Pulmonary artery banding

November 1984

Volume 88, Number 5, Part 1

THORACIC AND CARDIOVASCULAR SURGERY The Journal of

J

THORAC CARDIOVASC SURG

88:645-653, 1984

Original Communications

Pulmonary artery banding Two hwtdred nine children with congenital heart defects characterized by excessive pulmonary blood flow underwent pulmonary artery banding at The Hospital for Sick Cbildren from January, 1972, through December, 1982. The indicatiOiti for banding, rather than complete repair, varied with the type of cardiac defect as weDas with the year of presentation to our hospitaL A simptified method of estimating required band circumference bas been developed for infants with ventricular septal defect, with or without major intracardiac mixing disorders. Infants with simple defects without intracardiac bidirectional mixing disorders receive a band at a circumference of 20 mm + 1 mm for each kilogram of body weight, whereas infants with bidirectional mixing disorders receive a band at a circumference of 24 mm + 1 mm for each kilogram of body weight. The overaU operative mortality varies with the wtderlying cardiac defect and with associated medical conditiOlti but is relatively low in the less-complicated cases. The use of a formula to predict a starting band circumference, with loosening only as required by cyanosis or bradycardia, aUows predictable control of congestive symptoms and pulmonary hypertension in the majority of infants. The cumbersome measurement of pulmonary artery pressure and the unpredictable changes in pressure during anesthesia are avoided. Pulmonary artery banding remains an effective means of achieving satisfactory paUiatioo in infants with congenital heart disease and excessive pulmonary blood flow.

Robert A. Albus, Lieutenant Colonel, MC, USA * (by invitation), George A. Trusler, M.D., Teruo Izukawa, M.D. (by invitation), and William G. Williams, M.D. (by invitation),

Toronto, Ontario, Canada

A

From the Divisions of Cardiovascular Surgery and Cardiology. 'University of Toronto, and The Hospital for Sick Children, Toronto, Ontario, Canada. Read at the Sixty-fourth Annual Meeting of The American Association for Thoracic Surgery, New York, N. Y., May 7-9, 1984. Address for reprints: G. A. Trusler, M.D., Head, Division of Cardiovascular Surgery, The Hospital for Sick Children, Room 1525. 555 University Ave., Toronto, Ontario. Canada M5G IX8. •Assistant Professor, Uniformed Services University of the Health Sciences, Bethesda, Md.

variety of congenital heart lesions with increased pulmonary blood flow can be effectively palliated by pulmonary artery banding. I, 2 Since the introduction of pulmonary artery banding in 1951,3 many different band materials and banding techniques have been proposed and successfully applied.v' In 1972 we 6 reported a method that attempted to predict the band circumference from the weight of the infant. The present study reviews our subsequent experience in order to demonstrate the current status of pulmonary artery banding.

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Albus et al.

Table I. Summary of results

Diagnosis Group I VSD* VSD/ASD* DORV /subaortic VSDt AVCt VSD/coarctation* Subtotal

No. of patients 27

5 8 26 44

Percent banded according to formula (± 1.5 mm)

63 40 38 33 84

110

Group /I TGA/VSD TGA/VSD/coarctation DORV/subpulmonic VSDt Single ventriclet Subtotal

15 6 12 26 59

100 100 100

Group /II Mitral atresiat Mitral stenosis Hypoplastic Lvt Miscellaneous Subtotal

10 4 4 5 23

80 50

92

97

Improvement

G

I

M

19 5 8 12 15 59

6 0 0 10 14 30

10 0 8 18 36

I

Deaths

s

No.

I

%

I

I

4

0 0 2 8 II

0 0 2 7 10

8 16 9

2 2 2 2 8

2 2 0 3 7

2 2 3 8

3

I

I

0

0

I

4

2

3 0 0 3 6

I

6.6 33 17

12 13.5

3 3 3 2

40

II

48

30 75 75

Normal PAP at late cath. (%)

96 100 83 80 88 88 78 67 100 71 79 75 100 80

Legend: G, Good. M, Moderate. S, Slight. PAP, Pulmonary artery pressure. VSD, Ventricular septal defect. ASD, Atrial septal defect. DORV, Double-outlet right ventricle. AVC, Complete atrioventricular septal defect. TGA, Transposition of the great arteries. LV, Left ventricle.I-TGA, Leva-transposition of the great arteries. The Group I formula is 20 mm + 1 mm for each kilogram regardless of the presence of an ASD. The Group II and III formula is 24 mm + I mm for each kilogram regardless of the presence of an ASD. Percent by formula is considered ± I mm circumference. *Includes patients with I-TGA, VSD, or I-TGAjVSDjASD. t lncludes patients with simultaneous coarctation repair (see results for breakdown). :j:lncludes d- and l-transposition and tricuspid atresia.

Patients and methods From January, 1972, through December, 1982,209 patients underwent pulmonary artery banding at The Hospital for Sick Children, Toronto, Ontario. The chief indications for banding were to control congestive heart failure and to prevent pulmonary vascular disease. In most patients, an anterior thoracotomy gave adequate exposure for banding with or without atrial septectomy, but a posterolateral thoracotomy was used for simultaneous coarctation repair or ductus ligation. The banding material was a 4 mm wide strip of Teflon with a radiopaque marker and was coated with silicone rubber.* In the absence of proved or suspected significant pulmonary vascular disease, the intended band circumference was marked in advance according to the infant's body weight and cardiac defect. Previous experience had shown that infants less than 1 year of age with left-to-right shunts and no complicating intracardiac mixing disorders could usually have a relatively tight band, at a band circumference of 20 mm + 1 mm for each kilogram of the infant's weight. If there was an *See letter to the Editor, this issue (page 792).

atrial septal defect (ASD) or if the pulmonary artery was large, 1 or 2 mm was added to the band circumference. Infants with bidirectional intracardiac mixing disorders were given looser bands, at a circumference of 24 mm + 1 mm for each kilogram of the infant's weight. Prior to final band application, the lungs were well inflated and the airway was cleared of secretions. The band was loosened in the event of distal pulmonary artery collapse, cyanosis, or bradycardia, and the band was tacked with sutures to the pulmonary artery wall just above the pulmonary valve. In infants who were eventually to undergo arterial repairs for transpositionof the great arteries (TGA), the band was placed slightly more distally to be certain of protecting the pulmonary valve. One hundred ninety-two of the 209 patients were treated by this method. The other 17 patients were thought to have significant pulmonary vascular disease, and the band was placed so that distal pulmonary artery pressure was reduced to 50% of systemic arterial pressure. These 17 are excluded from further analysis. Three major categories and multiple subcategories were considered in this analysis. Group I-patients without

Volume 88 Number 5. Part 1 November, 1984

significant bidirectional mixing disorders-included infants with ventricular septal defect (VSD), levotransposition of the great arteries with VSD (1-TGA/ VSD), double-outlet right ventricle (DORV) with subaortic VSD, and the complete form of atrioventricular septal defect without significant atrioventricular valve regurgitation (AVC). Group II-patients with significant bidirectional mixing disorders-included infants with complete TGA with VSD, DORV with a subpulmonary VSD, single ventricle, and tricuspid atresia or stenosis. Group III included infants with a variety of defects: mitral atresia, interrupted aortic arch with VSD, total anomalous pulmonary venous drainage with VSD, or a combination of major defects such as TGA with AVC. The records of all children banded at The Hospital for Sick Children, Toronto, between January, 1972, and December, 1982, were reviewed. Their ages, weights, diagnoses, catheterization reports, operative notes, postoperative courses, and long-term results were recorded and categorized. The immediate success of the banding procedure was judged in a subjective fashion. Only those infants with short (less than 3 days) stays in the intensive care unit, who were ready for discharge from the cardiac ward by 14 days postoperatively, were considered to have had good results. If the infant needed band readjustments, prolonged ventilation, or subsequent complete repair and had only slight control of congestive cardiac failure, the banding operation was considered a failure. Infants who required prolonged hospitalization on the cardiac ward (14 to 45 days), primarily for difficulty with feeding and weight gain, but who were eventually discharged with effective palliation of their disease were considered to have a moderately successful result. Patients with simultaneous coarctation repair were analyzed separately within each group. Late catheterization data were reviewed, and pulmonary artery pressure was considered normal if less than 30 mm Hg systolic. If the pulmonary artery could not be entered at catheterization, then the pressure was assessed by the surgeon at complete repair. Patients who underwent banding at other institutions and complete repair at The Hospital for Sick Children were combined with patients who underwent banding at our institution only when results of complete repair were being analyzed. Results (Table I) The incidence of morbidity of the banding procedure itself is low. Six patients had phrenic nerve palsy and one had vocal cord paresis. Four infants had infected bands, and pulmonary artery aneurysms developed. Only nine

Pulmonary artery banding

647

patients required band tightening. In eight patients the bands migrated distally and significantly impaired right pulmonary artery flow. Mild right pulmonary artery stenosis was common. Adhesions found at the time of complete repair were variable and certainly contributed to the difficulty of complete repair in some cases. Group I: VSD without significant mixing disorder. VSD and VSD/l- TGA without coarctation of aorta. Thirty-two infants with a large VSD underwent pulmonary artery banding in the first year of life. Two of these infants had I-TGA and five had an ASD. Twelve VSDs were perimembranous, 17 muscular or multiple, two infundibular, and one inlet posterior type. There was one early death (3%). This infant had undergone repair of a diaphragmatic hernia 2 weeks earlier and weighed 2.1 kg when she underwent banding. The band was applied 2 mm looser than formula because of a large pulmonary artery. She tolerated endotracheal extubation but continued to have congestive cardiac failure and died I month postoperatively. One additional infant died I month after banding. She was born prematurely, weighed 1.8 kg, and died of sepsis and multiple systems failure complicating DiGeorge syndrome. In 17 of 27 infants with VSD and without ASD, the band was sized to predicted circumference. Thirteen had a good response, three moderate, and one slight. Ten required a slightly looser band; six had good responses, three moderate, and one infant died. In two of the five infants with VSD and ASD the band was applied according to the VSD formula, and in three it was applied loosely.All five had good early results. Twenty-three children underwent catheterization 3 weeks to 5 years postoperatively. In 22 (95%) the pulmonary artery pressure was normal. In one patient, who had only accepted a band 3 mm looser than predicted, there was a moderate elevation (46/27 mm Hg). Twenty-six children, including four who underwent banding elsewhere, underwent VSD closure and pulmonary artery band removal with no deaths. VSD with coarctation ofthe aorta. Forty-one infants with large VSDs and coarctation of the aorta underwent pulmonary artery banding and simultaneous coarctation repair. Another three infants had pulmonary artery banding within 3 weeks of coarctation repair. Four of these 44 patients had 1-TGA as well. Twenty-nine were less than I month of age and 3 less than 1 week at the time of operation. Thirty-nine VSDs were perimembranous, four multiple, and one muscular. Seven (16%) of the 44 infants died early after operation. One of these infants was moribund at banding and died 3 months later with myocardial calcification, a necrotic colon, and

6 4 8 Albus et af.

polycystic kidneys. A second early death occurred in a patient with tubular hypoplasia of the transverse aortic arch. The other five deaths included one infant in whom the band was applied loosely (3 rom beyond the rule) and who continued in congestive heart failure. He died at attempted VSD closure at 1 month of age. Of the 44 infants, 33 accepted bands within 1.5 rom of our formula. Four died, 23 had good or moderate improvement, and six had only slight improvement. Eleven infants required bands looser than predicted. Three died, six had good or moderate responses, and two had slight improvement. Two of the eight patients with only a slight improvement with banding underwent successful early VSD closure at 4 and 7 months of age. Twenty-eight children underwent catheterization 18 months to 8 years postoperatively. In 24 (86%) the pulmonary artery pressure was normal. In two there was a moderate elevation (53/22 and 57/28 rom Hg), and in two the bands had moved distally; the left pulmonary artery pressure were 40/11 and 36/0 rom Hg and the right pulmonary arteries were narrowed severely. The VSD had spontaneously closed in four patients (14%). Twenty-eight patients, including one who had banding at another hospital, have undergone elective pulmonary artery reconstruction and VSD closure, with two operative deaths (7%). DORV with subaortic VSD. Eight infants with DORV and a subaortic VSD underwent pulmonary artery banding in the first year of life. None of the infants had significant cyanosis or mixing disorders detected at catheterization. Only two were less than 3 months of age. Two had significant coarctation of the aorta. All survived with good operative results. Only three of the eight infants, however, accepted a band at the pre-marked circumference. Significant cyanosis developed in the other five and necessitated a larger band. Five of the eight children accepted the band at a circumference of 22 rom + I rom for each kilogram of body weight. One infant had a simultaneous BlalockHanlon septectomy. Six children had late cardiac catheterization, and only one had mild elevation of pulmonary artery pressure (38/12 rom Hg). Six children, including one who underwent banding at another hospital, had complete repair; there were two operative deaths. AVe. Twenty-six infants with Ave underwent pulmonary artery banding in the first year of life. Thirteen infants (50%) had chromosomal trisomy 21. The disposition of the atrioventricular valve was considered balanced in 14, left ventricular dominant in seven, and right ventricular dominant in five. Mitral regurgitation was described as moderate in five, mild in nine, and absent in

The Journal of Thoracic and Cardiovascular Surgery

12. No infants had multiple VSDs at angiography, and only one had a coexistent coarctation of the aorta. There were two early deaths (7.7%). Only nine infants accepted a band at the predicted circumference. Improvement was good in three and moderate in four, and there were two deaths. In 17 infants the band was applied more loosely than predicted, with good improvement in eight, moderate in seven, and slight in two. Pulmonary artery pressure was normal in eight of 1() children (80%) 1 to 6 years postoperatively. Three children died prior to further operation. One died of congestive cardiac failure at 3 months, one of severe pulmonary emphysema at 2 years, and one of an internal bowel hernia at 1 year. Fifteen children, including seven whose banding was performed at other hospitals, have undergone AVe repair and pulmonary artery banding, with four operative deaths (27%). Group II: VSD with significant mixing disorder. Complete TGA with VSD. Twenty-one infants with TGA and VSD, less than 6 months of age, underwent pulmonary artery banding. Eleven infants were less than 1 month of age. Six of the 21 infants had concurrent coarctation repair, and 15 had concurrent BlalockHanlon septectomy or an Edwards procedure. Of the six infants who had concurrent coarctation repair, two died (33%), two had slight improvement, and two had moderate improvement. All bands were applied strictly according to the formula (24 rom + 1 rom for each kilogram of body weight). Three of the four survivors had postoperative catheterization, and one of these had an elevated left pulmonary artery pressure (55/16 rom Hg) due to distal slippage of the band. He died after an attempted Mustard procedure, VSD closure, and resection of left ventricular outflow tract obstruction. Another long-term survivor has undergone a successful arterial repair of TGA with VSD closure. Among the 15 patients without coarctation repair, there were 10 with good improvement (67%), two with moderate improvement (13%), two with only slight improvement (13%), and one death (6.6%). All bands were applied strictly according to our formula (24 rom + 1 rom for each kilogram of body weight). All 14 operative survivors had postoperative catheterization. Pulmonary artery pressure was normal in 11 (78%), moderately elevated in two (one of whose band had slipped), and severely elevated in one child, also with a band that had slipped distally. Thirteen have had complete repair, nine by the Mustard technique with three surgical deaths and four by an arterial repair with two surgical deaths. Two of the three patients with

Volume 88

Pulmonary artery banding 6 4 9

Number 5, Part 1 November, 1984

Table II Diagnosis Mitral atresia Mitral atresia, coarctation of aorta Mitral stenosis Hypoplastic left ventricle YSD, coarctation, total anomalous pulmonary venous drainage Aye, TGA, partial anomalous pulmonary venous drainage Single ventricle with subaortic stenosis AYe, double-inlet and double-outlet right ventricle Aortopulmonary window Total

No.

7 3 4 4

Early deaths I 2 3 3

1 1 1 1

1 0 1 0 0

23

II

I

Late deaths 2

o o

o 1

o 4

For legend see Table I.

elevated pulmonary artery pressures were among the surgical deaths. DORVand subpulmonic VSD. Twelve infants with DORV and subpulmonic VSD (Taussig-Bing deformity), less than 6 months of age, underwent pulmonary artery banding. Four had concurrent coarctation repair, and six had concurrent Blalock-Hanlon or Edwards procedures. All bands were applied according to formula (24 rom + 1 rom for each kilogram of body weight) or slightly tighter. Eight had good improvement, two moderate, and two died of infection at the pulmonary artery banding site. Seven children have had late catheterization with normal pulmonary artery pressures in all. Six have undergone repair, with three operative deaths. Single ventricle or tricuspid atresia. Twenty-six infants less than 6 months of age (including five less than 10 days of age), with a diagnosis of single ventricle or tricuspid atresia, underwent pulmonary artery banding. Twelve infants had TGA and nine had 1-TGA. Nine had coarctation of the aorta repaired. In 24 of the 26 infants, the band was applied according to the rule for VSD with a mixing disorder (24 rom + 1 rom for each kilogram of body weight). Two infants requireda band tighter than the predicted circumference. Eighteen infants had good improvement (69%), two moderate (8%), three slight (11.5%), and three died (11.5%). Subaortic stenosis developed during follow-up in eight infants. One died at VSD enlargement and another at attempted creation of a left ventricular apico-aortic conduit. Two were managed successfully by creation of an aortopulmonary window proximal to the banding site, and three had an aortopulmonary anastomosis at the time of definitive atriopulmonary anastomosis. Of the 14 children undergoing late catheterization, 10 had normal pulmonary artery pressures (71%) and four had high pulmonary artery pressures (62/6, 50/22,

50/11, and 45/15 rom Hg). Four children with single ventricle have undergone atriopulmonary anastomosis, with one survivor who remains in poor condition 4 years postoperatively. Of the 16 children with single ventricle who underwent pulmonary artery banding more than 5 years ago, only seven remain alive. Group III: Miscellaneous. Twenty-three infants less than 1 year of age, with a variety of complex cardiac defects, underwent pulmonary artery banding (Table 11). . Discussion In 1972 we6 reported a method of choosing a band circumference in infants with large VSDs with and without TGA. The method is based on two principles: (1) blood flow across a constriction is determined by (a) the pressure gradient across the constriction, (b) the length of the narrowed segment, and (c) its luminal diameter; (2) the blood flow required by an infant will vary according to his size or weight. 7 Based on our experience using a 4 rom wide band of Teflon tape, we were able to derive a simple formula for estimating the required band circumference in infants with and without TGA. Infants with simple VSD usually can accept a relatively tight band at a circumference of 20 rom + 1 rom for each kilogram of the infant's weight. This appears to reduce pulmonary blood flow to a level close to normal for the infant. Infants with TGA, however, become severely cyanosed if the band is this tight; instead, the band circumference should be 24 rom + 1 rom for each kilogram of the infant's weight. Pulmonary blood flow then seems to be close to twice the normal flow. A single millimeter of variation in band circumference can often result in a significant difference in blood flow, cyanosis, or cardiac failure. The same principle is used in infants with more complex cardiac anatomy. If there is bidirectional intracardiac mixing with cyanosis,

6 50

The Journal of Thoracic and Cardiovascular Surgery

Albus et al.

35

VSD GOOD RESPONSE. VSD FAIR. SLIGHT RESPONSE. VSD. ASD GOOD RESPONSEo DEATH •

30

-

w

U

Z

w IE: w

o

- - BEST FIT LINEAR REGRESSION OF GOOD RESULTS VSD ONLY ly=19.62 +1.5xl FORMULA (y=20+x)

•

o

. . -_.-- --. •

o -..,." )j.. _ _. . . . . .

25

•

_ v= 19.62+1.5x

y=20+x

•

~

~ :::l U

IE:

U

o z

«

m

15 L--_ _......l........ _ _--L 1

......

2

3

.....

......_ _........

4

5

6

WEIGHT IN KILOGRAMS

Fig. 1. Relation of band circumference to body weight in infants with ventricular septal defect (VSD). ASD, Atrial septal defect.

then a loose band (as in TGA with VSD) is utilized. If there is no intracardiac mixing or cyanosis, a tight band should be accepted. An ASD may allow right-to-left shunting so that a tight band may not be tolerated. Loosening the band slightly (I mm increased circumference) is usually sufficient to avoid this problem. A large pulmonary artery may also limit the tightness of the band circumference because infolding of the wall reduces the lumen. Overriding of the aorta, as found in DORV with subaortic VSD, may also cause early right-to-left shunting with a tight band. Pulmonary parenchymal disease, such as pneumonia or atelectasis, may increase cyanosis and prevent adequate tightness of the band and thus result in a poor response. Changing the width of the banding tape will alter the flow through the band. These results relate to a band of 4 mm width. The band is coated with silicone rubber which, while increasing the ease of band removal, does make it more prone to slip down to the pulmonary artery branches. The band should be stitched to the pulmonary artery adventitia to avoid slipping. Group I: VSD without significant mixing disorder. This group was composed of infants less than I year of age with VSD, AVC, VSD with I-TGA, and DORV with a subaortic VSD. In Group I, pulmonary artery banding is used chiefly for very small or very ill infants, infants with multiple or muscular VSDs, or with AVC and unbalanced atrioventricular valve disposition where a high risk of repair is anticipated. Therefore, this series of infants with Group

I lesions is highly selected and weighted toward complicated lesions. Excluding the infant with diaphragmatic hernia, the overall mortality for Group I was 8.2% and fell to 3.2% in the absence of coarctation of the aorta. Ninety-seven percent of all survivorswithout coarctation of the aorta were judged to show moderate or good improvement. Only 79% of surviving infants with coarctation were judged to show moderate or good improvement-perhaps a reflection of the coexistent coarctation rather than lack of control of pulmonary blood flow. In infants with VSD and coarctation, we first apply a pulmonary artery band at the predicted circumference and then repair the coarctation. Only six of 22 patients failed to tolerate the band at that circumference and required a looser band. Some infants may undergo coarctation repair and be observed for continued congestive cardiac failure or VSD closure without pulmonary artery banding. Estimation at catheterization of the size of the VSD or its potential for closure, however, has been difficult. The predicted band circumference for VSD seems to be as tight as most infants can tolerate. With any significant disturbance of myocardial or pulmonary function, a looser band may be required, and then the infant may derive less benefit. At the lower end of the weight scale, infants weighing 2 kg or less have shown a less predictable response to banding. It is our impression that the band should be about I mm tighter in at least some of these infants. The graph in Fig. I plots band circumference against

Volume 88 Number 5, Part 1 November, 1984

weight. The solid line represents the original formula for predicted band circumference for a VSD without a mixing disorder. The dashed line is derived from the data for infants in this series with a good banding result, fitted to a straight line using linear regression analysis by the least squares method (y = 19.6 + 1.5X). The two infants who had good results from banding, despite very loose bands when compared to the formula, had large pulmonary arteries and would not tolerate tighter bands. Other infants who varied widely from the predicted band circumference either had ASDs or were only moderately or slightly improved by operation. Perhaps the dashedline should have a steeper slope, for the lower or left-hand end of the line may be elevated abnormally by one patient with an inexplicably good result despite a loose band. The slight difference between the line representing our current good results (y = 19.6 + 1.5X) and the line generated by our previous report (y = 20 + x) tends to confirm our clinical impression that some very small infants (2 kg) require a band circumference 1 mm or 1.5 mm tighter than previously predicted, and infants of 5 to 6 kg weight may be well palliated with slightly looser bands. The formula could be used in only 38% of infants with DORV plus subaortic VSD. Attempts to apply tight bands in these infants resulted in bradycardia and hypotension. This is probably related to the early development of right-to-left shunting in the presence of overriding of the aorta. Despite the looser bands, the immediate control of congestive cardiac failure was good. We now recommend applying the band at a circumference of 22 mm + 1 mm for each kilogram of infant body weight. Banding in infants with AVC is controversial.v? Despite the complex and varied anatomy in these infants, the operative mortality rate was only 8%. However, in only 33% of our patients could the band be applied exactly according to the VSD formula. Perhaps this is a reflection of the presence of an atrial communication, a large pulmonary artery, and mitral regurgitation. Our experience suggests that, because of these factors, the band should be about 2 mm looser than for uncomplicated VSD. Thus, the formula becomes 22 nun + 1 mm for each kilogram of body weight. Ten of the II children with a good response (91%) and 21 of the entire group of 26 children (81%) accepted a band of this predicted circumference: ± 1.5 mm. The presence of trisomy 21, unbalanced atrioventricular valve orifice, or moderate mitral regurgitation did not influence the results of banding. Group II: VSD with significant mixing disorders. This group included infants with TGA, DORV with a

Pulmonary artery banding 6 5 1

subpulmonic VSD, single ventricle, and tricuspid atresia. This group is prone to early development of pulmonary vascular disease, and operative intervention is required in the first 6 months of life. All of these bands were adjusted strictly according to our predicted band circumference. Since the band is relatively loose to allow normal pulmonary blood flow and to avoid excessive hypoxia, the bands were all tolerated. There were 53 patients in this group with an overall operative mortality rate of 13.5%. Eighty-five percent of the survivors had good or moderate control of their congestive heart failure, and 79% had normal pulmonary artery pressures at late catheterization. The above normal pulmonary artery pressures were related to band slippage, which should be preventable. The patients with single ventricle or tricuspid atresia presented some late management difficulties. 10. 1\ Some developed a restrictive VSD (bulboventricular foramen) aggravated by, or uncovered by, the presence of the pulmonary artery band. This method for determining pulmonary artery band circumference is expecially useful in Group II patients. These infants have relatively complex intracardiac anatomy, and mixing disorders playa dominant role in their outcome. Calculation of acutal or effective pulmonary blood flow is difficult or impossible. This simple technique has been successful in allowing adequate but controlled pulmonary blood flow and pressure; when the technique is combined with atrial septostomy or septectomy, cyanosis has not been a problem. Group III: MisceUaneous. Group III consists of infants with mitral stenosis, mitral atresia, or miscellaneous complex cardiac disorders. These infants have complex cardiac anatomy and physiology and a high operative mortality both early and late. Only 12 of 23 patients survived banding, and only eight of the 12 are alive now awaiting further intervention. The technique is a simple way of achieving reasonable pulmonary artery banding for complex heart malformations. Recommendations No comparison between this series of patients and a similar group of infants without pulmonary artery banding is made. Some recommendations, however, can be based on our results. Infants with conditions for which a definitive repair is available in infancy with a reasonable operative risk should not undergo preliminary pulmonary artery banding. This includes infants with isolated membranous VSD, uncomplicated, balanced AVC, and some children with DORV and subaortic VSD. Infants with VSD and coarctation of the aorta may not require banding, but further analysis is

The Journal of Thoracic and Cardiovascular Surgery

6 5 2 Albus et al.

necessary before making a strong recommendation. The risk of a restrictive outflow tract developing in single ventricle with a subaortic chamber suggests that pulmonary artery banding should be avoided in this group. Infants for whom definitive repair is not available in infancy or in whom the risk of repair is high should undergo preliminary pulmonary artery banding. This includes infants with multiple or muscular VSDs, AVC with unbalanced atrioventricular connection, those with TGA with VSD who are less than 3 months of age, or infants with 1-TGAjVSD who are less than 1 year of age. Children with complex disease such as mitral atresia or tricuspid atresia with excessive pulmonary blood flow should also undergo pulmonary artery banding. Infants with mixing disorders (Group II) must be assured of adequate atrial communication before banding. Banding may also be indicated in some infants in any group with concomitant medical conditions such as sepsis or intracranial hemorrhage or major associated noncardiac anomalies.

2

3

4

5

6

7

8

9

10

REFERENCES Stewart S, Harris P, Manning J: Pulmonary artery banding. An analysis of current risks, results, and indications. J THORAC CARDIOVASC SURG 80:431-436, 1980 Dooley KJ, Lucy PB, Fyler DC, Nadas AS: Results of pulmonary arterial banding in infancy. Survey of 5 years' experience in the New England Regional Infant Cardiac Program. Am J Cardiol 36:484-488, 1975 Muller WH Jr, Dammann FJ Jr: The treatment of certain congenital malformations of the heart by the creation of pulmonic stenosis to reduce pulmonary hypertension and excessive pulmonary blood flow. A preliminary report. Surg Gynecol Obstet 95:213-219, 1952 Stark J, Berry CL, Silove ED: The evaluation of materials used for pulmonary artery banding. Experimental study in piglets. Ann Thorac Surg 13:163-169, 1972 Shane RA, Kimmell GO, Jaques WE, Campbell GS: Adjustable prosthesis for pulmonary artery banding. Comparison with umbilical tape and Teflon bands. Circulation 35:Suppl 1:148-151, 1967 Trusler GA, Mustard WT: A method of banding the pulmonary artery for large isolated ventricular septal defect with and without transposition of the great arteries. Ann Thorac Surg 13:351-355, 1972 Utley JR: Hemodynamic observations during and after pulmonary artery banding. Ann Thorac Surg 15:493-509, 1973 Epstein ML, Moller JH, Amplatz K, Nicoloff DM: Pulmonary artery banding in infants with complete atrioventricular canal. J THORAC CARDIOVASC SURG 78:28-31, 1979 Kirklin JW, Blackstone EH: Management of the infant with complete atrioventricular canal (editorial). J THORAC CARDIOVASC SURG 78:32-34, 1979 Penkoske PA, Freedom RM, Williams WG, Trusler GA,

Rowe RD: Surgical palliation of subaortic stenosis in the univentricular heart. J THORAC CARDIOVASC SURG 87:767781, 1984 11 Rao PS: Further observations on the spontaneous closure of physiologically advantageous ventricular septal defects in tricuspid atresia. Surgical implications. Ann Thoracic Surg 35:121-131, 1983

Discussion DR. JOHN W. BROWN Indianapolis. Ind.

At the Riley Children's Hospital in Indianapolis, we have performed pulmonary artery banding in a comparable number of infants less than 3 months of age with large shunts. Our technique is somewhat simpler than that employed by the Toronto group. The technique was developed by my senior associate, Dr. Harold King, and has been used for the past 12 years. The technique utilizes a Hegar dilator to adjust the band. We approach the pulmonary artery of the infant through a very limited left anterior thoracotomy. The incision is approximately 4 to 5 em in length and is halfway between the nipple and the supersternal notch lateral to the sternum. The pulmonary artery is encircled with a Dacron cord. The Hegar dilator is then laid alongside the main pulmonary artery, and the cord is tied over the Hegar dilator. The main pulmonary artery is instantaneously totally occluded, but then the Hegar dilator is withdrawn leaving the area inside the band equal to the area of the Hegar dilator. The degree of banding is not affected by wall thickness of the pulmonary artery or the surrounding adventitial tissue. For infants less than 3 months or 4 kg, we use a No. 6 Hegar dilator, which leaves a banded area for blood flow of 28 mm', For older or larger infants, we would use a No. 7 Hegar dilator, but no larger. We measure distal pulmonary artery pressures and arterial blood gases but do not alter the band tightness, since pressures and gases are misleading due to the varying degrees of congestive heart failure in these infants. The mortality in infants varies greatly with age. In our hands, mortality is high (45%) in infants less than I week of age but decrease to less than half that figure (19%) in patients that are between the sixth and twelfth weeks of life. Mortality for banding varies greatly with the anatomic lesion, as suggested by Dr. Albus. We have not had a death in the VSD group. However, the addition of coarctation, single ventricle, or other complex lesions increases the mortality significantly. I have three questions for the authors. First, what percentage of your group of infants is less than 3 months of age? Second, please describe a little more completely the type of banding material that you use. Third, do pressures alter your banding technique? DR. S. BERT LITWIN Milwaukee. Wis.

I would like to describe our results using an alternative surgical technique (Table I). The procedure is performed while monitoring aortic and distal pulmonary artery pressures.

Volume 88 Number 5, Part 1 November, 1984

Pulmonary artery banding

Table I. Pulmonary artery banding at Milwaukee Children's Hospital (1973-1983) Deaths

Group I VSD AVe DORV + subaortic VSD VSD + coarctation AVC + coarctation All Group I

Group II d-TGA + VSD or single ventricle DORV + subpulmonic VSD Single ventricle Tricuspid atresia Group III Mitral atresia or stenosis I-TGA + single ventricle Complex, miscellaneous

Patients

No.

23 11

-.1

37 17

1 2 ...Q 3 5

-.1

-.1

7

0

4 1 18

0 0 ...Q 0

3 6

2 0

20 57

....§.

8 40 19

0 0

~

-.1

5

38

88 68

16 8

18 11

13

Totals Excluding coarctation

8 11

~

Legend: YSD. Yentricular septal defect. Aye, Atrioventricularis communis. DORY, Double-outlet right ventricle. TGA, Transposition of the great arteries.

Ideally, pulmonary artery mean pressure is reduced to one third to one half of systemic pressure and there is usually a concomitant rise in systemic pressure. Peripheral arterial oxygen saturation is measured on an inspired oxygen fraction of 50%. No change should occur in infants with normally related great vessels, whereas fall in saturation of less than 5% to 10% is acceptable in the presence of TGA. Finally, right ventricular pressure is measured after completion of the banding procedure to rule out suprasystemic intraventricular pressure indicating left ventricular outflow tract obstruction. Our results in the past 11 years are similar in many ways to the Toronto experience. More of our Group I infants died, but there were no deaths in Group II babies. It is evident that the

653

combination of pulmonary artery banding and coarctation repair resulted in a considerable mortality. Three of the deaths in that group and eight deaths in the total group of 88 babies were due to subaortic stenosis or a restrictive VSD. Based on this, we no longer band the pulmonary artery at the time of coarctation repair when a discrete VSD is present. Banding would be performed only in the pressure of a complex VSD or single ventricle. Additionally, if left ventricular outflow tract obstruction is found, a looser band would be placed. Dr. Albus, using your technique, how do you define the presence of left ventricular outflow tract obstruction? If not by banding, how do you manage these patients? DR. ALBUS (Closing) I would like to thank the discussants for their comments. Dr. Brown had several questions, first regarding the percentage of infants less than 3 months of age. We did not specifically keep track of that in all the different subgroups. All of the patients in Group I were under 1 year of age, and all of those in Group II were under 6 months of age. The majority of the patients in both groups were under 3 months of age. The banding material used is a 4 mm wide strip of silicone rubber-eoated Teflon. The width of the material is very important, because changing the width does change the formula. We do believe that the resistance varies with the length of the obstruction in addition to the area of the obstruction. We have not measured pressures in the distal pulmonary artery in this particular series of infants. There were 17 other children who were over 1 year of age in whom we believe pulmonary vascular obstructive disease has at least begun to be a factor, and therefore in those children we do measure distal pulmonary artery pressure and try to adjust that pressure to approximately half of systemic pressure. Dr. Litwin, first a comment on the VSD in coarctation. A great deal of information in the literature on that subject is controversial, and we are part of that controversy. We do not know whether it is appropriate to place a band in these infants or not. These infants seem to present at a younger age. Twenty-nine of our 44 children were less than 1 month of age at the time of banding and presented a more complex anatomy than the simple VSD group. Left ventricular outflow tract obstruction is defined in our group of patients predominantly angiographically. We do not make any attempt to measure ventricular pressure at the time of placement of the band.