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© 2003 European Association of Cardio-Thoracic Surgery
Repair of adult Scimitar syndrome with an intra-atrial conduit
a Cardio-Thoracic Surgery Unit, St Luke's Hospital, Guardamangia, Malta
* Corresponding author. Tel.: +356-21-584926 Received June 10, 2002; received in revised form December 13, 2002; accepted December 16, 2002
The management of Scimitar syndrome in adulthood is controversial, with no guidelines for surgical correction. We present the case of a 66-year-old woman who presented late in life with Scimitar syndrome and a significant left-to-right shunt. We describe repair using an intra-atrial conduit from the anomalous vein to the foramen ovale, with a successful outcome.
Key Words: Scimitar syndrome; Dacron graft
Scimitar syndrome was first described by Cooper in 1836. This syndrome of partial or total anomalous pulmonary venous return of the right pulmonary veins to the inferior vena cava (IVC) was named ‘Scimitar syndrome’ by Neill in 1960 because the abnormal vessel can often be seen as a curvilinear density along the right heart border on plain chest radiography. Additional features in this syndrome such as hypoplasia and abnormalities of the vascular supply to the right lung, dextrocardia and abnormalities of bronchial segmentation are common; bronchiectasis is rare [1].
We present the case of a 66-year-old woman who had been reasonably well apart from being breathless on exertion and cyanosed. She had been pregnant three times but suffered two spontaneous abortions, and had been severely breathless during labour. Her dyspnoea had deteriorated in the 2 years prior to presentation, and she had developed left-sided pleuritic chest pain. Chest radiograph (Fig. 1) showed an abnormal shadow arising from the inferior margin of the right lung hilum suspicious of Scimitar syndrome. Transoesophageal echocardiography confirmed anomalous right pulmonary venous drainage, with venous return to the IVC.
Cardiac catheterisation displayed the aberrant vein (Fig. 2) and revealed a left-to-right shunt with a ratio of 2.3:1, with normal pulmonary artery pressures. She was referred for surgery on the basis of worsening dyspnoea and a significant shunt.
Following median sternotomy, cardiopulmonary bypass was established between bicaval cannulae and the ascending aorta. The core temperature was reduced to 20°C to allow for a brief period of circulatory arrest. The right atrium was opened and the IVC cannula was removed. Anomalous pulmonary venous drainage into the IVC, just below the cavoatrial junction, and a patent foramen ovale (PFO) were present. The PFO was enlarged and a 20mm Dacron tube graft was anastamosed between the anomalous vein and the PFO, diverting the pulmonary venous blood into the left atrium. The anterior wall of the IVC was augmented with a pericardial patch to obviate any obstruction caused by the shunt. On returning to normothermia, the heart was weaned from bypass in sinus rhythm without inotropic support. The patient made an uneventful recovery and went home on the eighth postoperative day. Six months later she remained free of symptoms, with an increased exercise tolerance, and a good quality of life. Transthoracic echocardiogram performed 1 year postoperatively demonstrated that the conduit had remained patent.
Functionally, Scimitar syndrome resembles an atrial septal defect (ASD), however, there are no guidelines for surgical correction in adults [2]. Its ‘infantile’ form, diagnosed <1 year presents with severe respiratory insufficiency, pulmonary hypertension and cardiac failure; and carries a poor natural prognosis [3]. In contrast, in the ‘adult’ form, diagnosed >1 year, haemodynamic changes are less marked. Left-to-right shunt is less than 50% in 82% of patients, pulmonary artery pressures are normal in 77% of patients and slightly elevated in a further 23%, and these patients lead a normal life without surgical correction [1]. However, in cases with a left-to-right shunt more than 50% of the patients develop dyspnoea, chest infections and pulmonary hypertension [2]. Our patient had a long history of well-compensated dyspnoea, however, her symptoms had markedly deteriorated over 2 years and investigation had revealed a shunt ratio QP/QS of 2.3. Prognosis after intracardiac repair of Scimitar syndrome is excellent in patients without pulmonary hypertension [4]. Various techniques for repair have been described. Honey suggested that operative management should differ according to the presence or absence of an associated ASD [5]. With an intact atrial septum, the anomalous vein may be reimplanted if possible into the back of the left atrium; otherwise, the anomalous venous return can be baffled through an existing or created ASD to the left atrium [5]. However, thrombosis and fibrosis may occur in the Scimitar vein that has been reimplanted in the left atrium, necessitating pneumonectomy in 50% of cases [6]. Dupuis also reported thrombosis of the anastomosis between the right pulmonary veins and the left atrium; this occurred immediately after surgery [7]. Baffling of the Scimitar vein to the left atrium was described by Kirklin in 1971. Baffling can be complicated by stenosis resulting in pulmonary venous obstruction—this is less common in the adult group (>1 year), especially more so in older patients [8]. Postoperative quantitative pulmonary perfusion scans demonstrated a 24% reduction in flow to the right lung, and seldom resulted in normal blood flow to the right lung [8]. Successful Inoue balloon percutaneous dilation of a stenotic inferior vena cava anastomosis has been described with good haemodynamic and symptomatic resolution [9]. Other techniques that have been used to correct Scimitar syndrome in adults include using the anterior wall of the right atrium to form a tunnel to divert the anomalous pulmonary vein to the left atrium, an extracardiac conduit using a 10mm diameter polytetrafluoroethylene graft and intrapericardial extracardiac baffling to the right superior pulmonary vein [2] There has been 1 case report utilising a 14mm Dacron graft interposed between the orifice of the anomalous pulmonary vein and an enlarged ASD [10]. In our patient, the distance between the orifice of the Scimitar vein and the PFO negated the use of an intracardiac patch and a 20mm interposition Dacron graft was used. The anterior wall of the IVC was then augmented to prevent any obstruction to flow. The large diameter size of the prosthetic conduit helps ensure long-term patency. The aims of surgery for correction of Scimitar syndrome in adults are to abolish the left-to-right shunt, to preserve drainage of the right lung through the Scimitar vein and to avoid thrombosis at the anastomosis. We believe that the use of an interposition Dacron graft between the Scimitar vein and the foramen ovale fulfills these criteria.
ICVTS on-line discussion Author: Dr. Antonio Corno, CHUV, Cardiac Surgery, 46 rue du Bugnon, CH-1011 Lausanne, Switzerland Date: 23-Jan-2003 06:40 Message: This very rare case of an adult patient with "scimitar syndrome" has been successfully treated with an intracardiac dacron conduit to deviate the anomalous pulmonary vein into the left atrium through the enlarged patent foramen ovale. It would be interesting to know from the Authors why they decided to use a dacron conduit instead of one in PTFE, since both sides of the conduit, the internal and the external, remain exposed to the blood flow. With this regard, they should inform the reader if the patient has been treated with antiplatelets or anticoagulants, and how long. doi:10.1016/S1569-9293(02)00120-2
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Abstract
1. Introduction
