Interact CardioVasc Thorac Surg 2008;7:664-666. doi:10.1510/icvts.2007.171777
© 2008 European Association of Cardio-Thoracic Surgery
Negative results - Congenital |
Right ventricular aneurysm following modified Norwood-Sano operation for hypoplastic left heart syndrome
Mohsen Karimia,
Ahmed Farouka,
John Storkb and
Hani A. Henneina,*
a Rainbow Heart Center, Department of Pediatric Cardiothoracic Surgery, Rainbow Babies and Children's Hospital, Case Western Reserve School of Medicine, 11100 Euclid Avenue, Cleveland, OH, USA
b Department of Pediatric Anesthesiology, Rainbow Babies and Children's Hospital, Case Western Reserve School of Medicine, Cleveland, OH, USA
Received 16 November 2007;
received in revised form 20 March 2008;
accepted 27 March 2008
*Corresponding author. Tel.: +1-216-844-3058; fax: +1-216-844-3517.
E-mail address: hani.hennein{at}case.edu (H.A. Henneina).
 |
Abstract
|
|---|
Hypoplastic left heart syndrome is a rare congenital heart defect characterized by underdevelopment of left-sided heart structures, including the aortic arch. The contemporary surgical management of this anomaly includes the Norwood procedure and provision of pulmonary blood flow by either a modified Blalock-Taussig shunt (MBTS) or a right ventricle-to-pulmonary artery (RV-PA) conduit, commonly referred to as the Sano shunt. We report on an unusual complication of the Sano shunt, that of a giant right ventricular pseudoaneurysm occurring at the shunt insertion site.
Key Words: Hypoplastic left heart; Sano shunt; Right ventricular aneurysm
|
1. Introduction
|
|---|
Hypoplastic left heart syndrome (HLHS) is an anomaly of inadequately developed left heart structures, a condition that is uniformly fatal without treatment. The incidence is between 4 and 9% among all patients with congenital heart disease (CHD) [1]. The contemporary surgical management of HLHS is a palliative procedure described by Norwood and his associates in 1983 [2], where the right ventricular output is directed to the systemic circulation, the hypoplastic arch is augmented, a non-restrictive interatrial communication is established, and pulmonary blood flow is re-established by a systemic to pulmonary artery shunt [2]. A recent modification of the classic Norwood operation is the provision of pulmonary blood flow by means of a right ventricle-to-pulmonary artery conduit as described by Sano and his associates [3]. Benefits of the Sano shunt may include improved coronary perfusion as a consequence of decreasing the diastolic steal associated with a standard systemic to pulmonary shunt, and a resultant greater degree of hemodynamic stability, particularly in the early postoperative period [4, 5]. Known complications of the Sano shunt include shunt narrowing and thrombosis, pulmonary under- and over-circulation due to patient–shunt mismatch, central pulmonary artery stenosis at the site of shunt insertion, along with ventricular dysfunction and arrhythmias. We are reporting a case of pseudoaneurysm formation at the Sano insertion site at the right ventricle and surgical management of this rare but life threatening complication.
|
2. Case report
|
|---|
A full-term male presented with the prenatal diagnosis of critical aortic stenosis, hypoplastic left ventricle, and aortic arch hypoplasia. He underwent a modified Norwood–Sano operation, augmenting the arch with the native divided main pulmonary artery. Pulmonary blood flow was provided by means of a 6-mm PTFE Sano shunt interposed between an infundibulotomy and the patched distal end of the divided main pulmonary artery. The patient had an uneventful postoperative recovery, however, three weeks following hospital discharge the patient presented with poor weight gain and worsening tachypnea. A chest X-ray demonstrated mildly increased pulmonary vascular markings and markedly anteriorly displaced sternum. An echocardiogram revealed preserved global right ventricular function, a widely patent neoaortic arch, and an unrestrictive interatrial communication. However, there was an aneurysm at the base of the Sano shunt measuring 3-cm in largest diameter displacing the shunt anteriorly. A multislice CT-scan with 3D reconstruction confirmed the presence of the aneurysm, 2.8 cm in greatest dimension, the roof of which was feeding the Sano shunt (Fig. 1).
The patient was taken to the operating room for resection of the aneurysm and revision of the shunt. After full heparinization, an 8 Fr arterial cannula was secured to a 3.5 mm PTFE graft that had been sewn to the left femoral artery. His midline sternotomy was carefully entered just enough to cannulate the right atrium. Cardiopulmonary bypass was initiated, the patient was cooled to 20 °C and under fibrillatory arrest the aneurysm was dissected and mobilized. The large aneurysm was seen to be arising from the Sano insertion site on the right ventricular outflow tract (Fig. 2a). The aneurysmal sac was excised in total, and the large mouth of the ventricular defect was patched with a bovine pericardial patch. The Sano shunt was reanastomosed to the bovine pericardial patch to re-establish right ventricular to pulmonary artery continuity (Fig. 2b). Follow-up echocardiogram one week after discharge demonstrated preserved ventricular function with no residual defects and a widely patent Sano shunt. The final pathology of the aneurysm sac was that of attenuated smooth muscle wall with granulation tissue and fibrosis consistent with false aneurysm.
View larger version (86K):
[in this window]
[in a new window]
|
Fig. 2. (a) Intraoperative photograph of the right ventricular aneurysm. (b) Post repair photograph showing resection of the aneurysm wall, bovine pericardial patch closure of the ventriculotomy, and reanastomosis of the proximal Sano shunt to an opening in the bovine pericardial patch.
|
|
|
3. Discussion
|
|---|
The large pseudoaneurysm we report appears to be an unusual complication of the Sano shunt that occurred early after an otherwise uneventful Norwood–Sano operation. Potential causes could be pulmonary arterial stenosis at the distal anastomosis along with endocarditis which were ruled out. The most likely causes are the ‘coring out’ of the infundibulotomy site and incorporating only epicardial layer for the proximal anastomosis which may have weakened the ventricular wall. The presence of free pulmonary regurgitation of the non-valved conduit and systemic ventricular pressure in the aneurysm likely contributed to the aneurysmal expansion. We routinely use a somewhat larger size Sano shunt and are assertive in coring out the infundibulotomy site hoping to avoid the occurrence of early inter-stage shunt stenosis and related cyanosis. It may be, however, that somewhat over-sizing the shunt, in conjunction with assertive coring out of the infundibulotomy, may portend the patient to a greater risk of aneurysm formation.
The major advancement in the interstage mortality and morbidity in a patient with HLHS has primarily been the refinement of intra- and postoperative care to decrease the occurrence of early myocardial dysfunction and cardiovascular adverse consequences. The hemodynamic implication of the aneurysm formation early after stage one palliation imposes an additional risk factor for increase in morbidity and mortality prior to the second stage palliation. Therefore, the preoperative and operative management of these complex patients are the paramount to a successful outcome. We have found the technique of grafting the femoral artery with a PTFE conduit into which an arterial cannula could be placed, a generally useful technique for complex re-entry operations. We elected to close the defect with a patch of bovine pericardium and reattached the proximal end of the shunt to the patch. Ventricular fibrillation was utilized in this case in order to avoid widely dissecting and cross-clamping the fragile neoaorta.
An unusual case of a giant ventricular pseudoaneurysm and its surgical management following a modified Norwood–Sano operation is reported. Etiologic factors may have been the size of the conduit, the size and conduct of the infundibulotomy, along with the presence of free pulmonary regurgitation in a weakened RV at the site of ventriculotomy. This reported case underwent successful aneurysmectomy and reestablishment of RV-PA continuity with satisfactory postoperative outcome.
|
References
|
|---|
- Fyler DC, Buckley LA, Hellenbrand WE. Report of the New England regional infant cardiac program. Pediatrics 1980;65:375–461.[Medline]
- Norwood WI, Lang P, Hansen DD. Physiologic repair of aortic-atresia-hypoplastic left heart syndrome. N Engl J Med 1983;308:23–26.[Medline]
- Sano S, Kawada M, Yoshida H, Kino K, Irie H, Aoki A, Mitani H, Nakamura K, Inoue M. Norwood procedure to hypoplastic left heart syndrome. Jpn J Thorac Cardiovasc Surg 1998;46:1311–1316.[Medline]
- Sano S, Ishino K, Kawada M, Arai S, Kashara S, Asai T, Masuda Z, Takeuchi M, Ohtsuki S. Right ventricle-pulmonary artery shunt in first stage palliation of hypoplastic left heart syndrome. J Thorac Cardiovasc Surg 2003;126:504–509.[Abstract/Free Full Text]
- Pizarro C, Malec E, Maher KO, Januszewska K, Gillding SS, Murdison KA, Baffa JM, Norwood WI. Right ventricle to pulmonary artery conduit improves outcome after stage I Norwood for hypoplastic left heart syndrome. Circulation 2003;108, Suppl 1, II155–II160.[Medline]
|
|
Top
Abstract
1. Introduction