This study is a prospective, randomized, placebo-controlled, double-blind, multicenter clinical study to test the research hypothesis that low-dose colchicine (0.5 mg/d) can delay the progression of AAA.~The study will enroll patients with infrarenal abdominal aortic aneurysms with a maximum diameter of 30-50 mm and no indication for surgical or endovascular treatment. All patients will receive the best standard medical treatment. Before randomization, all patients will undergo a 1-month lead-in period, during which open-label colchicine 0.5 mg/d will be administered. If there is colchicine intolerance, they will not be randomized.~The study center performed computer-generated block randomization (block size 8). Randomization method and block size will not unblinded until all data analyses are completed. Enrolled patients will randomly assigned to each hospital in a 1:1 ratio by the randomization center through sequentially coded, sealed, light-tight envelopes, to colchicine and placebo groups.~After randomization, patients will receive low-dose colchicine (0.5 mg/d) or placebo, respectively, and will be followed up for 24 months. We will evulate whether low-dose colchicine can delay the progression of AAA by assessing the change in maximum aneurysm diameter by CTA. At the same time, its effects on abdominal aortic aneurysm-related and cardiovascular-related clinical events will be observed.
COIN trial is a a prospective, randomized, placebo-controlled, double-blind, multicenter clinical study. Approximately 230 patients with small abdominal aortic aneurysms (AAA) will be randomly allocated to low-dose colchicine group or placebo group. All study patients will be followed up in the outpatient clinic every 3 months and undergo CTA scans after 24 months from randomization. The primary objective is to test the hypothesis that low dose colchicine can inhibit the progression of AAA diameter. The secondary objective is to test the hypothesis that low dose colchicine can inhibit the progression of AAA volume, reduce the incidence of clinical outcomes associated with AAA, reduce the incidence of major adverse cardiovascular events and all-cause mortality.