TACTIC-HF: Sequential Diuretic Strategies in Ambulatory Worsening Heart Failure (TACTIC-HF)

May 11, 2026 updated by: Lucrecia Maria Burgos

TACTIC-HF: Thiazide or Acetazolamide Combination Versus Intravenous Furosemide in Ambulatory Worsening Heart Failure - a Randomized Crossover Trial

TACTIC-HF is a prospective randomized crossover trial designed to compare three ambulatory diuretic strategies in patients with worsening heart failure treated in a specialized heart failure day-hospital program.

Participants will receive sequential treatment with:

  1. intravenous furosemide alone,
  2. intravenous furosemide combined with oral acetazolamide, and
  3. intravenous furosemide combined with oral hydrochlorothiazide.

The primary objective is to compare short-term natriuretic response between strategies. Secondary objectives include assessment of urine output, congestion parameters, and renal/electrolyte safety.

Each participant will undergo repeated outpatient treatment sessions separated by washout periods, with standardized clinical and laboratory monitoring performed during each visit.

The study aims to evaluate pragmatic and clinically applicable ambulatory decongestion strategies using approved therapies commonly available in real-world practice.

Study Overview

Status

Not yet recruiting

Conditions

Intervention / Treatment

Detailed Description

Heart failure congestion remains one of the leading causes of hospitalization and recurrent healthcare utilization worldwide. Although loop diuretics represent the cornerstone of decongestive therapy, many patients develop suboptimal diuretic response or diuretic resistance during the course of chronic heart failure.

Sequential nephron blockade strategies combining loop diuretics with agents acting at different tubular sites may enhance natriuresis and improve decongestion. Recent inpatient studies have suggested potential benefits of acetazolamide- and thiazide-based strategies; however, evidence regarding ambulatory worsening heart failure management remains limited.

TACTIC-HF is a prospective, single-center, randomized, open-label crossover trial evaluating three commonly used outpatient decongestion strategies in patients with worsening heart failure treated in a dedicated heart failure day-hospital setting.

Participants will sequentially receive:

  • intravenous furosemide alone,
  • intravenous furosemide plus oral acetazolamide,
  • intravenous furosemide plus oral hydrochlorothiazide.

Treatments will be administered during structured outpatient sessions with standardized monitoring and predefined washout intervals between treatment periods.

The primary endpoint is total urinary sodium excretion during the treatment session. Secondary endpoints include urine output, congestion-related parameters, and renal/electrolyte safety outcomes.

The study is designed as a pragmatic trial using approved therapies routinely available in clinical practice, with the objective of generating physiologically oriented evidence applicable to ambulatory heart failure care.

Study Type

Interventional

Enrollment (Estimated)

60

Phase

  • Phase 4

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  • Age ≥18 years Chronic heart failure diagnosis according to current guideline definitions Ambulatory worsening heart failure requiring intravenous diuretic therapy in a specialized outpatient setting Evidence of clinical or objective congestion Chronic outpatient loop diuretic therapy Ability to comply with study procedures Written informed consent

Exclusion Criteria:

  • Hemodynamic instability or cardiogenic shock Requirement for immediate hospitalization Acute coronary syndrome, active infection, pulmonary embolism, or uncontrolled arrhythmia Severe electrolyte abnormalities Advanced renal failure requiring dialysis Pregnancy or breastfeeding Contraindication or allergy to study medications Current treatment with acetazolamide or thiazide diuretics Any condition that, in the opinion of the investigators, would make study participation unsafe or interfere with study procedures

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: Randomized
  • Interventional Model: Crossover Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Active Comparator: Intravenous Furosemide
Participants receive outpatient intravenous furosemide according to the study protocol during a structured ambulatory treatment session.
Drug: Intravenous furosemide bolus injections
Intravenous loop diuretic therapy administered during outpatient treatment sessions according to protocol-defined dosing categories.
Experimental: Intravenous Furosemide + Acetazolamide
Participants receive outpatient intravenous furosemide combined with oral acetazolamide during a structured ambulatory treatment session
Drug: Intravenous furosemide bolus injections
Intravenous loop diuretic therapy administered during outpatient treatment sessions according to protocol-defined dosing categories.
Drug: ACETAZOLAMIDE oral capsule
Oral acetazolamide administered prior to intravenous loop diuretic therapy during outpatient treatment sessions
Experimental: Intravenous Furosemide + Hydrochlorothiazide
Participants receive outpatient intravenous furosemide combined with oral hydrochlorothiazide during a structured ambulatory treatment session
Drug: Intravenous furosemide bolus injections
Intravenous loop diuretic therapy administered during outpatient treatment sessions according to protocol-defined dosing categories.
Drug: Hydrochlorothiazide (HCT)
Oral hydrochlorothiazide administered prior to intravenous loop diuretic therapy during outpatient treatment sessions.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Total Urinary Sodium Excretion at 6 Hours
Time Frame: 6 hours
Total urine volume collected during the outpatient treatment session
6 hours

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Lucrecia Maria Burgos

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Estimated)

June 15, 2026

Primary Completion (Estimated)

January 15, 2027

Study Completion (Estimated)

January 15, 2027

Study Registration Dates

First Submitted

May 11, 2026

First Submitted That Met QC Criteria

May 11, 2026

First Posted (Actual)

May 18, 2026

Study Record Updates

Last Update Posted (Actual)

May 18, 2026

Last Update Submitted That Met QC Criteria

May 11, 2026

Last Verified

May 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • TACTIC-HF
  • 2 (Other Identifier: Instituto Cardiovascular de Buenos Aires)

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

product manufactured in and exported from the U.S.

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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