Congestion occurrence and evaluation in acute heart failure scenario: time to reconsider different pathways of volume overload

Although congestion is considered to be the main reason for hospital admission in patients with acute heart failure, a simplistic view considering idro saline retention and total body volume accumulation did not provide convincing data. Clinical congestion occurrence is often the tip of the iceberg of several different mechanisms ranging from increased filling pressure to extravascular fluid accumulation and blood flow redistribution. Therefore, the clinical evaluation is often restricted to a simple physical examination including few and inaccurate signs and symptoms. This superficial approach has led to contradictory data and patients have not been evaluated according to a more realistic clinical scenario. The integration with new diagnostic ultrasonographic and laboratory tools would substantially improve these weaknesses. Indeed, congestion could be assessed by following the most recognized HF subtypes including primitive cardiac defect, presence of right ventricular dysfunction, and organ perfusion. Moreover, there is a tremendous gap regarding the interchangeable concept of fluid retention and redistribution used with a univocal meaning. Overall, congestion assessment should be revised, considering it as either central, peripheral, or both. In this review, we aim to provide different evidence regarding the concept of congestion starting from the most recognized pathophysiological mechanisms of AHF decompensation. We highlight the fact that a better knowledge of congestion is a challenge for future investigation and it could lead to significant advances in HF treatment.