Ann Thorac Surg 2007;83:668-670
© 2007 The Society of Thoracic Surgeons
Case Reports
Giant Circumflex Coronary Artery Aneurysm Associated With Cystic Medial Necrosis in a Non-Marfan Patient
Koji Takeda, MDa,
Goro Matsumiya, MD, PhDa,*,
Motonobu Nishimura, MD, PhDa,
Hajime Matsue, MDa,
Yasuhiko Tomita, MDb,
Yoshiki Sawa, MD, PhDa
a Division of Cardiovascular Surgery, Department of Surgery, Osaka University Graduate School of Medicine, Osaka, Japan
b Department of Pathology, Osaka University Graduate School of Medicine, Osaka, Japan
Accepted for publication June 23, 2006.
* Address correspondence to Dr Matsumiya, Division of Cardiovascular Surgery, Department of Surgery, Osaka University Graduate School of Medicine, 2-2 Yamadaoka, Suita, Osaka 565-0871, Japan. (Email: matsumg{at}surg1.med.osaka-u.ac.jp).
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Abstract
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Giant coronary artery aneurysm is rare, and its cause and natural history has not been clearly delineated. We present a patient without Marfan syndrome who had a giant coronary artery aneurysm of the circumflex coronary artery. After the surgical resection, the underlying pathology of the aneurysm was thought to be associated with cystic medial necrosis of arterial wall because of its progressive enlargement.
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Introduction
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Coronary artery aneurysms are uncommon lesions that are noted in 0.15% to 4.9% of patients undergoing coronary angiography [1]. Of those, on rare occasions, an aneurysm becomes progressively large enough to be called a "giant coronary artery aneurysm." Several causes have been proposed, including atherosclerosis, congenital malformations, Kawasaki disease, trauma, and infectious arteritis [2]. In this report, we describe a case of non-Marfan patient who had a giant circumflex coronary artery aneurysm associated with cystic medial necrosis as its underlying cause.
A 72-year-old man without a significant coronary risk factor sustained an acute myocardial infarction in the lateral wall of the left ventricle 10 years ago. A coronary angiogram demonstrated occlusion of the proximal circumflex artery. Chest computed tomographic (CT) scan showed a giant coronary artery aneurysm measuring 30-mm in diameter at the posterior atrioventricular groove. During 10 years of follow-up, repeated CT scans demonstrated progressive enlargement of the aneurysm; therefore, he was indicated for surgical intervention.
The physical examination showed no significant findings, including no stigmata of Marfan syndrome. The electrocardiogram showed normal sinus rhythm. A CT scan demonstrated a thrombosed giant aneurysm of the proximal circumflex artery with a 70-mm diameter (Fig 1A) and mild dilatation of the sinus of Valsalva measuring 46-mm in diameter (Fig 1B). An echocardiogram showed akinetic motion of lateral wall of the left ventricle and no valvular insufficiency. A coronary angiogram revealed total occlusion of the proximal circumflex artery and small collateral arteries entering the aneurysmal cavity (Fig 2). The proximal right coronary artery showed ectasia but no significant stenosis.
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Fig 1. Preoperative computed tomographic image demonstrates a giant thrombosed coronary artery aneurysm 70-mm in diameter (*) arising from the circumflex artery (arrow) (A) and mild dilatation of the sinus of Valsalva 46 mm in diameter (B). (LA = left atrium; LV = left ventricle; Ao = aorta.)
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Fig 2. Preoperative coronary angiogram in the right anterior oblique view shows total occlusion of the circumflex artery and small collateral arteries feeding the aneurysm (arrows).
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Results of laboratory investigations included a normal white cell count, negative antinuclear antibodies, and negative serology for syphilis, AIDS, and hepatitis B and C.
At operation, cardiopulmonary bypass was established with ascending aortic and right atrial cannulation. The ascending aorta was of normal size and free of atheromatous change. However, after the insertion of an antegrade cardioplegia catheter, localized dissection of the ascending aorta around cannulation site occurred. We therefore emergently replaced the ascending aorta using a prosthetic graft (Meadex, Hemashield, Boston Scientific, Boston, Mass) under hypothermic circulatory arrest and selective cerebral perfusion.
During the rewarming, the coronary aneurysm was opened, and a large amount of organized thrombus was evacuated. Although the orifice of the proximal and distal coronary artery was not identified, a few small vessels entering the aneurysm were found and cauterized electrically. The aneurysmal wall was resected as much as possible, and the residual sac was obliterated with running sutures. The patient was weaned from cardiopulmonary bypass without difficulty and made an uneventful recovery.
The pathologic assessment of the aneurysmal wall revealed no original structure of the arterial wall due to chronic course of the aneurysm. However, the microscopic finding of the resected ascending aorta was compatible with typical cystic medial necrosis (Fig 3). There was no sign of atherosclerotic change in both specimens.
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Fig 3. Elastica van Gieson stain of the excised ascending aortic wall reveals the patchy mucoid degeneration with splitting of the elastic fibers in the medial layer that was compatible with cystic medial necrosis.
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Comment
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The most common cause of giant coronary artery aneurysm is atherosclerosis. Other reported causes are congenital malformations such as those accompanied with coronary artery fistula, inflammatory (arteritis, Kawasaki disease), iatrogenic (trauma, postangiography), and infectious conditions [2]. In our case, the patient’s history, serology, and pathologic findings did not support any of these diagnoses. The pathologic study demonstrated cystic medial necrosis in the accidentally excised aortic wall that represented a characteristic feature of Marfan syndrome.
Although the aneurysmal wall did not retain the original structure owing to chronic conditions after the related myocardial infarction, we think that the giant aneurysm was caused by vascular changes associated with cystic medial necrosis in our non-Marfan patient. The past examination of the structural change of coronary arteries in Marfan syndrome showed close similarity to its diseased aorta [3]. Actually, there is a report of a Marfan patient in whom cystic medial necrosis of the coronary arterial wall caused the aneurysmal formation of coronary arteries due to neither dissection of coronary arteries nor ostial dilatation after aortic root surgery [4]. This was also reported in a non-Marfan patient with annuloaortic ectasia in combination with coronary artery fistula [5]. In these patients, however, the left main coronary artery was mainly involved in relation to the diseased aorta. Interestingly, in our patient, the aneurysmal change of the circumflex artery was due to cystic medial necrosis.
The natural history and standard treatment of giant coronary artery aneurysms remain unclear because of its rarity [6]. In our patient, we proposed a 10-year natural history of the aneurysm due to cystic medial necrosis that showed slow but progressive enlargement resulting from small collateral arteries feeding the aneurysmal cavity, or it might be related to presumable fragility of the coronary arterial wall. Although the spontaneous rupture of coronary aneurysms is unusual, surgical treatment should be performed as early as possible to avoid further extension and another coronary embolization.
Preoperative differential diagnosis of the precise etiology of coronary artery aneurysms seems difficult. In the present case, mild dilatation of the sinus of Valsalva might imply the existence of the underlying cystic medial necrosis. In the management of patients with coronary aneurysms, special attention should therefore be paid to the underlying cystic medial necrosis as one of the causes. Moreover, careful follow up is mandatory for progressive dilatation and additional dissection of the aortic root including coronary arteries.
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References
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- Syed M, Lesch M. Coronary artery aneurysm: a review Prog Cardiovasc Dis 1997;40:77-84.[Medline]
- Robinson S. Aneurysms of the coronary arteries Am Heart J 1985;109:129-135.[Medline]
- Becker AE, van Mantgem JP. The coronary artery in Marfan’s syndromeA morphologic study. Am J Cardiol 1975;36:315-321.[Medline]
- Onoda K, Tanaka K, Yuasa U, Shimono T, Shimpo H, Yada I. Coronary artery aneurysm in a patient with Marfan syndrome Ann Thorac Surg 2001;72:1374-1377.[Abstract/Free Full Text]
- Kazui T, Washiyama N, Muhammad BA, Yamashita K, Takinami M, Miura K. Surgical treatment of annuloaortic ectasia with coronary aneurysm and fistula Ann Thorac Surg 2001;71:2018-2019.[Abstract/Free Full Text]
- Li D, Wu Q, Sun L, et al. Surgical treatment of giant coronary artery aneurysm J Thorac Cardiovasc Surg 2005;130:817-821.[Abstract/Free Full Text]
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Abstract
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