A patient recently received a DES for unstable angina, then needed an emergent CABG now. How long after the CABG should she continue DAPT?
This is a difficult question to answer. There are few data to guide the surgeon in such a scenario, with most data derived primarily from subgroup analyses of trials designed to evaluate DAPT in ACS patients who then require CABG surgery. However, findings from a recent meta-analysis suggest that higher intensity (prasugrel or ticagrelor) but not lower intensity (clopidogrel) DAPT is associated with lower mortality in ACS patients treated with CABG surgery.1 The addition of a DES adds additional complexity not only with regard to how long the patient should be on DAPT after CABG surgery, but also whether DAPT is truly indicated in the first place and whether it conveys a proven benefit.
Uncertainty in this area is highlighted by a recent survey of Canadian cardiac surgeons.2 Less than half of the surgeons indicated that they routinely use DAPT after CABG surgery in the setting of an ACS. Interestingly, surgeons tended to use DAPT in limited scenarios including a stented vessel without a bypass graft instead of a blanket indication of DAPT for all ACS patients treated with a DES. The thought here may be that many surgeons believe that CABG surgery is protective and resets the clock back to a non-ACS scenario where the role of DAPT is limited. This perception is not in line with current American or European Guidelines that recommend continuation of DAPT post CABG surgery in ACS patients.
I think in the absence of high-level evidence on this subject, surgeons need to balance the risks vs. benefits of postoperative DAPT. I believe that, in the absence of a significant bleeding risk, it is certainly reasonable for the patient at hand to continue DAPT for 1 year after CABG surgery, especially if the DES is in a large vessel that is not bypassed or there are questions about the quality of the target vessel or the conduit used for bypass.
- Verma S, Goodman SG, Mehta SR, et al. Should dual antiplatelet therapy be used in patients following coronary artery bypass surgery? A meta-analysis of randomized controlled trials. BMC Surg. 2015 Oct 14;15:112.
- Yanagawa B, Ruel M, Bonneau C, et al. Dual antiplatelet therapy use by Canadian cardiac surgeons. J Thorac Cardiovasc Surg. 2015 Dec;150(6):1548-54.
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