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NCT Number: NCT07468344

Evaluation of the Effects of Sauna Therapy on Congestion and Loop Diuretic Use in Patients With Heart Failure With Reduced or Moderately Reduced Ejection Fraction

This study aims to evaluate the effect of sauna therapy on congestion levels during cardiac rehabilitation in patients with heart failure who have an impaired or moderately impaired ejection fraction, compared to standard cardiac rehabilitation care. To investigate this, patients with reduced cardiac function who are hospitalized as part of a cardiac rehabilitation program will be included. These patients will be randomly assigned to two groups: standard cardiac rehabilitation program (control group) and sauna group (intervention group). The study will also assess whether this approach could allow for a reduction in the dose of diuretics, which are commonly used to remove excess fluid, thereby helping to avoid certain side effects. The expected benefits include a reduction in symptoms such as shortness of breath and swelling, improvements in quality of life and physical fitness, and enhanced blood vessel function.

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Key information

Conditions

Heart Failure Cardiovascular Diseases Heart Diseases

Age range

18 year and older

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • Age ≥ 18 years.
  • Heart failure with ejection fraction <50% confirmed by an echocardiogram within the past year.
  • NYHA class II-III.
  • Loop diuretic dose ≥ 40 mg/day of furosemide (or equivalent) for at least 30 days.
  • NT-proBNP > 400 pg/ml or BNP > 100 pg/ml.
  • Systolic blood pressure ≥ 100 mmHg.
  • Estimated glomerular filtration rate (eGFR) ≥ 20 ml/min/1.73 m².
  • Patient scheduled for a hospital-based cardiac rehabilitation program for a minimum of 3 weeks.
  • Person who has undergone a preliminary clinical examination suitable for clinical research.
  • Person affiliated with a social security system or a beneficiary of such a system.
  • Person who has received complete information about the organization of the clinical research and has signed informed consent.

Exclusion criteria

  • Person presenting a contraindication to sauna therapy (for example, intolerance to heat).
  • Serum sodium < 130 mmol/L.
  • Serum potassium > 5.5 mmol/L.
  • Active infection, liver disease, or peripheral vascular disease.
  • Acute coronary syndrome or recent stroke (<90 days).
  • Participation in another interventional clinical trial.
  • Person subject to Articles L. 1121-5, L. 1121-7, and L. 1121-8 of the Public Health Code (applicable in France) :- pregnant, giving birth, or breastfeeding woman , minor (non-emancipated), person adult subject to a legal protection measure (guardianship, curatorship, judicial protection) , adult unable to express consent, persons deprived of liberty by judicial or administrative decision, persons receiving psychiatric care under Articles L. 3212-1 and L. 3213-1…

Treatment and study plan

Sauna

Device

A 15-minute sauna session at 60 degrees Celsius, five times a week for three weeks during hospitalization for cardiac rehabilitation. The sauna sessions will be followed by 30 minutes of recovery in a seated position. In addition to the sauna, patients will benefit from cardiac rehabilitation care for 3 weeks.

Primary outcomes

  1. Median change in NT-proBNP levels.

    Time frame: Between randomization and the end of the third week.

Secondary outcomes

  1. Daily dose of loop diuretics.

    Time frame: Day 1, end of weeks 1, 2, and 3, and 3-month follow-up.

  2. Weight in kilograms.

    Time frame: Day 1, end of weeks 1,2 and 3, and 3-month follow-up.

  3. Congestion score: ADVoR congestion score.

    Time frame: Day 1, end of week 3, and 3-month follow-up.

    ADVoR congestion score is a grading scale taking account oedema, pleural effusion and ascites. The score can range from 0 to 10 with "0" being the best result meaning " no congestion " and "10" the worst meaning " maximum congestion ".

  4. Congestion score: Ambrosy congestion score.

    Time frame: Day 1, end of week 3, and 3-month follow-up.

    Ambrosy congestion score is a grading scale taking account dyspnoea, orthopnoea, jugular venous distension, rales and oedema.

    The score can range from 0 to 18, "0" being the best outcome (no congestion) and "18" the worst outcome (maximum congestion).

  5. Estimated plasma volume (EPV): Duarte formula.

    Time frame: Day 1, end of week 3, and 3-month follow-up.

  6. Dyspnea visual analog scale: Cumulative dyspnea assessment (AUC).

    Time frame: Day 1, beginning of weeks 2 and 3.

    The minimum value is "0" (best outcome) and means "no dyspnea". The maximum value is "10" (worst outcome) and means "maximum dyspnea".

  7. Concentration of natriuretic peptides (NT-proBNP).

    Time frame: Day 1, end of week 1, beginning and end of week 2, beginning and end of week 3, and 3-month follow-up.

  8. Evaluation of renal function through rate of serum creatinine allowing to estimate glomerular filtration rate.

    Time frame: End of weeks 1, 2, and 3 and 3-month follow-up.

    Estimate glomerular filtration rate is calculated by the following formula :

    Clearance (mL/min) = weight (kg) x (140-age) x K / serum creatinine (μmol/L) ; K=1.23 for man and 1.04 for woman.

  9. Evaluation of renal function through renal function assessment.

    Time frame: Day 1 and end of week 3.

  10. Dose of diuretics.

    Time frame: Day 1, end of weeks 1, 2, and 3, and 3-month follow-up.

  11. Concentration of serum electrolytes (Cl-, Na+, K+).

    Time frame: Day 1, end of weeks 1, 2, and 3, and 3-month follow-up.

  12. Blood osmolality in mmol/L.

    Time frame: Day 1, end of weeks 1, 2, and 3, and 3-month follow-up.

    Blood osmolality in mmol/L is calculated using natremia, glycemia and uremia. The formula is : Natremia in mmmol/L*2 + glycemia in mmol/L *5.56 + uremia in mmol/L*16.6.

  13. Concentration of urinary electrolytes (Cl-, Na+, K+).

    Time frame: Day 1, end of weeks 1, 2, and 3, and 3-month follow-up.

  14. Urinary osmolality in mmol/L.

    Time frame: Day 1, beginning and end of weeks 1, 2, and 3, and 3-month follow-up.

    Urinary osmolality in mmol/L is calculated using natremia, glycemia and uremia. The formula is : (natremia in mmol/L + kaliemia in mmol/L+ chloride in mmol/L) + (glycemia in mmol/L*5.56) + (uremia in mmol/L*16.6).

  15. Hemoconcentration biomarkers : Hct.

    Time frame: Day 1, end of weeks 1, 2, and 3, and 3-month follow-up.

    Hemoconcentration was assessed using hematocrit (%).

  16. Hemoconcentration biomarkers : Hb.

    Time frame: Day 1, end of weeks 1, 2, and 3, and 3-month follow-up.

    Hemoconcentration was assessed using hemoglobin (g/dL).

  17. Hemoconcentration biomarkers : total protein.

    Time frame: Time Frame: Day 1, end of weeks 1, 2, and 3, and 3-month follow-up.

    Hemoconcentration was assessed using total protein (g/L).

  18. Hemoconcentration biomarkers : copeptin.

    Time frame: Time Frame: Day 1, end of weeks 1, 2, and 3, and 3-month follow-up.

    Hemoconcentration was assessed using copeptin concentrations (pmol/L).

  19. Inferior vena cava diameter (millimeters, mm) measured by transthoracic echocardiography during inspiration.

    Time frame: Day 1, end of week 1, beginning and end of week 2, beginning and end of week 3, and 3-month follow-up.

    The inferior vena cava (IVC) diameter will be measured in millimeters using transthoracic echocardiography.

  20. Inferior vena cava diameter (millimeters, mm) in expiration measured by transthoracic echocardiography during expiration.

    Time frame: Day 1, end of week 1, beginning and end of week 2, beginning and end of week 3, and 3-month follow-up.

    IVC diameter will be measured in millimeters using transthoracic echocardiography.

  21. Inferior vena cava respiratory variation / collapsibility index (percentage, %) assessed by transthoracic echocardiography.

    Time frame: Day 1, end of week 1, beginning and end of week 2, beginning and end of week 3, and 3-month follow-up.

    VCI respiratory variation will be assessed using transthoracic echocardiography and expressed as the collapsibility index. Collapsibility index will be measured as the ratio between IVC diameter in inspiration (outcome 17) and IVC diameter in expiration (outcome 18) expressed in %.

  22. Lung ultrasound score (8 points).

    Time frame: Day 1, end of week 3, and 3-month follow-up.

    Evaluation of lung comet presence measured by an 8-points lung echography and rated on a scale ranging from 0 (minimum - best outcome : no congestion) to 10 (maximum - worst outcome : maximum congestion) per point.

  23. Quantification of changes in systolic and diastolic function.

    Time frame: Day 1 and 3-month follow-up.

  24. Heart rate in Beats Per Minute (BPM).

    Time frame: Multiple daily measurements : 4 times a day, 5 days a week for 3 weeks.

  25. Heart rate variability in millisecond (ms).

    Time frame: Multiple daily measurements : 4 times a day, 5 days a week for 3 weeks.

  26. Blood pressure in mmHg.

    Time frame: Up to 3 weeks and at 3-month follow-up.

    Blood pressure will be measured daily for 3 weeks and at 3-month follow-up.

  27. Monitoring of changes in pulmonary blood pressure.

    Time frame: Day 1 and at 3-month follow-up.

    Changes in pulmonary blood pressure will be measured with echocardiography.

  28. Composite clinical endpoint of hospitalization or emergency visits for heart failure or all-cause death.

    Time frame: At 3-month follow-up.

  29. Body composition parameters assessed by bioelectrical impedance analysis.

    Time frame: Day 1, end of Week 1, beginning and end of Week 2, beginning and end of Week 3, and at 3-month follow-up.

    Evaluation of the patient's body composition parameters. This measure includes the assessment of fluid distribution-Total Body Water (TBW), Intracellular Water (ICW), and Extracellular Water (ECW)-as well as tissue compartments: body protein mass, body mineral mass, and fat mass. The device records multiple parameters, the analysis will focus specifically on these pre-specified indicators of body composition.

  30. Specific to the sauna group : weight in kilograms.

    Time frame: Up to 3 weeks.

    Weight will be measured before and after each sauna session.

  31. Specific to the sauna group : blood pressure in mmHg.

    Time frame: Up to 3 weeks.

    Blood pressure will be measured before and after each sauna session.

  32. Specific to the sauna group : temperature in °C.

    Time frame: Up to 3 weeks.

    Temperature will be measured before and after each sauna session.

  33. Specific to the sauna group : heart rate in Beats Per Minute (BPM).

    Time frame: Up to 3 weeks.

    Heart rate will be measured continuously during each sauna session.

  34. Specific to the sauna group : sodium chloride concentration in sweat.

    Time frame: Up to 3 weeks.

    The concentration of sodium chloride in sweat will be measured during one sauna session per week (three measurements in total).

Study contacts

Contact information is provided by the study sponsor or research team.

Guillaume Baudry

CONTACT

[email protected]

+33 03 83 15 73 22

Sponsors and collaborators

Lead sponsor

BAUDRY Guillaume

Other

Registry information

Official study title

Impact of Sauna Therapy on Congestion and Loop Diuretic Adjustment in Patients With Heart Failure

Acronym: SAUNA-HF RCT

Important dates

Study start
2026
Primary completion
2027
Study completion
2027
First posted
Mar 12, 2026
Registry last updated
Mar 12, 2026

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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