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Clamart, France

Jamieson W.R.E.,University of British Columbia | Forgie W.R.,Dalhousie University | Hayden R.I.,University of British Columbia | Langlois Y.,McGill University | And 4 more authors.
Thoracic and Cardiovascular Surgeon | Year: 2010

Background: Documentation of the hemodynamics of the Mitroflow aortic pericardial bioprosthesis has been incomplete. The aim of the study was to provide reference effective orifice areas for the implant calculation of effective orifice area indexes to avoid prosthesis-patient mismatch. Methods: Echocardiograms were evaluated in 55 patients (39 females, 16 males), mean age 77.0±6.9 years (range 5190 years). The mean time of the studies was 11.0 months. The prosthesis sizes and numbers evaluated were 19mm (n=13), 21mm (n=19), 23mm (n=13) and 25mm (n=10). Results: Peak aortic velocities averaged from 2.2 to 2.7m/sec, mean gradients from 10.6 to 15.1mmHg, peak gradients from 20.7 to 29.7mmHg, and effective orifice area (EOA) from 1.4 to 1.8cm 2. When accounting for the subaortic velocity, mean gradients averaged from 7.5 to 10.0mmHg, and peak gradients averaged 15.1 to 23.5mmHg. The effective orifice area indexes ranged from 0.8 to 1.0cm2/m 2. The mean postoperative left ventricular mass index was 101.6gm/m2. Conclusions: The in vivo effective orifice areas by valve size of the Mitroflow aortic pericardial bioprosthesis provide the opportunity of avoiding obstructive characteristics for all valve sizes, including optimizing the management of the small aortic annulus. © Georg Thieme Verlag KG Stuttgart. Source


Duchateau N.,University of Barcelona | Duchateau N.,Institute dInvestigacions Biomediques August Pi i Sunyer | Duchateau N.,University Pompeu Fabra | Sitges M.,University of Barcelona | And 23 more authors.
International Journal of Cardiovascular Imaging | Year: 2014

In cardiac resynchronization therapy (CRT), specific changes in motion/deformation happen with left-bundle- branch-block (LBBB) and following treatment. However, they remain sub-optimally studied. We propose a two-fold improvement of their characterization. This includes controlling them through an experimental model and using more suitable quantification techniques. We used a swine model of acute LBBB and CRT with/without chronic infarct (pure-LBBB: N = 11; LBBB + left-anterior- descending infarct: N = 11). Myocardial displacement, velocity and strain were extracted from short-axis echocardiographic sequences using 2D speckle-tracking. The data was transformed to a single spatiotemporal system of coordinates to perform subject comparisons and quantify pattern changes at similar locations and instants. Pure-LBBB animals showed a specific intra-ventricular dyssynchrony pattern with LBBB (11/11 animals), and the recovery towards a normal pattern with CRT (10/11 animals). Pattern variability was low within the pure-LBBB population, as quantified by our method. This was not correctly assessed by more conventional measurements. Infarct presence affected the pattern distribution and CRT efficiency (improvements in 6/11 animals). Pattern changes correlated with global cardiac function (global circumferential strain) changes in all the animals (corrected: P LBBBvsBaseline < 0.001, PCRTvsBaseline = NS; non-corrected: PLBBBvsBaseline = NS, PCRTvsBaseline = 0.028). Our LBBB/CRT experimental model allowed controlling specific factors responsible for changes in mechanical dyssynchrony and therapy. We illustrated the importance of our quantification method to study these changes and their variability. Our findings confirm the importance of myocardial viability and of specific LBBB-related mechanical dyssynchrony patterns. © Springer Science+Business Media 2014. Source


Rigol M.,University of Barcelona | Solanes N.,University of Barcelona | Fernandez-Armenta J.,University of Barcelona | Silva E.,University of Barcelona | And 9 more authors.
Journal of Cardiovascular Translational Research | Year: 2013

Animal models that mimic human electrical and mechanical dyssynchrony often associated with chronic heart failure would provide an essential tool to investigate factors influencing response to cardiac resynchronization therapy. A standardized closed-chest porcine model of left bundle branch block (LBBB) was developed using 16 pigs. Radiofrequency applications were performed to induce LBBB, which was confirmed by QRS widening, a surface electrocardiogram pattern concordant with LBBB, and a prolonged activation time from endocardial. Echocardiography confirmed abnormal motion of the septum, which was not present at the baseline echocardiogram. High susceptibility of pigs to ventricular fibrillation during the endocardial ablation was overcome by applying high-rate pacing during radiofrequency applications. This is the first study to devise a closed-chest porcine model of LBBB that closely reproduces abnormalities found in patients with electrical and mechanical cardiac dyssynchrony, and provides a useful tool to investigate the basic mechanisms underlying cardiac resynchronization therapy benefits in heart failure. © 2013 Springer Science+Business Media New York. Source


Bottausci F.,CEA Grenoble | Baleras F.,CEA Grenoble | Pudda C.,CEA Grenoble | Cochet M.,CEA Grenoble | And 10 more authors.
International IEEE/EMBS Conference on Neural Engineering, NER | Year: 2015

This paper describes the fabrication and the packaging of a flexible parylene-based multi-contact electrode embedded in a silicone-based cuff. This type of electrode is well suited for peripheral nerve recording and offers improved spatial selectivity. We conducted mechanical and electrical tests for assessing the reliability by using an accelerated lifetime protocol. Test structures made with platinum sandwiched with parylene C were designed. The accelerated lifetime soaking tests in phosphate buffered saline (PBS) solution at 67°C showed a longer life time (approximatively 4.5 years) with a dehydration bake introduction in the process flow and a parylene thickness increase. A specific test bench was developed for the mechanical cycling and for evaluating the mechanical robustness of the thin film devices. © 2015 IEEE. Source


Testa A.,Expansion Centres dHemodialyse de lOuest | Dejoie T.,Nantes University Hospital Center | Lecarrer D.,Nantes University Hospital Center | Wratten M.,SORIN Group | And 2 more authors.
Blood Purification | Year: 2010

In this work we investigated the acute effects of hemodiafiltration with endogenous reinfusion (HFR therapy) on the removal of free immunoglobulin light chains (FIgLCs), which may be considered members of the family of uremic toxins. In two groups of patients - group 1 (polyclonal FIgLCs production) and group 2 (monoclonal plasma cell proliferative disorders), we analyzed the pre- and postdialysis levels of κ- and λ-chains. In group 1 we observed a significant reduction of FIgLCs (p < 0.01). A similar trend was found in patients of group 2 only for κ-chains. The FIgLCs removal ratio was significantly higher for κ- than λ-chains in the two patient groups. In vitro data showed affinity of macroporous resin to binding FIgLCs. Our results show that the HFR therapy could be effective in removing FIgLCs, particularly κ-chains in dialysis patients with polyclonal and monoclonal FIgLCs production. Copyright © 2010 S. Karger AG. Source

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