Asian Cardiovasc Thorac Ann 2006;14:331-332
© 2006 Asia Publishing EXchange Ltd
Mycotic Aneurysm of the Right Coronary Artery
Tadashi Omoto, MD,
Kiyoshi Saito, MD1,
Toshitaka Kashima, MD,
Masato Kume, MD,
Shigeru Hosaka, MD,
Sosuke Kimura, MD
Department of Cardiovascular Surgery
1 Department of Pathology, International Medical Center of Japan, Tokyo, Japan
For reprint information contact: Tadashi Omoto, MD Tel: 81 3 3784 8000 Fax: 81 3 3784 8307 Email: tkashima{at}imcj.hosp.go.jp, Showa University Hospital, Cardiovascular Surgery, Hatanodai 1-5-8, Shinagawa-ku, Tokyo, Japan.
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ABSTRACT
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Mycotic embolism in patients with infective endocarditis is not uncommon, however, mycotic aneurysm of a coronary artery is very rare. We report the case of a 62-year-old woman with mitral valve endocarditis complicated by mycotic aneurysm of the right coronary artery. Mitral valve replacement and resection of the mycotic aneurysm with coronary artery bypass were performed.
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INTRODUCTION
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Mycotic aneurysm of a coronary artery is rare complication of infective endocarditis. Urgent aneurysmal resection and coronary bypass grafting should be performed due to inherent risks of rupture and late coronary complications.
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CASE REPORT
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A 62-year-old woman presented with dyspnea. On examination, pulse rate was 80 beats·min–1, body temperature was 36.4°C; and blood pressure was 150/90 mm Hg. A grade III/VI systolic murmur was heard over the mitral region. Echocardiogram demonstrated vegetation on the anterior mitral leaflet and prolapse of the posterior mitral leaflet with moderate to severe valvular regurgitation. Blood culture yielded 
-Streptococcus and intravenous administration of penicillin G was initiated. Electrocardiogram showed normal findings. Preoperative cardiac catheterization revealed a mycotic aneurysm of the right coronary artery (Figure 1
). After 4 weeks of treatment with antibiotics, the patient underwent mitral valve replacement with a 29 mm St. Jude Medical (St. Paul, MN, USA) prosthesis and removal of the coronary aneurysm (4 mm). Sequential coronary arterial grafting by saphenous vein to the right posterolateral segment artery and the right posterior descending artery was concomitantly performed. The postoperative course was uneventful. After completing a 4 week course of intravenous penicillin G, benzathine penicillin G was given for 3 months. Pathologic examination of the aneurysmal wall showed severe infiltration of inflammatory cells, diagnosed as mycotic aneurysm (Figure 2). Tissue cultures of the mitral valve and the mycotic aneurysm were negative. The patient recovered well and was free from recurrent infection six years after the operation.
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DISCUSSION
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Coronary embolisms complicating infective endocarditis are not an uncommon finding in infective endocarditis. Cates and coworkers reported 442 cases of subacute bacterial endocarditis, in which they found coronary embolisms in eight patients during life and eight at autopsy.1 The development of a coronary artery mycotic aneurysm is rare and there are only a few reports describing this problem.1–7 Cliff and colleagues reported a case with mycotic aneurysms of the left and right coronary arteries.3 Nebeker and coworkers reported mycotic aneurysm of a coronary artery associated with glomerulonephritis.4 McGee and colleagues reported a case with a ruptured mycotic aneurysm of the right coronary artery.5 Matsumoto and coworkers reported a case with mitral valve endocarditis complicated by acute myocardial infarction due to coronary embolism.6 Percutaneous transluminal angioplasty and subsequent mitral valve replacement were performed. Postoperative coronary angiography revealed formation of a mycotic aneurysm of the proximal left anterior descending artery (LAD), subsequently resection of the aneurysm and coronary bypass operation were performed. We present a rare case of concomitant coronary artery bypass and mitral valve replacement for the treatment of mycotic aneurysm of a coronary artery due to infective endocarditis.
This report illustrates the importance of identifying the presence of unruptured mycotic aneurysms prior to cardiac operations. Anticoagulation, hemodynamic changes and tissue edema associated with cardiopulmonary bypass may induce myocardial injury in patients with a coronary mycotic aneurysm. Although coronary angiogram is the only test that can reliably identify a mycotic aneurysm, routine coronary angiography for all patients with endocarditis does not seem warranted, especially for young patients without coronary risk factors. Transesophageal echocardiography and magnetic resonance imaging may assist the diagnosis.
The pathophysiologic mechanisms of the origin of mycotic aneurysms include embolic occlusion and sterile infarction of the vasa vasorum, direct invasion of the arterial wall, or arterial injury from immune complex deposition.7–8 Although infective endocarditis is often cured with antibiotics, many patients still require an operation during the active phase of infection. Although there is too little information to define operative indication or timing due to the small number of cases, urgent aneurysmal resection and coronary bypass grafting should be performed for a mycotic aneurysm of a coronary artery due to inherent risks of rupture and late coronary complications.
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ACKNOWLEDGMENTS
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We would like to thank Dr. Isamu Hirata for preparing the manuscript.
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REFERENCES
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- Cates JE, Christie RV. Subacute bacterial endocarditis: a review of 442 patients treated in 14 centers appointed by the Penicillin Trials Committee of the Medical Research Council. Q J Med 1951;20:93–130.[Medline]
- Herzog CA, Henry TD, Zimmer SD. Bacterial endocarditis presenting as acute myocardial infarction: a cautionary note for the era of reperfusion. Am J Med 1991;90:392–7.[Medline]
- Cliff MM, Soulen RL, Finestone AJ. Mycotic aneurysms–a challenge and a clue. Review of ten-year experience. Arch Intern Med 1970;126:977–82.[Abstract/Free Full Text]
- Nebeker HG, Hercz G, Feld GK, Stanley TM, Coburn JW, Kurokawa K. Postinfectious glomerulonephritis in a renal allograft associated with a mycotic aneurysm of a coronary artery. Am J Med 1984;76:940–2.[Medline]
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- Weinstein L, Schlesinger JJ. Pathoanatomic, pathophysiologic and clinical correlations in endocarditis (first of two parts). N Engl J Med 1974;291:832–7.[Medline]
- Weinstein L, Schlesinger JJ. Pathoanatomic, pathophysiologic and clinical correlations in endocarditis (second of two parts). N Engl J Med 1974;291:1122–6.[Medline]
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ABSTRACT
INTRODUCTION
