On-line hemofiltration in chronic renal failure: advantages and limits

The actual dialysis therapy offers a notable long-term survival and rehabilitation, but it is still far from normalizing the patient's quality of life as well as mortality and morbidity. The most widely used dialysis therapy is an almost exclusive diffusive treatment performed with low-flux cellulose memb­ranes with a dialysis dose targeted to a urea Kt/V of 1.2 or higher. The convective treatments, which use high­flux membranes, offer proven biological superiority over diffusive treatments, which are performed with bio-incompatible, low­flux membranes. Retrospective epidemiolo­gical studies have documented a reduction of morbidity and mortality with the use of high-flux membranes, but the results of the prospective studies comparing low-flux with high-flux treatments are still con­flicting. Cardiovascular instability during treatment sessions is a potential cause of morbidity and mortality for patients on dialysis treatment. Hemofiltration (HF) is a pure convective treatment and offers the best tolerance to fluid subtraction in hemo­dynamically unstable patients. Because of its limitation in removing urea as well as high costs, HF treatment is restricted to few high risk unstable patients. The modern pre­dilution HF, performed with ultrapure on­line prepared solutions, overcomes, at least partially, the above limitation, but there is scarcity of data evaluating its long-term efficacy in stable patients.