Surgical treatment of tetralogy of Fallot with pulmonary atresia

Surgical treatment of tetralogy of Fallot with pulmonary atresia Thirteen (16 percent) of 80 patients with tetralogy of Fallot and pulmonary atresia undergoing corrective operations between Jan. 1, 1967, and Jan. 1, 1978, died in the hospital. The hospital mortality rate was 13 percent (10 deaths) among the 77 patients with confluent right and left pulmonary arteries. The risk of operation was not significantly affected by age at operation or by use of a valved external conduit versus a transannular outflow patch. It was affected (p = 0.008) by the ratio of peak right ventricular to left ventricular pressure (PRVILV) immediately after repair. This (PRVILV) was determined primarily by size of left and right pulmonary arteries. An equation was developed relating postrepair PRVILV to diameter of right and left pulmonary artery (normalized by dividing by size of descending thoracic aorta), body surface area, and possible arborization abnormalities and stenoses of the right and left pulmonary arteries. Cardiac performance after repair was better in those in whom a transannular patch was used rather than a valved external conduit. Important pulmonary dysfunction postoperatively occurred more often in patients with large "bronchial" arteries than in those without them, but was less when these were not ligated. Four (8 percent) of 48 traced hospital survivors died late postoperatively. Reoperations late postoperatively were required only in patients receiving valved external conduits. Forty (91 percent) of 44 living traced patients are asymptomatic.

Ottavio Alfieri, M.D.* (by invitation), Eugene H. Blackstone, M.D. (by invitation), John W. Kirklin, M.D., Albert D. Pacifico, M . D . , and Lionel M. Bargeron, Jr., M.D. (by invitation), Birmingham, Ala.

O ince Lillehei and associates1 first reported the repair of tetralogy of Fallot and pulmonary atresia, many improvements have been made in preoperative evaluation, intraoperative management, and postoperative care. The wide spectrum of malformations included under this diagnosis has come to be appreciated, as have the considerable risks and imponderables associated with repair of some types of the malformation. Therefore, we have analyzed our experience with complete repair of tetralogy of Fallot and pulmonary atresia at the University of Alabama Medical Center to determine the influence of various factors on early and late results and to develop methods for improving the results. From the Departments of Surgery and Pediatrics, University of Alabama School of Medicine and Medical Center, Birmingham, Ala. Supported in part by Program Project Grant HL 11,310 from the National Heart, Lung and Blood Institutes, Bethesda, Md. Read at the Fifty-eighth Annual Meeting of The American Association for Thoracic Surgery, New Orleans, La., May 8, 9, and 10, 1978. Address for reprints: John W. Kirklin, M.D.. Department of Surgery, University Station, Birmingham, Ala. 35294. *At present, Assistant Surgeon in Cardiac Surgery, Hospital of Bergamo, Bergamo, Italy. 0022-5223/78/0376-0321$01.50/0 © 1978 The C. V. Mosby Co.

Material and methods Patients. Eighty patients with tetralogy of Fallot and pulmonary atresia underwent corrective operation between 1967 and 1978. The records for each patient were individually reviewed with consistent criteria to assure proper categorization and completeness and accuracy of the data. Sixty-two patients had congenital pulmonary atresia, which presumably had been present since birth. In 13 (21 percent) of these patients the main pulmonary artery trunk was completely absent, whereas in the rest of the patients at least a remnant of the main pulmonary artery was present. In three (5 percent) of the 62 patients, the right and left pulmonary arteries were nonconfluent. Eighteen (23 percent) of the 80 patients had acquired pulmonary atresia, either infundibular or valvular, which had developed after a previous aortopulmonary anastomotic procedure, and in all the main pulmonary artery was present. The size of the right and left pulmonary arteries was extremely variable, ranging from "very small" to "normal." A segmental stenosis of one of the two pulmonary arteries or stenosis at the confluence was not 321

The Journal of Thoracic and Cardiovascular Surgery

3 2 2 Alfieri et al.

Table HI. Repair of tetralogy of Fallot with pulmonary atresia (1967-1978)

Table I. Source of pulmonary blood flow in tetralogy of Fallot with pulmonary atresia (1967-1978) Source of pulmonary

Hospital deaths

No. of patients

blood flow

Patent ductus arteriosus Large " b r o n c h i a l " arteries Large paramediastinal collateral Coronary-pulmonary artery fistula Surgical shunt only None identified

15* 30t

Total

80

5* 3 26 1§

*Five patients also had surgical shunts, two others also had large "bronchial" arteries, and one had a large paramediastinal collateral. tNine patients also had surgical shunts. $One patient also had a surgical shunt. §Twelve-month-old infant, hematocrit value 80 percent.

Table II. Repair of tetralogy of Fallot with pulmonary atresia (1967-1978) Hospital deaths

%

No.

No.

<24 >24 < 48 >48 < 144 >144

2 6 37 35

0 3 7 3

0 50 19 9

0%-61%| 38%* 29% - 76% J (17% - 62%) 12% - 28% 1 14%*

Totals

80

13

16

12% - 22%

Age (mo.)

CL

4% - 17% J (10% - 19%)

Legend: CL = 7 0 percer t confide ice limi s. *p = 0.09.

uncommon. In two patients the left pulmonary artery was absent. The blood supply to the lungs in these patients was provided by a variety of sources (Table I). In the 26 patients with one or more previously surgically created systemic-pulmonary arterial shunts as the only source of pulmonary blood flow, the Blalock-Taussig anastomosis was the most common. About half of the patients presented with large systemic-pulmonary artery collaterals, originating either from the upper descending thoracic aorta ("bronchial" arteries) or from subclavian, innominate, or internal mammary arteries ("paramediastinal" collaterals). The latter, in contrast to the "bronchial" arteries, usually joined the pulmonary artery proximal to the hilum. Significant associated anomalies included mild to severe aortic incompetence (four patients), tricuspid incompetence (one patient), anomalous origin of the left anterior descending coronary artery (two patients), and multiple (two) ventricular septal defects (one patient).

Anatomic type Congenital with confluent

No.

%

59*

9

15

IO%-22% 54%-100%

No.

CL

RPA and LPA Congenital with nonconfluent RPA and LPA Acquired, infundibular Acquired, valvular

3

3

100

10 8

0 1

0 12

0%-17% 2%-36%

Totals

80

13

16

12%-22%

Legend: CL = 70 percent confidence limits. RPA, Right pulmonary artery, LPA, Left pulmonary artery. *In six patients the ventricular septal defect patch was perforated after total closure produced high ratio between peak right ventricular and left ventricular systolic pressure (one death).

The operation. Operation was done through a midline sternotomy with cardiopulmonary bypass in association with varying degrees of hypothermia to allow periods of low perfusion flow rates or total circulatory arrest. Early in this series, with the perfusate temperature at 28° to 32° C , the aorta was intermittently crossclamped for multiple periods of 15 to 20 minutes each. More recently, a single period of aortic cross-clamping was employed, and either cold or cold and cardioplegia were used for myocardial preservation during the ischemic period. The various surgically created aortopulmonary anastomoses were controlled in the usual ways. 2-4 When a patent ductus arteriosus or a coronarypulmonary artery fistula was the source of pulmonary blood supply, ligation or division was carried out after institution of cardiopulmonary bypass before cardiotomy. 5-7 Large "paramediastinal" collaterals were encircled with a ligature after dissection in the anterior mediastinum and were tied after extracorporeal circulation was instituted. A complementing lateral thoracotomy was performed in 11 patients to provide exposure for isolating and ligating large "bronchial" arteries in the early part of the series.8 Later in this experience, dissection and ligation of "bronchial" arteries were carried out through a midline sternotomy via the pleural space or the posterior pericardium (12 patients).9 (This was suggested by N. Shumway, personal communication.) Recently, we have elected not to dissect or ligate "bronchial" arteries (nine patients). The ventricular septal defect (VSD) was repaired by sewing into place with a continuous polypropylene suture a patch of knitted Dacron velour. By way of avoid-

Volume 76 Number 3 September, 1978

Tetralogy of Fallot with pulmonary atresia

323

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Q

<

0.7

S) O X

0.6

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0.1 0.0 AGE (YEARS) AT REPAIR

Fig. 1. Probability of hospital death according to age at time of repair (solid line). The dashed lines represent the 70 percent confidence limits. Logistic equation for the probability (Pr) of hospital death: Pr = 1/(1 + exp[I.O ± 0.58 + 0.006 ± 0.0045 • age]) where exp is the base of the natural logarithms. Significance level of coefficients: P(intercept) = 0.08, P(age) = 0.19. Correlation between coefficients: r = —0.84. ing damage to the bundle of His in repairing perimembranous VSD's, the base of the septal leaflet of the tricuspid valve was used for securing the patch at the posteroinferior portion of the defect. The VSD was somewhat anterior to the membranous septum in eight patients and had a muscular margin posteriorly; in these cases the patch was sutured circumferentially to the edge of the defect. An additional defect in the muscular septum was found in one patient and was closed with U-stitches reinforced by Teflon pledgets. Recently, when the ratio between the systolic pressure in the right ventricle and that in the left ventricle (PRV/LV) was about 1 or greater immediately after repair, cardiopulmonary bypass was re-established and a hole about 1 cm. in diameter was made in the VSD patch (six patients). Such cases are included in this series. A valved external conduit from the right ventricle to the distal pulmonary arterial tree was inserted in 48 patients, all of whom, except one, had congenital pulmonary atresia. The type of valved external conduit which was used varied. Fifteen patients, operated upon before February, 1973, received a composite Dacron homograft-valved conduit.10 Hancock heterograft-

valved woven Dacron conduits have been used in the rest of the patients who received a conduit.11 Five patients had a distal Y or T extension of their conduit and individual anastomoses to the right and left pulmonary arteries. Subsequent to September, 1972, we12 have paid particular attention to positioning the conduit well away from the sternum on the side opposite that of the ascending aorta, in the hopes of preventing its entrapment between the sternum and ventricles or aorta. Actually, we have included in this category one patient who had a stent-mounted heterograft placed orthotopically beneath a transannular patch. A woven Dacron transannular patch, beginning in the right ventricular infundibulum and extending to the bifurcation of the pulmonary artery, was used to correct the atresia in 25 patients, 15 of whom had congenital pulmonary atresia.13 Infundibulectomy without patch-graft enlargement, with or without pulmonary valvotomy, was done in seven patients, all with acquired pulmonary atresia. Relief of segmental stenoses of the pulmonary arteries was accomplished by a separate pericardial or woven Dacron patch or by proper tailoring of the distal portion of the conduit or transannular patch. One patient with severe aortic incompetence required

The Journal of Thoracic and Cardiovascular Surgery

3 2 4 Alfieri et al.

POST-REPAIR

P RV/LV

Fig. 2. Probability of hospital death according to ratio of right ventricular to left ventricular systolic pressure immediately after repair (solid line). The dashed lines represent the 70 percent confidence limits. Logistic equation: Pr = 1/(1 + exp[3.8 ± 0.89 - 2.7 ± 1.01 ■ PRV/LV]) (PRV/LV)

Significance level of coefficients: P(intercept) = 0.00002, P(PRV/LV) = 0.008. Correlation between coefficients: r = -0.93. Table IV. Repair of tetralogy of Fallot with pulmonary atresia (1967-1978) Type of repair Valved external conduit

Transannular patch

Deaths Anatomic types

No.

No.

Congenital with confluent RPA and LPA

59

14

Congenital with nonconfluent RPA and LPA Acquired, infundibular Acquired, valvular

3 10 8

3 1

Totals

80

8

No.

8 18* (CL12%-26%) 3 100 0 0

15

-

-

Deaths

Deaths

%

No.

Infundibulectomy

-

11 23t (CL16%-31%)

2 8

25

%

No.

No.

1 7* (CL1%-21%)

-

-

-

-

-

-

-

7

0 0 (CL0%-24%)

No.

0 1

-

0 12

2 8t ( C L 3 % 18%)

7

0

%

0

Legend: Deaths = Hospital deaths. CL = 70 percent confidence limits. RPA, Right pulmonary artery. LPA, Left pulmonary artery *p for difference = 0.26. tp for difference = 0.11.

aortic valve replacement with a Starr-Edwards composite-seat ball-valve prosthesis. In another patient with severe tricuspid valve incompetence, tricuspid annuloplasty was performed. Clinical measurements and categorization. Systolic pressures in the right and left ventricle were measured in the operating room in each patient, usually at

the completion of repair and again just before closing the chest. When both values were available, that obtained just before closing the chest was used in data analysis. Cardiac index was measured in the intensive care unit by the indicator-dilution technique with indocyanine green.14 Patients were considered to have important pulmo-

Volume 76 Number 3 September, 1978

Tetralogy of Fallot with pulmonary atresia

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Fig. 3. Probability of hospital death because of low cardiac output according to PRV/LV immediately after repair (solid line). The dashed lines represent the 70 percent confidence limits. Logistic equation: Pr = 1/(1 + exp[6.0 ± 1.43 - 4.3 ± 1.47 - PRV/LV]) Significance level of coefficients: P(intercept) = 0.00003, P(PRV/LV) = 0.003. Correlation between coefficients: r = -0.94. nary dysfunction after operation if they required intubation and ventilatory support for more than 3 days, required tracheostomy, required reintubation after elective extubation, or if they had hemorrhagic pulmonary edema with low left atrial pressure. In the analysis of the frequency of this complication, eight patients without evidence of important pulmonary dysfunction who died before the third postoperative day were not included, since they had no opportunity to meet these criteria. One patient who died in the operating room with hemorrhagic pulmonary edema and low left atrial pressure was included. Cause of hospital death was determined by careful review of the detailed clinical records and, when available (10 of the 13 deaths), autopsy data. Angiocardiographic review. Adequate angiocardiograms were available for retrospective review and study in 56 of the 80 patients. The age at operation, the anatomic type, and the source of pulmonary blood flow in these 56 patients were similar to those of the group of 80 patients.* Forty-six of them had congenital pulmonary atresia with confluent right and left pulmonary arteries. The diameter of the right and left pulmonary arteries before the origin of the first lobar branch and *Details of these data are available upon request.

Table V. Repair of tetralogy of Fallot with pulmonary atresia (1967-1978) Hospital deaths

Post repair

%

PRV/LV

No.

No.

<0.40 >0.40 < 0.65 >0.65 < 0.75 >0.75 < 1.00 >1.00

15 26 12 22* 5

1 4 1 3 4

7 15 8 14 80

Totals

80

13

16

12%1 | p = 0.0001

]

CL 1%-21% 8%-26% l%-26% 6%-26% 47%-97% 12%-22%

Legend: CL = 70 percent confidence limits. PRV/LV, Ratio of peak pressure in right ventricle over that in left. *Six patients had perforation of the ventricular septal defect patch after initial complete closure. In these six, PRV/LV > 1 before perforation and essentially 1 after perforation.

the diameter of the main pulmonary trunk before the bifurcation were measured in anteroposterior projection. Also measured was the diameter of the descending aorta at the level of the diaphragm. All measurements were made on one cineangiographic frame whenever possible. Otherwise, they were made on different frames made at the same point in the cardiac cycle. Presence or absence of segmental stenosis for each pulmonary artery was noted. Stenosis at the origin of the right or left pulmonary artery was considered to be

326

The Journal of Thoracic and Cardiovascular Surgery

Alfieri et al.

RIGHT PA AO

LEFT PA DIAMETER AO

Fig. 4. Scattergram of PRV/LV immediately after repair versus the sum of the ratio of the diameter of right pulmonary arteries over that of the descending aorta at the diaphragm (determined angiographically), plus a similar ratio using left pulmonary artery. Closed circles represent patients who received a valved external conduit; open squares represent patients who did not receive a conduit. The line of regression and the 95 percent confidence limits for the observations are shown. The equation is: PRV/LV = 1.42 ± 0.140 - 0.50 ± 0.095 ■ (RPA/AO + LPA/AO) Significance level of coefficients: P(intercept) < 0.0001, P(RPA/AO + LPA/AO) < 0.0001. Standard deviation of regression = 0.33. 2.0 1.8 1.6

3 a *>

1.2

UJ 1-

1 .U

n

1.1

< _i = > nn o _J

< o

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OBSERVED P

RV/LV

Fig. 5. Postrepair PRV/LV calculated from the multiple regression equation plotted against that observed immediately after repair. The line of identity is shown, r2 = 0.84.

present when the diameter at the origin was one half or less that of the artery before the first branch. In all cases meeting this criterion, stenosis was confirmed surgically. The arborization of the right and left pulmonary arteries was considered abnormal when one lobe or more of the lung on that side was not supplied by the branches of the pulmonary artery. Follow-up. In order to assess the long-term results of corrective surgery for this lesion, survivors who underwent repair before Jan. 1, 1977, were evaluated by direct examination, by detailed telephone conversations, or by questionnaires sent to them and to their physician. The date of inquiry for most patients was November, 1977. Statistical analysis. Data in proportional form are presented with 70 percent confidence limits. 13 Comparisons were made using the chi-square test or Fisher's exact test for a contingency table. Comparisons for continuous variables were made by use of the unpaired t test. The relationship of hospital mortality to continuous variables was analyzed by parametric analysis. 16 The relationship of PRV/LV to continuous and categorical variables was tested by multiple linear re-

Volume 76 Number 3 September, 1978

Tetralogy of Fallot with pulmonary atresia

1> 21

Table VI. Repair of tetralogy of Fallot with pulmonary atresia (1967-1978) Hospital deaths

No.

PRVILV (Mean ± S.D.)

No.

%

CL

Normal or moderately small* Very small or one absent*

52 28

0.55 ±0.187 1.06 ± 0.426t

5 8

10 29

5%-16% 19%-40%

Totals

80

13

16

12%-22%

Size of RPA and LPA

Legend: p = 0.03 for difference in hospital deaths. CL = 70 percent confidence limits. RPA, Right pulmonary artery. LPA, Left pulmonary artery. *With or without segmental stenosis. tPRV/Lv as measured before patch perforation in six patients.

gression using the stepwise forward and backward elimination methods so that the relative importance of each variable vis-a-vis the other variables could be ascertained.17 Variables tested included age at operation, body surface area, diameter of the right, left, and main pulmonary arteries measured on angiocardiograms (normalized by using a ratio of each over the diameter of the descending aorta at the diaphragm), presence of segmental stenosis in each pulmonary artery, presence of abnormal arborization of each pulmonary artery, presence of large "bronchial" arteries, and preoperative hematocrit value. Variables with p < 0.15 were included in the final model. Survival and reoperation-free actuarial curves have been computed separately (by the method of Kaplan and Meier18) and compared for patients who had a valved external conduit and for those in whom a transannular patch was inserted or an infundibulectomy was done. Results Hospital mortality and its determinants. Thirteen (16 percent) of 80 patients died within 30 days of operation (Table II). Six patients died because of low cardiac output, five from severe pulmonary dysfunction, and one each from tachyarrhythmia and hemorrhagic diathesis. The hospital mortality rate in patients with congenital pulmonary atresia with confluent right and left pulmonary arteries was similar to that of patients with acquired pulmonary atresia (Table III). All three patients with nonconfluent right and left pulmonary arteries died (p = 0.0001 for comparison with mortality rates in the remaining patients). Three (38 patients) of eight patients operated upon before 4 years of age died, but the two patients less than 24 months of age (the youngest was 12 months old) at operation both survived (Table II). Ten (14 percent) of 72 patients 4 years of age or older (the oldest was 35

years old) at the time of operation died. Age at operation, considered as a continuous variable, is a weak determinant of hospital mortality (Fig. 1). However, when the most unfavorable group, those with nonconfluent 'fft and right pulmonary arteries, are excluded, the p value of this relation is 0.4. Thus there is no demonstrable relation between age and hospital mortality rate. The type of repair did not appear to influence the operative mortality rate (Table IV). Although the hospital mortality was higher in patients who received a valved external conduit compared with those who had a transannular patch, the p value for the difference in the group as a whole was 0.11. The p value was 0.26 when only the 59 patients with congenital pulmonary atresia and confluent right and left pulmonary arteries are considered. Four deaths (80 percent) occurred among five patients whose postrepair PRVILV was greater than 1, compared to nine deaths (12 percent) among the 75 patients in whom this ratio was less than 1 (Table V). This significant relation of postrepair PRV/LV to hospital mortality rate is also evident in the parametric analysis (Fig. 2). The probability of hospital death because of low cardiac output is even more strikingly determined by the postrepair PRV/LV (Fig. 3). Multiple nonlinear regression analysis of age at repair and PRV/LV indicates that PRV/LV is the important determinant of death (p = 0.017) rather than age at operation (p = 0.54). When the right and left pulmonary arteries were judged by review of data in the records to be very small, or one was absent, the hospital mortality rate was higher than when these arteries were normal or moderately small (Table VI). Also, the ratio of peak pressure in the right ventricle to that in the left (PRV/ LV) was higher. Determinants of PRV/LV after repair. Single regression analysis demonstrated a relationship to post-

The Journal of Thoracic and Cardiovascular Surgery

3 2 8 Alfieri et al.

Table VII. Combined variables related to postrepair PRVILV Coefficient

Variables Continuous variables RPA + LPA to descending aorta diameter ratio Body surface area (sq. M.) Categorical variables* Bilateral abnormality of pulmonary arterial arborization Stenosis at origin of RPA Abnormality of pulmonary arterial aborization to right lung exclusively

p Value

± S.E.

-0.33 ± 0.050 -0.12 ± 0.059

p < 0.0001 p = 0.05

0.85 ± 0.073 0.25 ± 0.074 0.22 ± 0.101

p < 0.0001 p = 0.0014 p = 0.03

Legend: RPA, Right pulmonary artery. LPA, Left pulmonary artery. *If present.

Table VIII. Repair of tetralogy of Fallot with pulmonary atresia and confluent right and left pulmonary arteries (1967-1978)* Catecholamine support No.

PRV/LV (mean ± S.D.)

Valved external conduit

38

Transannular patch

12

No.

%

0.60 ± 0.221

12

32

23%-41% 1

0.63 ± 0.186

0

0

0%-15% J

CL

P == 0.02 Legend: CL = 70 percent confidence limits. ♦Excluded patients who died during the operation (three) and those with the ventricular septal defect patch perforated (six).

Table IX. Repair of tetralogy of Fallot with pulmonary atresia (1967-1978)* Important

pulmonary

dysfunction Source of pulmonary blood

flow

Patients with large "bronchial" arteries Patients with other sources of pulmonary blood flow

CL

No.

No.

29

9

31

21 %-42%

43

5

12

7%-19%

Legend: CL = 70 percent confidence limits, p = 0.04. •Eight patients are excluded (see Methods).

repair PRV/LV of age at repair (r = - 0 . 3 8 , p = 0.004) and body surface area (r = —0.35, p = 0.007). It also demonstrated an important relationship to postrepair PRV/LV of the measurements on the preoperative angiocardiograms, including the ratio of right pulmonary artery diameter to descending aorta diameter (r = —0.54, p < 0.0001), the ratio of left pulmonary artery to descending aorta (r = - 0 . 5 4 , p < 0.0001), the sum of these two ratios (r = - 0 . 5 8 , p < 0.0001; Fig. 4), the presence of bilateral arborization abnormality of the pulmonary arteries (r = 0.78, p < 0.0001), arborization abnormality of the right pulmonary artery only (r = 0.69, p < 0.0001), arborization of the left pulmonary artery only (r = 0.56, p < 0.0001), and the

presence of large "bronchial" arteries (r = 0.36, p = 0.006). PRV/LV was not related to use of a valved external conduit or another method of outflow tract reconstruction (p = 0.5), to preoperative hematocrit value (p = 0.9), or to the diameter of the main pulmonary artery in patients in whom this was present (P = 0.7). Multiple regression analyses showed that a combination of certain variables was an important determinant of PRV/LV (Table VII). The equation for the calculation of PRV/LV from these variables is as follows: Postrepair

PRV/LV

= 1.16 — 0.33 •

(RPA/AO + LPA/AO diameter) -0.12 • BSA + 0.85lal + 0.25lbl + 0.22lcl where PRV/LV = ratio of systolic right ventricular pressure to that of the left; RPA and LPA = right and left pulmonary arteries; AO = aorta at diaphragm; BSA = body surface area. The [a] is added when bilateral abnormality of pulmonary artery arborization is present, [b] when stenosis at the origin of the right pulmonary artery is present, and [c] when the abnormality of only right pulmonary artery arborization is present. The standard error (70 percent confidence limits) of the estimated PRV/LV is 0.17. The relation of the calculated PRV/LV to that observed is shown in Fig. 5. The effect of the two continuous variables is shown in

Volume 76 Number 3 September, 1978

Tetralogy of Fallot with pulmonary atresia

32 9

l.o Bilateral Arborization Abnormalities

0.85*0.073

RPA Stenosis

0.25i0.074

Right Only Arborization Q 22*0 101 Abnormalities

RIGHT PA AO

LEFT PA AO

DIAMETER

Fig. 6. PRV/LV related to the sum of RPA/AO and LPA/AO for patients with various body surface areas (BSA), from the multiple regression equation. The standard error (70 percent confidence limits) of the estimated PRV/LV is ±0.17. The values to be added when bilateral arborization abnormalities, RPA stenosis, and right only arborization abnormalities are present are indicated in the figure. Fig. 6: (1) the sum of the ratios of diameter of the right pulmonary artery over that of the descending thoracic aorta plus the ratio of diameter of the left pulmonary artery to the aorta and (2) body surface area. Cardiac performance after repair. Twelve (32 percent) of 38 patients with congenital pulmonary atresia and confluent right and left pulmonary arteries repaired with a valved external conduit received catecholamine infusions after operation; by comparison, none (zero percent) of those receiving a transannular patch were so treated (Table VIII). The difference was similar in those patients operated upon before July, 1977, since which date cold cardioplegia and transannular patching have both been used more frequently. The PRV/LV was not significantly different following the two types of operations. Cold and cardioplegia were used for myocardial preservation in a group of patients in 1977. Their mean cardiac index 6 to 24 hours after operation (n = 7) was 2.8 L. • min. -1 • M." 2 ± 0.22, not significantly different from that of patients operated upon in 1976 using only cold (n = 9) (p = 0.33). Mean cardiac index in the first 6 postoperative hours was 2.5 ± 0.10(n = 8), higher (p = 0.14) than in those (n = 8) in whom only cold was used. Mean postoperative PRV/LV was similar in the two groups. Pulmonary dysfunction after repair. Important

pulmonary dysfunction (see Material and methods) occurred more often in patients with large "bronchial" arteries than in patients with other sources of pulmonary blood flow (Table IX). Ligation of large "bronchial" arteries did not prevent pulmonary dysfunction and resulted in one case in a fatal pulmonary infarction. The nine patients in whom large "bronchial" arteries have not been ligated did not have important pulmonary dysfunction or left atrial pressure above 15 mm. Hg postoperatively. Late results. Long-term survival of patients operated upon prior to Jan. 1, 1977, was not significantly different for the 29 traced patients who received a valved external conduit than for the 19 who had a transannular patch or an infundibulectomy (Fig. 7). The one late death in the latter group occurred unexpectedly 2 months postoperatively, presumably due to an arrhythmia, in a patient who was 19 months old at repair and immediately postoperatively had a PRV/LV of 0.65. One of the patients who received a valved external conduit died suddenly at home 27 months postoperatively; his age at repair was 16 years, and the PRV/LV immediately after repair was 0.80. Two other patients who received a valved external conduit died following reoperation for conduit obstruction. Incidence of reoperation in the two groups is shown by the reoperation-free actuarial curve in Fig. 8. Five of

The Journal of Thoracic and Cardiovascular Surgery

3 3 0 Alfieri et al.

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Fig. 7. Actuarial late survival for traced patients who received a valved external conduit and for those who had a transannular patch or an infundibulectomy. The numbers in parenthesis represent patients at risk. The 70 percent confidence limits (dotted lines) are overlapping throughout, indicating that probably the survival proportions for the two groups are actually similar. Table X. Palliative shunting operations for tetralogy ofFallot with pulmonary atresia (1967-1978) Total

Waterston

Blalock-Taussig Hospital deaths

Hospital deaths

Hospital deaths

Age (mo.)

No.

No.

%

CL

No.

No.

%

CL

No.

No.

%

CL

<3 >3 < 6 > 6 < 12 >12 < 24 >24

4 1 3 4 13

1

25 0 0 0 0

3%-63% 0%-86% 0%-47% 0%-38% 0%-14%

3 2 1

0 1

0 50 0

0%-47% 7%-93% 0%-86%

1 1

-

-

-

14 33 0 0 0

2%-4l% 4%-76% 0%-38% 0%-38% 0%-ll%

25

1

4

1%-13%

2

6

2%-I3%

Totals

-

1

-

7

1

0

0%-86%

1 3 4 4 16*

14

2%-4l%

34*

Legend: CL = 70 percent confidence limits. *lncludes two patients with other kinds of shunts.

the group of 29 traced patients receiving valved external conduits required reoperation 5 months to 6V2 years after the original repair because of conduit obstruction. No patient in the nonconduit group has required reoperation. The behavior of the two groups in this regard is significantly different after the fourth postoperative year. Forty (91 percent) of the 44 living traced patients have no symptoms, no restriction in activity, and no need for medication. Three (7 percent) patients, one of whom has absent left pulmonary artery, are mildly restricted in their activity and are taking digoxin. Only

one patient (2 percent) is severely incapacitated, taking digoxin and large doses of diuretics, 5 years postoperatively. The PRV/LV immediately after repair was 0.35. She had been without symptoms the first 3 postoperative years, was delivered of a normal child, and then became symptomatic. Recatheterization showed severe pulmonary hypertension, which is possibly the result of pulmonary emboli. Discussion Material and methods. All the patients included in this study had atrioventricular concordance, biventricu-

Volume 76 Number 3 September, 1978

Tetralogy of Fallot with pulmonary

atresia

3 31

TRANSANNULAR PATCH OR INFUNDIBULECTOMY(n = l9)

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YEARS AFTER OPERATION Fig. 8. Actuarial percent of traced hospital survivors who are reoperation free. The 70 percent confidence limits are also shown. The p value for the difference at 5 years is 0.06. lar origin of the aorta, a large VSD in a high (subaortic) position, and pulmonary atresia. Patients in whom the aorta originates entirely from the right ventricle are considered to have transposition of the great arteries or double-outlet right ventricle with pulmonary atresia and are excluded from this study. Although we 8 ' 19 have previously used the term "pseudotruncus arteriosus" to describe a subset of these patients, it is more generally acceptable to refer to this subset as those with confluent right and left pulmonary arteries. We acknowledge that, when the pulmonary trunk is entirely absent, and particularly when the right and left pulmonary arteries are nonconfluent, it is only an assumption that the pulmonary trunk would be over the right ventricle and that the phrase "tetralogy of Fallot" applies. Patients with presumably congenital pulmonary atresia and those in whom acquired pulmonary atresia developed after a previous shunting procedure are included in this analysis. This has been done also by others. 20 In part, we have done this to obtain a wide spectrum of sizes of right and left pulmonary arteries. During the period covered by the study, 40 additional patients with tetralogy of Fallot and pulmonary atresia underwent palliative operations, either a systemic-pulmonary artery shunt (Table X) or transannular outflow tract patching (or in one case insertion of a valved external conduit) without any attempt to repair the VSD (Table XI), because of young age or ex-

Table X I . Palliative transannular patching tetralogy of Fallot with pulmonary atresia (1967-1978)

<3 >3 < 6 >6 < 24 >24 Totals

for

-

-

-

-

1

20

3%-53%

6

2

33

12%-62%

1

5

1

100

14%-100%

Legend: CL = 70 percent confidence limits.

tremely small right and left pulmonary arteries.* The present study was one of patients subjected to intended complete repair. When the malformation was completely repaired and the VSD patch subsequently perforated, the patient was included in the present study. During this period, only those few patients with bilateral absence of pulmonary arteries (so-called truncus type IV) were denied some kind of operation. A limitation of this particular study is that the PRV/LV value used for the analysis was the one obtained in the operating room after completion of the repair. On the basis of other observations, we are aware *We are indebted to Dr. Claude Labrosse for collection and analysis of these data.

3 3 2 Alfieri et al.

that, although in general the PRV/LV remains approximately the same throughout the early postoperative period, it occasionally may increase or decrease significantly. We have elected to analyze some of our data by statistical methods more complex than the ones commonly used in the surgical literature, and to present some of the information by mathematical models. This is done in an effort to make the results of the study useful in managing individual patients in the future. Results. The age at the time of repair was not a determinant of hospital mortality rate when the patients with nonconfluent right and left pulmonary arteries were excluded. Danielson, Wallace, and McGoon20 reported a similar experience. Admittedly, few very young patients are included in either series. Although Barratt-Boyes21 has reported reasonably good results in infants (one death in five patients) using a homograft as the valved external conduit, we would advise a shunt and later repair in infants less than about 2 years of age unless it appeared nearly certain that transannular patching could be used. This experience recommends that a transannular patch be used whenever possible for correcting pulmonary atresia. Danielson and colleagues20 have expressed a similar opinion. A valved external conduit, we believe, should be employed only if the main pulmonary artery is absent or the left anterior descending coronary artery originates anomalously. Although the early and late mortality rates are not significantly different in patients who received a conduit and in those who did not, the reoperation-free proportion is significantly lower in the conduit group after the fourth postoperative year. Recently, moreover, the occurrence of significant gradients at the level of the valve and at the proximal and distal anastomoses has been demonstrated following conduit operations for a variety of congenital heart diseases.22 We realize that Ross and Somerville23, 24 and Radley-Smith, Ahmed, and Yacoub25 have reported excellent long-term results using homografts as valved external conduits. We acknowledge that fresh, antibiotic-sterilized homografts may give better results than heterograft-valved or homograft-valved Dacron conduits. However, homografts are difficult to procure in sufficient numbers in many parts of the world, including our own. Our follow-up data, as well as data from others, 26-28 show that pulmonary insufficiency resulting from a transannular patch is well tolerated by these patients, at least for periods up to about 10 years. Unexpectedly, we found that at comparable levels of PRV/LV a consider-

The Journal of Thoracic and Cardiovascular Surgery

able number of patients with conduits exhibited the need for catecholamine support, whereas no patient with a transannular patch did so. This is difficult to interpret but certainly confirms that the pulmonary insufficiency which develops acutely after placement of a transannular patch is well tolerated initially. We have not been able to demonstrate any significant improvement in cardiac performance after cold cardioplegic myocardial preservation but believe this is a valuable adjunct to the operative technique. Therefore, we recommend its use. The degree of immediate residual right ventricular hypertension is shown by this study to be the most important determinant of hospital mortality. In turn, it was determined by the size, configuration, and arborization of the right and left pulmonary arteries. Therefore, a method of predicting postrepair PRV/LV before the operation would be of obvious value, for it would allow a planned initial palliative operation when this ratio is predicted to be too high. We followed the suggestion of McGoon, Baird, and Davis9 and retrospectively compared the size of the right and left pulmonary arteries with that of the aorta at the diaphragm. We found it important to refine this relationship by developing quantitative interrelations among these and other variables. The equation which we developed gives a PRV/LV within 0.17 of that actually observed in 70 percent of the instances in this study. We recommend its use prospectively, not only in tetralogy of Fallot with pulmonary atresia but in other similar situations. Either the equation given previously or the nomogram (Fig. 6) should be used, adding [a], [b], and [c] when indicated. The assumption in using the equation prospectively should be that there will be little gradient between the right ventricle and pulmonary arteries. In recommending this technique to assess operability preoperatively, we concede that we do not know the precise value of postrepair PRV/LV which is "too high" for initial complete repair. Certainly, one greater than 1 exposes the patient to a high risk, and we believe an initial palliative operation is indicated for patients in whom this is predicted. In many patients the palliative operation causes small pulmonary arteries to enlarge and thereby permits eventual complete repair.29- 30 Also, if pulmonary artery arborization anomalies are thought to be present, they can be better studied angiographically after the palliative procedure. When the PRV/LV is predicted to be high but less than 1, the decision for or against repair is more difficult. In infants, it probably is prudent to do a preliminary pallia-

Volume 76 Number 3 September, 1978

tive anastomotic operation if the predicted value is greater than about 0.65. We now accept older children and young adults for complete repair if the predicted value is less than about 0.85. If one does a complete repair and, after discontinuing bypass, measures a PRV/LV greater than 1, we believe that bypass should be re-established and the VSD patch perforated. At least, PRV/LV cannot than be greater than 1. Another serious problem after repair of this malformation has been pulmonary dysfunction. Mortality and morbidity from pulmonary dysfunction may be less if ligation of "bronchial" arteries is avoided. A fatal pulmonary infarction occurred in one of our patients following ligation of a large "bronchial" artery, and a similar case has also been reported by Danielson and associates. 20 On the other hand, failure to control flow through large "bronchial" arteries has been thought to result in excessive intracardiac return of blood, overdistention of the heart, flooding of the surgical field, and underperfusion of the patient during the operation. 9 This has not been our experience when appropriate precautions are taken. Also, serious hemodynamic complications in the postoperative period have been suggested as a consequence of a large left-to-right shunt through "bronchial" arteries left open. 9 , 3 1 We did not have hemodynamically significant left-to-right shunt postoperatively in our patients in whom large "bronchial" arteries were not ligated. However, they probably should be closed if they enter directly into the main left and right pulmonary arteries or if, preoperatively, pulmonary blood flow (through these collaterals) was considerably greater than systemic blood flow.

REFERENCES 1 Lillehei CW, Cohen M, Warden HE, Read RC, DeWall RA, Aust JB, Varco RL: Direct vision intracardiac surgery by means of controlled cross circulation for correction of ventricular septal defects, atrioventricularis communis, isolated infundibular pulmonic stenosis, and tetralogy of Fallot, Proc Henry Ford Hospital Symposium, Philadelphia, 1955, W. B. Saunders Company, pp 371-392 2 Kirklin JW, Payne WS: Surgical treatment for tetralogy of Fallot after previous anastomosis of systemic to pulmonary artery. Surg Gynecol Obstet 110:707-713, 1960 3 Kirklin JW, Devloo RA; Hypothermic perfusion and circulatory arrest for surgical correction of tetralogy of Fallot with previously constructed Potts' anastomosis. Chest 39:87-91, 1961 4 Ebert PA, Gay WA Jr, Oldham HN: Management of aorta-right pulmonary artery anastomosis during total

Tetralogy of Fallot with pulmonary atresia

5

6

7

8

9 10

33 3

correction of tetralogy of Fallot. Surgery 71:231-234, 1972 Kirklin JW, Silver AW: Technic of exposing the ductus arteriosus prior to establishing extracorporeal circulation. Proc Staff Meet Mayo Clin 33:423-425, 1958 Rastelli GC, Ongley PA, Davis GD, Kirklin JW: Surgical repair for pulmonary valve atresia with coronarypulmonary artery fistula. Report of case. Mayo Clin Proc 40:521-527, 1965 Krongrad E, Ritter DG, Hawe A, Kincaid OW, McGoon DC: Pulmonary atresia or severe stenosis and coronary artery-to-pulmonary artery fistula. Circulation 46:10051012, 1972 Doty DB, Kouchoukos NT, Kirklin JW, Barcia A, Bargeron LM Jr: Surgery for pseudotruncus arteriosus with pulmonary blood flow originating from upper descending thoracic aorta. Circulation 45, 46:Suppl 1:121-129, 1972 McGoon DC, Baird DK, Davis GD: Surgical management of large bronchial collateral arteries with pulmonary stenosis or atresia. Circulation 52:109-1 18, 1975 Kouchoukos NT, Barcia A, Bargeron LM, Kirklin JW: Surgical treatment of congenital pulmonary atresia with ventricular septal defect. J THORAC CARDIOVASC SURG

61:70-84, 1971 11 Bowman FO, Hancock WD, Malm JR: A valve-containing Dacron prosthesis. Arch Surg 107:724-728, 1973 12 Bailey WW, Kirklin JW, Bargeron LM Jr, Pacifico AD, Kouchoukos NT: Late results with synthetic valved external conduits from venous ventricle to pulmonary arteries. Circulation 56:Suppl 2:73-79, 1977 13 Pacifico AD, Kirklin JW, Blackstone EH: Surgical management of pulmonary stenosis in tetralogy of Fallot. J THORAC CARDIOVASC SURG 74:382-395, 1977

14 Parr GVS, Blackstone EH, Kirklin JW: Cardiac performance and mortality early after intracardiac surgery in infants and young children. Circulation 51:867-874, 1975 15 Blackstone EH, Kirklin JW, Pluth JR, Turner ME, Parr GVS: The performance of the Braunwald-Cutter aortic prosthetic valve. Ann Thorac Surg 23:302-318, 1977 16 Walker SH, Duncan BB: Estimation of the probability of an event as a function of several independent variables. Biometrika 54:167-179, 1967 17 Barr AJ, Goodnight JH, Sail JP, Helwig JT: A User's Guide to Statistical Analysis System 1976, Raleigh, 1976, Sparks Press, pp 251-256 18 Kaplan EL, Meier P: Non-parametric estimation from incomplete observations. J Am Stat Assoc 53:457-482, 1958 19 Pacifico AD, Kirklin JW, Bargeron LM Jr, Soto B: Surgical treatment of common arterial trunk with pseudotruncus arteriosus. Circulation 49, 50:Suppl 2:20-26, 1974 20 Danielson GK, Wallace RB, McGoon DC: Pulmonary atresia: Surgical considerations and results of definitive repair. Third Joint US-USSR Symposium on Congenital Heart Disease, 1977, in press

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Alfieri et al.

21 Barratt-Boyes BG: Primary definitive intracardiac operations in infants. Tetralogy of Fallot, Advances in Cardiovascular Surgery, JW Kirklin, ed., New York, 1973, Grune & Stratton, Inc., pp 155-169 22 Norwood WI, Freed MD, Rochini AP, Bernhard WF, Castaneda AR: Experience with valved conduits for congenital heart disease. Ann Thorac Surg 24:223-232, 1977 23 Ross DN, Somerville J: Correction of pulmonary atresia with a homograft aortic valve. Lancet 2:1446-1447, 1966 24 Ross D, Somerville J: Homograft reconstruction of right ventricular outflow tract in pulmonary atresia. Late results (abstr). Br Heart J 38:316, 1976 25 Radley-Smith R, Ahmed M, Yacoub M: Late results of aortic homograft reconstruction of the right ventricular outflow tract in infants and children. Thoraxchirurgie 23:455-459, 1975 26 Nemickas R, Roberts J, Gunnar RM, Tobin JR Jr: Isolated congenital pulmonary insufficiency. Differentiation of mild and severe form. Am J Cardiol 14:456-463, 1964 27 Collins NP, Braunwald E, Morrow AG: Isolated congenital pulmonic valvular regurgitation. Diagnosis by cardiac catheterization and angiocardiography. Am J Med 28: 159-164, 1960 28 Gotsman MS, Beck W, Barnard CN, O'Donovan TG, Schrire V: Results of repair of tetralogy of Fallot. Circulation 40:803-821, 1969 29 Gill CC, Moodie DS, McGoon DC: Staged surgical management of pulmonary atresia with diminutive pulmonary arteries. J THORAC CARDIOVASC SURG 73:436-442, 1977

30 Kirklin JW, Bargeron LM Jr, Pacifico AD: The enlargement of small pulmonary arteries by preliminary palliative operations. Circulation 56:612-617, 1977 31 Barratt-Boyes BG: The surgery of tetralogy, pulmonary atresia with ventricular septal defect, and transposition of the great vessels. Aust Radiol 12:311-319, 1968 Discussion DR. R O B E R T J .

SZARNICKI

San Francisco, Calif.

The authors are to be complimented on their presentation and their results in this challenging group of patients. I would like to address the problem of postoperative pulmonary dysfunction in patients with large systemic-pulmonary artery collaterals, to which the authors have alluded. Persistent patency of these vessels in spite of efforts to obliterate them at the time of intracardiac repair is a recognized cause of postoperative pulmonary problems and congestive heart failure, which may be a significant contributing factor in some of the deaths encountered in this group. Occasionally, further operations must be contemplated to control pulmonary overcirculation in these already compromised patients if they are to survive. I would like to describe briefly a technique for obliteration of persistent large aorta-pulmonary collaterals which we employed successfully at Pacific Medical Center in a young man

who underwent correction of severe pulmonary atresia. Large collaterals arose from the left coronary system, both subclavian vessels, the thoracic aorta, and the right thyrocervical trunk. Six large vessels were ligated at the time of intracardiac repair, which was uneventful, with short periods of circulatory arrest being used to provide adequate exposure. His postoperative course was complicated by severe congestive heart failure, and he eventually required tracheostomy for continued ventilatory support. One month after the operation, he was taken to the catheterization laboratory to define the anatomy of the residual collateral vessels. After selective angiograms were completed, helical wire coils with an attached tuft of wool were introduced via a No. 7 Fr. catheter into the femoral artery and were positioned in the orifice of the collateral vessels. The helix is supplied in a Teflon sleeve that permits introduction into the cardiac catheter, which has been positioned in the collateral vessel. A Teflon-coated guidewire then is used to advance the coil, which assumes a helical configuration as it is extruded from the catheter tip. Complete occlusion of six large vessels by this technique was later demonstrated by injection of contrast material. There was marked improvement in the patient's clinical state, and within 72 hours he was able to be weaned from the ventilator. He remains well 7 months after the operation, although he requires daily digitalis and diuretics. The chest x-ray film, although improved, continues to show persistent pulmonary overcirculation and cardiomegaly. Elective recatheterization and selective angiography are planned in the near future, and further embolization of persistent aorta-pulmonary collaterals is planned. This technique has been successful in the management of arteriovenous malformations in the central nervous system as well as in the control of hemorrhage from duodenal ulcer and abdominal neoplasms. Its use in congenital heart disease has not been previously explored. The procedure permits precise localization and avoids the risk of distal embolization and recanalization, which are known to occur with other techniques using autologous blood clot, muscle, Gelfoam, and tissue adhesives. Although indications for use of this technique are limited, its application in children with large aorta-pulmonary collaterals and other systemic-pulmonary artery shunts warrants further consideration and evaluation. I wonder if the authors could describe for us their current techniques of managing patients who remain in congestive heart failure with documented persistent aorta-pulmonary collaterals following repair of congenital heart defects. DR. PAUL A. E B E R T San Francisco, Calif.

We agree entirely with Dr. Alfieri that, whenever possible, the outflow tract should be patched. I am interested in your approach to infants in whom the diagnosis of pulmonary atresia and tetralogy anomaly is made in the first month of life. The main question in these patients

Volume 76 Number 3 September, 1978

is how to get a large enough pulmonary artery so that, ultimately, a patch can be placed across the outflow tract and the right ventricular pressure will be low enough. We feel it is very important to document in infancy, if possible, when the ductus is open, whether or not a main pulmonary artery is present. If such a pulmonary artery is present, then the possibility of doing a palliative outflow tract patch operation alone seems reasonable in many of these infants with very small pulmonary arteries. In our experience, this has been the

Tetralogy of Fallot with pulmonary atresia

335

best way to obtain enlargement of the pulmonary artery so that we could subsequently close the VSD and have a fairly low right-sided pressure afterward. D R . A L F I E R I (Closing) We thank Dr. Szarnicki and Dr. Ebert for their helpful discussion. We agree with Dr. Ebert as to the merits of transannular patching as an initial palliative operation.

Information for authors Most of the provisions of the Copyright Act of 1976 became effective on January 1, 1978. Therefore, all manuscripts must be accompanied by the following statement, signed by each author: " T h e undersigned author(s) transfers all copyright ownership of the manuscript entitled (title of article) to The C. V. Mosby Company in the event the work is published. The author(s) warrants that the article is original, is not under consideration by another journal, and has not been previously published." Authors will be consulted, when possible, regarding republication of their material.