Influence of low-dose colchicine on coronary microcalcification activity in patients with diffuse coronary artery disease undergoing coronary artery bypass grafting: protocol for single-centre randomised open-label blinded-endpoint trial (the COL-CABG trial).

Abstract

Coronary artery bypass grafting (CABG) is the main method to improve myocardial ischaemia in patients with complex coronary artery stenosis. Whereas, patients with diffuse coronary artery disease (DCAD) have a high incidence of perioperative myocardial infarction (PMI) and long-term major adverse cardiovascular and cerebrovascular events (MACCEs) after CABG. The coronary microcalcification activity reflected by sodium [¹⁸F]fluoride (¹⁸F-NaF) uptake has strong predictive value for the adverse events indication after CABG, which is closely related to the coronary immunoinflammatory microenvironment. Low-dose colchicine (0.5 mg/day) was recommended by the 2024 European Society of Cardiology (ESC) guidelines for the management of chronic coronary syndromes, to be administered except statins and standard secondary prevention therapies, for the prevention of MACCEs. The effectiveness of low-dose colchicine is considered to enhance coronary plaque stability and reduce adverse events, but the mechanism is unclear. Therefore, the aim of this trial is to evaluate the effects of low-dose colchicine on coronary microcalcification activity and the incidence of MACCEs in patients with DCAD undergoing CABG. The COL-CABG trial is a single-centre, prospective, randomised, open-label, blinded-endpoint trial conducted at Beijing Anzhen Hospital, Capital Medical University. The study will prospectively enrol 108 DCAD patients with a tissue-to-background ratio (TBR) >3.6 at Beijing Anzhen Hospital from July 2026 to June 2028, and all patients are planned to undergo CABG. The patients will be randomly assigned (1:1) to (1) the colchicine group and (2) the control group. The primary endpoint is defined as the changes in coronary microcalcification activity (ΔTBR=TBR (baseline)-TBR (90 days)) at 90 days after CABG in comparison with pre-CABG. Secondary clinical outcomes include PMI within 7 days after CABG and MACCEs within 90 days after CABG. MACCEs include all-cause death, cardiogenic shock, spontaneous myocardial infarction occurring after postoperative day 7, stroke and repeat coronary revascularisation. These clinical outcomes will be interpreted as exploratory and hypothesis-generating. This study has been approved by the Institutional Review Board of Beijing Anzhen Hospital, Capital Medical University (approval number: 2025202x). Written informed consent will be obtained from all participants. The results will be disseminated through peer-reviewed publications and scientific conference presentations. ChiCTR2500111659.