DIAGNOSTIC DILEMMA David Reich, MD, and Steven Konstadt, MD, Section Edttors
An Unusual Cardiac Mass Shown By Intraoperative Transesophageal Echocardiography Christopher J. O'Connor, MD, and Robert March, MD A
49-YEAR-OLD man with a history of coronary artery disease (CAD) and three prior myocardial infarctions (MIs) was admitted to an outside hospital with the recent onset of unstable angina. A coronary anglogram demonstrated an 80% mid-left anterior descending artery (LAD) occlusion, a n 80% first diagonal occlusion, a subtotal circumflex occlusion, and moderate right coronary artery (RCA) disease. The left ventriculogram showed regional left ventrlcular dysfunction, and the electrocardiogram demonstrated an old inferior wall MI and new lateral wall ischemia. After an acute MI was ruled out, the patient was treated with intravenous heparin and nitroglycerin and transferred to this institution for surgical revascularization. Anesthetic induction was uneventful and baseline hemodynamic parameters were within normal limits. Routine biplane transesophageal echocardiography (TEE) examma-
tion after induction showed an unusual structure m the four-chamber long-axis view (Fig 1). Color Doppler imaging showed minimal to no flow within this structure. What is this lesion?
From the Departments of Anesthestology and CardtovascularThoracw Surgery, Rush-Presbyterian-St Luke's Medzcal Center, Rush Medical College, Chzcago, IL Address reprint requests to Christopher J O'Connor, MD, RushPresbyterian-St Luke's Medtcal Center, 1653 W Congress Pkwy, Chtcago, IL 60612 Copyright © 1995 by W B. Saunders Company 1053-0770/95/0901-001953 00/0 Key words transesophageal echocardtography, aneurysm, coronary artery, cardiac mass
Fig 1 Transesophageal echocardiogram, transverse plane, showing the four-chamber longaxis view of the heart, The structure in question is outhned by the arrowheads LA, left atrium, RA, right atrium,
Journal of Cardtothoraclc and Vascular Anesthesia, Vol 9, No 1 (February), 1995 pp 103-105
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Fig 2 A photograph of the heart with the chest spread and permardium opened. The aneurysrn involves the orlg,n of the RCA and Is located overlying the aorta and adjacent to the saphenous vein graft to the posterior descending artery (white arrows). The vein graft to the diagonal artery also can be observed (black arrows) An, coronary artery aneurysm, Ao, ascending aorta. DISCUSSION
Dtagnosls. Large Fustform Aneurysm of the Right Coronary Artery After the pericardium was opened, it became apparent that this mass was a large coronary artery aneurysm (Fig 2). The surgeons confirmed that the angiogram had also demonstrated aneurysmal disease revolving the LAD and diagonal and right coronary arteries. The largest aneurysm involved the RCA, and although the aneurysm cavity did fill partially with contrast, flow was sluggish. Because of the diffuse nature of the aneurysmal changes, the aneurysm was left undisturbed and the R C A and diagonal artery were successfully bypassed with vein grafts The minimal flow demonstrated by color Doppler analysis was consistent with the sluggish flow observed at angiography. Pulsed Doppler assessment of the aneurysm might have documented flow that, together with the color Doppler findings, would have identified this as a vascular structure. Also, Fig 1 shows the presence of thrombus within the cavity of the aneurysm, just above the lower right arrowhead. Longitudinal views showed the aneurysm in a location anterior to the ascending aorta and anterosuperaor to the right atrium (Fig 3). The aneurysm actually appears as two distinct masses in this view as the large, ectatic vessel is transected longitudinally Two previous case reports documented coronary aneurysms by TEE, although only monoplane imaging was employed. Quinn et al noted two aneurysms of the right and left coronary arteries m the right and left atrioventricular grooves, respectively. 1 Two-dimensional examinanon showed spontaneous echo contrast, whereas color Doppler
showed no flow, and necropsy confirmed extensive thrombosis of both aneurysm cavities. Tunick et al also detected two large aneurysms of both coronary arteries in a single patient by TEE. 2 The right coronary aneurysm was 2.0 × 2.5 cm and occupied the right atrioventricular groove, whereas the left coronary aneurysm was posterior and to the left of the aortic root. The aneurysm m this patient was also located at the junction of the right atrium and ventricle. Based on these reports, it has been suggested that coronary artery aneurysms be considered in the differential diagnosis of any extracardiac mass originating from the atrloventricular groove, especially if Doppler analysis shows flow within the mass? Conversely, absence of flow may indicate luminal obstruction by thrombus. Aortic aneurysms may also appear as echocardiographlc masses that occupy a similar anatomic location. Because they also display blood flow, they may be confused with aneurysms of the coronary vessels. Other lesions to be considered in the differential diagnosis of an extracardlac mass include perlcardial cysts, tumors, inflammatory pencardial masses, or localized hematomas 3 Coronary artery aneurysms are detected in 1 2% to 4 9% of patients undergoing anglography and are present in 1.4% of postmortem examinations. 4 They are either saccular or fusiform in shape. Saccular aneurysms involve part of the coronary artery circumference, whereas fusfform lesions involve the entire vessel circumference. 5 Tunlck and colleagues, restricting their definition of aneurysms to only those with a saccular appearance, established an incidence of only 0.2% of 8,422 anglograms 6 Aneurysms most commonly involve the RCA. followed by the LAD, circumflex,
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Fig 3. Transesophageal echocardiogram, longitudinal plane, showing a long-axis view of the right coronary aneurysm anterior to the right atrium and proxP mal ascending aorta (outlined by arrows) The largefustform aneurysm extends the length of the RCA, and its large lumen appears as two masses as the ectatlc artery is transected longitudinally in this long-axis view AO, aorta, LA, left atrium; RA, right atrium
and left main coronary arteries. Although atherosclerosas is more commonly associated with aneurysms in the United States, Kawasaki's disease is the most common cause throughout the world. Other causes include congemtal anomalies, polyartentis nodosa, connective tissue diseases, trauma (including coronary angioplasty), and systemic lupus erythematosis. 4 Coronary artery aneurysms are often asymptomatlc, although Tunick and colleagues noted that saccular aneurysms were directly adjacent to severe coronary stenoses in 95% of their cases. 6 Angina is thus a common presenting complaint in symptomatic individuals. Although myocardial ischemia is usually caused by underlying atherosclerotic coronary disease, distal embohzation of intra-aneurysmal
thrombus may also produce lschemia or infarction. Although rare, aneurysm rupture is another complication of these lesions. T r e a t m e n t depends on the cause of the aneurysm. M o r e than 50% of aneurysms caused by Kawasaki's disease resolve within 1 to 2 years, and coronary artery bypass grafting ( C A B G ) is indicated only when coronary stenoses are progressive. 4 For patients with C A D , treatment is based on the extent of their coronary disease, not the aneurysm per se. If C A B G is performed, some authors r e c o m m e n d aneurysm resection to avoid the possibility of future rupture or embolization. 4,7,s However, diffuse aneurysmal disease usually precludes resection
REFERENCES
1 Qumn VJ, Baloch Z, Chandrasekaran K, et al' Coronary artery aneurysm masquerading as a paracardlac mass on transesophageal echocardiography Am Heart J 127.441-443, 1994 2. Tunlck PA, Slater J, Pasternack P, et al' Coronary artery aneurysms A transesophageal echocardiographlc study Am Heart J 118.176-179, 1989 3 Reeder G, Khandheria BK, Seward JB, et al" Transesophageal echocardiography and cardiac masses. Mayo Chn Proc 66.11011109, 1991 4 Wright WP, Alpert MA, Mukerj1 V, et al' Coronary artery aneurysms--A case study and literature review. Anglology 42'672679, 1991 5 Waller BF, Orr CM, Slack JD, et al: Anatomy. histology, and
pathology of coronary arteries. A review relevant to new lnterventional and imaging techniques--Part IV. Chn Cardiol 15.675-687, 1992 6. Tunlck PA, Slater J, Kronzon I, et al' Discrete atherosclerotlc coronary artery aneurysms A study of 20 patients J Am Coll Cardlol 15 279-282, 1990 7. Lazarus A, Donzeau-Gouge P, Spauldmg C, et al' Surgical treatment of an atherosclerotic aneurysm of the left main coronary artery Am Heart J 123"222-224, 1992 8 Selke KG, Vemulapalll P, Brodarlck SA, et al Giant coronary artery aneurysm Detection with echocardlography, computed tomography, and magnetic resonance imaging Am Heart J 121' 1544-1547, 1991