Haemodialysis without anticoagulant: haemostasis parameters, fibrinogen kinetic, and dialysis efficiency

Haemodialysis without anticoagulant is an alternative to systemic anticoagulation of patients at high risk of bleeding. However, reports have suggested that heparin-free haemodialysis might results in blood defibrination, and fibrin deposition in dialytic membrane with possible reduction in dialyser efficiency.

Haemostasis parameters, fibrin-fibrinogen kinetic assessed by 125I-fibrinogen (125I-F) turnover and 125I-fibrinogen deposition within the dialyser membranes, and dialytic efficiency were studied in 10 stable chronic uraemic patients. Each patient was dialysed on two consecutive 4-h dialyses, once with each of two dialysis strategies: haemodialysis without anticoagulant and conventional haemodialysis using heparin as anticoagulant.

No significant changes were seen in mean platelet count, plasma fibrinogen, prothrombin time, and antithrombin III during haemodialysis without anticoagulation, and these parameters were not different from those in patients who underwent conventional haemodialysis. Compared with the predialysis values, a shortening of the mean aPTT from an initial mean value was noted (P < 0.05) in haemodialysis without anticoagulation at 60, 120 and 240 min. Fibrin-fibrinogen degradation products remained unchanged during conventional haemodialysis, but were increased after the 30th minute of haemodialysis without anticoagulation (P < 0.05), although all values were in normal range. The biological half-life of 125I-F in uraemic patients before the haemodialysis was 5.02 +/- 0.43 days (control). There was a significant fall in 125I-F half-life during haemodialysis without anticoagulation (2.56 +/- 0.58 days; P < 0.01) but not during conventional haemodialysis (4.77 +/- 0.97, NS). After use each dialyser was dismantled and 125I-F deposition within the membranes (M#5, M#12 and M#19) was measured. During haemodialysis without anticoagulation mean fibrin deposition in M# (28.74 +/- 10.50 x 10(3) counts), M#12 (26.42 +/- 9.06 x 10(3) counts), and M#19 (21.97 +/- 8.33 x 10(3) counts) was greater (P < 0.001) than that during conventional haemodialysis (1.70 +/- 0.92 x 10(3), 1.33 +/- 0.65 x 10(3), and 1.59 +/- 1.03 x 10(3) counts respectively). However, this greater deposition of fibrin on membranes during haemodialysis without anticoagulation did not change dialyser efficiency as assessed (haemodialysis without anticoagulation vs conventional haemodialysis) by change in serum urea (-53.96 +/- 3.38% vs -51.96 +/- 5.20%, NS), serum creatinine (-48.65 +/- 5.99% vs -49.59 +/- 6.65%, NS), serum potassium (-30.06 +/- 4.46% vs -27.64 +/- 2.81%, NS), serum bicarbonate (+25.91 +/- 1.39% vs +24.89 +/- 2.59%, NS) and haematocrit (+3.20 +/- 3.99% vs 2.15 +/- 2.01%, NS). The mean Kt/V was similar for conventional haemodialysis (0.870 +/- 0.074) and haemodialysis without anticoagulation (0.873 +/- 0.107).

In conclusion, although conventional haemostasis parameters remained unchanged during haemodialysis without anticoagulation, some degree of activation of coagulation system occurs, haemodialysis without anticoagulation was associated with greater decline in 125I-F half-life and greater fibrin deposition on dialyser membranes, but with no change in dialyser efficiency.