According to findings of the POPular CABG trial, the addition of ticagrelor to aspirin after coronary artery bypass graft (CABG) surgery did not reduce the rate of saphenous vein graft (SVG) occlusion. Principal investigator of the trial was Jurriën ten Berg (St Antonius Hospital, Nieuwegein, the Netherlands) and the findings were presented during a late breaking science session at the ESC 2020 Congress (Virtual, 29 August–1 September) by Laura Willemsen (St Antonius Hospital, Nieuwegein, the Netherlands). The findings were simultaneously published in Circulation.
According to Willemsen, POPular CABG sought to test the idea that better platelet inhibition—through the use of ticareglor alongside aspirin post-CABG—could provide better SVG patency. She described ticagrelor as a potent P2Y12 inhibitor, that is fast-acting and has almost no interindividual variability in response profile. Ticagrelor is recommended for the treatment of acute coronary syndromes and ESC guidelines recommend the use of ticagrelor in patients undergoing CABG for ACS.
POPular CABG—an investigator initiated, multicentre, randomised, double-blind, placebo controlled trial—had the hypothesis that the addition of ticagrelor to standard aspirin after CABG will reduce the rate of SVG occlusions, Willemsen explained.
The study’s primary outcome was the SVG occlusion rate at one year after CABG, assessed using coronary computed tomography angiography (CCTA). The secondary endpoint was SVG failure, defined as a composite of SVG occlusions, SVG revascularisations, myocardial infarction in myocardial territory supplied by an SVG, or sudden death. The study also evaluated bleeding events at 30 days and one year after CABG.
A total of 499 patients were included in the trial, 248 randomised to the ticagrelor group and 251 to the placebo group. Endpoint analysis was available for 220 patients in the ticagrelor group, with a total of 484 SVGs included in the primary analysis, and for 223 patients in the placebo group with 470 SVGs.
Baseline and procedural characteristics were comparable between both groups, Willemsen explained, with a mean age of the study population of 68 years. Around 87% of the study population were male. Indication for CABG was acute coronary syndrome in 31% of the population and in 95% of procedures a cardiopulmonary bypass was used.
The SVG occlusion rate in the ticagrelor group was 10.5% (51 of 484 SVGs) versus 9.1% in the placebo group (43 of 470 SVGs), OR 1.29 [95% CI: 0.73 -2.30]; p=0.38. SVG failure occurred in 35 (14.2%) patients in the ticagrelor group versus 29 (11.6%) patients in the placebo group (OR 1.22, [95% CI: 0.72-2.05]).
In conclusion, Willemsen told the ESC audience, “[a reduction of SVG occlusion rates with the addition of ticagrelor could not be established”.
Writing in Circulation, Willemsen and colleagues note that POPular CABG found no discernible effect of adding ticagrelor to aspirin on SVG patency in the ACS subgroup, but added that the result “does not refute the advice of the guidelines to continue ticagrelor in patients undergoing CABG for ACS, as it is possible ticagrelor has antithrombotic and pleitropic benefits that have not relation with SVG patency. ”
Willemsen adds that further research is needed to determine the most appropriate treatment after CABG, “not only to optimise graft patency but also to improve clinical outcomes”.