Annika Kowoll
Ruhr University Bochum
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Featured researches published by Annika Kowoll.
Journal of NeuroInterventional Surgery | 2016
Annika Kowoll; Anushe Weber; Anastasios Mpotsaris; Daniel Behme; Werner Weber
Introduction Over the past decade, endovascular techniques for the treatment of acute ischemic stroke have emerged significantly. However, revascularization rates are limited at approximately 80%, and mechanical thrombectomy procedures still last about 1 h. Therefore, we investigated the novel direct aspiration first pass technique for its efficacy and safety. Methods Our neurointerventional database was screened for patients who received mechanical thrombectomy for acute ischemic stroke using the Penumbra 5MAX ACE aspiration catheter on an intention to treat basis between November 2013 and June 2014. Procedural data, including modified Thrombolysis in Cerebral Infarction (mTICI) score, procedural timings, and complications, as well as clinical data at admission and discharge, were analyzed. Results 54 patients received mechanical thrombectomy using the 5MAX ACE. Median age was 69 (39–94) years (54% were men). Baseline National Institutes of Health Stroke Scale (NIHSS) score was 15 (2–27) and 44/54 (81%) patients received intravenous thrombolysis. Vessel occlusion sites were 91% anterior circulation and 9% posterior circulation. A successful revascularization result (mTICI ≥2b) was achieved in 93% of cases whereas direct aspiration alone was successful in 30/54 (56%) cases; among these, median time from groin puncture to revascularization was 30 min (9–113). Symptomatic intracranial hemorrhage occurred in 2/54 (4%) patients, and embolization to new territories in 3/54 (6%). Median NIHSS at discharge was 6 (0–24); 46% of patients were independent at discharge. Conclusions The direct aspiration first pass technique proofed to be fast, effective, and safe. Promising revascularization results can be achieved quickly in more than 50% of patients using this technique as the firstline option. Nevertheless, stent retrievers are still warranted in approximately 40% of cases to achieve a favorable revascularization result.
European Journal of Haematology | 2010
Roland Schroers; Alexander Baraniskin; Christoph Heute; Matthias Vorgerd; Anna Brunn; Jan Kuhnhenn; Annika Kowoll; Andriy Alekseyev; Wolff Schmiegel; Uwe Schlegel; Martina Deckert; Hendrik Pels
Reliable detection of leptomeningeal disease has the potential of facilitating the diagnosis of central nervous system (CNS) lymphoma and is important for therapeutic considerations. Currently, the standard diagnostic procedure for the detection of lymphoma in the cerebrospinal fluid is cytopathology. To improve the limited specificity and sensitivity of cytopathology, flow cytometry has been suggested as an alternative. Here, we evaluated multi‐parameter flow cytometry in combination with conventional cytopathology in cerebrospinal fluid (CSF) samples from 30 patients with primary CNS lymphoma and seven patients with secondary CNS lymphoma. Overall, in 11 of 37 (29.7%) patients with CNS lymphoma, lymphoma cells were detected in CSF by flow cytometry, while cytopathology was less sensitive displaying unequivocally malignant CSF cells in only seven of all 37 (18.9%) patients. Six (16.2%) patients showed cytopathological results suspicious of lymphoma; however, in only one of these patients, the diagnosis of CSF lymphoma cells could be confirmed by flow cytometry. In primary CNS lymphomas (PCNSL), seven of 30 (23.3%) patients were positive for CSF lymphoma cells in flow cytometry, in contrast to four (13.3%) patients with PCNSL with definitely positive cytopathology. In summary, our results suggest that multi‐parameter flow cytometry increases the sensitivity and specificity of leptomeningeal disease detection in CNS lymphomas. Both methods should be applied concurrently for complementary diagnostic assessment in patients with CNS lymphoma.
Journal of NeuroInterventional Surgery | 2015
Daniel Behme; Anushe Weber; Annika Kowoll; A. Berlis; Thomas H Burke; Werner Weber
Background and purpose The focus of this study was to determine ease of deployment, safety and effectiveness of the LVIS Jr device. Methods A retrospective analysis was performed of 32 cases comprising 34 aneurysms in which the LVIS Jr device was used for stent-assisted coil embolization of intracranial aneurysms from February to October 2012, including all clinical and angiographic data as well as mid-term follow-up (1–12 months of treatment). Results The median age of the patients was 54 years (range 21–76) and 19 (59%) were women. The aneurysms were ruptured in 12/34 cases (35.3%); 26 (76.4%) were located within the anterior circulation and the remaining 8 (23.5%) were located in the posterior circulation. Eleven of the 34 aneurysms (32.3%) were treated with a Y-stent configuration. Immediate total occlusion was observed in 16/34 (47%), near total occlusion (90–95%) in 5/34 (14.7%) and a ‘dog ear’ or subtotal occlusion in 12/34 (35.2%). A single aneurysm was treated without coil embolization. Complications occurred in 5/34 cases (15%), including two cases of in-stent thrombosis. Conclusions Implantation of the LVIS Jr device as a support device for stent-assisted coil embolization seems to be safe and effective. The LVIS Jr device can also be implanted in a Y-stent configuration, offering a novel technique with a potentially lower risk of thromboembolic complications compared with other devices.
American Journal of Neuroradiology | 2015
Daniel Behme; Anastasios Mpotsaris; P. Zeyen; Marios-Nikos Psychogios; Annika Kowoll; C.J. Maurer; F. Joachimski; Jan Liman; Katrin Wasser; Christoph Kabbasch; A. Berlis; Michael Knauth; Thomas Liebig; Werner Weber
BACKGROUND AND PURPOSE: Several small case series reported a favorable clinical outcome for emergency stent placement in the extracranial internal carotid artery combined with mechanical thrombectomy in acute stroke. The rate of postinterventional symptomatic intracranial hemorrhages was reported to be as high as 20%. Therefore, we investigated the safety and efficacy of this technique in a large multicentric cohort. MATERIALS AND METHODS: The data bases of 4 German stroke centers were screened for all patients who received emergency stent placement of the extracranial internal carotid artery in combination with mechanical thrombectomy of the anterior circulation between 2007 and 2014. The primary outcome measure was the rate of symptomatic intracranial hemorrhage according to the European Cooperative Acute Stroke Study III criteria; secondary outcome measures included the angiographic revascularization results and clinical outcome. RESULTS: One hundred seventy patients with a median age of 64 years (range, 25–88 years) were treated. They presented after a median of 98 minutes (range, 52–160 minutes) with a median NIHSS score of 15 (range, 12–19). Symptomatic intracranial hemorrhages occurred in 15/170 (9%) patients; there was no statistically significant difference among groups pertaining to age, sex, intravenous rtPA, procedural timings, and the rate of successful recanalization. In 130/170 (77%) patients, a TICI score of ≥2b could be achieved. The in-hospital mortality rate was 19%, and 36% of patients had a favorable outcome at follow-up. CONCLUSIONS: Emergency stent placement in the extracranial internal carotid artery in combination with anterior circulation thrombectomy is effective and safe. It is not associated with a significantly higher risk of symptomatic intracranial hemorrhage compared with published series for mechanical thrombectomy alone.
Journal of NeuroInterventional Surgery | 2016
Daniel Behme; Annika Kowoll; Anastasios Mpotsaris; Claudia Hader; Lukas Hechelhammer; Johannes Weber; Werner Weber
Background The aim of this study was to assess reperfusion and clinical outcome of treatment with the self-expanding retrievable Separator 3D in revascularization of acute ischemic stroke. The three-dimensional (3D) device secures thrombus with direct aspiration and supports debulking of the clot. Methods At two centers, 129 consecutive stroke patients with National Institutes of Health Stroke Scale (NIHSS) scores ≥5 were treated with mechanical thrombectomy using the Separator 3D as a component of the Penumbra System within 8 h of symptom onset; modified Treatment in Cerebral Infarction (mTICI) revascularization scores, NIHSS score on admission and discharge, mortality rates, and modified Rankin Scale (mRS) outcomes at 90 days were evaluated. Results A total of 129 vessels in 129 patients were treated. Occlusions were located in the middle cerebral artery (MCA, 48%), internal carotid artery (ICA, 33%), cervical ICA–MCA (3%), and vertebrobasilar arteries (16%). Intravenous thrombolytic therapy with recombinant tissue plasminogen activator was given to 78% of patients. Median NIHSS was 15 prior to treatment. Reperfusion to mTICI 2b or 3 was successful in 96/129 (74%) target arterial lesions, with more than half of cases (51%) achieving mTICI 3. The mean time from arterial puncture to revascularization was 65 min. At 90 days, the symptomatic intracranial hemorrhage rate was 4%, all cause mortality was 32%, and 43/99 patients (43%) achieved functional independence with an mRS score of ≤2. Conclusions The results suggest that the Separator 3D enables safe and effective revascularization of occluded large arteries in acute stroke intervention, leading to a high rate of functional independence at 90 days.
Journal of Stroke & Cerebrovascular Diseases | 2016
Daniel Behme; Christoph Kabbasch; Annika Kowoll; Franziska Dorn; Thomas Liebig; Werner Weber; Anastasios Mpotsaris
AIM Several factors influence the outcome after acute ischemic stroke secondary to proximal occlusions of cerebral vessels. Among others, noneligibility for intravenous thrombolysis (IVT) and incomplete revascularization have been identified as predictors of unfavorable outcome. The aim of this study was to investigate whether concomitant IVT influences the revascularization efficacy in mechanical thrombectomy (MT). METHODS This study conducted a retrospective analysis of all consecutive patients presenting with an anterior circulation stroke due to large-artery occlusion with imaging evidence who were treated with MT between July 2012 and December 2013 at 2 high-volume stroke centers. Imaging data were regraded and re-evaluated according to the modified Treatment in Cerebral Ischemia scale and its respective vessel occlusion site definitions. Clinical end points included National Institutes of Health Stroke Scale (NIHSS) and modified Rankin Scale; imaging and procedural measures were technical end points. RESULTS We identified 93 patients who presented with an occlusion of the middle cerebral artery (MCA): of these patients, 66 (71%) received IVT. We did not find statistically significant differences in the baseline NIHSS score, time from symptom onset to groin puncture, and age when comparing the IVT group with the non-IVT group. The rate of successful recanalizations (modified Treatment in Cerebral Ischemia score ≥ 2b) was significantly higher in patients with MCA occlusion and concomitant IVT (P = .01). Stepwise logistic regression identified IVT and thrombus length as predictive factors for successful mechanical recanalization (P = .004, P = .002). CONCLUSION IVT and thrombus length are predictive factors for a successful recanalization in MT for acute ischemic stroke with underlying MCA occlusion.
Journal of NeuroInterventional Surgery | 2015
Daniel Behme; Annika Kowoll; Werner Weber; Anastasios Mpotsaris
Aims Recent recommendations on the designation of target artery lesions in acute ischemic stroke include the anatomical differentiation between a proximal and a distal occlusion site of the M1 segment of the middle cerebral artery (MCA). The aim of this study was to evaluate whether these occlusion types differ in terms of a disability-free (modified Rankin Scale (mRS) 0 or 1) clinical outcome at 90 days. Methods A retrospective analysis was performed of all patients with MCA M1 occlusions who had a successful revascularization result after mechanical thrombectomy between October 2009 and September 2013 and for whom follow-up at 90 days was available. Imaging data were regraded and re-evaluated according to the modified Thrombolysis In Cerebral Infarction (mTICI) scale and the respective vessel occlusion site definitions. Outcome measures included National Institutes of Health Stroke Scale (NIHSS), mRS, Alberta Stroke Program Early CT Score (ASPECTS) scoring and procedural timings. Results 62 patients were successfully recanalized; follow-up at 90 days was available for 42/62 patients (68%). There were proximal MCA occlusions in 24/42 patients (57%) and distal occlusions in 18/42 (43%). Baseline NIHSS, ASPECTS, procedural timings and final mTICI scores did not differ significantly between proximal and distal M1 occlusions. There was a statistically significant difference between proximal and distal M1 occlusions regarding a disability-free early outcome (mRS 0 or 1) at discharge (p=0.03) and at 90 days (p=0.04). Conclusions Proximal occlusions of the M1 segment of the MCA incorporating the lenticulostriate perforators are associated with a poorer clinical outcome than distal M1 occlusions that spare these perforators. Involvement of these perforators might become an additional predictor of clinical outcome after mechanical thrombectomy in ischemic stroke.
Journal of NeuroInterventional Surgery | 2017
Markus Möhlenbruch; Christoph Kabbasch; Annika Kowoll; E Broussalis; M Sonnberger; Marguerite Müller; Martin Wiesmann; Johannes Trenkler; M Killer-Oberpfalzer; Werner Weber; Anastasios Mpotsaris; Martin Bendszus; S Stampfl
Introduction The direct aspiration first pass technique (ADAPT) has been introduced as a rapid and safe endovascular treatment strategy in patients with ischemic stroke. Objective To determine the technical feasibility, safety, and functional outcome with ADAPT using the new large-bore 6F SOFIA Plus catheter. Methods A retrospective analysis of prospectively collected data from six university hospitals was performed. The following parameters of all acute stroke procedures (June 2015– January 2016) using the SOFIA Plus catheter were analyzed: accessibility of the thrombus with the catheter, recanalization success (Thrombolysis in Cerebral Infarction ≥2b), time to recanalization, procedure-related complications. Furthermore, National Institutes of Health Stroke Scale (NIHSS) scores at presentation and discharge and the modified Rankin scale (mRS) score at 90 days were recorded. Results 85 patients were treated using the SOFIA Plus catheter. The occlusion site was the anterior circulation in 94.1%. Median baseline NIHSS score was 18. In 64.7%, ADAPT alone was successful after a median procedure time of 21 min. With additional use of stent retrievers in the remaining cases, the recanalization rate was 96.5%. No catheter-related complications such as dissections were observed. Thrombus migration to a new vascular territory occurred in 4.7% and symptomatic hemorrhage in 4.7%. After 3 months, mRS 0–2 was achieved in 49.4%. Mortality rate was 20%. Conclusions In the majority of cases, thrombus aspiration using the SOFIA Plus catheter results in successful recanalization after a short procedure time. With additional use of stent retrievers, a high recanalization rate can be achieved (96.5%). The complication rate was in line with those of previous publications.
Journal of NeuroInterventional Surgery | 2016
S Fischer; A Weber; A Titschert; C Brenke; Annika Kowoll; Werner Weber
Purpose To retrospectively evaluate the safety and efficacy of the endovascular treatment of wide-necked intracranial aneurysms assisted by a novel intra-/extra-aneurysm stent-like implant (pCONus). Methods Initial and follow-up angiographic and clinical results are presented of 25 patients with 25 unruptured and ruptured wide-necked intracranial aneurysms treated by reconstruction of the aneurysm neck using the pCONus implant followed by coil occlusion of the fundus. Results Successful intra-/extra-aneurysm deployment of the pCONus with coil occlusion of the fundus was achieved in all but one case. Procedure-related ischemic complications were observed in three cases with permanent deterioration in one. Acceptable aneurysm occlusion was achieved in all cases. Follow-up angiography revealed sufficient occlusion in 81.0% of the aneurysms. Intimal hyperplasia in the stented segment of the parent artery or device migration has not been observed to date. Conclusions The pCONus device offers a promising treatment option for complex wide-necked bifurcation intracranial aneurysms. Acute or delayed dislocations of coils into the parent artery are successfully avoided.
GMS German Medical Science | 2011
Katrin Patrij; Marcel Reiser; Luise Wätzel; Hendrik Pels; Annika Kowoll; Ulrich Herrlinger; Andreas Engert; Michael Linnebank; Gabriele Schackert; Marlies Vogt-Schaden; Gerlinde Egerer; Monika Lamprecht; Tracy T. Batchelor; Uwe Schlegel; Ingo G.H. Schmidt-Wolf
We analyzed clinical outcome of patients with an isolated central nervous system lymphoma (CNSL) relapse after systemic non-Hodgkin’s lymphoma (NHL). All 23 patients with an isolated secondary CNSL (SCNSL) treated at two institutions from 04/2003–12/2007 were included into this analysis. At cerebral relapse, 15/23 patients were treated with a regimen consisting of high-dose methotrexate (Bonn protocol). After a median follow-up of 6.5 months (range 1–68), 15/23 (65%) patients with SCNSL had relapsed or progressed. HD (high-dose)- methotrexate (MTX) chemotherapy according to the Bonn protocol is effective concerning response rates; however, overall survival of patients with SCNSL seems to be impaired in comparison to relapses in primary CNSL (PCNSL).