Clinical consequences of heparin‐free hemodialysis

Abstract

Heparin-free hemodialysis (HF-HD) has been increasingly used in patients at risk for bleeding, especially in the intensive care unit (ICU). Lack of heparin can reduce solute clearances in continuous hemofiltration; the effect on HD is undefined. Failure to recognize an effect of the anticoagulation strategy upon delivered clearance could contribute to the known problem of underdialysis in the ICU. In addition, the consequences of "locking" dialysis catheters with concentrated heparin solutions are also unclear. This study was designed to define the clinically relevant consequences of HF-HD and catheter locking. In part I, we performed 200 HD treatments on inpatients, of which 100 were performed with heparin, and 100 were performed as HF-HD. We calculated prescribed and delivered Kt/V and dialysis efficiency. In part II, a separate group of 14 patients undergoing HF-HD via central venous catheters had measurement of activated partial thromboplastin time (aPTT) during the last hour of dialysis, as well as 15, 60, and 240 min after catheters were locked with 1:5000 heparin. The prescribed Kt/V was 1.74+/-0.31 for standard HD with heparin vs. 1.66+/-0.36 for HF-HD (p=ns). The delivered Kt/V was 1.42+/-0.32 vs. 1.36+/-0.38 (p=ns). Efficiency was 0.82 vs. 0.84 (p=ns). Baseline aPTT was 28+/-5 s, and increased to 126+/-54 s, 15 min after locking (p<0.0001) and to 71+/-50 s, 60 min after locking (p=0.005). By 240 min, the mean aPTT had fallen to 33+/-9 s (p=0.03), although individual values were still as high as 50 s. The HF technique does not compromise delivery of dialysis to inpatients. Increased treatment time is not necessary. Locking catheters with heparin after HF-HD resulted in prolonged unintentional anticoagulation.

Results of the HepZero study comparing heparin-grafted membrane and standard care show that heparin-grafted dialyzer is safe and easy to use for heparin-free dialysis

“…19 Therefore, fluid infusion (flushes or predilution) NH-HD is currently the gold standard of care in patients with high bleeding risk. 3,4 However, this technique does not provide reliable prevention of severe clotting, which occurs in 15-35% of sessions 20,21 and, in addition to blood loss, it may lead to inadequate dialysis because of frequent and/or premature termination of the session.…”

“…2 No-heparin infusion using regular saline flushes is one of the methods of choice. 3,4 Alternatively, regional citrate anticoagulation (RCA) can be used. Both methods are currently recommended by the 2002 European Best Practice Guidelines for hemodialysis.…”

Catheter Management in Hemodialysis Patients

“…In the following year, using interdialytic tPA locks, a significant reduction in both the incidence of blocked lines requiring tPA infusion (P Ͻ 0.03) and the need for surgical replacement (P Ͻ 0.02) was observed. In a separate study, a 2-mg tPA locking solution preserved catheter performance between HD sessions in 10 patients undergoing HD (75). Further evaluation of lytic locking solutions is warranted .…”

Heparin-induced thrombocytopenia in the critical care setting: Diagnosis and management^

“…In fact, heparin-free hemodialysis has been documented to be as effective as hemodialysis with heparin. Furthermore, in critically ill patients it was documented that the use of heparin locks after heparin-free hemodialysis resulted in prolonged unintentional anticoagulation (98). Similarly, heparin-coated catheters should be avoided whenever possible if all efforts to reduce HIT are undertaken (99 -101).…”