Endovascular Treatment of Atherosclerotic Tandem Occlusions in Anterior Circulation Stroke: Technical Aspects and Complications Compared to Isolated Intracranial Occlusions

Background and Purpose: Endovascular treatment of tandem occlusions is an emerging option. We describe our multicenter experience with endovascular management of atherosclerotic tandem occlusions in the anterior circulation, particularly the technical aspects and complications in comparison to isolated intracranial occlusions.Materials and Methods: Consecutive patients with tandem occlusions due to atherosclerotic causes who underwent mechanical thrombectomy at two major stroke centers between January 2010 and September 2015 were reviewed. Clinical data, procedural aspects, recanalization rates, complication rates, and clinical outcome were analyzed and compared to findings in patients with isolated intracranial occlusions.Results: One hundred and twenty-one patients with tandem occlusions and 456 patients with isolated intracranial occlusions (carotid-T/M1) were included. Mean intervention time was faster (33 min vs. 57 min, p < 0.001) and recanalization success was higher (TICI 2b/3 83.6 vs. 70.2%, p = 0.002) in patients with isolated occlusions. No difference was seen in clinical outcome and complications, except for a higher rate of asymptomatic hemorrhage in the tandem group (29.8 vs. 17.1%, p = 0.003). Choice of recanalization approach (antegrade vs. retrograde) in the tandem group made no difference, except for a trend toward less distal emboli using the retrograde approach (4.0 vs. 13.0%, p = 0.082). Stenting of the extracranial internal carotid artery (ICA) was performed in 81%, PTA alone in 7.4%, and deferred stenting in 11.6%. Rate of stent/ICA occlusion within 7 days was 10.3% after stenting and 33.3% after PTA (p = 0.127). In the tandem group, age (p = 0.034), National Institutes of Health Stroke Scale score (NIHSS) at admission (p = 0.002), recanalization rate (p < 0.001), complications (p = 0.016), and symptomatic intracranial hemorrhage (sICH) (p = 0.001) were associated with poor outcome, whereas extracranial treatment modality and stent/ICA occlusion within 7 days did not affect outcome.Conclusion: Endovascular treatment of tandem occlusions is technically feasible, achieves recanalization rates and rates of good clinical outcome comparable to those in patients with isolated intracranial occlusions. Following acute ICA stenting, the risk of stent occlusion and sICH appeared to be low, but was associated with an increased rate of asymptomatic ICH

Time to treatment with bridging intravenous alteplase before endovascular treatment:subanalysis of the randomized controlled SWIFT-DIRECT trial.

BACKGROUND We hypothesized that treatment delays might be an effect modifier regarding risks and benefits of intravenous thrombolysis (IVT) before mechanical thrombectomy (MT). METHODS We used the dataset of the SWIFT-DIRECT trial, which randomized 408 patients to IVT+MT or MT alone. Potential interactions between assignment to IVT+MT and expected time from onset-to-needle (OTN) as well as expected time from door-to-needle (DTN) were included in regression models. The primary outcome was functional independence (modified Rankin Scale (mRS) 0-2) at 3 months. Secondary outcomes included mRS shift, mortality, recanalization rates, and (symptomatic) intracranial hemorrhage at 24 hours. RESULTS We included 408 patients (IVT+MT 207, MT 201, median age 72 years (IQR 64-81), 209 (51.2%) female). The expected median OTN and DTN were 142 min and 54 min in the IVT+MT group and 129 min and 51 min in the MT alone group. Overall, there was no significant interaction between OTN and bridging IVT assignment regarding either the functional (adjusted OR (aOR) 0.76, 95% CI 0.45 to 1.30) and safety outcomes or the recanalization rates. Analysis of in-hospital delays showed no significant interaction between DTN and bridging IVT assignment regarding the dichotomized functional outcome (aOR 0.48, 95% CI 0.14 to 1.62), but the shift and mortality analyses suggested a greater benefit of IVT when in-hospital delays were short. CONCLUSIONS We found no evidence that the effect of bridging IVT on functional independence is modified by overall or in-hospital treatment delays. Considering its low power, this subgroup analysis could have missed a clinically important effect, and exploratory analysis of secondary clinical outcomes indicated a potentially favorable effect of IVT with shorter in-hospital delays. Heterogeneity of the IVT effect size before MT should be further analyzed in individual patient meta-analysis of comparable trials. TRIAL REGISTRATION NUMBER URL: https://www. CLINICALTRIALS gov ; Unique identifier: NCT03192332

Impact of intracranial aneurysm on the parent vessel hemodynamic : from in vitro observation to in vivo exploration

L'anévrisme intracrânien est la prédisposition mortelle la plus fréquente chez le sujet jeune. Sa compréhension demeure limitée alors que nous assistons au développement de nouveaux traitements endovasculaires permettant le traitement d'anévrismes de plus en plus complexes. L'essentiel des études sur le sujet repose sur des séries cliniques peu informatives, l'utilisation de méthodes de simulation numérique limitées et cible presque exclusivement les phénomènes mécaniques intrasacculaires sans tenir compte des conséquences de l'anévrisme sur l'artère porteuse. In vitro, l'utilisation d'anévrismes en silicone au sein d'un simulateur cardiovasculaire a permis d'objectiver un impact de l'anévrisme sur l'écoulement au sein du vaisseau porteur caractérisé par une diminution de sa résistance. In vivo, cet effet a été objectivé et mesuré en IRM de flux par l'analyse des courbes de débit volumétrique. Le flux sanguin en aval des anévrismes était caractérisé par une démodulation systolo-diastolique avec diminution des index de résistance et de pulsatilité. Cet effet était fortement corrélé au volume de l'anévrisme. Les stents flow diverters permettaient une « reconstruction hémodynamique » mesurable du vaisseau porteur en restaurant un flux normo-modulé et des index de pulsatilité et de résistance dans les limites de la normale. Une méthode originale pour la segmentation de l'artère carotide interne en IRM en contraste de phase 2D a été proposée. Elle se base sur l'application de la Transformée de Fourier sur les images de phase et la prise en compte de la cohérence temporelle des vitesses au sein du voxel. La méthode a été caractérisée et comparée à deux méthodes de référenceIntracranial aneurysms are the most common lethal predisposition amongst young adults. Its understanding remains limited to date while the development of new innovative endovascular treatments are increasingly available and allow for the treatment of more and more complex aneurysms with a non negligeable rate of complications. Most of the previous studies on intracranial aneurysms are based on low informative clinical series and the use of limited numerical simulation methods. They almost exclusively target the intrasaccular mechanical phenomena irrespective of the changes in the parent vessel induced by the aneurysm. In vitro, the use of silicone aneurysms embedded in a cardiovascular simulator showed an impact of the aneurysm on the the parent vessel flow conditions characterized by a decrease of its resistance. In vivo, flow MRI allowed to quantify this effect by analyzing the volumetric flow rate curves. Downstream to the aneurysm, the blood flow was dampened and presents a systolic diastolic demodulation with a collapse of resistive and pulsatility indexes. This effect was strongly correlated to the aneurysm volume. The flow diverter stents allowed for a measurable « hemodynamic reconstruction » of the parent vessel by restoring a normo modulated flow, and normal resistive and pulsatility indexes. An original method for the segmentation of internal carotid artery in 2D phase contrast MRI was proposed. It is based on the application of the Fourier Transform on the phase images and by taking into account the temporal coherence of velocities within the voxel. The method was characterized and compared to two reference method

Impact de l'anévrisme intracrânien sur l'hémodynamique de l'artère porteuse : de l’observation in vitro à l’exploration in vivo

Intracranial aneurysms are the most common lethal predisposition amongst young adults. Its understanding remains limited to date while the development of new innovative endovascular treatments are increasingly available and allow for the treatment of more and more complex aneurysms with a non negligeable rate of complications. Most of the previous studies on intracranial aneurysms are based on low informative clinical series and the use of limited numerical simulation methods. They almost exclusively target the intrasaccular mechanical phenomena irrespective of the changes in the parent vessel induced by the aneurysm. In vitro, the use of silicone aneurysms embedded in a cardiovascular simulator showed an impact of the aneurysm on the the parent vessel flow conditions characterized by a decrease of its resistance. In vivo, flow MRI allowed to quantify this effect by analyzing the volumetric flow rate curves. Downstream to the aneurysm, the blood flow was dampened and presents a systolic diastolic demodulation with a collapse of resistive and pulsatility indexes. This effect was strongly correlated to the aneurysm volume. The flow diverter stents allowed for a measurable « hemodynamic reconstruction » of the parent vessel by restoring a normo modulated flow, and normal resistive and pulsatility indexes. An original method for the segmentation of internal carotid artery in 2D phase contrast MRI was proposed. It is based on the application of the Fourier Transform on the phase images and by taking into account the temporal coherence of velocities within the voxel. The method was characterized and compared to two reference methodsL'anévrisme intracrânien est la prédisposition mortelle la plus fréquente chez le sujet jeune. Sa compréhension demeure limitée alors que nous assistons au développement de nouveaux traitements endovasculaires permettant le traitement d'anévrismes de plus en plus complexes. L'essentiel des études sur le sujet repose sur des séries cliniques peu informatives, l'utilisation de méthodes de simulation numérique limitées et cible presque exclusivement les phénomènes mécaniques intrasacculaires sans tenir compte des conséquences de l'anévrisme sur l'artère porteuse. In vitro, l'utilisation d'anévrismes en silicone au sein d'un simulateur cardiovasculaire a permis d'objectiver un impact de l'anévrisme sur l'écoulement au sein du vaisseau porteur caractérisé par une diminution de sa résistance. In vivo, cet effet a été objectivé et mesuré en IRM de flux par l'analyse des courbes de débit volumétrique. Le flux sanguin en aval des anévrismes était caractérisé par une démodulation systolo-diastolique avec diminution des index de résistance et de pulsatilité. Cet effet était fortement corrélé au volume de l'anévrisme. Les stents flow diverters permettaient une « reconstruction hémodynamique » mesurable du vaisseau porteur en restaurant un flux normo-modulé et des index de pulsatilité et de résistance dans les limites de la normale. Une méthode originale pour la segmentation de l'artère carotide interne en IRM en contraste de phase 2D a été proposée. Elle se base sur l'application de la Transformée de Fourier sur les images de phase et la prise en compte de la cohérence temporelle des vitesses au sein du voxel. La méthode a été caractérisée et comparée à deux méthodes de référenc

Failure diagnostics on railway turnout systems using support vector machines

Railway turnout systems are one of the most critical pieces of equipment in railway infrastructure. Early identification of failures in turnout systems is important to obtain increased availability and safety, and reduced operating & support cost. This paper aims to develop a method to identify „drive-rod out-ofadjustment‟ failure mode, one of the most frequently observed failure modes. Support Vector Machine with Gaussian kernel is used for classification. In addition, results of feature selection with statistical t-test and feature reduction with principal component analysis are compared in the paper.Godkänd; 2010; 20100824 (ysko

ON THE DERIVATION OF A NEW ONE-DIMENSIONAL MODEL FOR BLOOD FLOWS AND ITS NUMERICAL APPROXIMATION

We propose a new section-averaged one-dimensional model for blood flows in deformable arteries. The model is derived from the three-dimensional Navier-Stokes equations, written in cylindrical coordinates, under the "thin-artery" assumption (similar to the "shallow-water" assumption for free surface models). The blood flow/artery interaction is taken into account through suitable boundary conditions. The obtained equations enter the scope of the non-linear convection-diffusion problems. We show that the resulting model is energetically consistent. The proposed model extends most extant models by adding more scope depending on an additional viscous term. We compare both models computationally based on an Incomplete Interior Penalty Galerkin (IIPG) method for the parabolic part, and on a Runge Kutta Discontinuous Galerkin (RKDG) method for the hyperbolic. The time discretization explicit/implicit is based on the well-known Additive Runge-Kutta (ARK) method. Moreover, through a suitable change of variables, by construction, we show that the numerical scheme is well-balanced, i.e., it preserves exactly still-steady states solutions. To end, we numerically investigate its efficiency through several test cases with a confrontation to an exact solution

Development of experimental ground truth and quantification of intracranial aneurysm pulsation in a patient

Aneurysm wall motion has been reported to be associated with rupture. However, its quantification with medical imaging is challenging and should be based on experimental ground-truth to avoid misinterpretation of results. In this work a time-resolved CT angiography (4D-CTA) acquisition protocol is proposed to detect the pulsation of intracranial aneurysms with a low radiation dose. To acquire ground-truth data, the accuracy of volume pulsation detection and quantification in a silicone phantom was assessed by applying pressure sinusoidal waves of increasing amplitudes. These experiments were carried out using a test bench that could reproduce pulsatile waveforms similar to those inside the internal carotid arteries of human subjects. 4D-CTA acquisition parameters (mAs, kVp) were then selected to achieve reliable pulsation detection and quantification with the lowest radiation dose achievable. The resulting acquisition protocol was then used to image an anterior communicating artery aneurysm in a human subject. Data reveals that in a simplified in vitro setting 4D-CTA allows for an effective and reproducible method to detect and quantify aneurysm volume pulsation with an inferior limit as low as 3 mm3 and a background noise of 0.5–1 mm3. Aneurysm pulsation can be detected in vivo with a radiation dose approximating 1 mSv.SCOPUS: ar.jinfo:eu-repo/semantics/publishe

Association of intravenous thrombolysis and pre-interventional reperfusion: a post hoc analysis of the SWIFT DIRECT trial

Stroke; Thrombectomy; ThrombolysisIctus; Trombectomia; TrombòlisiIctus; Trombectomía; TrombólisisBackground A potential benefit of intravenous thrombolysis (IVT) before mechanical thrombectomy (MT) is pre-interventional reperfusion. Currently, there are few data on the occurrence of pre-interventional reperfusion in patients randomized to IVT or no IVT before MT. Methods SWIFT DIRECT (Solitaire With the Intention For Thrombectomy Plus Intravenous t-PA vs DIRECT Solitaire Stent-retriever Thrombectomy in Acute Anterior Circulation Stroke) was a randomized controlled trial including acute ischemic stroke IVT eligible patients being directly admitted to a comprehensive stroke center, with allocation to IVT with MT versus MT alone. The primary endpoint of this analysis was the occurrence of pre-interventional reperfusion, defined as a pre-interventional expanded Thrombolysis in Cerebral Infarction score of ≥2a. The effect of IVT and potential treatment effect heterogeneity were analyzed using logistic regression analyses. Results Of 396 patients, pre-interventional reperfusion occurred in 20 (10.0%) patients randomized to IVT with MT, and in 7 (3.6%) patients randomized to MT alone. Receiving IVT favored the occurrence of pre-interventional reperfusion (adjusted OR 2.91, 95% CI 1.23 to 6.87). There was no IVT treatment effect heterogeneity on the occurrence of pre-interventional reperfusion with different strata of Randomization-to-Groin-Puncture time (p for interaction=0.33), although the effect tended to be stronger in patients with a Randomization-to-Groin-Puncture time >28 min (adjusted OR 4.65, 95% CI 1.16 to 18.68). There were no significant differences in rates of functional outcomes between patients with and without pre-interventional reperfusion. Conclusion Even for patients with proximal large vessel occlusions and direct access to MT, IVT resulted in an absolute increase of 6% in rates of pre-interventional reperfusion. The influence of time strata on the occurrence of pre-interventional reperfusion should be studied further in an individual patient data meta-analysis of comparable trials. Trial registration number clinicaltrials.gov NCT03192332

The pCONus device for the endovascular treatment of wide neck bifurcation aneurysms

Background and purpose The pCONus is a new stent featuring a distal end that opens like a blossoming flower with four petals. The device is implanted in the aneurysm sac at the level of the neck. We report our initial experience in a series of patients treated with this device. Methods This retrospective study was approved by the authors' ethics committees. 18 patients with 19 unruptured wide neck bifurcation intracranial aneurysms (IA) were treated by pCONus placement and coiling. Technical issues, immediate post treatment angiographic findings, and clinical and imaging follow-up were assessed. Results Embolization was successful in all patients. There were 11 women and 7 men with a mean age of 60 years. Median aneurysm size was 9 mm (range 5.5-25 mm). The device was precisely placed and detached in all cases, allowing for subsequent coiling. Two patients experienced a symptomatic complication, one of which, a thromboembolism, was related to the use of the pCONus. This patient had a slight hand paresis. 16 patients had a normal neurological examination at discharge. Immediate anatomical results were 13 complete occlusions, 2 neck remnants, and 4 incomplete occlusions. Imaging follow-up was obtained in 12 patients (mean 9.5 months, range 2-24 months) and showed 9 stable occlusions and 3 recanalizations, of which 2 were retreated. Conclusions In this initial series of patients, endovascular treatment of wide neck bifurcation IAs with the pCONus was feasible, with acceptable clinical and anatomical outcomes. Further studies are needed to evaluate the indications, safety, and efficacy of this new device.SCOPUS: ar.jinfo:eu-repo/semantics/publishe

CNN-LSTM Based Multimodal MRI and Clinical Data Fusion for Predicting Functional Outcome in Stroke Patients

Clinical outcome prediction plays an important role in stroke patient management. From a machine learning point-of-view, one of the main challenges is dealing with heterogeneous data at patient admission, i.e. the image data which are multidimensional and the clinical data which are scalars. In this paper, a multimodal convolutional neural network - long short-term memory (CNN-LSTM) based ensemble model is proposed. For each MR image module, a dedicated network provides preliminary prediction of the clinical outcome using the modified Rankin scale (mRS). The final mRS score is obtained by merging the preliminary probabilities of each module dedicated to a specific type of MR image weighted by the clinical metadata, here age or the National Institutes of Health Stroke Scale (NIHSS). The experimental results demonstrate that the proposed model surpasses the baselines and offers an original way to automatically encode the spatio-temporal context of MR images in a deep learning architecture. The highest AUC (0.77) was achieved for the proposed model with NIHSS.Comment: 44th Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC 2022