Aortic Origin of the Left Pulmonary Artery Variant of Tetralogy of Fallot
ERWIN ROBIN, MD, FACC BORIS SILBERBERG, MD SUNILENDU N. GANGULY, KONSTANTINOS
MD
MAGNISALIS,
MD
Detroit, Michigan
A case of tetralogy of Faiiot with aortic origin of the left pulmonary artery is presented. This rare malformation should be suspected in a child with stunted growth, cyanosis, a continuous murmur over the puimonary area and a hypervascuiar left lung on chest roentgenogram. Final diagnosis depends upon cardiac catheterization and angiocardiography. During surgical correction of the tetraiogy, the left pulmonary artery can be divided from the aorta and anastomosed to the main puimonary artery.
Tetralogy of Fallot with origin of the left pulmonary artery from the ascending aorta is a rare anomaly that is usually diagnosed by angiocardiography1v2 or at autopsy. 3-5 Early recognition of this malformation is important because surgical correction may provide the only chance for survival.2 If the anomalous origin of the left pulmonary artery is not recognized before surgery, attempts to correct the tetralogy can be disastrous. 5 Our experience with a recent case provided an opportunity to review this entity. Its association with hypoplasia of the main pulmonary artery has not previously been reported. Case Report
From the Section of Cardiology and the Department of Pathology, Hutzel Hospital Medical Unit, Wayne State University, Detroit, Mich. Manuscript accepted March 27, 1974. Address for reprints: Boris Silberberg, MD, Department of Pathology, Hutzel Hospital, 432 E. Hancock, Detroit, Mich. 48201.
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A 5 month old female black infant was admitted with vomiting and diarrhea. She was slightly cyanotic; height was 56.4 cm and weight 3.6 kg (birth weight 1.8 kg). The heart rate was 120 beats/min. There was no clubbing. The peripheral pulses were normal in all four limbs. The thorax was normally shaped. No thrills were palpated. The second heart sound was single and accentuated. A grade 316 continuous murmur was heard over the pulmonary area. Routine laboratory data were within normal limits. An electrocardiogram revealed sinus tachycardia, right axis deviation and right ventricular hypertrophy (Fig. 1). A chest roentgenogram demonstrated cardiomegaly, overcirculation of the left lung and’distinct diminution of blood flow to the right lung (Fig. 2). Cardiac catheterization data are shown in Table I. A right ventriculogram revealed simultaneous opacification of both a dilated aorta and a hypoplastic right pulmonary artery. There was delayed filling of the left pulmonary artery from the aorta (Fig. 3). An aortogram disclosed origin of this artery from the ascending aorta (Fig. 4). After an uneventful hospitalization, digoxin maintenance therapy was continued. The patient remained asymptomatic until age 9 months when she was readmitted with a temperature of 104.6’ F and severe cyanosis. She died 1 hour after admission. Autopsy was performed.
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AORTIC ORIGIN OF LEFT PULMONARY
ARTERY-ROBIN
ET AL.
aVR
"i FIGURE 1. Electrocardiogram demonstrating sinus tachycardia (rate 136 beatsjmin), right axis deviation and right ventricular hypertrophy. The upright T waves over the right precordial leads suggest systolic overload of the right ventricle.
“7
TABLE
Autopsy Findings
I
Cardiac Catheterization
Gross Anatomy of the Heart The heart was slightly enlarged with a single arterial trunk at the base sweeping to the right and continuing as a left aortic arch with a normal branching pattern. Ten mm from its origin, a large branch originated on the left side of the aorta and continued as the left pulmonary artery. No ductus arteriosus was present (Fig. 5). The base of the right ventricle contained a 7 mm interventricular septal defect beneath the medial leaflet of the tricuspid valve. Anterior to this defect the right ventricular outflow tract communicated with a 3 mm vessel that proceeded posteriorly to the hilum of the right lung. The pulmonary valve consisted of a single flap of endothelium (Fig. 6 and 7). To the right and posterior to the hypoplastic right pulmonary artery a large aortic root, 18 mm in diameter, overlay the interventricular septal defect. At its origin were three leaflets of equal size with thickened rolled edges. The right sinus of Valsalva contained a prominent ostium that communicated with a single coronary artery. This vessel divided into a right and left branches. Other anatomic structures were within normal limits.
Oxygen Saturation
svc IVC RA Low
Data oxygen Content
Pressure
(%)
(vol %)
(mm f-k?)
78 80
13.6 13.9
... ...
80
13.9
Mid High RV Proximal Distal
84 82
14.6 14.3
82 85
14.3 14.7
LA LV Aorta
95 96 85
16.5 16.6 14.7
(-4) 7913
(6) 7914 80/60 (68)
Figures in parentheses indicate mean pressures. IVC = inferior vena cava; LA = left atrium; LV left ventricle; RA = right atrium; RV = right ventricle; SVC = superior vena cava.
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AORTIC ORIGIN OF LEFT PULMONARY
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FIGURE 2. Chest roentogenogram revealing cardiomegaly, prominent central left pulmonary markings and marked decrease in blood
FIGURE 3. Right ventricuiogram demonstrating simultaneous opacification of the aorta (Ao) and hypopiastic right pulmonary artery (RPA). The aortic trunk gives rise to the dilated left pulmonary artery (LPA). The origin of the right pulmonary artery is not clearly delineated.
FIGURE 4. Aortogram revealing the ectopic origin of the left pulmonary artery (LPA) from the ascending aorta (Ao).
FiGURE 5. External appearance of the heart as seen from its anterior surface. A large aortic trunk (Ao) gives rise to a dilated left pulmonary artery (L.P.A.). R.V. = right ventricle.
Additional findings were hypoplastic right lung, pneumoccocal meningitis, and fatty metamorphosis of the liver.
aorta most of the right ventricular content was ejected into the aortic trunk. The pulmonary venous blood returned normally to the left atrium and left ventricle. Since the mean left atria1 pressure was higher than the right, there must have been a left to right shunt across the atria1 septai defect. Because of the small size of this defect, the shunt was negligible as re-
flow to the rightlung.
Postnatal
Cardiac
Circulation:
(Fig. 8)
The systemic venous return to the right atrium, right ventricle and right pulmonary artery was normal. Because of the hypoplastic right pulmonary artery and overriding
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FIGURE 6. View of the heart with the right ventricle (R.V.) opened. A probe has been passed through a ventricular septal defect (V.S.D.). L.P.A. = left pulmonary artery; R.P.A. = right pulmonary artery: R.V. = right ventricie.
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FIGURE 6. Postnatal cardiac circulation. The right ventricle (R.V.) ejects its content into the hypoplastic main (M.P.A.) and right (R.P.A.) pulmonary arteries. Left ventricular blood is ejected into the aorta through a ventricular septal defect (V.S.D.). The left pulmonary artery (L.P.A.) originates from the ascending aorta. A.S.D. = atrial septal defect: I.V.C. = inferior vena cava; L.A. = left atrium: R.A. = right atrium: S.V.C. = superior vena cava.
FIGURE 7. Base of the heart as seen from the right ventricle. A probe has been passed through a ventricular septal defect (VSD). A pin has been placed into a hypoplastic right pulmonary artery (RPA). The aorta (Ao) overrides the ventricufar septal defect (VSD) and gives rise to a large left pulmonary artery (LPA).
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Current
7
case
5 mo, F
Vomiting; diarrhea; slow growth; cyanosis
Ss single and accentuated; continuous murmur; normal pulses
Cardiomegaly; increased left pulmonary vascularity
Right ventricular hypertrophy
Yes
Total correction
.
Kirkiin et al.” (1965)
Died of pneumococcal meningitis at 9 mo
doing
Total correction; well at 29 mo
Yes Right ventricular hypertrophy
Cardiomegaly; increased left pulmonary vascularity
Cyanotic episodes
S?.single and accentuated; continuous murmur
6
20 mo, F
Died during repair of tetralogy
Yes Right atrial and right ventricular hypertrophy
Normal heart size and pulmonary vascularity
Clubbing; Si single and normal intensity; continuous murmur; normal pulses
Slow growth; cyanosis
Morgan? (1972)
4 yr, F
5
et a1.j
Czarnecki (1964)
4
Loss to follow-up at 4 yr
Stillborn
... Yes
Died of bronchopneumonia at 3 mo ..
Outcome
Right ventricular hypertrophy
.
Electrocardiogram
Cardiomegaly; increased left pulmonary vascularity
murmur
Chest Roentgenogram
Murmur
1 yr, M
Mudd et al.’ (1964)
3
Continuous
Physical Srgns
Cardiac Catheterization & Angiocardiography
Slow growth; cyanosis
. .
M
Stillborn
Sikll (1952)
2
Chnical History Dyspnea, cyanosis
3mo,
Age & Sex F
Thomas (1941)
Author & Year
1
Case no.
Summary of Seven Cases
TABLE II
4
?
1
p Z
i
::
%
Z
g
2
AORTIC ORIGIN OF LEFT PULMONARY
fleeted by the absence of an increase in right atria1 oxygen saturation (Table I). The left ventricle emptied its contents through the interventricular septal defect into the aorta. The mixing of right and left ventricular blood resulted in decreased oxygen saturation in the arterial vascular bed. This was evidenced by an oxygen saturation level of 85 percent in the aorta (Table I). The left pulmonary artery was totally supplied by the aorta.
Discussion Clinical Features Enough data are available in six reported cases (and our own) to permit clinical analysis (Table II). In four female and two male patients a cardiac problem was suspected before the age of 1 year. Clinical history included retardation of growth (Cases 3, 4, and 7), cyanosis (Cases 1, 3 to 5 and 7) and cyanotic episodes (Case 5). No patient had congestive heart failure. Clubbing was present in one patient (Case 4). The second heart sound was single in three cases (Cases 4, 5 and 7), normal in intensity in one (Case 4) and accentuated in two (Cases 5 and 7). A continuous murmur was heard over the pulmonary area in four patients (Cases 1, 4, 5 and 7); peripheral pulses were normal in two (Cases 4 and 7). Chest roentgenograms revealed a hypervascular left lung in addition to cardiomegaly (Cases 3, 5 and 7). In one case pulmonary vascularity was normal (Case 4). Electrocardiograms demonstrated right atria1 hypertrophy (Case 4), and right ventricular hypertrophy (Cases 3 to 5 and 7). Angiocardiography was essential to confirm the diagnosis (Cases 3,5 and 7). In only one patient (Case 4) was the ectopic origin of the left pulmonary artery not recognized after angiographic studies. The right ventriculogram revealed simultaneous filling of the
ARTERY-ROBIN
ET AL.
right pulmonary artery and ascending aorta and late opacification of the left pulmonary artery. The ascending aortogram demonstrate the ectopic origin of the left pulmonary artery. Anamolous origin of the left pulmonary artery from the ascending aorta may occur without tetraloof gy of Fallot6T7 ard also give rise to hypervascularity the left lung. L It, in contrast to tetralogy of Fallot with origin of the left pulmonary artery from the aorta, the condition is associated with a right aortic arch and congestive heart failure. In conclusion, the clinical findings are characterized by retardation of growth, cyanosis and a continuous murmur over the pulmonary area. Chest roentgenograms reveal an enlarged heart and overcirculation of the left lung. The electrocardiogram usually reveals right ventricular hypertrophy. This combination of findings does not provide a definite diagnosis but should alert the physician to the need for cardiac catheterization and angiocardiographic studies. Surgery Successful anastomosis of the ectopic left pulmonary artery to the main pulmonary artery has been reported in cases withouts, and with2,s tetralogy of Fallot. In the latter group, the anastomosis can be performed during total correction of the tetralogy. If the anomalous pulmonary artery is not recognized before surgery, repair of the tetralogy may result in severe bleeding and death of the patient.5 Since progressive hypertensive vascular changes can develop in the left lung when the pulmonary artery arises from the aorta,7 complete surgical correction is advisable at an early age. Acknowledgment We express our gratitude to Dr. Jesse Edwards for his excellent advice in reviewing this manuscript.
References 1. Mudd JG, William VL, Riberi A: Origin of one pulmonary artery from the aorta. Am Rev Respir Dis 89:255-263, 1964 2. Morgan JR: Left pulmonary artery from ascending aorta in tetralogy of Fallot. Circulation 45:653-657, 1972 3. Thomas HW: Cardiovascular anomalies, congenital cardiac malformations. J Tech Methods 21:58-70, 1941 4. Sikl H: Unusual anomalies of arterial trunks. Main branch of pulmonary artery arising from the aorta. Cas Lek Cesk 91:13661369, 1952 5. Czarnecki SW, Hopeman AR, Child PL: Tetralogy of Fallot with aortic origin of the left pulmonary artery: angiocardiographic con-
February 1975
siderations. Dis Chest 46:97-101, 1964 Weinfraub RA, Fabian CE, Adams DF: Ectopic origin of one pulmonary artery from the ascending aorta. Radiology 86:666-676, 1966 Caudill DR, Helmsworth JA, Daoud G, et al: Anomalous origin of left pulmonary artery from ascending aorta. J Thorac Cardiovasc Surg 57:493-505, 1969 Kirklin JW, Wallace RB, McGoon DC, et al: Early and late results after intracardiac repair of tetralogy of Fallot. Ann Surg 162: 578-586, 1965
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