Ann Thorac Surg 2006;81:2313-2315
© 2006 The Society of Thoracic Surgeons
Case report
Right Superior Vena Cava Draining in the Left Atrium: Anatomical, Embryological, and Surgical Considerations
Guido Oppido, MD
*
,
Carlo Pace Napoleone, MD,
Simone Turci, MD,
Alessandro Giardini, MD,
Roberto Formigari, MD,
Emanuela Angeli, MD,
Gaetano Gargiulo, MD
Pediatric Cardiac Surgery Unit, S. Orsola-Malpighi Hospital, University of Bologna Medical School, Bologna, Italy
Accepted for publication May 25, 2005.
* Address correspondence to Dr Oppido, Pediatric Cardiac Surgery Unit, S. Orsola-Malpighi Hospital, Via Massarenti, n. 9, Bologna, 40138 Italy (Email: guidooppido{at}yahoo.com).
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Abstract
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A newborn, with SDS (S = situs viscero-atrialis solitus, D = D-loop of the ventricles, S = solitus, normally related great arteries) anomalous drainage of the right superior vena cava in the left atrium, intact atrial septum, and anomalous drainage of the right superior pulmonary veins in the right superior vena cava, underwent surgical repair at our institution. This rare cyanotic, congenital, cardiac malformation is herein described with particular regard to its anatomical, embryological, and surgical implications.
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Introduction
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The anomalies of systemic venous return are an extremely heterogeneous group of congenital malformations whose characteristics may range from completely normal physiology to severe forms of right-to-left shunt requiring surgical treatment. Mazzucco and co-workers [1] classified the anomalies of the systemic venous return into five groups according to their surgical implications.
Anomalous drainage of the right superior vena cava into the left atrium is one of the rarest variants of systemic venous return anomalies characterized by right-to-left shunt physiology and cyanosis. It is usually diagnosed early in life, but it can be occasionally discovered in older age, presenting with cyanosis, cardiomegaly, dyspnea, cerebral emboli, or abscesses.
A 2.6 kg African newborn boy was delivered after 36 weeks of gestation by Caesarean section. The patient was admitted to our institution due to persistent cyanosis and respiratory distress unresponsive to elective intubation and mechanical ventilatory support.
On arrival his vital signs were stable with an oxygen saturation of 85% on room air. Echocardiography showed SDS (S = situs viscero-atrialis solitus, D = D-loop of the ventricles, S = solitus, normally related great arteries) isolated left atrial drainage of the right superior vena cava. The atrial septum was intact with the fossa ovalis lying in the right-sided atrium, thus confirming a situs atrialis solitus. No others cardiac anomalies were detected.
The baby underwent cardiac catheterization (Fig 1) to better define this rare anatomic setting, showing an additionally anomalous drainage of the right upper lobe pulmonary veins in the superior vena cava and consequently into the left atrium. The inferior vena cava was normally draining into the right atrium, and the atrial septum was confirmed as intact.
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Fig 1. Cardiac catheterization: injection of dye into the innominate vein shows the right superior vena cava (RSVC) completely draining into the left atrium (LA). There is no passage of dye from the left to the right atrium (RA). The catheter enters the left atrium passing through the fossa ovalis valve. (* = atrial septum; LV = left ventricle.)
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Forty days after birth the baby underwent surgical repair (Fig 2) on conventional cardiopulmonary bypass. Body temperature was lowered to 34°C and cardioplegic cardiac arrest was avoided. Superior caval cannulation was performed in its uppermost portion.
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Fig 2. Intraoperative view of the right superior vena cava (RSVC) receiving three right upper lobe pulmonary veins (*). (Arrow = atrial septum; RAA = right atrial appendage; Ao = aorta; LA = left atrium.)
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The right superior vena cava was clamped and transected just above the three right upper lobe pulmonary veins, and the atrial end was closed with a 7-0 absorbable monofilament double running suture. As a result, the three pulmonary veins were left to drain in the left atrium. The cranial portion of the right superior vena cava was then anastomosed with a 7-0 PDS running suture to the tip of the right atrial appendage, achieving a gradient-less, tension-free anastomosis. The baby was weaned from cardiopulmonary bypass with low doses of inotropes and was taken to the postoperative intensive care unit with stable hemodynamics. The postoperative course was uneventful with extubation on postoperative day 1 and discharge home on postoperative day 10.
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Comment
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Left atrial drainage of the right superior vena cava with atrial situs solitus is a cyanotic congenital malformation that occurs mostly in association with partial anomalous pulmonary venous drainage into it, either with or without sinus venosus defect. Van Praagh and co-workers [2] hypothesized that this malformation could be due to the lack of formation, or involution, of the common wall that normally separates the right upper pulmonary veins and the superior vena cava, although this common wall hypothesis is not accepted by other authors [3]. Consequently, a sinus venosus defect would always be associated with partial anomalous pulmonary venous connection [2]. Possibly, in this type of malformation the right atrial orifice of the superior vena cava may become stenotic or atretic due to the preferential flow into the left atrium during the fetal life, hence resulting in a bi-atrial or left atrial drainage of the right superior vena cava [4]. It is a matter of fact that an atretic connection between the right superior vena cava and the right atrium has been incontrovertibly documented in some reports [5–6]. Nevertheless, left atrial drainage of the right superior vena cava has also been described in absence of anomalous pulmonary venous connection, which would invalidate this theory, unless it is theorized that the fusion would occur between the posterior wall of the right superior vena cava and the anterior wall of the embryonic common pulmonary vein in its unbranched portion, which afterward would be completely incorporated into the left atrium.
Also in this case, the preferential flow into the left atrium would make the caval orifice become stenotic or even atretic, transforming a potential sinus venosus defect into the unusual malformation herein described.
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References
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- Mazzucco A, Bortolotti U, Stellin G, Gallucci V. Anomalies of the systemic venous returna review. J Card Surg 1990;5(2):122-133.[Medline]
- Van Praagh S, Carrera ME, Sanders SP, Mayer JE, Van Praagh R. Sinus venosus defectsunroofing of the right pulmonary veins—anatomic and echocardiographic findings and surgical treatment. Am Heart J 1994;128(2):365-379.[Medline]
- Anderson RH, Webb S, Brown NA, Lamers W, Moorman A. Development of the heart(2) Septation of the atriums and ventricles. Heart 2003;89(8):949-958.[Free Full Text]
- Van Praagh S, Geva T, Lock JE, Nido PJ, Vance MS, Van Praagh R. Biatrial or left atrial drainage of the right superior vena cavaanatomic, morphogenetic, and surgical considerations–report of three new cases and literature review. Pediatr Cardiol 2003;24(4):350-363.[Medline]
- Kahwaji I, Ramaciotti C, Nikaidoh H, Leonard S, Harris K, Lemler M. Images in cardiovascular medicine. Echocardiographic diagnosis of anomalous drainage of the superior vena cava into the left atrium Circulation 2003;107(11):1560-1561.[Free Full Text]
- Samir K, Fraisse A, Rauzier JM, Kreitmann B. Anomalus drainage of the right superior vena cava to the left atrium Eur J Cardiothorac Surg 2003;23(6):1051.[Free Full Text]
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Abstract
Introduction
