Vitamin K antagonist has a higher impact than heparin in preventing circuit clotting in chronic haemodialysis patients.

Abstract

BackgroundIn dialysis sessions, some data suggest that decreasing or even avoiding additional anticoagulation by heparin is possible among patients already treated with oral anticoagulation. However, the required dose of heparin may actually depend on the pre-dialysis international normalized ratio (INR), which varies from one session to another. The aim of our study was to determine the respective role of INR and heparin dosing in the risk of circuit clotting during chronic haemodialysis.Methods From early 2012 to July 2016, we analysed the totality of dialysis sessions performed at Brest University Hospital among haemodialysis patients treated by vitamin K antagonists (VKA). We established a prediction of circuit clotting on the basis of a simplified score obtained by combining INR and heparin dosing.ResultsIn total, 7184 dialysis sessions among chronic haemodialysis patients under VKA were identified, including 233 with clotting events. The mean INR without clotting events was 2.5 versus 1.8 with clotting events (P < 0.001). Frequencies of circuit clotting were different according to INR group (INR <2.0, INR 2.0–3.0, INR >3.0; P < 0.0001). The protective role of VKA was higher than heparin, as shown by discriminant factor analysis (P < 0.0001). Conclusion. Our study established a predictive model of thrombosis risk of dialysis circuits in patients treated by VKA for a given heparin dose and a given INR. This model shows a marginal contribution of heparin to protect against the risk of thrombosis compared with VKA. Moreover, heparin would not appear to be necessary for patients with an INR >2.2.