Improved cardiovascular variables during acetate free biofiltration

Acetate free biofiltration (AFB) provides a well-tolerated and efficient renal replacement therapy. Replacement of most of the acetate by bicarbonate in standard hemodialysis has resulted in a decrease in intradialytic hypotensive episodes. This has been attributed to a decrease in the acetate-induced impairment of myocardial contractility. The aim of the present study was to investigate whether the total absence of acetate in AFB would further enhance dialysis stability and improve cardiovascular status.

In a long-term, randomized trial we included 11 patients on AFB and 9 patients on bicarbonate hemodialysis (HD) for one year. Patients were matched for age, sex and urea reduction rate, but not for the presence of hypertension or cardiovascular history. During each dialysis session blood pressure was measured automatically and the presence of significant hypotension was recorded. Antihypertensive medication was registered every three months. Before and at the end of the study M-mode echocardiography was performed and left ventricular mass index (LVMi) was calculated. Every six months serum lipids were measured.

At baseline, mean arterial pressure (MAP) before and after dialysis, the percentage of hypotensive dialyses, LVMi and serum lipids did not differ between AFB and HD. Pre-dialysis MAP decreased in AFB (from 112.5 to 107 mmHg) and increased in HD (from 101.7 to 105.3 mmHg; p = 0.01, HD versus AFB). Postdialysis MAP remained stable in both groups (AFB 91.6 mmHg at 0 months and 90.6 mmHg at 12 months, for HD respectively 83.9 and 86.5 mmHg, NS). The percentage of hypotensive dialyses did not differ significantly between the groups during the study. LVMi decreased in AFB from 195.4 to 162.1 gr/m2 and increased in HD patients from 153.8 to 182.5 gr/m2 (p = 0.03 HD versus AFB). The number of antihypertensive medications per patient did not differ between groups. Serum lipids remained unchanged during the trial.

In conclusion, AFB provided better control of pre-dialysis MAP compared to HD, and stable postdialysis MAP. The percentage of dialysis sessions with hypotension did not differ. LVMi decreased significantly in AFB, but rose in HD.