Coronary artery bypass grafting (CABG) is considered as a more complete means of revascularization than percutaneous coronary intervention (PCI). However, acute coronary syndrome (ACS) can still occur after CABG. The culprit vessel can be the graft vessel or the native vessel. Many questions remain unanswered in the Chinese literature regarding this topic: what are the short- and long-term pathological changes that induce ACS? Is there any difference between arterial and venous grafts with respect to the frequency of restenosis? Are there any patts of ACS-related vessels in different periods after CABG? We aim to answer these fundamental questions by analyzing coronary angiographies of patients with recurrent ACS following CABG and provide evidence for reducing post-CABG restenosis.