Asian Cardiovasc Thorac Ann 2008;16:78-80
© 2008 Asia Publishing EXchange Ltd
Conduit from Hypoplastic Right Ventricle to Pulmonary Artery in Tricuspid Atresia
Muhammad M Amanullah, FRCS C-Th,
Asif Hasan, FRCS C-Th,
Richard Kirk, FRCP1
Division of Congenital Cardiac Surgery, Department of Cardiothoracic Surgery
1 Division of Pediatric Cardiology, Department of Cardiology, Freeman Hospital, Newcastle upon Tyne, United Kingdom
For reprint information contact: Muhammad M Amanullah, FRCS C-Th, Tel: 44 191 233 6161, Fax: 44 191 223 1417, Email: mmamanullah{at}doctors.org.uk, Division of Congenital Cardiac Surgery, Department of Cardiothoracic Surgery, Freeman Hospital, High Heaton, Newcastle upon Tyne NE7 7DN, United Kingdom.
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ABSTRACT
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Tricuspid atresia with transposition of the great arteries produces single ventricle physiology. Ultimate goals of neonatal palliative operations are to provide optimum anatomic and physiologic conditions for a Fontan procedure. A modification of the Norwood procedure is reported, with an aorto-pulmonary anatomosis, utilizing the hypoplastic right ventricle as the pulmonary outflow conduit, avoiding a left ventriculotomy and preserving its function with excellent recovery. We believe this technique has not been previously published in the English literature.
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INTRODUCTION
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Tricuspid atresia (TA) with transposition of the great arteries (TGA); a form of single ventricle physiology, is frequently associated with aortic arch anomaly. Diastolic function and compliance of the systemic ventricle is an important predictor of outcome. The ultimate goal of neonatal palliative operations is to provide optimum anatomic and physiologic conditions for a future Fontan procedure. By utilizing the hypoplastic right ventricle as the pulmonary outflow conduit site, a left ventriculotomy and its subsequent associated dysfunctions can be avoided.
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TECHNIQUE
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An 8-day-old girl weighing 3.5 kg was antenatally diagnosed with TA, hypoplastic right ventricle, TGA with a non-restrictive ventricular septal defect (VSD), and good left ventricular function (Figures 1
and 2).
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Figure 1. Morphology of tricuspid atresia with TGA hypoplastic aortic arch and VSD. ASD = Atrial septal defect, HRV = Hypoplastic Right ventricle, IVC = Inferior vena cava, LA = Left atrium, LPA = Left pulmonary artery, LV = Left ventricle, MPA = Main Pulmonary artery, MV = Mitral valve, PDA = Patent ductus arteriosus, RA = Right atrium, RPA = Right pulmonary artery, SVC = Superior vena cava, TVA = Tricuspid Valve Atresia.
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Figure 2. Echocardiographic features of the morphology. LV = left ventricle, RV = Right ventricle, VSD = Ventricular septal defect.
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After median sternotomy and thymectomy, cardiopulmonary bypass was established using carotid artery and ductal cannulation (supplying the lower half of the body) and single venous cannulation. Deep hypothermia of 18°C was achieved. A 5-mm polytetrafloroethylene (PTFE) graft was anastomosed to the pulmonary artery (PA). Flow was stopped to the lower half of the body. Perfusion to the head and neck was maintained via the carotid artery cannula and monitored using a cerebral oximeter (Somanetics – Tyco Healthcare, Troy, MI, USA). An aortic cross clamp was applied and cold blood cardioplegia was administered into the aortic root for myocardial preservation and repeated at 20-minute intervals. Aortic reconstruction was performed using autologous pulmonary artery and pulmonary artery homograft patch (Figure 3).
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Figure 3. Creation of Damus-Kay-Stansel, and an RV to PA conduit lying over the VSD. DKS = Damus Kay Stansel, LA = Left atrium, LPA = Left pulmonary artery, LV = Left ventricle, PA = Pulmonary artery, RA = Right atrium, RPA = Right pulmonary artery, Shunt = 5 mm Gortex tube, VSD = Ventricular septal defect.
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Via a right ventriculotomy the VSD was inspected and found to be 2 cm in diameter and non-restrictive. The 5-mm PTFE graft from the pulmonary artery was anastomosed to the right ventriculotomy (with coring out of the muscle at the anastomotic site). The cross clamp (to the lower half of the body) was removed after 124 minutes. After re-warming, CPB was discontinued after 306 min. Postoperative epicardial echocardiography showed satisfactory aortic repair with good left ventricular function and unrestricted flow across the VSD into the RV to the PA conduit.
The chest was left open and closed the next day. The postoperative course was uneventful with little inotropic support, no organ dysfunction and normal acid-base status. The baby was extubated after 60 hours and discharged from PICU to the ward on the 4th day and was home a week later.
She underwent angiography two months later, which demonstrated non-restrictive flow across the VSD, non-obstructed flow in the RV to PA conduit, and the neo-aorta also showed satisfactory flow (Figure 4). Left ventricular function was preserved. Postoperative echocardiogram confirmed the angiographic findings. The patient subsequently underwent cavo-pulmonary shunt (bi-directional Glenn’s Shunt) at the age of 7 months and made an uneventful recovery.
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Figure 4. Postoperative angiographic findings of a satisfactory repair. Damus Kay Stansel; Neo Aorta, Sano; Right ventricle to right pulmonary artery conduit.
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DISCUSSION
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Rarely do hearts possess a true solitary ventricle. Usually a well-developed ventricular chamber is associated with an incomplete, rudimentary or hypoplastic ventricle. Double inlet left ventricle and TA with TGA are two forms of single ventricle physiology.
The Fontan operation is increasingly being applied to patients with all forms of univentricular hearts. The goals of neonatal univentricular heart palliative operations are aimed to control pulmonary blood flow, relieve systemic outflow tract obstruction, and avoid heart block.1 Systemic outflow obstruction can be relieved by the Damus-Kaye-Stansel procedure. Diastolic dysfunction that reduces coronary perfusion pressure has emerged as a particularly important factor for early and late outcome following surgery and is related to diastolic runoff from the aorta in a systemic to pulmonary shunt (classic Norwood procedure).2 The RV-PA shunt (Sano modification of the Norwood procedure) improves myocardial performance and cardiac output increasing systemic oxygen delivery by preventing diastolic runoff.3 On the other hand, the effects of a ventriculotomy might harm myocardial performance and decrease systemic oxygen delivery.2 Some have the view that tricuspid atresia with TGA and LV as the single ventricle is one of the best forms to perform the classical Norwood. A Blalock-Taussig (BT) shunt would prevent any ventriculotomy.
In hearts with discordant VA connection, systemic blood flow must traverse the bulboventricular foramen (BVF). Matitiau et al2 found that the most important determinant of late BVF obstruction was its initial size. The BVF becomes restrictive with time causing progressive obstruction to the systemic blood flow, ventricular hypertrophy, and decreased ventricular compliance.4 If this is combined with a ventriculotomy the recovery of the systemic ventricle is delayed, putting these patients at a higher risk for the Fontan procedure.
Lan et al in their paper stated that of the 140 patients with single ventricle physiology, 35 (25%) had TA with TGA.1 The overall mortality for these patients was 50%. Systemic outflow obstruction results in ventricular hypertrophy and ischemia leading to LV dysfunction and remains a potential threat to the long-term outcome.5 The use of hypoplastic right ventricle as an outlet to pulmonary circulation avoids the concerns in the putative systemic ventricle. This modification should potentially improve the outcome, as there is improved myocardial oxygen delivery, which is one of the important determinants contributing to operative and inter-stage mortality.
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REFERENCES
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- Lan YT, Chang RK, Laks H. Outcome of patients with double-inlet left ventricle or tricuspid atresia with transposed great arteries. J Am Coll Cardiol 2004;43:113–9.[Abstract/Free Full Text]
- Matitiau A, Geva T, Colan SD, Sluysmans T, Parness IA, Spevak PJ, et al. Bulboventriclar foramen size in infants with double-inlet left ventricle or tricuspid atresia with transposed great arteries: influence on initial palliative operation and rate of growth. J Am Coll Cardiol 1992;19:142–8[Abstract]
- Sano S, Ishino K, Kawada M, Honjo O. Right ventricle-pulmonary artery shunt in first-stage palliation of hypoplastic left heart syndrome. Semin Thorac Cardiovasc Surg Pediatr Card Surg Annu 2004;7:22–31.[Medline]
- Mosca RS, Hennein HA, Kulik TJ, Crowley DC, Michelfelder EC, Ludomirsky A, et al. Modified Norwood operation for single ventricle and ventriculoarterial discordance: an improved surgical technique. Ann Thorac Surg 1997;64:1126–32.[Abstract/Free Full Text]
- Bradley SM, Simsic JM, McQuinn TC, Habib DM, Shirali GS, Atz AM. Hemodynamic status after the Norwood procedure: a comparison of right ventricle-to-pulmonary artery connection versus modified Blalock-Taussig shunt. Ann Thorac Surg 2004;78:933–41.[Abstract/Free Full Text]
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ABSTRACT
INTRODUCTION
