Aorticopulmonary septal defect and interrupted aortic arch: A diagnostic challenge

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Aorticopulmonary Septal Defect and Interrupted Aortic Arch: A Diagnostic Challenge

ELIZABETH A. FISHER, MD IRA W. DuBROW, MD FRIEDRICH A. 0. ECKNER, MD ALOIS R. HASTREITER, MD, FACC Chicago, Illinois

A report of a rare case of aorticopulmonary septal defect and interrupted aortic arch Cspresented with cardiac catheterization, cineangiocardiographic and autopsy findings. Emphasis is placed on the masking of the Interrupted arch by !he presence of an aorticopulmonary septal defect and patent ductus arterlosus.

Aorticopulmonary septal defect is a rare malformation and when found in association with interrupted aortic arch it is even more unusual. Only four cases with this combination of defects have been previously reported,1-4 and cardiac catheterization data are available in only one.4 This paper describes a fifth such case, with cardiac catheterization data, and draws attention to the diagnostic problems inherent in this anatomic complex. Case Report

From the Division of Pediatric Cardiology, University of Illinois Hospital and Abraham Lincoln School of Medicine, Chicago, Ill. This study was supported in part by Grant 2-44-33-66-3-14 from the University of Illinois Foundation, Goodenberger Medical Research. Manuscript accepted January 3, 1974. Address ‘for reprints: Alois R. Hastrefter, MD, Department of Pediatrics, University of Illinois Hospital, 840 South Wood St., Chicago. III.

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A 6 week old male infant was referred to the University of Illinois Hospital because of progressive wheezing and respiratory distress of 2 weeks’ duration. He was the 3 kg product of an uneventful gestation and delivery of a 26 year old primigravida. Hemoglobin was 9.4 g/100 ml on admission. On physical examination, he was markedly dyspneic and slightly cyanotic. No differential cyanosis was noted. The heart rate was 180 beats/min and the respiratory rate 80/min. There were expiratory wheezes over both lung fields but no rales. The peripheral pulses were all quite weak. Blood pressures were not obtained. The precordium was hyperactive, and the heart was enlarged. There was a parasternal impulse. The second heart sound was loud and single. The first heart sound was soft, and there was a gallop sound at the lower left sternal border. The liver was palpable 3 cm below the right costal margin, The chest roentgenogram demonstrated cardiomegaly and increased vascular markings. The electrocardiogram demonstrated a frontal QRS axis of +30° and combined ventricular and atria1 hypertrophy (Fig. 1). After treatment with digoxin and diuretic agents, his condition did not improve significantly, and cardiac catheterization was performed. The cardiac catheterization findings are listed in Tables I and II. A left to right shunt was demonstrated at the pulmonary arterial level. The venous catheter, in addition to its usual course, went from the proximal main pulmonary artery across the patent ductus arteriosus to the right-sided thoracic aorta. The arterial catheter course was from the left-sided abdominal aorta to the thoracic aorta across what was believed to be the aortic isthmus to the ascending aorta (Fig. 2). The pressures in the ascending aorta, descending aorta and main pulmonary artery were essentially identical (Fig. 3). There was no lag between the ascending and descending aorta. Selective angiography demonstrated the following: (1) Dye injection into the ascending aorta (Fig. 2) revealed simultaneous filling of the main pulmonary artery and ascending aorta. The aortic isthmus was not visualized. (2) During injection into the main pulmonary artery fFig. 4), the ascending aorta and main pulmonary artery opacified simultaneously. The origin of the descending aorta was obscured by the dilated pulmonary artery and the large shunt. Two separate semilunar valves were clearly demonstrated, thereby ruling out truncus arteriosus. After slow blood transfusion with packed cells, the infant underwent surgical exploration of the aortic arch and closure of the aorticopulmonary septal defect. He died during the procedure.

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I

II

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aVR

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V4R

FIGURE 1. Electrocardiogram.

VI

v2

v4

vs

v6

v7

FtGURE 2. Biplane frontal (A) and lateral (B) cineangiocardiograms with injection of contrast medium into the ascending aorta (Asc Ao). The arterial catheter (cath) appears to cross an intact aortic arch to enter the ascending aorta. The ascending aorta and main pulmonary artery opacify simultaneously. Three branches arise from the ascending aorta. Inn = innominate artery: LC = left carotid artery; LPA = left pulmonary artery; LS = left subclavian artery: PA = pulmonary artery; RPA = right pulmonary artery.

TABLE

I

Cardiac Catheterization

Data O2Saturation

Site svc IVC RA RV MPA Asc Ao LPA LLPV LA LV Asc Ao Desc Ao

(%) 54 50 53 64 ...

... 77 a7 91 ... 91 ...

Pressure*

TABLE

(mm Hg)

II

Hemodynamic

... ... a 5, v 7, m 2.5 7513 75143 m 60 77138 1 + 70127 m 47

Calculations

On capacity (vol 96) O2 consumption (ml/min per m*) (assumed) EQp (liters/min per rn’) Qp (liters/min per m2) Qs (liters/min per m*)

...

QPIQs

d 15, v 21. m 10 90/9 90/47 m 59 t 87143 m 58 1

*All pressures represent an average of lOconsecutive beats. + Simultaneous pressures. d = a wave; Asc Ao= ascending aorta; Desc Ao = descending aorta: IVC = inferior vena cava; LA = left atrium; LLPV = lower left pulmonary vein; LPA = left pulmonary artery; LV = left ventricle; m = mean; MPA = main pulmonary artery; RA = right atrium: RV = right ventricle; SVC = superior vena cava; v = v wave.

L-R shunt (liters/min per m*> R-L shunt (liters/min per m2) PVR (liters/min. mm Hg. m2) SVR (liters/min.mm Hg.m2) PVR/SVR

10.6 130.0 3.3 a.9 3.3 2.7 5.6 ... 4.2 18.9 0.22

For calculation of Qp, LPA and LA samples were used. The latterreflected mixed pulmonary venous return. EQp = effective pulmonary blood flow: L-R = left to right; PVR = pulmonary vascular resistance; Qp = pulmonary blood flow; Qs = systemic blood flow; R-L = right to left; SVR = systemic vascular resistance; . . . = not calculated.

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FIGURE 3. Simultaneous pressure recordings in the ascending (Asc Ao) and descending (Desc Ao) aorta (A) and in the ascending aorta and main pulmonary artery (MPA) (B). The electrocardiogram is shown at top and the pressure scale in millimeters of mercury at left. Despite the respiratory variation. pressures in the ascending aorta, descending aorta and main pulmonary artery are equal.

FIGURE 4.‘Bipkoe frootal (k) and laterai (B) cineangiocardiograms with injection of contrast medium into the main pulmonary artery (MPA). Again, Sirputtaneous filling of th%.aScending aorta (Asc Ao) and main pulmonary artery is demonstrated. The descending aorta (Desc Ao) is well seen, but the area of the aortic arch is obscured by the main pulmonary artery. In 8, two separate semilunar valves are seen (arrows). AV = aortic valve; LPA = left pulmooaiy artery: PV = pulmonic valve: RPA = right pulmonary artery.

At autopsy, examination of the great arteries showed a normally placed ascending aorta continuous with the three major branches (Fig. 5). No connection was found between the ascending and right descending thoracic aorta. The main pulmonary artery was quite large and gave rise to right and left pulmonary arteries and the descending aorta, the latter’ by way of a large patent ductus arteriosus. A large aqrticopulmonary septal defect had been surgically closed by direct suture. The ventricular septum was intact. Discussion

Three of the four previously reported cases ticopulmonary septal defect with interruption aortic arch were diagnosed at autopsy.1-3 The case* was diagnosed at cardiac catheterization. the arterial catheterization was performed by

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the right brachial artery, no confusion resulted from the catheter course. In our case, the arterial catheter was introduced through the femoral artery and advanced easily into the ascending aorta, taking a course consistent with an intact aortic arch. Because of severe pulmonary hypertension, pressures were identical in the ascending and descending aorta and pulmonary artery, thus giving no clue to the presence of aortic obstruction. Although the cineangiogram obtained after main pulmonary arterial injection (frontal view) was highly suggestive of interruption of the aortic arch with filling of the descending aorta from the pulmonary artery, it was nondiagnostic because of the large shunt through the aorticopulmonary septal defect. Deter-

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FIGURE 5 (leftj. View of opened left ventricle (LV). Note the intact ventricular septum. The aorta (Ao) is opened and the vertical slit indicated is the site of repair of tha aortkqulmonary septal defect (APSD).Three branches arise from the aorta, the innominate (Inn), the left carotid (LC) (seen on end) and the left subclavian (LS) artery. The main pulmonary artery (MPA) has been bisected at autopsy. The patent ductus arteriosus (PDA) and a short segment of descending aorta are seen to the right of the main pulmonary artery. FIGURE 6 (top). Artist’s rendering of anteroposterior (AP) and lateral views of the great arteries illustrating the arterial catheter course. Although the catheter position seems to demonstrate an intact aortic arch, the catheter in fact fast passed from the descending aorta (Desc Ao) through a patent ductus arteriosus into the main pulmonary artery and from there across the aorticopulmonary septal defect into the ascending aorta (Asc Ao).

mination of aortic saturation below the interruption would have been of value to demonstrate the right to left shunt through the aorticopulmonary septal defect and the ductus arteriosus. However, in view of the severe pulmonary hypertension, this finding would not have been diagnostic of interruption of the aortic arch. Only upon examining the autopsy specimen did it become obvious that the arterial catheter had first passed through the patent ductus arteriosus into the main pulmonary artery, and then through the aorticopulmonary septal defect into the ascend-

ing aorta (Fig. 6). In the absence of either the patent ductus arteriosus or the aorticopulmonary septal defect, or had the arterial catheterization been done from the arm, the diagnosis would have been more easily made at catheterization. This case is important for two reasons: (1)It is the fifth reported case of aorticopulmonary septal defect and interrupted aortic arch. (2) It demonstrates the masking of an interrupted aortic arch by an aorticopulmonary septal defect and patent ductus arteriosus.

References 1. Blake HA, Manlon WC, Spencer FC: Atresia or absence of aortic isthmus. J Thorac Cardiovasc Surg 43:607-614. 1962 2. Mehrlzl A, Morrlsh HF: Interruption of aortic arch. Bull Johns Hopkins Hosp 111:127-142, 1962 3. Watson H: Pediatric Cardiology. St. Louis, CV Mosby, 1968, p

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224 4. ChiemmoqkoMp P, Moukbr PV, Camels M: lnterruption of the aortic arch wlth aortico-pulmonary septal defect and intact ventricular septum in a teenage girl. Chest 60: 324-327.1971

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