Olivier Naggara

• MD PhD
• Interventional Neuroradiologist at Centre Hospitalier Sainte Anne

Introduction Post-hoc analysis of recent trials comparing bridging therapy to endovascular therapy (EVT) alone reported improved recanalization results with bridging therapy. It remains uncertain whether the positive effect of prior intravenous thrombolysis (IVT) is consistent across all mechanical thrombectomy first-line techniques (Aspiration, St...

Injury of the internal carotid artery (ICA), anterior cerebral artery (ACA), and middle cerebral artery (MCA) are rare but devastating complications during microsurgery of the anterior and middle cranial skull base. We systematically reviewed the current knowledge on ICA, ACA, and MCA injury during skull base microsurgery and performed a multicentr...

Objective: Many patients recruited in the Treatment of Brain Arteriovenous Malformations Study (TOBAS) are managed conservatively. The aim of this study was to monitor what happened to those patients. Methods: TOBAS comprises two randomized controlled trials and multiple prospective registries. All patients with brain arteriovenous malformations...

Background: The study aimed to compare outcomes of mechanical thrombectomy (MT) in pediatric patients with acute ischemic stroke (AIS) caused by focal cerebral arteriopathy (FCA) versus cardioembolism (CE). Methods: Data from the Save ChildS and KidClot cohorts were merged. Children with AIS because of FCA or CE that underwent MT were included....

BACKGROUND Timely revascularization in acute arterial ischemic stroke (AIS) is paramount for optimal outcomes. However, factors causing treatment delays in pediatric AIS remain understudied. We investigated determinants affecting the time from symptom onset or last-known-well to the start of recanalization treatment in pediatric AIS. METHODS We co...

Introduction Sequelae of dissection leading to a form of stenotic aneurysmal dilatation may predispose to thromboembolic stroke, and characteristic imaging findings in the setting of stroke should prompt consideration of this diagnosis. Case Description A 48-year-old woman, an active smoker and left-handed, presented with symptoms over a 3-week pe...

Purpose To evaluate performance of synthetic and real FLAIR for identifying early stroke in a multicenter cohort. Methods This retrospective study was conducted using DWI and FLAIR extracted from the Endovascular Treatment in Ischemic Stroke image registry (2017–2021). The database was partitioned into subsets according to MRI field strength and m...

KRAS gain-of-function mutations are frequently observed in sporadic arteriovenous malformations. The mechanisms underlying the progression of such KRAS-driven malformations are still incompletely understood, and no treatments for the condition are approved. Here, we show the effectiveness of sotorasib, a specific KRAS G12C inhibitor, in reducing th...

Background: The use of thrombectomy in patients with acute stroke and a large infarct of unrestricted size has not been well studied. Methods: We assigned, in a 1:1 ratio, patients with proximal cerebral vessel occlusion in the anterior circulation and a large infarct (as defined by an Alberta Stroke Program Early Computed Tomographic Score of ≤...

Background Retrospective studies suggest the superiority of first-line contact aspiration (CA) thrombectomy over stent-retriever (SR) in basilar artery occlusions (BAO). We aimed to investigate the impact of first-line mechanical thrombectomy per the occlusion level, considering differences in stroke etiology prevalence between proximal and distal...

Central nervous system (CNS) dural arteriovenous fistulas (DAVF) have been reported in PTEN‐related hamartoma tumor syndrome (PHTS). However, PHTS‐associated DAVF remain an underexplored field of the PHTS clinical landscape. Here, we studied cases with a PTEN pathogenic variant identified between 2007 and 2020 in our laboratory (n = 58), and for wh...

Introduction Evaluer le risque de rupture d'un anévrisme intracrânien non rompu (ANR) est un enjeu majeur. La présence, en IRM Haute Résolution FSET1 après injection, d'un rehaussement pariétal (RP+) semble prédire croissance et modification à court terme <2 ans. L'objectif de cette étude était d’étudier la valeur prédictive de ce signe quant à la...

Background and purpose In patients with acute ischemic stroke (AIS) treated with endovascular therapy (EVT), the association of pre-existing cerebral small vessel disease (cSVD) with symptomatic intracerebral hemorrhage (sICH) remains controversial. We tested the hypothesis that the presence of cerebral microbleeds (CMBs) and their burden would be...

Background Middle meningeal artery (MMA) embolization has been proposed as a treatment of chronic subdural hematoma (CSDH). The benefit of the procedure has yet to be demonstrated in a randomized controlled trial. We aim to assess the efficacy of MMA embolization in reducing the risk of CSDH recurrence 6 months after burr-hole surgery compared with...

Background The present study aimed to describe the clinical and ultrasound (US) long-term follow-up of patients with transient perivascular inflammation of the carotid artery (TIPIC) syndrome and the risk of recurrence. Methods We enrolled patients with a definitive diagnosis of TIPIC syndrome who were included in a retrospective multicenter study...

Objectives In patients with an unruptured intracranial aneurysm, gadolinium enhancement of the aneurysm wall is associated with growth and rupture. However, most previous studies did not have a longitudinal design and did not adjust for aneurysm size, which is the main predictor of aneurysm instability and the most important determinant of wall enh...

Background The co-occurrence of moyamoya vasculopathy and extra-optic pathway tumors is rare in neurofibromatosis type 1 (NF1), with only four cases described in the literature. Brain surgery in these patients may be challenging because of the risk of brain infarction after skin and dural incision. Given its percutaneous and minimally invasive natu...

We report a 20-year-old female patient (76 Kg/164 cm) with an extra-cardiac Fontan circulation who was referred to our institution for exertional dyspnoea and desaturation. The patient was diagnosed with a large calcified thrombus at the level of the Fontan fenestration, protruding inside the lumen of the conduit and reducing the diameter by half w...

Rationale: Oxygen is essential for cellular energy metabolism. Neurons are particularly vulnerable to hypoxia. Increasing oxygen supply shortly after stroke onset could preserve the ischemic penumbra until revascularization occurs. Aims: PROOF investigates the use of normobaric oxygen therapy (NBO) within six hours of symptom onset/notice for br...

Background: Weather conditions have been shown to influence the occurrence of cardiovascular events. We tested the hypothesis that weather parameters may be associated with variations of case volume of endovascular treatment (EVT) for acute ischemic stroke. Methods: Individual data from the ETIS (Endovascular Treatment in Ischemic Stroke) French...

Rationale. Mechanical thrombectomy (MT) has become the standard of care for patients with acute ischemic stroke secondary to large vessel occlusion (LVO) of the anterior circulation. Conversely, its benefit in patients with National Institutes of Health Stroke Scale (NIHSS) score ≤5 is unproven. Aim. To demonstrate the superiority of immediate MT p...

Background: Diffusion-weighted imaging lesion reversal (DWIR) is frequently observed after mechanical thrombectomy for acute ischemic stroke, but little is known about age-related differences and impact on outcome. We aimed to compare, in patients <80 versus ≥80 years old, (1) the effect of successful recanalization on DWIR and (2) the impact of D...

Purpose To provide recommendations for the anaesthetic and peri-operative management for thrombectomy procedure in stroke patients Design A consensus committee of 15 experts issued from the French Society of Anaesthesia and Intensive Care Medicine (Société Française d'Anesthésie et Réanimation, SFAR), the Association of French-language Neuro-Anaes...

Background: The Treatment of Brain AVMs Study (TOBAS) is an all-inclusive pragmatic study comprising 2 randomized clinical trials (RCTs). Patients excluded from RCTs are followed in parallel treatment and observation registries, allowing a comparison between RCT and registry patients. Methods: The first RCT (RCT-1) offers 1:1 randomized allocati...

Introduction Identification of treatable causes of intracranial hemorrhage (ICH) such as intracranial arteriovenous shunt is crucial to prevent recurrence. However, diagnostic approaches vary considerably across centers, partly because of limited knowledge of the diagnostic performance of first-line vascular imaging techniques. We assessed the diag...

Importance International guidelines recommend avoiding intravenous thrombolysis (IVT) in patients with ischemic stroke who have a recent intake of a direct oral anticoagulant (DOAC). Objective To determine the risk of symptomatic intracranial hemorrhage (sICH) associated with use of IVT in patients with recent DOAC ingestion. Design, Setting, and...

Background Acute intracranial large vessel occlusion (LVO) is an important cause of morbidity and mortality among children; however, unlike in adults, no clinical trial has investigated the benefit of mechanical thrombectomy (MT) in pediatric LVO. Thus, MT remains an off-label procedure for pediatric stroke.PurposeTo investigate the efficacy and sa...

Background and purpose: FLAIR vascular hyperintensities are thought to represent leptomeningeal collaterals in acute ischemic stroke. However, whether all-FLAIR vascular hyperintensities or FLAIR vascular hyperintensities-DWI mismatch, ie, FLAIR vascular hyperintensities beyond the DWI lesion, best reflects collaterals remains debated. We aimed to...

Background Intravenous thrombolysis (IVT) for patients treated with mechanical thrombectomy (MT) for proximal occlusions has recently been questioned through randomized trials. However, few patients with M2 occlusions were included. We investigated the influence of prior IVT for patients presenting M2 occlusions treated with MT in comparison with M...

Background Patients treated with acute carotid stenting (CAS) may have higher odds of a favorable outcome than those treated without CAS during thrombectomy in tandem occlusions. Antiplatelet therapy is associated with CAS to avoid stent thrombosis, which occurs in around 20% of patients and negatively impacts outcomes. In this study we compared tw...

Importance There is to date limited evidence that revascularization strategies are associated with improved functional outcome in children with acute ischemic stroke (AIS). Objectives To report clinical outcomes and provide estimates of revascularization strategy safety and efficacy profiles of intravenous thrombolysis (IVT) and/or endovascular tr...

Background and purpose To determine the influence of the cerebral small vessel disease (SVD) burden on collateral recruitment in patients treated with mechanical thrombectomy (MT) for anterior circulation acute ischemic stroke (AIS). Methods Patients with AIS due to large vessel occlusion (LVO) from the Thrombectomie des Artères Cérébrales (THRACE...

Background and purpose: Brain AVMs represent the main etiology of pediatric intracranial hemorrhage. Noninvasive imaging techniques to monitor the treatment effect of brain AVMs remain an unmet need. In a large cohort of pediatric ruptured brain AVMs, we aimed to investigate the role of arterial spin-labeling for the longitudinal follow-up during...

Background: Prior studies indicated a decrease in the incidences of aneurysmal subarachnoid haemorrhage (aSAH) during the early stages of the COVID-19 pandemic. We evaluated differences in the incidence, severity of aSAH presentation, and ruptured aneurysm treatment modality during the first year of the COVID-19 pandemic compared with the precedin...

Background: Determine if early venous filling (EVF) after complete successful recanalization with mechanical thrombectomy in acute ischemic stroke is an independent predictor of symptomatic intracranial hemorrhage (sICH) and integrate EVF into a risk score for sICH prediction. Methods: Consecutive patients with anterior acute ischemic stroke tre...

Background & purpose: Despite continuous improvement and growing knowledge in the endovascular therapy of large vessel occlusion stroke (LVOS), mechanical thrombectomy (MT) still fails to obtain satisfying intracranial recanalization in 10 to 15%. However, little is known regarding clinical and radiological outcomes among this singular underexplor...

Background: The number of mechanical thrombectomy (MT) passes is strongly associated with angiographic reperfusion as well as clinical outcomes in patients with anterior circulation ischemic stroke. However, these associations have not been analyzed in patients with basilar artery occlusion (BAO). We investigated the influence of the number of MT...

Background Endovascular treatment (EVT) for basilar artery occlusions (BAO) is associated with a higher rate of futile recanalization compared with anterior circulation procedures. We aimed to identify the incidence and predictors of poor clinical outcome despite successful reperfusion in current clinical practice. Methods We used data from the ET...

Purpose: To determine whether reversal of DWI lesions (DWIr) on the DWI-ASPECTS (diffusion weighted imaging Alberta Stroke Program CT Score) template should serve as a predictor of 90-day clinical outcome in acute ischemic stroke (AIS) patients with pretreatment diffusion-weighted imaging (DWI)-ASPECTS 0-5 treated with thrombectomy, and to determi...

Background Patients with pre-stroke disability, defined as a modified Rankin Scale (mRS) ≥3, were excluded from most trials of endovascular thrombectomy (EVT) for acute stroke. We sought to evaluate the prognostic factors associated with favorable outcome in stroke patients with known disability undergoing EVT, and the impact of successful reperfus...

Objectif Déterminer l'influence de la maladie des petites artères cérébrales (MPA) sur le recrutement des collatérales leptoméningées chez les patients traités par thrombectomie mécanique (TM) à la phase aigüe d'un AVC ischémique de la circulation antérieure. Méthodes Les patients avec occlusion des gros vaisseaux traités par TM dans l'essai clini...

Background There's to date no solid evidence that revascularization strategies improve functional outcome in children. In this study of consecutive children with AIS stroke patients treated with intravenous thrombolysis (IVT) and, or endovascular treatment (EVT) we aimed to provide up to date estimates of revascularization strategies’ safety and ef...

Background: The Transient Perivascular Inflammation of the Carotid artery (TIPIC) syndrome is presumably a very rare disease characterized by a local transient inflammation of the tissue around the carotid artery. Its pathophysiology remains unknown. We performed an updated study of TIPIC syndrome cases in the setting of a multinational collaborati...

Background Recent studies in the general stroke population treated with endovascular treatment (EVT) reported that higher pre-treatment lesional volumes were independently associated with poor neurological outcome and functional dependence after stroke. However, it has been not evaluated in older patients. Aim We test the association between the p...

Background Early neurological deterioration (END) after endovascular treatment (EVT) in patients with anterior circulation acute ischemic stroke (AIS) is associated with poor outcome. END may remain unexplained by parenchymal hemorrhage (UnEND). We aim to analyze the risk factors of UnEND in the medical management (MM) and EVT arms of the HERMES st...

Background: The Transient Perivascular Inflammation of the Carotid artery (TIPIC) syndrome is presumably a very rare disease characterized by a local transient inflammation of the tissue around the carotid artery. Its pathophysiology remains unknown. We performed an updated study of TIPIC syndrome cases in the setting of a multinational collaborati...

Background: Safety and efficacy of recanalization treatments, i.e. intravenous thrombolysis (IVT) and/or mechanical thrombectomy (MT), have to be refined in pediatric stroke. Methods: The French KIDCLOT multisourcing nationwide retrospective study (NCT03887143) collected data of consecutive children aged >28 days and <18 years old with acute arteri...

Background In acute ischemic stroke (AIS), fluid-attenuated inversion recovery (FLAIR) is used for treatment decisions when onset time is unknown. Synthetic FLAIR could be generated with deep learning from information embedded in diffusion-weighted imaging (DWI) and could replace acquired FLAIR sequence (real FLAIR) and shorten MRI duration. Purpos...

Riassunto Una dissecazione arteriosa cervicale deriva dal clivaggio della parete arteriosa da parte di un ematoma che può o meno comunicare con il lume arterioso attraverso una breccia intimale. La maggior parte delle dissecazioni è spontanea o si verifica dopo un trauma cervicale minore. Esse si traducono in sintomi e segni locali (cefalee, cervic...

Background : Cerebral aspergillosis (CA) is a life-threatening disease for which diagnosis and management remain challenging. Detailed analyses from large cohorts are lacking. Methods : We included 119 cases of proven (n=55) or probable (n=64) CA diagnosed between 2006 and 2018 at 20 French hospitals. Data were collected at baseline and during fol...

Background and Purpose Procedural complications in thrombectomy for large vessel occlusions of the anterior circulation are not well described. We investigated the incidence, risk factors, and clinical implications of thrombectomy complications in daily clinical practice. Methods We used data from the ongoing prospective multicenter observational...

Objective Individualized patient selection for mechanical thrombectomy (MT) in patients with acute ischemic stroke (AIS) and large ischemic core (LIC) at baseline is an unmet need. We tested the hypothesis, that assessing the functional relevance of both the infarcted and hypo-perfused brain tissue, would improve the selection framework of patients...

The benefits of mechanical thrombectomy (MT) for patients with acute ischemic stroke (AIS) and a large ischemic core (LIC) at presentation are uncertain. We aimed to obtain up-to-date aggregate estimates of the outcomes following MT in patients with volumetrically assessed LIC. We conducted a Preferred Reporting Items for Systematic reviews and Met...

Background Recurrence following obliteration of brain arteriovenous malformations (AVMs) is common in children surgically treated, but recurrences following endovascular (EVT) and radiosurgical approaches are scantily reported. Objective To analyze the rates and risk factors for AVM recurrence after obliteration in a single-center cohort of childr...

Background and Purpose The influence of prior antiplatelet therapy (APT) uses on the outcomes of patients with acute ischemic stroke treated with endovascular therapy is unclear. We compared procedural and clinical outcomes of endovascular therapy in patients on APT or not before stroke onset. Methods We analyzed 2 groups from the ongoing prospect...

Background and Purpose Pediatric nontraumatic intracerebral hemorrhage accounts for half of stroke in children. Early diagnostic of the causative underlying lesion is the first step toward prevention of hemorrhagic recurrence. We aimed to investigate the performance of arterial spin labeling sequence (ASL) in the acute phase etiological workup for...

Background Despite constant improvements in recent years, sufficient reperfusion after mechanical thrombectomy (MT) is not reached in up to 15% of patients with large vessel occlusion stroke (LVOS). The outcome of patients with unsuccessful reperfusion after MT especially after intravenous thrombolysis (IVT) use is not known. We investigated the in...

Introduction Les études antérieures sur la mucormycose du système nerveux central (SNC) sont basées sur des cas rapportés ou des cohortes de petits effectifs. Elles manquent de données cliniques et biologiques précises. Des études supplémentaires sont nécessaires pour guider les cliniciens, car la mucormycose du SNC nécessite un diagnostic rapide....

Background and Purpose We aimed to evaluate among trained interventional neuroradiologist, whether increasing individual experience was associated with an improvement in mechanical thrombectomy (MT) procedural performance metrics. Methods Individual MT procedural data from 5 centers of the Endovascular Treatment in Ischemic Stroke registry and 2 a...

Machine Learning (ML) has been proposed for tissue fate prediction after acute ischemic stroke (AIS), with the aim to help treatment decision and patient management. We compared three different ML models to the clinical method based on diffusion-perfusion thresholding for the voxel-based prediction of final infarct, using a large MRI dataset obtain...

Objective To determine whether the association between increasing number of clot retrieval attempts (CRA) and unfavorable outcome is due to an increase in emboli to new territory (ENT) and greater infarct growth (IG) in successfully recanalized patients with acute ischemic stroke due to large vessel occlusion (AIS LVO). Methods Data were extracted...

Background Studies have suggested that collateral status modifies the effect of successful reperfusion on functional outcome after endovascular therapy (EVT). We aimed to assess the association between collateral status and EVT outcomes and to investigate whether collateral status modified the effect of successful reperfusion on EVT outcomes. Meth...

Recent studies of the medical literature have revealed numerous and serious problems. Errors in the design, methods and interpretation of studies can frequently be identified. A huge hidden problem is publication bias, the tendency for positive articles to be published, while negative articles are either not written or submitted. This can systemati...

Background The predictors of successful reperfusion and the effect of reperfusion after endovascular treatment (EVT) for M2 occlusions have not been well studied. We aimed to identify predictors of successful reperfusion and the effect of reperfusion on outcomes of EVT for M2 occlusions in current practice. Methods Patients with acute ischemic str...

Background The best recanalization strategy for mechanical thrombectomy (MT) remains unknown as no randomized controlled trial has simultaneously evaluated first-line stent retriever (SR) versus contact aspiration (CA) versus the combined approach (SR+CA). Objective To compare the efficacy and safety profiles of SR, CA, and SR+CA in patients with...

OBJECTIVE The clinical outcome of pediatric intracerebral hemorrhage (pICH) is rarely reported in a comprehensive way. In this cohort study, systematic review, and meta-analysis of patients with pICH, the authors aimed to describe the basic clinical outcomes of pICH. METHODS Children who received treatment for pICH at the authors’ institution were...

Purpose Brain arteriovenous malformations (bAVM) are the main cause of pediatric intracerebral hemorrhage (pICH). Embolization with Onyx (ev3, Irvine, CA, USA) in children with ruptured bAVM has been infrequently reported. The aim of this study was to assess the safety and efficacy profile of Onyx embolization as first line endovascular treatment o...

OBJECTIVE Understanding the etiological spectrum of nontraumatic pediatric intracerebral hemorrhage (pICH) is key to the diagnostic workup and care pathway. The authors aimed to evaluate the etiological spectrum of diseases underlying pICH. METHODS Children treated at the authors’ institution for a pICH were included in an inception cohort initiat...

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Although the left ventricular assist device is an important bridge to heart transplantation for patients with end-stage heart failure, it can also be a source of embolic stroke. We present a case of late intracranial mechanical thrombectomy performed for embolic stroke beyond the recommended 6 h, thus allowing for heart transplantation 4 days after...

OBJECTIVE Rupture of brain arteriovenous malformation (AVM) is the main etiology of intracerebral hemorrhage (ICH) in children. Ensuing intracranial hypertension is among the modifiable prognosis factors and sometimes requires emergency hemorrhage evacuation (HE). The authors aimed to analyze variables associated with HE in children with ruptured A...

Background and Purpose Significant hemorrhage expansion (sHE) is a known predictor of poor outcome after an intracerebral hemorrhage (ICH) in adults but remains poorly reported in children. In a large inception cohort, we aimed to explore the prevalence of sHE, its associations with clinical outcomes, and its clinical-imaging predictors in children...

No controlled pharmacological studies are available in the field of pediatric stroke, except for sickle cell disease. Therefore, while pharmacological and mechanical recanalization treatments have repeatedly shown clinical benefit in adults with arterial ischemic stroke, pediatric strokologists still cannot base their therapeutic management (includ...

Rupture of an intracranial aneurysm leads to subarachnoid hemorrhage, a severe type of stroke. To discover new risk loci and the genetic architecture of intracranial aneurysms, we performed a cross-ancestry, genome-wide association study in 10,754 cases and 306,882 controls of European and East Asian ancestry. We discovered 17 risk loci, 11 of whic...

Rupture of an intracranial aneurysm leads to subarachnoid hemorrhage, a severe type of stroke. To discover new risk loci and the genetic architecture of intracranial aneurysms, we performed a cross-ancestry, genome-wide association study in 10,754 cases and 306,882 controls of European and East Asian ancestry. We discovered 17 risk loci, 11 of whic...

Background and purpose: Collateral status and thrombus length have been independently associated with functional outcome in patients with acute ischemic stroke. It has been suggested that thrombus length would influence functional outcome via interaction with the collateral circulation. We investigated the individual and combined effects of thromb...

Abstract Background One quarter to one third of patients eligible for systemic thrombolysis are on antiplatelet therapy at presentation. In this study, we aimed to assess the safety and efficacy of intravenous thrombolysis in stroke patients on prescribed antiplatelet therapy in the WAKE-UP trial. Methods WAKE-UP was a multicenter, randomized, doub...

Résumé Introduction Les kystes osseux anévrysmaux (KOA) sont des lésions osseuses bénignes de l’enfant et de l’adolescent qui peuvent présenter un pouvoir agressif local avec un risque fracturaire et dont la nature et le traitement restent, encore aujourd’hui, discutés. Le but de cette étude est de vérifier l’efficacité, la simplicité et la bonne...

Background Patients who have had a stroke with unknown time of onset have been previously excluded from thrombolysis. We aimed to establish whether intravenous alteplase is safe and effective in such patients when salvageable tissue has been identified with imaging biomarkers. Methods We did a systematic review and meta-analysis of individual pati...

Background and purpose: Whether architectural characteristics of ruptured brain AVMs vary across the life span is unknown. We aimed to identify angioarchitectural features associated with brain AVMs ruptured early in life. Materials and methods: Patients with ruptured brain AVMs referred to 2 distinct academic centers between 2000 and 2018 were...