Pseudoaneurysm of the mitral-aortic fibrosa: Myocardial ischemia secondary to left coronary compression

Pseudoaneurysm of the mitral-aortic fibrosa: Myocardial ischemia secondary to left coronary compression

Pseudoaneurysm of the Mitral-Aortic Fibrosa: Myocardial Ischemia Secondary to Left Coronary Compression Jorge Almeida, MD, Paulo Pinho, MD, J. Pinheir...

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Pseudoaneurysm of the Mitral-Aortic Fibrosa: Myocardial Ischemia Secondary to Left Coronary Compression Jorge Almeida, MD, Paulo Pinho, MD, J. Pinheiro Torres, MD, J. Mota Garcia, MD, M. Júlia Maciel, MD, C. Abreu Lima MD, P. Teixeira Bastos, MD, and M. Rodrigues Gomes, MD, Oporto, Portugal

In the current study we describe the cases of 2 patients operated on for left-sided endocarditis, who later had myocardial ischemia develop secondary to left coronary artery compression from a pseudoaneurysm of the mitral-aortic fibrosa. Because the symptoms of angina persisted despite medical treat-

Perivalvular abscesses, a fearful complication of endocarditis, are more common when the aortic valve is involved.1 With the development of aortic regurgitation, the striking of blood on the subaortic structures can lead to infectious jet lesions, which can evolve to abscess and later on to pseudoaneurysm formation.2 Transthoracic and 2-dimensional transesophageal echocardiography (TEE) with color Doppler are the leading tools in the identification of periaortic abscesses and their complications.3-8 In this study we present the clinical cases of 2 patients who had huge pseudoaneurysms of the intervalvular mitral-aortic fibrosa develop secondary to leftsided endocarditis.The 2 cases share the particularity of symptomatic myocardial ischemia secondary to left coronary artery compression by an aneurysm.

CASE REPORTS Patient 1 A 46-year-old man had surgery on November 2, 1994, for an aortic valve endocarditis complicated with a pseudo-

From the Center of Thoracic Surgery, S. João Hospital, Oporto, Portugal. Reprint requests: Jorge Manuel dos Santos Almeida, MD, Centro de Cirurgia Torácica, Hospital de S. João, 4200 Porto, Europa, Portugal (E-mail: [email protected]). Copyright © 2002 by the American Society of Echocardiography. 0894-7317/2002/$35.00 + 0 27/4/116875 doi:10.1067/mje.2002.116875

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ment, both patients had second surgeries. Myocardial revascularization was performed in 1 patient; the other patient, who had a severely depressed ventricular function, was given an orthotopic cardiac transplant. (J Am Soc Echocardiogr 2002;15: 96-8.)

aneurysm of the intervalvular fibrosa. The subaortic aneurysm was closed with a bovine pericardial patch, and the aortic valve was replaced by a bileaflet prosthesis (Carbomedics 25, Inc, Austin, Texas). The patient had no symptoms until August 1998 when he began to complain of angina with a severely abnormal stress test. A TEE was performed, which showed signs of compression of the left main trunk by the previously occluded pseudoaneurysm (Figure 1).The coronary angiography confirmed the compression of the left main trunk and showed an almost total occlusion of the proximal circumflex (CX) artery (Figure 2).The patient had a second operation on May 3, 1999, and the descending and CX coronary arteries were bypassed. Patient 2 A 27-year-old man with left valve endocarditis and class IV heart failure had an emergency operation on June 15, 1995. The aortic and mitral valves were replaced by bileaflet prostheses (Carbomedics 23R and Carbomedics 27, respectively). No perivalvular abscesses were identified at the time of surgery. After surgery the patient complained of effort dyspnea and angina, symptoms that were attributed to the severe systolic dysfunction evidenced by transthoracic transesophageal echocardiography (left ventricular [LV] dimensions were 73/61 mm). After the patient was evaluated for a transitory left hemiparesis, a TEE was performed in February 2000, and a huge pseudoaneurysm of the fibrosa, in communication with the aorta and the LV outflow tract, was identified.The aneurysm presented great expansion in systole because of the broad communication with the left ventricle (Figure 3).The left main trunk and the proximal segment of the CX artery were in narrow contact with the aneurysm (Figure 4).

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B Figure 1 TEE: Para-aortic, echo-dense mass corresponding to occluded pseudoaneurysm can be seen. Turbulent flow is observed in left main trunk (arrow). *Pseudoaneurysm; AO, ascending aorta; LA, left atrium.

Figure 3 A, Systole: Interposed between aorta and left atrium, pseudoaneurysm presents great expansion in systole because of broad communication with left ventricle (arrow). B, Diastole: Pseudoaneurysm, partially collapsed, fills from aorta (turbulent flow). *Pseudoaneurysm; AO, ascending aorta; LA, left atrium.

Figure 2 Left coronary angiography (60-degree left anterior oblique). Circumflex artery is pushed upward by pseudoaneurysm (arrowhead) and proximal segment of vessel is notoriously narrowed.

Coronary angiography showed compression of the CX artery, predominantly in systole, by the pulsatile aneurysm (Figure 5). On May 5, 2000, the patient was successfully given an orthotopic cardiac transplant.

DISCUSSION The anterior mitral leaflet is separated from the noncoronary and left coronary cusps of the aortic valve by a fibrous tissue designated as mitral-aortic intervalvular fibrosa. Infection secondary to endocarditis

Figure 4 Para-aortic cavity, corresponding to pseudoaneurysm, can be seen with flow inside it. Left atrium is not visible because it is squeezed by expanded aneurysm. Laminar flow is observed in left main trunk (arrow) and in proximal left anterior descending. Proximal segment of circumflex artery seems to be narrowed (arrowhead). *Pseudoaneurysm; AO, ascending aorta.

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Figure 5 A, Systole: Left coronary angiography (45-degree right anterior oblique). Proximal circumflex artery is squeezed by pseudoaneurysm (arrowhead). B, Diastole: Left coronary angiography (45-degree right anterior oblique). There is marked improvement of proximal circumflex artery lumen size.

can lead to an abscess and later to an aneurysm formation in communication with the left ventricle.The aneurysm can open in the pericardium leading to cardiac tamponade, open in a neighboring cavity, or stay blind in communication with the left ventricle.7 Although the left coronary artery is in proximity to the fibrosa, symptomatic ischemia secondary to compression of this vessel by an aneurysm ought to be uncommon as, to the best of our knowledge, only 1 case has been previously reported.8 In our first case, the aneurysm existed at the time of operation and was excluded with a bovine pericardial patch.The symptoms of angina occurred only 4 years after surgery.The proximal CX artery presented strongly narrowed and no variation in the vessel caliber was observed between systole and diastole. So we hypothesize that the left coronary artery could be involved in the healing fibrous process of aneurysm organization after being isolated from the left ventricle. In our second patient, although no abscess was identified on surgery, we believe that it could have been missed and later evolved to a pseudoaneurysm. The mechanism of ischemia was obvious, resulting from compression of the CX artery by the aneurysm expansion, which occurred predominantly in systole. The different attitude concerning treatment of these patients can be explained by the difference in their LV functions.In the second patient we decided on cardiac transplantation because we anticipated a poor outcome considering the severely depressed LV function.

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