Diurnal Variations in Natriuretic Peptide Levels: Clinical Implications for the Diagnosis of Acute Heart Failure.

"Disclosures Dr Breidthardt received research grants from the Swiss National Science Foundation (PASMP3-134362), University Hospital Basel, Abbott, and Roche, as well as speaker or advisory fees from AstraZeneca, Daiichi Sankyo, Roche, and Vifor. These payments were made directly to University Hospital Basel, and no personal payments were received. Dr Kozhuharov received research grants from the Swiss National Science Foundation (P400PM-194477), Gottfried und Julia Bangerter-Rhyner-Stiftung, and the European Society of Cardiology. Dr Mueller received research grants from the Swiss National Science Foundation and the Swiss Heart Foundation, the European Union, the Cardiovascular Research Foundation Basel, the University of Basel, 8sense, Abbott, Alere, Astra Zeneca, Beckman Coulter, Biomerieux, BRAHMS, Critical Diagnostics, Nanosphere, Roche, Siemens, Singulex, and University Hospital Basel, as well as speaker or consulting honoraria from Abbott, Alere, AstraZeneca, BG Medicine, Biomerieux, Bristol Myers Squibb, Boehringer Ingelheim, BRAHMS, Cardiorentis, Daiichi Sankyo, Novartis, Roche, Sanofi, Singulex, and Siemens. Dr Meex received research funding and lecture fees from Abbott Laboratories and Roche Diagnostics. The other authors report no conflicts."

"Sources of Funding This study was supported by research grants from the European Union, the Swiss National Science Foundation, the Swiss Heart Foundation, the Cardiovascular Research Foundation Basel, the University of Basel, the University Hospital Basel, Critical Diagnostics, Abbott, Alere, BRAHMS, Roche, and Singulex. The sponsors had no role in the design and conduct of the study; collection, management, analysis, and interpretation of the data; and preparation, review, or approval of the manuscript."

"Hourly blood sampling over 1 full day (25 hours) was performed in 44 individuals divided into 2 study groups as described previously.– Briefly, the first study group consisted of 24 individuals without clinically diagnosed CKD (21% women), and the second group (30% women) consisted of 20 patients with clinically diagnosed CKD stage ≥3 (estimated glomerular filtration rate, <60 mL/min per 1.73 m2). The estimated glomerular filtration rate was calculated according to the CKD Epidemiology Collaboration formula. Exclusion criteria included current dialysis treatment, myocardial infarction in the 12 months before the study, active cardiac disease (cardiomyopathy, angina pectoris, or myocarditis), and anemia (hemoglobin, <10.5 g/dL). Subjects arrived at the laboratory by public transport or car after an overnight fast. During 25 hours, from 8.30 AM till 9.30 AM the next day, subjects were restricted to the laboratory environment, and samples were collected every hour from an antecubital venous catheter. Extension lines for blood sampling were used to prevent disturbance of participants’ sleep during the night. Meals were consumed at 8:30 AM, 12:30 PM, and 6:00 PM (breakfast, lunch, and dinner, respectively). Subjects went to bed at 11:30 PM, and lights were off between 11:35 PM and 7:00 AM. Participants were asked to refrain from exhaustive physical activities and exercise training, 2 days before the test day. Hemoglobin and hematocrit values were used to quantify possible plasma volume changes due to changes in hydration status or posture during the diurnal variation study. The serial sampling study was approved by the Institutional Review Board and Ethics Committee of the Maastricht University Medical Center and registered at https://www.clinicaltrials.gov (NCT02091427 and NCT02210897). All participants provided written informed consent. This analysis includes 21 and 19 patients with and without CKD, respectively, after exclusion of 4 individuals due to the absence of both BNP and NT-proBNP measurements. Registration:: URL: https://www.clinicaltrials.gov; Unique identifiers: NCT01831115, NCT02091427, and NCT02210897."