Congenital Absence of the Left Anterior Descending Artery with Compensatory Septal and Diagonal Supply in a 68-Year-Old Patient: A Rare Angiographic Finding

Congenital coronary artery anomalies are uncommon and are most often discovered incidentally during coronary imaging. Among these anomalies, absence or agenesis of the Left Anterior Descending artery (LAD) is exceptionally rare. We report the case of a 68-year-old patient referred for invasive coronary angiography following a positive stress echocardiogram suggestive of inducible ischemia in the anterior territory. Coronary angiography unexpectedly demonstrated the absence of a conventional LAD arising from the left main coronary artery. Instead, a large diagonal branch and a prominent septal artery provided effective perfusion of the anterior wall and interventricular septum. No significant obstructive coronary artery disease was identified. This case illustrates the importance of recognizing rare coronary anatomical variants, avoiding misdiagnosis as chronic LAD occlusion, and considering complementary multimodality imaging for definitive anatomical characterization.