Fixed-dose enoxaparin after bariatric surgery: the influence of body weight on peak anti-xa levels

Funda Celik, Alwin D. R. Huitema, Jan H. Hooijberg, Arnold W. J. M. van de Laar, Dees P. M. Brandjes, Victor E. A. Gerdes

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32 Citations (Scopus)

Abstract

There is lack of data on the pharmacodynamics of low-molecular-weight heparins in obese patients. The aims of this study are to investigate the correlation between anti-factor Xa (anti-Xa) levels and body weight with fixed-dose enoxaparin after bariatric surgery and to investigate the percentage of patients that reach the desired prophylactic range for anti-Xa levels. Blood for anti-Xa peak levels measurement was drawn 3-5 h after administration of enoxaparin at the planned visit 8-16 days after surgery. Patients were included in three categories: <110 kg (group 1), 110-150 kg (group 2), and >150 kg (group 3). Fifty-one patients were included (43.9 ± 9.9 years, 75 % women). Mean anti-Xa level was 0.37 ± 0.14 IU/ml. This level was the highest in group 1 (0.47 ± 0.13 IU/ml) and lowest in group 3 (0.23 ± 0.07). No subprophylactic ( <0.2 IU/ml) anti-Xa levels were detected in group 1, whereas this was observed in 38 % in patients in group 3. Supraprophylactic levels (>0.5 IU/ml) were most often present in group 1 (36 %). With multivariable regression analysis, body weight (β -0.720 (95 % confidence interval -.717; -.993), p  < 0.001) was an independent predictor of anti-Xa levels, whereas lean body was not independently associated. This was confirmed in a non-linear mixed effects analysis of the data. Patients with excessive body weight may not be adequately treated with fixed-dose enoxaparin thromboprophylaxis while patients with lower body weight may have an increased bleeding risk. Body weight is a better predictor of anti-Xa levels compared to lean body weight
Original languageEnglish
Pages (from-to)628-634
JournalObesity Surgery
Volume25
Issue number4
DOIs
Publication statusPublished - 2015

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