Background: Coronary artery anomalies are still main problems in tetralogy of Fallot for surgical repair.Left anterior descending artery arising from right coronary artery and crossing the right ventricule
outflow tract is a common coronary artery anomaly associated with tetralogy of Fallot.Case Report: A 16-year-old girl to whom left modified Blalock-Taussig shunt operation was performed when she was four years old was addmitted to our clinic for repair of tetralogy of Fallot with symptoms of cyanosis, quickly fatigue. Total correction could not be carried out in her young childhood period because of origin and pathway anomaly of left anterior descending coronary artery.Corrective operation was done with an unusual technique. In this technique, abnormal left anterior descending artery was dissected and freed and the patch was placed beneath the abnormal coronary artery.Conclusions: In these conditions, an alternative to use of current techniques, abnormal left anterior descending artery may be dissected and freed and the patch could be placed beneath the abnormal coronary artery. Corrective operations of tetralogy of Fallot may be delayed for use of this technique so that increase of the diameter and the length of the artery makes the dissection easy and safe and adequate area remains for patch placement beneath the abnormal coronary artery.

Keywords: Tetrology of Fallot, Coronary Artery Anomalies, patching beneath LAD, Right Ventricle Outflow