Acetate-free biofiltration in the long-term treatment of elderly patients

Purpose. We evaluated acetate-free biofiltration (AFB) in elderly patients. Methods. Four patients (1 without diabetes and 3 with diabetes, age 71+/-2 years) were switched to AFB because symptomatic intradialytic hypotension had occurred with offline hemodiafiltration (HDF). During 2 years of treatment with AFB, we monitored biochemical parameters, mtradialytic mean arterial pressure (MAP), and extradialytic symptoms. Results. Pre- and postdialysis plasma bicarbonate concentrations were significantly higher during AFB than conventional HDF (21.3 vs. 19.6 mmol/L; p=0.039, 25.8 vs. 22.3 nunol/L; p<0.0001). Pre- and postdialysis serum beta(2)-microglobulin was significantly lower during AFB than conventional HDF (30.7 vs. 35.7 mg/dl; p=0.0013, 11.7 vs. 21.4 mg/dl; p=0.0005). Over 2 years, substitution of AFB elevated intradialytic MAP (114.5 vs. 95.5 mm Hg; p<0.0001), decreased cardiovascular collapse occurrence by 24.8%, and reduced extradialytic symptoms (p= 0.005) compared to conventional HDF. Addition of potassium to dialysate was needed to treat low postdialysis serum potassium over 6 months of treatment with AFB. Conclusions. Our findings suggest that AFB provides optimal correction of metabolic acidosis in elderly patients, significantly enhancing cardiovascular stability. AFB also accomplishes better removal of beta(2)-microglobulin than conventional HDF.