Lateral Costal Artery: Clinical Importance of an Accessory Thoracic Artery

The lateral costal artery has sometimes been identified as the culprit for the "steal phenomenon" after coronary artery bypass grafting, besides being occasionally used for myocardial revascularization. Its branches make anastomoses with the internal thoracic artery through lateral intercostal arteries. We aim to report, on three cases, the clinical significance of a well-developed lateral costal artery after coronary artery bypass grafting. Two out of three patients who underwent coronary artery bypass graft surgery in our center between June 2010 and August 2017, applied to us with stable angina pectoris, while the third one was diagnosed with acute coronary syndrome after applying to the emergency department. In coronary cineangiography, in all three cases, a well-developed accessory vessel arising from the proximal 2.5 cm segment of the left internal thoracic artery coursed as far as the 6th rib was detected, and it was confirmed to be the lateral costal artery. A stable angina pectoris in two of the patients was thought to be the result of steal phenomenon caused by the well-developed lateral costal artery. In the two cases with stable angina pectoris the lateral costal artery was obliterated via coil embolization. In the other case with the proximal left anterior descending artery stenosis, before percutaneous coronary intervention, the lateral costal artery was obliterated via coil embolization and the occluded subclavian artery was stented. Routine visualization in cineangiography and satisfactory surgical exploration of the left internal thoracic artery could be very helpful to identify any possible accessory branch of the left internal thoracic artery like the lateral costal artery.