Giant Left Main Coronary Artery Aneurysm and Atherosclerotic Coronary Tree: Additive Value of Coronary CT Angiography Over Conventional Angiography

Giant aneurysms are extremely rare anomalies of the coronary tree. Regarding the site of involvement, the left main coronary artery (LMCA) is the least encountered of all. Coronary angiography is invariably the diagnostic method of choice but infrequently, standard injections might be inadequate to clearly opacify the distal segments. In this particular state, coronary computed tomography angiography (CCTA) offers comprehensive imaging of the entire coronary tree and the contents of the aneurysm (calcification and thrombus). CCTA may also facilitate demonstrating the mass effect of the aneurysm, if it exists.
A 44-year-old patient on routine dialysis treatment was suspected of having significant coronary artery disease due to typical exertional symptoms and abnormal stress test results in the course of evaluation for eligibility for renal transplantation. Coronary angiography was performed, and a giant aneurysm over 4 cm in diameter possibly emerging from the LMCA, was detected. The left anterior descending artery (LAD) could not be opacified in the left coronary injections, and the coronary segments adjacent to the origin of the aneurysm were not visualized either. Therefore, a CCTA was scheduled and it illustrated not only the LAD course but also 2 other intermediate arteries that were not recognized on coronary angiography, nature of the aneurysm, and atherosclerotic burden of the entire coronary tree. The patient was treated with surgery due to proven severe myocardial ischemia and to modify the risk of the upcoming transplantation procedure. The occlusion of the branches originating from the LMCA, sac shrinkage, and bypass grafting were the consecutive steps of the selected method of heart surgery.
Comprehensive imaging of a giant coronary aneurysm is a challenging issue and utilization of different modalities, including CCTA, is essential in the majority of cases. Due to the rarity of the situation, deciding on the necessity of intervention and the method of choice are also controversial. We sought to discuss these equivocal issues in light of the limited knowledge in the existing literature.