Coronary-to-Pulmonary Artery Collateral in Tetralogy of Fallot
Saket Agarwal, MCh,
Bana B Mishra, MS,
Kaushik Mukherjee, MS,
Deepak K Satsangi, MCh
Department of Cardiothoracic Surgery G.B. Pant Hospital New Delhi, India
Saket Agarwal, MCh, Tel: +91 11 2323 4242, Fax: +91 11 2667 2594, Email: saket9{at}hotmail.com, Department of Cardiothoracic Surgery, G.B. Pant Hospital, New Delhi, India.
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ABSTRACT
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Angiography in a 14-year-old boy with cyanosis since birth confirmed the diagnosis of tetralogy of Fallot with a subaortic ventricular septal defect, large overriding aorta, severe pulmonary stenosis, and a large collateral arising from the left circumflex artery. The collateral was isolated and ligated at its origin, and the patient underwent an uneventful repair with ventricular septal defect patch closure, infundibular resection, pulmonary valvotomy, and right ventricular outflow tract reconstruction with an autologous pericardial patch.
Key Words: Coronary Vessel Anomalies • Heart Defects • Congenital • Heart Septal Defects • Ventricular • Tetralogy of Fallot
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INTRODUCTION
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Coronary-to-pulmonary artery collaterals have been described primarily in patients with pulmonary atresia and ventricular septal defect. We describe a rare case of tetralogy of Fallot (TOF) with a collateral originating from the left circumflex coronary artery to the right pulmonary artery.
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CASE REPORT
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A 14-year-old boy was referred in New York Heart Association functional class II, with cyanosis since birth and dyspnea on exertion. There was no history of cyanotic spells. On physical examination, he had central cyanosis and grade III clubbing. His pulse rate was 86 beats per minute, with a regular rhythm. His blood pressure was 114/76 mm Hg (right upper arm, supine). Pulse oximetry revealed O2 saturation of 84%. Chest radiography indicated a right ventricular apex, large aorta, and pulmonary oligemia. An electrocardiogram showed sinus rhythm with evidence of right ventricular hypertrophy and right axis deviation; there was no evidence of ischemic changes. Echocardiography demonstrated a large subaortic ventricular septal defect (VSD), aortic override, and severe pulmonary infundibular and pulmonary valve stenosis. At cardiac catheterization and angiography, the diagnosis of TOF was confirmed, with a large subaortic VSD, a large overriding aorta, and severe pulmonary stenosis. The aortic root angiogram also showed a collateral of significant size arising from the left circumflex artery (Figure 1
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Figure 1. Aortic root angiogram in lateral view, showing a collateral arising from the left coronary artery system.
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Selective coronary angiography verified that the collateral arose from the left circumflex coronary artery near its origin, and continued towards the right pulmonary artery (Figure 2). There was good arborization of both pulmonary arteries. At surgery, the collateral was observed arising from the left circumflex artery. The left coronary circulation was otherwise normal. There were no large collaterals from the right side or the rest of the left system. The collateral was isolated and ligated at its origin from the coronary artery. The patient underwent an uneventful repair with VSD patch closure, infundibular resection, pulmonary valvotomy, and right ventricular outflow tract reconstruction with an autologous pericardial patch. He made a satisfactory recovery, and was discharged home on the 11th postoperative day.
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Figure 2. Selective left coronary injection in anteroposterior view, confirming a collateral arising from the left circumflex coronary artery system and going towards the right pulmonary hilum.
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DISCUSSION
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Coronary-to-pulmonary artery collaterals are thought to represent remnants of the splanchnic vascular system, and they normally regress with the formation of the pulmonary arterial system later in fetal life.1 However, they may persist when the central pulmonary arterial system fails to develop adequately. They have been described primarily in patients with pulmonary atresia and VSD, where an incidence of up to 10% has been reported.2 They have also been described in other rare situations such as congenital absence of a pulmonary artery, where the collateral serves as the primary source of blood supply to the involved lung.3
In patients with TOF, coronary artery anomalies as well as small fistulous communications between the coronary and pulmonary arterial systems have been described.4 In older patients with TOF, there is a theoretical increase in the incidence of major collaterals to the pulmonary circulation, but a collateral of significant size arising from the coronary arterial system has not been described previously. It is important to diagnose all such collaterals accurately preoperatively so that they can be dealt with appropriately at surgery. The possible adverse effects of a missed diagnosis include loss of effective myocardial protection in the operating room due to run-off of cardioplegia into the pulmonary vascular bed, and postoperative endotracheal bleeding. Therefore, we believe that preoperative angiography with an aortic root shot should be performed when there is suspicion of such a collateral, as in patients presenting late for surgery with relatively high preoperative oxygen saturation, or with suggestive findings on echocardiography.
All attempts should be made to tackle the collateral at the time of surgery, prior to the onset of cardiopulmonary bypass. There is usually a dual source of blood supply to the involved segments, and it is safe to ligate the collateral without unifocalization. However, if the collateral is missed at preoperative evaluation or not ligated during surgery, it can be closed with catheter-based devices, as demonstrated in cases of coronary artery fistula by Trehan and colleagues.5 There is also a theoretical possibility of the collateral causing run-off into the pulmonary vascular bed, significant enough to result in preoperative myocardial ischemia. However, there was no history of angina or electrocardiographic evidence of ischemia in this patient.
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REFERENCES
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- Amin Z, McElhinney DB, Reddy VM, Moore P, Hanley FL, Teitel DF. Coronary to pulmonary artery collaterals in patients with pulmonary atresia and ventricular septal defect. Ann Thorac Surg 2000;70:119–23.[Abstract/Free Full Text]
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- Dabizzi RP, Caprioli G, Aiazzi L, Castelli C, Baldrighi G, Parenzan L, et al. Distribution and anomalies of coronary arteries in tetralogy of Fallot. Circulation 1980;61:95–102.[Abstract/Free Full Text]
- Trehan V, Yusuf J, Mukhopadhyay S, Rangasetty UC, Mehta V, Gupta MD, et al. Transcatheter closure of coronary artery fistulas. Indian Heart J 2004;56:132–9.[Medline]
Asian Cardiovasc Thorac Ann 2009;
17:304-306
© 2009 by SAGE Publications
DOI: 10.1177/0218492309104743
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ABSTRACT
INTRODUCTION
