Half-dose direct oral anticoagulation versus warfarin for atrial fibrillation following cardiac surgery.

Background: Optimal anticoagulation strategies have not been defined for patients with atrial fibrillation following cardiac surgery.

Methods: From a total cohort of 228 patients with pre-existing or new onset atrial fibrillation following coronary artery bypass grafting and/or valve surgery, we compared in-hospital and 30-day outcomes in 119 patients treated with low-dose aspirin and a half-dose direct oral anticoagulant (DOAC) versus 109 treated with low-dose aspirin and warfarin.

Results: DOAC patients were older (73.1±7.0 vs. 68.7±11.4 years, P<0.001) and had a lower incidence of preoperative atrial fibrillation (37 [31.1%] vs. 69 [63.3%], P<0.001). Otherwise, the two cohorts were well matched for baseline demographics, cardiovascular risk factors, comorbidities, prior cardiac history and STS Risk Score. In comparison to Warfarin patients, DOAC patients had a shorter length of post-surgical stay (6 [5-8] vs. 7 [5-10] days, P=0.037). The two cohorts, however, had a similar incidence of stroke, transient ischemic attack, reoperation for bleeding and postoperative blood bank product usage. Follow-up 30-day outcomes did not differ between the two groups with respect to mortality (0 [0.0%] vs. 0 [0.0%], P=1.000) and hospital readmission (16 [13.4%] vs. 14 [12.8%], P=0.893), although two DOAC patients required drainage of sanguineous pericardial effusions.

Conclusions: In comparison to warfarin, half-dose DOAC anticoagulation in patients with atrial fibrillation following cardiac surgery is associated with a shorter postoperative length of stay, without a significant increase in stroke/transient ischemic attack, reoperation for bleeding or postoperative blood product transfusion. Follow-up echocardiography in anticoagulated patients is recommended to rule out significant sanguineous pericardial effusions in the early postoperative period following hospital discharge.