The Mammary Artery Lifeline: How Collateral Dependency of Hidden Aortic Occlusion Altered Revascularization Strategy

The mammary arteries are commonly used as an arterial conduit during coronary artery bypass grafting (CABG). However, in a small proportion of patients, unrecognized extracardiac vascular pathology may render internal mammary artery harvest catastrophic during CABG.

A 61-year-old man presented with non-ST-segment elevation myocardial infarction and was referred for CABG. Preoperative computed tomography (CT) angiography revealed complete infrarenal aortic occlusion with extensive collateral perfusion of the pelvis and lower limbs, predominantly via the right internal mammary artery, as well as the intercostal, subcostal, and lumbar arteries. CABG was deemed prohibitively high risk owing to risk of catastrophic ischemia. The patient underwent staged percutaneous coronary intervention, with good recovery.

This case underscores the importance of CT imaging in high-risk CABG candidates at risk of peripheral arterial disease, such as those with absent femoral pulses or claudication. Recognition of critical collateral networks prevents inadvertent conduit harvest and life-threatening ischemia.

CT aortogram in selected candidates safeguards conduit selection and can avert catastrophic perioperative compromise. Coronary management should be individualized through multidisciplinary evaluation, as guideline-based strategies may not account for complex anatomical variations.