Adverse events in patients taking apixaban or rivaroxaban who have undergone bariatric surgery: a retrospective case series.

Clinical trials comparing direct oral anticoagulants (DOAC) to warfarin excluded patients with a history of bariatric surgery. The anatomic changes from bariatric procedures have several effects on drug absorption which can have serious consequences for these patients. We sought to describe real-world use of DOACs among adults that had a history of bariatric surgery or underwent a bariatric surgery while receiving a DOAC. We conducted a retrospective case series of adult patients, at a large academic medical center, who initiated any DOAC in 2016 thru 2019 and had a history of bariatric surgery or underwent a bariatric surgery while receiving a DOAC. Thrombotic and bleeding events were described using summary statistics and bleeding severity was described using the International Society on Thrombosis and Haemostasis criteria. Twenty-eight patients met the inclusion criteria of having bariatric surgery (Roux-en-Y gastric bypass, sleeve gastrectomy or gastric band) and receiving a DOAC. Twenty (71.4%) were prescribed apixaban and eight (28.6%) were prescribed rivaroxaban. Seven patients (25%) experienced at least one clinically relevant non-major bleeding event, including one patient (3.6%) that had a major bleeding event. Two patients (7.1%) had a thromboembolic event. Coagulation laboratory studies were infrequently performed at the time of the bleeding or clotting events. Among patients with a history of bariatric surgery, use of DOACs were commonly associated with clinically relevant non-major bleeding events and less commonly associated with major bleeding and thromboembolic events. Larger studies may offer further insight into the overall safety and efficacy of DOAC therapy in patients that have undergone bariatric surgery. The specific role of coagulation laboratory studies warrants further evaluation.