Tetralogy of Fallot with a Single Pulmonary Artery: Operative Repair J. Jacques Mistrot, M.D., William F. Bernhard, M.D.,
Amnon Rosenthal, M.D., and Aldo R. Castaneda, M.D.
ABSTRACT Surgical repair was performed on 8 patients with tetralogy of Fallot and congenital or acquired absence of the left pulmonary artery. Prior palliative systemic-pulmonary artery shunts had been performed in the 5 patients with acquired absence of the pulmonary artery, and in none was repair of the damaged pulmonary artery possible. A valvecontaining conduit (Hancock) was used in each patient to prevent pulmonary valvular regurgitation during the early postoperative period. All patients survived operation and have exhibited marked symptomatic and hemodynamic improvement. This contrasts with the poor results of corrective operation previously reported in patients in this diagnostic category. We believe that the present improved results are due in large part to the valved conduit, and we thereforerecommendits use during repair in children or adults with tetralogy and a single pulmonary artery.
Despite low mortality and excellent long-term results after repair of tetralogy of Fallot (TOF), certain anatomical variations of this malformation continue to have a high operative mortality and morbidity. One such abnormality is the absence, either congenital (Dubuque syndrome) [12] or acquired, of one pulmonary artery. Since repair in patients with a single pulmonary artery has, in the past, resulted in a high mortality and morbidity [lll, several authors [4, 151 have advocated palliative operations rather than correction. The failure of repair has been attributed to pulmonary valvular regurgitation and increased pulmonary vascular resistance. This report deFrom the Departments of Cardiovascular Surgery and Cardiology, The Children’s Hospital Medical Center and Harvard Medical School, Boston, MA. Supported in part by US Public Health Service Grant no. POlHL10436, and by Pediatric Cardiology Grant no. OHL05855 from the National Institutes of Health. Accepted for publication Aug 9, 1976. Address reprint requests to Dr. Castaneda, Department of Cardiovascular Surgery, Children’s Hospital Medical Center, 300 Longwood Ave, Boston, MA 02115.
249
scribes the successful repair of TOF with a single pulmonary artery in 8 patients, using a valvecontaining conduit to avoid severe pulmonary regurgitation in the immediate postoperative period. Population and Operative Procedure From 1973 to 1975, 8 patients with TOF and absence or severe hypoplasia of one pulmonary artery have undergone repair at Children’s Hospital Medical Center, Boston. The age at operation ranged from 9 months to 32 years (Table 1). Three patients had congenital absence of the left pulmonary artery (Fig l),and in 5 the left pulmonary artery was atrophic or occluded because of a previous palliative shunt operation (Potts procedure in 3, end-to-end left Blalock-Taussig anastomosis in 1, and kinking of a left BlalockTaussig-pulmonary artery anastomosis in 1). Additional cardiovascular lesions included acquired pulmonary atresia in 2 patients, anomalous origin of the anterior descending coronary artery from the right coronary artery in 2 patients, and congenital absence of the pulmonary valve and aneurysmal dilatation of the right pulmonary artery in 1 patient (see Table 1). Preoperative cardiac catheterization data are shown in Table 2 (see below). The pulmonary artery pressure was normal in 6 patients and could not be measured in the 2 patients with pulmonary atresia. All patients underwent repair using conventional cardiopulmonary bypass techniques except for the youngest patient, aged 9 months (patient 1; see Table l), in whom deep hypothermic circulatory arrest was used. This patient required a Waterston shunt at 2 months of age. Repeat catheterization and angiography at 8 months of age, because of increasing cyanosis, revealed an absent left pulmonary artery and acquired pulmonary atresia. At the time of repair this patient weighed 6.7 kg, and a 12 mm conduit was employed.
250 The Annals of Thoracic Surgery Vol 23 No 3 March 1977
Table 1 . Clinical Data in 8 Patients with Tetralogy of Fallot and Absent Left Pulmonary Artery ~
Patient No.
Age at Operation (yr) 9 mo
Weight (kg) b.7
Type of Absent LPA
Additional Diagnoses
Congenital
Waterston; persistent LSVC Accessory RV chamber Absent PV Atresia PV; RBT; LBT LBT; RBT
10
29
Congenital
13
32 24
Congenital Acquired
10
19
67
Acquired
19
53
Acquired
29
45
Acquired
32
b7
Acquired
Potts; diabetes mellitus RBT; Potts; severe scoliosis Potts. AD from RCA
RV-PA Conduit Size (mm)
~~
Postoperative Complication
12
Residual VSD, CHF
20
Transient left phrenic Palsy
Follow-up (mo) 8
Excellent result after successful VSD closure
33
... ...
14 35
25
...
12
22
CHB, CHF
6
25
...
7
20
...
18
20 20
Comments
Patent LBT (end-to-end) a n d RBT, trivial VSD Permanent pacemaker; small residual shunt at Potts
LPA = left pulmonary artery; RV = right ventricle; VSD = ventricular septal defect; LBT = left Blalock-Taussig shunt; AD = anterior descending artery; PA = pulmonary artery; CHF = congestive heart failure; RBT = right Blalock-Taussig shunt; RCA = right coronary artery; PV = pulmonary valve; CHB = complete heart block; LSVC = left superior vena cava.
In all patients the ventricular septal defect (VSD) was closed with a Dacron patch, and a right ventricular-single pulmonary artery conduit was established with a Dacron conduit* containing a porcine valve anastomosed endto-side to the main pulmonary artery (Fig 2). Conduit sizes ranged from 12 to 25 mm in *Hancock Laboratories, Anaheim, CA.
Fig 1 . (Patient 2 . ) Preoperative angiogram demonstrating congenital absence of left pulmonary artery.
diameter (see Table 2). Reconstruction of the left pulmonary artery [21 was not possible in any of the 5 patients with acquired hypoplasia, atrophy, or occlusion. In 4 patients an 18-gauge polyethylene catheter was threaded through the right ventricular outflow tract across the conduit and into the distal right pulmonary artery to measure pulmonary artery pressure in the immediate postoperative period and also to record pull-back tracings during withdrawal of the catheter .
Results All 8 patients survived the procedure. Postoperative complications included permanent complete heart block, residual VSD, and transient phrenic nerve palsy in 1patient each (see Table 1). The patient with complete heart block developed congestive heart failure and has done well after placement of a permanent transvenous pacemaker. The patient with a residual VSD, the youngest of the group, required closure eight days after the original operation because of intractable congestive heart failure. He is now asymptomatic, and no significant gradient was measured across the 12-mm Hancock conduit one year postoperatively (Table 2). Hemodynamic data obtained in the immediate postoperative period or at subsequent cardiac catheterizations are shown in Table 2.
251 Mistrot et al: Tetralogy of Fallot with Single Pulmonary Artery
B
A
Fig2. (Patient 2.) Postoperative angiograms. ( A ) Anteroposterior v i e w demonstrates Hancock conduit connecting right ventricle to main pulmonary artery. ( B ) Lateral v i e w shows Hancock conduit connecting the right ventricle t o the main yulmonary artery (end-to-side anastomosis).
Table 2. Hemodynamic Data prior to and after Repair in 8 Patients with Tetralogy of Fallot and Absent Left Pulmonary Artery Preoperative Patient
Sao,
PAP
No.
(%)
( m m Hg)
1 2 3 4 5 6 7 8
68 88 88 76 88 84 75 YO
17/11 (12) 2018 (11) 1013 (6)
. . . (S)
20110 (16) 1215 (11)
. . . (3)
23/10
(a)
Interval from Operation to Postop Measurement
48 hr" 14 mo 24-48 hr" 1 Y' 1yr 1 Y' 24-48 hr" 14 m o
Postoperative Sao,
RVP
PAP
(%)
(mm Hg)
( m m Hg)
QdQS
R,K
95 94 95 95 96 80 95 93
4515 7414"
3815 . . . 30110 (14) 38/12 (22) 25110 (is) 2219 (13) 61/12 43/35 (39) 27/9
2.2 1.0 1.0 1.2 1.0 1.0 1.0 1.2
0.1 0.1 0.1 0.1 0.2 0.5 0.1
... 4215 5516 8315
... 79/11
(z)
(a)
...
aPostoperative measurements done through a polyethylene catheter inserted at operation. "In addition, patient had a tiny apical accessory right ventricular chamber with pressure of 170 mm Hg. Sao, = systemic oxygen saturation; PAP = pulmonary artery pressure; RVP = right ventricle pressure; Q,/Q, = pulmonary to systemic flow ratio; R,/R, = pulmonary to systemic resistance ratio.
252 The Annals of Thoracic Surgery Vol 23 No 3 March 1977
Mild pulmonary artery hypertension was present in 3 patients and moderate hypertension in 1. In the patients with mild hypertension, pressures were recorded within 48 hours postoperatively. In 2 of these patients we anticipate that the elevated pulmonary artery pressures will have decreased with time; in the third (Patient l),complete closure of the residual VSD lowered the pulmonary artery pressure to normal levels. In the patient with moderate hypertension (Patient 6) pulmonary vascular obstructive disease is present. Mild to moderate gradients (22 to 45 mm Hg) across the conduit were measured in 3 patients. The gradient was at the proximal anastomosis in Patient 8, at the xenograft valve in Patient 2, and at the distal anastomosis in Patient 6. Postoperative follow-up has ranged from 6 to 36 months (see Table 1). Only 1 patient (no. 6) remains on digitalis and diuretic therapy, and 2 additional patients are taking digitalis only. All patients are clinically well, asymptomatic, and fully active.
Comment In view of an operative mortality of 44 to 48%, several authors have held that a palliative systemic-pulmonary artery shunt using cardiopulmonary bypass is preferable to repair in patients with TOF and a single pulmonary artery [4,151. This high mortality has been ascribed to an increase in pulmonary vascular resistance secondary to thrombotic occlusion of the unilateral pulmonary vascular bed and also to pulmonary valvular regurgitation associated with the use of a right ventricular outflow gusset. The increased pulmonary vascular resistance aggravates the valvular insufficiency postoperatively [2, 3, 7-10, 121. When confronted with the first patient of this series, we speculated that the operative risk might be reduced by eliminating pulmonary valvular regurgitation, particularly during the early postoperative period. Use of a valved conduit rather than an outflow gusset seemed to accomplish this objective. Since all 8 patients survived operation and are doing well, we feel justified in recommending this operation for patients with TOF and congenital or acquired single pulmonary artery. The increased pulmonary vascular resistance
in some patients with TOF and a single pulmonary artery may be due to multiple pulmonary artery thromboses associated with prolonged hypoxemia, polycythemia, hyperviscosity, and diminished pulmonary flow. Similar observations have been made in other patients with TOF and small pulmonary arteries [5, 13, 141. One may also speculate that after normal pulmonary blood flow has been reestablished and the right-to-left shunt eliminated, with consequent decrease in blood viscosity, resolution of these thrombi with a fall in pulmonary vascular resistance may occur [ 6 ] . This course of events is suggested by early and late catheterization studies in a small number of patients with bilaterally patent pulmonary arteries [9]. The patient with TOF and a single pulmonary artery should have a favorable long-term prognosis after adequate repair, provided that the pulmonary vascular resistance is normal or will significantly decrease with time. The valved right ventricular outflow conduit should protect the right ventricle from volume overload while allowing time for the pulmonary resistance to return toward normal. There is little evidence to suggest that a shunt procedure will ”prepare” the pulmonary vascular bed any better than the reestablishment of right ventricular-pulmonary artery continuity. In fact, the volume load caused by a systemicpulmonary artery shunt in these patients may impose an additional burden on the left ventricle as well as a variety of other undesirable sequelae [lll. Recently, employing deep hypothermic circulatory arrest, we have used a right ventricular outflow gusset in repairing TOF and congenital absence of the left pulmonary artery in a 2-month-old infant. This patient tolerated the pulmonary valvular regurgitation extremely well and showed no evidence of right heart failure. The uncomplicated postoperative course in this infant may relate in part to Ferencz’s earlier findings of normal pulmonary vessels in neonates and infants with severe TOF [ 5 ] . If our experience with this infant is substantiated in larger groups of patients, it may be possible to avoid the use of valved conduits in the first months of life. With increasing age, changes within the pulmonary arteries may make correc-
253
Mistrot et al: Tetralogy of Fallot with Single Pulmonary Artery
tion of TOF with a single pulmonary artery more previous end-to-end anastomosis of systemic artery to pulmonary artery. J Thorac Cardiovasc hazardous. The poor results of repair of TOF Surg 49:635, 1965 with a single pulmonary artery when using 3. Bristow JD, Adrounny ZA, Porter GA, et al: standard techniques in children as young as 3 or Hernodynamic studies after total correction of te4 years of age support this viewpoint [l]. tralogy of Fallot. Am J Cardiol 9:924, 1962 Our initial enthusiasm for the use of valved 4. Donahoo JS, Brawley RK, Haller JA, et al: Correction of tetralogy of Fallot in patients with one conduits has recently been tempered by the pulmonary artery i n continuity with the right postoperative catheterization findings of reventricular outflow tract. Surgery 74:887, 1973 sidual gradients across them. * This complica5. Ferencz C: The pulmonary vascular bed in tetraltion was present in 3 of our patients. Gradients ogy of Fallot, part I. Bull Johns Hopkins Hosp across either the proximal or distal suture line 106:81, 1960 are mostly due to faulty operative technique and 6. Ferencz C: The pulmonary vascular bed in tetralogy of Fallot, part 11. Bull Johns Hopkins Hosp should thus be avoidable. Of greater concern are 106:100, 1960 gradients across the xenograft valve. Long-term 7. Gottsman MS, Beck W, Barnard CN, et al: Results follow-up will be required before the hemodyof repair of tetralogy of Fallot. Circulation 40:803, namic importance and overall fate of these 1969 valves can be fully assessed. 8. Kirklin JW, Karp RB: The Tetralogy of Fallot from a Surgical Viewpoint. Philadelphia, Saunders, In conclusion, the absence-either congenital 1970 or acquired (not reconstructible)-of a pulmonary artery in patients with TOF does not pre- 9. Kirklin JW, Wallace RB, McGoon DC, et al: Early and late results after intracardiac repair of tetralclude reparative operation. This can be done ogy of Fallot. Ann Surg 162:578, 1965 safely by employing a valve-containing conduit 10. Malm JR, Blumenthal S, Bowman FO Jr, et al: in the repair. The success of this procedure apFactors that modify hemodynamic results in total correction of tetralogy of Fallot. J Thorac Carpears related to two factors: (1) it maintains a diovasc Surg 52:502, 1966 competent pulmonary valve during the early 11. Morriss JH, McNamara DG: Residua, sequelae, postoperative course to protect the right ventriand complications of surgery for congenital heart cle from the combined stress of high pulmonary disease, Postoperative Congenital Heart Disease. vascular resistance and regurgitant pulmonary Edited by A Rosenthal, EH Sonnenblick, M Lesch. New York, Grune & Stratton, 1973, p 3 blood flow; and (2) it provides a gradual decrease in the pulmonary vascular resistance with 12. Nadas AS, Rosenbaum HD, Wittenberg MH, et al: Tetralogy of Fallot with unilateral pulmonary the passage of time. atresia. Circulation 8:328, 1953 13. Rich AR: A hitherto unrecognized tendency for References the development of widespread pulmonary vas1. Barratt-Boyes BG: Primary definitive intracardiac cular obstruction in patients with congenital operations in infants: tetralogy of Fallot, Adpulmonary atresia (tetralogy of Fallot). Bull Johns vances in Cardiovascular Surgery. Edited by JW Hopkins Hosp 82:389, 1948 Kirklin. New York, Grune & Stratton, 1973, p 155 14. Rosenthal A, Nathan DG, Marty AT, et al: Acute 2. Bjork VO: Surgical treatment for tetralogy of Fallot hemodynamic effects of red cell volume reduction with right pulmonary artery reconstruction after in polycythemia of cyanotic congenital heart disease. Circulation 47:297, 1970 15. Williams GD, Dungan WT, Campbell GS: Surgical treatment of tetralogy of Fallot with unilateral *Rocchini AP, Rosenthal A, Keane JF, et al: Hernodynamics absence of a pulmonary artery. Ann Thorac Surg after surgical repair with right ventricle to pulmonary artery conduit. (Submitted for publication.) 14:483, 1972
Amnon Rosenthal, M.D., and Aldo R. Castaneda, M.D.
ABSTRACT Surgical repair was performed on 8 patients with tetralogy of Fallot and congenital or acquired absence of the left pulmonary artery. Prior palliative systemic-pulmonary artery shunts had been performed in the 5 patients with acquired absence of the pulmonary artery, and in none was repair of the damaged pulmonary artery possible. A valvecontaining conduit (Hancock) was used in each patient to prevent pulmonary valvular regurgitation during the early postoperative period. All patients survived operation and have exhibited marked symptomatic and hemodynamic improvement. This contrasts with the poor results of corrective operation previously reported in patients in this diagnostic category. We believe that the present improved results are due in large part to the valved conduit, and we thereforerecommendits use during repair in children or adults with tetralogy and a single pulmonary artery.
Despite low mortality and excellent long-term results after repair of tetralogy of Fallot (TOF), certain anatomical variations of this malformation continue to have a high operative mortality and morbidity. One such abnormality is the absence, either congenital (Dubuque syndrome) [12] or acquired, of one pulmonary artery. Since repair in patients with a single pulmonary artery has, in the past, resulted in a high mortality and morbidity [lll, several authors [4, 151 have advocated palliative operations rather than correction. The failure of repair has been attributed to pulmonary valvular regurgitation and increased pulmonary vascular resistance. This report deFrom the Departments of Cardiovascular Surgery and Cardiology, The Children’s Hospital Medical Center and Harvard Medical School, Boston, MA. Supported in part by US Public Health Service Grant no. POlHL10436, and by Pediatric Cardiology Grant no. OHL05855 from the National Institutes of Health. Accepted for publication Aug 9, 1976. Address reprint requests to Dr. Castaneda, Department of Cardiovascular Surgery, Children’s Hospital Medical Center, 300 Longwood Ave, Boston, MA 02115.
249
scribes the successful repair of TOF with a single pulmonary artery in 8 patients, using a valvecontaining conduit to avoid severe pulmonary regurgitation in the immediate postoperative period. Population and Operative Procedure From 1973 to 1975, 8 patients with TOF and absence or severe hypoplasia of one pulmonary artery have undergone repair at Children’s Hospital Medical Center, Boston. The age at operation ranged from 9 months to 32 years (Table 1). Three patients had congenital absence of the left pulmonary artery (Fig l),and in 5 the left pulmonary artery was atrophic or occluded because of a previous palliative shunt operation (Potts procedure in 3, end-to-end left Blalock-Taussig anastomosis in 1, and kinking of a left BlalockTaussig-pulmonary artery anastomosis in 1). Additional cardiovascular lesions included acquired pulmonary atresia in 2 patients, anomalous origin of the anterior descending coronary artery from the right coronary artery in 2 patients, and congenital absence of the pulmonary valve and aneurysmal dilatation of the right pulmonary artery in 1 patient (see Table 1). Preoperative cardiac catheterization data are shown in Table 2 (see below). The pulmonary artery pressure was normal in 6 patients and could not be measured in the 2 patients with pulmonary atresia. All patients underwent repair using conventional cardiopulmonary bypass techniques except for the youngest patient, aged 9 months (patient 1; see Table l), in whom deep hypothermic circulatory arrest was used. This patient required a Waterston shunt at 2 months of age. Repeat catheterization and angiography at 8 months of age, because of increasing cyanosis, revealed an absent left pulmonary artery and acquired pulmonary atresia. At the time of repair this patient weighed 6.7 kg, and a 12 mm conduit was employed.
250 The Annals of Thoracic Surgery Vol 23 No 3 March 1977
Table 1 . Clinical Data in 8 Patients with Tetralogy of Fallot and Absent Left Pulmonary Artery ~
Patient No.
Age at Operation (yr) 9 mo
Weight (kg) b.7
Type of Absent LPA
Additional Diagnoses
Congenital
Waterston; persistent LSVC Accessory RV chamber Absent PV Atresia PV; RBT; LBT LBT; RBT
10
29
Congenital
13
32 24
Congenital Acquired
10
19
67
Acquired
19
53
Acquired
29
45
Acquired
32
b7
Acquired
Potts; diabetes mellitus RBT; Potts; severe scoliosis Potts. AD from RCA
RV-PA Conduit Size (mm)
~~
Postoperative Complication
12
Residual VSD, CHF
20
Transient left phrenic Palsy
Follow-up (mo) 8
Excellent result after successful VSD closure
33
... ...
14 35
25
...
12
22
CHB, CHF
6
25
...
7
20
...
18
20 20
Comments
Patent LBT (end-to-end) a n d RBT, trivial VSD Permanent pacemaker; small residual shunt at Potts
LPA = left pulmonary artery; RV = right ventricle; VSD = ventricular septal defect; LBT = left Blalock-Taussig shunt; AD = anterior descending artery; PA = pulmonary artery; CHF = congestive heart failure; RBT = right Blalock-Taussig shunt; RCA = right coronary artery; PV = pulmonary valve; CHB = complete heart block; LSVC = left superior vena cava.
In all patients the ventricular septal defect (VSD) was closed with a Dacron patch, and a right ventricular-single pulmonary artery conduit was established with a Dacron conduit* containing a porcine valve anastomosed endto-side to the main pulmonary artery (Fig 2). Conduit sizes ranged from 12 to 25 mm in *Hancock Laboratories, Anaheim, CA.
Fig 1 . (Patient 2 . ) Preoperative angiogram demonstrating congenital absence of left pulmonary artery.
diameter (see Table 2). Reconstruction of the left pulmonary artery [21 was not possible in any of the 5 patients with acquired hypoplasia, atrophy, or occlusion. In 4 patients an 18-gauge polyethylene catheter was threaded through the right ventricular outflow tract across the conduit and into the distal right pulmonary artery to measure pulmonary artery pressure in the immediate postoperative period and also to record pull-back tracings during withdrawal of the catheter .
Results All 8 patients survived the procedure. Postoperative complications included permanent complete heart block, residual VSD, and transient phrenic nerve palsy in 1patient each (see Table 1). The patient with complete heart block developed congestive heart failure and has done well after placement of a permanent transvenous pacemaker. The patient with a residual VSD, the youngest of the group, required closure eight days after the original operation because of intractable congestive heart failure. He is now asymptomatic, and no significant gradient was measured across the 12-mm Hancock conduit one year postoperatively (Table 2). Hemodynamic data obtained in the immediate postoperative period or at subsequent cardiac catheterizations are shown in Table 2.
251 Mistrot et al: Tetralogy of Fallot with Single Pulmonary Artery
B
A
Fig2. (Patient 2.) Postoperative angiograms. ( A ) Anteroposterior v i e w demonstrates Hancock conduit connecting right ventricle to main pulmonary artery. ( B ) Lateral v i e w shows Hancock conduit connecting the right ventricle t o the main yulmonary artery (end-to-side anastomosis).
Table 2. Hemodynamic Data prior to and after Repair in 8 Patients with Tetralogy of Fallot and Absent Left Pulmonary Artery Preoperative Patient
Sao,
PAP
No.
(%)
( m m Hg)
1 2 3 4 5 6 7 8
68 88 88 76 88 84 75 YO
17/11 (12) 2018 (11) 1013 (6)
. . . (S)
20110 (16) 1215 (11)
. . . (3)
23/10
(a)
Interval from Operation to Postop Measurement
48 hr" 14 mo 24-48 hr" 1 Y' 1yr 1 Y' 24-48 hr" 14 m o
Postoperative Sao,
RVP
PAP
(%)
(mm Hg)
( m m Hg)
QdQS
R,K
95 94 95 95 96 80 95 93
4515 7414"
3815 . . . 30110 (14) 38/12 (22) 25110 (is) 2219 (13) 61/12 43/35 (39) 27/9
2.2 1.0 1.0 1.2 1.0 1.0 1.0 1.2
0.1 0.1 0.1 0.1 0.2 0.5 0.1
... 4215 5516 8315
... 79/11
(z)
(a)
...
aPostoperative measurements done through a polyethylene catheter inserted at operation. "In addition, patient had a tiny apical accessory right ventricular chamber with pressure of 170 mm Hg. Sao, = systemic oxygen saturation; PAP = pulmonary artery pressure; RVP = right ventricle pressure; Q,/Q, = pulmonary to systemic flow ratio; R,/R, = pulmonary to systemic resistance ratio.
252 The Annals of Thoracic Surgery Vol 23 No 3 March 1977
Mild pulmonary artery hypertension was present in 3 patients and moderate hypertension in 1. In the patients with mild hypertension, pressures were recorded within 48 hours postoperatively. In 2 of these patients we anticipate that the elevated pulmonary artery pressures will have decreased with time; in the third (Patient l),complete closure of the residual VSD lowered the pulmonary artery pressure to normal levels. In the patient with moderate hypertension (Patient 6) pulmonary vascular obstructive disease is present. Mild to moderate gradients (22 to 45 mm Hg) across the conduit were measured in 3 patients. The gradient was at the proximal anastomosis in Patient 8, at the xenograft valve in Patient 2, and at the distal anastomosis in Patient 6. Postoperative follow-up has ranged from 6 to 36 months (see Table 1). Only 1 patient (no. 6) remains on digitalis and diuretic therapy, and 2 additional patients are taking digitalis only. All patients are clinically well, asymptomatic, and fully active.
Comment In view of an operative mortality of 44 to 48%, several authors have held that a palliative systemic-pulmonary artery shunt using cardiopulmonary bypass is preferable to repair in patients with TOF and a single pulmonary artery [4,151. This high mortality has been ascribed to an increase in pulmonary vascular resistance secondary to thrombotic occlusion of the unilateral pulmonary vascular bed and also to pulmonary valvular regurgitation associated with the use of a right ventricular outflow gusset. The increased pulmonary vascular resistance aggravates the valvular insufficiency postoperatively [2, 3, 7-10, 121. When confronted with the first patient of this series, we speculated that the operative risk might be reduced by eliminating pulmonary valvular regurgitation, particularly during the early postoperative period. Use of a valved conduit rather than an outflow gusset seemed to accomplish this objective. Since all 8 patients survived operation and are doing well, we feel justified in recommending this operation for patients with TOF and congenital or acquired single pulmonary artery. The increased pulmonary vascular resistance
in some patients with TOF and a single pulmonary artery may be due to multiple pulmonary artery thromboses associated with prolonged hypoxemia, polycythemia, hyperviscosity, and diminished pulmonary flow. Similar observations have been made in other patients with TOF and small pulmonary arteries [5, 13, 141. One may also speculate that after normal pulmonary blood flow has been reestablished and the right-to-left shunt eliminated, with consequent decrease in blood viscosity, resolution of these thrombi with a fall in pulmonary vascular resistance may occur [ 6 ] . This course of events is suggested by early and late catheterization studies in a small number of patients with bilaterally patent pulmonary arteries [9]. The patient with TOF and a single pulmonary artery should have a favorable long-term prognosis after adequate repair, provided that the pulmonary vascular resistance is normal or will significantly decrease with time. The valved right ventricular outflow conduit should protect the right ventricle from volume overload while allowing time for the pulmonary resistance to return toward normal. There is little evidence to suggest that a shunt procedure will ”prepare” the pulmonary vascular bed any better than the reestablishment of right ventricular-pulmonary artery continuity. In fact, the volume load caused by a systemicpulmonary artery shunt in these patients may impose an additional burden on the left ventricle as well as a variety of other undesirable sequelae [lll. Recently, employing deep hypothermic circulatory arrest, we have used a right ventricular outflow gusset in repairing TOF and congenital absence of the left pulmonary artery in a 2-month-old infant. This patient tolerated the pulmonary valvular regurgitation extremely well and showed no evidence of right heart failure. The uncomplicated postoperative course in this infant may relate in part to Ferencz’s earlier findings of normal pulmonary vessels in neonates and infants with severe TOF [ 5 ] . If our experience with this infant is substantiated in larger groups of patients, it may be possible to avoid the use of valved conduits in the first months of life. With increasing age, changes within the pulmonary arteries may make correc-
253
Mistrot et al: Tetralogy of Fallot with Single Pulmonary Artery
tion of TOF with a single pulmonary artery more previous end-to-end anastomosis of systemic artery to pulmonary artery. J Thorac Cardiovasc hazardous. The poor results of repair of TOF Surg 49:635, 1965 with a single pulmonary artery when using 3. Bristow JD, Adrounny ZA, Porter GA, et al: standard techniques in children as young as 3 or Hernodynamic studies after total correction of te4 years of age support this viewpoint [l]. tralogy of Fallot. Am J Cardiol 9:924, 1962 Our initial enthusiasm for the use of valved 4. Donahoo JS, Brawley RK, Haller JA, et al: Correction of tetralogy of Fallot in patients with one conduits has recently been tempered by the pulmonary artery i n continuity with the right postoperative catheterization findings of reventricular outflow tract. Surgery 74:887, 1973 sidual gradients across them. * This complica5. Ferencz C: The pulmonary vascular bed in tetraltion was present in 3 of our patients. Gradients ogy of Fallot, part I. Bull Johns Hopkins Hosp across either the proximal or distal suture line 106:81, 1960 are mostly due to faulty operative technique and 6. Ferencz C: The pulmonary vascular bed in tetralogy of Fallot, part 11. Bull Johns Hopkins Hosp should thus be avoidable. Of greater concern are 106:100, 1960 gradients across the xenograft valve. Long-term 7. Gottsman MS, Beck W, Barnard CN, et al: Results follow-up will be required before the hemodyof repair of tetralogy of Fallot. Circulation 40:803, namic importance and overall fate of these 1969 valves can be fully assessed. 8. Kirklin JW, Karp RB: The Tetralogy of Fallot from a Surgical Viewpoint. Philadelphia, Saunders, In conclusion, the absence-either congenital 1970 or acquired (not reconstructible)-of a pulmonary artery in patients with TOF does not pre- 9. Kirklin JW, Wallace RB, McGoon DC, et al: Early and late results after intracardiac repair of tetralclude reparative operation. This can be done ogy of Fallot. Ann Surg 162:578, 1965 safely by employing a valve-containing conduit 10. Malm JR, Blumenthal S, Bowman FO Jr, et al: in the repair. The success of this procedure apFactors that modify hemodynamic results in total correction of tetralogy of Fallot. J Thorac Carpears related to two factors: (1) it maintains a diovasc Surg 52:502, 1966 competent pulmonary valve during the early 11. Morriss JH, McNamara DG: Residua, sequelae, postoperative course to protect the right ventriand complications of surgery for congenital heart cle from the combined stress of high pulmonary disease, Postoperative Congenital Heart Disease. vascular resistance and regurgitant pulmonary Edited by A Rosenthal, EH Sonnenblick, M Lesch. New York, Grune & Stratton, 1973, p 3 blood flow; and (2) it provides a gradual decrease in the pulmonary vascular resistance with 12. Nadas AS, Rosenbaum HD, Wittenberg MH, et al: Tetralogy of Fallot with unilateral pulmonary the passage of time. atresia. Circulation 8:328, 1953 13. Rich AR: A hitherto unrecognized tendency for References the development of widespread pulmonary vas1. Barratt-Boyes BG: Primary definitive intracardiac cular obstruction in patients with congenital operations in infants: tetralogy of Fallot, Adpulmonary atresia (tetralogy of Fallot). Bull Johns vances in Cardiovascular Surgery. Edited by JW Hopkins Hosp 82:389, 1948 Kirklin. New York, Grune & Stratton, 1973, p 155 14. Rosenthal A, Nathan DG, Marty AT, et al: Acute 2. Bjork VO: Surgical treatment for tetralogy of Fallot hemodynamic effects of red cell volume reduction with right pulmonary artery reconstruction after in polycythemia of cyanotic congenital heart disease. Circulation 47:297, 1970 15. Williams GD, Dungan WT, Campbell GS: Surgical treatment of tetralogy of Fallot with unilateral *Rocchini AP, Rosenthal A, Keane JF, et al: Hernodynamics absence of a pulmonary artery. Ann Thorac Surg after surgical repair with right ventricle to pulmonary artery conduit. (Submitted for publication.) 14:483, 1972
