Application Of Anti-Xa Activity Detection In Low-Molecular-weight Heparins Anticoagulation During Hemodialysis

Aim: Effective anticoagulation is essential for hemodialysis to maintain the patency of the extracorporeal circuit(ECC).In recent years,LMWHs have been employed increasingly as anticoagulants during hemodialysis due to its safety,effectiveness and high bioavailability.However,the optimal anticoagulation strategy for dialysis patients using LMWHs as an anticoagulant is unknown.By testing the anti-Xa activity of LMWH,the aim of this study is to ascertain whether accumulation of LMWHs occurs during hemodialysis and to evaluate the practical value of anti-Xa activity in adjusting the dose of LMWHs and predicting the anticoagulant effect during hemodialysis.Methods: Patients with maintenance hemodialysis using low molecular weight heparin in the hemodialysis center of Zhejiang People's Hospital during January-March 2018 were included.A standard hemodialysis session lasted 4 hours.First,we investigated the concentration curve of dalteparin in dialysis participants after injection.In participants(n=20)who received a dalteparin dose of 5000 IU,anti-Xa activity was measured at 0 h,0.5 h,1 h,2 h,3 h and 4 h after the start of hemodialysis,and the peak and trough time points of anti-Xa activity during dialysis were determined.Next,all included participants had anti-Xa activity measures at 0.5 and 4 hours.Extracorporeal circuit(ECC)clotting was evaluated by visual inspection of the hemodialyzer and bubble trap after each hemodialysis session.The same person was tested at three consecutive hemodialysis sessions.Analyses were undertaken using SPSS v24.0 and Graph Pad Prism7.One-way analysis of variance(ANOVA)was done to compare the anti-Xa levels of participants at 0.5 h and 4 h of three consecutive hemodialysis sessions.We used the generalized estimating equation(GEE)model to evaluate the correlation between LMWH dose,anti Xa activity and ECC coagulation results.Results: Overall,90 participants were enrolled and 259 hemodialysis sessions assessed.There was no significant difference in the mean anti-Xa activity at 0.5 and 4 hours for three consecutive sessions,so LMWH accumulation did not occur.The trend of anti-Xa levels in 20 participants receiving dalteparin showed that the Peak anti-Xa activity was recorded 0.5 h after hemodialysis initiation,and the trough anti-Xa levels were recorded at 4 h.There were 69(26.6%)sessions in which ECC clotting was visible.Compared with the group where circuit clotting did not occur,the LMWH dose and anti-Xa activity in the the group where circuit clotting occurred were significantly lower.At 0.5 h,anti-Xa <0.88 IU/mL had significantly higher odds of ECC clotting than that at?0.88 IU/mL.At 4 h,anti-Xa <0.35 IU/mL had significantly higher odds of ECC clotting than that at ?0.35 IU/mL.Conclusions: This study provides evidence that the determination of anti-Xa activity may be beneficial in predicting the anticoagulant effect and guiding dose adjustment of LMWH.Anti-Xa activity of > 0.88IU/ml at 0.5 hour into a HD session and > 0.35IU/ml at the end of a 4 hour session was associated with a lower risk of ECC clotting without risk of bleeding.In addition,there may be no significant LMWH accumulation in subjects receiving LMWH between 2000 and 5000 IU over 3hemodialysis sessions.