Ann Thorac Surg 2008;86:1670-1672. doi:10.1016/j.athoracsur.2008.04.083
© 2008 The Society of Thoracic Surgeons
Case Reports
Perforation of a Tricuspid Pouch Caused by Infective Endocarditis
Kiyohito Yamamoto, MD, PhD*,
Hisato Ito, MD,
Takane Hiraiwa, MD, PhD
Department of Cardiovascular Surgery, Hamamatsu Medical Center, Hamamatsu, Japan
Accepted for publication April 23, 2008.
* Address correspondence to Dr Yamamoto, Department of Cardiovascular Surgery, Hamamatsu Medical Center, 328 Tomitsuka, naka, Hamamatsu, Shizuoka, 432-8580, Japan (Email: k-yama{at}hmedc.or.jp).
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Abstract
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A 61-year-old man was admitted because of infective endocarditis. Echocardiography revealed the bicuspid aortic valve and a tricuspid pouch bulging into the right ventricle. Color Doppler demonstrated mild aortic regurgitation and left-to-right ventricular shunt through the lower part of the pouch. We successfully performed an aortic valve replacement and closed the interventricular communication. Infective endocarditis of the bicuspid aortic valve appeared to have caused left-to-right ventricular communication at the lower part of the tricuspid pouch.
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Introduction
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A tricuspid pouch is a saclike structure that bulges into the right ventricle near the interventricular membranous septum. A tricuspid pouch is believed to be formed during the process of the natural closure of a perimembranous ventricular septum defect (VSD). Idriss and colleagues [1] reported that a tricuspid pouch was observed in 12.2% of cases operated on for repair of VSD, and this is commonly seen in infants but rarely in adults. We experienced a rare adult case of infective endocarditis of a bicuspid aortic valve complicated with perforation of the tricuspid pouch. Infective endocarditis caused a perforation of the aortic valve, and then the aortic regurgitation jet collided with the lower part of the tricuspid pouch, and a left-to-right ventricular shunt appeared.
A 61-year-old man was admitted to our hospital with a fever. He had been diagnosed with bicuspid aortic valve and trivial aortic regurgitation 10 years previously. A left ventriculogram had also revealed a tricuspid pouch but not a left-to-right shunt. During this most recent hospitalization, transesophageal echocardiography revealed a pouch protruding into the right ventricle (Fig 1). Color Doppler echocardiography demonstrated a left-to-right ventricular shunt flowing through the lower part of the pouch. Color Doppler echocardiography also revealed mild aortic regurgitation and trivial tricuspid regurgitation; however, obvious vegetation was not detected. Blood cultures were positive and the causative organism proved to be Streptococcus sanguis. Therefore, he was diagnosed with infective endocarditis. Benzyl penicillin potassium and gentamicin sulfate were administered for a month, curing the infective endocarditis. The pre-dispositioning events for the endocarditis were unclear. A cardiac catheter demonstrated a left-to-right shunt at the ventricular level with a systemic-to-pulmonary flow ratio of 1.7. Aortic regurgitation was mild and the left ventricular end-diastolic and left ventricular end-systolic dimensions were 56.9 mm and 34.3 mm, respectively. We performed aortic valve replacement and closure of the left-to-right ventricular communication. At operation, on observation of the bicuspid aortic valve, the commissure between the right and left cusps was fused, and a perforation was detected at the noncoronary cusp. Observation through a right atriotomy revealed a pouch of 1.5-cm diameter adjacent to the septal leaflet of tricuspid valve. Interventricular communication of 2-mm diameter was detected at the lower edge of the pouch (Fig 2). First, the VSD was directly closed without incising the pouch. Horizontal mattress sutures of 5-0 polypropylene were placed with a small pledget over the pouch. Edge-to-edge repair between the septal and anterior leaflets was then performed. Finally, aortic valve replacement was carried out with a pericardial bioprosthesis (23-mm Carpentier-Edwards Perimount; Edwards Lifesciences, Irvine, CA). The patient's postoperative course was uneventful, and he was discharged to home on postoperative day 17.
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Fig 1. Preoperative transesophageal echocardiography. Echocardiography reveals that a tricuspid pouch protrudes into the right ventricle. Arrow indicates tricuspid pouch. (LA = left atrium; LV = left ventricle; RV = right ventricle.)
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Fig 2. Intraoperative view of the tricuspid pouch. The right atrium is opened to reveal a tricuspid pouch (1.5 cm in diameter), adjacent to the septal leaflet. The probe passed from the left to the right ventricle through the interventricular communication (arrow). (Ao = aorta; I = inferior; L = left; R = right; S = superior.)
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Comment
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A tricuspid pouch is formed during the process of natural closure of a peri-menbranous VSD. The regurgitation jet through the VSD collides with the septal leaflet of the tricuspid valve and causes a saclike structure to bulge into the right ventricle. The septal leaflet, which has many chordal attachments to the perimeter of the VSD, adheres to the margins of the VSD, shortening its chordae. As a result, the pouch covers the VSD, decreasing its effective orifice and left-to-right shunt [2]. Complications such as rupture, endocarditis, or thrombosis are unusual [3], whereas a tricuspid pouch can sometimes cause subpulmonary obstruction in association with transposition of the great arteries [4].
On the other hand, the majority of bicuspid aortic valve patients develop complications, such as aortic valve stenosis, acute aortic dissection, and infective endocarditis that require treatment. Particularly, a bicuspid aortic valve is more susceptible to infective endocarditis [5]. Therefore, we consider that in the case presented here, infective endocarditis of the bicuspid aortic valve initially caused a perforation of the noncoronary cusp and then regurgitation jet collided with the pouch. Then a communication seemed to occur at the thinnest part of the pouch.
It has been reported that incising a pouch is safe and essential for proper exposure and the secure closure of the true defect. The presence of the tricuspid pouch may lead a surgeon to close small false openings produced by the pouch rather than the actual VSD [1]. However, the tricuspid pouch in our case had already been closed and was thick and durable; thus, we performed a direct closure of the interventricular communication without incising the pouch.
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References
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- Idriss FS, Muster AJ, Paul MH, Backer CL, Mavroudis C. Ventricular septal defect with tricuspid pouch with and without transposition. Anatomic and surgical considerations. J Thorac Cardiovasc Surg 1992;103:52-59.[Abstract]
- Magara T, Onoe M, Yamamoto Y, Nojima T. Tricuspid pouch Ryoikibetsu Shokogun Shirizu 1996;13:112-121.
- Takaki A, Ogawa H, Wakeyama T, et al. Tricuspid pouch can cause systemic embolization in adulthood Circ J 2006;70:631-633.[Medline]
- Kaneko Y, Okabe H, Nagata N, Kanamoto S, Yamada S. Right ventricular obstruction by tricuspid pouch in simple ventricular septal defect Ann Thorac Surg 1998;65:550-551.[Abstract/Free Full Text]
- Lamas CC, Eykyn SJ. Bicuspid aortic valve—a silent danger: analysis of 50 cases of infective endocarditis Clin Infect Dis 2000;30:336-341.[Abstract/Free Full Text]
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Abstract
Introduction
