Coronary Artery Aneurysm

Coronary artery aneurysms (diameter 1.5 times larger than adjacent segments) are uncommon lesions, occurring in about 1.5% of cases and in 5% of patients undergoing angiography. Pseudoaneurysms are segments of dilatation that do not include all layers of the vessel wall, and can be seen following trauma (e.g., cardiac catheterization, surgery) or infection.

The right coronary artery is most commonly involved, followed by the left anterior descending coronary artery (case above) and left circumflex coronary artery.

Coronary artery aneurysms can be caused by atherosclerotic disease (most common in the United States), Kawasaki disease (most common worldwide), Takayasu aortitis, cocaine use, and genetic syndromes (Loeys-Dietz syndrome).

Diagnosis

Coronary angiography, the standard reference technique for diagnosing coronary aneurysms, is invasive and expensive. Further, by only allowing depiction of flow within the lumen it may underestimate the true size of the aneurysm.

Coronary CTA is noninvasive and allows accurate assessment and characterization of the aneurysm, providing information on size, location and the amount of thrombus and calcification.

MRI can also be used with the understanding of its inferior spatial resolution compared to that of CT and its poor detection of mural calcifications.

Complications

Coronary aneurysms may uncommonly present as an acute life-threatening process with angina, myocardial infarction, congestive heart failure, or sudden death. The acute presentation seems to be more common in patients with infectious causes and Kawasaki disease. Hemopericardium is an ominous sign of rupture or impending rupture.

Other complications include thrombosis, emboli, arteriovenous fistula, vasospasm, and rupture.

Between 20% and 40% of untreated patients with Kawasaki disease develop coronary artery abnormalities, with 50% regressing within five years. Giant aneurysms (> 8 mm) are unlikely to resolve, with some leading to stenosis with risk of coronary thrombosis, myocardial infarction, and death.

Overall, the prognosis of coronary artery aneurysms depends on the extent of underlying stenosis.

Management

Patients with Kawasaki disease and coronary artery aneurysms are treated with long term aspirin (can be discontinued if the aneurysms resolve). Depending on the size of the aneurysms, electrocardiography, and echocardiography performed 6–12 monthly is recommended.

Kawasaki patients with aneurysms > 8 mm may require stress testing and coronary angiography to identify stenotic lesions, the addition of warfarin to aspirin therapy (although good data are lacking in this regard), and limitation of strenuous activity. Patients with coronary artery stenoses may require revascularisation.

In adults initial management is with with anticoagulants and antiplatelet agents. Coronary artery bypass surgery is the primary surgical technique for failure of medical management (significant coronary stenosis or angina despite adequate medical treatment).

References

• Brogan PA, Bose A, Burgner D, Shingadia D, Tulloh R, Michie C, Klein N, Booy R, Levin M, Dillon MJ. Kawasaki disease: an evidence based approach to diagnosis, treatment, and proposals for future research. Arch Dis Child. 2002 Apr;86(4):286-90.
• Johnson PT, Fishman EK. CT angiography of coronary artery aneurysms: detection, definition, causes, and treatment. AJR Am J Roentgenol. 2010 Oct;195(4):928-34.
• Murthy PA, Mohammed TL, Read K, Gilkeson RC, White CS. MDCT of coronary artery aneurysms. AJR Am J Roentgenol. 2005 Mar;184(3 Suppl):S19-20.