Congestive heart failure (CHF) remains a major cause of morbidity, rehospitalization, and mortality worldwide, particularly among elderly and polymorbid patients. Systemic congestion is its most characteristic clinical manifestation and the leading cause of hospitalization for acute heart failure. Standard treatment relies on loop diuretics, primarily furosemide, to reduce fluid overload and alleviate congestive symptoms. However, in clinical practice, many patients exhibit an inadequate diuretic response or resistance to furosemide, particularly in the context of cardiorenal syndrome (CRS), where cardiac and renal dysfunction mutually exacerbate each other. This profile, frequently observed in advanced stages of heart failure, significantly limits the effectiveness of guideline-directed medical therapies (GDMTs), particularly SGLT2 inhibitors, mineralocorticoid receptor antagonists, and angiotensin-converting enzyme (ACE) inhibitors, whose use is often restricted by hypotension, hyperkalemia, or impaired renal function.

Thus, in this subgroup of patients, conventional pharmacological approaches encounter a therapeutic barrier, necessitating the search for alternative or complementary strategies targeting sodium and water depletion without compromising renal perfusion. In this context, the combined administration of hypertonic saline (HS) and furosemide has been proposed as a pathophysiologically sound approach to break the vicious cycle of cardiorenal syndrome. Hypertonic saline solution (HSS) acts by restoring effective intravascular volume, improving renal perfusion, and promoting more efficient natriuresis through better furosemide delivery to the distal nephron. Pioneering studies by Paterna et al. showed that the concomitant administration of HSS (1.4-3% NaCl, 150-250 mL) and intravenous furosemide increased diuresis, improved the hemodynamic profile, and reduced the length of hospital stay and readmission rates without deterioration of renal function.

Inclusion Criteria:

• Age ≥ 18 years
• Chronic renal insufficiency (serum creatinine > 150 µg/ml)
• Diagnosis of heart failure (preserved or reduced LVEF)
• Signed informed consent

Exclusion Criteria:

• Severe hyponatremia (<130 mmol/L) or hypernatremia (>150 mmol/L),
• History of allergic reaction to HSS or furosemide
• Shock or hemodynamic instability
• Pregnancy or breastfeeding
• Chronic dialysis treatment
• Patient refusal or withdrawal of consent

PD will not be shared due to concerns related to patient confidentiality and data privacy