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Pulmonary blood flow distribution in transposition of the great arteries
Pulmonary Blood Flow Distribution in Transposition Of the Great Arteries
BERNARD0 A. VIDNE, MD* DIANA DUSZYNSKI, MD S. SUBRAMANIAN, MD, FACC Buffalo. New York
Pulmonary blood flow distribution was studied by scintillation scanning of the lungs after the infusion of iodine-131-labeled macroaggregates of human albumin before and after the Mustard operation in 53 patients with transposition of the great arteries. The patients were classified as follows: Group I (24 infants with uncomplicated transposition of the great arteries); Group II (18 patients with transposition and ventricular septal defect); and Group Ill (11 patients with transposition, ventricular septal defect and pulmonary obstruction). Before operation, 21 patients had a normal distribution of pulmonary blood flow, 10 had preferential flow to the right lung and 2 had preferential flow to the lefl lung. After operation, 19 had a normal pattern of pulmonary blood flow, 21 had preferential flow to the right lung and 3 had preferential flow to the lefl lung. The scanning studies have proved helpful in follow-up of patients to rule out recurrence of the shunt, pulmonary or systemic venous obstruction, development of pulmonary hypertension and occlusion of a palliative systemic-pulmonary shunt.
Unequal regional distribution of pulmonary blood flow associated with congenital heart disease has been reported,1-3 but we know of no single large series intended to elucidate the distribution pattern of pulmonary blood flow in transposition of the great arteries. This study was initiated prospectively to evaluate this pattern before and after hemodynamic corrective surgery in children with transposition. Pulmonary blood flow distribution can now be determined accurately and reproducibly by scintillation scanning of the lung after infusion of iodine-131-labeled macroaggregates of human albumin.4-6 Material
From the Department of Cardiovascular Surgery and Diagnostic Radiology, Buffalo Children’s Hospital, Buffalo, N. Y. Manuscript received August 1. 1975, accepted August 10, 1975. * Thoracic and Cardiovascular Surgical Department, Beilinson Medical Center, Tel-Aviv University, Israel. Address for reprints: S. Subramanian, MD, Children’s Hospital, 219 Bryant St., Buffalo, N. Y. 14222.
62
July 1976
and Methods
Fifty-three patients with transposition of the great arteries were studied within a 3 year period. In 35 patients, pre- and postoperative scintillation lung scans were obtained; in 7 lung scans were obtained only preoperatively and in 11 only postoperatively. The age of the patients ranged from 4 weeks to 35 years. Thirty-nine were less than 2 years old; only 2 were more than 12 years old. In all patients complete correction of transposition of the great arteries was performed by the intraatrial baffle technique developed by Mustard in 1963. Forty-nine patients in this series were operated on under surface-induced deep hypothermia, limited cardiopulmonary bypass and circulatory arrest.7 1311 macroaggregates of serum albumin were given intravenously into a right arm vein in a dose of 3 to 4 &i/kg body weight with the patient supine. The injections were not given while the child was crying, because the Valsalva maneuver may interfere with free passage of the dose from the vein into the thorax. A sedative and a waiting time after the needle insertion were enough to avoid this problem. Approximately 10 minutes after injection, anterior and posterior lung scans were performed with the Ohio Nuclear rectilinear scanner or scintiphotographs of both the lungs and kidneys were obtained using a Nuclear of Chicago Pho Gamma III camera equipped with a Data-Store/Playback system. Counts of the upper, middle and lower zones of each lung were registered and summated. The relative percent of the total pulmonary arterial blood flow in either lung was
The American Journal of CARDIOLOGY
Volume 38
TRANSPOSITION
ET AL.
bution could not be calculated because a systemic shunt greater than 70 percent resulted in poor concentration of radioactivity in the lung. Postoperatively, among the 22 patients studied, the distribution pattern of pulmonary blood flow was normal in 9 patients (41 percent), whereas in 9 blood flow to the right lung ranged from 56 to 65 percent and in 4 (18 percent) from 66 to 80 percent (Table 1). Group II: In 7 (50 percent) of 14 patients preoperative lung scans revealed a normal pattern of distribution of pulmonary blood flow. One of the seven patients had a pattern of pulmonary arterial hypertension, and two with a pulmonary arterial pressure greater than 40 mm Hg had a normal lung distribution pattern. Among the remaining seven patients, blood flow to the right lung ranged from 56 to 65 percent in five patients; three of these had a pattern of pulmonary arterial hypertension but only two of them had a pulmonary arterial pressure greater than 40 mm Hg. In two patients the blood flow distribution could not be evaluated because of a large systemic shunt. Postoperatiuely, 5 of 13 patients studied had a normal distribution pattern of pulmonary blood flow. Among the remaining eight patients, in four, including one with a pattern of pulmonary arterial hypertension, blood flow to the right lung ranged from 56 to 65 percent, and in two it ranged from 66 to 80 percent; in two others blood flow to the left lung ranged from 65 to 80 percent (Table I). Group III: A normal distribution pattern of pulmonary blood flow was found in 5 of 10 patients (50 percent) studied preoperatively. Among the remaining five patients blood flow to the right lung ranged from 56 to 65 percent in one and from 66 to 80 percent in two patients; in two patients the distribution pattern could not be evaluated because of a large systemic shunt and very low level of pulmonary blood flow (Fig. 1A). Postoperatiuely, five of eight patients had a normal distribution pattern of pulmonary blood flow (Fig. 1B). Of the remaining three, two had a preferential blood flow to the right lung of 60 percent and one a preferential blood flow to the left lung of 65 percent (Table I). In Group I blood flow distribution to the right lung tended to be slightly greater after operation than before
calculated by the total perfusion of one lung, divided by the sum of both lungs, multiplied by 100 ([right lung/right and left lung] X 100 = percent right lung). Each preoperative lung scan was correlated with the chest roentgenograms, cardiac catheterization data and angiocardiograms.To protect the thyroid, each patient who had not had a recent angiographic study was given Lugol’s solution orally (0.3 drops/kg body weight daily, maximal dose 15 drops) for 3 days, commencing at least 1 hour before scanning. No complications resulting from the use of the 1131-macroaggregated serum albumin were observed in any patient studied. The results in any given case were essentially reproducible at any given instance when repeated by different technicians. In this study the pattern of distribution of pulmonary blood flow was considered normal when the distribution to the right lung was 53 f 2.3 (mean f standard deviation) of the total concentration of radioactivity and the ratio distribution per unit of lung volume in the upper third was 0.43 f 0.0K8 A pattern of pulmonary arterial hypertension was considered present when the upper and lower thirds of the lung showed equal distribution of radioactivity. In 35 infants the changes in the scan patterns before and after surgery were carefully analyzed. Results Close correlation was found between the preoperative angiocardiogram and lung scan. The chest roentgenogram showed no such correlation with the angiocardiogram or lung scan. The 53 patients were classified in the following groups: Group I (24 infants with uncomplicated transposition of the great arteries); Group II (18 patients with transposition of the great arteries and ventricular septal defect); and Group III (11 patients with transposition of the great arteries, ventricular septal defect and pulmonary obstruction due either to pulmonary banding [8 patients] or valvular or infundibular stenosis [3 patients]). Group I: Preoperatiuely, 9 of 17 patients (53 percent) had a normal distribution pattern of pulmonary blood flow. One of these nine patients had a pattern of pulmonary arterial hypertension but normal pulmonary arterial pressure. Among the remaining eight patients, blood flow to the right lung ranged from 56 to 65 percent in one and from 66 to 80 percent in one; two patients manifested preferential blood flow to the left lung of 60 to 80 percent, and in four blood flow distri-
TABLE
OF GREAT ARTERIES-VIDNE
I
Pulmonary
Blood
Percent Blood Flow to Right Lung 50-55 55-65 65-80 20-50 Not celculated Total
Flow
Distribution
in 53 Patients
Group Preop 9 1 1 2 4 17
(53%) (6%) (6%) (12%) (23%)
Before
and After
Mustard
I*
Group
Procedure II*
Group
Postop
Preop
Postop
Preop
; y;
‘5 y%; 00
5 4 2 2
5 (50%) 1 (10%) 2 (20%)
4 fl&
(38%) (31%) (15.5%) (15.5%)
*Group I = transposition of the great arteries; Group septal defect and pulmonary obstruction. Postop = before operation; preop = after operation.
14 II = transposition
5 (63%) 2 (25%) ; ‘f; 2%)
13 and ventricular
July 1976
Postop
i’(iO%l
2’04%) 22
Ill*
septal defect;
10 Group
8
III = transposition,
The American Journal of CARDIOLOGY
ventricular
Volume 36
63
TRANSPOSITION
OF
GREAT
ARTERIES-VIDNE
ET
AL
400 lung scans including the present series with 1131macroaggregated albumin no complications have been found in our patients with either a right to left or left to right shunt. A good correlation between pulmonary arterial blood flow determined by the perfusion lung scan and cardiac catheterization and angiocardiographic findings was found by others5,8J2-14 and by us in this series. A normal distribution of pulmonary blood flow was found preoperatively in 21 of our patients with transposition of the great arteries whereas 10 had preferential flow to the right lung and 2 had preferential flow to the left lung. Postoperatively, 19 patients had a normal flow pattern, whereas 21 had preferential flow to the right lung and 3 had preferential flow to the left lung. When this group of patients was separated into patients with uncomplicated transposition (Group I), transposition with ventricular septal defect (Group II) and transposition with ventricular septal defect and pulmonary arterial obstruction either by pulmonary arterial banding or subpulmonary stenosis (Group III), no significant difference was found among groups in the proportion of different patterns of pulmonary blood flow distribution. In nine patients the preoperative pulmonary blood flow pattern could not be evaluated because of a large systemic shunt leading to a low level of pulmonary blood flow and consequently a very low level of lung radioactivity. No patient had postoperative evidence of a systemic shunt. Pulmonary arterial hypertension may result in an abnormal distribution of radioactivity in the lung field.5 However, we found no close correlation between the classic pattern of pulmonary arterial hypertension and pulmonary arterial pressure. Pulmonary
operation (Fig, 2). In Group II postoperative blood flow distribution to the right lung ranged widely, from 20 to 80 percent (Fig. 3), and in Group III four of five patients had normal values postoperatively (Fig. 4). Discussion The rate of accumulation of a substance in any region of the body is directly proportional to the blood flow to the region provided the substance is completely removed from the blood and is not metabolized during the period of observation. To evaluate the pattern of distribution of pulmonary blood flow in patients with transposition of the great arteries before and after complete correction, the distribution of radioactivity in the scintillation lung scan after injection of 1131macroaggregated albumin was utilized. In more than
A . .
.
.-
TGA
tGROlJP I)
RIGHT LUNG % a0
q
-0
PRE OP
FIGURE 1. Lung scans in a patient with transposition of the great arteries, ventricular septal defect and pulmonary stenosis (Group III). A, preoperative, showing a high level of radioactivity in the heart and almost no radioactivity in the lung field. B, postoperative, showing a normal lung scan.
64
July 1976
The American
Journal
of CARDIOLOGY
Volume
PI% OP
FIGURE 2. Group I. Pre- and pos,toperative pulmonary blood flow distribution in nine patients with transposition of the great arteries who underwent Mustard’s procedure for correction.
36
TRANSPOSITION
TGA +VSD
OF
GREAT
TGA + VSD + PS
(GROUP II I
RIGHTLUNG
ARTERIES-VIDNE
ET
AL.
( GROUP III 1
RIGHTLUNG
%
% so 0
L-.-O
PRE OP
rnkis;TOP
FIGURE 3. Group II. Pre- and postoperative pulmonary blood flow distribution in 11 patients with transposition of the great arteries and ventricular septal defect who underwent Mustard’s procedure for complete correction.
venous hypertension, on the other hand, causes a characteristic redistribution of pulmonary blood flow and abnormal perfusion scans.5 Therefore, the postoperative lung scans in the diagnosis of venous obstruction after Mustard’s procedure should be useful. No patient in our series had signs of pulmonary venous obstruction in the postoperative lung scan. Correlation of chest roentgenogram, lung scan and angiocardiogram: Muster et al.l* reported correlation of the chest roentgenogram, lung scan and angiocardiogram in five infants with diminished left pulmonary flow in transposition of the great arteries not suspected from the chest roentgenogram before angiography. Lung scans in these five patients corroborated the angiographic finding, showing a mean uptake for the group of 22 percent in the left and 78 percent in the right lung. Muster et al.14 considered two mechanisms for this unequal distribution of pulmonary blood flow: (1) The existence in transposition of an unusual angulation of the right and left pulmonary arteries at their junction with the main pulmonary artery may result in preferential flow to the right pulmonary artery and (2) a Coanda effect generated in transposition by accelerated blood flow across the left ventricular outflow tract may favor bloodstreaming along the right wall of the pulmonary artery. In our series, we also found no correlation between the chest roentgenogram and either the
P;E op
&OP
FIGURE 4. Group Ill. Pre- and postoperative pulmonary blood flow distribution in five patients with transposition of the great arteries and ventricular septal defect and pulmonary obstruction who underwent Mustard’s procedure for complete correction.
lung scan or angiocardiogram, but a close correlation between the lung scan and angiocardiogram. The inability of the chest roentgenogram to show the unequal distribution of pulmonary blood flow could be explained by the large shunt and low pulmonary flow level present in our patients. Nevertheless, as a screening procedure and for a serial study of the effects of surgical intervention, the lung scans provide physiologic and anatomic information. Clinical applications: The atraumatic and noninvasive nature of this examination deserves special emphasis in the pediatric age group. This procedure can easily be performed on an outpatient basis and therefore removes from the patient, parents and physicians, psychologic burdens associated with hospitalization for collection of follow-up data on a child who is otherwise doing well. We have found this procedure to be helpful in follow-up studies to rule out (1) recurrence of a systemic shunt of transposition after correction or (2) possible development of pulmonary venous hypertension. This method is technically simple, without risk, easily applicable to large numbers of patients and provides important postoperative follow-up information. All patients in our institution with cyanotic congenital heart disease are now studied preoperatively by scintillation lung scan.
References 1. Whitiey SE, Rudhe V, Herzenberg H: Decreased left lung vascu-
larity in congenital left to right shunts. Acta Radiologica 1: 1125-l 131, 1963 2. Fleming HA: Differential function in atriil septal defect. Circulation
19:856-862, 1959 3. Garfunkei JM, Kirkpatrick JA: Decreased vascularity of the left lung and unequal aeration of the lungs as a manifestation of patent ductus arteriosus. Am J Roentgen01 89:1012-1016, 1963
July 1976
The American Journal of CARDIOLOGY
Volume 36
65
TRANSPOSITION
OF GREAT ARTERIES-VIDNE
ET AL.
4. Lopez-Majano
5.
6.
7.
8.
9.
66
V, Chernick V, Wagner HN Jr, et al: Comparison of radioisotope scanning and differential oxygen uptake of the lungs. Radiology 83:697-698, 1964 Friedman WF, Braunwald E: Alteration in regional pulmonary blood flow in mitral valve disease studied by radioisotope scanning: simple nontraumatic technique for estimation of left atrial pressure. Circulation 34:363-376, 1966 Tauxe WN, Burcheii HB, Chaapei DW, et al: Quantitating the effect of gravity on lung scans of macroaggregates of albumin li3’. J Appl Physiol 21:1381-1386, 1966 Subramanian S, Wagner H: Correction of transposition of the great arteries under surface induced deep hypothermia. Ann Thorac Surg 16:391-401, 1973 Friedman WF, Braunwald E, Morrow AG: Alterations in regional pulmonary blood flow in patients with congenital heart disease studied by radioisotope scanning. Circulation 37:747-758, 1968 Tow DE, Wagner HN, Lopez-Majano V et al: Validity of measuring
July 1976
The American Journal of CARDIOLOGY
Volume 38
regional pulmonary arterial blood flow with macroaggregates of human serum albumin. Am J Roentgen01 96:664-676, 1966 10. Wagner HN, Sabiston DC, Tio M, et al: Regional pulmonary blood flow in man by radioisotope scanning. JAMA 187:601-603, 1964 11 Tong ECK, Liu L, Potter FIT, et al: Macroaggregated RISA lung scan in congenital heart disease. Radiology 106:585-592. 1973 12 Moser KM, Tisi GM, Rhodes PG, et al: Correlation of lung photoscans with pulmonary angiography in pulmonary embolism. Am J Cardiol 18:810-820, 1966 13. Stjernholm MR, Landis GA, Macus Fi, et al: Perfusion and ventilation radioisotope lung scans in stenosis of the pulmonary arteries and their branches. Am Heart J 78:37-42, 1969 14. Muster A, Paul M, Levin D, et al: Diminished left pulmonary blood flow in transposition of the great arteries. Am J Cardiol (abstr). 31:150, 1973
BERNARD0 A. VIDNE, MD* DIANA DUSZYNSKI, MD S. SUBRAMANIAN, MD, FACC Buffalo. New York
Pulmonary blood flow distribution was studied by scintillation scanning of the lungs after the infusion of iodine-131-labeled macroaggregates of human albumin before and after the Mustard operation in 53 patients with transposition of the great arteries. The patients were classified as follows: Group I (24 infants with uncomplicated transposition of the great arteries); Group II (18 patients with transposition and ventricular septal defect); and Group Ill (11 patients with transposition, ventricular septal defect and pulmonary obstruction). Before operation, 21 patients had a normal distribution of pulmonary blood flow, 10 had preferential flow to the right lung and 2 had preferential flow to the lefl lung. After operation, 19 had a normal pattern of pulmonary blood flow, 21 had preferential flow to the right lung and 3 had preferential flow to the lefl lung. The scanning studies have proved helpful in follow-up of patients to rule out recurrence of the shunt, pulmonary or systemic venous obstruction, development of pulmonary hypertension and occlusion of a palliative systemic-pulmonary shunt.
Unequal regional distribution of pulmonary blood flow associated with congenital heart disease has been reported,1-3 but we know of no single large series intended to elucidate the distribution pattern of pulmonary blood flow in transposition of the great arteries. This study was initiated prospectively to evaluate this pattern before and after hemodynamic corrective surgery in children with transposition. Pulmonary blood flow distribution can now be determined accurately and reproducibly by scintillation scanning of the lung after infusion of iodine-131-labeled macroaggregates of human albumin.4-6 Material
From the Department of Cardiovascular Surgery and Diagnostic Radiology, Buffalo Children’s Hospital, Buffalo, N. Y. Manuscript received August 1. 1975, accepted August 10, 1975. * Thoracic and Cardiovascular Surgical Department, Beilinson Medical Center, Tel-Aviv University, Israel. Address for reprints: S. Subramanian, MD, Children’s Hospital, 219 Bryant St., Buffalo, N. Y. 14222.
62
July 1976
and Methods
Fifty-three patients with transposition of the great arteries were studied within a 3 year period. In 35 patients, pre- and postoperative scintillation lung scans were obtained; in 7 lung scans were obtained only preoperatively and in 11 only postoperatively. The age of the patients ranged from 4 weeks to 35 years. Thirty-nine were less than 2 years old; only 2 were more than 12 years old. In all patients complete correction of transposition of the great arteries was performed by the intraatrial baffle technique developed by Mustard in 1963. Forty-nine patients in this series were operated on under surface-induced deep hypothermia, limited cardiopulmonary bypass and circulatory arrest.7 1311 macroaggregates of serum albumin were given intravenously into a right arm vein in a dose of 3 to 4 &i/kg body weight with the patient supine. The injections were not given while the child was crying, because the Valsalva maneuver may interfere with free passage of the dose from the vein into the thorax. A sedative and a waiting time after the needle insertion were enough to avoid this problem. Approximately 10 minutes after injection, anterior and posterior lung scans were performed with the Ohio Nuclear rectilinear scanner or scintiphotographs of both the lungs and kidneys were obtained using a Nuclear of Chicago Pho Gamma III camera equipped with a Data-Store/Playback system. Counts of the upper, middle and lower zones of each lung were registered and summated. The relative percent of the total pulmonary arterial blood flow in either lung was
The American Journal of CARDIOLOGY
Volume 38
TRANSPOSITION
ET AL.
bution could not be calculated because a systemic shunt greater than 70 percent resulted in poor concentration of radioactivity in the lung. Postoperatively, among the 22 patients studied, the distribution pattern of pulmonary blood flow was normal in 9 patients (41 percent), whereas in 9 blood flow to the right lung ranged from 56 to 65 percent and in 4 (18 percent) from 66 to 80 percent (Table 1). Group II: In 7 (50 percent) of 14 patients preoperative lung scans revealed a normal pattern of distribution of pulmonary blood flow. One of the seven patients had a pattern of pulmonary arterial hypertension, and two with a pulmonary arterial pressure greater than 40 mm Hg had a normal lung distribution pattern. Among the remaining seven patients, blood flow to the right lung ranged from 56 to 65 percent in five patients; three of these had a pattern of pulmonary arterial hypertension but only two of them had a pulmonary arterial pressure greater than 40 mm Hg. In two patients the blood flow distribution could not be evaluated because of a large systemic shunt. Postoperatiuely, 5 of 13 patients studied had a normal distribution pattern of pulmonary blood flow. Among the remaining eight patients, in four, including one with a pattern of pulmonary arterial hypertension, blood flow to the right lung ranged from 56 to 65 percent, and in two it ranged from 66 to 80 percent; in two others blood flow to the left lung ranged from 65 to 80 percent (Table I). Group III: A normal distribution pattern of pulmonary blood flow was found in 5 of 10 patients (50 percent) studied preoperatively. Among the remaining five patients blood flow to the right lung ranged from 56 to 65 percent in one and from 66 to 80 percent in two patients; in two patients the distribution pattern could not be evaluated because of a large systemic shunt and very low level of pulmonary blood flow (Fig. 1A). Postoperatiuely, five of eight patients had a normal distribution pattern of pulmonary blood flow (Fig. 1B). Of the remaining three, two had a preferential blood flow to the right lung of 60 percent and one a preferential blood flow to the left lung of 65 percent (Table I). In Group I blood flow distribution to the right lung tended to be slightly greater after operation than before
calculated by the total perfusion of one lung, divided by the sum of both lungs, multiplied by 100 ([right lung/right and left lung] X 100 = percent right lung). Each preoperative lung scan was correlated with the chest roentgenograms, cardiac catheterization data and angiocardiograms.To protect the thyroid, each patient who had not had a recent angiographic study was given Lugol’s solution orally (0.3 drops/kg body weight daily, maximal dose 15 drops) for 3 days, commencing at least 1 hour before scanning. No complications resulting from the use of the 1131-macroaggregated serum albumin were observed in any patient studied. The results in any given case were essentially reproducible at any given instance when repeated by different technicians. In this study the pattern of distribution of pulmonary blood flow was considered normal when the distribution to the right lung was 53 f 2.3 (mean f standard deviation) of the total concentration of radioactivity and the ratio distribution per unit of lung volume in the upper third was 0.43 f 0.0K8 A pattern of pulmonary arterial hypertension was considered present when the upper and lower thirds of the lung showed equal distribution of radioactivity. In 35 infants the changes in the scan patterns before and after surgery were carefully analyzed. Results Close correlation was found between the preoperative angiocardiogram and lung scan. The chest roentgenogram showed no such correlation with the angiocardiogram or lung scan. The 53 patients were classified in the following groups: Group I (24 infants with uncomplicated transposition of the great arteries); Group II (18 patients with transposition of the great arteries and ventricular septal defect); and Group III (11 patients with transposition of the great arteries, ventricular septal defect and pulmonary obstruction due either to pulmonary banding [8 patients] or valvular or infundibular stenosis [3 patients]). Group I: Preoperatiuely, 9 of 17 patients (53 percent) had a normal distribution pattern of pulmonary blood flow. One of these nine patients had a pattern of pulmonary arterial hypertension but normal pulmonary arterial pressure. Among the remaining eight patients, blood flow to the right lung ranged from 56 to 65 percent in one and from 66 to 80 percent in one; two patients manifested preferential blood flow to the left lung of 60 to 80 percent, and in four blood flow distri-
TABLE
OF GREAT ARTERIES-VIDNE
I
Pulmonary
Blood
Percent Blood Flow to Right Lung 50-55 55-65 65-80 20-50 Not celculated Total
Flow
Distribution
in 53 Patients
Group Preop 9 1 1 2 4 17
(53%) (6%) (6%) (12%) (23%)
Before
and After
Mustard
I*
Group
Procedure II*
Group
Postop
Preop
Postop
Preop
; y;
‘5 y%; 00
5 4 2 2
5 (50%) 1 (10%) 2 (20%)
4 fl&
(38%) (31%) (15.5%) (15.5%)
*Group I = transposition of the great arteries; Group septal defect and pulmonary obstruction. Postop = before operation; preop = after operation.
14 II = transposition
5 (63%) 2 (25%) ; ‘f; 2%)
13 and ventricular
July 1976
Postop
i’(iO%l
2’04%) 22
Ill*
septal defect;
10 Group
8
III = transposition,
The American Journal of CARDIOLOGY
ventricular
Volume 36
63
TRANSPOSITION
OF
GREAT
ARTERIES-VIDNE
ET
AL
400 lung scans including the present series with 1131macroaggregated albumin no complications have been found in our patients with either a right to left or left to right shunt. A good correlation between pulmonary arterial blood flow determined by the perfusion lung scan and cardiac catheterization and angiocardiographic findings was found by others5,8J2-14 and by us in this series. A normal distribution of pulmonary blood flow was found preoperatively in 21 of our patients with transposition of the great arteries whereas 10 had preferential flow to the right lung and 2 had preferential flow to the left lung. Postoperatively, 19 patients had a normal flow pattern, whereas 21 had preferential flow to the right lung and 3 had preferential flow to the left lung. When this group of patients was separated into patients with uncomplicated transposition (Group I), transposition with ventricular septal defect (Group II) and transposition with ventricular septal defect and pulmonary arterial obstruction either by pulmonary arterial banding or subpulmonary stenosis (Group III), no significant difference was found among groups in the proportion of different patterns of pulmonary blood flow distribution. In nine patients the preoperative pulmonary blood flow pattern could not be evaluated because of a large systemic shunt leading to a low level of pulmonary blood flow and consequently a very low level of lung radioactivity. No patient had postoperative evidence of a systemic shunt. Pulmonary arterial hypertension may result in an abnormal distribution of radioactivity in the lung field.5 However, we found no close correlation between the classic pattern of pulmonary arterial hypertension and pulmonary arterial pressure. Pulmonary
operation (Fig, 2). In Group II postoperative blood flow distribution to the right lung ranged widely, from 20 to 80 percent (Fig. 3), and in Group III four of five patients had normal values postoperatively (Fig. 4). Discussion The rate of accumulation of a substance in any region of the body is directly proportional to the blood flow to the region provided the substance is completely removed from the blood and is not metabolized during the period of observation. To evaluate the pattern of distribution of pulmonary blood flow in patients with transposition of the great arteries before and after complete correction, the distribution of radioactivity in the scintillation lung scan after injection of 1131macroaggregated albumin was utilized. In more than
A . .
.
.-
TGA
tGROlJP I)
RIGHT LUNG % a0
q
-0
PRE OP
FIGURE 1. Lung scans in a patient with transposition of the great arteries, ventricular septal defect and pulmonary stenosis (Group III). A, preoperative, showing a high level of radioactivity in the heart and almost no radioactivity in the lung field. B, postoperative, showing a normal lung scan.
64
July 1976
The American
Journal
of CARDIOLOGY
Volume
PI% OP
FIGURE 2. Group I. Pre- and pos,toperative pulmonary blood flow distribution in nine patients with transposition of the great arteries who underwent Mustard’s procedure for correction.
36
TRANSPOSITION
TGA +VSD
OF
GREAT
TGA + VSD + PS
(GROUP II I
RIGHTLUNG
ARTERIES-VIDNE
ET
AL.
( GROUP III 1
RIGHTLUNG
%
% so 0
L-.-O
PRE OP
rnkis;TOP
FIGURE 3. Group II. Pre- and postoperative pulmonary blood flow distribution in 11 patients with transposition of the great arteries and ventricular septal defect who underwent Mustard’s procedure for complete correction.
venous hypertension, on the other hand, causes a characteristic redistribution of pulmonary blood flow and abnormal perfusion scans.5 Therefore, the postoperative lung scans in the diagnosis of venous obstruction after Mustard’s procedure should be useful. No patient in our series had signs of pulmonary venous obstruction in the postoperative lung scan. Correlation of chest roentgenogram, lung scan and angiocardiogram: Muster et al.l* reported correlation of the chest roentgenogram, lung scan and angiocardiogram in five infants with diminished left pulmonary flow in transposition of the great arteries not suspected from the chest roentgenogram before angiography. Lung scans in these five patients corroborated the angiographic finding, showing a mean uptake for the group of 22 percent in the left and 78 percent in the right lung. Muster et al.14 considered two mechanisms for this unequal distribution of pulmonary blood flow: (1) The existence in transposition of an unusual angulation of the right and left pulmonary arteries at their junction with the main pulmonary artery may result in preferential flow to the right pulmonary artery and (2) a Coanda effect generated in transposition by accelerated blood flow across the left ventricular outflow tract may favor bloodstreaming along the right wall of the pulmonary artery. In our series, we also found no correlation between the chest roentgenogram and either the
P;E op
&OP
FIGURE 4. Group Ill. Pre- and postoperative pulmonary blood flow distribution in five patients with transposition of the great arteries and ventricular septal defect and pulmonary obstruction who underwent Mustard’s procedure for complete correction.
lung scan or angiocardiogram, but a close correlation between the lung scan and angiocardiogram. The inability of the chest roentgenogram to show the unequal distribution of pulmonary blood flow could be explained by the large shunt and low pulmonary flow level present in our patients. Nevertheless, as a screening procedure and for a serial study of the effects of surgical intervention, the lung scans provide physiologic and anatomic information. Clinical applications: The atraumatic and noninvasive nature of this examination deserves special emphasis in the pediatric age group. This procedure can easily be performed on an outpatient basis and therefore removes from the patient, parents and physicians, psychologic burdens associated with hospitalization for collection of follow-up data on a child who is otherwise doing well. We have found this procedure to be helpful in follow-up studies to rule out (1) recurrence of a systemic shunt of transposition after correction or (2) possible development of pulmonary venous hypertension. This method is technically simple, without risk, easily applicable to large numbers of patients and provides important postoperative follow-up information. All patients in our institution with cyanotic congenital heart disease are now studied preoperatively by scintillation lung scan.
References 1. Whitiey SE, Rudhe V, Herzenberg H: Decreased left lung vascu-
larity in congenital left to right shunts. Acta Radiologica 1: 1125-l 131, 1963 2. Fleming HA: Differential function in atriil septal defect. Circulation
19:856-862, 1959 3. Garfunkei JM, Kirkpatrick JA: Decreased vascularity of the left lung and unequal aeration of the lungs as a manifestation of patent ductus arteriosus. Am J Roentgen01 89:1012-1016, 1963
July 1976
The American Journal of CARDIOLOGY
Volume 36
65
TRANSPOSITION
OF GREAT ARTERIES-VIDNE
ET AL.
4. Lopez-Majano
5.
6.
7.
8.
9.
66
V, Chernick V, Wagner HN Jr, et al: Comparison of radioisotope scanning and differential oxygen uptake of the lungs. Radiology 83:697-698, 1964 Friedman WF, Braunwald E: Alteration in regional pulmonary blood flow in mitral valve disease studied by radioisotope scanning: simple nontraumatic technique for estimation of left atrial pressure. Circulation 34:363-376, 1966 Tauxe WN, Burcheii HB, Chaapei DW, et al: Quantitating the effect of gravity on lung scans of macroaggregates of albumin li3’. J Appl Physiol 21:1381-1386, 1966 Subramanian S, Wagner H: Correction of transposition of the great arteries under surface induced deep hypothermia. Ann Thorac Surg 16:391-401, 1973 Friedman WF, Braunwald E, Morrow AG: Alterations in regional pulmonary blood flow in patients with congenital heart disease studied by radioisotope scanning. Circulation 37:747-758, 1968 Tow DE, Wagner HN, Lopez-Majano V et al: Validity of measuring
July 1976
The American Journal of CARDIOLOGY
Volume 38
regional pulmonary arterial blood flow with macroaggregates of human serum albumin. Am J Roentgen01 96:664-676, 1966 10. Wagner HN, Sabiston DC, Tio M, et al: Regional pulmonary blood flow in man by radioisotope scanning. JAMA 187:601-603, 1964 11 Tong ECK, Liu L, Potter FIT, et al: Macroaggregated RISA lung scan in congenital heart disease. Radiology 106:585-592. 1973 12 Moser KM, Tisi GM, Rhodes PG, et al: Correlation of lung photoscans with pulmonary angiography in pulmonary embolism. Am J Cardiol 18:810-820, 1966 13. Stjernholm MR, Landis GA, Macus Fi, et al: Perfusion and ventilation radioisotope lung scans in stenosis of the pulmonary arteries and their branches. Am Heart J 78:37-42, 1969 14. Muster A, Paul M, Levin D, et al: Diminished left pulmonary blood flow in transposition of the great arteries. Am J Cardiol (abstr). 31:150, 1973