Direct Oral Anticoagulant Levels at Time of Elective Surgery

Before elective surgery, direct oral anticoagulants (DOACs) are discontinued following a standardized protocol. However, this could result in insufficient lowering of DOAC levels that could increase bleeding risk.

To estimate the proportion of patients with elevated DOAC levels at the time of elective surgery, evaluate factors associated with DOAC levels, and examine associated blood loss.

This cohort study (DOAC Level Prior to Incision [DALI]) assessed adult patients prescribed a DOAC (apixaban, dabigatran, or rivaroxaban) for any indication and at any dose, undergoing an elective procedure requiring DOAC interruption between May 27, 2018, and February 25, 2024, at 2 Dutch hospitals.

Standardized interruption protocol (1 day before moderate- and 2 days before high bleeding-risk procedures) with interruption adjustments for the patient's kidney function.

Blood was drawn immediately before surgery to determine DOAC levels (by liquid chromatography-mass spectrometry). Proportions of preoperative DOAC levels of 30 ng/mL or higher and their 95% CIs were estimated, stratified by DOAC type and surgical bleeding risk. Factors associated with DOAC levels were identified through multivariable linear regression. Surgical blood loss and 30-day postoperative complications were described according to DOAC concentrations.

The study was terminated after including 257 patients (100 receiving apixaban, 100 receiving rivaroxaban, and 57 receiving dabigatran due to the slow inclusion rate of those receiving dabigatran; median [IQR] age, 72 [66-78] years; 173 male [67%]); 212 patients (82%) underwent a high bleeding-risk operation. Preprocedural DOAC levels were 30 ng/mL or higher in 7.6% (95% CI, 4.9%-11.6%) of patients. Dabigatran and rivaroxaban had similar proportions, whereas 13.1% (95% CI, 7.8%-21.2%) of patients treated with apixaban had levels of 30 ng/mL or higher. Treatment with apixaban, decreased kidney function, and a shorter interruption time were associated with higher levels. Surgical blood loss (median [range], 0 [0-4250] mL) was not associated with DOAC levels. Twelve patients (4.7%; 95% CI, 2.7%-8.0%), who all had DOAC levels less than 30 ng/mL, experienced major bleeding.

In this cohort study, most patients following the current protocol had DOAC levels less than 30 ng/mL, although the proportion of patients with elevated levels was higher for apixaban. Preoperative DOAC levels were not associated with blood loss during surgery.