Extracorporeal veno-venous ultrafiltration in patients with acute heart failure

Hospitalization for congestive heart failure represents a growing burden for health care systems. Heart failure is characterized by extracellular fluid overload and loop diuretics have been for decades the cornerstone of therapy in these patients. However, extensive use of intra-venous diuretics is characterised by several limitations: risk of worsening renal function and electrolyte imbalance, symptomatic hypotension and development of diuretic resistance. Extracorporealveno-venous ultrafiltration (UF) represents an interesting adjunctive therapy to target congestion in patients with heart failure and fluid overload. UF consists of the mechanical removal of iso-tonic plasma water from the blood through a semipermeable membrane using a pressure gradient generated by a pump. Fluid removal through UF presents several advantages such as removal of higher amount of sodium, predictable effect, limited neuro-hormonal activation, and enhanced spontaneous diuresis and diuretic response. After twenty years of "early" studies, since 2000 some pilot studies and randomized clinical trials with modern devices have been carried out with somehow conflicting results, as discussed in this review. In addition, some practical aspects of UF are addressed.