The TOP-CABG (The Timing of Platelet Inhibition After Coronary Artery Bypass Grafting) trial was a multicenter, randomized, double-blind, noninferiority trial conducted across 13 centers in China that evaluated whether shortening the duration of dual antiplatelet therapy (DAPT) after CABG could maintain graft patency while reducing bleeding risk. The investigators demonstrated that a de-escalated regimen—ticagrelor plus aspirin for 3 months followed by aspirin alone—was noninferior to standard 12-month ticagrelor-based DAPT for graft patency and was associated with significantly fewer clinically relevant bleeding events.

The trial enrolled 2,290 patients (mean age ~61.5 years; 79.4% male) undergoing first-time elective CABG with at least one saphenous vein graft (SVG). On postoperative day 5, participants were randomly assigned in a 1:1 fashion to receive either standard DAPT with ticagrelor 90 mg twice daily plus aspirin 100 mg daily for 12 months or a de-escalated regimen of ticagrelor plus aspirin for 3 months followed by aspirin monotherapy for the remaining 9 months. The primary efficacy endpoint was complete SVG occlusion at 12 months, assessed by coronary computed tomography angiography or invasive angiography. The primary safety endpoint was clinically relevant bleeding (Bleeding Academic Research Consortium [BARC] score ≥2). Secondary endpoints included graft failure (SVG occlusion, SVG revascularization, myocardial infarction in the graft territory, or sudden death), ≥70% SVG stenosis, and major adverse cardiac and cerebrovascular events (MACCE).

At 12 months, SVG occlusion occurred in 10.8% of grafts in the de-escalated DAPT arm and in 11.2% in the standard-duration arm (absolute difference -0.31%; p_{noninferiority} = 0.008; prespecified margin 3.5%), meeting the criterion for noninferiority. Clinically relevant bleeding was significantly lower with de-escalation (8.3% vs. 13.2%; hazard ratio, 0.62; 95% confidence interval, 0.48-0.81; p < 0.001). There were no significant between-group differences in the secondary endpoints, including graft failure, graft stenosis, or MACCE.

The strategy evaluated in the TOP-CABG trial addresses a long-standing trade-off between graft patency and bleeding after CABG. Earlier data were mixed: the CASCADE (Clopidogrel After Surgery for Coronary Artery Disease) trial data showed no improvement in SVG patency or intimal hyperplasia with clopidogrel added to aspirin versus aspirin alone; in contrast, the DACAB (Dual Ticagrelor Plus Aspirin Antiplatelet Strategy After Coronary Artery Bypass Grafting) trial data showed that ticagrelor plus aspirin improved 1-year SVG patency versus aspirin alone, ticagrelor monotherapy was not superior, and major bleeding was infrequent (the study was underpowered for bleeding or clinical outcomes). More contemporary trials such as the POPular CABG (Effect of Adding Ticagrelor to Standard Aspirin on Saphenous Vein Graft Patency in Patients Undergoing Coronary Artery Bypass Grafting) and TARGET (Ticagrelor Antiplatelet Therapy to Reduce Graft Events and Thrombosis) trials failed to show additional patency benefit from extending or intensifying P2Y12 inhibition and observed higher bleeding risk.^1,2 A 2024 meta-analysis confirmed that DAPT after CABG reduces mortality, MACCE, and venous graft occlusion but increases major and minor bleeding.³ Within this evidence base, the TOP-CABG trial results demonstrate that time-limited (3-month) ticagrelor-based DAPT can preserve patency while reducing clinically relevant bleeding, offering a pragmatic de-escalation framework for surgical revascularization.

The findings have practical implications for routine surgical revascularization. For patients with chronic coronary disease undergoing elective CABG, 3 months of ticagrelor-based DAPT followed by aspirin monotherapy appears sufficient to cover the early thrombogenic period when platelet-mediated graft occlusion risk is highest. This approach aligns with contemporary trends toward shorter, risk-tailored antithrombotic regimens observed after percutaneous coronary intervention. In patients at elevated bleeding risk or requiring concomitant oral anticoagulation, an abbreviated DAPT course may offer a favorable balance between ischemic protection and safety. Nevertheless, clinical judgment remains critical because patients with acute coronary syndromes (ACS), complex graft anatomy, or incomplete revascularization were excluded from the trial and may warrant longer therapy.

Limitations of this trial included:

• Absence of an aspirin-only control group, preventing direct comparison with monotherapy;
• Exclusion of patients with ACS and those undergoing off-pump or urgent CABG, which limits generalizability to higher-risk populations;
• Limited female enrollment, restricting sex-specific interpretation; and
• A 12-month follow-up period that may not have fully captured late graft attrition.

References

1. Willemsen LM, Janssen PWA, Peper J, et al. Effect of adding ticagrelor to standard aspirin on saphenous vein graft patency in patients undergoing coronary artery bypass grafting (POPular CABG): a randomized, double-blind, placebo-controlled trial. Circulation. 2020;142(19):1799-1807. doi:10.1161/CIRCULATIONAHA.120.050749
2. Kulik A, Abreu AM, Boronat V, Kouchoukos NT, Ruel M. Ticagrelor versus aspirin 2 years after coronary bypass: observational analysis from the TARGET trial. J Card Surg. 2022;37(7):1969-1977. doi:10.1111/jocs.16492
3. Agrawal A, Kumar A, Majid M, et al. Optimal antiplatelet strategy following coronary artery bypass grafting: a meta-analysis. Heart. 2024;110(5):323-330. Published 2024 Feb 12. doi:10.1136/heartjnl-2023-323097