SESSION TITLE: Pediatric Global Case Reports
SESSION TYPE: Global Case Report
PRESENTED ON: Tuesday, October 28, 2014 at 01:30 PM - 02:30 PM
INTRODUCTION: Small pulmonary arteries in patients with congenital heart disease pose technical and physiologic challenges that may not improve with conventional systemic-to-pulmonary artery shunts. The internal mammary artery (IMA) offers advantages over standard shunts and has been used in selected patients. This case report describes use of the IMA for initial palliation and subsequent reconstruction of the pulmonary artery in an infant with an atretic-thrombosed right pulmonary artery (RPA) originating from the ascending aorta.
CASE PRESENTATION: A 26 day old male was transferred for evaluation of tachypnea and echocardiogram and CT scan showing absence of the RPA. Cineangiography revealed a normal origin of the left pulmonary artery, but a RPA was not identified. A non-patent vessel originating proximal to the innominate artery was thought to be the proximal RPA. On exploration, an atretic-thrombosed vessel originating at the junction of the aorta and innominate artery was followed to the hilum of the lung where it continued to a small patent pulmonary artery. A pericardial tube was anastomosed end-to-end to the hilar pulmonary artery and then end-to-side to the ascending aorta thus creating a systemic-to-pulmonary artery shunt. Planned catheterization did not show flow in the pericardial tube. At 3 months old, the patient was taken back to the operating room for end-to-end anastomosis of the right IMA to the distal RPA. Follow-up catheterization (10 months old) showed patency of the right IMA to the pulmonary hilar artery. The baby, subsequently, underwent anastomosis of the proximal right IMA to the proximal left pulmonary artery. Follow-up study (14 months old) showed the right IMA to be patent with growth of the right lung.
DISCUSSION: The IMA-to-pulmonary artery shunt has several advantages over conventional systemic-to-pulmonary artery shunts including better pliability, allows tension free anastomosis, is large enough to provide adequate blood flow to the pulmonary artery, grows with the patient, has flow adaptation, does not kink/stretch, and minimizes the risk of graft infection. Concern however about the IMA’s ability to increase pulmonary blood flow with resultant growth of the pulmonary arteries has limited its use as a systemic-to-pulmonary artery shunt. First described by Cobanoglu and colleagues as treatment of a child with absence of the RPA, congestive heart failure, pulmonary hypertension, and respiratory insufficiency. McKay has suggested that this procedure be limited to patients with very hypoplastic pulmonary arteries to which other shunts would not remain patent. Fifteen cases of IMA-to-pulmonary artery shunt in patients with CHD (diagnoses include pulmonary atresia, tetralogy of Fallot, transposition of the great arteries, ventricular septal defect with pulmonary valve stenosis, and single ventricle) have been reported in the literature. Nine of the patients had a prior shunt before IMA-to-pulmonary artery shunt and age at time of the IMA shunt ranged from 3 months to 16 years. Only four of the patients had preoperative and postoperative evaluation to determine growth of the pulmonary arteries. Growth of the pulmonary arteries is the desired outcome. In the 4 patients who were studied pre- and postoperatively, all had growth of the pulmonary arteries. These findings are consistent with what we saw in our patient. Growth of the RPA and right IMA allowed later reconstruction of the pulmonary artery by anastomosis of the proximal right IMA to the proximal left pulmonary artery thus establishing right ventricle to RPA continuity. Follow-up angiogram showed flow to the right lung through the right IMA, growth of the RPA, and growth of the right lung.
CONCLUSIONS: This is the first case reported of an infant who underwent IMA-pulmonary artery shunt in a noncyanotic patient with a small pulmonary artery with reestablishment of right ventricle to RPA continuity using the IMA. Growth and pliability of the IMA allowed reconstruction with pulmonary artery continuity. The IMA-to-pulmonary artery shunt should be considered in all patients requiring growth of pulmonary arteries before definitive repair.
Reference #1: Cobanoglu A, Abbruzzese P, Brauner D, Ferre B, Issenberg H, Starr A. Therapeutic considerations in congenital absence of the right pulmonary artery. Use of internal mammary artery as a preparatory shunt. J Cardiovascu Surg 1984;25(3):241-245.
DISCLOSURE: The following authors have nothing to disclose: Vicki Mahan, Randy Stevens, Cesar Mesia, Achintya Moulick
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