Omer F. EKER

Prof. Dr. Omer F. EKER


Research Focus & Metrics

Academic Career Length

18Years (2009-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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29 March 2021 in International Journal of Stroke
Verified
Journal Article
Open access
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RNRaul G. Nogueira
Raul G. Nogueira
MAMohamad Abdalkader
Mohamad Abdalkader
MQMuhammed M. Qureshi
Muhammed M. Qureshi
MFMichael R. Frankel
Michael R. Frankel
OMOssama Yassin Mansour
Ossama Yassin Mansour
Thanh N NguyenThanh N Nguyen
Thanh N Nguyen
Background: The COVID-19 pandemic led to profound changes in the organization of health care systems worldwide. Aims: We sought to measure the global impact of the COVID-19 pandemic on the volumes for mechanical thrombectomy, stroke, and intracranial hemorrhage hospitalizations over a three-month period at the height of the pandemic (1 March–31 May 2020) compared with two control three-month periods (immediately preceding and one year prior). Methods: Retrospective, observational, international study, across 6 continents, 40 countries, and 187 comprehensive stroke centers. The diagnoses were identified by their ICD-10 codes and/or classifications in stroke databases at participating centers. Results: The hospitalization volumes for any stroke, intracranial hemorrhage, and mechanical thrombectomy were 26,699, 4002, and 5191 in the three months immediately before versus 21,576, 3540, and 4533 during the first three pandemic months, representing declines of 19.2% (95%CI, −19.7 to −18.7), 11.5% (95%CI, −12.6 to −10.6), and 12.7% (95%CI, −13.6 to −11.8), respectively. The decreases were noted across centers with high, mid, and low COVID-19 hospitalization burden, and also across high, mid, and low volume stroke/mechanical thrombectomy centers. High-volume COVID-19 centers (−20.5%) had greater declines in mechanical thrombectomy volumes than mid- (−10.1%) and low-volume (−8.7%) centers (p < 0.0001). There was a 1.5% stroke rate across 54,366 COVID-19 hospitalizations. SARS-CoV-2 infection was noted in 3.9% (784/20,250) of all stroke admissions. Conclusion: The COVID-19 pandemic was associated with a global decline in the volume of overall stroke hospitalizations, mechanical thrombectomy procedures, and intracranial hemorrhage admission volumes. Despite geographic variations, these volume reductions were observed regardless of COVID-19 hospitalization burden and pre-pandemic stroke/mechanical thrombectomy volumes.

10 March 2016 in American Journal of Neuroradiology
Verified
Journal Article
Open access
PDF file
GMG. Marnat
G. Marnat
IMI. Mourand
I. Mourand
OEOmer F. EKER
Omer F. EKER
PMP. Machi
P. Machi
CAC. Arquizan
C. Arquizan
VCV. Costalat
V. Costalat
BACKGROUND AND PURPOSE: Internal carotid artery dissection is a common cause of stroke in young adults. It may be responsible for tandem occlusion defined by a cervical steno-occlusive carotid wall hematoma associated with an intracranial large-vessel stroke. Intravenous thrombolysis is associated with a poor clinical outcome in these cases, and endovascular treatment has not been specifically evaluated to date. Our aim was to evaluate endovascular treatment technical and clinical efficiency in this specific occlusion topography, in comparison with treatment of isolated anterior circulation stroke. MATERIALS AND METHODS: As part of our ongoing prospective stroke data base started in August 2009 (Prognostic Factors Related to Clinical Outcome Following Thrombectomy in Ischemic Stroke [RECOST] Study), we analyzed all carotid artery dissection tandem occlusion strokes and isolated anterior circulation occlusions. All patients were selected for endovascular treatment according to clinical-radiologic mismatch, NIHSS ≥ 7 and DWI-ASPECTS ≥5, within 6 hours after onset. For carotid artery dissection, the revascularization procedure consisted first of distal recanalization by a stent retriever in the intracranial vessel. Following assessment of the circle of Willis, internal carotid artery stent placement was only performed in case of insufficiency. Carotid artery dissection treatment efficacy, safety, and clinical outcome were compared with the results of the isolated anterior circulation occlusion cohort. RESULTS: Two hundred fifty-eight patients with an anterior circulation stroke were analyzed, including 57 with tandem occlusions (22%); among them, 20 were carotid artery dissection–related occlusions (7.6%). The median age of patients with tandem occlusions with internal carotid dissection was 52.45 versus 66.85 years for isolated anterior circulation occlusion (P < .05); the mean initial NIHSS score was 17.53 ± 4.11 versus 17.55 ± 4.8 (P = .983). The median DWI-ASPECTS was 6.05 versus 6.64 (P = .098), and the average time from onset to puncture was 4.38 for tandem occlusions versus 4.53 hours in isolated anterior circulation occlusion (P = .704). Complication rates and symptomatic intracranial hemorrhage were comparable in both groups (5% versus 3%, P = .49). The duration of the procedure was significantly prolonged in case of tandem occlusion (80.69 versus 65.45 minutes, P = .030). Fourteen patients with carotid artery dissection (70%) had a 3-month mRS of ≤ 2, without a significant difference from patients with an isolated anterior circulation occlusion (44%, P = .2). Only 5 carotid artery dissections (25%) necessitated cervical stent placement. No early ipsilateral stroke recurrence was recorded, despite the absence of stent placement in 15 patients (75%) with carotid artery dissection. CONCLUSIONS: Mechanical endovascular treatment of carotid artery dissection tandem occlusions is safe and effective compared with isolated anterior circulation occlusion stroke therapy. Hence, a more conservative approach with stent placement only in cases of circle of Willis insufficiency may be a reliable and safe strategy.

27 October 2017 in Journal of NeuroInterventional Surgery
Verified
Journal Article
Open access
PDF file
IMIsabelle Mourand
Isabelle Mourand
EAEitan Abergel
Eitan Abergel
DMDaniel Mantilla
Daniel Mantilla
XAXavier Ayrignac
Xavier Ayrignac
TSTzvika Sacagiu
Tzvika Sacagiu
VCVincent Costalat
Vincent Costalat
Background A low baseline Alberta Stroke Programme Early CT Score (ASPECTS) is strongly associated with low rates of favorable outcome in patients with acute stroke. Objective To evaluate the efficacy and safety of revascularization therapy in patient with ASPECTS ≤5 in anterior circulation infarct. Methods We retrospectively analyzed 108 consecutive patients presenting low ASPECTS on diffusion-weighted imaging. Sixty patients were treated by mechanical thrombectomy, including 34 patients who received simultaneously intravenous thrombolysis. A control group of 48 patients not eligible for reperfusion therapy gave us a perspective on the natural history. Clinical outcome was evaluated at 90 days using the modified Rankin Scale (mRS) score. Hemicraniectomy after malignant infarction, mortality, and symptomatic intracranial haemorrhage (sICH) were also reported. Results Thrombolysis in Cerebral Infarction 2b–3 was assessed in 75% of treated patients. Reperfusion therapy led to significantly reduced disability (mRS score 0–2) at 90 days compared with the control group (30% vs 2.1%, p<0.001), hemicraniectomy (3.3% vs 22.9%, p=0.002), and death at 90 days (25% vs 47.9%, p=0.01). The sICH level was similar in treated patients and in the control group (p=0.78). Patients aged ≤70 years in the thrombectomy group had a significantly better clinical outcome than older patients (37.5% vs 10%, p=0.02), regardless of baseline characteristics or recanalization rate. Conclusions In patients with acute stroke in the anterior circulation and ASPECTS ≤5 revascularization therapy contributes to a favorable clinical outcome at 90 days, especially in patients younger than 70 years.

1 January 2022 in European Journal of Medical Genetics
Verified
Journal Article
Open access
CSClaire L. Shovlin
Claire L. Shovlin
EBE Buscarini
E Buscarini
CSC Sabbà
C Sabbà
JMJohannes J Mager
Johannes J Mager
AKA D Kjeldsen
A D Kjeldsen
SDSophie Dupuis-Girod
Sophie Dupuis-Girod
Hereditary haemorrhagic telangiectasia (HHT) is a complex, multisystemic vascular dysplasia affecting approximately 85,000 European Citizens. In 2016, eight founding centres operating within 6 countries, set up a working group dedicated to HHT within what became the European Reference Network on Rare Multisystemic Vascular Diseases. By launch, combined experience exceeded 10,000 HHT patients, and Chairs representing 7 separate specialties provided a median of 24 years' experience in HHT. Integrated were expert patients who focused discussions on the patient experience. Following a 2016-2017 survey to capture priorities, and underpinned by more than 40 monthly meetings, and new data acquisitions, VASCERN HHT generated position statements that distinguish expert HHT care from non-expert HHT practice. Leadership was by specialists in the relevant sub-discipline(s), and 100% consensus was required amongst all clinicians before statements were published or disseminated. One major set of outputs targeted all healthcare professionals and their HHT patients, and include the new Orphanet definition; Do's and Don'ts for common situations; Outcome Measures suitable for all consultations; COVID-19; and anticoagulation. The second output set span aspects of vascular pathophysiology where greater understanding will assist organ-specific specialist clinicians to provide more informed care to HHT patients. These cover cerebral vascular malformations and screening; mucocutaneous telangiectasia and differential diagnosis; anti-angiogenic therapies; circulatory interplays between anaemia and arteriovenous malformations; and microbiological strategies to counteract loss of normal pulmonary capillary function. Overall, the integrated outputs, and documented current practices, provide frameworks for approaches that augment the health and safety of HHT patients in diverse health-care settings.

29 June 2020 in Orphanet Journal of Rare Diseases
Verified
Journal Article
Open access
PDF file
OEOmer F. EKER
Omer F. EKER
EBEdoardo Boccardi
Edoardo Boccardi
Ulrich SureUlrich Sure
Ulrich Sure
MPManeesh C. Patel
Maneesh C. Patel
SASaverio Alicante
Saverio Alicante
CSClaire L. Shovlin
Claire L. Shovlin
Hereditary haemorrhagic telangiectasia (HHT) is a multisystemic vascular dysplasia inherited as an autosomal dominant trait. Approximately 10 % of patients have cerebral vascular malformations, a proportion being cerebral arteriovenous malformations (AVMs) and fistulae that may lead to potentially devastating consequences in case of rupture. On the other hand, detection and treatment related-risks are not negligible, and immediate. While successful treatment can be undertaken in individual cases, current data do not support the treatment of unruptured AVMs, which also present a low risk of bleeding in HHT patients. Screening for these AVMs is therefore controversial.Structured discussions, distinctions of different cerebrovascular abnormalities commonly grouped into an “AVM” bracket, and clear guidance by neurosurgical and neurointerventional radiology colleagues enabled the European Reference Network for Rare Vascular Disorders (VASCERN-HHT) to develop the following agreed Position Statement on cerebral screening:1) First, we emphasise that neurological symptoms suggestive of cerebral AVMs in HHT patients should be investigated as in general neurological and emergency care practice. Similarly, if an AVM is found accidentally, management approaches should rely on expert discussions on a case-by-case basis and individual risk-benefit evaluation of all therapeutic possibilities for a specific lesion.2) The current evidence base does not favour the treatment of unruptured cerebral AVMs, and therefore cannot be used to support widespread screening of asymptomatic HHT patients.3) Individual situations encompass a wide range of personal, cultural and clinical states. In order to enable informed patient choice, and avoid conflicting advice, particularly arising from non-neurovascular interpretations of the evidence base, we suggest that all HHT patients should have the opportunity to discuss knowingly brain screening issues with their healthcare provider.4) Any screening discussions in asymptomatic individuals should be preceded by informed pre-test review of the latest evidence regarding preventative and therapeutic efficacies of any interventions. The possibility of harm due to detection of, or intervention on, a vascular malformation that would not have necessarily caused any consequence in later life should be stated explicitly.We consider this nuanced Position Statement provides a helpful, evidence-based framework for informed discussions between healthcare providers and patients in an emotionally charged area.
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6 August 2014 in European Radiology
Verified
Journal Article
Closed access
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RCRoberto Luigi Cazzato
Roberto Luigi Cazzato
XBXavier Buy
Xavier Buy
OEOmer F. EKER
Omer F. EKER
TFThierry Fabre
Thierry Fabre
JPJean Palussiere
Jean Palussiere