Abstract 4367187: Incidental Detection and Coil Embolization of a Calcified Left Main Coronary Aneurysm with Severe Proximal LAD Compression Using Coronary CTA

Introduction: Left main coronary artery (LMCA) aneurysms are exceedingly rare, accounting for only 0.1% of all coronary anomalies. Their detection is often missed on conventional ischemia evaluation. This case illustrates how coronary CT angiography (CTA) can identify complex coronary pathology, including aneurysms and mechanical compression of adjacent vessels. Large LMCA aneurysms pose significant clinical challenges due to their potential for thromboembolism, rupture, and compression of adjacent coronary vessels. Early identification through advanced imaging modalities is crucial for optimal patient outcomes and procedural planning. Description of Case: A 78-year female with a history of hypertension, hyperlipidemia, HIV, and rheumatoid arthritis presented with atypical chest pain. Coronary CTA was performed, revealing an incidental calcified saccular aneurysm, with a size of 33.9 x 33.4 mm, arising from the distal LMCA with intra-aneurysmal calcifications and thrombus (Figure 1). The aneurysm caused mild luminal compression of the proximal LAD (p-LAD). Coronary arteries were non-obstructive. Invasive coronary angiogram was done and the patient underwent coiling embolization to exclude the aneurysm with no periprocedural complications (Figure 2). The patient tolerated the procedure and is planned to have both clinical and non-invasive imaging follow-up. In this patient, CTA enabled prompt diagnosis and guided further intervention. Discussion: This case illustrates coronary CTA's paradigmatic role transcending conventional ischemia-focused diagnostics. Contemporary evidence demonstrates CTA's superior anatomical characterization capabilities, enabling comprehensive assessment of complex coronary pathology including aneurysmal morphology, calcification burden, and spatial relationships with adjacent structures The three-dimensional reconstructive capacity facilitates precise procedural planning by quantifying aneurysm dimensions, determining optimal coil sizing, and predicting potential procedural complications. This case underscores CTA's evolving utility in guiding interventional decision-making for rare coronary anomalies, demonstrating enhanced diagnostic precision and therapeutic stratification beyond traditional functional assessment paradigms.