Left Internal Thoracic ArteryEdit

The left internal thoracic artery (LITA) is a durable and widely used conduit in cardiovascular surgery, renowned for its long-term patency and resistance to atherosclerosis. It originates from the left subclavian artery and travels along the inner chest wall, where it gives off branches to the intercostal spaces and surrounding structures before becoming a preferred graft to the left anterior descending artery in coronary artery bypass grafting. In clinical practice, the LITA is often harvested as a pedicled conduit, though skeletonized harvesting is increasingly employed to optimize chest wall perfusion and reduce potential wound complications. Its exceptional performance has made it a central element of modern revascularization strategies and a benchmark against which other conduits are measured Internal thoracic artery.

The LITA’s anatomical course and physiologic properties contribute to its superiority as a graft. It runs along the inner aspect of the thoracic cage, maintains robust intrinsic tone, and exhibits excellent endothelial function, all of which support superior long-term patency compared with many alternatives. The left ITA commonly branches into the superior epigastric and musculophrenic arteries, with several smaller perforators supplying adjacent tissues. When used as a graft, the LITA is typically anastomosed to the left anterior descending artery, a configuration that has consistently yielded favorable outcomes in terms of survival and reduction of myocardial infarction risk. For discussions of anatomy and operative technique, see Left subclavian artery and Left anterior descending artery.

Anatomy and Variants

Origin and course: The LITA arises from the left subclavian artery (usually the first part) and descends posterior to the upper sternum, running on the inner surface of the thoracic wall. It is commonly harvested with a pedicled tissue sleeve or, in modern practice, sometimes skeletonized to preserve sternal perfusion. See Subclavian artery for broader vascular context.
Terminal branches: The artery gives rise to the superior epigastric and musculophrenic arteries, among other perforating branches that contribute to chest wall perfusion. The conduit is valued for its consistent caliber and resistance to atherosclerotic change.
Variations and considerations: While the typical pattern is well established, minor anatomic variations can occur. Understanding these variations is essential for safe harvesting and effective anastomosis. For a broader view of arterial variability, consult Anatomical variation and Skeletonized harvesting.

Surgical Use and Techniques

Primary indication: The LITA is the conduit of choice for revascularizing the left anterior descending artery in coronary artery bypass grafting (Coronary artery bypass grafting). The combination of high long-term patency and favorable survival data underpins its central role in standard practice.
Harvesting methods: Pedicled harvesting preserves surrounding tissue, including chest wall branches, but skeletonized harvesting—the technique of dissecting the artery with minimal surrounding tissue—can maximize sternal perfusion and lower the risk of sternal wound complications in high-risk populations. See Skeletonized harvesting for technique details.
Conduit configuration: While the LAD is the classic recipient, the LITA can be used in other configurations or as part of composite grafts, depending on coronary anatomy and intraoperative assessment. For alternatives and comparison, see Saphenous vein graft and Radial artery.

Clinical Outcomes and Indications

Patency and durability: LITA to LAD grafts demonstrate superior long-term patency, often cited as 90–95% at 10 years in multiple series, and are associated with reduced rates of recurrent angina and late myocardial infarction compared with many venous conduits. These advantages help justify the priority given to LITA in suitable patients.
Population considerations: The overall benefits are strongest in patients without prohibitive risk factors for wound complications. In populations with higher risk for mediastinal infection (for example, certain diabetes or obesity profiles), surgeons weigh the benefits of LITA patency against potential short-term risks and may adjust harvesting technique or graft strategy accordingly. For broader context on conduit choices, see Saphenous vein graft and Radial artery.

Complications and Risk Management

Common risks: As with any major cardiac procedure, potential complications include wound infection, mediastinitis, bleeding, and graft occlusion. The risk profile can be influenced by patient factors, surgical technique, and perioperative management.
Strategies to mitigate risk: Skeletonized harvesting and meticulous infection control can reduce the chance of sternal wound complications, particularly in high-risk groups. Ongoing evaluation of patient factors and adoption of evidence-based protocols help optimize outcomes.

Controversies and Debates

Bilateral ITA grafting versus single ITA use: Some centers advocate bilateral ITA (BITA) grafting for potential incremental long-term benefits, given the superior patency of ITA conduits. Critics point to a higher risk of mediastinal wound infection and sternal complications, especially in diabetics, obese patients, or those with poor wound healing. The balance often depends on patient risk profiles, surgeon experience, and institutional resources; contemporary practice tends to favor BITA selectively, with techniques such as skeletonization helping to reduce risks.
Conduit choices in diverse populations: While LITA to LAD remains the standard, decisions about using LITA for other targets or employing alternative conduits (radial artery, gastroepiploic artery, or saphenous vein) reflect trade-offs between long-term durability, immediate surgical risk, and resource considerations. Meta-analyses and randomized trials demonstrate that optimized conduit selection and harvesting strategies can improve outcomes without disproportionately increasing perioperative morbidity.
Technical learning curve and access to care: The success of LITA grafting is partly a function of surgical expertise and program experience. In some settings, resource limitations or surgeon training gaps influence decisions, leading to greater reliance on alternative conduits. Advocates of centralized expertise argue that high-volume centers deliver the best balance of durability and safety for LITA use.

History

The modern approach to using the left internal thoracic artery as a superior graft in coronary revascularization began to gain prominence in the late 20th century, with accumulating evidence supporting its superior long-term patency compared with venous conduits. Since the 1980s, LITA-to-LAD grafting has become a benchmark in CABG, shaping guidelines and standard practice in many cardiovascular programs.