Treatment of intracranial dural fistulas with Onyx : a prospective cohort, systematic review, and meta-analysis

BACKGROUND Onyx is important embolic material in the endovascular treatment of intracranial dural arteriovenous fistula (DAVF). However, its impact on DAVF occlusion rates, morbidity, mortality, and complication rates is not fully examined. OBJECTIVE To improve understanding of safety and effectiveness profiles associated with transarterial endovascular treatment using Onyx for intracranial DAVF METHODS We analyzed data from our prospective clinical registry and conducted a systematic review of all previous transarterial embolization studies using Onyx published between January 2005 and December 2015 in MEDLINE and EMBASE. RESULTS In the prospective study, 41 transarterial procedures were performed in 33 consecutive patients harboring 36 DAVFs. Complete initial exclusion was obtained in 32 of 36 (88.9%) fistulas; 31 fistulas were followed up showing 4 (12.9%) recurrences. Procedure-related morbidity and mortality were 3% and 0%, respectively. The literature review identified 19 studies involving a total of 425 patients with 463 DAVFs. Meta-analysis, including our registry data, showed an initial complete occlusion rate of 82% (95% confidence interval [CI]: 74%, 88%; I2, 70.6%), and recurrence rate at midterm of 2% (95% CI: 0%, 5%; I2, 21.5%). Pooled postoperative neurological deficit, procedure-related morbidity, and mortality rates were 4% (95% CI: 2%, 6%; I2, 0%), 3% (95% CI: 1%, 5%; I2, 0%), and 0%, respectively. CONCLUSION This meta-analysis suggests that transarterial embolization with Onyx is a safe treatment modality for DAVFs. Although Onyx showed a low recurrence rate at midterm, the long-term risk is poorly addressed in our study and should warrant a longer follow-up

Parameter transferability under changing climate: case study with a land surface model in the Durance watershed, France

International audienceIn physically-based land surface models, the parameters can all be prescribed a priori but calibration can be used to enhance the realism of the simulations in well instrumented domains. In such a case, the transferability of calibrated parameters under non-stationary conditions needs to be addressed, especially in the context of climate change. To this end, we used the Catchment Land Surface Model (CLSM) in the Upper Durance watershed located in the French Alps, which experienced a significant increase in temperature over the last century. The CLSM is forced by a 50-year meteorological dataset of good quality. Four parameters of the CLSM (one related to snow processes and three to soil properties) are calibrated against discharge observations with a multi-objective algorithm. First, the robustness of the CLSM parameterizations is tested by the Differential Split Sample Test (DSST). The simulations show good performances over a wide range of retrospective climatic conditions, except when the parameters are calibrated over a period with a large contribution of snowmelt to annual mean discharge. Then, the use of a climate change scenario reveals that the parameterizations of soil moisture processes in the CLSM are responsible for an increasing dispersion among simulations when facing dry and warm conditions. However, the differences between the simulated changes of river discharge remain very small. This work shows that calibration conveys some uncertainties, but they are moderate in the studied case, and pertain to the most conceptual parameterizations of this physically-based model

Introducing hysteresis in snow depletion curves to improve the water budget of a land surface model in an Alpine catchment

International audienceThe Durance watershed (14 000 km2 ), located in the French Alps, generates 10% of French hydro-power and provides drinking water to 3 million people. The Catchment Land Surface Model (CLSM), a distributed land surface model (LSM) with a multilayer, physically-based snow model, has been applied in the upstream part of this watershed where snowfall accounts for 50% of the precipitation. The CLSM subdivides the upper Durance watershed, where elevations range from 800 m to 4000 m within 3580 km2 , into elementary catchments with an average area of 500 km2 . We first show the difference between the dynamics of the accumulation and ablation of the snow cover using MODIS images and snow depth measurements. The extent of snow cover increases faster during accumulation than during ablation because melting occurs at preferential locations. This difference corresponds to the presence of a hysteresis in the snow cover depletion curve of these catchments, and we adapted the CLSM by implementing such a hysteresis in the snow cover depletion curve of the model. Different simulations were performed to assess the influence of the parameterizations on the water budget and the evolution of the extent of the snow cover. Using 6 gauging stations, we demonstrate that introducing a hysteresis in the snow cover depletion curve improves melting dynamics. We conclude that our adaptation of the CLSM contributes to a better representation of snowpack dynamics in a LSM that enables mountainous catchments to be modeled for impact studies such as those of climate change

Nitrate isotopic data from snow collected along the CHICTABA traverse, East Antarctica, 2013-2014

This dataset contains isotopic ratios of nitrate analyzed from snow samples collected along the CHICTABA traverse in East Antarctica in Nov 2013-Jan 2014. Supplemental information on the elevation (doi:10.5194/tc-13-665-2019) and surface mass balance changes (doi:10.5194/tc-13-281-2019) along the traverse route are also included for context. The samples came from relatively shallow depths of the snowpack (maximum = 2.03 m deep) and represent nitrate deposition that occurred from 0-6 years ago. These samples were collected in order to better understand the interaction and mass transfer of nitrate at the snow-air interface in Antarctica, with particular focus on determining the impacts of photolysis on nitrate. Snow samples were collected with three techniques: skin layer samples of the loose snow grains 2-6 mm deep on the snow surface, 1 m depth layer samples taken as a 5-10 cm thick layer from 1 m below the snow surface, and snow pits that extended 99-203 cm deep and were sampled at 3 cm continuous intervals. 250-1500 g of snow were collected into clean plastic bags, melted at room temperature at Concordia Station, Dome C, and then the nitrate was concentrated using an ionic exchange resin. Nitrate concentrations were determined using colorimetry. Isotopic analysis occurred at the Institut des Géosciences de l'Environnement, Grenoble, France, through bacterial denitrification and a MAT 253 mass spectrometer with Gas Bench

Multi-year record of atmospheric mercury at Dumont d'Urville, East Antarctic coast: continental outflow and oceanic influences

International audienceUnder the framework of the Global Mercury Observation System (GMOS) project, a 3.5-year record of atmospheric gaseous elemental mercury (Hg(0)) has been gathered at Dumont d'Urville (DDU, 66 • 40 S, 140 • 01 E, 43 m above sea level) on the East Antarctic coast. Additionally, surface snow samples were collected in February 2009 during a traverse between Concordia Station located on the East Antarctic plateau and DDU. The record of atmospheric Hg(0) at DDU reveals particularities that are not seen at other coastal sites: a gradual decrease of concentrations over the course of winter, and a daily maximum concentration around midday in summer. Additionally, total mercury concentrations in surface snow samples were particularly elevated near DDU (up to 194.4 ng L −1) as compared to measurements at other coastal Antarctic sites. These differences can be explained by the more frequent arrival of inland air masses at DDU than at other coastal sites. This confirms the influence of processes observed on the Antarctic plateau on the cycle of atmospheric mercury at a continental scale, especially in areas subject to recurrent katabatic winds. DDU is also influenced by oceanic air masses and our data suggest that the ocean plays a dual role on Hg(0) concentrations. The open ocean may represent a source of atmospheric Hg(0) in summer whereas the sea-ice surface may provide reactive halo-gens in spring that can oxidize Hg(0). This paper also discusses implications for coastal Antarctic ecosystems and for the cycle of atmospheric mercury in high southern latitudes

Multi-year record of atmospheric mercury at Dumo d’Urville, East Antarctic coast: continental outflow and oceanic influences

Abstract. Under the framework of the Global Mercury Observation System (GMOS) project, a 3.5-year record of atmospheric gaseous elemental mercury (Hg(0)) has been gathered at Dumont d’Urville (DDU, 66°40’S, 140°01’E, 43 m above sea level) on the East Antarctic coast. Additionally, surface snow samples were collected in February 2009 during a traverse between Concordia Station located on the East Antarctic plateau and DDU. The record of atmospheric Hg(0) at DDU reveals particularities that are not seen at other coastal sites: a gradual decrease of concentrations over the course of winter, and a daily maximum concentration around midday in summer. Additionally, total mercury concentrations in surface snow samples were particularly elevated near DDU (up to 194.4 ng L−1) as compared to measurements at other coastal Antarctic sites. These differences can be explained by the more frequent arrival of inland air masses at DDU than at other coastal sites. This confirms the influence of processes observed on the Antarctic plateau on the cycle of atmospheric mercury at a continental scale, especially in areas subject to recurrent katabatic winds. DDU is also influenced by oceanic air masses and our data suggest that the ocean plays a dual role on Hg(0) concentrations. The open ocean may represent a source of atmospheric Hg(0) in summer whereas the sea-ice surface may provide reactive halogens in spring that can oxidize Hg(0). </jats:p

Nitrate chemistry of snow samples collected along the CHICTABA transect, East Antarctica, 2013-2014

Nitrate samples were originally collected as 0.2-1.5 kg snow samples in the field along the CHICTABA traverse, Antarctica. Snow was collected in three methods: snow pits, skin layer, and 1 m depth layer. For snow pits, snow was collected in increments of 3 cm thick layers. Skin layer samples were collected as the loose snow grains 2-6 mm deep on the surface. The 1 m depth layer samples were taken as a 5-10 cm thick layer surrounding 1 m depth, which was then thoroughly mixed. Samples were melted and nitrate concentrated with a ion exchange resin at Concordia Station, Antarctica. Isotopic analysis performed with MAT253 mass spectrometer at IGE, Grenoble, France

Embolization of ruptured pancreaticoduodenal arcade aneurysms due to median arcuate ligament without celiac artery revascularization: a single-center experience and literature review

Abstract Background The aim of this single-center retrospective study is to evaluate the feasibility, complications, and outcomes of transarterial embolization (TAE) for ruptured pancreaticoduodenal arcades aneurysms (PDAAs) due to median arcuate ligament (MAL), without subsequent revascularization of celiac artery (CA) occlusion/stenosis. Methods Between January 1st 2012 and June 1st 2024, all records from adult patients (≥ 18 years old) referred to our hospital for TAE due to ruptured PDAAs were retrospectively reviewed. All referrals were based on emergency clinical decisions and computed tomography. Procedure data included procedure, type of embolic agent and per-procedural complication. TAE technical success was defined as the cessation of aneurysm opacification immediately after the TAE, based on angiographic findings. Overall technical success was defined as the cessation of aneurysm opacification after TAE or percutaneous salvage approach during the same session. Then, we analyzed all published original articles published between January 2007 and December 2024 on emergency TAE of ruptured PDAAs due to MAL, without subsequent treatment of CA stenosis/occlusion. Results Nine patients (4 males) were referred for TAE for ruptured PDAAs due to MAL in our center. TAE technical success was achieved in 7/9 patients, and overall technical success was achieved in all patients. There were no major complications. No patients had rebleeding during follow-up. We reviewed four retrospective studies including 29 patients treated for ruptured PDAAs due to MAL without subsequent treatment of CA stenosis/occlusion. No patient received additional treatment for CA stenosis/occlusion. No aneurysm recurrence was diagnosed during the reported follow-up periods ranging from 1 to 65 months. Conclusion TAE for ruptured PDAAs without CA revascularization is safe and should be considered, although further studies are required to validate its validity and long-term outcomes