Clinical (pre-dialysis) evaluation of volume status In both groups (treatment and control group), a standard pre-dialysis clinical evaluation of volume status should be done, as it is recommended in good clinical practice. This evaluation should consider blood pressure and change of blood pressure over time, pedal edema, presence/absence of dyspnea, crackles on lung auscultation (see below), body weight gain inter-dialysis and body weight trajectory over time. In the active arm of the study these data should also be formally registered whenever US-B lines measurements are done. In the control group, evaluation of volume status needs to be formally registered only in coincidence of the echocardiographic studies.