Atherosclerosis develops unevenly across the vascular tree, yet the molecular basis for this regional susceptibility remains poorly defined. The left internal mammary artery (LIMA), the most durable conduit for coronary artery bypass (CABG) surgery, is uniquely resistant to atherosclerosis in humans; however, it has never been isolated or studied in mouse models, limiting mechanistic insight into atheroprotective pathways. Here, we establish the first method to identify and isolate the murine...