Ann Thorac Surg 2002;73:971-973
© 2002 The Society of Thoracic Surgeons
Case report
Ruptured right coronary artery aneurysm presenting as a myocardial mass
Luis D. Berrizbeitia, MD*a,
Louis E. Samuels, MDa
a Department of Cardiothoracic Surgery, Hahnemann University Hospital, MCP—Hahnemann University School of Medicine, Philadelphia, Pennsylvania, USA
Accepted for publication July 20, 2001.
* Address reprint requests to Dr Berrizbeitia, Division of Cardiothoracic Surgery, Graduate Hospital, Pepper Pavilion, Suite 1100, 1800 Lombard St, Philadelphia, PA 19146, USA
e-mail: ldberriz{at}ctsx.net
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Abstract
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Rupture of a coronary artery aneurysm may result in a contained hematoma and an intramyocardial mass. We present a case of a contained coronary artery aneurysm rupture presenting as a mass in the right ventricle. The mass was suspected in a preoperative transthoracic echocardiogram and identified at the time of elective coronary artery bypass surgery. We discuss the pathophysiology, clinical presentation, diagnostic features, and management of this uncommon clinical presentation.
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Introduction
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Rupture of a coronary artery aneurysm usually is a catastrophic event that often leads to sudden death, myocardial infarction, or congestive heart failure. Blood dissects the planes of the ventricular spiral muscles, ruptures into the cardiac chambers, causes wall motion abnormalities, and may cause ischemia by compression of adjacent coronary vessels [1]. If the blood is contained within the myocardial muscle layers, the result may be a contained hematoma and an intramyocardial mass. We present a case of contained coronary artery aneurysm rupture presenting as a mass in the right ventricle. The mass was suspected in a preoperative transesophageal echocardiogram and identified at the time of elective coronary artery bypass surgery. We discuss the pathophysiology, clinical presentation, and diagnostic features of this uncommon clinical entity.
A 57-year-old man presented to the hospital with coronary artery disease associated with congestive heart failure. Previous coronary arteriography had revealed severe three-vessel coronary artery disease that was treated with angioplasty. Afterwards, the patient continued to have intermittent episodes of chest pain, with progressive fatigue and shortness of breath. Cardiac catheterization revealed proximal occlusions to the left anterior descending and circumflex branches of the left main coronary artery, plus multiple proximal occlusions and areas of aneurysmal dilatation in the right coronary artery (RCA); the RCA became totally occluded as it entered the right atrioventricular groove (Fig 1).
Left ventricular ejection fraction was 18%. Echocardiography confirmed depression of ventricular contractile function and revealed mild mitral and trace tricuspid regurgitation. A round, echogenic area in the proximal right ventricle adjacent to the anterior leaflet of the tricuspid valve was noted (Fig 2).
At surgery, there was scarring in the inferior wall and anterior walls of the left ventricle, and an area of firm induration in the proximal right ventricle that measured about 5 cm in diameter and extended from the right atrioventricular groove to the acute margin of the heart. The myocardium overlying the mass appeared normal. Under cardioplegic arrest, the left internal mammary artery was anastomosed to the left anterior descending, and saphenous vein conduits to the first diagonal and second obtuse marginal branches. The muscle overlying the mass was incised and a well-organized thrombus was removed. The remaining cavity measured approximately 5 x 4 x 3 cm and connected directly to the proximal segment of the right coronary artery that bled briskly. The orifice connecting the proximal end of the RCA with the cavity was oversewn and the cavity obliterated with interrupted sutures. The patient was weaned from cardiopulmonary bypass without difficulty. Inotropes were administered for 24 hours after surgery. Recovery was uneventful. The pathology report revealed organized thrombus.
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Fig 1. Selective right coronary arteriogram showing aneurysmal dilatation of the proximal segment of the vessel (arrow) and complete distal occlusion. (AM1 = first acute marginal branch; AM2 = second acute marginal branch.)
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Fig 2. Transesophageal echocardiogram in the horizontal plane showing a mass (arrow) in the lateral aspect of the atrioventricular groove. (AN = right coronary artery aneurysm; RA = right atrium; RV = right ventricle.)
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Comment
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Spontaneous rupture of a coronary artery aneurysm is usually a lethal event. Blood dissects around myocardial layers and ruptures internally into the ventricular or atrial chambers, or externally into the pericardial cavity. Either mechanism causes rapid deterioration of contractile function and death by tamponade or ventricular failure. Diagnosis is made postmortem in the majority of cases for which the incidence of coronary artery aneurysm rupture is unknown. In the setting of a contained rupture, the resulting thrombus is confined to a discrete area of the ventricular wall and may cause myocardial ischemia by compression of adjacent coronary vessels [2]. Management consists of excision of the mass, obliteration of the cavity with ligation of the afferent vessel, repair of the cardiac chambers, and restoration of the coronary blood supply with arterial or venous conduits. Rupture into ventricular and atrial chambers are repaired with patches or by direct suture [1].
Coronary artery aneurysm is defined as a dilatation that exceeds the diameter of normal adjacent coronary artery segments, or the diameter of the patient’s largest coronary vessel, by 1.5 times [3]. The pathogenesis involves destruction of the vessel media, thinning of the arterial wall, increased wall stress, and progressive dilatation of the segment of coronary artery. The most common cause is atherosclerotic coronary artery disease, which accounts for 50% to 90% of the cases. The remaining cases are caused by inflammatory processes that affect the arterial wall directly, typically, mucocutaneous lymph node syndrome (Kawasaki’s disease), Takayasu’s disease, polyarteritis nodosa, systemic lupus, connective tissue disorders (Marfan’s, Ehlers-Danlos), septic emboli, syphilis, and Lyme borreliosis. Less common causes include cardiac lymphoma, congenital coronary artery aneurysms, and trauma to the coronary arteries during angioplasty. The current formulation of the response-to-injury hypothesis of atherosclerosis blurs the distinction between atherosclerotic and inflammatory etiologies. This formulation focuses on endothelial dysfunction rather than endothelial denudation as the first step of an inflammatory process that eventually causes atherosclerosis. Possible causes of endothelial dysfunction include elevated low-density lipoproteins, free radicals damage, hypertension, diabetes, elevated plasma homocysteine concentrations, and infectious microorganisms such as herpes viruses and Chlamydia pneumoniae [4]. In this context, a coronary artery aneurysm is an advanced stage of an inflammatory process that starts with endothelial dysfunction and advances to atherosclerosis and aneurysm formation. Management of coronary aneurysms identified during coronary angiography usually consists of medical therapy with antiplatelet and anticoagulant agents to prevent embolization. The possibility of spontaneous rupture is usually not a consideration. Surgical therapy, consisting of excision of the aneurysm, occlusion of the afferent vessel, and coronary bypass, may result in improved survival [3, 5, 6].
The patient presented in this report experienced a contained rupture of a right coronary artery aneurysm. The case was referred for surgical therapy because of severe coronary artery disease accompanied by ventricular dysfunction. The coronary angiogram revealed aneurysmal disease of the truncus of the right coronary artery and an abrupt cut-off of the vessel with complete distal obstruction. Echocardiography was nondiagnostic. During coronary artery bypass surgery, the hematoma was recognized and excised. Blood supply originated from the proximal RCA and was controlled by direct suture. The marked deterioration of ventricular function may have been explained initially by distal embolization into the distal RCA and subsequent interference of circumferential ventricular shortening by the presence of the mass. The history of previous angioplasty makes direct trauma to the coronary vessel a possible etiology of the aneurysm.
In summary, contained ruptures of coronary artery aneurysms are rare entities that may present as intramyocardial masses. Management consists of evacuation of the hematoma, restoration of the integrity of the atrial and ventricular chambers, and restoration of distal blood supply. Preoperative diagnosis relies on establishing the presence of aneurysmal disease with coronary angiography, and echocardiography which may demonstrate the presence of an intramyocardial mass. Other diagnostic modalities that may be considered are ultrafast computerized tomography or magnetic resonance imaging scanning. Because of the poor prognosis associated with uncontained rupture, primary surgical repair should be considered for all large coronary aneurysms, and for coronary aneurysms in patients undergoing coronary artery bypass surgery.
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References
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Abstract
Introduction
