventional procedures. FDCT was acquired peri-interventionally and compared with postinterventional MDCT regarding depiction of ventricular/subarachnoidal spaces, detection of intracranial hemorrhage, and delineation of ischemic lesions using an ordinal scale. Ischemic lesions were quantified with the Alberta Stroke Program Early CT Scale (ASPECTS) on both examinations. Two neuroradiologists with varying grades of experience and a medical student scored the anonymized images separately, blinded to the clinical history.

Results: The two methods were of equal diagnostic value regarding evaluation of the ventricular system and the subarachnoidal spaces. Subarachnoidal, intraventricular, and parenchymal hemorrhages were detected with a sensitivity of 95%, 97%, and 100% and specificity of 97%, 100%, and 99%, respectively, using FDCT. Gray-white differentiation was feasible in the majority of FDCT scans, and ischemic lesions were detected with a sensitivity of 71% on FDCT, compared with MDCT scans. The mean difference in ASPECTS values on FDCT and MDCT was 0.5 points (95% CI 0.12 to 0.88).

Conclusions: The latest generation of FDCT is a reliable and accurate tool for the detection of intracranial hemorrhage. Gray-white differentiation is feasible in the supratentorial region.
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http://dx.doi.org/10.1136/neurintsurg-2016-012866DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5740543PMC
December 2017

Early termination of THRILL, a prospective study of mechanical thrombectomy in patients with acute ischemic stroke ineligible for i.v. thrombolysis.

Clin Neuroradiol 2016 Dec 5;26(4):499-500. Epub 2016 Sep 5.

Klinik und Poliklinik für Neuroradiologische Diagnostik und Intervention, Universitätsklinikum Hamburg-Eppendorf, Martinistr. 52, 20246, Hamburg, Germany.

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http://dx.doi.org/10.1007/s00062-016-0538-8DOI Listing
December 2016

Transluminal angioplasty and stenting versus conservative treatment in patients with symptomatic basilar artery stenosis : Perspective for future clinical trials.

Clin Neuroradiol 2018 Mar 9;28(1):33-38. Epub 2016 Aug 9.

Department of Neurology, University Medicine Göttingen, Robert-Koch-Str. 40, 37075, Göttingen, Germany.

Purpose: Two recent randomized controlled trials (RCT) consistently showed superiority of aggressive medical treatment versus percutaneous transluminal angioplasty and stenting (PTAS) in patients with intracranial artery stenosis. Patients with symptomatic basilar stenosis have a higher long-term risk of recurrent stroke compared to patients with anterior circulation stenosis but no study has specifically focused on the role of PTAS in this subgroup. The aim of our study was to investigate the subgroup of patients with symptomatic basilar artery stenosis to find evidence for the feasibility of a future clinical trial.

Methods: Patients with ischemic stroke caused by a symptomatic basilar stenosis and admitted to five German tertiary care hospitals were included in this multicenter effectiveness study. Primary outcome was a composite endpoint of stroke recurrence, clinically relevant restenosis, progression and death. Shared frailty Cox regression models were used to compare outcome rates between groups.

Results: Of the 139 patients included in the study 79 (57 %) underwent PTAS and 60 (43 %) conservative treatment alone. The median follow-up period was 300 (IQR 18-738) days. Risks of the primary composite outcome (hazard ratio HR 0.49, 95 % confidence interval CI 0.25-0.97, p = 0.039) and of the key secondary outcomes recurrent stroke (HR 0.42, 95 % CI 0.19-0.95, p = 0.037) and clinically relevant restenosis/progression (HR 0.12, 95 % CI 0.03-0.59, p = 0.009) were lower in patients with PTAS compared to conservative treatment. There was no difference in all-cause mortality between groups (HR 0.98, 95 % CI 0.19-5.09, p = 0.979).

Conclusion: In this retrospective study we could not reproduce the findings from large RCTs on intracranial stenting. Our data could be considered as a basis for a prospective study on patient selection for PTAS in the basilar artery.
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http://dx.doi.org/10.1007/s00062-016-0528-xDOI Listing
March 2018

Aspiration Thrombectomy After Intravenous Alteplase Versus Intravenous Alteplase Alone.

Stroke 2016 09 2;47(9):2331-8. Epub 2016 Aug 2.

From the Mount Sinai Health System, New York, NY (J.M.); St. Vincent Mercy Medical Center, Toledo, OH (O.O.Z.); Universitätsklinikum Carl Gustav Carus, Dresden, Germany (R.v.K.); Texas Stroke Institute, Plano (A.J.Y.); WellStar Health System, Marietta, GA (R.G.); Rush University, Chicago, IL (D.L.); Swedish Medical Center, Denver, CO (D.F.); Central DuPage Hospital, Winfield, IL (H.S.); Riverside Methodist Hospital, Columbus, OH (R.B.); Kaiser Los Angeles, CA (Z.A.A.); St. Joseph's Regional Medical Center, Paterson, NJ (A.G., D.A.); St. Joseph's BNI, Phoenix, AZ (C.M.); Sunrise Hospital and Medical Center, Las Vegas, NV (L.B.); Medical College of Wisconsin, Milwaukee (B.-F.F.); University of Miami Health System, FL (D.Y.); Premier Clinical Neuroscience Institute, Dayton, OH (J.T.); Lutheran Medical Center, Brooklyn, NY (J.F.); University of Chicago Medical Center, IL (S.K.L.); Erlanger Health System, Chattanooga, TN (B.B.); Universitätsklinikum Aachen, Germany (M.W.); Universitätsmedizin Göttingen, Germany (M.K.); Forsyth Medical Center, Winston-Salem, NC (D.H.); Sparrow Hospital, Lansing, MI (S.H.); Houston Methodist Hospital, TX (D.C.); Cedars-Sinai Medical Center, Los Angeles, CA (M.J.A.); Alexian Brothers, Elk Grove, IL (T.M.); The Valley Hospital, Ridgewood, NJ (D.A.); JFK Medical Center, Edison, NJ (J.K.); Holy Cross, Fort Lauderdale, FL (L.M.); and University of Cincinnati, OH (P.K.).

Background And Purpose: Thrombectomy, primarily with stent retrievers with or without adjunctive aspiration, provided clinical benefit across multiple prospective randomized trials. Whether this benefit is exclusive to stent retrievers is unclear.

Methods: THERAPY (The Randomized, Concurrent Controlled Trial to Assess the Penumbra System's Safety and Effectiveness in the Treatment of Acute Stroke; NCT01429350) was an international, multicenter, prospective, randomized (1:1), open label, blinded end point evaluation, concurrent controlled clinical trial of aspiration thrombectomy after intravenous alteplase (IAT) administration compared with intravenous-alteplase alone in patients with large vessel ischemic stroke because of a thrombus length of ≥8 mm. The primary efficacy end point was the percent of patients achieving independence at 90 days (modified Rankin Scale score, 0-2; intention-to-treat analysis). The primary safety end point was the rate of severe adverse events (SAEs) by 90 days (as treated analysis). Patients were randomized 1:1 across 36 centers in 2 countries (United States and Germany).

Results: Enrollment was halted after 108 (55 IAT and 53 intravenous) patients (of 692 planned) because of external evidence of the added benefit of endovascular therapy to intravenous-alteplase alone. Functional independence was achieved in 38% IAT and 30% intravenous intention-to-treat groups (P=0.52). Intention-to-treat ordinal modified Rankin Scale odds ratio was 1.76 (95% confidence interval, 0.86-3.59; P=0.12) in favor of IAT. Secondary efficacy analyses all demonstrated a consistent direction of effect toward benefit of IAT. No differences in symptomatic intracranial hemorrhage rates (9.3% IAT versus 9.7% intravenous, P=1.0) or 90-day mortality (IAT: 12% versus intravenous: 23.9%, P=0.18) were observed.

Conclusions: THERAPY did not achieve its primary end point in this underpowered sample. Directions of effect for all prespecified outcomes were both internally and externally consistent toward benefit. It is possible that an alternate method of thrombectomy, primary aspiration, will benefit selected patients harboring large vessel occlusions. Further study on this topic is indicated.

Clinical Trial Registration: URL: http://www.clinicaltrials.gov. Unique identifier: NCT01429350.
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http://dx.doi.org/10.1161/STROKEAHA.116.013372DOI Listing
September 2016

Added value of CT perfusion compared to CT angiography in predicting clinical outcomes of stroke patients treated with mechanical thrombectomy.

Eur Radiol 2016 Nov 23;26(11):4213-4219. Epub 2016 Feb 23.

Department of Neuroradiology, University Medicine Goettingen, Robert Koch 40, 37075, Goettingen, Germany.

Objectives: CTP images analyzed with the Alberta stroke program early CT scale (ASPECTS) have been shown to be optimal predictors of clinical outcome. In this study we compared two biomarkers, the cerebral blood volume (CBV)-ASPECTS and the CTA-ASPECTS as predictors of clinical outcome after thrombectomy.

Methods: Stroke patients with thrombosis of the M1 segment of the middle cerebral artery were included in our study. All patients underwent initial multimodal CT with CTP and CTA on a modern CT scanner. Treatment consisted of full dose intravenous tissue plasminogen activator, when applicable, and mechanical thrombectomy. Three neuroradiologists separately scored CTP and CTA images with the ASPECTS score.

Results: Sixty-five patients were included. Median baseline CBV-ASPECTS and CTA-ASPECTS for patients with favourable clinical outcome at follow-up were 8 [interquartile range (IQR) 8-9 and 7-9 respectively]. Patients with poor clinical outcome showed a median baseline CBV-ASPECTS of 6 (IQR 5-8, P < 0.0001) and a median baseline CTA-ASPECTS of 7 (IQR 7-8, P = 0.18). Using CBV-ASPECTS and CTA-ASPECTS raters predicted futile reperfusions in 96 % and 56 % of the cases, respectively.

Conclusions: CBV-ASPECTS is a significant predictor of clinical outcome in patients with acute ischemic stroke treated with mechanical thrombectomy.

Key Points: • CBV-ASPECTS is a significant predictor of clinical outcome. • Single phase CTA-ASPECTS has low predictive value. • Using CBV-ASPECTS, raters identified futile reperfusions in 96 % of the cases.
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http://dx.doi.org/10.1007/s00330-016-4257-yDOI Listing
November 2016

Endovascular stroke therapy with the Aperio thrombectomy device.

J Neurointerv Surg 2016 Aug 28;8(8):834-9. Epub 2015 Jul 28.

Section of Neuroradiology, Institute for Diagnostic and Interventional Radiology, University Düsseldorf, Düsseldorf, Germany.

Background: The pharmaceutical therapy for acute ischemic stroke has shortcomings in reopening large vessels and dissolving long thrombi, and endovascular treatment has been found to provide added value. The Aperio thrombectomy device showed promising results in an experimental study. The purpose of this study was to evaluate the device clinically.

Methods: 119 patients with acute stroke were treated in nine centers using the Aperio thrombectomy device. Target vessel, diameter, thrombus length, procedure time, recanalization, number of deployments, additional use of anticoagulants, complications, and the use of additional devices were assessed.

Results: The median thrombus length was 15 mm (range 1.5-20 mm) and the average time from device insertion to recanalization was 30 min (range 5-120 min). Blood flow restoration (Thrombolysis In Cerebral Infarction (TICI) 2-3) was achieved in 85%. In the majority of cases complete clot removal was achieved (TICI 0, 12%; TICI 1, 2%; TICI 2a, 14%; TICI 2b, 18%; TICI 3, 53%). The median number of deployments was 2 (range 1-6). Twelve procedural complications (10%) occurred.

Conclusions: The Aperio thrombectomy device seems to be an effective and adequately safe tool for reopening occluded cerebral arteries in the setting of acute stroke.
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http://dx.doi.org/10.1136/neurintsurg-2015-011678DOI Listing
August 2016

Multivariate dynamic prediction of ischemic infarction and tissue salvage as a function of time and degree of recanalization.

J Cereb Blood Flow Metab 2015 Sep 8;35(9):1397-405. Epub 2015 Jul 8.

Department of Diagnostic and Interventional Neuroradiology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.

Benefit of endovascular recanalization beyond established treatment time windows likely exists in select stroke patients. However, there is currently no imaging model that predicts infarction adjusting for elapsed time between the pathologic snapshot of admission imaging until endovascular recanalization. We trained and cross validated a multivariate generalized linear model (GLM) that uses computer tomography perfusion and clinical data to quantify patient-specific dynamic change of tissue infarction depending on degree and time of recanalization. Multicenter data of 161 patients with proximal anterior circulation occlusion undergoing endovascular therapy were included. Multivariate voxelwise infarct probability was calculated within the GLM. The effect of increasing time to treatment and degree of recanalization on voxelwise infarction was calculated in each patient. Tissue benefit of successful relative to unsuccessful recanalization was shown up to 15 hours after onset in individual patients and decreased nonlinearly with time. On average, the relative reduction of infarct volume at the treatment interval of 5 hours was 53% and this salvage effect decreased by 5% units per hour to <5% after 10 additional hours to treatment. Treatment time-adjusted multivariate prediction of infarction by perfusion and clinical status may identify patients who benefit from extended time to recanalization therapy.
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http://dx.doi.org/10.1038/jcbfm.2015.144DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4640330PMC
September 2015

The Pattern of Brain Microhemorrhages After Severe Lung Failure Resembles the One Seen in High-Altitude Cerebral Edema.

Crit Care Med 2015 Sep;43(9):e386-9

1Department of Anesthesiology, Emergency and Intensive Care Medicine, University Medical Center Göttingen, Göttingen, Germany. 2Department of Diagnostic and Interventional Neuroradiology, University Medical Center Göttingen, Göttingen, Germany. 3Division of Sports Medicine, Department of Internal Medicine, Medical Clinic, University Hospital Heidelberg, Heidelberg, Germany.

Objectives: After suffering from severe acute respiratory distress syndrome, several patients show generalized brain alterations and atrophy. A distinctive morphologic pattern of cerebral injury, however, has not been found so far.

Data Sources: We present the history of three patients who survived severe acute respiratory distress syndrome. In these patients, MRI of the brain showed multiple microhemorrhages predominantly in the splenium of the corpus callosum. An identical pattern of microhemorrhages has previously been described in mountaineers who suffered from high-altitude cerebral edema.

Conclusions: This report demonstrates that patients after treatment for acute respiratory distress syndrome and high-altitude cerebral edema show congruent cerebral injuries. Further investigation into the similarities of the causative conditions and neurologic consequences might reveal underlying pathophysiologic mechanisms and clinical implications of this observation.
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http://dx.doi.org/10.1097/CCM.0000000000001150DOI Listing
September 2015

Thrombectomy in patients ineligible for iv tPA (THRILL).

Int J Stroke 2015 Aug 4;10(6):950-5. Epub 2015 Jun 4.

Neurology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.

Rationale: A relevant proportion of patients with acute ischemic stroke are ineligible for intravenous thrombolysis with recombinant tissue plasminogen activator. Mechanical thrombectomy offers a treatment alternative for these patients; however, only few data are available on its safety and efficacy.

Aims And/or Hypothesis: The aim of this study was to compare safety and efficacy of stent retrievers as device class with best medical care alone in acute stroke patients with large intracranial vessel occlusion in the anterior circulation who are not eligible for intravenous thrombolysis with recombinant tissue plasminogen activator up to eight-hours of symptom onset.

Design: 'Thrombectomy in patients ineligible for iv tPA' is a prospective, open-label, blinded end-point, binational (Germany and Austria), two-arm, randomized, controlled, post-market study.

Study Outcome(s): Primary end-point is the modified Rankin Score shift analysis 90 days (±14) after stroke. Secondary end-points are excellent neurological outcomes (modified Rankin Score ≤ 1), good neurological outcomes (modified Rankin Score ≤ 2 or National Institutes of Health Stroke Scale improvement ≥ 10), difference between predicted infarct volume and actual core infarct volume (computed tomography or magnetic resonance imaging) at 30 (±6) h post-ictus, successful recanalization (thrombolysis in cerebral infarction score 2b or 3), functional health status 90 (±14) days after stroke (European Quality of Life-5 Dimensions) as well as common safety end-points (adverse event, serious adverse event, symptomatic intracranial haemorrhage at 30 (±6) h, death, or dependency).

Discussion: Whether mechanical thrombectomy in patients with acute ischemic stroke who are not eligible for intravenous thrombolysis with recombinant tissue plasminogen activator improves clinical outcomes is unclear. 'Thrombectomy in patients ineligible for iv tPA' may change clinical practice by providing evidence of an effective and safe treatment for such patients.
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http://dx.doi.org/10.1111/ijs.12527DOI Listing
August 2015