Passively Q-switched diode-pumped Cr4+:YAG/Nd3+:GdVO4 monolithic microchip laser

the realization of high repetition rate passively Q-switched monolithic microlaser is a challenge since a decade. To achieve this goal, we report here on the first passively Q-switched diode-pumped microchip laser based on the association of a Nd:GdVO4 crystal and a Cr4+:YAG saturable absorber. The monolithic design consists of 1 mm long 1% doped Nd:GdVO4 optically contacted on a 0.4 mm long Cr4+:YAG leading to a plano-plano cavity. A repetition rate as high as 85 kHz is achieved. The average output power is approximately 400 mW for 2.2 W of absorbed pump power and the pulse length is 1.1 ns

Waveguide grating for microchip-laser polarization control

International audienceA slab waveguide grating submirror monolithically associated with a standard multilayer submirror represents a laser output coupler which polarizes the emission of a passively Q-switched Nd:YAG microchip laser over its full emission bandwidth by intra-mirror destructive interference for the undesired polarization. A polarization extinction ratio of more than 25 dB is obtained up to 6.1µJ pulse energy. Linearly polarized emission shows no loss penalty

Microchip-laser polarization control by destructive-interference resonant-grating mirror

International audienceAn output coupler comprising a resonant grating submirror monolithically associated with a standard multilayer submirror polarizes the emission of a Nd:YAG microchip laser linearly over its full emission bandwidth by intra-mirror destructive interference for the undesired polarization. A polarization extinction ratio of more than 25 dB is obtained up to 6.1µJ pulse energy. This passively Q-switched laser performance is almost identical to that of a gratingless non-polarized microchip laser. The design and fabrication of the resonant grating mirror are described

Long-term effects of citric acid-based bicarbonate haemodialysis on patient outcomes: a survival propensity score–matched study in western France

International audienceBackground: Citric acid–based bicarbonate haemodialysis (CIT-HD) has gained more clinical acceptance over the last few years in France and is a substitute for other acidifiers [e.g. acetic acid (CH3COOH) and hydrochloric acid (HCl)]. This trend was justified by several clinical benefits compared with CH3COOH as well as the desire to avoid the consequences of the corrosive action of HCl, but a nationwide clinical report raised concerns about the long-term safety of CIT-HD. The aim of this study was to assess the long-term effects of CIT-HD exposure on patient outcomes in western France.Methods: This is a population-based retrospective multicentre observational study performed in 1132 incident end-stage kidney disease patients in five sanitary territories in western France who started their renal replacement therapy after 1 January 2008 and followed up through 15 October 2018. Relevant data, collected prospectively with the same medical software, were anonymously aggregated for the purposes of the study. The primary goal of this study was to investigate the effects of citrate exposure on all-cause mortality. To provide a control group to CIT-HD one, propensity score matching (PSM) at 2:1 was performed in two steps: the first analysis was intended to be exploratory, comparing patients who received citrate ≤80% of the time (CIT-HD ≤80) versus those who received citrate >80% of the time (CIT-HD >80), while the second analysis was intended to be explanatory in comparing patients with 0% (CIT-HD0) versus 100% citrate time exposure (CIT-HD100).Results: After PSM, in the exploratory part of the analysis, 432 CIT-HD ≤80 patients were compared with 216 CIT-HD >80 patients and no difference was found for all-cause mortality using the Kaplan–Meier model (log-rank 0.97), univariate Cox regression analysis {hazard ratio [HR] 1.01 [95% confidence interval (CI) 0.71–1.40]} and multivariate Cox regression analysis [HR 1.11 (95% CI 0.76–1.61)] when adjusted for nine variables with clinical pertinence and high statistical relevance in the univariate analysis. In the explanatory part of the analysis, 316 CIT-HD0 patients were then compared with 158 CIT-HD100 patients and no difference was found using the Kaplan–Meier model (log-rank 0.06), univariate Cox regression analysis [HR 0.69 (95% CI 0.47–1.03)] and multivariate Cox regression analysis [HR 0.87 (95% CI 0.57–1.33)] when adjusted for seven variables with clinical pertinence and high statistical relevance in the univariate analysis.Conclusions: Findings of this study support the notion that CIT-HD exposure ≤6 years has no significant effect on all-cause mortality in HD patients. This finding remains true for patients receiving high-volume online haemodiafiltration, a modality most frequently prescribed in this cohor

Prevalence of atheromatous and non-atheromatous cardiovascular disease by age in chronic kidney disease

Background:Although chronic kidney disease (CKD) and age are major risk factors for cardiovascular disease (CVD), little is known about the relative proportions of atheromatous and non-atheromatous CVD by age in CKD patients.Methods:We used baseline data from the French Chronic Kidney Disease-Renal Epidemiology and Information Network (CKD-REIN) cohort of 3033 patients (65% men) with CKD Stages 3-4 to study crude and adjusted associations between age, the estimated glomerular filtration rate (eGFR), atheromatous CVD (coronary artery disease, peripheral artery disease and stroke) and non-atheromatous CVD (heart failure, cardiac arrhythmia and valvular heart disease).Results:Mean age was 66.8 and mean Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) eGFR was 32.9 mL/min/1.73 m2. In the <65, (65-74), (75-84) and ≥85 year age groups, the prevalence was, respectively, 18.7, 35.5, 42.9 and 37.8% for atheromatous CVD, and 14.9, 28.4, 38.1 and 56.4% for non-atheromatous CVD. After adjusting for albuminuria, sex and CVD risk factors, the odds ratio (OR) [95% confidence interval (CI)] for (65-74), (75-84) and ≥85 age groups (compared with the <65 group) was, respectively, 1.99 (1.61-2.46), 2.89 (2.30-3.62), 2.72 (1.77-4.18) for atheromatous CVD and 2.07 (1.66-2.58), 3.15 (2.50-3.97), 7.04 (4.67-10.61) for non-atheromatous CVD. Compared with patients with an eGFR ≥30 mL/min/1.73 m2, those with an eGFR <30 mL/min/1.73 m2 had a higher OR for atheromatous CVD [1.21 (1.01-1.44)] and non-atheromatous CVD [1.16 (0.97-1.38)].Conclusions:In this large cohort of CKD patients, both atheromatous and non-atheromatous CVD were highly prevalent and more frequent in older patients. In a given age group, the prevalence of atheromatous and non-atheromatous CVD was similar (except for a greater prevalence of non-atheromatous CVD after 85)

J Am Med Dir Assoc

Objectives Renin-angiotensin system inhibitors (RASi) are recommended for slowing chronic kidney disease (CKD) progression to kidney failure. Their effectiveness and tolerance as patients age remain uncertain because older patients have often been excluded from clinical trials. Design CKD-REIN cohort study. Setting and Participants We studied 2762 patients with CKD stages 3 and 4 and a clinical indication for RASi enrolled between 2013 and 2016 in 40 nephrology clinics nationally representative in France. Methods The primary outcome was the occurrence of kidney failure or death. The secondary outcomes were the occurrence of cardiovascular events and hospitalizations with acute kidney injury (AKI) or hyperkalemia. A propensity score analysis was performed. We used Cox models to estimate hazard ratios (HRs) for each outcome associated with RASi prescription and tested interactions with age. Results Patients' mean age was 67 years, including 841 (30%) aged 75 years and older; 2178 (79%) were prescribed RASi's. During a median follow-up of 4.6 years, 33% of patients reached kidney failure or died. RASi prescription was associated with a lower risk of kidney failure or death (HR 0.79, 95% CI 0.66, 0.95), an association not modified by age (P for interaction = .72). It was not significantly associated with cardiovascular events. During the first 3 years of follow-up, 14% of patients were hospitalized with AKI or hyperkalemia, but risk was not higher among those prescribed RASi's (HR 0.75, 95% CI 0.55-1.02) and age did not modify its effect (P for interaction = .28). Conclusions and Implications This study shows that aging does not appear to modify either RASi's beneficial effects on major CKD outcomes or their potential adverse effects

Low incidence of SARS-CoV-2, risk factors of mortality and the course of illness in the French national cohort of dialysis patients

International audienceThe aim of this study was to estimate the incidence of COVID-19 disease in the French national population of dialysis patients, their course of illness and to identify the risk factors associated with mortality. Our study included all patients on dialysis recorded in the French REIN Registry in April 2020. Clinical characteristics at last follow-up and the evolution of COVID-19 illness severity over time were recorded for diagnosed cases (either suspicious clinical symptoms, characteristic signs on the chest scan or a positive reverse transcription polymerase chain reaction) for SARS-CoV-2. A total of 1,621 infected patients were reported on the REIN registry from March 16th, 2020 to May 4th, 2020. Of these, 344 died. The prevalence of COVID-19 patients varied from less than 1% to 10% between regions. The probability of being a case was higher in males, patients with diabetes, those in need of assistance for transfer or treated at a self-care unit. Dialysis at home was associated with a lower probability of being infected as was being a smoker, a former smoker, having an active malignancy, or peripheral vascular disease. Mortality in diagnosed cases (21%) was associated with the same causes as in the general population. Higher age, hypoalbuminemia and the presence of an ischemic heart disease were statistically independently associated with a higher risk of death. Being treated at a selfcare unit was associated with a lower risk. Thus, our study showed a relatively low frequency of COVID-19 among dialysis patients contrary to what might have been assumed