Safety of coronary artery bypass surgery during therapeutic oral anticoagulation

Therapeutic (international normalized ratio, INR 2.0-3.5) oral anticoagulation (TOAC) is assumed to increase perioperative bleeding complications and a standard recommendation is to discontinue warfarin before coronary bypass grafting (CABG).

To assess the safety of TOAC we retrospectively analyzed consecutive patients (n=270) with long-term warfarin therapy referred for CABG in two centers where TOAC strategy is employed. The main in-hospital outcomes of interest were death, stroke, acute myocardial infarction, new onset renal failure, resternotomy, and their composite. In the TOAC group of 103 patients CABG was performed during therapeutic oral anticoagulation and in the control group (81 patients) preoperative INR was lowered to a subtherapeutic (≤1.5) level.

The patients in TOAC group were more often operated on an emergency basis (p=0.02) and their EuroSCORE was higher (p=0.02). There were no significant differences in the major outcome events or their composite (17.5 vs. 11.1%, p=0.30) between the groups. Patients in the TOAC group had more postoperative blood loss (941±615 vs. 754±610 ml, p<0.01) and received more fresh frozen plasma (2.8±3.0 vs. 1.3±2.4 units, p<0.001), but transfused red blood cells (2.1±2.8 vs. 2.1±3.4 units) were comparable in the groups. Preoperative clopidogrel (OR 4.8, 95% CI 1.4-16.2, p=0.01) and enoxaparin therapy (OR 2.6, 95% CI 1.1-6.5, p=0.04) were the only significant independent predictors for any major adverse event.

Our study suggests that CABG is a safe procedure during TOAC with no excess bleeding or major complications. Prospective trials are needed to confirm this observation.