What is a potential risk associated with using bilateral internal mammary arteries (BIMA)?

• A. Decreased graft patency
• B. Increased risk of sternal wound complications
• C. No risk differences compared to LIMA
• D. Increased risk of renal failure

Answer: (B)

Using bilateral internal mammary arteries in CABG can increase the risk of sternal wound complications. Removing both arteries from the chest wall reduces the blood supply to the sternum and requires more extensive dissection, which can impair healing and raise the chance of infection or mediastinitis, especially in patients with diabetes, obesity, or other risk factors. This is the main trade-off with BIMA: it can offer better long-term graft patency and survival, but it comes with a higher risk of sternal wound problems. The other options don’t fit as well because BIMA doesn’t inherently cause decreased graft patency (it often improves patency) or renal failure, and there is a real difference in risk compared with using a single internal mammary artery.