Right Internal Thoracic ArteryEdit
The Right Internal Thoracic Artery (RITA) is a principal artery of the chest wall that supplies the diaphragm, intercostal spaces, and overlying tissues. As a branch of the right subclavian artery, it travels along the inner surface of the thoracic cage, just lateral to the sternum, and plays a central role in both normal physiology and operative revascularization. In modern surgery, the RITA is valued as a durable conduit for coronary revascularization, particularly in procedures involving the Coronary artery bypass grafting (CABG) program. Its resilience against atherosclerosis and long-term patency have driven widespread use, often in combination with other arterial conduits such as the Left internal thoracic artery.
Anatomy
Origin and course - The RITA typically arises from the first portion of the Right subclavian artery and descends posterior to the upper portion of the costal cartilages. It runs within the thoracic cavity on the inner surface of the chest wall, maintaining a relatively superficial position just lateral to the sternum before giving off branches to the intercostal spaces. - Along its course, the RITA is accompanied by venous and neural structures and may be accompanied by branches of the pericardiophrenic artery, which parallels the phrenic nerve.
Branches and distribution - The artery supplies the anterior intercostal spaces, contributing perforating branches to the breast and chest wall. Its distal portion divides into terminal branches, most commonly the superior epigastric artery and the musculophrenic artery, which extend into the abdominal wall and diaphragm, respectively. - In addition to these major branches, the RITA gives off several small perforators and anastomoses that help maintain chest wall perfusion.
Anatomic variations - While the typical origin is from the right subclavian artery, anatomical variation can occur in origin, course, and branching pattern. Knowledge of these variations is important for surgeons performing diagonal dissections or planning arterial conduits for CABG.
Clinical significance
Use in coronary revascularization - The RITA is widely used as an arterial conduit in CABG due to its high long-term patency compared with venous grafts. In procedures targeting the left anterior descending artery or other coronary targets, the RITA provides durable perfusion and favorable patency rates over many years. - In practice, surgeons may use the RITA as a standalone conduit or in combination with the Left internal thoracic artery in bilateral internal thoracic artery (BITA) grafting. The choice between pedicled and skeletonized harvesting methods affects chest wall blood supply and sternal healing, especially in higher-risk populations.
Harvesting techniques - Pedicled harvesting preserves more surrounding tissue, potentially supporting chest wall integrity but may reduce conduit length or flexibility. - Skeletonized harvesting isolates the artery with minimal surrounding tissue, which can reduce sternal ischemia risk and facilitate use when bilateral ITA grafting is planned. These techniques are subjects of ongoing evaluation in surgical literature and are discussed in relation to patient risk factors and surgeon preference. - During harvest, care is taken to minimize vasospasm and protect the surrounding structures. Vasodilator strategies, including topical or systemic agents, help maintain graft patency and flow.
Patency, outcomes, and comparisons - Relative to alternative grafts such as the saphenous vein, the RITA demonstrates superior long-term patency in many cohorts. Comparative data are most robust when considering arterial grafts, with the LITA often cited as the gold standard for LAD grafting; in appropriate cases, the RITA provides an excellent alternative or adjunct. - Long-term outcomes depend on multiple factors, including target vessel, conduit technique, patient comorbidities, and perioperative management. The RITA’s resistance to atheromatous disease and favorable flow characteristics contribute to its durability.
Complications and considerations - Potential complications include graft spasm, injury to adjacent structures, and, in broader terms, increased surgical time or complexity. Spasm can be mitigated with pharmacologic vasodilators and careful handling during harvesting and implantation. - In the context of multivessel disease or prior sternotomy, decisions about using the RITA must weigh the benefits of arterial patency against risks such as sternal wound issues in susceptible patients. This is a common topic in cardiovascular surgical planning and is addressed in clinical guidelines and discussions within the field.
Relationships with other arterial conduits - The RITA, when used alongside the LITA in BITA configurations, can provide robust, lifelong conduits for multiple coronary targets. The combination of arterial grafts is often favored for improving long-term myocardial perfusion, though it requires careful patient selection and surgical expertise. - The role of the RITA in CABG is part of a broader discussion about arterial versus venous conduits, long-term survival, and quality of life after revascularization. See the literature on arterial graft for broader context.