Interact CardioVasc Thorac Surg 2007;6:826-827. doi:10.1510/icvts.2007.157669
© 2007 European Association of Cardio-Thoracic Surgery
Case report - Cardiac general |
Reconstruction of the right atrium with pulmonary artery homograft after resection of right atrial lipomatosis
Maurizio Rubinoa,
Abdel-Mohsen Hamadb,
Federico Reab,* and
Gino Gerosaa
a Department of Cardiologic, Thoracic and Vascular Sciences, Division of Cardiac Surgery, University of Padua, Padova, Italy
b Department of Cardiologic, Thoracic and Vascular Sciences, Division of Thoracic Surgery, University of Padua, Via Giustiniani, 2, 35128, Padova, Italy
Received 10 April 2007;
received in revised form 23 August 2007;
accepted 24 August 2007
*Corresponding author. Tel.: +39-049-8212237; fax: +39-049-8212249.
E-mail address: federico.rea{at}unipd.it (F. Rea).
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Abstract
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We present a case of large right atrial mass due to lipomatous hypertrophy of the interatrial septum and left lower lobe adenocarcinoma. Combined resections of the right atrial mass with reconstruction of the superior atriocaval junction and right atrial free wall defects with pulmonary artery homograft and wedge excision of the lung tumor were performed through median sternotomy.
Key Words: Atrial lipomatosis; Pulmonary homograft; Combined surgery
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1. Introduction
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Lipomatous hypertrophy of the interatrial septum (LHIS) is a rare benign tumor of the heart consisting of a nonencapsulated accumulation of mature fat, multivacuolated adipose cells, and enlarged cardiac myocytes. The incidence has been quoted at 1% of autopsy cases; however, higher incidence of up to 8% was found on transesophageal echocardiographic examinations (TEE) [1, 2].
Patients suffering from LHIS are often asymptomatic. However, congestive heart failure, atrial fibrillation, supraventricular tachycardia, palpitations and syncope are typical findings. The indication and best form of treatment for LHIS remain controversial.
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2. Case report
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During the diagnostic work up of the left lower lobe nodule for a 61-year-old man, computed tomographic (CT) scan revealed a 6x6 cm mass with fat density in the right atrium with encroachment on the caval openings (Fig. 1). On clinical evaluation, the patient had dyspnea on exertion, important asthenia and loss of weight; on examination there were congested neck veins, hepatomegally and bilateral pitting lower limb edema. Results of the chest and cardiac examinations and electrocardiogram were unremarkable. TEE confirmed the CT findings. The metastatic work up, including CT brain and bone scintigraphy, was negative and coronary angiography was normal. Concomitant surgical approach through median sternotomy was attempted. After median sternotomy and canulation of the aorta and vena cavae, the left lower lobe nodule was removed as wedge resection and sent for frozen section histopathological examination, which revealed adenocarcinoma with free cut margins; owing to difficulty in doing left lower lobectomy and mediastinal lymph node clearance through median sternotomy it was decided to postpone radical surgery to another sitting. Cardiopulmonary bypass was instituted and a right atriotomy was done; a mass was noted bulging from the IAS into the right atrial cavity. The endocardium over the mass was incised (Fig. 2a) and the tumor was enucleated from the interatrial septum, floor of the right atrium, the area between the entrance of the right pulmonary veins and finally resected with part of the free wall of the right atrium and the superior atriocaval junction; the interatrial septum was repaired without a patch and the free wall deficit was reconstructed with a pulmonary artery homograft; the left branch of the main pulmonary artery was anastomosed to the SVC and the other was oversewn; the pulmonary artery trunk was opened and used to reconstruct the atrial free wall (Fig. 2b).
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Fig. 1. Axial and 3-dimensional reconstruction CT scan in coronal plane showing lipomatous hypertrophy of interatrial septum projecting as a large mass into the right atrial cavity with encroachment of the mass on the cavity and opening of the superior vena cava.
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Fig. 2. Intraoperative views showing (a) the mass projecting from the septum into the atrial cavity, splitting of the septum (arrow) and beginning of dissection, (b) reconstruction of the RA with pulmonary artery homograft (small white arrow=SVC anastomosis; large white arrow=other branch of the pulmonary trunk; black arrow=RA free wall reconstruction).
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Weaning from cardiopulmonary bypass was easy with a junctional rhythm of 60 beats per minute (bpm); postoperatively, Holter monitoring did not reveal any further bradyarrhythmias, and so a permanent pacemaker implantation was unnecessary. Heart rate increased with time to more than 70 bpm. Pathologically, the cardiac tumor was consistent with lipomatosis and the lung tumor was a mixed adenocarcinoma (90% bronchoalveolar and 10% adenocarcinoma).
After one month the patient was subjected to completion by left lower lobectomy and mediastinal lymphadenectomy through a left posterolateral incision. Postoperative echocardiography and CT chest scan showed no residual atrial mass and proper function of the cavohomograft anastomosis. At 1.5 years' follow-up, the patient is doing well.
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3. Comment
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LHIS is a well-known but uncommon finding with the accumulation of adipose tissue in the interatrial septum. The usual location for LHIS is the interatrial septum with typical sparing of the foramen ovale, giving the lesion the characteristic dumbbell shape. However, LHIS was found to grow as a mass projecting into the right atrium (RA), which may involve the lateral wall and roof of the RA, and encroaching on the free wall of the left atrium. This lesion has also been shown to involve the caval veins, extending to the root of the aorta and down the atrioventricular groove alongside the coronary sinus, and in one case to appear as a nodular thickening of the circumferential RA wall, even involving the right atrial appendage [3].
Most patients affected are asymptomatic, and diagnosis usually occurs incidentally at imaging or at surgery. TEE is a simple and reliable diagnostic tool. TEE-findings of a bilobed atrial septum with high spin-echo intensity and a thickness of at least 15 mm is highly characteristic of LHIS [2]. Multislice computed tomography and cardiac magnetic resonance imaging in conjunction with fat-saturation techniques are highly sensitive and specific techniques to diagnose cardiac lipomatous lesions, and help to differentiate LHIS from other intracardiac masses, thus limiting the need for biopsy and histological conformation [1].
Some authors suggest that asymptomatic LHIS detected by chance should not be surgically corrected and that surgery be reserved only for patients with intractable arrhythmias, heart failure, thromboembolic sequelae, or inability to exclude liposarcomas. In our patient surgery was performed because of the presence of congestive heart failure. Also, complete surgical resection should not be attempted if it will compromise vital structures, taking into consideration the slow rate of expansion, rare malignant transformation and absence of recurrence after excision [4].
LHIS may require resection of a portion of the IAS and free atrial wall, necessitating repair with an autologous pericardium or a Dacron patch. Obstruction of the superior caval vein has been described in a number of reports; reconstructive enlargement of the SVC and the SVC-atrial junction with pericardium was performed by Breure and coworkers [5]; also, in the patient of Christiansen and coworkers [6], the atria were reconstructed using a Dacron patch and the resected part of the superior vena cava was replaced by a 14-mm Gore-Tex prosthesis that was anastomosed to the reconstructed right atrium. In our patient we used a pulmonary homograft because it is more pliable and, because of its anatomic configuration, can reconstruct both the SVC and the atrial wall instead of using two patches.
Aortic and pulmonary artery homografts have been used for different purposes in cardiac surgery and have made total repair of many complex congenital heart defects possible. The introduction of cryopreservation in the 1980s resulted in favorable cell viability and better durability [7]. The advantages of pulmonary artery homograft are the simplicity of the reconstruction of the atrial wall and atriocaval junction and avoidance of synthetic material; the potential complication in our patient is the possibility of calcification of the homograft and stenosis of the caval opening. However, after 1.5 years the homograft is functioning well.
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Acknowledgements
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We thank Dr Giuseppe Marulli and Dr Renato Bulf for the assistance in preparation of the manuscript.
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References
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Abstract
1. Introduction