Ultrafiltration in heart failure

Fluid overload is a key pathophysiologic mechanism underlying both the acute decompensation episodes of heart failure and the progression of the syndrome. Moreover, it represents the most important factor responsible for the high readmission rates observed in these patients and is often associated with renal function worsening, which by itself increases mortality risk. In this clinical context, ultrafiltration (UF) has been proposed as an alternative to diuretics to obtain a quicker relief of pulmonary/systemic congestion. This review illustrates technical issues, mechanisms, efficacy, safety, costs, and indications of UF in heart failure. The available evidence does not support the widespread use of UF as a substitute for diuretic therapy. Owing to its operative characteristics, UF cannot be expected to directly influence serum electrolyte levels, azotemia, and acid-base balance, or to remove high-molecular-weight substances (eg, cytokines) in clinically relevant amounts. Ultrafiltration should be used neither as a quicker way to achieve a sort of mechanical diuresis nor as a remedy for an inadequately prescribed and administered diuretic therapy. Instead, it should be reserved to selected patients with advanced heart failure and true diuretic resistance, as part of a more complex strategy aiming at an adequate control of fluid retention.