Avoidance of systemic anticoagulation during intermittent haemodialysis with heparin-grafted polyacrilonitrile membrane and citrate-enriched dialysate: a retrospective cohort study

BACKGROUND Since October 2010, the combination of a heparin-grafted polyacrilonitrile (AN69ST) membrane with a 0.80 mmol/L citric acid-containing dialysate is routinely used in our centre for intermittent haemodialysis, without systemic anticoagulation, in critically ill patients with increased bleeding risk. The primary outcome of this retrospective cohort study was to assess the development of circuit clotting during these dialysis procedures. Secondly, we assessed the impact of clotting on treatment duration, the incidence rate of coagulation-induced retransfusion failure and the association of patient and dialysis characteristics with the occurrence of clotting. METHODS Dialysis and patient data on consecutive intermittent haemodialysis procedures, performed at the Intensive Care Unit of Universitair Ziekenhuis Brussel between October 2010 and March 2012, were retrospectively reviewed. We used descriptive statistics as well as a random effects logit model with patient identity as a panel variable to assess associations. RESULTS Of a total of 309 treatments combining a heparin-grafted AN69ST membrane and a 0.8 mmol/L citric acid-enriched dialysate in 94 patients, circuit clotting was reported in 17.5% (95% CI 13.2% to 21.7%; N = 54), and in 19% (95% CI 13.6% to 24.4%; N = 40) of sessions with prescribed treatment time ≥ 4 hours (N = 210). Clotting shortened treatment time in 15.2% (95% CI 11.4% to 19.7%; N = 47) of sessions by a median of 55 (IQR 20 to 80) minutes. Complete clotting of the circuit with inability for retransfusion occurred in 4.2% (95% CI 2.2% to 7.0%; N = 13) of sessions. Circuit coagulation was not associated with APACHE II score, patient age, gender, number of treatments, type of vascular access or ultrafiltration rate. CONCLUSION Intermittent haemodialysis without systemic anticoagulation combining a heparin-grafted AN69ST dialyzer with a citrate-enriched dialysate favourably compares as to clotting complications with the published outcomes of anticoagulation-free intermittent haemodialysis strategies using saline flushes, heparin-coated dialyzer in combination with regular dialysate or regional citrate anticoagulation with calcium supplemented dialysate. The incidence of circuit clotting in our cohort appears to be higher than previously reported for regional citrate anticoagulation with a calcium-free dialysate.