The influence of pulmonary artery banding on outcome after the Fontan operation

The influence of pulmonary artery banding on outcome after the Fontan operation Thirty-eight patients were selected from a total of 120 patients who underwent the Fontan operation between 1974 and 1988. They were classified into two groups. Group 1 consisted of 18 patients with previous pulmonary artery banding at a mean age of 7 months (2 days to 59 months), and group 2 comprised 20 patients with native pulmonary stenosis. In group 1, 10 children had tricuspid atresia (seven with normally connected and three with transposed great arteries), six had double-inlet ventricle, and two had complex heart malformations. Group 2 consisted of 12 patients with tricuspid atresia and normaUy connected great arteries, six with double-inlet ventricle, and two with complex malformations. The foUowing clinical and hemodynamic parameters at cardiac catheterization and cineangiocardiography were determined in both groups before the Fontan operation: age and body surface area, hemoglobin concentration and hematocrit value, atrial and pulmonary artery pressures, end-diastolic pressure of the systemic ventricle, arterial oxygen saturation, pulmonary j systemic flow ratio, enddiastolic volume, ejection fraction and mass of the systemic ventricle, cardiac index, and Nakata index. After the Fontan operation in aU patients, the presence or absence of pericardial and pleural effusions, ascites, protein-losing enteropathy, and liver and kidney dysfunction was assessed and the clinical status was classified according to New York Heart Association criteria. AU preoperative and postoperative parameters were tested for differences between the two groups, and they were compared with normal values. Hematocrit value was higher in group 2 than in group 1 (57.8 % versus 53.1 %; p < 0.05). Ventricular mass index was increased in group 1 when compared with group 2 (125.8 gmjm2 versus 87 gmjm2; p < 0.05). Severe pericardial effusions in the early postoperative period were significantly more frequent in group 1 and were particularly prevalent in the subgroup with longstanding pulmonary artery banding (p < 0.01). Subaortic stenosis was observed more frequently in group 1. The remaining parameters were not statisticaUy different between the two groups. We conclude that the significant increment in ventricular mass after pulmonary artery banding may represent a risk for unfavorable outcome after the Fontan operation, which increases with time. Therefore, long-standing pulmonary artery banding as a palliative procedure for candidates for the Fontan operation should be avoided. (J THORAC CARDIOVASC SURG 1992;104:743-7)

I. Maleic, MD, * U. Sauer, MD, H. Stern, MD, M. Kellerer, MD, B. Kiihlein, MD, D. Locher, MD, K. Biihlmeyer, MD, and F. Sebening, MD, Munich, Germany

Since Choussat and Fontan and their coworkers I first published their selection criteria for the Fontan operation, several of these criteria have been altered.v 3 and others, From the Departments of Pediatric Cardiology and Surgery, Deutsches Herzzentrum Miinchen, Miinchen, Germany. Received for publication Sept. 14, 1990. Accepted for publication Aug. 7,1991. Address for reprints: I. Maleic, MD, Pediatric Clinic Rebro, Department of Cardiology, Kispaticeva 12,41000 Zagreb, Yugoslavia. *Research fellow of the Humboldt-Stiftung from 1987 to 1988.

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such as the pulmonary artery index, as espoused by Nakata and associates," have been added. During past years ventricular mass has been the subject of great interest as a determinant factor for outcome after the Fontan operation.>" It has been suggested that severe hypertrophy of the systemic ventricle develops in patients who have had pulmonary artery banding (PAB) before the Fontan operation.f Furthermore, hypertrophy of the systemic ventricle affects diastolic ventricular function, with a negative influence on atrioventricular (AV) valve function and a passive increase in pulmonary vascular and right atrial pressure. Markedly elevated systemic venous

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Table I. Study group (38/120 patients after modified

Fontan operation between July 1974 and July 1988) Group 2 (20/38 patients with PS)

Group I (18/38 patients with PAB) Class

No.

Class

No.

TAl C TA II C DIY CHM

7/18 3/18 6/18 2/18

TAl B DIY CHM

12/20 6/20 2/20

Patients with tricuspid atresia were classified in accordance with the classification of Edwards and Burchell." PAB, Pulmonary artery banding; PS, pulmonary stenosis; TA, Tricuspid atresia; DIV, double-inlet ventricle; CHM, complex heart malformation.

pressure, however, seems to trigger pleural and pericardial effusions and ascites in the postoperative course of the Fontan operation. Therefore, in this retrospective study we investigated whether the clinical and angiocardiographic findings before the Fontan operation are different in patients with P AB and pulmonary stenosis. In addition, the influence of PAB on the prevalence of postoperative complications and perioperative mortality after the Fontan operation was assessed.

Patients and methods Patients (Table 1). Between July 1974 and July 1988, a total of 120 patients underwent the Fontan operation at a mean age of 8.9 years (0.4 to 26) in our institution. Sixty-nine (57.5%) of them had tricuspid atresia, 34 (28.3%) double-inlet ventricle, and 17 (I 4.2%) complex heart malformations. Eighteen ofthese 120 children had previous PAB at a mean age of 207 days (2 days to 59 months), and they formed group 1. Twenty agematched patients with valvular or subvalvular pulmonary stenosis were included as a control group (group 2). Group 1 comprised 10 children with tricuspid atresia (seven with normally connected and three with transposed great arteries), six with double-inlet ventricle, and two with complex heart malformations. Of the six patients with double-inlet ventricle, five had a left ventricular and one an undetermined ventricular morphology. Group 2 consisted of 12 children with tricuspid atresia with normally connected great arteries, six with double-inlet ventricle, and two with complex heart malformations. Of the six patients with double-inlet ventricle, four had a left ventricular and two a right ventricular morphology. Ofthe two patients with complex heart malformations, one had hypoplastic right ventricle and tricuspid valve and the other pulmonary atresia with intact ventricular septum and hypoplastic right ventricle. Thus 15 patients of group 2 had a single AV valve and five had two A V valves. The fivepatients with two AV valvescomprised three with double-inlet ventricle and two with complex heart malformations. Differences in diagnoses between group 1 and the control group consisted mainly in a higher prevalence of transposed arteries in patients with tricuspid atresia in group 1. In the total group of 120 patients who had a Fontan operation, there were only five who had tricuspid atresia with transposed great art-

eries and pulmonary stenosis. Because of inappropriate age, they were not included in the control group. The median age at the Fontan operation was 8.1 years (3 to 20) in group 1 and 8.6 years (0.6 to 21.6) in group 2. In group 1 the only palliative procedure was PAB. In group 2 eight patients had no palliative operation before the Fontan operation (two with tricuspid atresia and normally connected great arteries and six with double-inlet ventricle). In the remaining 12 patients various palliative operations before the Fontan operation were performed to improve pulmonary blood flow,concurrent with pericardiotomy in five patients. They comprised unilateral or bilateral Blalock-Taussig shunt in seven patients with tricuspid atresia and normally connected great arteries, Waterston anastomosis in three patients (one with tricuspid atresia and normally connected arteries and two with complex heart malformations), and right ventricular outflow enlargement alone in one and combined with right Blalock-Taussig shunt and Waterston anastomosis in another patient with tricuspid atresia and normally connected arteries. Methods. During cardiac catheterization, which preceded the Fontan operation, the following parameters were determined in all patients: hematocrit value and hemoglobin concentration, mean right atrial pressure, mean pulmonary artery pressure, pulmonary vascular resistance, left ventricular enddiastolic pressure, heart rate, and the presence or absence of subaortic stenosis, determined by angiocardiographic examination. Cineangiocardiographic computer-assisted volume determinations of the systemic ventricle at end-diastole and end-systole were obtained by means of Simpson's rule. to End-diastolic and end-systolic volume were used for calculation of stroke volume and ejection fraction. Total cardiac output was determined by multiplying stroke volume by heart rate. In addition, ventricular mass was calculated as previously reported by Graham and coworkers. I I Cardiac output, end-diastolic volume, and ventricular mass were corrected for body surface area, and the ratio of ventricular mass to end-diastolic volume was calculated (mass/volume ratio). Cross-sectional areas of both pulmonary arteries were determined angiographically and corrected for body surface area," Normal values for the different angiocardiographically determined volumes were taken from the literature. I I, 12 To analyze the influence on ventricular mass of the time interval between PAB and the Fontan operation, we divided group 1 into two subgroups: group la with short-term intervals (i.e., <5.5 years) and group 1b with mid-term (i.e., >5.5 years) intervals to the Fontan operation (see Table VI). Presence or absence of subaortic stenosis was assessed, and AV valve insufficiency estimate was graded as minimal, moderate, or severe. Postoperative follow-up. All patients in groups 1 and 2 were examined clinically at 0.6 to 5 years (mean 2.7 years) and 0.2 to 6.4 years (mean 3.6 years), respectively, after the Fontan operation. Postoperative survival, presence or absence of protein-losing enteropathy, and chronic effusions (pleural, pericardial, ascites) were analyzed. The pleural and pericardial effusions were diagnosed by chest x-ray and echocardiographic examination. The diagnosis of protein-losing enteropathy was made exclusively on the basis of low serum protein levels in the absence of severe hepatic or renal disorder. Liver and kidney function tests included the determination of serum concentrations of aspartate aminotransferase, alanine aminotransferase, creatinine, and urea, respectively. Statistics. Differences for all parameters between groups 1

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Table II. Descriptive statistics for groups 1 and 2 and Student's t test analysis between the two groups (independent samples) Group I (PAS) Hemoglobin (g/L) Hematocrit (vol %) RAP (rnrn Hg) PAP (mm Hg) PVR (Em 2) EDP (rnm Hg) EDVI (ml/rrr') EF(%) CI (Lyrnin per square meter) VMI (grn/rrr') Mass/volume ratio Nakata index (mm 2/m2) Qp/Qs

Group 2 (PO)

Mean

SD

Mean

SD

p Value

16.9 53.1 7 15.3 2.17 8.7 233.0 52 7.6 125.8 0.69 316 0.99

3.1 8 3.6 4.8 0.76 5.1 135.9 5.8 4.1 58.7 0.26 161 0.46

19.7 57.8 7.5 13.5 1.8 6.6 193.8 55 7 87 0.61 269 0.87

2.5 7.5 6.9 4.8 0.9 3 134.0 5.6 3.4 47 0.39 137 0.40

P < 0.005 P < 0.05 NS NS NS NS NS NS NS p < 0.05 NS NS NS

PH, Pulmonary artery banding; PO, palliative operation; SD, standard deviation; RAP, mean right atrial pressure; PAP, mean pulmonary artery pressure; PVR, pulmonary vascular resistance; EDP, end-diastolic pressure; EDVI, end-diastolic volume index; EF, ejection fraction; CI, cardiac index; VMI, ventricular mass index; NS, not significant; Qp/Qs, pulmonary/systemic flow ratio.

Table III. Ventricular mass index (VMI) in groups 1 and 2, compared with each other and with normal values'" lJ Group

VMI (gm/m 2)

Group 1 vs group 2 Group 1 vs normal Group 2 vs normal

125.8 ± 58.7 vs 87.0 ± 47.0 125.8 ± 58.7 vs 86.0 ± 11.0 87.0 ± 47.0 vs 86.0 ± 11.0

Table IV. The prevalence ofsubaortic stenosis and AV valve insufficiency at last catheterization before Fontan operation in groups 1 and 2

p Value

No. ofpatients

p < 0.05

P < 0.005 NS

Group I Subaortic stenosis AV valve insufficiency

Group 2

5

0

5

0

p Value p

< 0.05

P < 0.05

Valuesare expressed as mean ± standard deviation. NS, Not significant.

and 2 wereassessed byStudent's t test for numericdata, x 2, and Fisher's exact test for categoric parameters. In addition, ventricularvolume indices in our studygroup werecomparedwith normal" and ventricular mass, and mass to volume ratio was compared between subgroups Ia and Ib by meansof Student's t test. Differences wereconsidered significant if the probability of error was equal to or less than 5% (p < 0.05).

Results Hematocrit value was significantly elevated in group 2 when compared with group I (57.8% versus 53.1%; p < 0.05) (Table II). Mean end-diastolic volume index was not significantly different in groups I and 2 (233 ml/rn? versus 193.8 ml/rn'') (Table II). There was, however, a significant difference in mean ventricular mass index between groups I and 2 (125.8 versus 87.0 gm/rrr'; p < 0.05) (Table II). Mean ventricular mass index was different from normal in group 1 (p < 0.005), but not in group 2 (Table III). Mass to volume ratios were similar in the two groups (0.69 ± 0.26 versus 0.61 ± 0.39). The prevalence of subaortic stenosis and AV valve insufficiency was distinctly different between groups I

and 2 (p < 0.01): Five of 18 children in group I had subaortic stenosis, and AV valve insufficiency developed in five patients-minimal in three and moderately severe in two. None of these findings was noted in group 2 (Table IV). Besides, there was a tendency to increased end-diastolic volume index and decreased mass to volume ratio (p < 0.07) in group 1, but these differences did not gain statistical significance (Table V). Subaortic stenosis was treated by a Damus-Stansel-Kaye procedure in two of fivepatients. 19-23Increment in ventricular mass index was greater in the children with mid-term PAB (group Ib) than in children with short-term PAB (group la) (p < 0.06). The difference in ventricular mass index between patients with mid-term PAB (group Ib) and those having normal values was highly significant (p < 0.005). In contrast, the difference in ventricular mass index between children with short-term PAB (group Ia) and those having normal values was not significant (Table VI). Pericardial effusions, which necessitated drainage during the early postoperative period (i.e., I month after

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Table V. EDVI, VMI, and mass volume ratio in patients with PAB (group I) before Fontan operation, subdivided according to presence or absence of subaortic stenosis Group I

EDVI (ml/rn-) VMI (grn") Mass/volume ratio

Table VII. In-hospital occurring effusions necessitating drainage in groups 1 and 2 Effusions Pleural PericardiaI

With subaortic stenosis

Without subaortic stenosis

274.6 ± 126.4 132.2 ± 52.0 0.57 ± 0.30

215.7 ± 141.2 116.4 ± 60.2 0.70 ± 0.26

NS NS NS

Table VI. Differences in ventricular mass index (VMI) between the groups with short-term (group I a) and mid-term (group Ib) PAB Group la vs group Ib Group Ib vs normal Group la vs normal

Group 2

p Value

10/18 (60%) 9/18 (50%)

8/20 (40%) 2/20 (10%)

NS p
NS, Not significant.

Table VIII. Prevalence of complications during the total postoperative follow-up in groups 1 and 2

Values are expressed as mean ± standard deviation. ED VI, End-diastolic volume index; VMI, ventricular mass index; PAR, pulmonary artery banding; NS, not significant.

Group

Group I

p Value

90.2 ± 46.0 vs 143.7 ± 57.6 p < 0.06 143.7 ± 46.0 vs 86.0 ± 11.0 p < 0.005 90.2 ± 46.0 vs 86.0 ± 11.0 NS

Group characteristics were as follows:Group Ia: interval PAB-Fontan operation <5.5 years (N = 6); Group Ib: interval PAB-Fontan operation >5.5 years (N = 12). Values are expressed as mean ± standard deviation. Both subgroups were compared with each other and with normal values. 10. II NS, Not significant.

operation), were more frequent in group 1 than in group 2 (p < 0.01). However, the prevalence of severe pleural effusions was not different in the two groups (Table VII). A significant difference was also observed in the occurrence of severe pericardial effusions in patients with short-term and mid-term PAB 0/6 in group la versus 8/12 in group 1b; p < 0.05). During the total postoperative period there was a tendency toward a greater prevalence of chronic effusions in group I than in group 2 (p < 0.08). There was no difference between the two groups regarding the occurrence of protein-losing enteropathy and survival (Table VIII). Reoperation was necessary in two patients. In one patient a residual interatrial defect was closed. In another patient rethoracotomy was performed because of hemorrhage in the early postoperative period.

Discussion In this study it could be demonstrated that in patients with PAB the ventricular mass index and the prevalence of subaortic stenosis and AV valve insufficiency are significantly greater than in patients with native pulmonary stenosis. From this experience it can be concluded that the addition of pressure load by PAB in volume-loaded ventricles, compared with naturally occurring outflow tract obstruction, seems to result in incremental ventricular

Group I Group l a

Group l b

Group 2

p Value

Protein-losing

2/6

3/12

4/20

NS

enteropathy Effusions Early death Late death

5/6 1/6 1/6

8/12 1/12 3/12

9/20 5/20 3/20

p

< 0.08 NS NS

Mean follow-up time in groups 1 and 2 was 2.7 years (0.6 to 5) and 3.6 years (0.2 to 6.4), respectively. Indicated are the number of patients for each subgroup. defined as in table VI. NS, Not significant.

hypertrophy. Hypertrophy favors the development of subaortic stenosis in the former group, and this in turn adds to the pressure load. Subaortic stenosis develops preferentially in patients with DIVs of the left ventricular type and subaortic right ventricular outlet chamber. It seems consistent that AV valve insufficiency is also related to the conspicuous pressure load and hypertrophy after PAB. Our observation of significant increase in ventricular mass and the development of subaortic stenosis is in agreement with previous reports.S 8,13-15 Despite a similar degree of pulmonary obstruction caused by PAB or native stenosis, as evidenced by comparable pulmonary artery pressure, patients with native stenosis in concurrence with a lesser degree of ventricular hypertrophy had higher hemoglobin and hematocrit levels than patients after PAB. There is much evidence that ventricular mass strongly affects the circulation after the Fontan operation. Effusions occurred more frequently and lasted longer in our patients with increased ventricular mass after longstanding PAB before the Fontan operation. In this specific group of patients, other investigators also reported not only a greater prevalence of postoperative complications, which included effusions, but also a significantly increased risk of death after the Fontan operation.v" Increase in ventricular mass, however, leads to a reduction of ventricular compliance, which impairs diastolic ventricular function. Compromised compliance and the presence of AV valve insufficiency and subaortic stenosis have all been reported to influence the course unfavorably after the Fontan operation. 5, 8, 16-18 Our patients with

Volume 104 Number 3 September 1992

PAB before the Fontan operation had a higher ventricular mass index than did patients with naturally occurring pulmonary stenosis. They also had more frequent and longer-standing effusions. The duration of PAB also played an important role because it correlated positively with the degree of ventricular mass increment and the prevalence of severe pericardial effusions. Our data suggest that the duration of P AB plays an important role in the increase of ventricular mass. Thus, considering our data, we believe it is advisable to avoid long-standing PAB in candidates for the Fontan operation. Depending on the underlying anatomy, alternative procedures have to be taken into consideration. These comprise, preferentially in patients with double-inlet ventricle ofthe left ventricular type and subaortic right ventricular outlet chamber, surgical relief of subaortic obstruction or a Damus-Stansel-Kaye anastomosis'Pt" between the divided pulmonary trunk and the ascending aorta, with the addition of a systemic-pulmonary artery shunt of distinct diameter or a bidirectional Glenn shunt. 22-26 REFERENCES 1. Choussat A, Fontan F, Besse P, Vallot F, Chauve A, Bricaud H. Selection criteria for Fontan procedure. In: Anderson RH, Shineborn EA, eds. Pediatric cardiology 1977. Edinburgh: Churchill Livingstone, 1978:559-66. 2. Mayer JE, Helgason H, Jonas RA, et al. Extending the limits for modified Fontan procedures. J THORAC CARDIOVASC SURG 1986;92:1021-8. 3. Coles JG, Kielmanowicz S, Freedom RM, et al. Surgical experience with the modified Fontan procedure. Circulation 1987;76(Pt 2):III61-6. 4. Nakata S, Imai Y, Takanashi Y, et al. A new method for the quantitative standardization of cross-sectional areas of the pulmonary arteries in congenital heart diseases with decreased pulmonary blood flow. J THORAC CARDlOVASC SURG 1984;88:610-9. 5. Kirklin JK, Blackstone EH, Kirklin JW, Pacifico AD, Bargeron LM. The Fontan operation: ventricular hypertrophy, age, and date of operation as risk factors. J THORAC CARDIOVASC SURG 1986;92:1049-64. 6. Rothman A, Lang P, Lock JE, Jonas RA, Mayer JE, Castaneda AR. Surgical management of subaortic obstruction in singleleft ventricle and tricuspid atresia. J Am Coll CardioI1987;10:421-6. 7. Newfeld EA, Nikaidoh H. Surgical management of subaortic stenosisin patients with single ventricle and transposition of the great vessels. Circulation 1987;76(Pt 2):III2933. 8. Freedom RM, Benson LN, Smallhorn JF, Williams WG, Trusler GA, Rowe RD. Subaortic stenosis, the univentricular heart, and banding of the pulmonary artery: an analysis of the courses of 43 patients with univentricular heart

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palliated by pulmonary artery banding. Circulation 1986; 73:758-64. 9. Edwards JE, Burchell HB. Congenital tricuspid atresia: a classification. Med Clin North Am 1949;33:1177-96. 10. Rackley CE, Dodge HT, Coble YD, Hay RE. A method for determining left ventricular mass in man. Circulation 1964;29:666-71. 11. Graham TP, Jarmakani JM, Canent RV, Marrow MN. Left heart volume estimation in infancy and childhood. Circulation 1971;43:895-904. 12. Nakazawa M, Marks RA, Isabel-Jones J, Jarmakani JM. Right and left ventricular volume characteristics in children with pulmonary stenosis and intact ventricular septum. Circulation 1976;53:884-90. 13. Sa no T, Ogawa M, Yabuuchi H, et al. Quantitative cineangiographic analysis of ventricular volume and mass in patients with single ventricle: relation to ventricular morphologies. Circulation 1988;77:62-9. 14. Moodie DS, Ritter DG, Tajik AJ, O'Fallon WM. Longterm follow-up in the unoperated univentricular heart. Am J CardioI1984;53:1124-8. 15. Moodie DS, Ritter DG, Tajik AJ, et a1. Long-term followup after palliative operation for univentricular heart. Am J Cardiol 1984;53:1648-51. 16. Seliern M, Muster AJ, Paul MH, Benson W. Relation between preoperative ventricular mass and outcome of the Fontan procedure in patients with tricuspid atresia. J Am ColI CardioI1989;14:750-5. 17. Humes RA, Feldt RH, Porter CJ, Julsrud PR, Puga FJ, Danielson GK. The modified Fontan operation for asplenia and polysplenia syndromes. J THORAC CARDIOVASC SURG 1988;96:212-8. 18. Fontan F, Kirklin JW, Fernandez G, et al. Outcome after a "perfect" Fontan operation. Circulation 1990;81:152036. 19. Kaye MP. Anatomic correction of transposition of great arteries. Mayo Clin Proc 1975;50:638-40. 20. Stansel H C. A new operation for d-loop transposition of the great vessels. Ann Thorac Surg 1975;19:565-7. 21. Damus PS. [Letter]. Ann Thorac Surg 1975;19:724-5. 22. Trusler GA, Freedom RM. Management of subaortic stenosis in the univentricular heart. Ann Thorac Surg 1989;47:643-4. 23. Waldmann JD, Lamberti JJ, George L, et al. Experience with Damus procedure. Circulation 1988;78(Pt 2):III32-9. 24. de Leval MR, Kilner P, Gewillig M, Bull C. Total cavopulmonary connection: a logical alternative to atriopulmonary connection for complex Fontan operations. J THORAC . CARDIOVASC SURG 1988;96:682-95. 25. Hopkins RA, Brenda EA, Serwer GA, Peterson RJ, Oldham HN. Physiological rationale for a bidirectional cavopulmonary shunt: a versatile complement to the Fontan principle. J THORAC CARDIOVASC SURG 1985;90:391-8. 26. Bridges ND, Jonas RA, Mayer JE, Flanagan MF, Keane JF, Castaneda AR. Bidirectional cavopulmonary anastomosis as interim palliation for high-risk Fontan candidates. Circulation 1990;82(Pt 2):IV 170-6.