Benefits of peritoneal ultrafiltration in HFpEF and HFrEF patients.

BACKGROUND: Peritoneal ultrafiltration (pUF) in refractory heart failure (HF) reduces the incidence of decompensation episodes, which is of particular significance as each episode incrementally adds to mortality. Nevertheless, there are insufficient data about which patient cohort benefits the most. The objective of this study was to compare pUF in HFrEF and HFpEF, focusing on functional status, hospitalizations, surrogate endpoints and mortality. METHODS: This study involves 143 patients, who could be classified as either HFpEF (n = 37, 25.9%) or HFrEF (n = 106, 74.1%) and who received pUF due to refractory HF. RESULTS: Baseline eGFR was similar in HFrEF (23.1 ± 10.6 mg/dl) and HFpEF (27.8 ± 13.2 mg/dl). Significant improvements in NYHA class were found in HFpEF (3.19 ± 0.61 to 2.72 ± 0.58, P <  0.001) and HFrEF (3.45 ± 0.52 to 2.71 ± 0.72, P <  0.001). CRP decreased in HFrEF (19.4 ± 17.6 mg/l to 13.7 ± 21.4 mg/l, P = 0.018) and HFpEF (33.7 ± 52.6 mg/l to 17.1 ± 26.3 mg/l, P = 0.004). Body weight was significantly reduced in HFrEF (81.1 ± 14.6 kg to 77.2 ± 15.6 kg, P = 0.003) and HFpEF (86.9 ± 15.8 kg to 83.1 ± 15.9 kg, P = 0.005). LVEF improved only in HFrEF (25.9 ± 6.82% to 30.4 ± 12.2%, P = 0.046). BCR decreased significantly in HFrEF and HFpEF (55.7 ± 21.9 to 34.3 ± 17.9 P > 0.001 and 50.5 ± 68.9 to 37.6 ± 21.9, P = 0.006). Number of hospitalization episodes as well as number of hospitalization days decreased significantly only in HFpEF (total number 2.88 ± 1.62 to 1.25 ± 1.45, P <  0.001, days 40.4 ± 31.7 to 18.3 ± 22.5 days, P = 0.005). CONCLUSIONS: pUF offers various benefits in HFpEF and HFrEF, but there are also substantial differences. In particular, hospitalization rates were found to be significantly reduced in HFpEF patients, indicating a greater medical and economical advantage. However, LVEF was only found to be improved in HFrEF patients. While pUF can now be regarded as an option to supplement classical HF therapy, further studies are desirable to obtain specifications about pUF in HFpEF, HFmEF and HFrEF patients.

Special Issue on Remote Sensing of Ocean Color: Theory and Applications.

The editorial team are delighted to present this Special Issue of Sensors focused on Remote Sensing of Ocean Color: Theory and Applications. We believe that this is a timely opportunity to showcase current developments across a broad range of topics in ocean color remote sensing (OCRS). Although the field is well-established, in this Special Issue we are able to highlight advances in the applications of the technology, our understanding of the underpinning science, and its relevance in the context of monitoring climate change and engaging public participation.

An Ocean-Colour Time Series for Use in Climate Studies: The Experience of the Ocean-Colour Climate Change Initiative (OC-CCI).

Ocean colour is recognised as an Essential Climate Variable (ECV) by the Global Climate Observing System (GCOS); and spectrally-resolved water-leaving radiances (or remote-sensing reflectances) in the visible domain, and chlorophyll-a concentration are identified as required ECV products. Time series of the products at the global scale and at high spatial resolution, derived from ocean-colour data, are key to studying the dynamics of phytoplankton at seasonal and inter-annual scales; their role in marine biogeochemistry; the global carbon cycle; the modulation of how phytoplankton distribute solar-induced heat in the upper layers of the ocean; and the response of the marine ecosystem to climate variability and change. However, generating a long time series of these products from ocean-colour data is not a trivial task: algorithms that are best suited for climate studies have to be selected from a number that are available for atmospheric correction of the satellite signal and for retrieval of chlorophyll-a concentration; since satellites have a finite life span, data from multiple sensors have to be merged to create a single time series, and any uncorrected inter-sensor biases could introduce artefacts in the series, e.g., different sensors monitor radiances at different wavebands such that producing a consistent time series of reflectances is not straightforward. Another requirement is that the products have to be validated against in situ observations. Furthermore, the uncertainties in the products have to be quantified, ideally on a pixel-by-pixel basis, to facilitate applications and interpretations that are consistent with the quality of the data. This paper outlines an approach that was adopted for generating an ocean-colour time series for climate studies, using data from the MERIS (MEdium spectral Resolution Imaging Spectrometer) sensor of the European Space Agency; the SeaWiFS (Sea-viewing Wide-Field-of-view Sensor) and MODIS-Aqua (Moderate-resolution Imaging Spectroradiometer-Aqua) sensors from the National Aeronautics and Space Administration (USA); and VIIRS (Visible and Infrared Imaging Radiometer Suite) from the National Oceanic and Atmospheric Administration (USA). The time series now covers the period from late 1997 to end of 2018. To ensure that the products meet, as well as possible, the requirements of the user community, marine-ecosystem modellers, and remote-sensing scientists were consulted at the outset on their immediate and longer-term requirements as well as on their expectations of ocean-colour data for use in climate research. Taking the user requirements into account, a series of objective criteria were established, against which available algorithms for processing ocean-colour data were evaluated and ranked. The algorithms that performed best with respect to the climate user requirements were selected to process data from the satellite sensors. Remote-sensing reflectance data from MODIS-Aqua, MERIS, and VIIRS were band-shifted to match the wavebands of SeaWiFS. Overlapping data were used to correct for mean biases between sensors at every pixel. The remote-sensing reflectance data derived from the sensors were merged, and the selected in-water algorithm was applied to the merged data to generate maps of chlorophyll concentration, inherent optical properties at SeaWiFS wavelengths, and the diffuse attenuation coefficient at 490 nm. The merged products were validated against in situ observations. The uncertainties established on the basis of comparisons with in situ data were combined with an optical classification of the remote-sensing reflectance data using a fuzzy-logic approach, and were used to generate uncertainties (root mean square difference and bias) for each product at each pixel.

Peritoneal dialysis as therapeutic option in heart failure patients.

AIMS: Each episode of acute decompensated heart failure (HF) incrementally adds to mortality. Peritoneal dialysis (PD) offers an alternative therapeutic option in refractory HF and reduces the incidence of decompensation episodes. The objective of this study was to determine the efficacy of PD, in terms of functional status, surrogate endpoints, rate of hospitalizations, and mortality. METHODS AND RESULTS: This study is based on the registry of the German Society of Nephrology, involving 159 patients receiving PD treatment due to refractory HF between January 2010 and December 2014. Body weight was reduced by PD (82.2 ± 14.9 to 78.4 ± 14.8 kg, P < 0.001), and significant improvements in New York Heart Association functional class (3.38 ± 0.55 to 2.85 ± 0.49, P < 0.001) were found already after 3 months. Left ventricular ejection fraction did not change (31.5 ± 13.8 to 34.0 ± 15.7%, P = 0.175). C-reactive protein improved with PD treatment (33.7 ± 52.6 to 17.1 ± 26.3 mg/L, P = 0.004). Blood urea nitrogen/creatinine ratio decreased significantly (148.7 ± 68.3 to 106.7 ± 44.8 mg/dL, P < 0.001). Hospitalization rates decreased significantly (total number 2.86 ± 1.88 to 1.90 ± 1.78, P = 0.001, and 39.2 ± 30.7 to 27.1 ± 25.2 days, P = 0.004). One year mortality was 39.6% in end-stage HF patients treated with PD. CONCLUSIONS: Peritoneal dialysis offers an additional therapeutic option in end-stage HF and is associated with improved New York Heart Association classification and reduced hospitalization. Although PD treatment was associated with various benefits, further studies are necessary to identify which patients benefit the most from PD.

Satellite Ocean Colour: Current Status and Future Perspective.

Spectrally resolved water-leaving radiances (ocean colour) and inferred chlorophyll concentration are key to studying phytoplankton dynamics at seasonal and interannual scales, for a better understanding of the role of phytoplankton in marine biogeochemistry; the global carbon cycle; and the response of marine ecosystems to climate variability, change and feedback processes. Ocean colour data also have a critical role in operational observation systems monitoring coastal eutrophication, harmful algal blooms, and sediment plumes. The contiguous ocean-colour record reached 21 years in 2018; however, it is comprised of a number of one-off missions such that creating a consistent time-series of ocean-colour data requires merging of the individual sensors (including MERIS, Aqua-MODIS, SeaWiFS, VIIRS, and OLCI) with differing sensor characteristics, without introducing artefacts. By contrast, the next decade will see consistent observations from operational ocean colour series with sensors of similar design and with a replacement strategy. Also, by 2029 the record will start to be of sufficient duration to discriminate climate change impacts from natural variability, at least in some regions. This paper describes the current status and future prospects in the field of ocean colour focusing on large to medium resolution observations of oceans and coastal seas. It reviews the user requirements in terms of products and uncertainty characteristics and then describes features of current and future satellite ocean-colour sensors, both operational and innovative. The key role of in situ validation and calibration is highlighted as are ground segments that process the data received from the ocean-colour sensors and deliver analysis-ready products to end-users. Example applications of the ocean-colour data are presented, focusing on the climate data record and operational applications including water quality and assimilation into numerical models. Current capacity building and training activities pertinent to ocean colour are described and finally a summary of future perspectives is provided.