Presence of Factor-VII and -XIII activity in ultrafiltrate during hemofiltration

Bleeding complications during renal replacement therapies can be attributed to coagulation system and platelet function alterations in uremia, and the application of heparin in extracorporeal circulation. Small protein losses during hemofiltration are always described, however the high molecular wei ght of coagulation factors should significantly prevent their removal durin g hemofiltration. To exclude degradation of coagulation factors under condi tions of spontaneous ultrafiltration, the hemofiltrate of 40 patients with acute renal failure (treated with continuous venovenous hemofiltration, CVV H) was sampled from the filtrate line after 1 h from the beginning of treat ment and in 5 patients also after 12 and 24 h. Samples were investigated wi th human factor deficient plasma (VII, X, Xl, XII) from donors with a conge nital deficiency and with human plasma depleted of factor V, VIII, IX, and protein S and C. Factor XIII was detected photometrically. Subsequently the presence of factor- XIII and -VII activity was investigated in plasma and hemofiltrate from 16 patients treated with intermittent hemofiltration befo re (plasma) and after (plasma, hemofiltrate) therapy These patients also su ffered from acute renal failure and needed renal replacement therapies. Qua lify control was carried out with a buffer solution (<1% activity in the as says according to recommended protocols). Results: Facfor-V, -VIII, -IX, -X , -XI, and -XII activity, and protein C and S could not be defected in the hemofiltrate from continuous hemofiltration. Factor-VII and -XIII activity was present in the hemofiltrate (mean activity in CVVH: 1.93% for factor VI I and 6.9% far factor XIII, mean activity in intermittent hemofiltration: < 1% for factor-VII and 7.3 % for factor-XIII). Three were no significant dif ferences (Student's t-test) in plasma activity before and after intermitten t hemofiltration of factor VII (44 vs. 47%, p = 0.39) and factor XIII (44 v s. 52%, p = 0.24). The presence of factor-VII and -XIII activity in the hem ofiltrate cannot influence plasma activities in intermittent hemofiltration . Rapid new synthesis and short half-life should neutralize these effects. Elimination of coagulation factor-XIII activity should be excluded by the n ext generation of highly permeable membranes and on-line hemodiafiltration.