SP463
DIFFERENT DIALYISIS TECHNIQUES, SAME ANTICOAGULANT DOSE?

INTRODUCTION: Routine anticoagulation for extracorporeal blood purification procedures is essential to prevent thrombin generation and premature clotting of the circuit. Low Molecular Weigh Heparins (LMWH) are the anticoagulant of choice for hemodialysis in many European countries. The anticoagulant effect (anti-Xa activity) of LMWH in patients with normal renal function is highly correlated with body weight, allowing use of a fixed dose per kilogram body weight. However, in renal failure, dosing has to be reduced.

It has been suggested that reduction in anticoagulation dose is advisable in high-flux hemodialysis (HF-HD) compared to on-line hemodiafiltration (OL-HDF). However, there are no studies comparing LMWH in different hemodialysis techniques.

The aim of this study is to compare anticoagulation effect with the same dose of LMWH in high-flux hemodialysis, OL-HDF and expanded hemodialysis (HDx)

METHODS: This is an open, randomized, prospective study. Each patient received one standardized high-flux dialysis session (4 hours,dialyzer FxCordiax80® , one post-dilution OL-HDF with dialyzer FxCordiax1000® (infusion flow 100mL/min) and expanded hemodialysis with dialyzer Theranova500®. All sessions were performed with blood flux 400mL/min, dialysate flow 500mL/min, temperature 35.5ºC. Ultrafiltration rate was constant.

Same LMWH dose was used (enoxaparin 40mg), administered by arterial port of dialysis circuit.

Anticoagulant efficacy was studied (pre and post Activated partial thromboplastin time - APTT- and anti Xa factor were measured). Time to clotting of vascular access, hemorrhagic and thrombotic events were registered.

RESULTS: 13 patients (12 men) were included. Mean age was 60.1 ± 4.6 years. All patients had a native arterio-venous fistula.

Mean post-dialysis APTT was higher in HF-HD than OL-HDF (30.5±0.7 vs 28.8±0.73, p=0.009) and higher than HDx (30.5±0.7 vs 28.2 ±0.64, p=0.009). No differences between OL-HDF and HDx were found.

Mean post-dialysis AntiXa is higher in HF-HD than OL-HDF (0.26 ±0.02 vs 0.21 ±0.02, p=0.024) and than HDx (0.26 ±0.02 vs 0.22 ±0.01, p=0.05). No differences were found when post dialysis antiXa was compared in OL-HDF and HDx groups.

We found no differences in time to clotting of vascular access: HF-HD 14.2±1.2 minutes, OL-HDF 13.9±1.6 minutes and HDx 17.1±1.6 minutes.

At the end of dialysis session 85% and 72% of the dialyzers in HF-HD and HDx were classified as “clean” whereas 64% of dialyzers in OL-HDF were classified as “medium”. No hemorragic events were recorded.

CONCLUSIONS: 40mg of Enoxaparin given by arterial port achieves good circuit anticoagulation in HF-HD and HDx. However, the same dosis may be insufficient in OL-HDF.