REMOVAL OF BRANCHED-CHAIN AMINO-ACIDS AND ALPHA-KETOISOCAPROATE BY HEMOFILTRATION AND HEMODIAFILTRATION

Venovenaus haemofiltration (VVHF) and haemodiafiltration (VVHDF) were performed with a neonatal haemo(dia)filter (Miniflow 10, Hospal) on 8 anaesthetized rabbits infused with branched-chain amino acids (leucine , isoleucine and valine) and alpha-ketoisocaproate. The branched-chain amino acids (BCAA) and alpha-ketoisocaproate blood levels were close to those previously observed in neonates with maple syrup urine diseas e when extracorporeal blood purification was required. VVHF and VVHDF performances were assessed with two different blood flows (Q(b) = 8.3 and 16.6 ml/min). VVHDF was performed with four dialysate flowrates (Q (d) = 0.5, 1.0, 2.0 and 3.0L/h). Within each period, clearances of the three BCAA were strictly similar. BCAA clearances obtained by VVHF we re similar to ultrafiltration rates (respectively, 0.78+/-0.14 and 1.7 9+/-0.28 ml/min at high and low Q(b); p<0.05). The alpha-ketoisocaproa te clearances obtained by WHF were 0.39+/-0.17 and 0.92+/-0.43 ml/min at low and high Q(b) (not significantly different). Whatever the Q(d) value, the VVHDF procedures always allowed higher BCAA and alpha-ketoi socaproate clearances as compared with the corresponding VVHF period w ith similar Q(b). BCAA clearances obtained by VVHDF with a 0.5 L/h dia lysate flow were 4.1+/-0.5 and 5.4+/-0.5 mL/min at low and high Q(b), respectively. The concurrent alpha-ketoisocaproate clearances were 2.5 +/-0.8 and 2.9+/-1.0 ml/min.