Ann Thorac Surg 2007;84:2134-2135. doi:10.1016/j.athoracsur.2007.04.071
© 2007 The Society of Thoracic Surgeons
How To Do It
The Unifocal Bilateral Bidirectional Cavopulmonary Anastomosis
Antonio Amodeo, MD*,
Roberto M. Di Donato, MD
Cardiac Surgery Service of the Medical-Surgical Department of Pediatric Cardiology, Bambino Gesù Pediatric Hospital, Rome, Italy
Accepted for publication April 18, 2007.
* Address correspondence to Dr Amodeo, Dipartimento Medico-Chirurgico di Cardiologia Pediatrica, Ospedale Pediatrico Bambino Gesù, Piazza S. Onofrio, 4, Rome, 00165, Italy (Email: antonioamodeo{at}yahoo.it).
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Abstract
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We propose a new surgical technique to manage the presence of bilateral superior venae cavae in single ventricle patients, a recognized risk factor for both bidirectional Glenn anastomosis and Fontan completion. The idea is to convert two small, peripheral and competing bilateral bidirectional cavopulmonary anastomoses into a single, larger, and centrally located cavopulmonary connection. This technique, used in 2 patients, provides a symmetrical distribution of pulmonary blood flow and may, in fact, yield growth of the central pulmonary arteries as well as prevent thrombus formation.
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Introduction
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Systemic venous anomalies are no longer considered major risk factors for the Fontan operation. However, the presence of a bilateral superior vena cava still poses an increased challenge to the accomplishment of safe and reliable cavopulmonary anastomoses [1]. Most importantly, it produces flow stagnation at the level of the pulmonary arterial confluence, leading to increased risk of thrombus formation and unfavorable growth of the central pulmonary arteries [2]. Anecdotal modifications of surgical technique have been advocated to improve flow patterns from early suppression of the lesser superior vena cava to creation of end-to-side cavo-caval connection, including the interposition of a prosthetic innominate vein [3]. Herein, we present a modification of the bilateral bidirectional cavopulmonary anastomosis that possibly optimizes the growth of the central pulmonary arteries and reduces the risk of thrombus formation.
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Technique
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Two patients have received this surgical modification in the staging for a Fontan operation on July 20, 2006 and September 18, 2006, respectively.
Patient 1
A 10-month-old girl weighing 7.7 kg, with {A,D,D} heterotaxic syndrome, had a complete atrioventricular canal with right ventricular dominance, right aortic arch, pulmonary atresia with stenosis of pulmonary artery confluence, a mildly obstructed total anomalous pulmonary venous connection of the cardiac type (to the coronary sinus), and a persistent left superior vena cava draining into the coronary sinus without a communicating innominate vein. She had previously undergone an intrapericardial modified right Blalock-Taussig shunt associated with an extensive pulmonary patch arterioplasty. Her mean pulmonary artery pressure at preoperative heart catheterization was 18 mm Hg.
Patient 2
A 10 month-old boy weighing 7.2 kg of body weight, had transposition of the great arteries, straddling tricuspid valve with mitral atresia, left aortic arch, right pulmonary artery stenosis, and a persistent left superior vena cava into the coronary sinus without communicating innominate vein. He had formerly received a surgical atrial septectomy combined with pulmonary artery banding. The mean pulmonary artery pressure at the preoperative heart catheterization was 10 mm Hg.
Patients 1 and 2
In both cases, the operation was carried out through a repeat median sternotomy using normothermic cardiopulmonary bypass with unilateral superior caval cannulation (Fig 1). More precisely, the larger of the two superior venae cavae was cannulated, whereas the smaller one was left freely draining into the operative field and temporarily clamped during the anastomosis. The heart was kept beating throughout the procedure, except for a short period of aortic cross clamping in patient 1 to allow the unroofing of the coronary sinus for relieving the pulmonary venous obstruction. The pulmonary arterial anatomy was improved by an extensive polytetrafluoroethylene patch reconstruction of the pulmonary arterial confluence. Thereafter, both venae cavae were divided near the respective cavo-atrial junctions and extensively mobilized up to the jugular segments. The free ends of the two caval stumps were merged for a short distance (1.5 cm to 2 cm) in the middle, right under the aortic arch, to form a single vessel of larger caliber. This newly assembled, "Y"-shaped, venous collector was then end-to-side anastomosed to a correspondent opening in the cephalic aspect of the pulmonary arterial confluence, achieving a modified bidirectional cavopulmonary anastomosis. Both the cavo-caval and the cavopulmonary anastomoses were carried out with 7-0 absorbable running sutures. Completion of the procedure was then accomplished in the usual fashion.
Both patients had an uneventful recovery and are doing well at 6 and 4 months after surgery, respectively. A well-functioning modified bidirectional cavopulmonary anastomosis was demonstrated in both patients by two-dimensional and three-dimensional echocardiographic evaluation, and a postoperative cardiac catheterization in patient 1 showed no gradient across the anastomosis.
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Comment
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This experience shows that bilateral superior venae cavae in a single ventricle arrangement can be easily joined under the aortic arch to implement a single, confluent bidirectional cavopulmonary anastomosis. The technique used is safe, reproducible, and free of prosthetic material.
The rationale for this approach is that a "unifocal," cumulative, and centrally located bidirectional cavopulmonary anastomosis is supposedly more efficient than two small, peripheral and partially competing bidirectional cavopulmonary connections.
From a technical point of view, the accomplishment of this modified bidirectional cavopulmonary anastomosis is unaffected by the side of the aortic arch. Furthermore, its location can be easily adjusted to be slightly more rightward or leftward to allow for a sufficient offset with the predicted site of anastomosis of the future extracardiac inferior vena cava-to-pulmonary artery conduit connection. However, it can be speculated that a very large aorta might increase the degree of both divergence and tension of the caval confluence and be, in fact, a contraindication to this approach.
A longer follow-up is certainly necessary to establish the validity of this surgical variant and more experience is needed to show its widespread applicability to the different anatomical subsets. Nevertheless, at least conceptually, this surgical solution seems to provide a substantial advantage compared with other reported techniques. The ensuing, unopposed and symmetrical distribution of pulmonary blood flow may, in fact, yield growth of the central pulmonary arteries and prevention of thrombus formation.
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Acknowledgments
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We acknowledge Miss Francesca Brunone for the surgical drawing.
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References
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- McElhinney DB, Reddy VM, Moore P, Hanley FL. Bidirectional cavopulmonary shunt in patients with anomalies of systemic and pulmonary venous drainage Ann Thorac Surg 1997;63:1676-1684.[Abstract/Free Full Text]
- Iyer GKT, Van Arsdell GS, Dicke FP, McCrindle BW, Coles JG, Williams WG. Are bilateral superior vena cavae a risk factor for single ventricle palliation? Ann Thorac Surg 2000;70:711-716.[Abstract/Free Full Text]
- Vida VL, Leon-Wyss J, Garcia F, Castañeda AR. A Gore-Tex "new-innominate" vein: a surgical option for complicated bilateral cavopulmonary shunts Eur J Cardiothorac Surg 2006;29:112-113.[Abstract/Free Full Text]
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Abstract
Introduction
