Long-term graft patency is the primary goal of coronary artery bypass graft (CABG) surgery. Despite advancements in surgical techniques, a significant proportion of coronary artery bypass grafts experience failure over time. On average, the patency of venous grafts decreases to 81%, 75%, and 50% at 1, 5, and 10 years, respectively. This high failure rate has driven a transition to arterial conduits, such as internal mammary artery (IMA) grafts. Arterial grafts, in comparison, demonstrate significantly better long-term outcomes, with a 10-year patency rate of 85% compared to 50% for venous grafts, and improved survival rates for patients.

Several factors contribute to graft failure, including surgical technique, characteristics of the target native coronary artery (extent of atherosclerosis, severity of stenosis), and patient co-morbidities such as diabetes, hypertension, and dyslipidemia. At a cellular level, graft failure often results from thrombosis, endothelial dysfunction, vasospasm, and oxidative stress. Narrowing of the graft can significantly reduce blood flow to the revascularized area of the heart, adversely affecting outcomes and sometimes necessitating repeat interventions.

CT coronary angiography (CTCA) has emerged as a robust, reliable, and consistent non-invasive alternative for evaluating both native coronary arteries and bypass grafts. CTCA provides accurate information about graft status using a single intravenous injection of iodinated contrast, making it an attractive diagnostic option.

This study aims to evaluate the effects of various factors, particularly the status of native arteries, on bypass graft patency. The findings could provide insights into factors influencing long-term outcomes after CABG and improve clinical decision-making.