Rationale and design of the ADVOR (Acetazolamide in Decompensated Heart Failure with Volume Overload) trial.

Aims: Decisive evidence on the optimal diuretic agent, dosing schedule, and administration route is lacking in acute heart failure (AHF) with congestion. The Acetazolamide in Decompensated heart failure with Volume OveRload (ADVOR) trial is designed to test the hypothesis that the carbonic anhydrase inhibitor acetazolamide, a potent inhibitor of proximal tubular sodium reabsorption, improves decongestion when combined with loop diuretic therapy in AHF, potentially leading to better clinical outcomes.

Methods: The ADVOR trial is set up as a multicentre, randomized, double-blind, placebo-controlled study, aiming to recruit 519 patients with AHF and clinically evident volume overload. All study participants receive high-dose intravenous loop diuretics as background therapy and are randomized towards intravenous acetazolamide at a dose of 500 mg once daily vs. placebo, stratified according to including study centre and ejection fraction (< 40% vs. ≥ 40%). The primary endpoint is successful decongestion with no more than trace oedema assessed on the third morning after hospital admission, with good diuretic efficacy defined as a urine output > 3.5 L during the first 30-48 h of decongestive treatment. Secondary endpoints include all-cause mortality or heart failure readmission after 3 months, length of hospital stay for the index admission, and longitudinal changes in the EuroQol-5 dimensions questionnaire.

Conclusion: ADVOR will investigate if acetazolamide combined with loop diuretic therapy improves decongestion in AHF with volume overload.