Review: anticoagulation for haemodialysis.

The coagulation cascade is complex but well studied. Dialysis membranes and lines are inherently pro-coagulant and activate both the intrinsic and extrinsic pathways of coagulation, as well as platelets and other circulating cellular elements. To provide safe and effective dialysis, appropriate anticoagulant measures must be applied. Haemodialysis, including anticoagulation, is prescribed by dialysis doctors but delivered by dialysis nurses. The main agents used in clinical practice for anticoagulation during haemodialysis are unfractionated heparin (UF heparin) and low-molecular-weight heparin (LMWH). LMWH has a number of potential advantages, apart from cost. One of the most serious complications of the use of any form of heparin is heparin-induced thrombocytopaenia (HIT) Type II, which occurs more commonly with UF heparin than LMWH. HIT Type II risks severe morbidity and mortality and is challenging to treat successfully in both the acute and chronic phase. In HIT Type II anticoagulation must be delivered without heparin. A wide array of newer anticoagulants are becoming progressively available, each with unique advantages and disadvantages. In maintenance haemodialysis patients with an increased risk of bleeding, a 'no heparin' dialysis may be undertaken, or regional anticoagulation considered. Because this aspect of dialysis is so important to the safe and effective delivery of haemodialysis therapy, dialysis clinicians need to review and update their knowledge of dialysis anticoagulation on a regular basis.