We read the systematic review by Nocerino et al discussing the effect of postoperative dual antiplatelet therapy (DAPT) on graft patency after coronary artery bypass grafting (CABG). We had earlier presented a pooled analysis of 11 studies (both observational and randomized controlled trials) evaluating the benefit of DAPT after CABG.

We have also presented results specifically in patients undergoing off-pump CABG (OPCABG). A recent study has presented an ad hoc analysis of the Randomized On/Off Bypass (ROOBY) trial. The ROOBY study is a randomized controlled trial comparing on- and OPCABG. Although they conclude that DAPT does not affect graft patency in the overall cohort, they found improvement in graft patency in multivariate analysis in patients treated with DAPT who underwent OPCABG (p = 0.014). We conducted an updated meta-analysis of the 3 published randomized controlled trials incorporating only patients who underwent OPCABG. This demonstrated the significant benefit of DAPT (risk ratio for graft occlusion with DAPT 0.50, 95% confidence interval 0.42 to 0.60, p <0.01) in reducing vein graft occlusion. DAPT was also beneficial in reducing postoperative cardiac events (risk ratio 0.29, 95% confidence interval 0.11 to 0.72, p = 0.008) and perioperative myocardial infarction (p = 0.02).

There is a wide variability in the level of anticoagulation targeted during OPCABG. A recent review demonstrated that many preferred partial heparin with or without protamine reversal. Although this method would reduce postoperative bleeding, it would likely create a more prothrombotic environment at the anastomosis, predisposing to platelet accumulation. Intracoronary shunts used during surgery may also create microvascular trauma subsequently leading to an increased tendency for platelet accumulation on the intima. These may be some reasons for the beneficial effect of DAPT in OPCABG.

We believe that DAPT is not without a small but finite risk of bleeding. Rather than adopting a uniform strategy, it is important to tailor this therapy to the individual patient. The use of DAPT with conventional CABG clearly presents conflicting results regarding vein graft patency; however, whenever possible, its use in patients undergoing OPCABG is to be recommended.