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Tetralogy of Fallot: Selective Surgical Management Can Minimize Operative Mortality
Tetralogy of Fallot: Selective Surgical Management Can Minimize Operative Mortality John W. Hammon, Jr., M.D., Clarke L. Henry, Jr., M.D., Walter H. Merrill, M.D., Thomas P. Graham, Jr., M.D., and Harvey W. Bender, Jr., M.D. ABSTRACT Although tetralogy of Fallot can be completely corrected at any age, it appears that preliminary shunting may be of benefit in infancy. To better define the optimum age for shunting, the following patient data were reviewed. One hundred five patients with tetralogy of Fallot were treated between December, 1975, and July, 1984. Eight of 100 patients undergoing intracardiac repair died. Operative mortality was 14.3% (4of 28 patients) when intracardiac repair was done before the patient was a year old, but only 5.6% (4of 72 patients) after that age. Seven (13%) of 54 patients requiring transannular patch reconstruction of the right ventricular outflow tract died, whereas only 1 (2.2%) of 46 having repair without this type of reconstruction died (p < 0.05). Twenty-one patients were initially palliated with systemic-pulmonary artery shunts, with 1 noncardiac death related to associated congenital neurological anomalies (4.8%). There was no statistically significant difference in mortality for primary versus secondary intracardiac repair. Left ventricular end-diastolic volume determination in 26 patients less than 2 years old demonstrated that 14 patients had small left ventricles and that 3 of them less than 1year of age died at corrective operation. The remaining 12 had a left ventricle of normal size, and 1 of them died at operation. Palliative shunts can be performed safely in the very young child with no increased mortality at subsequent intracardiac repair. Diffuse hypoplasia of the right ventricular outflow tract and pulmonary arteries requiring transannular patch reconstruction, and age less than 1 year both alter operative mortality, their combined impact being additive. Selective use of preliminary palliative shunts in patients less than 1 year old who have diminutive right ventricular outflow tracts or pulmonary arteries or both can reduce overall operative mortality.
decades. Nearly exclusive use of palliative systemicpulmonary artery anastomoses prior to later total correction was followed by broad application of primary intracardiac repair regardless of patient age and size [l,21. More recently, the selective use of primary intracardiac repair based on clinical and angiographic data has been promising, but criteria to determine optimal candidates for palliative versus complete repair in infants and young children have not been established [3-71. We reviewed our operative series of patients with tetralogy of Fallot in an attempt to establish criteria for patient subsets that would allow selective operative management. Such management would help minimize operative mortality and enhance functional recovery and postoperative clinical performance.
Material and Methods From December, 1975, through June, 1984, 105 patients with symptomatic tetralogy of Fallot were treated surgically at Vanderbilt University Hospital. There were 59 male and 46 female patients ranging in age from 2 days to 36 years. Seventy-two patients underwent total correction as the primary procedure, and 28 underwent intracardiac repair following a previous palliative systemic-pulmonary artery anastomosis. Twenty-one patients underwent 22 palliative shunts (20 BlalockTaussig, 1 Waterston, 1 prosthetic aorta-pulmonary artery shunt), and 16 have subsequently had secondary intracardiac repair. The patients were selected for either primary intracardiac repair or palliative shunt on the basis of age, size, and angiographic assessment of the nature and severity of the right ventricular outflow tract obstruction plus main and branch pulmonary artery size. Quantitative angiocardiography was performed to determine ventricular size and performance as well as pulmonary outflow tract anatomy using previously reported methods (81. Operative Techniques
The optimal management of patients with symptomatic tetralogy of Fallot has been debated over the last several From the Department of Cardiac and Thoracic Surgery, Section of Surgical Sciences, and Division of Pediatric Cardiology, Department of Pediatrics, Vanderbilt University Medical Center, Nashville, TN. Presented at the Twenty-first Annual Meeting of The Society of Thoracic Surgeons, Phoenix, AZ,Jan 21-23, 1985. Address reprint requests to Dr. Hammon, Department of Cardiac and Thoracic Surgery, Vanderbilt University Medical Center, 1211 21st Ave S, Suite 338, Nashville, TN 37212.
280
SHUNTS. These procedures were accomplished through a posterolateral thoracotomy in all instances. Optical magnification and the use of 6-0 or 7-0 monofilament suture material have facilitated placement of shunts in small infants. Our preference is the classic Blalock-Taussig shunt using the subclavian branch of the innominate artery. Although 1 Waterston anastomosis was used early in this series in a patient with unfavorable subclavian anatomy, a trend toward synthetic graft aortopulmonary anastomosis with 4 or 5 mm polytetrafluoroethylene grafts has recently been esSYSTEMIC-PULMONARY
281 Hammon et al: Operative Mortality in Tetralogy of Fallot
tablished in our institution as in other centers [9]. Nevertheless, only 1 such graft was included in this series. CORRECTIVE PROCEDURE. Complete repair in this series was carried out using two different perfusion techniques depending on the age and size of the patient. Profound hypothermia and circulatory arrest, similar to the technique of Barratt-Boyes and Neutze [l] and previously reported from this institution [lo], was the technique of choice in infants less than 1 year of age or 10 kg in body weight. In larger, older children, standard cardiopulmonary bypass techniques with systemic hypothermia to 25°C were utilized. Since 1980, hypothermic, hyperkalemic cardioplegia has been used in conjunction with topical hypothermia induced by the endocardia1 application of 4°C Ringer’s lactate solution during a single period of ischemic arrest while the majority of the intracardiac repair was carried out. Prior to this time, only topical myocardial hypothermia was used for myocardial protection. All repairs were carried out through a right ventriculotomy usually made in a longitudinal axis and parallel to the left anterior descending coronary artery. Hypertrophied right ventricular myocardium was carefully resected to provide unobstructed outflow from the right ventricle. The ventricular septa1 defect was closed with a double-velour Dacron patch in every instance. When transannular patch reconstruction was required, pericardium was used when possible and the incision was carried out to the pulmonary bifurcation and onto the left pulmonary artery when necessary because of bifurcation stenosis and results of cineangiography.
Data Analysis Charts for all patients undergoing operation for tetralogy of Fallot were reviewed and the data tabulated. Differences in data groups were assessed by Fischer’s exact test, and statistical significance was assumed when p was less than 0.05.
Results There were 9 deaths (8.6%) among the 105 patients operated on for symptomatic tetralogy of Fallot. One noncardiac death occurred after a Blalock-Taussig shunt from complications related to other complex congenital neurological anomalies. Eight of 100 patients undergoing total correction died in the postoperative period. Seven (13%)of the 54 patients who required the use of pericardial transannular patch reconstruction of the right ventricular outflow tract, died, as did 1 (2.2%)of the 46 patients who had repair without transannular patch reconstruction ( p < 0.05) (Fig 1). All deaths after total correction were related to low cardiac output. In 1 patient, low output was complicated by postoperative bleeding and tamponade. Of the 72 patients undergoing primary intracardiac repair, 38 required transannular patch reconstruction and 5 of them died (13.2%)(Fig 2). One (2.9%)of the remaining 34 patients undergoing repair without trans-
501
40 NUMBER OF PATIENTS 30
DEATHS
2ol 10
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Fig 1. Patients undergoing complete repair of tetralogy of Fallot with or without transannular patch (TAP) repair. The difference in mortality is statistically significant (p < 0.05).
50
t
DEATHS
NUMBER OF PATIENTS 3 0
20
._. . PRIMARY
REPAIR
SECONDARY REPAIR
Fig 2 . Comparison between patients having compirte repair as a prim a y or secondary (after a shunt) event. (TAP = transannular patch.)
annular patch reconstruction died. The overall operative mortality was 8.3% for primary total correction. Twenty-eight patients underwent secondary total correction (i.e., they had had previous palliation by systemic-pulmonary anastomosis). Two (12.5%) of 16 patients who required transannular patch reconstruction died. There were no deaths in the remaining 12 patients having repair without a transannular patch. Overall operative mortality for secondary total correction was 7.1%, which is not significantly different from that for primary repair (see Fig 2).
282 The Annals of Thoracic Surgery Vol 40 No 3 September 1985
X
o
DEATHS
-
DEATH SURVIVOR
160-
5 40 0[
I40
-
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OF PATIENTS
% NL LVEDV
2 S.D.
X 0
>I Y R
zo
Fig 3. Operative mortality in patients older or younger than 1year at repair of tetralogy of Fallot. (TAP = transannular patch.)
3
0
Twenty-one patients received 22 systemic-pulmonary artery anastomoses as initial palliative procedures; 20 of them were less than 1 year old at the time of operation. The single noncardiac postoperative death occurred as a result of associated complex congenital neurological anomalies. Twenty-eight infants less than 1 year of age underwent primary total correction with 4 deaths (14.3%). This is in contrast to the 4 deaths (5.6%) among 72 patients having repair after they were l year old (Fig 3). Three (15.8%) of 19 infants (0 to 12 months old) who underwent transannular patch reconstruction died, whereas 1 (11.1%)of 9 infants undergoing repair without a transannular patch failed to survive. In the 72 patients who had repair after the age of l year, all 4 deaths (11.4%)occurred among the 35 patients requiring transannular patch reconstruction. There were no deaths among the 37 patients who underwent repair without a transannular patch. Twenty-six children less than 2 years of age who underwent primary intracardiac repair had biplane ventriculography and determination of left ventricular enddiastolic volume (LVEDV) preoperatively (Fig 4). Eleven had an LVEDV of less than 2 standard deviations from the normal, and 2 of them died. Only 1 of 15 with a normal or enlarged LVEDV died. This was not statistically significant, although it should be noted that almost half of the infants studied had small left ventricles. The ratio of the diameter of the aorta and the right pulmonary artery was calculated in 31 patients (Fig 5). The ratio averaged 0.48, and in none was it less than 0.3 (considered by Tucker and colleagues [5] too small for primary repair). Deaths were randomly scattered in this analysis, and there was no significant association with smaller pulmonary arteries. The frequency of the requirement for transannular patch reconstruction (54% overall) was not significantly different whether the total correction was primary (52.8%)or secondary (57.1%),but the incidence of trans-
;
:
9
6
12
15
18
21
24
AGE ( M O N T H S )
Fig 4. Left ventricular end-diastolic volume (LVEDV) in 26 patients less than 2 years old undergoing repair of tetralogy of Fallot. (W NL = percent normal; SD = standard deviation.)
X o
Ao
- DEATH - SURVIVOR
.6
: .I0
3
6
9
12
15
18
21
24
AGE (MONTHS)
Fig 5. The ratio of the diameter of the right pulmonary artery (RPA) to that of the ascending aorta (Ao) in 31 children undergoing correction of tetralogy of Fallot.
annular patch reconstruction was 68% in infants 0 to 12 months old and only 49% in patients older than 1 year. There was no significant difference in operative mortality following primary (8.3%) or secondary (7.1%) intracardiac repair regardless of age or the use of transannular patch reconstruction. Matched for age, there was no prognostic impact of patient weight on operative mortality.
Comment Numerous techniques have been described to identify the patient subpopulation put at greatest risk by primary total correction of tetralogy of Fallot who might best be
283 Hammon et a 1 Operative Mortality in Tetralogy of Fallot
served by an initial palliative procedure with total correction at a later time. Though young age and small size are the characteristics often described as important, it appears that associated physiological and morphological factors play a greater role. Tucker and associates [5] noted the importance of the ratio of the diameter of the right pulmonary artery to the diameter of the aorta, and found that a ratio of 0.3 was the lower limit of acceptable pulmonary artery size to safely accommodate full cardiac output after total correction. Although some reports [2, 41 have shown no increase in operative mortality in patients requiring transannular patch reconstruction, Kirklin and co-workers [ll, 121 demonstrated that the two-stage approach is safer than primary repair in only the very small, young infant (less than 0.35 m2 of body surface area, less than 6 months old), except when no transannular patch reconstruction is required in the primary repair. However, they stated that primary repair is as safe as the two-stage approach in larger, older infants (more than 0.48 m2, more than 8 months old), even if primary repair requires a transannular patch. Castaneda and co-workers (21 preferred to completely repair all children at presentation and despite age, size, or other criteria; their reported operative mortality was 7.6% for patients 6 months old or less. Although complete studies are lacking, it seems that the smaller infant with tetralogy of Fallot is likely to have a smaller left ventricle [12]. A 1984 report by Nomoto and colleagues [13]indicated a greater need for inotropic agents in children undergoing primary repair who are less than 2 years old and have small left ventricles. Another criterion in this group of patients is severe low cardiac output in those with an LVEDV of less than 70% of normal. In our study, 14 of 26 patients less than 2 years of age who had left ventricular volume determinations proved to have small left ventricles, and 3 of them died. Three of the 4 patients who died in this group of 26 were less than 1 year of age. This indicates the large number of patients less than 2 years old with small left ventricles, and suggests a higher relative risk of death in children less than 1 year old with a small left ventricle. The precise reason for this is unclear but may relate to the higher risk of cardiopulmonary bypass in the infant [12]. The requirement for transannular patch reconstruction of the right ventricular outflow tract during intracardiac repair had a significant impact on operative mortality (13% with, 2.2% without; p < 0.05). The operative mortality of intracardiac repair in infants (14.3%)is more than double that for patients older than 1 year (5.6%), though this did not reach statistical significance. The impact of young age and the requirement for transannular patch reconstruction on operative mortality are independent and additive. The highest operative mortality was in infants undergoing repair with transannular patch reconstruction (15.8%).This contrasts significantly with the zero operative mortality for patients having repair after 1 year of age without the requirement for transannular patch reconstruction (p < 0.05). It is un-
proven, however, that a preliminary shunt in these patients would obviate the need for a transannular patch later. The proponents of primary repair for all patients cite late morbidity of systemic-pulmonary artery shunts as a disadvantage of the two-stage approach [2]. This has been a problem more common to the Waterston aortapulmonary artery anastomosis than to the Blalock. Taussig subclavian-pulmonary artery anastomosis [6]. In our series, all patients who received a palliative shunt and are alive have either undergone total correction or are awaiting correction. There has been no late morbidity or mortality in these patients. To support a two-stage approach, the initial palliative procedure must be performed with little or no operative mortality, consistent palliation, and no late morbidity. Similarqy, the risk of operation at secondary total correction must not exceed that of primary repair due to the presence of a previously placed shunt. Our data support primary intracardiac repair in the majority of patients with symptomatic tetralogy of Fallot. However, in the symptomatic infant less than l year of age with severe diffuse hypoplasia of the right ventricular outflow tract that would require transannular patch reconstruction, a preliminary palliative BlalockTaussig anastomosis is preferred. With rare exceptions, the remainder can undergo primary repair with low morbidity and mortality, especially if a transannular patch is avoided.
The authors thank Judy Burger for her assistance with left ventricular volume analysis and Pat de la Guardia for typing the manuscript.
References 1. Barratt-Boyes BG, Neutze JM: Previous repair of tetralogy of Fallot in infancy using profound hypothermia with circulatory arrest and limited cardiopulmonary bypass: a
comparison with conventional two-stage management. Ann Surg 178:406, 1973 2. Castaneda AR, Freed MD, Williams RG, et al: Repair of tetralogy of Fallot in infancy: early and late results. J Thorac Cardiovasc Surg 74:372, 1977 3. Bender HW, Fisher RD, Conkle DM, et al: Selective operative treatment for tetralogy of Fallot: rationale and results. Ann Surg 183:685,1976 4. Sdnchez HE, Cornish EM, Feng CS, et al: The surgical treatment of tetralogy of Fallot. Ann Thorac Surg 37431, 1984 5. Tucker WY, Turley K, Ullyot DJ, et al: Management of symptomatic tetralogy of Fallot in the first year of life. J Thorac Cardiovasc Surg 78:494, 1979 6 . Arciniegas E, Farooki ZQ, Hakimi M, et al: Results of twostage treatment of tetralogy of Fallot. J Thorac Cardiovasc Surg 799376, 1980 7. Arciniegas E, Farooki ZQ, Hakimi M, et al: Early and late results of total correction of tetralogy of Fallot. J Thorac Cardiovasc Surg 80:770, 1980 8. Graham TI', CordelI GD, Bender HW: Ventricular function following surgery in the child with congenital heart disease
284 The Annals of Thoracic Surgery Vol 40 No 3 September 1985
9.
10.
11.
12.
13.
after surgery. In Kidd BSL, Rowe RD (eds): Mt. Kisco, NY, Futura, 1976 de Leva1 MR, McKay R, Jones M, et al: Modified BlalockTaussig shunt: use of subclavian orifice as flow regulator in prosthetic systemic-pulmonary shunts. J Thorac Cardiovasc Surg 81:112, 1981 Bender HW, Fisher RD, Walker WE, et al: Reparative cardiac surgery in infants and small children: five years’ experience with profound hypothermia and circulatory arrest. Ann Surg 190:437, 1979 Kirklin JW, Blackstone EW, Pacific0 AD, et al: Routine primary repair vs. two-stage repair of tetralogy of Fallot. Circulation 60:373, 1979 Kirklin JW, Blackstone EW, Kirklin JK, et al: Surgical results and protocols in the spectrum of tetralogy of Fallot. Ann Surg 198:251, 1983 Nomoto S, Murakoa R, Yokota M, et al: Left ventricular volume as a predictor of postoperative hemodynamics and a criterion for total correction of tetralogy of Fallot. J Thorac Cardiovasc Surg 88:389, 1984
Discussion (Boston, MA): I congratulate Dr. Hammon and his colleagues on this interesting presentation. Although my associates and I prefer primary repair of tetralogy of Fallot irrespective of age or weight, 1 feel no evangelical zest to proselytize in favor of a one-stage repair rather than the twostage conventional approach as proposed again by Dr. Hammon. However, I fail to understand the logic of their argument that a preliminary palliative operation in patients less than 1 year old reduces overall mortality. Also, the incidence of transannular patches in the primary repair group and in the twostage repair group was about the same, namely, slightly greater than SO%, as was the overall operative mortality of about 13 to 15% in both groups. Thus, no evidence is presented that a preliminary shunt reduces the need of a transannular patch or that it reduced combined operative mortality. Although operative mortality statistics are important, it behooves us to objectively measure late functional results. I would be particularly interested to learn about postoperative right ventricular pressures in patients with or without transannular patches. In our experience at Children’s Hospital Medical Center, the incidence of transannular patches in the group less than 6 months of age is approximately 80%; after 6 months, it is close to that presented here. For 160 babies repaired within the first year of life, overall mortality is 6%. In our experience, neither age nor the need for a transannular patch affects operative mortality. Left ventricular end-diastolic volume did not seem to affect outcome in our series. Two of our patients who died had absent pulmonary valve syndrome, 1 had idiopathic hypertrophic subaortic stenosis, and another had a preoperative myocardial infarction. Thus, a DR. ALDO R. CASTANEDA
number of extraneous factors added to the overall operative mortality. Finally, postoperative measurements in 65 of these patients showed that more than 80% had no or only minimal residual gradients. Four patients with gradients higher than 60 mm Hg across the right ventricular outflow tract had pulmonary atresia. We now advocate the use of conduits in this group of patients. DR. FREDERICK A. CRAWFORD, J R . : (Charleston, sc):I enjoyed this presentation very much and agree with its conclusions. Since 1978, I have operated on 50 consecutive patients with tetralogy of Fallot, 6 of whom have died. Mortality was significantly higher in those children less than 1 year of age. All 6 deaths occurred in the 31 patients who required transannular patching. There were no deaths in 19 patients who did not require transannular patching, a significant difference. It is clear that infants less than 1 year of age can undergo successful correction of tetralogy of Fallot, but the risk is increased, especially in those who require transannular patching. After analysis of the data hom the University of Alabama and early data from this series, I adopted a policy in 1980 of palliative shunting for infants less than 1 year of age who were predicted to require a transannular patch. There have been no operative deaths in this series since that time. I have two questions for the authors. First, our pediatric cardiologists frequently use propranolol as palliation, and in some infants the need for a palliative shunt can be avoided. Has this been useful for you? Second, in those patients in whom shunts are placed, is the time of total correction based on symptoms or age?
My colleagues and I appreciate the comments of the discussants. To Dr. Castaneda, our appreciation for his remarks, especially for pointing out that a preliminary shunt probably does not influence whether or not a transannular patch will be needed in the later repair. Our operative mortality in patients less than 1 year old was almost double that of patients older than l year. This may have been influenced more by the deleterious effect of cardiopulmonary bypass and other nonspecific factors than by the use of a transannular patch, although transannular patch reconstruction undoubtedly exposes the heart to greater stress than does closing the right ventricle primarily. We do not measure right ventricular pressures in our patients and cannot comment on that particular question. We appreciate Dr. Crawford‘s experience, which mirrors our own. Our cardiologists have begun to use propranolol in the younger patients to prevent symptoms until an older age, although the number of patients in our series is too small to permit a comparison. In most instances if a patient receives a shunt before the age of 6 months, minor symptomatology such as mild cyanosis will appear when he or she is 2 to 5 years old, and correction is performed at that time. DR. HAMMON:
decades. Nearly exclusive use of palliative systemicpulmonary artery anastomoses prior to later total correction was followed by broad application of primary intracardiac repair regardless of patient age and size [l,21. More recently, the selective use of primary intracardiac repair based on clinical and angiographic data has been promising, but criteria to determine optimal candidates for palliative versus complete repair in infants and young children have not been established [3-71. We reviewed our operative series of patients with tetralogy of Fallot in an attempt to establish criteria for patient subsets that would allow selective operative management. Such management would help minimize operative mortality and enhance functional recovery and postoperative clinical performance.
Material and Methods From December, 1975, through June, 1984, 105 patients with symptomatic tetralogy of Fallot were treated surgically at Vanderbilt University Hospital. There were 59 male and 46 female patients ranging in age from 2 days to 36 years. Seventy-two patients underwent total correction as the primary procedure, and 28 underwent intracardiac repair following a previous palliative systemic-pulmonary artery anastomosis. Twenty-one patients underwent 22 palliative shunts (20 BlalockTaussig, 1 Waterston, 1 prosthetic aorta-pulmonary artery shunt), and 16 have subsequently had secondary intracardiac repair. The patients were selected for either primary intracardiac repair or palliative shunt on the basis of age, size, and angiographic assessment of the nature and severity of the right ventricular outflow tract obstruction plus main and branch pulmonary artery size. Quantitative angiocardiography was performed to determine ventricular size and performance as well as pulmonary outflow tract anatomy using previously reported methods (81. Operative Techniques
The optimal management of patients with symptomatic tetralogy of Fallot has been debated over the last several From the Department of Cardiac and Thoracic Surgery, Section of Surgical Sciences, and Division of Pediatric Cardiology, Department of Pediatrics, Vanderbilt University Medical Center, Nashville, TN. Presented at the Twenty-first Annual Meeting of The Society of Thoracic Surgeons, Phoenix, AZ,Jan 21-23, 1985. Address reprint requests to Dr. Hammon, Department of Cardiac and Thoracic Surgery, Vanderbilt University Medical Center, 1211 21st Ave S, Suite 338, Nashville, TN 37212.
280
SHUNTS. These procedures were accomplished through a posterolateral thoracotomy in all instances. Optical magnification and the use of 6-0 or 7-0 monofilament suture material have facilitated placement of shunts in small infants. Our preference is the classic Blalock-Taussig shunt using the subclavian branch of the innominate artery. Although 1 Waterston anastomosis was used early in this series in a patient with unfavorable subclavian anatomy, a trend toward synthetic graft aortopulmonary anastomosis with 4 or 5 mm polytetrafluoroethylene grafts has recently been esSYSTEMIC-PULMONARY
281 Hammon et al: Operative Mortality in Tetralogy of Fallot
tablished in our institution as in other centers [9]. Nevertheless, only 1 such graft was included in this series. CORRECTIVE PROCEDURE. Complete repair in this series was carried out using two different perfusion techniques depending on the age and size of the patient. Profound hypothermia and circulatory arrest, similar to the technique of Barratt-Boyes and Neutze [l] and previously reported from this institution [lo], was the technique of choice in infants less than 1 year of age or 10 kg in body weight. In larger, older children, standard cardiopulmonary bypass techniques with systemic hypothermia to 25°C were utilized. Since 1980, hypothermic, hyperkalemic cardioplegia has been used in conjunction with topical hypothermia induced by the endocardia1 application of 4°C Ringer’s lactate solution during a single period of ischemic arrest while the majority of the intracardiac repair was carried out. Prior to this time, only topical myocardial hypothermia was used for myocardial protection. All repairs were carried out through a right ventriculotomy usually made in a longitudinal axis and parallel to the left anterior descending coronary artery. Hypertrophied right ventricular myocardium was carefully resected to provide unobstructed outflow from the right ventricle. The ventricular septa1 defect was closed with a double-velour Dacron patch in every instance. When transannular patch reconstruction was required, pericardium was used when possible and the incision was carried out to the pulmonary bifurcation and onto the left pulmonary artery when necessary because of bifurcation stenosis and results of cineangiography.
Data Analysis Charts for all patients undergoing operation for tetralogy of Fallot were reviewed and the data tabulated. Differences in data groups were assessed by Fischer’s exact test, and statistical significance was assumed when p was less than 0.05.
Results There were 9 deaths (8.6%) among the 105 patients operated on for symptomatic tetralogy of Fallot. One noncardiac death occurred after a Blalock-Taussig shunt from complications related to other complex congenital neurological anomalies. Eight of 100 patients undergoing total correction died in the postoperative period. Seven (13%)of the 54 patients who required the use of pericardial transannular patch reconstruction of the right ventricular outflow tract, died, as did 1 (2.2%)of the 46 patients who had repair without transannular patch reconstruction ( p < 0.05) (Fig 1). All deaths after total correction were related to low cardiac output. In 1 patient, low output was complicated by postoperative bleeding and tamponade. Of the 72 patients undergoing primary intracardiac repair, 38 required transannular patch reconstruction and 5 of them died (13.2%)(Fig 2). One (2.9%)of the remaining 34 patients undergoing repair without trans-
501
40 NUMBER OF PATIENTS 30
DEATHS
2ol 10
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TAP
NO TAP
Fig 1. Patients undergoing complete repair of tetralogy of Fallot with or without transannular patch (TAP) repair. The difference in mortality is statistically significant (p < 0.05).
50
t
DEATHS
NUMBER OF PATIENTS 3 0
20
._. . PRIMARY
REPAIR
SECONDARY REPAIR
Fig 2 . Comparison between patients having compirte repair as a prim a y or secondary (after a shunt) event. (TAP = transannular patch.)
annular patch reconstruction died. The overall operative mortality was 8.3% for primary total correction. Twenty-eight patients underwent secondary total correction (i.e., they had had previous palliation by systemic-pulmonary anastomosis). Two (12.5%) of 16 patients who required transannular patch reconstruction died. There were no deaths in the remaining 12 patients having repair without a transannular patch. Overall operative mortality for secondary total correction was 7.1%, which is not significantly different from that for primary repair (see Fig 2).
282 The Annals of Thoracic Surgery Vol 40 No 3 September 1985
X
o
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-
DEATH SURVIVOR
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5 40 0[
I40
-
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% NL LVEDV
2 S.D.
X 0
>I Y R
zo
Fig 3. Operative mortality in patients older or younger than 1year at repair of tetralogy of Fallot. (TAP = transannular patch.)
3
0
Twenty-one patients received 22 systemic-pulmonary artery anastomoses as initial palliative procedures; 20 of them were less than 1 year old at the time of operation. The single noncardiac postoperative death occurred as a result of associated complex congenital neurological anomalies. Twenty-eight infants less than 1 year of age underwent primary total correction with 4 deaths (14.3%). This is in contrast to the 4 deaths (5.6%) among 72 patients having repair after they were l year old (Fig 3). Three (15.8%) of 19 infants (0 to 12 months old) who underwent transannular patch reconstruction died, whereas 1 (11.1%)of 9 infants undergoing repair without a transannular patch failed to survive. In the 72 patients who had repair after the age of l year, all 4 deaths (11.4%)occurred among the 35 patients requiring transannular patch reconstruction. There were no deaths among the 37 patients who underwent repair without a transannular patch. Twenty-six children less than 2 years of age who underwent primary intracardiac repair had biplane ventriculography and determination of left ventricular enddiastolic volume (LVEDV) preoperatively (Fig 4). Eleven had an LVEDV of less than 2 standard deviations from the normal, and 2 of them died. Only 1 of 15 with a normal or enlarged LVEDV died. This was not statistically significant, although it should be noted that almost half of the infants studied had small left ventricles. The ratio of the diameter of the aorta and the right pulmonary artery was calculated in 31 patients (Fig 5). The ratio averaged 0.48, and in none was it less than 0.3 (considered by Tucker and colleagues [5] too small for primary repair). Deaths were randomly scattered in this analysis, and there was no significant association with smaller pulmonary arteries. The frequency of the requirement for transannular patch reconstruction (54% overall) was not significantly different whether the total correction was primary (52.8%)or secondary (57.1%),but the incidence of trans-
;
:
9
6
12
15
18
21
24
AGE ( M O N T H S )
Fig 4. Left ventricular end-diastolic volume (LVEDV) in 26 patients less than 2 years old undergoing repair of tetralogy of Fallot. (W NL = percent normal; SD = standard deviation.)
X o
Ao
- DEATH - SURVIVOR
.6
: .I0
3
6
9
12
15
18
21
24
AGE (MONTHS)
Fig 5. The ratio of the diameter of the right pulmonary artery (RPA) to that of the ascending aorta (Ao) in 31 children undergoing correction of tetralogy of Fallot.
annular patch reconstruction was 68% in infants 0 to 12 months old and only 49% in patients older than 1 year. There was no significant difference in operative mortality following primary (8.3%) or secondary (7.1%) intracardiac repair regardless of age or the use of transannular patch reconstruction. Matched for age, there was no prognostic impact of patient weight on operative mortality.
Comment Numerous techniques have been described to identify the patient subpopulation put at greatest risk by primary total correction of tetralogy of Fallot who might best be
283 Hammon et a 1 Operative Mortality in Tetralogy of Fallot
served by an initial palliative procedure with total correction at a later time. Though young age and small size are the characteristics often described as important, it appears that associated physiological and morphological factors play a greater role. Tucker and associates [5] noted the importance of the ratio of the diameter of the right pulmonary artery to the diameter of the aorta, and found that a ratio of 0.3 was the lower limit of acceptable pulmonary artery size to safely accommodate full cardiac output after total correction. Although some reports [2, 41 have shown no increase in operative mortality in patients requiring transannular patch reconstruction, Kirklin and co-workers [ll, 121 demonstrated that the two-stage approach is safer than primary repair in only the very small, young infant (less than 0.35 m2 of body surface area, less than 6 months old), except when no transannular patch reconstruction is required in the primary repair. However, they stated that primary repair is as safe as the two-stage approach in larger, older infants (more than 0.48 m2, more than 8 months old), even if primary repair requires a transannular patch. Castaneda and co-workers (21 preferred to completely repair all children at presentation and despite age, size, or other criteria; their reported operative mortality was 7.6% for patients 6 months old or less. Although complete studies are lacking, it seems that the smaller infant with tetralogy of Fallot is likely to have a smaller left ventricle [12]. A 1984 report by Nomoto and colleagues [13]indicated a greater need for inotropic agents in children undergoing primary repair who are less than 2 years old and have small left ventricles. Another criterion in this group of patients is severe low cardiac output in those with an LVEDV of less than 70% of normal. In our study, 14 of 26 patients less than 2 years of age who had left ventricular volume determinations proved to have small left ventricles, and 3 of them died. Three of the 4 patients who died in this group of 26 were less than 1 year of age. This indicates the large number of patients less than 2 years old with small left ventricles, and suggests a higher relative risk of death in children less than 1 year old with a small left ventricle. The precise reason for this is unclear but may relate to the higher risk of cardiopulmonary bypass in the infant [12]. The requirement for transannular patch reconstruction of the right ventricular outflow tract during intracardiac repair had a significant impact on operative mortality (13% with, 2.2% without; p < 0.05). The operative mortality of intracardiac repair in infants (14.3%)is more than double that for patients older than 1 year (5.6%), though this did not reach statistical significance. The impact of young age and the requirement for transannular patch reconstruction on operative mortality are independent and additive. The highest operative mortality was in infants undergoing repair with transannular patch reconstruction (15.8%).This contrasts significantly with the zero operative mortality for patients having repair after 1 year of age without the requirement for transannular patch reconstruction (p < 0.05). It is un-
proven, however, that a preliminary shunt in these patients would obviate the need for a transannular patch later. The proponents of primary repair for all patients cite late morbidity of systemic-pulmonary artery shunts as a disadvantage of the two-stage approach [2]. This has been a problem more common to the Waterston aortapulmonary artery anastomosis than to the Blalock. Taussig subclavian-pulmonary artery anastomosis [6]. In our series, all patients who received a palliative shunt and are alive have either undergone total correction or are awaiting correction. There has been no late morbidity or mortality in these patients. To support a two-stage approach, the initial palliative procedure must be performed with little or no operative mortality, consistent palliation, and no late morbidity. Similarqy, the risk of operation at secondary total correction must not exceed that of primary repair due to the presence of a previously placed shunt. Our data support primary intracardiac repair in the majority of patients with symptomatic tetralogy of Fallot. However, in the symptomatic infant less than l year of age with severe diffuse hypoplasia of the right ventricular outflow tract that would require transannular patch reconstruction, a preliminary palliative BlalockTaussig anastomosis is preferred. With rare exceptions, the remainder can undergo primary repair with low morbidity and mortality, especially if a transannular patch is avoided.
The authors thank Judy Burger for her assistance with left ventricular volume analysis and Pat de la Guardia for typing the manuscript.
References 1. Barratt-Boyes BG, Neutze JM: Previous repair of tetralogy of Fallot in infancy using profound hypothermia with circulatory arrest and limited cardiopulmonary bypass: a
comparison with conventional two-stage management. Ann Surg 178:406, 1973 2. Castaneda AR, Freed MD, Williams RG, et al: Repair of tetralogy of Fallot in infancy: early and late results. J Thorac Cardiovasc Surg 74:372, 1977 3. Bender HW, Fisher RD, Conkle DM, et al: Selective operative treatment for tetralogy of Fallot: rationale and results. Ann Surg 183:685,1976 4. Sdnchez HE, Cornish EM, Feng CS, et al: The surgical treatment of tetralogy of Fallot. Ann Thorac Surg 37431, 1984 5. Tucker WY, Turley K, Ullyot DJ, et al: Management of symptomatic tetralogy of Fallot in the first year of life. J Thorac Cardiovasc Surg 78:494, 1979 6 . Arciniegas E, Farooki ZQ, Hakimi M, et al: Results of twostage treatment of tetralogy of Fallot. J Thorac Cardiovasc Surg 799376, 1980 7. Arciniegas E, Farooki ZQ, Hakimi M, et al: Early and late results of total correction of tetralogy of Fallot. J Thorac Cardiovasc Surg 80:770, 1980 8. Graham TI', CordelI GD, Bender HW: Ventricular function following surgery in the child with congenital heart disease
284 The Annals of Thoracic Surgery Vol 40 No 3 September 1985
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after surgery. In Kidd BSL, Rowe RD (eds): Mt. Kisco, NY, Futura, 1976 de Leva1 MR, McKay R, Jones M, et al: Modified BlalockTaussig shunt: use of subclavian orifice as flow regulator in prosthetic systemic-pulmonary shunts. J Thorac Cardiovasc Surg 81:112, 1981 Bender HW, Fisher RD, Walker WE, et al: Reparative cardiac surgery in infants and small children: five years’ experience with profound hypothermia and circulatory arrest. Ann Surg 190:437, 1979 Kirklin JW, Blackstone EW, Pacific0 AD, et al: Routine primary repair vs. two-stage repair of tetralogy of Fallot. Circulation 60:373, 1979 Kirklin JW, Blackstone EW, Kirklin JK, et al: Surgical results and protocols in the spectrum of tetralogy of Fallot. Ann Surg 198:251, 1983 Nomoto S, Murakoa R, Yokota M, et al: Left ventricular volume as a predictor of postoperative hemodynamics and a criterion for total correction of tetralogy of Fallot. J Thorac Cardiovasc Surg 88:389, 1984
Discussion (Boston, MA): I congratulate Dr. Hammon and his colleagues on this interesting presentation. Although my associates and I prefer primary repair of tetralogy of Fallot irrespective of age or weight, 1 feel no evangelical zest to proselytize in favor of a one-stage repair rather than the twostage conventional approach as proposed again by Dr. Hammon. However, I fail to understand the logic of their argument that a preliminary palliative operation in patients less than 1 year old reduces overall mortality. Also, the incidence of transannular patches in the primary repair group and in the twostage repair group was about the same, namely, slightly greater than SO%, as was the overall operative mortality of about 13 to 15% in both groups. Thus, no evidence is presented that a preliminary shunt reduces the need of a transannular patch or that it reduced combined operative mortality. Although operative mortality statistics are important, it behooves us to objectively measure late functional results. I would be particularly interested to learn about postoperative right ventricular pressures in patients with or without transannular patches. In our experience at Children’s Hospital Medical Center, the incidence of transannular patches in the group less than 6 months of age is approximately 80%; after 6 months, it is close to that presented here. For 160 babies repaired within the first year of life, overall mortality is 6%. In our experience, neither age nor the need for a transannular patch affects operative mortality. Left ventricular end-diastolic volume did not seem to affect outcome in our series. Two of our patients who died had absent pulmonary valve syndrome, 1 had idiopathic hypertrophic subaortic stenosis, and another had a preoperative myocardial infarction. Thus, a DR. ALDO R. CASTANEDA
number of extraneous factors added to the overall operative mortality. Finally, postoperative measurements in 65 of these patients showed that more than 80% had no or only minimal residual gradients. Four patients with gradients higher than 60 mm Hg across the right ventricular outflow tract had pulmonary atresia. We now advocate the use of conduits in this group of patients. DR. FREDERICK A. CRAWFORD, J R . : (Charleston, sc):I enjoyed this presentation very much and agree with its conclusions. Since 1978, I have operated on 50 consecutive patients with tetralogy of Fallot, 6 of whom have died. Mortality was significantly higher in those children less than 1 year of age. All 6 deaths occurred in the 31 patients who required transannular patching. There were no deaths in 19 patients who did not require transannular patching, a significant difference. It is clear that infants less than 1 year of age can undergo successful correction of tetralogy of Fallot, but the risk is increased, especially in those who require transannular patching. After analysis of the data hom the University of Alabama and early data from this series, I adopted a policy in 1980 of palliative shunting for infants less than 1 year of age who were predicted to require a transannular patch. There have been no operative deaths in this series since that time. I have two questions for the authors. First, our pediatric cardiologists frequently use propranolol as palliation, and in some infants the need for a palliative shunt can be avoided. Has this been useful for you? Second, in those patients in whom shunts are placed, is the time of total correction based on symptoms or age?
My colleagues and I appreciate the comments of the discussants. To Dr. Castaneda, our appreciation for his remarks, especially for pointing out that a preliminary shunt probably does not influence whether or not a transannular patch will be needed in the later repair. Our operative mortality in patients less than 1 year old was almost double that of patients older than l year. This may have been influenced more by the deleterious effect of cardiopulmonary bypass and other nonspecific factors than by the use of a transannular patch, although transannular patch reconstruction undoubtedly exposes the heart to greater stress than does closing the right ventricle primarily. We do not measure right ventricular pressures in our patients and cannot comment on that particular question. We appreciate Dr. Crawford‘s experience, which mirrors our own. Our cardiologists have begun to use propranolol in the younger patients to prevent symptoms until an older age, although the number of patients in our series is too small to permit a comparison. In most instances if a patient receives a shunt before the age of 6 months, minor symptomatology such as mild cyanosis will appear when he or she is 2 to 5 years old, and correction is performed at that time. DR. HAMMON: