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Banding of the pulmonary trunk in persistent truncus arteriosus
Banding of the pulmonary trunk in persistent truncus arteriosus Rapid subsequent development of inadequate pulmonary blood flow Sidney Friedman, M.D., and Robert E. Braitman, B.A., Philadelphia, Pa.
Rrsistent truncus arteriosus is an uncommon variety of cyanotic congenital cardiac disease which is recognized to have a poor prognosis. In untreated cases, survival is rare beyond the age of six months." 2 The usual cause of death is congestive heart failure; excessive pulmonary blood flow and pulmonary hypertension contribute. In 1968, McGoon, Rastelli, and Ongley" described a surgical procedure for physiologic and anatomic correction of persistent truncus arteriosus, applicable in patients with undamaged pulmonary vasculature who are beyond infancy. The procedure involves the construction of a new pulmonary outflow tract by insertion of an aortic homograft and valve into the superior portion of the right ventricle, closure of the ventricular septal defect in a manner to produce continuity between the left ventricle and truncus arteriosus, and connection of the pulmonary artery branches to the new main pulmonary artery represented by the aortic homograft.
From the Division of Cardiology, The Children's Hospital of Philadelphia, and the Department of Pediatrics, School of Medicine. University of Pennsylvania, Philadelphia, Pa. 19146. Received for publication June 7, 1973.
The youngest patient successfully treated by this method was 3 years of age'; older and larger subjects are obviously more favorable candidates. In 1964 banding of the pulmonary trunk or the individual pulmonary arteries was reported to control congestive heart failure in patients with persistent truncus arteriosus." Restriction of pulmonary blood flow may serve not only to provide palliation until a favorable age and size for surgical correction is reached, but also to protect the pulmonary vascular bed from pulmonary vascular occlusive changes in the interim. The purpose of this report is to describe an infant with persistent truncus arteriosus who was in intractable congestive heart failure. Palliation by pulmonary truncal banding at the age of 3 weeks was successful, but the child developed signs of grossly inadequate pulmonary blood flow only 2 years thereafter. Further surgical treatment was necessary in order to increase pulmonary blood flow and was successfully provided by the creation of a systemic artery-pulmonary artery anastomosis. This unusual sequence of events in the surgical treatment of persistent truncus arteriosus has not been previously described.
799
800
Friedman and Braitman
Fig. 1. Twelve-lead electrocardiogram recorded from a 3-week-old infant with persistent truncus arteriosus (type I) . The tracing. recorded prior to banding of the pulmonary trunk . shows left ventricular hypertrophy.
Case report K. K., a white boy, was born on March 31, 1970, following an uncomplicated term pregnancy. Apgar scores were 8 at 1 minute and 10 at 5 minutes. The first 3 days of life were uneventful. Rapid respirations (72 breaths per minute), dyspnea, and circumoral cyanosis were noted on the fourth day of life. Chest roentgenograms at this time showed card iac enlargement and accentuation of the pulmonary vasculature. Digitalization produced little improvement and the infant was transferred to The Children's Hospital of Philadelphia on April 10, 1970, for study and treatment of cyanotic congenital heart disease. Physical examination on admission revealed a well-developed infant with dyspnea and circumoral cyanosis; the pulse rate was 140 beats per minute and the respiratory rate was 40 breaths per minute . The second heart sound was accentuated and single. A Grade 3/6 harsh ejection systolic murmur was heard at the upper left sterna l border radiating to the back . No diastolic murmur was heard. The liver was enlarged. Chest roentgenograms demonstrated a right aortic arch, moderate cardiac enlargement, and increased pulmonary vasculature. An electrocardiogram revealed evidence of left ventricular hypertrophy for a patient of this age (Fig. I). Cardiac catheterization data and cineangiography were consistent with the diagnosis of truncus arteriosus, type I, associated with pulmonary artery hypertension and a large ventricular septal defect. Because of worsening of the congestive heart failure, banding of the common pulmonary trunk
The Journal of Thoracic and Cardio vascular Surgery
was carried out on April 22, 1970. The pulmonary trunk arose from the truncus arteriosus immediately above the semilunar valve. The trunk was short, measuring less than 0.5 em. in length before giving rise to the right and left pulmonary artery branches. A heavy Tevdek suture was placed around the main pulmonary trunk and the vessel was constricted. The patient experienced multiple episodes of bradycardia requiring several injections of intracardiac calcium chloride as well as intravenous Isuprel. Eventually a stable state was achieved and the banding suture was secured. No measurements were made of the truncal or pulmonary artery pressures because of the precarious state of the patient. The postoperative course was extremely stormy; tracheostomy and a prolonged period of mechanical respiratory assistance was necessary. However, there were no further manifestations of congestive heart failure. The child was discharged to home care on July II, 1970, rece iving maintenance digoxin medication . The tracheostomy was permitted to remain in place because of tracheal narrowing. The patient grew and developed slowly but progressively until the age of 18 months, when increasing cyano sis and decreasing exercise tolerance became evident. He was observed thereafter for 10 months dur ing which time severe symptoms of hypoxia and a marked polycythemia developed. Physical examination at the age of 28 months revealed a child who was severely cyanotic at rest ; the body weight was 8.8 kilograms . Clubbing of the fingers and toes was present. No significant murmur was audible. The second heart sound was single and accentuated. The hemoglobin level was 24.7 Gm . per cent with a hematocrit value of 72 per cent. A chest roentgenogram revealed a concave pulmonary artery segment with sparse peripheral pulmonary vascular markings in both lung fields. An electrocardiogram indicated right axis deviation and right ventricular hypertrophy (Fig. 2). Cardiac catheterization was repeated on June 1, 1972, and confirmed the diagnosis of persistent truncus arteriosus with extreme constriction at the site of the pulmonary band. The mean pressure in the left pulmonary artery was 8 mrn. Hg as compared to 80/50 in the truncus arteriosus and 80/0 in the right ventricle. A left Blalock-Taussig anastomosis was created uneventfully when the boy was 29 months of age. Postoperatively, the physical examination revealed an improvement in color and a Grade 3/6 continuous murmur beneath the left clavicle. On the tenth postoperative day the tracheostomy tube was removed without complication. The patient was discharged to home care on Oct. I, 1972, in a much improved condition, and the subsequent course has been uneventful. The hemoglobin level on Feb. 7, 1973, was 19.1 Gm. per cent with a hematocrit value of 54.7 per cent.
Volume 66
Persistent truncus arteriosus 8 0 1
Number 5 November, 1973
Discussion
The herein described complication of banding of the pulmonary trunk in the palliative treatment of persistent truncus arteriosus may be anticipated to recur as more aggressive efforts in the surgical management of this lesion are pursued. Inadequate pulmonary blood flow of a severe degree was evident only 2 years after pulmonary artery banding, during which time the patient gained only 5 kilograms in body weight from 3.8 to 8.8 kilograms. In planning further surgical treatment, we decided that the small size of the patient precluded total correction by the method of McGoon and associates. " Such anatomic restoration should be undertaken only in patients of sufficient size to permit insertion of an aortic homograft adequate to serve in adult life, Direct relief of the constricting pulmonary artery band was also considered to be unwise since the use of cardiopulmonary bypass would be required and appropriate pulmonary flow could not be assured for the remote future. Therefore, a decision was made to create a systemic artery-pulmonary artery anastomosis. Billig and colleagues" had reported that this procedure provided successful palliation in a 6-day-old infant with truncus arteriosus (type II) who had diminished pulmonary blood flow secondary to congenitally hypoplastic pulmonary artery branches. In that very young patient, a side-to-side anastomosis of the right pulmonary artery to the truncus arteriosus resulted in a prompt increase of the arterial oxygen saturation. Thus the systemic artery-pulmonary artery anastomosis will yield the same hemodynamic benefits in a patient with a truncus arteriosus and inadequate pulmonary blood flow as in patients with a tetralogy of Fallot. For our patient, who had a right aortic arch and a body weight of 8.8 kilograms, a left Blalock-Taussig anastomosis was selected. The morbidity and mortality rates of banding of the pulmonary artery are greatest in the first few months of life, especially in patients with complex cardiac malformations. In the series of Takahashi and co-
aVL
V4R
Vi
V2
aVF
V3
Fig. 2. Twelve-lead electrocardiogram recorded prior to Blalock-Taussig anastomosis, when the child was 29 months old. Right ventricular hypertrophy is now apparent.
workers, " only 30 per cent of infants below the age of 3 months survived pulmonary artery banding, if the basic cardiac lesion was more complicated than an isolated ventricular septal defect. In addition, several specific difficulties must be anticipated in banding the pulmonary trunk or individual pulmonary arteries in infants with persistent truncus arteriosus. A narrow margin of safety in adjusting the tightness of the band will be present, especially if the vessels are of small size at the outset. There are mechanical difficulties inherent in performing the banding procedure in the posteriorly positioned pulmonary artery trunk or pulmonary artery branches as well as in judging the adequacy of the degree of banding in this position. Further, in the patient with an isolated ventricular septal defect, the force of pulmonary blood flow is directed into a large pulmonary artery by a right ventricle functioning at systemic pressure levels. The band under these circumstances must be sufficiently tight to oppose the thrust of both forward pressure and lateral pressure generated by the right ventricle in the pulmonary artery. In contrast, in the patient with truncus arteriosus, the pulmonary trunk or pulmonary arteries emerge from the truncus arteriosus at almost a right angle,
The Journal of
802
Friedman and Braitman
Thorocic and Cardiovasculor Surgery
thereby recervmg primarily only the thrust of lateral pressure from within the truncus. This factor may enhance the earlier and more rapid development of inadequate pulmonary blood flow in patients with this lesion. The reversal of the electrocardiographic pattern from left to right ventricular hypertrophy following banding of the pulmonary trunk was striking and the hemodynamic implications of this change are worthy of comment. In the presence of a large ventricular septal defect which is providing both ventricles with equal and unobstructed access to a large common arterial trunk, both ventricles oppose the same peripheral vascular resistance both before and after banding of the pulmonary trunk. Individual ventricular work loads before and after surgery were regulated, therefore, by the volume of the venous return to each ventricle. Prior to banding, the volume of pulmonary blood flow was high and the augmented pulmonary venous return accounted for left ventricular hypertrophy. After banding, the systemic venous return to the right side of the heart exceeded the pulmonary venous return and resulted in the picture of a dominant right ventricle in the electrocardiogram. The observation of these electrocardiographic changes suggests another useful method of estimation of the volume of pulmonary blood flow in patients with truncus arteriosus following banding of the pulmonary trunk.
Summary The problems in surgical management are described in an infant with persistent
truncus arteriosus who was subjected to banding of the pulmonary trunk at the age of 3 weeks because of intractable congestive heart failure. Within a 2 year period, the patient developed evidence of markedly reduced pulmonary blood flow which was successfully managed by the creation of a Blalock-Taussig anastomosis. Some of the special problems related to the banding of the pulmonary trunk or pulmonary arteries in patients with persistent truncus arteriosus are discussed. REFERENCES
2
3 4
5
6
7
Nadas, A S., and Fyler, D. C.: Pediatric Cardiology, ed. 3, Philadelphia, 1972, W. B. Saunders Company. Van Praagh, R., and Van Praagh, S.: The Anatomy of Common Aortopulmonary Trunk (Truncus Arteriosus Communis) and Its Embryologic Implications, Am. J. Cardiol. 16: 405, 1965. McGoon, D. C., Rastelli, G. C., and Ongley, P. A.: An Operation for the Correction of Truncus Arteriosus, J. A M. A. 205: 69, 1968. Wallace, R. B., Rastelli, G. C; Ongley, P. A., Titus, J. L., and McGoon, D. C.: Complete Repair of Truncus Arteriosus Defects, J. THORAe. CARDIQVASC. SURG. 57: 95, 1969. Heilbrunn, A, Kittle, C., and Diehl, A: Pulmonary Arterial Banding in the Treatment of Truncus Arteriosus, Circulation 29: 102, 1964 (Suppl 4). Billig, D. M., Kreidberg, M. B., Chernoff, H. L., and Khan, M. A: Systemic to Pulmonary Anastomosis in Truncus Arteriosus With Reduced Pulmonary Blood Flow, Am. J. Cardiol. 30: 288, 1972. Takahashi, M., Lurie, R., Petry, E., and King, H.: Clinical and Hemodynamic Effects of Pulmonary Artery Banding, Am. J. Cardiol. 21: 174, 1968.
Rrsistent truncus arteriosus is an uncommon variety of cyanotic congenital cardiac disease which is recognized to have a poor prognosis. In untreated cases, survival is rare beyond the age of six months." 2 The usual cause of death is congestive heart failure; excessive pulmonary blood flow and pulmonary hypertension contribute. In 1968, McGoon, Rastelli, and Ongley" described a surgical procedure for physiologic and anatomic correction of persistent truncus arteriosus, applicable in patients with undamaged pulmonary vasculature who are beyond infancy. The procedure involves the construction of a new pulmonary outflow tract by insertion of an aortic homograft and valve into the superior portion of the right ventricle, closure of the ventricular septal defect in a manner to produce continuity between the left ventricle and truncus arteriosus, and connection of the pulmonary artery branches to the new main pulmonary artery represented by the aortic homograft.
From the Division of Cardiology, The Children's Hospital of Philadelphia, and the Department of Pediatrics, School of Medicine. University of Pennsylvania, Philadelphia, Pa. 19146. Received for publication June 7, 1973.
The youngest patient successfully treated by this method was 3 years of age'; older and larger subjects are obviously more favorable candidates. In 1964 banding of the pulmonary trunk or the individual pulmonary arteries was reported to control congestive heart failure in patients with persistent truncus arteriosus." Restriction of pulmonary blood flow may serve not only to provide palliation until a favorable age and size for surgical correction is reached, but also to protect the pulmonary vascular bed from pulmonary vascular occlusive changes in the interim. The purpose of this report is to describe an infant with persistent truncus arteriosus who was in intractable congestive heart failure. Palliation by pulmonary truncal banding at the age of 3 weeks was successful, but the child developed signs of grossly inadequate pulmonary blood flow only 2 years thereafter. Further surgical treatment was necessary in order to increase pulmonary blood flow and was successfully provided by the creation of a systemic artery-pulmonary artery anastomosis. This unusual sequence of events in the surgical treatment of persistent truncus arteriosus has not been previously described.
799
800
Friedman and Braitman
Fig. 1. Twelve-lead electrocardiogram recorded from a 3-week-old infant with persistent truncus arteriosus (type I) . The tracing. recorded prior to banding of the pulmonary trunk . shows left ventricular hypertrophy.
Case report K. K., a white boy, was born on March 31, 1970, following an uncomplicated term pregnancy. Apgar scores were 8 at 1 minute and 10 at 5 minutes. The first 3 days of life were uneventful. Rapid respirations (72 breaths per minute), dyspnea, and circumoral cyanosis were noted on the fourth day of life. Chest roentgenograms at this time showed card iac enlargement and accentuation of the pulmonary vasculature. Digitalization produced little improvement and the infant was transferred to The Children's Hospital of Philadelphia on April 10, 1970, for study and treatment of cyanotic congenital heart disease. Physical examination on admission revealed a well-developed infant with dyspnea and circumoral cyanosis; the pulse rate was 140 beats per minute and the respiratory rate was 40 breaths per minute . The second heart sound was accentuated and single. A Grade 3/6 harsh ejection systolic murmur was heard at the upper left sterna l border radiating to the back . No diastolic murmur was heard. The liver was enlarged. Chest roentgenograms demonstrated a right aortic arch, moderate cardiac enlargement, and increased pulmonary vasculature. An electrocardiogram revealed evidence of left ventricular hypertrophy for a patient of this age (Fig. I). Cardiac catheterization data and cineangiography were consistent with the diagnosis of truncus arteriosus, type I, associated with pulmonary artery hypertension and a large ventricular septal defect. Because of worsening of the congestive heart failure, banding of the common pulmonary trunk
The Journal of Thoracic and Cardio vascular Surgery
was carried out on April 22, 1970. The pulmonary trunk arose from the truncus arteriosus immediately above the semilunar valve. The trunk was short, measuring less than 0.5 em. in length before giving rise to the right and left pulmonary artery branches. A heavy Tevdek suture was placed around the main pulmonary trunk and the vessel was constricted. The patient experienced multiple episodes of bradycardia requiring several injections of intracardiac calcium chloride as well as intravenous Isuprel. Eventually a stable state was achieved and the banding suture was secured. No measurements were made of the truncal or pulmonary artery pressures because of the precarious state of the patient. The postoperative course was extremely stormy; tracheostomy and a prolonged period of mechanical respiratory assistance was necessary. However, there were no further manifestations of congestive heart failure. The child was discharged to home care on July II, 1970, rece iving maintenance digoxin medication . The tracheostomy was permitted to remain in place because of tracheal narrowing. The patient grew and developed slowly but progressively until the age of 18 months, when increasing cyano sis and decreasing exercise tolerance became evident. He was observed thereafter for 10 months dur ing which time severe symptoms of hypoxia and a marked polycythemia developed. Physical examination at the age of 28 months revealed a child who was severely cyanotic at rest ; the body weight was 8.8 kilograms . Clubbing of the fingers and toes was present. No significant murmur was audible. The second heart sound was single and accentuated. The hemoglobin level was 24.7 Gm . per cent with a hematocrit value of 72 per cent. A chest roentgenogram revealed a concave pulmonary artery segment with sparse peripheral pulmonary vascular markings in both lung fields. An electrocardiogram indicated right axis deviation and right ventricular hypertrophy (Fig. 2). Cardiac catheterization was repeated on June 1, 1972, and confirmed the diagnosis of persistent truncus arteriosus with extreme constriction at the site of the pulmonary band. The mean pressure in the left pulmonary artery was 8 mrn. Hg as compared to 80/50 in the truncus arteriosus and 80/0 in the right ventricle. A left Blalock-Taussig anastomosis was created uneventfully when the boy was 29 months of age. Postoperatively, the physical examination revealed an improvement in color and a Grade 3/6 continuous murmur beneath the left clavicle. On the tenth postoperative day the tracheostomy tube was removed without complication. The patient was discharged to home care on Oct. I, 1972, in a much improved condition, and the subsequent course has been uneventful. The hemoglobin level on Feb. 7, 1973, was 19.1 Gm. per cent with a hematocrit value of 54.7 per cent.
Volume 66
Persistent truncus arteriosus 8 0 1
Number 5 November, 1973
Discussion
The herein described complication of banding of the pulmonary trunk in the palliative treatment of persistent truncus arteriosus may be anticipated to recur as more aggressive efforts in the surgical management of this lesion are pursued. Inadequate pulmonary blood flow of a severe degree was evident only 2 years after pulmonary artery banding, during which time the patient gained only 5 kilograms in body weight from 3.8 to 8.8 kilograms. In planning further surgical treatment, we decided that the small size of the patient precluded total correction by the method of McGoon and associates. " Such anatomic restoration should be undertaken only in patients of sufficient size to permit insertion of an aortic homograft adequate to serve in adult life, Direct relief of the constricting pulmonary artery band was also considered to be unwise since the use of cardiopulmonary bypass would be required and appropriate pulmonary flow could not be assured for the remote future. Therefore, a decision was made to create a systemic artery-pulmonary artery anastomosis. Billig and colleagues" had reported that this procedure provided successful palliation in a 6-day-old infant with truncus arteriosus (type II) who had diminished pulmonary blood flow secondary to congenitally hypoplastic pulmonary artery branches. In that very young patient, a side-to-side anastomosis of the right pulmonary artery to the truncus arteriosus resulted in a prompt increase of the arterial oxygen saturation. Thus the systemic artery-pulmonary artery anastomosis will yield the same hemodynamic benefits in a patient with a truncus arteriosus and inadequate pulmonary blood flow as in patients with a tetralogy of Fallot. For our patient, who had a right aortic arch and a body weight of 8.8 kilograms, a left Blalock-Taussig anastomosis was selected. The morbidity and mortality rates of banding of the pulmonary artery are greatest in the first few months of life, especially in patients with complex cardiac malformations. In the series of Takahashi and co-
aVL
V4R
Vi
V2
aVF
V3
Fig. 2. Twelve-lead electrocardiogram recorded prior to Blalock-Taussig anastomosis, when the child was 29 months old. Right ventricular hypertrophy is now apparent.
workers, " only 30 per cent of infants below the age of 3 months survived pulmonary artery banding, if the basic cardiac lesion was more complicated than an isolated ventricular septal defect. In addition, several specific difficulties must be anticipated in banding the pulmonary trunk or individual pulmonary arteries in infants with persistent truncus arteriosus. A narrow margin of safety in adjusting the tightness of the band will be present, especially if the vessels are of small size at the outset. There are mechanical difficulties inherent in performing the banding procedure in the posteriorly positioned pulmonary artery trunk or pulmonary artery branches as well as in judging the adequacy of the degree of banding in this position. Further, in the patient with an isolated ventricular septal defect, the force of pulmonary blood flow is directed into a large pulmonary artery by a right ventricle functioning at systemic pressure levels. The band under these circumstances must be sufficiently tight to oppose the thrust of both forward pressure and lateral pressure generated by the right ventricle in the pulmonary artery. In contrast, in the patient with truncus arteriosus, the pulmonary trunk or pulmonary arteries emerge from the truncus arteriosus at almost a right angle,
The Journal of
802
Friedman and Braitman
Thorocic and Cardiovasculor Surgery
thereby recervmg primarily only the thrust of lateral pressure from within the truncus. This factor may enhance the earlier and more rapid development of inadequate pulmonary blood flow in patients with this lesion. The reversal of the electrocardiographic pattern from left to right ventricular hypertrophy following banding of the pulmonary trunk was striking and the hemodynamic implications of this change are worthy of comment. In the presence of a large ventricular septal defect which is providing both ventricles with equal and unobstructed access to a large common arterial trunk, both ventricles oppose the same peripheral vascular resistance both before and after banding of the pulmonary trunk. Individual ventricular work loads before and after surgery were regulated, therefore, by the volume of the venous return to each ventricle. Prior to banding, the volume of pulmonary blood flow was high and the augmented pulmonary venous return accounted for left ventricular hypertrophy. After banding, the systemic venous return to the right side of the heart exceeded the pulmonary venous return and resulted in the picture of a dominant right ventricle in the electrocardiogram. The observation of these electrocardiographic changes suggests another useful method of estimation of the volume of pulmonary blood flow in patients with truncus arteriosus following banding of the pulmonary trunk.
Summary The problems in surgical management are described in an infant with persistent
truncus arteriosus who was subjected to banding of the pulmonary trunk at the age of 3 weeks because of intractable congestive heart failure. Within a 2 year period, the patient developed evidence of markedly reduced pulmonary blood flow which was successfully managed by the creation of a Blalock-Taussig anastomosis. Some of the special problems related to the banding of the pulmonary trunk or pulmonary arteries in patients with persistent truncus arteriosus are discussed. REFERENCES
2
3 4
5
6
7
Nadas, A S., and Fyler, D. C.: Pediatric Cardiology, ed. 3, Philadelphia, 1972, W. B. Saunders Company. Van Praagh, R., and Van Praagh, S.: The Anatomy of Common Aortopulmonary Trunk (Truncus Arteriosus Communis) and Its Embryologic Implications, Am. J. Cardiol. 16: 405, 1965. McGoon, D. C., Rastelli, G. C., and Ongley, P. A.: An Operation for the Correction of Truncus Arteriosus, J. A M. A. 205: 69, 1968. Wallace, R. B., Rastelli, G. C; Ongley, P. A., Titus, J. L., and McGoon, D. C.: Complete Repair of Truncus Arteriosus Defects, J. THORAe. CARDIQVASC. SURG. 57: 95, 1969. Heilbrunn, A, Kittle, C., and Diehl, A: Pulmonary Arterial Banding in the Treatment of Truncus Arteriosus, Circulation 29: 102, 1964 (Suppl 4). Billig, D. M., Kreidberg, M. B., Chernoff, H. L., and Khan, M. A: Systemic to Pulmonary Anastomosis in Truncus Arteriosus With Reduced Pulmonary Blood Flow, Am. J. Cardiol. 30: 288, 1972. Takahashi, M., Lurie, R., Petry, E., and King, H.: Clinical and Hemodynamic Effects of Pulmonary Artery Banding, Am. J. Cardiol. 21: 174, 1968.