Imagerie dans le cathétérisme des cardiopathies congénitales : place de l’échocardiographie 3D transthoracique

RésuméL’échocardiographie 3D transthoracique a longtemps été freinée dans son développement en raison de conditions techniques d’acquisition compliquées et de qualité d’images médiocres. L’avènement des sondes matricielles permet au 3D en devenant temps réel d’entrer dans la pratique clinique courante. Si la voie œsophagienne a permis au 3D de trouver ses lettres de noblesses par ses descriptions anatomiques uniques des valves et des septa, l’échocardiographie transthoracique peut désormais se décliner en modes 2D, Doppler et 3D. Ses applications dans la cardiologie congénitale et pédiatrique sont multiples : description anatomique précise des défauts septaux auriculaires et ventriculaires, classification des bicuspidies aortiques et analyse du mécanisme de sténose. Ainsi, l’échocardiographie 3D permet-elle de sélectionner de façon non invasive les patients, de guider et de juger du résultat d’un cathétérisme interventionnel. L’imagerie 3D est un excellent moyen de communication entre l’imageur et le cardiologue interventionnel mais aussi de délivrer des informations claires au patient et à la famille avant et après un cathétérisme.SummaryThree-dimensional echocardiography has improved dramatically due to technical advances in probe design and computer processing. The introduction of real time 3D echocardiography has led to its use in everyday clinical practice. Congenital heart disease demands a detailed understanding of the spatial relationships of cardiac structures to plan treatment. The introduction of new transthoracic 3D probes has extended the applications to real-time guidance of catheter procedures. Prominent among the cardiac lesions which have been studied are: atrial septal defects, ventricular septal defects and stenotic bicuspid aortic valves. Its values should be decisive in many congenital cardiac lesions requiring interventional catheterisation. 3D echocardiography is an easy way to communicate to the patient and its family about the pathology

ACT variation after a weight-based heparin bolus before CPB is not predictable in infant

BackgroundIn pediatric cardiac surgery, anticoagulation protocols are derived from adult protocols. Age, Antithrombin III level, and capacity to generate thrombin are factors that affect unfractionated heparin (UFH) action in children. A starting UFH dose of 400 UI/kg is recommended to get an Activated Clotting Time (ACT) target over 400seconds. In our daily practice, we noticed a wide range of ACT increase (ΔACT) after this standardized weight based bolus of UFH.ObjectiveTo define factors affecting UFH effectiveness based on ΔACT before CPB initialization in pediatric cardiac surgery.MethodsA retrospective chart review of patient undergoing cardiac surgery requiring CPB in a single university hospital was performed. Patients receiving preoperative anticoagulation therapy or platelet aggregation inhibitors were excluded. We searched predictive factors for ΔACT. We defined 2 groups: hyperrespondents (HR; ΔACT>500) and normorespondents (NR; ΔACT<500).ResultsSeventy-nine charts were reviewed. Median [25–75] age and weight were respectively 13.8 [5–72] months and 8.7 kg [5.5–18.8]. UFH pre CPB bolus was 384 [358–410] to increase pre operative ACT from 124 [115–137] to 536 s[463–582]. HR are younger (4.9 [3.7–13] vs 24.6 [5.7–76] months, P<0.05) and have smaller weight (6,1 [4.6–7.8] vs 10 kg[5,8–19.5], P<0,05) than NR. ΔACT is correlated to UFH dose for patients>5 months (r=0.59 P=0.00001) and>5kg (r=0.54 P=0.00001) for with a predictive ΔACT of 386 s [325–443]. There is no correlation between ΔACT and UFH dose for patients<5 months and<5kg.ConclusionA dose UFH of 400 UI/kg before starting CPB in pediatrics is overestimated, especially for children<5 months and<5kg. Accurate dose for ACT target>400 s in this specific population should be calculated using other method that still needs to be developed to avoid complications associated to excessive dose of UFH

Checkpointing with Time Gaps for Unsteady Adjoint CFD

© Springer International Publishing AG 2019. Gradient-based optimisation using adjoints is an increasingly common approach for industrial flow applications. For cases where the flow is largely unsteady however, the adjoint method is still not widely used, in particular because of its prohibitive computational cost and memory footprint. Several methods have been proposed to reduce the peak memory usage, such as checkpointing schemes or checkpoint compression, at the price of increasing the computational cost even further. We investigate incomplete checkpointing as an alternative, which reduces memory usage at almost no extra computational cost, but instead offers a trade-off between memory footprint and the fidelity of the model. The method works by storing only selected physical time steps and using interpolation to reconstruct time steps that have not been stored. We show that this is enough to compute sufficiently accurate adjoint sensitivities for many relevant cases, and does not add significantly to the computational cost. The method works for general cases and does not require to identify periodic cycles in the flow

Control of flow geometry using electromagnetic body forcing

Accepted versio

Ventricular arrhythmias and sudden death in tetralogy of Fallot

Cardiolog

Percutaneous Pulmonary Valve Implantation in Small Conduits: A Multicenter Experience

BACKGROUND: Guidelines allow percutaneous pulmonary valve implantation (PPVI) in conduits above 16mm diameter. Balloon dilatation of a conduit to a diameter>110% of the original implant size is also not recommended. We analyzed patients undergoing PPVI in such conditions. METHODS AND RESULTS: Nine patients (May 2008-July 2016) from 8 institutions underwent PPVI in conduits 110%. Mean age and weight of the 14 patients was 12.1 (7.7 to 16) years and 44.9 (19 to 83) kg. Median conduit diameter at PPVI was 12 (10 to 17) mm. Median systolic right ventricular pressure was 70 (40 to 94) mmHg. Procedure was successful in all cases. A confined conduit rupture occurred in 7 patients (50%) and was treated with covered stent in 6. One patient experienced dislocation of 2 pulmonary artery stents that were parked distally. The post-implantation median systolic right ventricular pressure was 36 (28 to 51) mmHg. A fistula between right-ventricle outflow and aorta was found in one patient, secondary to undiagnosed conduit rupture. This was closed surgically. After a median follow-up of 20.16 (6.95 to 103.61) months, all the patients are asymptomatic with no significant RVOT stenosis. CONCLUSIONS: PPVI is feasible in small conduits but rate of ruptures is high. Although such ruptures remain contained and can be managed with covered stents in our experience, careful selection of patients and high level of expertise are necessary. More studies are needed to better assess the risk of PPVI in this population.info:eu-repo/semantics/publishedVersio

Variational methods

International audienceThis contribution presents derivative-based methods for local sensitivity analysis, called Variational Sensitivity Analysis (VSA). If one defines an output called the response function, its sensitivity to inputs variations around a nominal value can be studied using derivative (gradient) information. The main issue of VSA is then to provide an efficient way of computing gradients. This contribution first presents the theoretical grounds of VSA: framework and problem statement, tangent and adjoint methods. Then it covers pratical means to compute derivatives, from naive to more sophisticated approaches, discussing their various 2 merits. Finally, applications of VSA are reviewed and some examples are presented, covering various applications fields: oceanography, glaciology, meteorology

The obesity paradox in men with coronary heart disease and heart failure: the role of muscle mass and leptin.

AIMS: We have investigated the role of muscle mass, natriuretic peptides and adipokines in explaining the obesity paradox. BACKGROUND: The obesity paradox relates to the association between obesity and increased survival in patients with coronary heart disease (CHD) or heart failure (HF). METHODS: Prospective study of 4046 men aged 60-79 years followed up for a mean period of 11 years, during which 1340 deaths occurred. The men were divided according to the presence of doctor diagnosed CHD and HF: (i) no CHD or HF ii), with CHD (no HF) and (iii) with HF. RESULTS: Overweight (BMI 25-9.9 kg/m(2)) and obesity (BMI ≥ 30 kg/m(2)) were associated with lower mortality risk compared to men with normal weight (BMI 18.5-24.9 kg/m(2)) in those with CHD [hazards ratio (HR) 0.71 (0.56,0.91) and 0.77 (0.57,1.04); p=0.04 for trend] and in those with HF [HR 0.57 (0.28,1.16) and 0.41 (0.16,1.09; p=0.04 for trend). Adjustment for muscle mass and NT-proBNP attenuated the inverse association in those with CHD (no HF) [HR 0.78 (0.61,1.01) and 0.96 (0.68,1.36) p=0.60 for trend) but made minor differences to those with HF [p=0.05]. Leptin related positively to mortality in men without HF but inversely to mortality in those with HF; adjustment for leptin abolished the BMI mortality association in men with HF [HR 0.82 (0.31,2.20) and 0.99 (0.27,3.71); p=0.98 for trend]. CONCLUSION: The lower mortality risk associated with excess weight in men with CHD without HF may be due to higher muscle mass. In men with HF, leptin (possibly reflecting cachexia) explain the inverse associatio

Biases in the Explore-Exploit Tradeoff in Addictions: The Role of Avoidance of Uncertainty.

We focus on exploratory decisions across disorders of compulsivity, a potential dimensional construct for the classification of mental disorders. Behaviors associated with the pathological use of alcohol or food, in alcohol use disorders (AUD) or binge-eating disorder (BED), suggest a disturbance in explore-exploit decision-making, whereby strategic exploratory decisions in an attempt to improve long-term outcomes may diminish in favor of more repetitive or exploitatory choices. We compare exploration vs exploitation across disorders of natural (obesity with and without BED) and drug rewards (AUD). We separately acquired resting state functional MRI data using a novel multi-echo planar imaging sequence and independent components analysis from healthy individuals to assess the neural correlates underlying exploration. Participants with AUD showed reduced exploratory behavior across gain and loss environments, leading to lower-yielding exploitatory choices. Obese subjects with and without BED did not differ from healthy volunteers but when compared with each other or to AUD subjects, BED had enhanced exploratory behaviors particularly in the loss domain. All subject groups had decreased exploration or greater uncertainty avoidance to losses compared with rewards. More exploratory decisions in the context of reward were associated with frontal polar and ventral striatal connectivity. For losses, exploration was associated with frontal polar and precuneus connectivity. We further implicate the relevance and dimensionality of constructs of compulsivity across disorders of both natural and drug rewards.The study was funded by the Wellcome Trust Fellowship grant for VV (093705/Z/10/Z) and Cambridge NIHR Biomedical Research Centre. VV and NAH are Wellcome Trust (WT) intermediate Clinical Fellows. LSM is in receipt of an MRC studentship. The BCNI is supported by a WT and MRC grant. MF is funded by NIMH and NSF grants and is consultant for Hoffman LaRoche pharmaceuticals. The remaining authors declare no competing financial interests.This is the final version of the article. It first appeared from NPG via http://dx.doi.org/10.1038/npp.2015.20