Clinical and Subclinical Congestion in Acute Heart Failure: Prevalence, Evolution, Correlations, and Prognostic Impact

Background/Objectives: Congestion is a hallmark of heart failure (HF) and a major determinant of outcomes. Non-invasive tools enable detection of subclinical congestion, but their correlation and prognostic relevance remain incompletely defined. We aimed to assess the prevalence, evolution, interrelationship, and prognostic impact of clinical and subclinical congestion markers in patients hospitalized for HF. Methods: This single-centre, prospective cohort study included adults admitted with HF who underwent serial evaluations at admission, 72 hours, pre-discharge, early outpatient follow-up and at 6-month. Clinical congestion was assessed using a standardized physical examination score. Subclinical congestion was evaluated using lung ultrasound (LUS), Venous Excess Ultrasound Score (VExUS), and Remote Dielectric Sensing (ReDS). Patients were classified according to the presence of clinical and/or subclinical congestion at discharge. The primary endpoint was a composite of all-cause mortality, HF readmission, or unscheduled visits requiring intravenous diuretics within six months of follow-up. Results: Ninety-four patients (mean age 74±11 years, 68% male) were included. While clinical congestion improved significantly during hospitalization, approximately 30% of patients remained clinically congested at discharge. Among clinically euvolemic patients, only 47% showed no evidence of subclinical congestion. Correlations between congestion markers were weak to moderate, suggesting complementary pathophysiological information. At discharge, pulmonary B-lines were the strongest predictor of the composite endpoint (hazard ratio [HR] 3.50, 95% CI 1.41–8.72), followed by clinical congestion (HR 2.67, 95% CI 1.13–6.30). Patients with both clinical and subclinical congestion had the lowest event-free survival, approximately 50% at six months of follow-up (log-rank p = 0.03). Conclusions: Subclinical congestion is common despite apparent clinical euvolemia and is associated with worse outcomes. Integrating clinical assessment with non-invasive congestion markers may improve post-discharge risk stratification and patient management in HF.