Publications by authors named "Didier Locca"

In this paper, we propose a novel approach to utilize silicon nanowires as high-sensitivity pH sensors. Our approach works based on fixing the current bias of silicon nanowires Ion Sensitive Field Effect Transistors (ISFETs) and monitor the resulting drain voltage as the sensing signal. By fine tuning the injected current levels, we can optimize the sensing conditions according to different sensor requirements.

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Objectives: Percutaneous indirect annuloplasty has emerged as a treatment strategy for functional/ischemic mitral regurgitation. This study sought to evaluate the feasibility of percutaneous indirect annuloplasty technique using a new device.

Methods: The device has 3 components: the "saddle" inserted into the great cardiac vein, the "plug" positioned in the left ventricular outflow tract, and the "bridge," a transatrial suture connecting the 2 holding elements.

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Given the logistical issues surrounding intramyocardial cell delivery, we sought to address the efficacy of the simpler, more accessible intracoronary route by re-evaluating REGENERATE-DCM and REGENERATE-IHD (autologous cell therapy trials for heart failure; n = 150). A retrospective statistical analysis was performed on the trials' combined data. The following end points were evaluated: left ventricular ejection fraction (LVEF), N-terminal pro brain natriuretic peptide concentration (NT-proBNP), New York Heart Association class (NYHA) and quality of life.

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Aims: The long-term outcomes of the intracoronary delivery of autologous bone marrow-derived cells (BMCs) after acute myocardial infarction are not well established. Following the promising 1 year results of the REGENERATE-AMI trial (despite it not achieving its primary endpoint), this paper presents the analysis of the 5 year clinical outcomes of these acute myocardial infarction patients who were treated with an early intracoronary autologous BMC infusion or placebo.

Methods And Results: A 5 year follow-up of major adverse cardiac events (defined as the composite of all-cause death, recurrent myocardial infarction, and all coronary revascularization) and of rehospitalization for heart failure was completed in 85 patients (BMC n = 46 and placebo n = 39).

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Peak post-operative cardiac troponin T (cTnT) independently predicts mid- and long-term outcome of cardiac surgery patients. A few studies however have reported two peaks of cTnT over the first 48-72 h following myocardial reperfusion. The aim of the current study was to better understand underlying reasons of these different cTnT profiles and their possible relevance in terms of clinical outcome.

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Aims: The effect of combined cytokine and cell therapy in ischaemic cardiomyopathy is unknown. Meta-analyses suggest improved cardiac function with cell therapy. The optimal cell delivery route remains unclear.

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Objectives: This study explored whether cardiac magnetic resonance (CMR) could help select patients who could benefit from revascularization by identifying inducible myocardial ischemia and viability in the perfusion territory of the artery with chronic total occlusion (CTO).

Background: The benefit of revascularization using percutaneous coronary intervention (PCI) in CTO is controversial. CMR offers incomparable left ventricular (LV) systolic function assessment in addition to potent ischemic burden quantification and reliable myocardial viability analysis.

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Background: AAR measurement is useful when assessing the efficacy of reperfusion therapy and novel cardioprotective agents after myocardial infarction. Multi-slice (Typically 10-12) T2-STIR has been used widely for its measurement, typically with a short axis stack (SAX) covering the entire left ventricle, which can result in long acquisition times and multiple breath holds. This study sought to compare 3-slice T2-short-tau inversion recovery (T2- STIR) technique against conventional multi-slice T2-STIR technique for the assessment of area at risk (AAR).

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Aims: The present study aimed to document a local pattern of care in consecutive patients undergoing primary percutaneous coronary intervention for ST-elevation myocardial infarction (STEMI) in a tertiary centre in Switzerland.

Methods: A retrospective study was conducted at the University Hospital of Lausanne, Switzerland. A total of 389 consecutive patients undergoing primary percutaneous coronary intervention for STEMI between 2009 and 2010 were studied.

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Aims: Clinical trials suggest that intracoronary delivery of autologous bone marrow-derived cells (BMCs) 1-7 days post-acute myocardial infarction (AMI) may improve left ventricular (LV) function. Earlier time points have not been evaluated. We sought to determine the effect of intracoronary autologous BMC on LV function when delivered within 24 h of successful reperfusion therapy.

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Aims: The REGENERATE-DCM trial is the first phase II randomized, placebo-controlled trial aiming to assess if granulocyte colony-stimulating factor (G-CSF) administration with or without adjunctive intracoronary (IC) delivery of autologous bone marrow-derived cells (BMCs) improves global left ventricular (LV) function in patients with dilated cardiomyopathy (DCM) and significant cardiac dysfunction.

Methods And Results: Sixty patients with DCM and left ventricular ejection fraction (LVEF) at referral of ≤45%, New York Heart Association (NYHA) classification ≥2 and no secondary cause for the cardiomyopathy were randomized equally into four groups: peripheral placebo (saline), peripheral G-CSF, peripheral G-CSF and IC serum, and peripheral G-CSF and IC BMC. All patients, except the peripheral placebo group, received 5 days of G-CSF.

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During transapical transcatheter aortic valve replacement (TA-TAVR), the apical closure remains a challenge for the surgeon, having the risk for ventricular tear and massive bleeding. Apical closure devices are already under clinical evaluation, but only a few can lead to a full percutaneous TA-TAVR. We describe the successful use of a 9-mm myocardial occluder (ventricular septal defect occluder) that was used to seal the apex after a standard TA-TAVR (using the Sapien XT 23-mm transcatheter valve and the Ascendra + delivery system).

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Background: To test the hypothesis that intervals with superior beat-to-beat coronary artery repositioning precision exist in the cardiac cycle, to design a coronary MR angiography (MRA) methodology in response, and to ascertain its performance.

Methods: Coronary repositioning precision in consecutive heartbeats was measured on x-ray coronary angiograms of 17 patients and periods with the highest repositioning precision were identified. In response, the temporal order of coronary MRA pulse sequence elements required modification and the T2 -prep now follows (T2 -post) rather than precedes the imaging part of the sequence.

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Aim: This study presents an interim safety and feasibility analysis of the REGENERATE-IHD randomized controlled trial, which is examining the safety and efficacy of three different delivery routes of bone marrow-derived stem cells (BMSCs) in patients with ischemic heart failure.

Methods & Results: The first 58 patients recruited to the REGENERATE-IHD study are included in this interim analysis (pilot). Symptomatic patients with ischemic heart failure were randomized to receive subcutaneous granulocyte colony-stimulating factor or saline injections only; or subcutaneous granulocyte colony-stimulating factor injections followed by intracoronary or intramyocardial injections of BMSCs or serum (control).

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Introduction: Acute myocardial infarction (AMI) remains a major cause of mortality and morbidity worldwide despite the latest therapeutic advances designed to decrease myocardial injury. Preclinical and emerging clinical evidence show that the intracoronary injection of autologous bone marrow mononuclear cells (BMCs) following AMI leads to improvement in left ventricular ejection function (LVEF). In this clinical trial we will for the first time assess the effect of early (<24 h) infusion of autologous BMCs following AMI on cardiac function.

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Aortic stenosis mostly occurs among old-old patients. Once symptoms appear, prognosis is guarded, with 2-year mortality as high as 50%. Transcatheter Aortic Valve Implantation (TAVI) is a new therapeutic option in patients at very high surgical risk, who are mostly older persons.

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Urgent reoperative transapical aortic valve-in-valve has never been proposed as a treatment option in case of a failed transcatheter aortic valve implantation (TAVI) or in case of worsening of an existing paravalvular leak, if this complication occurs right after, or a few days after, the primary transapical aortic valve implantation. Experienced surgeons should argue that after a transapical TAVI, the apex is damaged and fragile, with a high risk of irreparable ventricular tears and life-threatening bleeding if a second transapical procedure is scheduled during the acute phase. Nevertheless, if the patient is inoperable and the vascular status, including the ascending aorta, limits alternative accesses, the urgent reoperative transapical valve-in-valve becomes an alternative.

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In some high-risk patients, standard mitral valve replacement can represent a challenging procedure, requiring a risky extensive decalcification of the annulus. In particular, high-risk redo patients and patients with a previously implanted transcatheter aortic valve, who develop calcific mitral disease, would benefit from the development of new, minimally invasive, transcatheter or hybrid techniques for mitral valve replacement. In particular, mixing transcatheter valve therapies and well-established minimally invasive techniques for mitral replacement or repair can help in decreasing the surgical risk and the technical complexity.

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Background: Cardiovascular magnetic resonance (CMR) has become an important diagnostic imaging modality in cardiovascular medicine. However, insufficient image quality may compromise its diagnostic accuracy. We aimed to describe and validate standardized criteria to evaluate a) cine steady-state free precession (SSFP), b) late gadolinium enhancement (LGE), and c) stress first-pass perfusion images.

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Objectives: Residual mitral regurgitation after valve repair worsens patients' clinical outcome. Postimplant adjustable mitral rings potentially address this issue, allowing the reshaping of the annulus on the beating heart under echocardiography control. We developed an original mitral ring allowing valve geometry remodelling after the implantation and designed an animal study to assess device effectiveness in correcting residual mitral regurgitation.

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Cell-based regenerative therapy treatment of cardiovascular diseases considered as irreversible, as acute myocardial infarction, chronic ischemic heart failure, non-ischemic dilated cardiomyopathy and refractory angina pectoris. Large randomized clinical trials with hard clinical endpoints are still necessary before considering cell-based regenerative therapy as a valuable alternative therapeutic option in cardiology.

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Objectives: This study sought to establish an accurate and reproducible T(2)-mapping cardiac magnetic resonance (CMR) methodology at 3 T and to evaluate it in healthy volunteers and patients with myocardial infarct.

Background: Myocardial edema affects the T(2) relaxation time on CMR. Therefore, T(2)-mapping has been established to characterize edema at 1.

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Acute myocarditis was until recently one of the most difficult diagnoses in cardiology. The spectrum of signs and symptoms is very wide, the usual non-invasive tests lack specificity and the myocardial biopsy is only performed in a minority of cases to confirm the diagnosis. Due to its unique ability to directly image myocardial necrosis, fibrosis and oedema, cardiac magnetic resonance (CMR) is now considered the primary tool for noninvasive assessment of patients with suspected myocarditis.

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We describe a device made of artificial muscle for the treatment of end-stage heart failure as an alternative to current heart assist devices. The key component is a matrix of nitinol wires and aramidic fibers called Biometal muscle (BM). When heated electrically, it produces a motorless, smooth, and lifelike motion.

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