There is the association between obesity and type 2 diabetes mellitus (DM) and the impairment of graft patency in post-coronary artery bypass graft operation. The obesity and type 2 DM are the interrelated conditions, which strongly increases the risk of cardiovascular diseases in association with perivascular adipose tissue (PVAT) dysfunction. Additionally, the unique characteristic of PVAT in different anatomical regions may potentially cause the diverse pathological response and graft patency. Therefore, the current projects are focused on the effect of obesity and type 2 DM on the PVAT of saphenous vein grafts, related to the pathological substrates of these vascular wall in the patients, who undergo coronary artery bypass grafting surgery.