Preoperative warfarin treatment and outcome of coronary artery bypass graft surgery

The aim of this case-control study was to evaluate the outcome of isolated coronary artery bypass grafting (CABG) when using a short (median, 2 days) preoperative pause in home warfarin treatment.

A consecutive series of 162 patients on long-term warfarin treatment (median international normalized ratio at the time of operation, 1.9) who underwent isolated CABG was compared with a matched control group of 162 patients with no oral anticoagulation.

The operative risk of warfarin-treated patients was higher (p=0.001) than in the control patients. The in-hospital mortality was comparable in the warfarin and control groups (3.7% versus 2.5%; p=0.52), and there were no significant differences in the postoperative blood loss (818 versus 758 mL), transfused red blood cells (2.1 versus 1.8 units), or reoperations owing to bleeding (5.6% versus 7.4%) between the groups. The warfarin group received more (p<0.0001) fresh-frozen plasma (1.9 versus 0.5 units), needed longer treatment in the intensive care unit (4.1 versus 2.9 days; p<0.0001), and tended to have an increased risk of postoperative stroke (4.9% versus 1.2%; p=0.10). A CHADS2 score greater than 2, but not the international normalized ratio level, was associated with an increased risk of stroke when adjusted for other important comorbidities. Comparable results were observed also in 107 propensity-matched pairs.

The risk of bleeding complications after isolated CABG is not increased when using a short preoperative pause in warfarin treatment. Better preventive strategies for stroke are needed, especially in patients with a high CHADS2 score.