Anesth Analg 2007;104:81-83
© 2007 International Anesthesia Research Society
doi: 10.1213/01.ane.0000250365.25480.c5
PEDIATRIC ANESTHESIA
Unrecognized Anomalous Origin of the Left Coronary Artery from the Pulmonary Artery as a Cause of Ventricular Fibrillation After Patent Ductus Arteriosus Ligation in an Infant
Elena Bafani, MD,
Avinash C. Shukla, MD, and
James A. DiNardo, MD
From the Department of Anesthesia, Children's Hospital Boston and Harvard Medical School, Boston, Massachusetts.
Address correspondence and reprint requests to Elena Bafani, MD, Department of Anesthesia, Children's Hospital Boston, 300 Longwood Ave., Boston, MA 02115. Address e-mail to elena.bafani{at}childrens.harvard.edu.
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Abstract
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We present a case of an infant who developed ventricular fibrillation after patent ductus arteriosus (PDA) ligation. The infant had unrecognized anomalous origin of the left coronary artery from the pulmonary artery before PDA ligation. Acute reduction in systemic pulmonary artery pressures after PDA ligation resulted in an abrupt reduction in left main coronary artery blood flow. After prompt resuscitation, cardiac catheterization confirmed the diagnosis of anomalous origin of the left coronary artery from the pulmonary artery. The infant subsequently underwent coronary artery translocation and recovered uneventfully.
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Introduction
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Anomalous origin of the left coronary artery from the pulmonary artery (ALCAPA) or Bland–White– Garland Syndrome is a rare congenital cardiac anomaly occurring in one of 300,000 live births, and generally occurring in isolation (1). ALCAPA has been reported in association with other cardiac lesions, including patent ductus arteriosus (PDA) (2).
We present the case of an infant with pulmonary hypertension secondary to a large PDA and additional lesions producing a high QP:QS who developed subendocardial ischemia and ventricular fibrillation after PDA ligation as the result of unrecognized ALCAPA. Ligation of the PDA resulted in an acute reduction in pulmonary artery pressure and left main coronary artery blood (LMCA) flow.
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CASE REPORT
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A 1-month-old infant, full term, 2.7 kg was scheduled for PDA ligation. The baby was born at 42-wk gestation, but was small for his gestational age (2.1 kg). He was noted to have dysmorphic features (abnormal digits, hypertelorism, low set ears, webbed neck, widely-spaced nipples) and genetic work-up revealed a 49 XXXXY anomaly. A failure to thrive evaluation included a transthoracic echocardiogram (TTE) which showed a large PDA with predominantly left to right flow, multiple small apical muscular ventricular septal defects (VSD), a large secundum atrial septal defect (ASD), and as well as a patent foramen ovale, mild mitral regurgitation, and systemic right ventricular and pulmonary artery pressures. The LMCA was noted to arise ectopically from the rightward portion of the left sinus of Valsalva and to have antegrade flow. As the PDA was found to be the largest contributor to this patient's high QP:QS and failure to thrive, surgical ligation of the PDA was planned.
After placement of a 24-gauge IV catheter, anesthesia was induced with etomidate, remifentanil, and vecuronium. The trachea was intubated via the right naris with a 3.0-mm endotracheal tube and a right radial arterial line was placed. Anesthesia was maintained with sevoflurane and a remifentanil infusion 0.05–0.1 mcg · kg–1 · min–1. A video-assisted thoracoscopic approach via the left hemithorax was planned. This approach proved to be technically unfeasible and the PDA was ligated via a limited left thoracotomy without difficulty. The patient remained hemodynamically stable throughout the procedure and an arterial blood gas before closure of the thoractomy revealed a pH of 7.32, Paco2 of 56 mm Hg, and Pao2 of 199 mm Hg with an Fio2 of 1.0.
As the team was preparing to transfer the patient to the Cardiac Intensive Care Unit, he suddenly developed ventricular fibrillation. The rhythm was rapidly identified and the Pediatric Advanced Life Support protocol initiated. The infant was defibrillated and converted to sinus rhythm. Dopamine 5–7.5 mcg · kg–1 · min–1 was required to maintain his arterial blood pressure and perfusion. A prophylactic lidocaine infusion was started at 40 mcg · kg–1 · min–1. Ischemic changes were present on ECG. Emergency TTE showed severe left ventricular (LV) dysfunction consistent with an immediate postarrest scenario. The patient was transported to the intensive care unit uneventfully.
Over the next several hours, the ECG changes slowly improved, although inotropic support remained necessary. Repeat TTE several hours after arrest revealed only slightly improved ventricular function. No further delineation of coronary anatomy over that defined by previous examinations was possible. Persistent ischemic ECG changes characteristic of LMCA insufficiency (3) (Fig. 1), depressed LV function, unexplained cardiac arrest, and suspicious coronary anatomy by TTE lead the intensive care unit team to suspect ALCAPA. The decision was made to perform a cardiac catheterization in order to further delineate the coronary anatomy. The catheterization revealed a large ASD and several small restrictive apical muscular VSDs, a QP:QS > 3:1 and an anomalous LMCA arising from the underside of the main pulmonary artery (Fig. 2). His pulmonary artery pressure was 50/18 mm Hg while his ascending aortic pressure was 77/53 mm Hg consistent with high pulmonary blood flow (predominantly at the level of the ASD) into a relatively low resistance pulmonary arterial bed.
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Figure 1. The infant's electrocardiogram demonstrating the ischemic changes consistent with compromise of the left main coronary artery (LMCA) distribution. There is diffuse ST segment depression in conjunction with ST elevation in aVR > V1.
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Figure 2. Still-frame of the infant's pulmonary arteriogram in the lateral projection demonstrating the unusual origin of the left main coronary artery (LMCA) from the underside of the main pulmonary artery (MPA). The most common origin of the LMCA in ALCAPA is the leftward, posterior sinus of the pulmonary artery. A surgical clip is seen occluding the patent ductus arteriosus (PDA).
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Transposition of the LMCA to the aorta and closure of the ASD were scheduled and performed uneventfully the following morning. The patient was tracheally extubated 2 days later and after 5 days was discharged home on captopril and furosemide.
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DISCUSSION
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Surgical mortality for PDA ligation is low (<1%). The common morbidities include inadvertent ligation of the left pulmonary artery or descending aorta, recurrent laryngeal nerve injury, excessive bleeding due to PDA disruption, and chylothorax. Myocardial ischemia in infants with a large PDA is common. A large PDA with left to right shunting reduces aortic diastolic blood pressure via runoff in the pulmonary vascular bed and volume loads the LV. Myocardial ischemia after PDA ligation is an unexpected finding.
Dramatic changes occur in the coronary circulation in infants with ALCAPA within the first weeks of life. While the fetus remains in utero, the heart will develop quite normally. Initially after birth, the still relatively high pulmonary vascular resistance and pulmonary artery pressure allow the myocardium supplied by the anomalous artery to remain well perfused. In the few days after birth, as pulmonary vascular resistance decreases so too does the pressure in the pulmonary trunk. Subsequent compromise of LV subendocardial perfusion develops because of both reduced antegrade flow and to frank retrograde flow in the LMCA with resultant coronary steal. In addition, all antegrade left coronary artery flow is deoxygenated mixed venous blood. Severe LV dysfunction and associated mitral insufficiency generally develop rapidly. Left untreated, 90% of infants will not survive the first year of life (4). A small subset of patients survives beyond infancy due to rapid development of collaterals from the right coronary artery.
In this case, the presence of a large PDA provided maintenance of high pulmonary artery pressure and antegrade delivery of relatively oxygenated blood to the LMCA. Subendocardial perfusion was potentially jeopardized by the increased LV end-diastolic pressure present due to a high QP:QS from the PDA, ASD, and VSDs. We hypothesize that surgical ligation of the PDA acutely reduced coronary perfusion pressure and oxygen delivery to the LV with resultant ventricular fibrillation. A previous case report described chronic LV failure developing 2 mo after ligation of an apparently uncomplicated large ductus arteriosus in a 1-year-old girl. Two years later, deterioration had progressed to a terminal stage (5).
Suspicion of ALCAPA arose in this patient based on the clinical course after PDA ligation and the unusual origin of the LMCA as delineated by echocardiography. In this case, echocardiography failed to delineate the true origin of the LMCA. Cardiac catheterization remains the "gold standard" for delineation of coronary artery anomalies. Anomalous origin of a coronary artery from the pulmonary artery should be considered when coronary ischemia follows an acute reduction in pulmonary artery pressure. The diagnosis of ALCAPA, once made, is an indication for urgent surgery. Excellent surgical results have been reported after re-establishment of a normal antegrade dual coronary artery system (6).
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Footnotes
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Accepted for publication October 3, 2006.
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REFERENCES
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Abstract
Introduction
