Name the five most common direct coronary targets for bypass grafting.

• A. LAD, RCA, LCX, diagonal, obtuse marginal
• B. Ductus arteriosus, Pulmonary artery, RCA, LAD, PDA
• C. LAD, diagonal, obtuse marginal/left circumflex territory, RCA, and PDA or posterior branches of RCA
• D. Aorta, Pulmonary veins, SVC, IVC

Answer: (C)

The question is asking which coronary vessels are most commonly targeted directly with bypass grafts during CABG.

The best answer lists five targets: the left anterior descending artery (LAD), the diagonal branch, the obtuse marginal branch (left circumflex territory), the right coronary artery (RCA), and the posterior circulation known as the PDA or posterior branches of the RCA. The LAD is the most important supply to the front of the heart, so it is almost always grafted. The diagonal branches come off the LAD and are frequently bypassed when they’re diseased. The obtuse marginal branches come from the left circumflex system and supply the lateral/posterior left ventricle, making them common graft targets as well. The RCA provides the inferior/posterior aspects of the heart, and the posterior descending artery (PDA) is a major part of that territory in most people. Because the heart’s dominance varies, the PDA can arise from the RCA or from the LCX, hence the note “PDA or posterior branches of RCA” to cover the common anatomical patterns.

Non-coronary structures like the aorta, pulmonary veins, SVC, or IVC are not targets for coronary bypass, so they don’t fit. While another option lists LAD, RCA, LCX, diagonal, and obtuse marginal, it omits PDA and doesn’t account for dominance variations, making it less complete.