Sequential Nephron Blockade in Acute Heart Failure

Background - Volume overload is an important clinical target in acute heart failure management (AHF), typically addressed using loop diuretics. An important and challenging subset of heart failure patients exhibit fluid overload despite significant doses of loop diuretics. One approach to overcome loop diuretic resistance is the addition of a thiazide-type diuretic to produce diuretic synergy via "sequential nephron blockade". Although potentially able to induce diuresis in patients otherwise resistant to high doses of loop diuretics, this strategy has not been subjected to large-scale clinical trials to establish safety and clinical efficacy.

Methods - Our trial is a multicentric, double blind, randomized clinical study, aiming to recruit 310 patients with AHF and clinically evident volume overload. Study participants are randomized to receive a standard diuretic therapy (intravenous loop diuretics as recommended by current guidelines plus placebo) or SNB therapy (loop diuretics plus oral metolazone at the dose of 5/10 mg once daily) on top of standard medical therapy. Mineralocorticoid antagonists will be used in association with the two regimens according to blood potassium level and kidney function at the discretion of the treating physician. The primary endpoint is defined as the change in the serum creatinine level and the change in weight, considered both as a bivariate response and with their single components, between the time of randomization and 72 hours after randomization. Secondary endpoints include global well-being and dyspnoea assessed by a visual-analogue scale, changes in body weight and net fluid loss, proportion of patients free from congestion, treatment failure, changes in biomarker levels and the composite of death, rehospitalization, or an emergency room visit within 60 days, as well as the composite of total number of days hospitalized or death during the 60 days after randomization.