A new self-expanding aortic stent valve with annular fixation: in vitro haemodynamic assessment

Objective: Balloon-expandable stent valves require flow reduction during implantation (rapid pacing). The present study was designed to compare a self-expanding stent valve with annular fixation versus a balloon-expandable stent valve. Methods: Implantation of a new self-expanding stent valve with annular fixation (Symetis®, Lausanne, Switzerland) was assessed versus balloon-expandable stent valve, in a modified Dynatek Dalta® pulse duplicator (sealed port access to the ventricle for transapical route simulation), interfaced with a computer for digital readout, carrying a 25 mm porcine aortic valve. The cardiovascular simulator was programmed to mimic an elderly woman with aortic stenosis: 120/85 mmHg aortic pressure, 60 strokes/min (66.5 ml), 35% systole (2.8 l/min). Results: A total of 450 cardiac cycles was analysed. Stepwise expansion of the self-expanding stent valve with annular fixation (balloon-expandable stent valve) resulted in systolic ventricular increase from 120 to 121 mmHg (126 to 830 ± 76 mmHg)*, and left ventricular outflow obstruction with mean transvalvular gradient of 11 ± 1.5 mmHg (366 ± 202 mmHg)*, systolic aortic pressure dropped distal to the valve from 121 to 64.5 ± 2 mmHg (123 to 55 ± 30 mmHg) N.S., and output collapsed to 1.9 ± 0.06 l/min (0.71 ± 0.37 l/min* (before complete obstruction)). No valve migration occurred in either group. (* = p < 0.05). Conclusions: Implantation of this new self-expanding stent valve with annular fixation has little impact on haemodynamics and has the potential for working heart implantation in vivo. Flow reduction (rapid pacing) is not necessar

Congenital native interruption of aortic arch in an adult: Extra-anatomic approach by right-side thoracotomy

We outline the case of an 18-year-old male patient with a congenital nonoperated interruption of the aortic arch. A right thoracotomy without cardiopulmonary bypass facilitated repair through an extra-anatomic bypass between the ascending and the supradiaphragmatic descending aorta. Results for the immediate and 2-year radiologic and clinical check-up were satisfactory. The most common complications in anatomic correction are stroke under selective cerebral perfusion, risk of paraplegia, and hemorrhage. We present a new technique for repair of interruption of the aortic arch in adults that avoids the need for extended dissection of the aorta and a partial occlusion clamp during anastomosis and allows for cerebral and medullar perfusion

Echocardiographie de l'insuffisance mitrale ischémique (approche tridimensionnelle exhaustive)

LYON1-BU Santé (693882101) / SudocSudocFranceF

Valve replacement in children: A challenge for a whole life

International audienceValvular pathology in infants and children poses numerous challenges to the paediatric cardiac surgeon. Without question, valvular repair is the goal of intervention because restoration of valvular anatomy and physiology using native tissue allows for growth and a potentially better long-term outcome. When reconstruction fails or is not feasible, valve replacement becomes inevitable. Which valve for which position is controversial. Homograft and bioprosthetic valves achieve superior haemodynamic results initially but at the cost of accelerated degeneration. Small patient size and the risk of thromboembolism limit the usefulness of mechanical valves, and somatic outgrowth is an universal problem with all available prostheses. The goal of this article is to address valve replacement options for all four valve positions within the paediatric population. We review current literature and our practice to support our preferences. To summarize, a multitude of opinions and surgical experiences exist. Today, the valve choices that seem without controversy are bioprosthetic replacement of the tricuspid valve and Ross or Ross-Konno procedures when necessary for the aortic valve. On the other hand, bioprostheses may be implanted when annular pulmonary diameter is adequate; if not or in case of right ventricular outflow tract discontinuity, it is better to use a pulmonary homograft with the Ross procedure. Otherwise, a valved conduit. Mitral valve replacement remains the most problematic; the mechanical prosthesis must be placed in the annular position, avoiding oversizing. Future advances with tissue-engineered heart valves for all positions and new anticoagulants may change the landscape for valve replacement in the paediatric population. (C) 2012 Elsevier Masson SAS. All rights reserved

Sedation versus General Anesthesia for Cardiac Catheterization in Infants: A Retrospective, Monocentric, Cohort Evaluation

Background: Children with congenital heart disease require repeated catheterization. Anesthetic management influences the procedure and may influence outcome; however, data and recommendations are lacking for infants. We studied the influence of sedation versus general anesthesia (GA) on adverse events during catheterization for children p = 0.01) after GA or sedation, respectively. HSAE occurred in 75 (20%) versus 40 (9%) (p p = 0.05), smaller weights (p p = 0.02), two-ventricle physiology (OR 7.3 [2.7–20.2], p p p p = 0.02) and procedure-type risk category 4 (OR 28.9 [1.8–455.1], p = 0.02). Sedation did not increase the events rate and decreased the requirement for hemodynamic support (OR 5.2 [2.2–12.0], p < 0.01). Conclusion: Sedation versus GA for cardiac catheterization in children <2 years old is safe and effective with regard to HSAE. Sedation also decreases the requirement for hemodynamic support. Paradoxical effects (older age and two-ventricle physiology) on risk have been found for this specific age cluster

Optical properties of Ce-doped SiO2 films: From isolated Ce3+ ions to formation of cerium silicate

Équipe 104 : NanomatériauxInternational audienceThe optical properties of Ce-doped SiO2 thin films were investigated by photoluminescence spectroscopy. Strong blue luminescence is obtained at room temperature from as-deposited films. The dependence of the luminescence on both Ce content and annealing temperature is then systematically studied. The luminescence is found to shift to higher wavelength as the annealing temperature increases. Moreover, the integrated luminescence intensity first increases for annealing temperatures between 500 degrees C and 900 degrees C as a result of the activation of Ce3+ ions and eventually decreases for higher temperatures which is interpreted by the formation of cerium clusters. At 1100 degrees C, the formation of a cerium silicate phase is observed by infrared absorption spectroscopy. X-ray diffraction measurements confirm the formation of an orthorhombic Ce6Si4(SiO4)(2)O-13 compound

Infrared photoluminescence from GeSi nanocrystals embedded in a germanium-silicate matrix.

Équipe 104 : NanomatériauxInternational audienceWe investigate the structural and optical properties of GeO/SiO multilayers obtained by evaporation of GeO and SiO powders under ultrahigh vacuum conditions on Si(001) substrates. Both Raman and infrared absorption spectroscopy measurements indicate the formation of GeSi nanocrystals after postgrowth annealing at 800°C. High-resolution transmission electron microscopy characterizations show that the average size of the nanocrystals is about 5 nm. For samples containing GeSi nanocrystals, photoluminescence is observed at 14 K in the spectral range 1500-1600 nm. The temperature dependence of the photoluminescence is studied

Correlation between the nanoscale structure and the optical properties of Ce-doped SiO 1.5 thin films

International audienceCerium doped SiO x (0 ox o 2) thin films have emerged as promising materials for future Si-based blue light emitting devices. The optical properties of these films are strongly dependent on the nanoscale structure such as the spatial distribution of the Ce atoms. These issues have remained difficult to observe in practice by conventional techniques. In this work, we propose to use atom probe tomography which has emerged as a unique technique that is able to provide information about the chemical composition of the films together with a 3D map indicating the position of each atom from a specimen. Ce-doped SiO 1.5 thin films fabricated by evaporation were investigated. The effect of Ce-content has been systematically studied in order to correlate the structure at the nanoscale with the optical properties measured by photoluminescence spectroscopy

Atomic scale investigation of Si and Ce-rich nanoclusters in Ce-doped SiO1.5 thin films

International audienceThe optical properties and the nanoscale structure of Ce‐doped SiO1.5 thin films elaborated by evaporation were investigated by photoluminescence and atom probe tomography. Strong Ce‐related blue luminescence is observed on the 1100 °C annealed sample. Atom probe tomography experiments give evidence of the formation of a cerium silicate having a stoichiometry compatible with Ce2Si2O7. Moreover, we further observe the formation of pure Si nanocrystals (Si‐ncs) which results from the phase separation of the SiO1.5 film. No optical signal from Si‐ncs was observed at least for the 3% Ce‐doped SiO1.5 film considered in this study. We analyze the size distribution of both Si‐ncs and Ce2Si2O7 particles. Finally, the Si and Ce diffusion coefficients were estimated based on atom probe tomography characterization

Correlation between the nanoscale structure and the optical properties of Ce-doped SiO 1.5 thin films

International audienceCerium doped SiO x (0 ox o 2) thin films have emerged as promising materials for future Si-based blue light emitting devices. The optical properties of these films are strongly dependent on the nanoscale structure such as the spatial distribution of the Ce atoms. These issues have remained difficult to observe in practice by conventional techniques. In this work, we propose to use atom probe tomography which has emerged as a unique technique that is able to provide information about the chemical composition of the films together with a 3D map indicating the position of each atom from a specimen. Ce-doped SiO 1.5 thin films fabricated by evaporation were investigated. The effect of Ce-content has been systematically studied in order to correlate the structure at the nanoscale with the optical properties measured by photoluminescence spectroscopy