The complexity of congestion in heart failure: a critical review of the evidence and a proposal for a multimodality approach.

Congestion remains the first cause of hospitalization in acute heart failure patients, and it is the primary goal of treatment during early phases of hospitalization. Despite its clinical relevance, a universal algorithm for quantification or characterization is lacking. Indeed, congestion has been differently evaluated across several studies in terms of timing checks and diagnostic methods. Recent analyses have highlighted the importance of differentiating between intravascular and tissue congestion. Although it is associated with haemodynamic dysfunction, extravascular congestion may occur even in the absence of overt intravascular fluid overload. Importantly, tissue congestion is not merely a reflection of intravascular volume expansion. In this framework, the interstitial space surrounding the capillary barrier and its integrity may be accounted as additive drivers for tissue congestion. In clinical practice, this distinction remains anchored in simplistic clinical assessment, and poorly evaluated. A critical review of the evidences has been performed and multimodal approaches combining ultrasonography, invasive measurements, and biomarkers have been proposed.