Type X dual left anterior descending (LAD) artery masquerading as type 1 LAD — a case report

Background Dual left anterior descending (LAD) coronary artery is a rare congenital anomaly. To date, eleven variants of dual LAD have been described with three published reports of type X dual LAD. Here, we describe a new variant of type X dual LAD with a short LAD artery masquerading as type 1 LAD. Case presentation A 42-year hypertensive female presented with recent onset angina with a treadmill test positive for inducible ischemia. Coronary angiography showed a normal right coronary artery (RCA). The left main coronary artery (LMCA) originated from the left sinus of Valsalva (SOV), giving rise to a LAD and the left circumflex artery (LCX). Appearing a normal angiogram with type 1 LAD based on its length, the presence of a large bare area in LAD territory (especially at the apex) and lack of septal branches prompted a search for an additional vessel. Right SOV injection showed a vessel originating separately from RCA, which was confirmed to be a long LAD on selective injection, with a pre-pulmonic course and giving rise to septal branches exclusively before wrapping around the apex. Computed tomography coronary angiography (CTCA) confirmed the pre-pulmonic course of long LAD, defined its entry to the distal interventricular septum to the right of short LAD, and ruled out other coronary artery anomalies. In the absence of a stenotic lesion in the epicardial coronaries, angina in our case was presumed to be due to microvascular dysfunction. She was discharged on beta-blocker therapy for co-existing hypertension and is asymptomatic on follow-up at one year. Conclusions A short LAD artery of type X Dual LAD could be potentially misdiagnosed as type 1 LAD based on its length. However, an active search for a long LAD could properly diagnose the case as a variant of type X dual LAD, which has important clinical implications. Its awareness is critical for cardiologists and cardiac surgeons to correctly interpret the coronary angiogram and plan proper management.