Overcoming Residual Congestion in Acute Heart Failure: Defining Targets and Identifying Diuretic Responders

Acute heart failure remains a high-morbidity, high-mortality syndrome with heterogeneous clinical presentations, ranging from congestion, a frequent driver of hospitalization and central therapeutic target, to hypoperfusion and cardiogenic shock in more severe phenotypes. Yet, bedside findings have limited diagnostic accuracy for the diagnosis of acute heart failure, and objective, actionable end points to define adequate decongestion during hospitalization remain poorly standardized. This review synthesizes contemporary evidence across the spectrum of congestion in acute heart failure, clinical, subclinical, and residual, and summarizes the strengths and limitations of clinical examination, natriuretic peptides and other laboratory markers, and imaging modalities (chest radiography, lung ultrasound, echocardiographic Doppler indices, inferior vena cava assessment) for identifying congestion and tracking response to therapy. We highlight persistent residual congestion as a common discharge phenotype consistently linked to adverse outcomes, while emphasizing why prior biomarker- and imaging-guided strategies have not yet produced definitive outcome improvements. Finally, we propose a profile-based approach that integrates residual congestion (the manifestation of decongestive effort at a given time point) with diuretic resistance (the underlying cardio-renal/sodium-handling substrate) to better identify who will respond, who requires early escalation, and how to personalize decongestive intensity and postdischarge surveillance.