Treatment of congestion in heart failure with diuretics and extracorporeal therapies: effects on symptoms, renal function, and prognosis.

In the United States and Europe, approximately 90% of heart failure hospitalizations are due to symptoms and signs of sodium and fluid excess. Congestion is associated with heart failure progression. Venous congestion, rather than a reduced cardiac output, may be the primary hemodynamic factor driving worsening renal function in patients with acutely decompensated heart failure. According to data from large national registries, approximately 40% of hospitalized heart failure patients are discharged with unresolved congestion, which may contribute to unacceptably high re-hospitalization rates. Diuretics reduce the symptoms and signs of fluid overload, but their effectiveness can be reduced by excess salt intake, underlying chronic kidney disease, renal adaptation to their action, and neurohormonal activation. In addition, the production of hypotonic urine limits the ability of loop diuretics to reduce total body sodium. Ultrafiltration is the mechanical removal of fluid from the vasculature. Hydrostatic pressure is applied to blood across a semipermeable membrane to separate isotonic plasma water from blood. Because solutes in blood freely cross the semipermeable membrane, fluid can be removed without causing significant changes in the serum concentration of electrolytes and other solutes. Relatively small, mostly single-center clinical studies of ultrafiltration have shown that removal of isotonic fluid may relieve symptoms of congestion and restore diuretic responsiveness in patients with diuretic resistance. These studies have also shown a favorable effect on neurohormonal activation. When compared with intravenous diuretics, ultrafiltration similarly changed dyspnea scores but reduced re-hospitalizations (28 of 87 patients (32%) versus 16 of 89 patients (18%), P < 0.037) in a randomized controlled trial of patients with decompensated heart failure. Future larger controlled clinical trials should evaluate further the effect of ultrafiltration on patients' outcomes, including survival.