Assessment of the Heparin-Binding AN69 ST Hemodialysis Membrane: II. Clinical Studies without Heparin Administration

Abstract

Binding polyanionic unfractionated heparin over the modified AN69 polyacrylonitrile membrane, the surface electronegativity of which has been neutralized by polyethyleneimine (AN69-ST), renders the membrane more hemocompatible. This property was tested in two groups of long-term hemodialysis patients. Results were rated as massive or partial clotting of a dialyzer at the end of the session. Group I patients were included in a prospective, cross-over study comparing standard dialysis with hemodialysis without systemic administration of unfractionated heparin (n = 12, 123 sessions). In all instances, priming was made with 2 I saline containing 5,000 IU/l heparin. Only patchy or partial clotting was observed in 11% and 39% of the sessions with standard and heparin-free administration, respectively. Group II patients were included in an open, observational pilot study testing the effects of the heparin-coated membrane, without systemic administration of heparin, in patients at high risk of bleeding (n = 68, 331 sessions). Massive clotting was observed in six sessions only (less than 2%) and normal or slightly patchy dialyzers were found in 88% of the sessions. It is concluded that the dialysis AN69 ST membrane, after adequate priming at bedside, can be used without systemic administration of heparin for hemodialysis in patients at high risk of bleeding.

Comparison of Two Dialysers (AN69ST vs. FX100) for Heparin-Free Dialysis in Patients with Oral Anticoagulation

“…A complete occlusion of the extracorporeal system was seen in only 1.5% of 66 treatment sessions [7] and in 2% of 331 sessions in patients at high risk of bleeding and without additional heparinization during dialysis [9] . In these studies, however, patients were not treated with oral anticoagulants and coagulation disorders were exclusion criteria.…”

Surface modification of polysulfone based hemodialysis membranes with layer by layer self assembly of polyethyleneimine/alginate-heparin: a simple polyelectrolyte blend approach for heparin immobilization

“…Zhu et al [6], Jiang et al [7] and Huang et al [8,9] also improved blood compatibilities of the poly(vinylidene fluoride), polyethylene (PE) and PSF membranes by covalent attachment of heparin [6][7][8][9]. In vivo tests carried out with commercial hemodialysis membranes, AN69 ST, HEMOPHAN and EVODIAL showed that it is possible to reduce systemic administration of heparin through its immobilization on these membranes [10][11][12][13][14][15]. On the other hand, one clinical study reported that heparin coated AN69 ST membrane does not reduce clotting during hemodialysis when compared to a conventional PSF filter [16].…”

“…The most commonly used approach is to mimic endothelial cell layer by heparin immobilization. The beneficiary effect of heparin coatings on the membranes has been reported by many authors both in vitro [1][2][3][4][5][6][7][8][9] and in vivo [10][11][12][13][14][15]. For example, Cheung et al [1] observed that complement activation induced by hemodialysis can be modulated with heparin immobilized cellulose acetate membrane.…”

“…On the other hand, one clinical study reported that heparin coated AN69 ST membrane does not reduce clotting during hemodialysis when compared to a conventional PSF filter [16]. In most of these studies, heparin was covalently attached to the surfaces, on the other hand, ionic binding was also used for immobilization [10,[12][13][14]16]. Recently, the layer by layer self-assembly (LBL) technique has emerged as a versatile, gentle and easy surface modification method for immobilization of functional molecules.…”

Comparison of the AN69ST Membrane versus Citrate-Enriched Dialysate on Clotting Events during Hemodialysis without Systemic Anticoagulation

“…The heparin grafting is stable and does not get released in the blood. Hence, a local anticoagulation effect with a reduced requirement for or even the elimination of systemic anticoagulation may be possible [8]. …”