A study published in the Journal of American Medical Association showed that aspirin plus ticagrelor, an inhibitor of platelet aggregation, increased graft patency approximately 1 year following elective coronary artery bypass grafting (CABG) with saphenous vein grafting to a greater degree than aspirin-only therapy.
In the DACAB trial (Compare the Efficacy of Different Antiplatelet Therapy Strategy After Coronary Artery Bypass Graft Surgery; ClinicalTrials.gov Identifier: NCT02001771), patients indicated for CABG were randomly assigned (1:1:1) to either 90 mg twice-daily ticagrelor plus 100 mg once-daily aspirin (n=168), 90 mg twice-daily ticagrelor (n=166), or 100 mg once-daily aspirin (n=166). Investigators evaluated saphenous vein graft patency approximately 1 year following CABG surgery. In addition, investigators assessed saphenous vein graft patency at 1 week following CABG, time to first major adverse cardiac event (MACE: composite of cardiovascular death, nonfatal myocardial infarction, or nonfatal stroke), freedom from angina at 1 year, and atrial fibrillation incidence within 7 days after CABG.
At 1 year following CABG, the saphenous vein graft patency rates were 88.7%, 82.8%, and 76.5% in the ticagrelor plus aspirin, ticagrelor-only, and aspirin-only groups, respectively. There was a significant difference between the ticagrelor-aspirin vs aspirin-only groups in terms of saphenous vein graft patency rates at 1-year follow-up (12.2%; 95% CI, 5.2%-19.2%; P <.001). However, no statistically significant difference was found between the ticagrelor-only vs aspirin-only groups (6.3%; 95% CI, –1.1% to 13.7%; P =.10). Furthermore, despite the beneficial effect of adding ticagrelor to aspirin in patients undergoing elective CABG, there appears to be no benefit with ticagrelor-only therapy for increasing graft patency in these patients.
In addition, ticagrelor plus aspirin was possibly more effective than aspirin alone in patients with intermediate SYNTAX scores (score: 23-32; difference, 15.14%; 95% CI, 5.78%-24.50%) or high SYNTAX scores (score: ≥33; difference, 17.64%; 95% CI, 3.36%-31.92%) vs those patients with low SYNTAX scores (score: ≤22; difference, −6.17%; 95% CI, −23.64% to 11.29%; P value for interaction, .04).
A total of 5 major bleeding events occurred during follow-up, with 3 occurring in the combination therapy group and 2 occurring in the ticagrelor-only group. The rates of MACE were low in the total cohort (n=16), as were the rates of the other secondary outcomes.
The open-label design as well as the inability to generalize findings to arterial grafts may limit the study findings. In addition, there was a lack of statistical power to identify a significant effect on the secondary outcomes.
The investigators wrote, “The magnitude of the difference between ticagrelor plus aspirin vs aspirin alone (12%) translates into a number needed to treat of 8 to prevent loss of patency of 1 saphenous vein graft over 1 year.”
Zhao Q, Zhu Y, Xu Z, et al. Effect of ticagrelor plus aspirin, ticagrelor alone, or aspirin alone on saphenous vein graft patency 1 year after coronary artery bypass grafting: a randomized clinical trial. JAMA. 2018;319(16):1677-1686.