Title : Internal thoracic artery: Anatomical variations to be considered for bilateral harvesting
Abstract:
The internal thoracic artery (ITA) is a preferred conduit in coronary artery bypass graft (CABG) surgery due to its predictable intrathoracic course, proximity to the heart, and excellent long-term patency. Bilateral ITA (BITA) grafting has demonstrated superior long-term outcomes compared to single ITA use, with increased survival benefits in middle-aged patients extending up to 20 years postoperatively, while up to 10 years in older patients. Given the frequent bilateral use, understanding the variations in surgical anatomy of the ITA is essential.
A study was conducted on 100 adult cadavers to assess anatomical variations. After removing the sternocostal wall and fixing in 10% formalin, detailed dissections were performed. The ITA originated from a common trunk with other subclavian branches in 12% of right and 4% of left cases. The mean length of the right ITA was 20.15 ± 1.22 cm and the left 19.83 ± 1.66 cm. In 28% of cases, BITA terminated at the 6th intercostal space. Three patterns of sternal branch origin were identified: Group I – from a common trunk on both sides (24%), Group II – from a common branch on one side only (54%), and Group III – directly from ITA bilaterally (22%). The phrenic nerve crossed anterior to the ITA on both sides in 52% of cases, posteriorly in 14%, and varied in the remainder.
These anatomical variations, particularly concerning phrenic nerve course, bifurcation level, and sternal blood supply, should be considered during BITA harvesting to minimize risks such as sternal dehiscence and postoperative phrenic nerve palsy.
