Ann Thorac Surg 1997;64:1829-1831
© 1997 The Society of Thoracic Surgeons
Case Report
Azygos Vein Agenesis and PAPVR: A Potential Surgical Hazard
Michael D. Black, MD,
Robert M. Freedom, MD
Divisions of Cardiovascular Surgery and Cardiology, The Hospital for Sick Children and The University of Toronto, Toronto, Ontario, Canada
Accepted for publication August 19, 1997.
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Abstract
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A 15-year-old boy underwent surgical correction of partial anomalous pulmonary venous return (right upper and middle lobe veins) into the high superior vena cava with an intact atrial septum using entirely autologous tissue. The rare association of azygos vein agenesis and partial anomalous pulmonary venous return should be emphasized to prevent the inadvertent inclusion of the anomalous systemic vein (hemiazygos vein) into the pulmonary venous circuit during the surgical repair.
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Introduction
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The repair of partial anomalous pulmonary venous return (PAPVR) into the right superior vena cava (SVC) has become a routine technical exercise, perhaps because in the vast majority of patients the abnormal drainage occurs at the SVC–right atrial junction. Infrequently, the pulmonary venous drainage occurs into the high SVC. As such, there remains lack of uniformity in the best approach to surgical repair. We would like to depict a modification that should greatly enhance subsequent systemic venous growth by the exclusive use of autologous tissues (a combination of autologous pericardium and viable right atrial tissue). The combination of PAPVR, an intact atrial septum, and azygos vein agenesis has only recently been described. Further discussion is thus justified to prevent the inclusion of an anomalous systemic vein (hemiazygos) into the pulmonary venous circuit.
After standard induction of anesthesia and placement of monitoring lines, the patient was placed on cardiopulmonary bypass by cannulating his ascending aorta, the inferior vena cava, and the innominate vein. The anomalous pulmonary venous return (right upper and middle lobe branches) entered the high SVC just below the level of an anomalous systemic vein. An abnormal systemic vein was recognized at this time, which was of similar size to the individual and anomalous pulmonary veins. This abnormal systemic vein's course was carefully traced, demonstrating origin from the left superior mediastinum. The right pleural space was opened, confirming the absence of an azygos vein. Mixed anomalous (pulmonary and systemic) venous return was confirmed, with the demonstration of an oxygen tension of only 63 mm Hg on an inspired oxygen fraction of 0.50. All pulmonary veins were traced to the pulmonary parenchyma, supporting our previous intrapericardial assumptions. Due to extensive distance between the brachiocephalic vein, right internal jugular confluence, and the right atrium, it became apparent that use of a conduit would be required for a tension-free repair.
After antegrade blood cardioplegia and the establishment of total cardiopulmonary bypass, a U-shaped right atriotomy was performed. This latter incision was created caudad to the region of the sinus node. The atriotomy fashioned allowed creation of a neo-SVC composed of autologous tissue and permitted intraatrial identification of the pulmonary venous ostia (Fig 1
) and creation of an atrial septectomy required for the repair. A pericardial baffle was used to complete the repair, by redirecting right pulmonary venous return into the left atrium.
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Fig 1. . (A) Repair of partial anomalous pulmonary venous return into the high superior vena cava (SVC) by creation of a U-shaped right atriotomy. The posterior wall of the neo-SVC is thus viable and retains future growth potential. Autologous pericardium was placed via the atriotomy, directing returns from the right upper and middle lobe veins across the atrial septectomy into the left atrium. Note the anomalous systemic vein entering the SVC after crossing the superior mediastinum. (B) An autologous pericardial patch was used to complete the anterior wall of the neo-SVC. The anomalous systemic vein was incorporated into the neo-SVC, thus draining into the right atrium. (AO = aorta; IVC = inferior vena cava; LPA = left pulmonary artery; RPA = right pulmonary artery.)
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Reconstitution of the neo-SVC was completed with absorbable monofilament sutures and autologous pericardium. Greater than 50% of the neo-SVC's circumference was composed of mechanically active and viable autologous tissue. The patient's heart was deaired and he was fully rewarmed. Normal sinus rhythm resumed with removal of the aortic cross-clamp. We weaned him from cardiopulmonary bypass without the need for inotropic support. Closure was as per routine. There was no evidence of SVC obstruction by pressure transducer measurement. A 6-month follow-up echocardiogram demonstrated a patent and unobstructed pulmonary and systemic venous connection. The patient continues to remain in normal sinus rhythm.
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Comment
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Operative correction of anomalous drainage of either the right upper and or the right middle lobe veins has become routine, particularly when the anomalous pulmonary veins are in close proximity to the atrial septal defect or right atrium. However, when they are distant, the surgical therapy becomes more complex, requiring the use of either prosthetic grafts [1], pericardial patches [2], or autologous tissue tunnels [3]. The objective regardless of the various surgical techniques should remain the avoidance of obstruction of pulmonary and systemic venous return and injury to sinus node or sinus node artery [4].
Creation of a neo-SVC using autologous tissue has been well described for PAPVR when the veins drain at the SVC–right atrial junction, and in association with a sinus venosus atrial septal defect [4–6]. Kioki and associates [7] in 1993 reported a repair of PAPVR into the high SVC with an intact atrial septum in association with azygos vein agenesis. However, they made no mention of an anomalous hemiazygos vein.
Our surgical repair, similar to that described previously by Williams and colleagues [4], was made in context with azygos vein agenesis and aberrant drainage of the hemiazygos vein into the right SVC, an association only recently reported [8]. The hemiazygos vein in the latter case drained the right and left intercostal veins from T-10 to T-6 curving rightward in the mediastinum, eventually entering the high right SVC.
This rare combination of azygos vein agenesis and PAPVR into the high SVC should be emphasized. Our patient represents a further description of an absent azygos vein in association with PAPVR into the high SVC. It is likely that previously unrecognized systemic veins emanating from the hemiazygos venous system and crossing the superior mediastinum have been mistakenly included in the surgical repair as an anomalous left pulmonary vein. This association of anomalous pulmonary and systemic venous return must be acknowledged. Misinterpreted as mixed anomalous pulmonary venous drainage, this anatomic association represents a potential surgical hazard by the inclusion of a systemic vein into the pulmonary venous circuit. Sampling venous oxygen tension with careful intrapleural inspection and confirmation of an absent azygos vein can prevent this latter mishap.
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Footnotes
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Address reprint requests to Dr Black, Division of Cardiovascular Surgery, The Hospital for Sick Children, 555 University Ave, Toronto, ON, Canada M5G 1X8 (e-mail: michael.black{at}mailhub.sickkids.on.ca).
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References
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- Kyger ER III, Frazier OH, Cooley DA, et al. Sinus venosus atrial septal defect: early and late results following closure in 109 patients. Ann Thorac Surg 1978;25:44–50.
- Stewart S, Alexson C, Manning J. Early and late results of repair of partial anomalous pulmonary venous connection to the superior vena cava. Ann Thorac Surg 1986;41:498–501.[Abstract]
- Puig-Massana M, Murtra M, Revuelta JM. A new technique in correction of partial anomalous pulmonary venous drainage. J Thorac Cardiovasc Surg 1972;64:108–13.[Medline]
- Williams WH, Zorn-Chelton S, Raviel AA, et al. Extracardiac atrial pedicle conduit repair of partial anomalous pulmonary venous connection to the superior vena cava in children. Ann Thorac Surg 1984;38:345–55.[Abstract]
- Kubota H, Furuse A, Kotsuka Y, Yagyu K, Hirata K, Murakawa Y. Midterm results of the rotation-advancement flap method for correction of partial anomalous pulmonary venous drainage into the superior vena cava. J Thorac Cardiovasc Surg 1996;112:1–7.[Abstract/Free Full Text]
- Warden HE, Gustafson RA, Tarnay TJ, Neal WA. An alternative method for repair of partial anomalous pulmonary venous connection to the superior vena cava. Ann Thorac Surg 1984;38:610–5.
- Kioka Y, Hiroyuki I, Yukio Y, Shunji S. A case of partial anomalous pulmonary venous connection to the high superior vena cava with intact atrial septum. J Jpn Assoc Thorac Surg 1993;41:1415–9.
- Cassiati A, Barberini F. Partial agenesis of the azygous vein: a case report. Anat Anz 1996;178:273–5.[Medline]
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Abstract
Introduction
