Acute heart failure (AHF) is a leading cause of hospitalization and is associated with high short-term morbidity and mortality, with 20-30% of patients experiencing rehospitalization or death within 30 days. Early adverse events often reflect incomplete recovery, highlighting the need for improved risk stratification after clinical stabilization .Current prognostic approaches mainly focus on hemodynamic congestion. Persistent pulmonary congestion at discharge is a strong predictor of poor outcomes, but these markers primarily assess macrocirculatory abnormalities and do not capture microcirculatory dysfunction, which may persist despite apparent clinical improvement. Lung ultrasound, through the Lung Ultrasound Score (LUS), provides a validated assessment of pulmonary congestion and has demonstrated prognostic value in AHF. However, LUS does not reflect systemic tissue perfusion. In contrast, blood lactate is a robust marker of tissue hypoperfusion, and even mild elevations have been associated with worse outcomes in AHF. A combined score integrating LUS and lactate may therefore better reflect the dual pathophysiology of AHF-persistent congestion and impaired tissue perfusion-and improve prediction of early adverse events.

This protocol aims to validate the prognostic value of this combined score for predicting 30-day rehospitalization or death in patients hospitalized for AHF, with the hypothesis that it outperforms LUS alone.

This is a prospective, multicenter, observational cohort study including adults (≥18 years) hospitalized for acute decompensated heart failure who were deemed clinically stable and scheduled for discharge within 24 hours. Patients with active severe infection or septic shock, significant hypoxemia or respiratory distress requiring advanced oxygen or ventilatory support, advanced liver disease, refusal to participate, or technical inability to perform lung ultrasound were excluded. At discharge, pulmonary congestion was assessed using lung ultrasound with a standardized 8-zone protocol, and venous blood lactate was measured under resting conditions. Demographic data, heart failure phenotype, discharge vital signs, laboratory values, treatments, and hospitalization characteristics were collected. The primary endpoint was a composite of heart failure-related readmission or all-cause mortality within 30 days after discharge. Secondary endpoints included all-cause readmission, emergency department visits at 30 days, and time to first event. Follow-up was conducted at 30 days using a standardized telephone interview and review of medical records, with strict criteria applied for the definition of heart failure readmission.

Inclusion Criteria:

• Age ≥ 18 years.
• Hospitalization for acute heart failure/decompensation (clinical diagnosis + imaging/laboratory tests according to local practice).
• Patient deemed ready for discharge (decision made by the team, discharge within 24 hours).

Exclusion Criteria:

• Septic shock/severe active infection at the time of discharge.
• Hypoxemia or respiratory distress requiring high-flow oxygen/ventilation at the scheduled time of discharge.
• Severe cirrhosis/advanced liver failure.
• Refusal to participate.
• Technical impossibility of LUS.

Patients Hospitalized for Acute Decompensated Heart Failure:

Adults admitted due to worsening heart failure symptoms requiring inpatient management, including clinical and/or imaging or laboratory confirmation of decompensation.