Ann Thorac Surg 2004;78:324-326
© 2004 The Society of Thoracic Surgeons
Case report
Anomalous origin of left coronary artery from right pulmonary artery in an infant with coarctation of the aorta
Anil Sivadasan Radha, DNBa,
Baiju Sasi Dharan, MChb,
Raman Krishna Kumar, DMa,
Suresh Gururaja Rao, MCh*b
a Divisions of Pediatric Cardiology and Pediatric Cardiac Surgery, Amrita Institute of Medical Sciences, Kochi, Kerala, India
b Departments of Cardiology and Cardiovascular Surgery, Amrita Institute of Medical Sciences, Kochi, Kerala, India
Accepted for publication June 13, 2003.
* Address reprint requests to Dr Rao, Amrita Institute of Medical Sciences, Kochi 682026, Kerala, India
e-mail: sureshgrao{at}aimshospital.org
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Abstract
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Anomalous origin of the left coronary artery from the right pulmonary artery is a very rare congenital anomaly, and its occurrence with coarctation of the aorta has been reported in very few patients. We report a neonate where the coronary anomaly was missed preoperatively and diagnosed after repair of the coarctation. The patient thereafter underwent ligation of the left anomalous coronary artery and had an uneventful convalescence.
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Introduction
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Anomalous origin of the left coronary artery (ALCAPA) from the right pulmonary artery (RPA) is a rare entity and its association with coarctation of the aorta has been reported in very few patients in world literature [1, 2]. The coronary anomaly is often overlooked at the initial evaluation. We report a case of ALCAPA from RPA in a neonate with critical post subclavian coarctation, associated with severe left ventricular dysfunction. This case report highlights the difficulties in the preoperative diagnosis of this uncommon association, and the ensuing surgical dilemma of choosing the operation with the least risk, in a critically ill child.
A male infant, 39 days old, weighing 2.8 kg presented to us with congestive heart failure. He was tachypneic and had absent femoral pulses. Chest roentgenogram showed cardiomegaly and pulmonary venous hypertension. Electrocardiography (ECG) showed features of left ventricular hypertrophy with 1-mm ST segment elevation in II, III, aVF, and ST depression in V1 to V3 leads. Two-dimensional echocardiography showed severe discrete post subclavian coarctation with severe left ventricular (LV) dysfunction (left ventricular ejection fraction [LVEF]: 20%) and significant pulmonary artery hypertension. The coronary origins were interrogated and thought to arise from the aorta with normal antegrade flows being demonstrated in them. The child underwent routine subclavian flap aortoplasty through a left postero-lateral thoracotomy with no residual gradient. During induction of anesthesia and the course of surgery, the child had persistent ST segment depression in limb leads, but the hemodynamics remained stable throughout the procedure.
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Fig 1. Parasternal short axis view on echocardiography shows that (arrow) the LMCA seems to arise from the AO in the normal fashion. (AO = aorta; LAD = left anterior descending artery; LMCA = left main coronary artery; PA = pulmonary artery.)
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Postoperatively, he could not be weaned from the ventilator over the next 48 hours because of tachypnea and hypercarbia. A bedside echocardiography on the second postoperative day showed persisting severe left ventricular dysfunction. There was flow reversal in the left coronary artery (LCA) but it "appeared" to arise normally from the aorta (Fig 1). Coronary angiography revealed the LCA filling by collaterals from the right coronary artery (RCA) and was opening into the RPA. After the procedure the child became hemodynamically unstable, needing very stiff inotropic supports. The hemodynamic instability and ST depression consistently worsened during hyperventilation and improved with hypercarbia. He was taken up for emergency surgery in a very hypotensive and critical state. Approaching through a median sternotomy, the LCA was found to arise from the undersurface of the RPA and on temporary occlusion of the LCA on table, the ST segment depression returned to baseline. In view of the precarious condition of the child, a short nonpump procedure of LCA ligation, close to its origin from the RPA, was expeditiously carried out. The patient tolerated the procedure well. The ST changes resolved over the next 4 days and the patient recovered uneventfully.
Predischarge ECG showed no ST elevation or depression and q waves in V5 to V6, I, and aVL. Echocardiography showed improved LV function with an ejection fraction of 40%. At one-month follow-up, the child had gained 400 g, ECG had normalized, and the ejection fraction remained at 40%.
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Comment
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The association of ALCAPA with coarctation has been reported in the literature, but this combination, where the origin of the anomalous LCA is from RPA, is distinctly rare. To our knowledge, there have been only three reported cases.[1, 2].
Today, the diagnosis of ALCAPA is largely established by echocardiography. The anatomic details and the retrograde flow patterns seen in the coronaries are diagnostic [3]. This case is unique because the coronary anatomy was keenly interrogated before surgery as the preoperative ECG was noted to be abnormal, but ALCAPA could not be demonstrated. The anomalous LCA from RPA coursed behind the aorta giving the erroneous impression of normal origin on echocardiography (Fig 1). The retrograde flow was clearly evident only after repair of the coarctation with a decline in PA pressures (Fig 2A).
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Fig 2. (A) Color Doppler showing retrograde flows in LAD and LCX. Note the blue flow in LAD (normal flow is red). (B) Color Doppler showing apparently normal flows in LAD and LCX. This pattern of flow was seen when there was significant acidosis and hypercarbia. (AO = aorta; LAD = left anterior descending artery; LCX = left circumflex artery; PA = pulmonary artery.)
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Hypercarbia improved hemodynamics, LV function, and produced normalization of ST segment, whereas hyperventilation consistently worsened hemodynamics and ST -T changes (Fig 3).
The antegrade flow seen preoperatively, and in periods of hypercarbia after coarctation (CoA) repair, was probably due to pulmonary artery hypertension (Fig 2B). Electrocardiography normalization and improved LV function during this period were due to the elimination of the coronary steal and improvement in coronary perfusion pressure.
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Fig 3. (A) 12 lead ECG showing ST depression and T wave inversion in V1 to V6. ST elevation is also obvious in inferior leads. (B) ST depression and T wave inversion is seen to be normalized. This was consistently observed during periods of respiratory acidosis. This ECG was taken when echocardiography showed antegrade flows in LCA. (ECG = electrocardiogram; LCA = left coronary artery; ST = segment elevations.)
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Major resource constraints and the lack of extracorporeal membrane oxygenation/LV assist devices made us choose the most expeditious option of LCA ligation. We recognize that a double coronary circulation is superior to a single coronary one and that this child might require a coronary artery bypass grafting in the future.
This report clearly illustrates that mere demonstration of close anatomic relation between LCA and the aorta with antegrade flows may not be adequate to rule out ALCAPA. In order to demonstrate its origin from RPA, the LCA need has to be traced behind the aorta in the parasternal short axis view by tilting transducer superiorly and to the right.
Anomalous origin of ALCAPA from the right pulmonary artery, in association with coarctation of the aorta, is a rare condition. Two-dimensional and Doppler flow pattern in the left coronary artery would appear to be normal and can be misleading because of associatedpulmonary artery hypertension. This report also highlights the importance of careful evaluation of ECG in the preoperative assessment of congenital heart disease. Severe LV dysfunction in a neonate, especially with ECG changes, should be interrogated thoroughly for ALCAPA including its origin from unusual sites.
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References
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- Levin S.E., Dansky R., Kinsley R.H. Origin of left coronary artery from right pulmonary artery co-existing with coarctation of the aorta. Int J Cardiol 1990;27:31-36.[Medline]
- Bharati S., Chandra N., Stephenson L.W., Wagner H.R., Weinberg P.M., Lev M. Origin of the left coronary artery from the right pulmonary artery. J Am Coll Cardiol 1984;3:1565-1569.[Abstract]
- Schmidt K.G., Cooper M.J., Silvermann N.H., Stanger P. Pulmonary artery origin of the left coronary artery: diagnosis by two-dimensional echocardiography, pulsed Doppler ultrasound and color flow mapping. J Am Coll Cardiol 1988;11:396-402.[Abstract]
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Abstract
Introduction
