Incidence and size of lateral costal artery in 103 patients

Background: The internal mammary artery is used widely as a conduit for coronary artery bypass grafting. Most practicing cardiac surgeons are unaware of an aberrant side branch, the lateral costal artery (LCA), that arises proximally. Unligated, this side branch has been held responsible for early recurrence of angina in a small number of patients in the literature. In this study we identified the incidence and length of the LCA. Methods: We studied 103 patients who had coronary artery bypass grafting with bilateral internal mammary arteries. The presence or absence of an LCA was noted, and a record was made of the number of intercostal spaces traversed. Results: Thirty-one of 103 patients had an LCA on one or the other side. Twenty-five patients had bilateral LCAs in which length was equal on both sides in 18. Median length was two intercostal spaces (range, one to six). The LCA extended to the fifth space or beyond in 5 patients. Conclusions: The LCA was present in one third of patients who had coronary artery bypass grafting. A few patients had vessels sizable enough to raise concerns about recurrence of angina. It is prudent to exclude the presence of an LCA in all patients who have cardiac operations.