The effect of bariatric surgery on the direct oral anticoagulant rivaroxaban: the extension study

Background: Thromboembolic disease is a potentially serious complication in bariatric surgery patients. Direct oral anticoagulants (DOAC) have been investigated in orthopedic surgery patients. DOAC data after bariatric surgery are still limited to the early postsurgical period. Whether postsurgical midterm adaptations due to anatomic and physiologic alterations influence drug pharmacology is currently not known.

Objective: The aim of this study was to investigate the influence of weight loss and type of bariatric surgery on midterm postsurgical pharmacokinetic and pharmacodynamic parameters of rivaroxaban.

Setting: University hospital.

Methods: In this monocentric study, bariatric patients received a single oral dose of rivaroxaban (10 mg) 6 to 8 months after sleeve gastrectomy (SG) or Roux-en-Y-gastric bypass (RYGB). Pharmacokinetic and pharmacodynamic parameters were assessed and compared with prebariatric surgery results.

Results: We included 6 RYGB and 6 SG patients. Percent excess weight loss was 71.4% (interquartile range 56.4, 87.9) in the SG group and 76.6% (64.5, 85.7) in the RYGB group. Rivaroxaban mean areas under the curve 6 to 8 months after the bariatric procedure (922.4 µg × h/L, coefficient of variation 43.2) were comparable to those measured preoperatively (952.6 µg × h/L, 16.8). There was no relevant difference between the 2 surgical procedure groups. Rivaroxaban led to a decrease of prothrombin fragments F1+2 over 12 hours after oral intake confirming in vivo efficacy.

Conclusions: Significant weight loss and altered anatomy after RYGB and SG procedures do not appear to affect the pharmacokinetics and pharmacodynamics of prophylactic rivaroxaban. A single dose of Rivaroxaban was well tolerated and considered safe in this trial.