Major Aortopulmonary Collaterals From Coronary Arteries and Dual Left Anterior Descending Artery in an Adult With Tetralogy of Fallot.

Major aortopulmonary collaterals (APCs) are more common with tetralogy of Fallot (TOF) with pulmonary atresia. Collateral arteries, when present, arise most commonly from the descending thoracic aorta, less commonly from the subclavian arteries, and rarely from the abdominal aorta or its branches or from the coronary arteries. Collaterals arising from the coronary arteries can cause myocardial ischemia due to coronary steal phenomenon. They can be addressed either by endovascular interventions like coiling or surgical ligation during the intracardiac repair. Coronary anomalies are seen in 5%-7% of TOF patients. In approximately 4% of TOF patients, the left anterior descending artery (LAD) or an accessory LAD takes origin from the right coronary artery or right coronary sinus and crosses the right ventricular outflow tract in its course toward the left ventricle. Presence of such anomalous coronary anatomy poses certain challenges during intracardiac repair of TOF.