Ann Thorac Surg 2006;81:744-746
© 2006 The Society of Thoracic Surgeons
Case report
Right Ventricular Outflow Tract Stent as a Bridge to Surgery in a Premature Infant with Tetralogy of Fallot
Antonio Laudito, MD
a
,
b
,
c
,
*
,
Varsha M. Bandisode, MD
a
,
b
,
c
,
Jon F. Lucas, MD
a
,
b
,
c
,
Wolfgang A. Radtke, MD
a
,
b
,
c
,
William T. Adamson, MD
a
,
b
,
c
,
Scott M. Bradley, MD
a
,
b
,
c
a Division of Cardiothoracic Surgery, Medical University of South Carolina, Charleston, South Carolina, USA
b Division of Pediatric Cardiology, Medical University of South Carolina, Charleston, South Carolina, USA
c Division of Pediatric Surgery, Medical University of South Carolina, Charleston, South Carolina
Accepted for publication October 29, 2004.
* Address correspondence to Dr Laudito, Medical University of South Carolina, 96 Jonathan Lucas St, PO Box 25061, Charleston, SC 29425 (Email: laudito{at}musc.edu).
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Abstract
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Despite dramatic progress in neonatal cardiac surgery, prematurity and low birth weight remain risk factors for poor outcome. Attempts to delay intervention with supportive therapy have been shown to increase morbidity and mortality. We present a case of an 840 gram, 28-week gestation newborn with tetralogy of Fallot, in whom palliation was achieved with a right ventricular outflow tract stent. This management allowed subsequent successful complete repair.
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Introduction
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During the last 20 years dramatic progress has been made in neonatal cardiac surgery. However, both prematurity and low birth weight remain risk factors for poor outcome. On the other hand, attempts to delay complete repair with supportive therapy have been shown to increase morbidity and mortality [1, 2]. Thus successful management of the small, premature neonate with a congenital heart defect continues to challenge congenital heart programs.
A newborn with a prenatal diagnosis of tetralogy of Fallot was born by Cesarean section for maternal pre-eclampsia at 28 weeks gestation, weighing 840 grams. The baby required mechanical ventilation for prematurity-related respiratory failure. An echocardiogram revealed tetralogy of Fallot with multilevel right ventricular outflow tract obstruction. There was a moderate infundibular pulmonary stenosis. The pulmonary valve was bicuspid with an annulus diameter of 3 mm. The branch pulmonary arteries measured 2.5 mm on the right and 1.6 mm on the left. There was a small patent ductus arteriosus. Systemic oxygen saturations were above 90%, and the ductus arteriosus was allowed to close spontaneously.
During the next 2 weeks, ventilatory support was gradually weaned. However, systemic oxygen saturations declined to 70% to 75% in the setting of an increasing gradient across the right ventricular outflow tract. An attempt to pharmacologically reopen the ductus with prostaglandin E(1) was unsuccessful. At this point, the patient was 2 weeks old and weighed 970 g. A decision was made to place a right ventricular outflow tract stent in the cardiac catheterization laboratory through a right internal jugular vein cut-down approach. A 4-French Judkins catheter (Cook Inc, Bloomington, IN) was advanced through a sheath into the right ventricle. A coronary wire was passed across the right ventricular outflow tract into the right pulmonary artery. A pre-mounted 4 mm x 12 mm coronary stent (Medtronic AVE, Santa Rosa, CA) was placed to extend from below the level of the infundibular pulmonary stenosis to the mid-main pulmonary artery (Fig 1). The systemic oxygen saturation increased to 90% to 95%. At the conclusion of the case, the internal jugular sheath was replaced with a Broviac catheter. The infant was subsequently discharged home receiving aspirin at 9 weeks of age.
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Fig 1. Contrast injection in the right atrium shows the stent located in the right ventricular outflow tract and opacification of the pulmonary arteries.
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By week 12 of life, 10 weeks after the stent placement, systemic oxygen saturations had again decreased to 70%. Echocardiography suggested neoendothelial proliferation in the stent. The infant underwent complete surgical repair at 3 months of age (40 weeks gestational age), weighing 3.0 kg. An incision was made over the stent from the main pulmonary artery extending onto the right ventricular outflow tract. The stent was intact and without fractures. It was embedded in the right ventricular muscle and in the pulmonary valve tissue, requiring sharp dissection to be removed. The ventricular septal defect was closed through a ventriculotomy with a pericardial patch. A transannular patch was used to close the right ventricular outflow tract incision. The patient was weaned from cardiopulmonary bypass with minimal inotropic support (milrinone 0.5mcg/kg/min; dopamine 5 mcg/kg/min). The right ventricular/left ventricular pressure ratio was 0.76. The postoperative course was uneventful, and the infant was discharged home 7 days after surgery. Echocardiography prior to discharge showed a widely patent right ventricular outflow tract with a peak gradient of 9 mm Hg, and no residual ventricular septal defect.
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Comment
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Despite advances in neonatal cardiac surgery, prematurity and low-birth weight remain significant risk factors for poor outcome [3]. However, data from previous studies indicates that delay of complete repair to achieve weight gain may result in both morbidity and mortality during the period of medical management [1, 2]. Patients such as the one in this report thus present difficult management decisions. Potential surgical options included primary complete repair or palliation with a systemic-to-pulmonary shunt. Given this patient's weight, prematurity, and pulmonary status, we judged that either of these approaches carried significant risk. Instead we elected palliation by placement of a stent in the right ventricular outflow tract. This approach successfully provided a controlled increase in pulmonary blood flow. In comparison with palliation by a systemic-to-pulmonary shunt, the outflow tract stent avoided the difficulties of appropriate shunt size selection in a small patient and placement of a shunt to a hypoplastic branch pulmonary artery. It also allowed a period of weight gain from 1 to 3 kg, at which time a successful complete repair was carried out.
Placement of a stent in the right ventricular outflow tract has been previously reported, primarily to extend the life of an obstructed conduit between the ventricle and the pulmonary arteries [4]. Use of a stent to relieve muscular obstruction in the right ventricular infundibulum has also been reported in a small number of older children [5]. Potential limitations of this approach have included obstruction of the stent due to neoendothelial or muscular proliferation; stent fracture, especially when the stent is lying behind the sternum; and right ventricular outflow tract perforations [5]. These limitations can be minimized by limiting the length of time the stent is left in place.
In some patients, stent implantation in a patent ductus arteriosus may be an alternative nonsurgical approach to providing pulmonary blood flow [6]. Compared with stenting the right ventricular outflow tract, ductal stenting may have the disadvantages of diastolic runoff from the aorta with lower diastolic blood pressure and end-organ perfusion, a higher likelihood of neointimal proliferation, and the need for arterial vascular access during placement. In our patient, the approach of stenting the ductus arteriosus was not possible, as the ductus had closed prior to the intervention.
In summary, placement of a stent in the right ventricular outflow tract provided effective palliation in a low birth weight, premature neonate with tetralogy of Fallot. We have previously reported the use of palliative stents for aortic coarctation in 3 premature infants weighting <1300 gm [7]. In most cases, we prefer complete repair rather than palliation, irrespective of patient size. However, in selected neonates with very low birth weight and congenital heart disease, stent placement as a bridge to elective surgery may provide a useful approach.
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References
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- Chang AC, Hanley FL, Lock JE, Castaneda AR, Wessel DL. Management and outcome of low birth weight neonates with congenital heart disease J Pediatr 1994;124:461-466.[Medline]
- Reddy VM, McElhinney DB, Sagrado T, Parry AJ, Teitel DF, Hanley FL. Results of 102 cases of complete repair of congenital heart defects in patients weighing 700 to 2500 grams J Thorac Cardiovasc Surg 1999;117:324-331.[Abstract/Free Full Text]
- Wernovsky G, Rubenstein SD, Spray TL. Cardiac surgery in the low-birth weight neonate. New approaches Clin Perinatol 2001;28(1):249-264.[Medline]
- Ovaert C, Caldarone CA, McCrindle BW, et al. Endovascular stent implantation for the management of postoperative right ventricular outflow tract obstructionclinical efficacy. J Thorac Cardiovasc Surg 1999;118:886-893.[Abstract/Free Full Text]
- Gibbs JL, Uzun O, Blackburn MEC, Parsons JM, Dickinson DF. Right ventricular outflow stent implantationan alternative to palliative surgical relief of infundibular pulmonary stenosis. Heart 1997;77:176-179.[Abstract/Free Full Text]
- Alwi M, Choo KK, Latiff HA, Kandavello G, Samion H, Mulyadi MD. Initial results and medium-term follow-up of stent implantation in patent ductus arteriosus in duct-dependent pulmonary circulation J Am Coll Cardiology 2004;44(2):438-445.[Abstract/Free Full Text]
- Radtke WAK, Waller BR, Hebra A, Bradley SM. Palliative stent implantation for aortic coarctation in premature infants weighting <1500 g Am J Cardiol 2002;90:1409-1412.[Medline]
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Abstract
Introduction
