Lateral costal artery: clinical importance of an accessory thoracic artery

Abstract 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.

Lateral-bilateral costal branch (R. costalis lateralis): a clinically relevant anatomical variation / Rama costal lateral bilateral (R. costalis lateralis): una variación anatómica clínicamente relevante

SUMMARY: The lateral costal branch (LCB) is a variation present in 15-30 % of the population. This blood vessel runs parallel and laterally to the internal thoracic artery from which it originates. Knowledge about the LCB is relevant for thoracic surgeons. In this study we present the findings from the dissection in a practical teaching exercise of the cadaver of a 62-year-old male. The thoracic contents were accessed by raising the anterolateral thoracic wall, the pulmonary pedicles were dissected and both lungs were removed. We observed bilaterally the trajectory of the LCB at the level of the medial axillary line parallel to the internal thoracic artery. On the right side, the LCB originates from the internal thoracic artery at the level of the first rib and extends to the eighth intercostal space, with a length of 26 cm and a caliber of 1.95 mm, communicating with the anterior and posterior intercostal arteries. The left branch originates from the internal thoracic close to their origin artery and extends until the sixth intercostal space, with a length of 14 cm and a caliber of 1.55 mm. it connects with the anterior and posterior intercostal arteries. On both sides the arteries were accompanied by a pair of satellite veins. The lateral costal arteries form part of the circulation of the thoracic wall, constituting an accessory arterial system with a trajectory parallel to the internal thorax and the aorta. Knowledge of it is relevant for invasive procedures, and myocardial revascularization procedure.

RESUMEN: La rama costal lateral es una variación presente en el 15-30 % de los casos, y sigue paralelo y lateral a la arteria torácica interna, de la cual se origina, siendo su conocimiento relevante para los cirujanos de tórax. Se presenta un hallazgo durante una disección en una actividad práctica docente, en un cadáver de sexo masculino de 62 años. Se accedió al contenido torácico levantando la pared esternocostal, procedimiento que comenzó con disección de la piel y musculatura hasta exponer ambas clavículas, se realizó un corte transversal de éstas en su tercio lateral para posteriormente realizar sección bilateral desde la primera hasta la octava costilla siguiendo la línea axilar anterior. Una vez revertida la pared esternocostal, se seccionaron los pedículos pulmonares, y se retiraron ambos pulmones. Se observó bilateralmente en la pared torácica el trayecto de un paquete vascular a nivel de la línea axilar media paralela a la arteria torácica interna. En el lado derecho se originaba a 2 cm del trayecto de la arteria torácica interna y se extendía hasta el octavo espacio intercostal con una longitud de 26 cm y un calibre de 1,95 mm, estableciendo comunicaciones con las arterias intercostales anteriores y posteriores, agotándose en ellas. La rama izquierda se originaba a 1,5 cm del trayecto iniciado por la arteria torácica interna extendiéndose hasta el sexto espacio intercostal; presentó un calibre de 1,55 mm y una de longitud de 14 cm, estableciendo comunicaciones con las arterias intercostales anteriores y posteriores, agotándose en ellas. En ambos lados las arterias eran acompañadas por un par de venas satélites. Las arterias costales laterales forman parte de la circulación de la pared torácica, constituyendo un sistema arterial accesorio al de la arteria torácica interna y la aorta. Su conocimiento es relevante en procedimientos invasivos, además de tener un alto valor docente y formativo.