Early saphenous vein graft (SVG) occlusion remains one of the most significant limitations of coronary artery bypass grafting (CABG), affecting up to 20% of patients within the first postoperative year. In an effort to address this problem, ticagrelor based dual antiplatelet therapy (DAPT) combined with aspirin has been shown to significantly lower graft failure rates compared with standard aspirin monotherapy. This greater antithrombotic effect, however, comes with a clear trade-off: a clinically meaningful rise in bleeding risk.
From a pathophysiological standpoint, the thrombotic risk affecting the vein graft is not evenly spread over time: platelet activation and endothelial injury peak during the first postoperative months and then gradually settle. This time course implies that the greatest benefit from DAPT is concentrated in the early postoperative period. A practical question therefore follows for everyday clinical practice: is a shorter course of DAPT enough to protect the graft while sparing the patient unnecessary exposure to bleeding risk?
The TOP-CABG trial (Timing of Platelet Inhibition after Coronary Artery Bypass Grafting) was designed to address exactly this question. It is a multicentre, non-inferiority, double blind, placebo controlled, randomised trial with blinded outcome assessment, conducted across thirteen Chinese hospitals between February 2023 and July 2024. The study enrolled 2300 patients aged 18 to 80 years who underwent elective coronary artery bypass grafting with at least one saphenous vein graft. Patients were excluded if they required concomitant valve or aortic surgery, had single vessel coronary disease, needed additional antiplatelet agents, or had contraindications to ticagrelor or aspirin. A total of 2290 patients were randomised 1:1 on postoperative day five to receive either ticagrelor 90 mg every 12 hours plus aspirin 100 mg daily for 12 months, or the same regimen for the first three months only, followed by placebo plus aspirin for the remaining nine months. The trial had two primary endpoints: the one-year rate of vein graft occlusion (non-inferiority analysis) and the incidence of clinically relevant bleeding (BARC — Bleeding Academic Research Consortium — type 2, 3, or 5) during the first year (superiority analysis). Secondary endpoints included major adverse cardiovascular events (MACCE), SVG failure, and stenosis or occlusion of venous or arterial grafts.
Of the 2290 patients included in the intention-to-treat analysis, 2070 were evaluated, accounting for a total of 5125 vein grafts. At one year, vein graft occlusion occurred in 10.8% of grafts in the three month group versus 11.2% in the 12 month group (p=.008 for non-inferiority). BARC type 2, 3, or 5 bleeding over a median follow-up of 368 days was less frequent with the three month regimen than with the 12 month regimen (8.3% versus 13.2%; p<.001), corresponding to a number needed to treat of 21 to prevent one bleeding event. MACCE rates were similar between the two arms (2.3% versus 2.7%). The authors conclude that a three month DAPT strategy was non-inferior to 12 months for vein graft occlusion and was superior in lowering bleeding risk.
COMMENTARY:
The common practice of extrapolating treatment regimens from interventional cardiology has repeatedly generated debate, at times leading to clinical overexposure without a proportional therapeutic gain. The TOP-CABG trial provides robust evidence on a contested aspect of medical management in this population, an area where clinicians had previously relied on underpowered substudies of PLATO, together with POPular CABG and DACAB.
One design feature likely to have shaped the results is the timing of randomisation on postoperative day five, after confirming tolerance to dual antiplatelet therapy, which effectively excluded patients prone to early postoperative bleeding. Combined with the fact that most participants had a low to moderate bleeding risk and underwent elective surgery, the TOP-CABG cohort is essentially a population pre-selected for good early tolerance, a feature that probably contributes to the favourable safety profile observed and limits how far the findings can be extended to patients at higher early bleeding risk. It is also worth noting that roughly 80% of participants were enrolled at a single centre, which calls for caution when applying these results to settings with different perioperative management practices. Finally, the conclusions are specific to ticagrelor and cannot be directly generalised to other antiplatelet agents.
This trial arrives at a time when the overall trend is moving toward reducing dual antiplatelet exposure after coronary surgery, whether by shortening its duration or lowering its intensity (as explored in the TACSI trial). Both approaches point in the same direction: in well selected patients, antiplatelet exposure can be reduced without sacrificing ischaemic protection, while gaining a safer bleeding profile. What remains to be defined is whether, in specific subgroups (severe renal disease, atrial fibrillation requiring anticoagulation, higher thrombotic risk, or more complex anatomy) extending DAPT beyond three months is truly worthwhile; results from ongoing trials such as ODIN are awaited to further refine the optimal strategy.
Overall, this study offers a solid basis for individualising the duration of dual antiplatelet therapy after coronary revascularisation: in patients who tolerate the initial regimen well and do not present a particularly unfavourable ischaemic profile, three months of ticagrelor plus aspirin appear sufficient, with a clear benefit in terms of bleeding.
REFERENCE:
Yuan X, Li J, Lei L, Zhang L, Chen K, Chu Q, et al. Efficacy of dual antiplatelet therapy for three months versus 12 months after coronary artery bypass grafting: multicentre, double blinded, randomised controlled trial. BMJ. 2026;393:e088939. doi:10.1136/bmj-2025-088939
