Ann Thorac Surg 2004;78:1068-1070
© 2004 The Society of Thoracic Surgeons
Case report
Pseudoaneurysm of homograft placed in right ventricular outflow tract
Sudhir K. Pillai, DMa,*,
Haritha P. S. Reddy, BSa,
Snehal Kulkarni, DNB (Card), HODb,
Kona S. Murthy, MCh, HODb,
Kotturathu M. Cherian, FRACSc
a Department of Cardiology, Madras Medical Mission, Chennai, India
b Department of Paediatric Cardiology, Madras Medical Mission, Chennai, India
c Institute of Cardiovascular Diseases, Madras Medical Mission, Chennai, India
Accepted for publication July 3, 2003.
* Address reprint requests to Dr Pillai, Institute of Cardiovascular Diseases, Madras Medical Mission, 4 A Dr JJ Nagar, Mogappair 600 050, Chennai, India
icvd{at}eth.net
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Abstract
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Pseudoaneurysm of the right ventricular outflow tract after homograft placement is an infrequent complication after intracardiac repair for tetralogy of Fallot. We report two cases of pseudoaneurysm of right ventricular outflow tract after homograft placement for surgical repair of tetralogy of Fallot with pulmonary atresia.
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Introduction
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Pseudoaneurysm of right ventricular outflow tract (RVOT) rarely complicates surgical repair of tetralogy of Fallot with homograft placement. Its presentation may remain asymptomatic or may cause symptoms secondary to compression of surrounding structures, thromboembolism, and rarely rupture. We report 2 patients who had pseudoaneurysms of RVOT develop after surgical repair of tetrology of Fallot with homograft placement.
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Case reports
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Patient 1
A 16-year-old boy underwent surgical repair for tetralogy of Fallot with pulmonary atresia. A 27-mm pulmonary cryopreserved homograft was placed in the RVOT, the patent ductus was ligated and the ventricular septal defect was closed with a perforated patch. At routine annual follow-up the patient was asymptomatic with 98% systemic saturation (on room air). Echocardiographic evaluation showed a large aneurysm arising from the RVOT associated with left pulmonary artery stenosis. Cardiac catheterization revealed half systemic right ventricular pressure and a large pseudoaneurysm arising from the RVOT measuring 53.1 x 54.9 mm in maximum diameter (Fig 1), associated with left pulmonary artery stenosis resulting from compression.
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Fig 1. Right ventriculogram showing pseudoaneurysm (black arrow) arising from the left side of the homograft. White arrow indicates pulmonary artery. (MPA = main pulmonary artery; RVOT = right ventricular outflow tract.)
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The patient was treated surgically where the aneurysmal, dilated pulmonary homograft measuring 8 x 5 cm was excised and replaced with a 22-mm aortic homograft. The pseudoaneurysm was found arising from the ventriculotomy site along the proximal suture line of the homograft. Being wide-mouthed, the pseudoaneurysm could not be closed by direct suturing. Moreover, the homograft was found to be calcified with a forward gradient of 40 mm Hg associated with free pulmonary regurgitation. Therefore the decision for complete replacement of homograft was taken. The patient was discharged after an uneventful hospital stay.
Patient 2
An 8-year-old girl diagnosed to have tetralogy of Fallot with pulmonary atresia underwent surgical repair. A 20-mm cryopreserved pulmonary homograft was used as a right ventricle-pulmonary artery homograft conduit, left pulmonary artery plasty and perforated patch closure of the ventricular septal defect were also performed. On follow-up evaluation after 18 months, the patient was found to be asymptomatic with a systemic saturation of 98%. Chest roentgenogram showed cardiomegaly. Transthoracic echocardiography revealed a large pseudoaneurysm arising from the RVOT at the proximal end of the homograft along with right pulmonary artery (RPA) narrowing secondary to compression by the aneurysm. Cardiac catheterization showed a large pseudoaneurysm arising from the RVOT (at the proximal end of the homograft) measuring 49.2 x 66.5 mm and compressing the RPA with a gradient of 43 mm Hg across the RPA (Fig 2). The right ventricular pressure was found to be 70% of the systemic pressure. The patient was advised to undergo surgical repair for resection of pseudoaneurysm.
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Fig 2. Right ventricular outflow tract (RVOT) angiogram showing opacification of pseudoaneurysm (black arrow).
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Comment
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Both true and pseudoaneurysms can arise in the patients undergoing surgical repair involving RVOT. Most cases reported in the literature have undergone placement of RVOT patch. Instances of pseudoaneurysm development after placement of conduit or homograft between the right ventricle and the pulmonary artery are rare [1–3].
Pseudoaneurysm usually forms as a result of the dehiscence of the wall of the cardiac chamber, which permits seepage of blood into the surrounding space. There is no myocardial structure in the wall, which is mainly composed of fibrin and pericardium [4].
Pseudoaneurysms may remain asymptomatic or may cause symptoms secondary to rupture, compression of adjoining structures or thromboembolism.
The pathogenesis of pseudoaneurysm development after homograft placement is multifactorial [3]. Elevated right ventricular pressure was suggested as a factor predisposing pseudoaneurysm formation [2, 5]. Both the patients had elevated right ventricular systolic pressure, which may have caused increased mechanical strain at the proximal suture line. Other contributing factors described in the literature are local degradation of muscle, suture material and also suture technique [6]. Routinely we release the aortic cross clamp after the ventricular septal detect closure and distal homograft suturing. The proximal homograft sutures are taken on a beating heart, which also considerably reduces the cardioplegic time during surgery. With our patients, the aortic cross-clamp time was 75 minutes and 89 minutes and the total cardiopulmonary bypass time was 136 minutes and 165 minutes, respectively. The type of homograft (aortic or pulmonary) does not result in any increased susceptibility to pseudoaneurysm formation. Pseudoaneurysms can arise between the augmentation patch and the homograft or between the patch and the myocardium or between the homograft and the myocardium. In one of our patients the aneurysm was seen between the proximal suture line and the homograft. The role of local subvalvular muscle degradation leading to pseudoaneurysm formation is unresolved. It has been suggested by Levine and colleagues [2] that while suturing the homograft into the myocardium or an augmentation patch, the sutures be placed into the fibrous tissue of the valve along with the subvalvular muscle of the homograft.
Diagnosis of pseudoaneurysm is made by using two-dimensional echocardiography in which the image of the narrow neck of the pseudoaneurysm as against the wide neck of the true aneurysm can be seen. Color flow mapping is also helpful in establishing the continuity of blood flow between the pseudoaneurysm and the right ventricle. Chest roentgenogram may show widened cardiac silhouette or calcification of longstanding pseudoaneurysm.
Right ventricular angiography reveals a narrow neck aneurysmal structure with or without associated compression of pulmonary arteries.
The treatment should be an immediate resection in view of associated complications. The approach is mainly surgical. The location of the pseudoaneurysm should be well defined before the surgical approach is contemplated. Median sternotomy is usually done with utmost care, as the probability of perforation is high. The surgical treatment can be accomplished safely with low mortality and morbidity in these patients.
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References
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- Calabro R, Santoro G, Pisacane C, Pacileo G, Russo MG, Vosa C. Repeated syncopal attacks due to postsurgical right ventricular pseudoaneurysm. Ann Thorac Surg. 1999;68(1):252–254[Abstract/Free Full Text]
- Levine JC, Mayer JE Jr, Keane JF, Spevak PJ, Sanders SP. Anastomotic pseudoaneurysm of the ventricle after homograft placement in children. Ann Thorac Surg. 1995;59(1):60–66[Abstract/Free Full Text]
- Di Carlo D, de Leval MR, Stark J. Fresh. Antibiotic sterilized aortic homograft in extra-cardiac valved conduits. Long term results. J Thorac Cardiovasc Surg. 1984;32:10–14
- Van Tassel RA, Edwards JE. Rupture of the heart following myocardial intervention. Analysis of forty cases including nine examples of left ventricle false aneurysm. Chest. 1972;61:104–116
- Rosenthal A, Gross RE, Pasternac A. Aneurysm of right ventricular outflow tract. J Thorac Cardiovasc Surg. 1972;63:735–740[Medline]
- Moore WS, Hall AD. Late suture failure in the pathogenesis of anastomotic false aneurysms. Ann Surg. 1970;172:1064–1070[Medline]
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Abstract
Introduction
