Antithrombin level and circuit thrombosis during hemofiltration after cardiopulmonary bypass

Hemofilter thrombosis occurs frequently during continuous veno-venous hemofiltration in intensive care units. Among coagulation disorders, antithrombin deficiency has been shown to be linked to hemofilter thrombosis. We investigated whether there was an association between antithrombin level activity and hemofilter thrombosis occurrence during early continuous hemofiltration following cardiopulmonary bypass.

Prospective observational study.

Intensive care unit in University Teaching Hospital.

Forty-eight consecutive patients.

Antithrombin level activity was measured just before the start of hemofiltration, and repeated at 24 h intervals for a total of 3 days. Hemofilter thrombosis episodes were recorded at each 24-h interval following antithrombin level activity measurement. Subjects were classified as HT when one or more episodes of hemofilter thrombosis appeared in this period and NHT if none. Morbidity parameters and mortality were recorded. Mean initial antithrombin level activity was low and not different in HT and NHT groups at day 0 (60.6 +/- 20.9% vs. 63.4 +/- 19.9%, P = 0.68). Antithrombin level activity was lower at day 1 (47.2 +/- 12.0% vs. 58.2 +/- 15.2%, P = 0.03) and day 2 (41.2 +/- 15.3% vs. 53.5 +/- 14.1%, P = 0.04) in HT group. However, antithrombin level activity was not shown to be predictive of HT in multivariate analysis. Morbidity and mortality did not differ significantly between the two groups.

Only a weak association was found between antithrombin level activity and HT during early veno-venous hemofiltration post-cardiopulmonary bypass. This result was not confirmed in multivariate analysis.

Renal failure: dialysis and hemofiltration.