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Bidirectional Inferior Cavopulmonary Anastomosis: Pre-Fontan Interim Palliation

2017; Elsevier BV; Volume: 104; Issue: 4 Linguagem: Inglês

10.1016/j.athoracsur.2017.04.056

1552-6259

Muhammad Raees, Driss Mazhar, Jason Christensen, David A. Parra, Stacy A. S. Killen, David P. Bichell,

Vascular Anomalies and Treatments

We report a novel method of constructing an extracardiac bidirectional inferior cavopulmonary anastomosis. Our patient was a 4-month-old girl with complex single-ventricle anatomy and a small-caliber superior vena cava. A direct anastomosis from the inferior vena cava to the main pulmonary artery was constructed by using all autologous tissue. The resulting pathway remained patent and exhibited growth with age. Furthermore, a pulmonary arteriovenous malformation did not develop. This case demonstrates how a bidirectional inferior cavopulmonary anastomosis is feasible in the human and can provide similar hemodynamic results as the bidirectional superior cavopulmonary anastomosis. We report a novel method of constructing an extracardiac bidirectional inferior cavopulmonary anastomosis. Our patient was a 4-month-old girl with complex single-ventricle anatomy and a small-caliber superior vena cava. A direct anastomosis from the inferior vena cava to the main pulmonary artery was constructed by using all autologous tissue. The resulting pathway remained patent and exhibited growth with age. Furthermore, a pulmonary arteriovenous malformation did not develop. This case demonstrates how a bidirectional inferior cavopulmonary anastomosis is feasible in the human and can provide similar hemodynamic results as the bidirectional superior cavopulmonary anastomosis. The Supplemental Material can be viewed in the online version of this article [http://dx.doi.org/10.1016/j.athoracsur.2017.04.056] on http://www.annalsthoracicsurgery.org. The Supplemental Material can be viewed in the online version of this article [http://dx.doi.org/10.1016/j.athoracsur.2017.04.056] on http://www.annalsthoracicsurgery.org. The bidirectional superior cavopulmonary anastomosis, (BSCPA), a standard interim palliation for infants with single-ventricle physiology, can promote the formation of pulmonary arteriovenous malformation (PAVM) in more than 60% of patients by excluding hepatic venous effluent from the lungs, causing progressive cyanosis [1Kavarana M.N. Jones J.A. Stroud R.E. Bradley S.M. Ikonomidis J.S. Mukherjee R. Pulmonary arteriovenous malformations after the superior cavopulmonary shunt: mechanisms and clinical implications.Expert Rev Cardiovasc Ther. 2014; 12: 703-713Crossref PubMed Scopus (40) Google Scholar]. Significant resolution of PAVM may occur after the inferior vena cava (IVC) is included in the total cavopulmonary anastomosis (TCPA) [2Pike N.A. Vricella L.A. Feinstein J.A. Black M.D. Reitz B.A. Regression of severe pulmonary arteriovenous malformations after Fontan revision and “hepatic factor” rerouting.Ann Thorac Surg. 2004; 78: 697-699Abstract Full Text Full Text PDF PubMed Scopus (74) Google Scholar]. We report a novel method of constructing an extracardiac bidirectional inferior cavopulmonary anastomosis (BICPA), leaving the superior vena cava (SVC) intact and using all autologous tissue, with demonstrated growth potential. The patient was a 4-month-old girl with double-outlet right ventricle, D-malposed great arteries, pulmonary stenosis, and a straddling mitral valve. A small-caliber SVC observed intraoperatively suggested that the BSCPA approach would provide insufficient pulmonary blood flow and an intraoperative decision to perform a BICPA was made. At operation, the interatrial groove of Sondergaard was developed to ensure the BICPA pathway would reside within the groove, indenting the right atrium, impinging neither the right-sided pulmonary veins coursing posterior nor the SVC coursing anterior to the construct. The SVC was mobilized and the azygous vein divided. The main pulmonary artery was divided at the level of the pulmonary valve, and branch pulmonary arteries were fully mobilized to permit their inferior and rightward displacement, posterior to the SVC, to reside also in the interatrial groove. A direct anastomosis was formed between the IVC and the main pulmonary artery trunk (Fig 1). A 3-mm Gore-Tex (W. L. Gore & Associates, Flagstaff, AZ) systemic-to-pulmonary shunt was constructed between the aorta and the retroaortic pulmonary artery to augment pulmonary blood flow for the short-term to achieve targeted oxygen saturations (>80%). Postoperative examinations and echocardiograms revealed an unobstructed pathway from the IVC to both pulmonary arteries, unobstructed flow from the intact SVC to the right atrium, and no obstruction of the right-sided pulmonary veins. A nonocclusive thrombus developed within the IVC that resolved on medical management. The patient had no hepatomegaly, ascites, or any evidence of lower extremity edema. Her liver function tests, at the first postoperative day, showed an aspartate aminotransferase of 73 U/L (reference range, 25 to 75 U/L), alanine aminotransferase of 10 U/L (reference range, 4 to 54 U/L), total bilirubin of 0.7 mg/dL (reference range, 0.2 to 1.2 mg/dL), and an alkaline phosphatase of 70 U/L (reference range, 150 to 400 U/L). Preoperative cardiac catheterization showed a mean right atrial pressure of 7 mm Hg, mean right and left pulmonary arterial pressures of 15 and 13 mm Hg, respectively, a pulmonary blood flow (Qp)–to–systemic blood flow (Qs) ratio of 1.8:1, and a pulmonary vascular resistance of 1.2 units. Cardiac catheterization, 13 months after BICPA construction, showed a uniform pathway from the IVC to both branch pulmonary arteries, with a pressure of 14 mm Hg throughout and no evidence of PAVM (Fig 2). The patient underwent TCPA completion at age 23 months. Serial magnetic resonance angiograms showed a patent pathway that grew from 11.7 × 9.3 mm at 15 months to 15.9 × 11.3 mm at age 8 years (Fig 3, Supplemental Material). Her most recent clinic follow-up at age 9 years showed an oxygen saturation of 94% at rest and 97% with exercise. She has no exercise limitations by comparison to her twin and has not had episodes of cyanosis, shortness of breath, or chest pain and has not developed ascites, edema, or gastrointestinal complaints. She has exhibited a satisfactory increase in weight and height. Inferior cavopulmonary anastomosis was first reported by Mace and colleagues [3Mace L. Dervanian P. Losay J. et al.Bidirectional inferior vena cava-pulmonary artery shunt.Ann Thorac Surg. 1997; 63: 1321-1325Abstract Full Text PDF PubMed Scopus (10) Google Scholar] in 1993 using an intracardiac approach in 2 patients with contraindications to a Fontan completion. The first case of an extracardiac inferior cavopulmonary anastomosis used a bovine pericardial baffle that subsequently developed an obstructive false lumen [4Dodge-Khatami A. Aggarwal A. Taylor M.B. Maposa D. Salazar J.D. When the bi-directional Glenn is an unfavourable option: primary extracardiac inferior cavopulmonary connection as an alternative palliation.Cardiol Young. 2016; 26: 1247-1249Crossref PubMed Scopus (1) Google Scholar, 5Dodge-Khatami J. Aggarwal A. Taylor M.B. Maposa D. Salazar J.D. Dodge-Khatami A. Fontan completion in reverse order out of necessity: secondary Glenn after primary extracardiac inferior cavopulmonary artery connection.Cardiol Young. 2017; 27: 925-928Crossref PubMed Scopus (1) Google Scholar]. The feasibility, hemodynamic stability, and splanchnic tolerance of the BICPA have also been demonstrated by our case in addition to a few animal models and clinical reports [3Mace L. Dervanian P. Losay J. et al.Bidirectional inferior vena cava-pulmonary artery shunt.Ann Thorac Surg. 1997; 63: 1321-1325Abstract Full Text PDF PubMed Scopus (10) Google Scholar, 6Mace L. Dervanian P. Weiss M. Daniel J.P. Losay J. Neveux J.Y. Hemodynamics of different degrees of right heart bypass: experimental assessment.Ann Thorac Surg. 1995; 60: 1230-1237Abstract Full Text PDF PubMed Scopus (18) Google Scholar]. PAVM is known to develop when hepatic effluent is withheld from the lungs. The presence of the hypothesized “hepatic factor” is corroborated by findings similarly seen in patients with liver disease and the resolution of PAVM after liver transplant [7Srivastava D. Preminger T. Lock J.E. et al.Hepatic venous blood and the development of pulmonary arteriovenous malformations in congenital heart disease.Circulation. 1995; 92: 1217-1222Crossref PubMed Scopus (304) Google Scholar]. The present case supports this premise, and further studies will serve to characterize the efficacy of the BICPA approach in preventing PAVM. Kinetic energy loss across the TCPA has been the subject of numerous recent studies and has resulted in variants of the TCPA directed at optimizing passive pulmonary blood flow kinetics. A Y-shaped graft connection from the IVC to the pulmonary arteries has similarly shown to balance the distribution of hepatic effluent as well as maximize efficiency [8Marsden A.L. Bernstein A.J. Reddy V.M. et al.Evaluation of a novel Y-shaped extracardiac Fontan baffle using computational fluid dynamics.J Thorac Cardiovasc Surg. 2009; 137: 394-403.e2Abstract Full Text Full Text PDF PubMed Scopus (162) Google Scholar]. The BICPA construct results in a similar Y-shaped conformation and may produce similar hemodynamic properties and hepatic effluent distribution (Fig 3). We show evidence that circumferential growth may occur with the all-autologous BICPA. The BICPA may also allow a graded increase in pulmonary blood flow with age as well as exercise that increases venous return from the lower body. Liver dysfunction may be a significant concern because of the early exposure to Fontan pressures. However, the results of our patient’s liver function tests to date have been within normal reference ranges. Further studies are required to elucidate the effect of the BICPA approach on the liver and balance potential risks with advantages for patients with unfavorable SVC anatomy. This case demonstrates how the geometry of an autologous pathway from the IVC to the main pulmonary artery within the interatrial groove is feasible in the human, without obstructing the vascular structures, and that splanchnic venous congestion is not a necessary consequence of the approach. Our experience of this single case indicates that application of BICPA as an interim palliation can provide similar hemodynamic results as the traditional BSCPA approach. The potential physiologic advantages of the BICPA over the BSCPA approach remain speculative but may include the delay for a TCPA while avoiding the formation of PAVM; however, further study of the concept is needed. 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