Heart FailureSANDINCT06285760
Effect of Acetazolamide on Diuresis and Natriuresis in Patients With Acute Heart Failure (SANDI STUDY)
An observational study of Heart Failure and Persistent Congestion, run by Puerta de Hierro University Hospital at 1 site in Spain.
Trial summary
The goal of this observational study is to assess the natriuretic effect of intravenous acetazolamide in patients admitted with heart failure and persistent congestion despite treatment with intravenous furosemide and sodium-glucose cotransporter type 2 (iSGLT2) inhibitors. Read more about this study
- Who is it for?
- Any age
- Conditions the study is for
- Heart Failure, Persistent Congestion
- What is being tested?
- Acetazolamide 500mg
- Type of treatment
- Injection or infusion
- How many people
- 64 participants
- Where
- 1 siteSpain
- Study dates
- 1 Mar 2024to 31 Dec 2026
- Phase
- Observational
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages Any age
- All sexes
- No healthy volunteers
- Child, Adult, Older adult
Study population: Patients admitted for heart failure with persistent findings of residual congestion who meet the inclusion criteria and none of the exclusion criteria.
Who may be able to join
- Patients admitted for acute heart failure and ≥ 1 clinical sign of volume overload (edema, ascites, or pleural effusion).
- NTproBNP levels >1000 pg/mL or BNP >250 ng/mL on admission.
- Under treatment with furosemide and iSGLT2 according to European guidelines and indication of association of another diuretic due to residual congestion data defined by ADVOR SCORE>1.
Who cannot join
- Systolic blood pressure <90 mmHg or mean arterial pressure < 65 mmHg.
- Maintenance treatment with acetazolamide/ Treatment with acetazolamide in the month prior to inclusion in the study.
- Anticipated need for intravenous inotropes, vasopressors or nitroprusside during the study.
- Contraindication to ISGLT2.
- Type 1 diabetes mellitus
- GFR < 20 ml/min/m2 or renal replacement therapy/ultrafiltration at any time prior to the study.
Show all 16Show fewer
- Anticipated exposure to nephrotoxic agents, such as iodinated contrast during admission.
- Concurrent diagnosis of acute coronary syndrome.
- History of congenital heart disease requiring surgical correction.
- History of cardiac transplantation and/or ventricular assist device.
- Pregnant or breastfeeding patients.
- Inability to adequately collect diuresis.
- Serum potassium less than 3.5 mEq/L.
- Venous pH <7.30
- Severe aortic stenosis or obstructive hypertrophic cardiomyopathy.
- Sulfonamide allergy, liver cirrhosis, renal lithiasis.
Trial locations and contacts
1 site in 1 country. Contact the study team or a site near you to ask about taking part.
Spain1 site, 1 recruiting
- Recruiting
Julia González González
Madrid, 28222
Julia González González, 0034617453693, juliagfk@gmail.com
About this study
Official title: SANDI STUDY: Effect of Acetazolamide on Diuresis and Natriuresis in Patients With Acute Heart Failure.
The goal of this observational study is to assess the natriuretic effect of intravenous acetazolamide in patients admitted with heart failure and persistent congestion despite treatment with intravenous furosemide and sodium-glucose cotransporter type 2 (iSGLT2) inhibitors.
The main question it aims to answer is whether there is a difference in natriuresis 24 hours after acetazolamide association to medical treatment recommended by the guidelines (furosemide and ISGLT2).
Read the detailed description
The SANDY study is a prospective, multicenter, observational study that will be conducted across 11 hospitals in Spain. It will enroll patients hospitalized for AHF presenting with clinical evidence of fluid overload. The study will evaluate natriuresis at 24 and 48 hours following intravenous acetazolamide administration in patients with persistent congestion despite treatment with intravenous furosemide and an SGLT2i. Upon admission, all patients will receive intravenous loop diuretics according to current European guideline recommendations. For those not previously treated with an SGLT2i, therapy will be initiated within the first 24 hours. Congestion will be reassessed 24 hours after combined loop diuretic and SGLT2i therapy. In line with the ADVOR trial, patients with persistent congestion (ADVOR score > 1) will receive intravenous acetazolamide (500 mg once daily) for up to two consecutive days.
During hospitalization and follow-up, participants will be encouraged to limit their daily dietary sodium and fluid intake to 3 g and 1500 ml, respectively.
- Conditions
- Heart Failure, Persistent Congestion
- Being tested
- Acetazolamide 500mg
- Keywords
- Acetazolamide
- Medical subject headings
- Heart Failure
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Acetazolamide 500mgDrug
Patients hospitalized with decompensated heart failure and fluid overload who require diuretic treatment for relieve of congestion. Standarized diuretic protocol according to guidelines will be applied. It consists of intravenous furosemide, SGLT2 inhibitors and acetazolamide if congestion persist.
| Study group | Role | What they receive |
|---|---|---|
| Hospitalized heart failure patients | Patients hospitalized with decompensated heart failure and fluid overload who require diuretic treatment for relieve of congestion. Standarized diuretic protocol according to guidelines will be applied, including loop diuretic and sodium-glucose cotransporter-2 inhibitors (SGLT2i) Receives: Drug: Acetazolamide 500mg |
What is being measured
The primary outcome is the main question the study is designed to answer.
Change in natriuresis 24 hours after acetazolamide
Change in natriuresis (mmol) 24 hours after acetazolamide association to medical treatment recommended by the guidelines (furosemide and ISGLT2).
Measured: 24 hours
Secondary outcomes (10)
Increase in diuresis 24 hours after acetazolamide administration
Increase in diuresis 24 hours after acetazolamide administration (liters)
Measured: 24 hours
Weight difference 24 hours after acetazolamide administration
Weight difference 24 hours after acetazolamide administration (Kg)
Measured: 24 hours
Difference in congestion score 24 hours after acetazolamide administration.
Difference in congestion score 24 hours after acetazolamide administration using ADVOR congestion score. It is a 0-10 scale used in the ADVOR trial to objectively quantify volume overload in acute heart failure, based on three components: peripheral edema scored from 0 to 4 points, pleural effusion from 0 to 3 points, and ascites from 0 to 3 points. A total score of 0 represents the absence of measurable congestion, while the maximum of 10 indicates severe, multisite fluid accumulation. Higher ADVOR scores reflect more severe congestion.
Measured: 24 hours
Difference in ultrasound measurement of Inferior Vena Cava 24 hours after acetazolamide administration.
Difference in inferior vena cava size (mm) assessed by ultrasound, he IVC is visualized in the subcostal long-axis view, and its diameter is measured about 1-2 cm from its junction with the right atrium, 24 hours after acetazolamide administration
Measured: 24 hours
Change in natriuresis 48 hours after acetazolamide administration
Change in natriuresis 48 hours after acetazolamide administration
Measured: 48 hours
Change in diuresis 48 hours after acetazolamide administration
Change in diuresis 48 hours after acetazolamide administration
Measured: 48 hours
Weight difference 48 hours after acetazolamide administration
Weight difference 48 hours after acetazolamide administration
Measured: 48 hours
Difference in congestion score 48 hours after acetazolamide administration.
Difference in congestion score 48 hours after acetazolamide administration using ADVOR congestion score. It is a 0-10 scale used in the ADVOR trial to objectively quantify volume overload in acute heart failure, based on three components: peripheral edema scored from 0 to 4 points, pleural effusion from 0 to 3 points, and ascites from 0 to 3 points. A total score of 0 represents the absence of measurable congestion, while the maximum of 10 indicates severe, multisite fluid accumulation. Higher ADVOR scores reflect more severe congestion.
Measured: 48 hours
Difference in ultrasound measurement of Inferior Vena Cava 48 hours after acetazolamide administration.
Difference in inferior vena cava size (mm) assessed by ultrasound. The IVC is visualized in the subcostal long-axis view, and its diameter is measured about 1-2 cm from its junction with the right atrium, 48 hours after acetazolamide administration
Measured: 48 hours
Change in Vexus score 24 hours after acetazolamide administration.
Vexus score: The VExUS score (Venous Excess Ultrasound Score) is an ultrasound-based grading system used to assess systemic venous congestion by integrating measurements of the inferior vena cava (IVC) and Doppler patterns of key abdominal veins: the hepatic vein, portal vein, and intrarenal vein. A dilated IVC combined with progressively abnormal venous Doppler waveforms indicates increasing venous congestion. VExUS is typically graded from 0 to 3, where Grade 0 represents no significant congestion and Grade 3 indicates severe venous congestion with markedly abnormal waveforms across multiple veins. Higher VExUS correlates with worse outcomes.
Measured: 24 h post acetazolamide administration
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted29 Feb 2024
- Study start1 Mar 2024
- Primary completion31 May 2026 (estimated)
- Study completion31 Dec 2026 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Heart FailureStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Observational
- Observational model
- Cohort
- Time perspective
- Prospective
- Enrolment
- 64 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Puerta de Hierro University Hospital
- Sponsor type
- University, hospital or other
- Collaborators
- Hospital Clinic of Barcelona, Hospital Central de la Defensa Gómez Ulla, Hospital Vall d'Hebron, Hospital Universitario Ramon y Cajal, University Hospital of Girona Dr. Josep Trueta, Fundación de Investigación Biomédica - Hospital Universitario de La Princesa
- Responsible party
- Principal investigator, Julia Gonzalez, Puerta de Hierro University Hospital
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT06285760
- Sponsor's protocol ID
- 135/23
- Acronym
- SANDI
- Status last verified
- Dec 2025
- First submitted
- 8 Jan 2024
- Last updated
- 29 Dec 2025
- Results posted
- No
- Data monitoring committee
- Yes
- FDA-regulated drug
- Yes
- FDA-regulated device
- No
Study at a glance
From the registry record, last updated by the sponsor on 29 Dec 2025. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- SANDI STUDY: Effect of Acetazolamide on Diuresis and Natriuresis in Patients With Acute Heart Failure.
- ClinicalTrials.gov ID
- NCT06285760
- Acronym / sponsor ID
- SANDI / 135/23
- Conditions
- Heart Failure, Persistent Congestion
- Keywords
- Acetazolamide
- Study type
- Observational
- Recruitment status
- Recruiting
- Enrolment
- 64 participants (estimated)
- Lead sponsor
- Puerta de Hierro University HospitalUniversity, hospital or other
- Collaborators
- Hospital Clinic of Barcelona, Hospital Central de la Defensa Gómez Ulla, Hospital Vall d'Hebron, Hospital Universitario Ramon y Cajal, University Hospital of Girona Dr. Josep Trueta, Fundación de Investigación Biomédica - Hospital Universitario de La Princesa
- Study start
- 1 Mar 2024 (actual)
- Primary completion
- 31 May 2026 (estimated)
- Study completion
- 31 Dec 2026 (estimated)
- First posted
- 29 Feb 2024 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
The goal of this observational study is to assess the natriuretic effect of intravenous acetazolamide in patients admitted with heart failure and persistent congestion despite treatment with intravenous furosemide and sodium-glucose cotransporter type 2 (iSGLT2) inhibitors.
The main question it aims to answer is whether there is a difference in natriuresis 24 hours after acetazolamide association to medical treatment recommended by the guidelines (furosemide and ISGLT2).
Detailed description
The SANDY study is a prospective, multicenter, observational study that will be conducted across 11 hospitals in Spain. It will enroll patients hospitalized for AHF presenting with clinical evidence of fluid overload. The study will evaluate natriuresis at 24 and 48 hours following intravenous acetazolamide administration in patients with persistent congestion despite treatment with intravenous furosemide and an SGLT2i. Upon admission, all patients will receive intravenous loop diuretics according to current European guideline recommendations. For those not previously treated with an SGLT2i, therapy will be initiated within the first 24 hours. Congestion will be reassessed 24 hours after combined loop diuretic and SGLT2i therapy. In line with the ADVOR trial, patients with persistent congestion (ADVOR score > 1) will receive intravenous acetazolamide (500 mg once daily) for up to two consecutive days.
During hospitalization and follow-up, participants will be encouraged to limit their daily dietary sodium and fluid intake to 3 g and 1500 ml, respectively.
Study design
- Observational model
- Cohort
- Time perspective
- Prospective
- Number of arms
- 1
| Arm | Type | Receives |
|---|---|---|
| Hospitalized heart failure patients | – | Drug: Acetazolamide 500mgPatients hospitalized with decompensated heart failure and fluid overload who require diuretic treatment for relieve of congestion. Standarized diuretic protocol according to guidelines will be applied, including loop diuretic and sodium-glucose cotransporter-2 inhibitors (SGLT2i) |
Who may qualify
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Child, Adult, Older adult
- Study population
- Patients admitted for heart failure with persistent findings of residual congestion who meet the inclusion criteria and none of the exclusion criteria.
Key inclusion criteria (3 listed)
- Patients admitted for acute heart failure and ≥ 1 clinical sign of volume overload (edema, ascites, or pleural effusion).
- NTproBNP levels >1000 pg/mL or BNP >250 ng/mL on admission.
- Under treatment with furosemide and iSGLT2 according to European guidelines and indication of association of another diuretic due to residual congestion data defined by ADVOR SCORE>1.
Key exclusion criteria (16 listed)
- Systolic blood pressure <90 mmHg or mean arterial pressure < 65 mmHg.
- Maintenance treatment with acetazolamide/ Treatment with acetazolamide in the month prior to inclusion in the study.
- Anticipated need for intravenous inotropes, vasopressors or nitroprusside during the study.
- Contraindication to ISGLT2.
- Type 1 diabetes mellitus
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Acetazolamide 500mgPatients hospitalized with decompensated heart failure and fluid overload who require diuretic treatment for relieve of congestion. Standarized diuretic protocol according to guidelines will be applied. It consists of intravenous furosemide, SGLT2 inhibitors and acetazolamide if congestion persist. | Drug | Hospitalized heart failure patients |
Primary outcome
Change in natriuresis 24 hours after acetazolamide
Time frame: 24 hours
Change in natriuresis (mmol) 24 hours after acetazolamide association to medical treatment recommended by the guidelines (furosemide and ISGLT2).
10 secondary outcomes
Increase in diuresis 24 hours after acetazolamide administration
Time frame: 24 hours
Weight difference 24 hours after acetazolamide administration
Time frame: 24 hours
Difference in congestion score 24 hours after acetazolamide administration.
Time frame: 24 hours
Difference in ultrasound measurement of Inferior Vena Cava 24 hours after acetazolamide administration.
Time frame: 24 hours
Change in natriuresis 48 hours after acetazolamide administration
Time frame: 48 hours
Change in diuresis 48 hours after acetazolamide administration
Time frame: 48 hours
Weight difference 48 hours after acetazolamide administration
Time frame: 48 hours
Difference in congestion score 48 hours after acetazolamide administration.
Time frame: 48 hours
Difference in ultrasound measurement of Inferior Vena Cava 48 hours after acetazolamide administration.
Time frame: 48 hours
Change in Vexus score 24 hours after acetazolamide administration.
Time frame: 24 h post acetazolamide administration
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 29 Dec 2025.
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part.
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
An observational study of Heart Failure and Persistent Congestion, run by Puerta de Hierro University Hospital at 1 site in Spain.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 3 inclusion and 16 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: looking for participants now, as of the sponsor's last update on 29 Dec 2025. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in Spain. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
Contact Julia González González (0034617453693, juliagfk@gmail.com), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Change in natriuresis 24 hours after acetazolamide (time frame: 24 hours). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 29 Dec 2025; AzTrials last refreshed its copy on 8 Nov 2026.