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A technique for correction of truncus arteriosus types I and II without extracardiac conduits
J
THORAC CARDIOVASC SURG
1990;99:364-9
A technique for correction of truncus arteriosus types I and II without extracardiac conduits A new corrective operation for truncus arteriosus without tbe use of an extracardiac conduit was performed in seven patients with truncus type I (six patients) or type Il (one patient) aged from 2 to 9 months. The common truncus arteriosus was septated with a patch into aortic and pulmonary segments and the ventricular septal defect was closed through a ventriculotomy. A direct anastomosis between the pulmonary arteries and tbe right ventricle was performed, tbe anterior waD being constructed with a patch with a monocusp valve. There was one death in the immediate postoperative period. In the surviving six patients tbe postoperative right ventricularlleft ventricular peak systolic pressure ratio was less than 0.51 in five and 0.60 in one with a residual ventricular septal defect. All are in functional class I between 1 and 14 months after tbe operation. On tbe basis of these results, we propose this technique for patients with truncus type I or Il in tbe first year of life.
Miguel Barbero-Marcial, MD. Arlindo Riso, MD, Edmar Atik, MD, and Adib Jatene, MD.
Sao Paulo. Brazil
h e mortality rate for patients with truncus arteriosus is high in the first months of life. I As a result, there is general agreement that early surgical treatment is necessary. Palliative operations restricting pulmonary flow yield high morbidity and mortality rates.? Early correction with an extracardiac valved conduit is a significant improvement over the palliative procedure. However, a considerable surgical risk and the necessity of replacing the conduit as the child grows or in case of obstruction are the main disadvantages.' In this paper a new corrective technique is presented that avoids the use of extracardiac conduits. Patients and methods Patients. Seven consecutive patients with truncus arteriosus type I or II underwent a corrective operation at the Heart Institute between Aug. 8, 1987, and July 20, 1988 (Table I). The patients weighed 3.2 to 6.4 kg (mean 4.7) and their ages at operation ranged from 2 to 9 months. All patients had signs and symptoms of severe congestive insufficiency and cyanosis. The
From the University of Sao Paulo Medical School, Heart Institute, Sao Paulo, Brazil. Received for publication Sept. 20, 1988. Accepted for publication June 12, 1989. Address for reprints: Miguel Barbero-Marcial, MD, Instituto do Coracao, Av. Dr. Eneas de Carvalho Aguiar, 44, Cerqueira Cesar, sao Paulo, SP-CEP: 05403, Brasil.
12/1/15529
364
preoperative echocardiographic study revealed truncus arteriosus type I in six patients and type II in one patient. This last patient was the only one subjected to preoperative catheterization. and the diagnosis of truncus arteriosus type II was confirmed. The postoperative evaluation was done through the analysis of clinical findings, conventional catheterization, and cross-sectional and Doppler echocardiographic studies. The echo studies were routinely performed 48 hours after the operation, at the time of discharge, and every 3 months thereafter. The studies included systematic searching for residual anatomic defects and regurgitant jets in both ventricular outflows tracts. Flow velocities were measured across the monocusp valve and distal to the pulmonary arteries. Flow velocities were also recorded in the ascending aorta. Right and left ventricular volume and performance were assessed as part of the study. All measurements of flow velocity were compared with those of normal children." Surgical technique. Through a midline incision, the pulmonary arteries were widely dissected and mobilized. The venae cavae were cannulated and the aortic cannula was placed near the emergence of the brachiocephalic trunk. After the start of cardiopulmonary bypass, the tapes placed around the pulmonary arteries were snugged, the cardioplegic solution was injected, and the left atrium and ventricle were drained through the foramen ovale or the atrial septum. In the six patients with truncus type I, a longitudinal incision was made in the left pulmonary artery near its anterosuperior aspect (Fig. I, A). This incision was extended vertically in the direction of the left sinus of Valsalva of the common trunk. After identification of the right pulmonary artery orifice and the left coronary artery ostium, a pericardial patch was sutured so as to divide the truncus arteriosus into two portions-aorta and pulmonary artery. This was done by starting the suture near the truncal valve ring and leaving the left sinus of Valsalva in the pulmonary component (Fig. I, B). The posterior suture of the patch was placed between the left coronary ostium and the or-
Volume 99 Number 2 February 1990
Truncus arteriosus 3 6 5
Table I. Pertinent clinical features Age
Truncus type
Preop. truncal valve incompetence (echo)
(rna)
Weight (kg)
2
3.9
Moderate
2
8
6.4
Trivial
3
9
3.9
None
4
8
4.5
Trivial
5
6
3.5
6
4
6.0
Trivial
7
3
3.2
None
Patient
II
Procedure
Moderate; also restrictive VSD and origin of common trunk from RV
Direct anastomosis RV-PT., closureof VSD Direct anastomosis, RV-PT; closure of VSD Direct anastomosis; enlargement of VSD; tunnel LV--{;Qmmon trunk Direct anastomosis RV-PT; closureof VSD Enlargement of VSD; tunnel LV-common trunk; interposition of LA Appendage between LPA and RV Direct anastomosis, RV-PT; closureof VSD Direct anastomosis, RV-PT; closureof VSD
Follow-up length and functional class (NYHA)
Well 14 mo postop.; class I Well II mo postop.; class I Well 7 mo postop.; class I Well 4 mo postop.; class I Sudden death 24 hr postop.
Well 2 mo postop.; class I Well I mo postop.; class I
RV. Right ventricle; PT, pulmonary trunk; VSD, ventricular septal defect; LV, left ventricle, LA, left atrial; LPA, left pulmonary artery.
igin of the right pulmonary artery. Care was taken to ensure that the patch was not too large; otherwise, the greater aortic pressure could push the patch against the right pulmonary artery orifice and cause obstruction. The right ventricle was then incised immediately under the left sinus of Valsalva, the incision following obliquely in an inferior and leftward course. The muscular trabeculae usually present in the extremities of the incision were sectioned. The ventricular septal defect was closed with a bovine pericardial patch. In one patient (case 3), the anterosuperior portion of a restrictive ventricular septal defect was enlarged I ern, After that, the lower edge of the incision in the left pulmonary artery was pushed down and sutured with separated U stitches to the left superior oblique edge of the ventriculotomy, the resulting suture line being almost horizontal (Fig. I, C). Next, a bovine pericardial patch, with a pericardial monocusp valve already attached to its undersurface, was sutured to the arterial and ventricular edges to construct the anterior wall of the new right ventricular-pulmonary arterial outflow tract (Fig. I, D and E). In one patient (case 5) with truncus arteriosus type II, a few technical variations were used (Fig. 2). The pulmonary arteries, arising from the posterior aspect to the common trunk, were separated from this trunk, by insertion of a bovine pericardial patch. The ventricular septal defect, restrictive in relation to the truncal anulus, was enlarged anterosuperiorly. Because of the great dextroposition of the trunk, the left ventricular-neoaortic tract was constructed with a double patch, one inferior and the other superior, the resulting angle along the suture line bulging into the right ventricular cavity. Because of the distance between the left pulmonary artery and the ventriculotomy, the left atrial appendage was interposed to construct the posterior wall of the new pulmonary trunk artery. The anterior wall was formed in the same way as in the previous patients, that is, with a bovine pericardial patch having a monocusp valve.
Results There was one postoperative death (patient 5). In this patient the intraoperative right ventricular/left ventricular peak systolic pressure ratio after bypass was 0.52. The initial 24 hours in the postoperative period were free of complications, with adequate cardiac output and normal sinus rhythm. However, after that period the patient had an irreversible cardiac arrest. Autopsy revealed necrosis of the His bundle and of its two branches; the atrioventricular node and its artery, a branch of the right coronary artery, were normal. No patient had low cardiac output or other postoperative complications after the surgical procedure. Six patients were discharged from the hospital and remain free of symptoms after a postoperative period of 1 to 14 months. These patients have been followed up by means of echocardiographic study. Cross-sectional echocardiography showed normal right and left ventricular diameters and function. The monocusp valve appeared to be well placed and performing normally (Fig. 3). Pulmonary regurgitation was detected by pulsed/ continuous-wave Doppler examination in all six patients, but the regurgitation was considered to be moderate to important in only one of them. In the remaining five patients mild alterations were detected. Subsequent Doppler assessments have not revealed increasing regurgitation. No significative obstruction was detected at the level of the right ventricular outflow tract across the monocusp
366
The Journal of Thoracic and Cardiovascular
Barbero-Marcial et al.
Surgery
!III
.~
..........
~(
.
B ":,_, .J . ,. ~ - - .- . · .,
1C
10 Fig. 1. Operative technique. A, Type I truncus arteriosus. The proposed incision is indicated by the dotted lines. B, Division of the truncus into the aorta and pulmonary arteries by the insertion of the bovine pericardial patch, C, Closure of the ventricular septal defect and the posterior anastomosis with interrupted sutures. D, The inset shows the pericardial patch being sewn into place. The pericardial monocusp was sewn to the inner side of the patch before insertion was begun, as can be seen. The dashed line in the main drawing represents the suture line between the monocusp and patch, E, Correct position of the monocusp valve during diastole is shown.
valve and pulmonary anastomosis. Complete Doppler echocardiographic data of six patients are shown in Table II. Five patients were subjected to heart catheterization 15 to 4~ days postoperatively (Table III). The right ventricular Ileft ventricular peak systolic ratio was moderately
elevated in only one patient (case 2), who had a small residual ventricular septal defect. There were no significant gradients between the right ventricle and the pulmonary arteries. No shunts were evident in any patient other than patient 2, and there was no angiographic evidence of distortion of the right or left pulmonary arteries (Fig. 4).
Volume 99 Number 2 February 1990
Truncus arteriosus
Fig. 2. Operative technique for truncus arteriosus type I I. In this case the left atrial appendage was interposed between the left pulmonary artery and the right ventricle to construct the posterior wall of the new pulmonary trunk.
367
Fig. 3. Postoperative echocardiogram in patient 3. Short-axis cut at the level of ventriculoarterial valves shows the monocusp valve well closed in diastole. RA, Right atrium; RV, right ventricle; Ao, aorta; MeV, monocusp valve; PT, pulmonary trunk.
Table II. Postoperative Doppler echocardiographic data Late follow-up
Patient
(mot
I 2 3 4 6 7
14 II 7 4 2 I
Pulmonary regurgitation
PA peak flow velocities (cmlsec)
Aortic regurgitation
Aortic peak flow velocities (em/sec)
210 125 110 130 112 100
Moderate Trivial
160 142 130 134 128 120
Important Moderate Trivial Moderate Trivial Trivial
None Trivial Trivial Trivial
Residual defects
LVEF 0.87 0.77 0.82 0.79 0.83 0.79
Small VSD
PA. Pulmonary artery: l.YEF. left ventricular ejection fraction: YSD. ventricular septal defect.
Table III. Early postoperative catheterization data in jive patients* Pressure
(111111
Hg]
Patient
RA
RV
LPA
RPA
LV
Ao
47/8 68/11 35/5 47/3 45/9
38/0 60/3 31/3
39/0 39/14 30/4 33/0 50/19
102/3 113/10 74/6 98/4 89/7
95/70
2
V = 3. a = 6.5 V=7.a=9.7 V = 2. a = 4. 3
3 4 6
5 8
64/35 80/60 83/60
Oxygen saturation (%)
RV/LV peak systolic ratio
RA
RV
RPA
LV
Ao
0.49 0.60 0.47 0.48 0.51
66 68 60 69 67
64 65 60 69 69
65 73 69 66 64.5
90.5 95 96
95 93
92 98
RA. right atrium: RV. right ventricle; l.PA. lcvt pulmonary artery; RPA. right pulmonary artery; l. V. left ventricle; Ao. aorta. The LVlAo and the RYIPA pressure measurements were not made simultaneously.
'Catheterization done IS to 47 days postoperatively.
Discussion The use of extracardiac conduits permitted the repair of several complex congenital cardiac anomalies.' However, when used in neonates and low-weight infants, seri-
ous immediate and late problems are frequent. In the patient with truncus arteriosus, several factors related to the anomaly render the insertion of the conduit difficult. Poor weight gain, cardiomegaly, and dilatation of the common
368
Barbero-Marcial et al.
Fig. 4. Postoperative angiograms in patient 3. The upper frames show the right ventricular and pulmonary arterial angiograms; the lower frames show the left ventricular and aortic angiograms. trunk are factors restricting placement of the conduit, as are the presence of the left lung, the common trunk, and the sternum. These factors may lead to the use of a smaller conduit than necessary or to compression of the conduit by the sternum. On the other hand, the valvular anulus of the conduits may compress the left coronary artery. At the level of the distal anastomosis, the conduits may distort the thin-walled pulmonary arteries. It is inevitable that the patient will outgrow the conduit. Valvular calcification with stenosis in Dacron conduits, stenosis in the proximal anastomosis, and stenosis in the tube itself are frequently observed late complications. Even fresh aortic homografts may undergo late postoperativecalcification, which compounds the problems oflack of availability. Direct ventriculopulmonary anastomosis permits the whole area of the common trunk, the left pulmonary artery, and the right ventricle to be occupied. In this manner, the right ventricular-left pulmonary arterial connection can be larger without the patch bulging outside the cardiac contour. The possibility of postoperative bleeding
The Journal of Thoracic and Cardiovascular Surgery
seems to decrease with the use of this technique, because the only external suture lines are those corresponding to the pulmonary circulation. The proposed correction does not differ considerably from that usually used in the correction of tetralogy of Fallot with annular and pulmonary trunk hypoplasia necessitating transannular patches. The probability of late pulmonary stenosis is minimized, because the posterior wall of the anastomosis is constructed with the patient's own tissues, which keep their potential for growth. A few attempts at correction of the common trunk without extracardiac conduits have been reported'v? but have failed to show good results. Despite the use of a monocusp valve, pulmonary insufficiency was considered responsible for the poor results. By contrast, Peetz and associates," using nonvalved extracardiac conduits for correction of truncus in the neonate, concluded that these conduits can provide good long-term results, despite the residual pulmonary insufficiency. In our opinion, because of the increased pulmonary arteriolar resistance in these patients, the insertion of a monocusp is particularly necessary in the early postoperative period, until progressive normalization of the pulmonary arteries has occurred. This monocusp must be large enough to occlude the largest possible area of the ventriculopulmonary anastomosis during diastole. The valve must be inserted in a high position, at the arteriallevei, in such a manner that, during closure, its free margin is set against the posterior spur corresponding to the ventriculopulmonary anastomosis (Fig. 1, E). The cause of death in patient 5 was probably related to the septal infarction and to necrosis of the His bundle and its branches; the essence of the arterial supply to the atrioventricular conduction system is its duality." From its origin at the crux, the nodal artery reaches the atrioventricular node and sometimes-there are major individual variations-supplies the penetrating atrioventricular bundle. The second source of arterial blood supply to the junctional area is the first or the second septal perforating artery of the anterior descending artery. Depending on anatomic variations, these perforating arteries can be the exclusive blood supply of the penetrating bundle and its branches. This serious complication, the consequence of anterior septal enlargement of the ventricular septal defect, calls our attention to the risk of septal resection, at least when performed in patients with truncus type ventricular septal defect. From our point of view, the proposed technique is best suited to the majority of neonates and infants with truncus arteriosus type I or 11-86% oftruncus cases 1°-with congestive cardiac failure and low body weight. In this group palliative banding of the pulmonary arteries or
Volume 99 Number 2 February 1990
correction with extracardiac conduits is followed by immediate and late morbidity and mortality. On the basis of clinical, hemodynamic, and Doppler echocardiographic results, the described technique may be an adequate choice in this group of patients. However, a longer follow-up is necessary to evaluate the late results properly.
Addendum Since completion of this manuscript two additional operations with the proposed technique for truncus arteriosus type I have been performed. The postoperativecourse was uneventful and the early postoperative echocardiographic and heart catheterization results showed results similar to those described for the initial series. We thank Prof. Dr. Delmont Bittencourt for his advice and criticalassessmentof the manuscript and Ms. Ana Maria Vilela da Motta for preparation of the manuscript. REFERENCES J. Van Praagh R, Van Praagh S. The anatomy of common aorticopulmonary trunk (truncus arteriosus communis) and its embryologic implications: a study of 57 necropsy cases.Am J Cardiol 1965;16:406-25. 2. Singh AK, de Leval MR, Pincott JR, Stark J. Pulmonary artery banding for truncus arteriosus in the first year of life. Circulation 1976;54(Pt 2):III 17-9.
Truncus arteriosus 3 6 9
3. Agarwal KC, Edwards WD, Feldt RH, Danielson GK, Puga FJ, McGoon DC. Clinicopathological correlates of obstructed right-sided porcine-valved extracardiac 'conduits. J THORAC CARDIOVASC SURG 1981 ;81 :591-60J. 4. Wilson N, Goldberg SJ, Dickson OF. Normal intracardiac and great artery blood velocity measurements by pulsed Doppler echocardiography. Br Heart J 1985;53:451-8. 5. McGoon DC, Wallace RB, Danielson GK. The Rastelli operation: its indications and results. J THORAC CARDl0VASC SURG 1973;65:65-75. 6. Lecompte I, Neveux JY, Leca F, et al. Reconstruction of the pulmonary outflow tract without prosthetic conduit. J THORAC CARDIOVASC SURG 1982;84:727-33. 7. Bailey LL, Petry EL, DoroshowRW, Jacobson JG, Wareham EE. Biologic reconstruction of the right ventricular outflow tract: preliminary experimental analysis and clinical application in a neonate with type I truncus arteriosus. J THORAC CARDIOVASC SURG 1981 ;82:779-84. 8. Peetz OJ Jr, Spicer RL, Crowley DC, Sloan H, Behrendt OM. Correction of truncus arteriosus in the neonate using a nonvalved conduit. J THORAC CARDIOVASC SURG 1982; 83:742-6. 9. Davies MJ, Anderson RH, Becker AE. Bloodsupply of the conduction system of the heart. London: Butterworths, 1983:74-80. 10. Kirklin JW, Barratt-Boyes BG: Truncus arteriosus. In: Cardiac surgery. New York: John Wiley, 1986:913.
THORAC CARDIOVASC SURG
1990;99:364-9
A technique for correction of truncus arteriosus types I and II without extracardiac conduits A new corrective operation for truncus arteriosus without tbe use of an extracardiac conduit was performed in seven patients with truncus type I (six patients) or type Il (one patient) aged from 2 to 9 months. The common truncus arteriosus was septated with a patch into aortic and pulmonary segments and the ventricular septal defect was closed through a ventriculotomy. A direct anastomosis between the pulmonary arteries and tbe right ventricle was performed, tbe anterior waD being constructed with a patch with a monocusp valve. There was one death in the immediate postoperative period. In the surviving six patients tbe postoperative right ventricularlleft ventricular peak systolic pressure ratio was less than 0.51 in five and 0.60 in one with a residual ventricular septal defect. All are in functional class I between 1 and 14 months after tbe operation. On tbe basis of these results, we propose this technique for patients with truncus type I or Il in tbe first year of life.
Miguel Barbero-Marcial, MD. Arlindo Riso, MD, Edmar Atik, MD, and Adib Jatene, MD.
Sao Paulo. Brazil
h e mortality rate for patients with truncus arteriosus is high in the first months of life. I As a result, there is general agreement that early surgical treatment is necessary. Palliative operations restricting pulmonary flow yield high morbidity and mortality rates.? Early correction with an extracardiac valved conduit is a significant improvement over the palliative procedure. However, a considerable surgical risk and the necessity of replacing the conduit as the child grows or in case of obstruction are the main disadvantages.' In this paper a new corrective technique is presented that avoids the use of extracardiac conduits. Patients and methods Patients. Seven consecutive patients with truncus arteriosus type I or II underwent a corrective operation at the Heart Institute between Aug. 8, 1987, and July 20, 1988 (Table I). The patients weighed 3.2 to 6.4 kg (mean 4.7) and their ages at operation ranged from 2 to 9 months. All patients had signs and symptoms of severe congestive insufficiency and cyanosis. The
From the University of Sao Paulo Medical School, Heart Institute, Sao Paulo, Brazil. Received for publication Sept. 20, 1988. Accepted for publication June 12, 1989. Address for reprints: Miguel Barbero-Marcial, MD, Instituto do Coracao, Av. Dr. Eneas de Carvalho Aguiar, 44, Cerqueira Cesar, sao Paulo, SP-CEP: 05403, Brasil.
12/1/15529
364
preoperative echocardiographic study revealed truncus arteriosus type I in six patients and type II in one patient. This last patient was the only one subjected to preoperative catheterization. and the diagnosis of truncus arteriosus type II was confirmed. The postoperative evaluation was done through the analysis of clinical findings, conventional catheterization, and cross-sectional and Doppler echocardiographic studies. The echo studies were routinely performed 48 hours after the operation, at the time of discharge, and every 3 months thereafter. The studies included systematic searching for residual anatomic defects and regurgitant jets in both ventricular outflows tracts. Flow velocities were measured across the monocusp valve and distal to the pulmonary arteries. Flow velocities were also recorded in the ascending aorta. Right and left ventricular volume and performance were assessed as part of the study. All measurements of flow velocity were compared with those of normal children." Surgical technique. Through a midline incision, the pulmonary arteries were widely dissected and mobilized. The venae cavae were cannulated and the aortic cannula was placed near the emergence of the brachiocephalic trunk. After the start of cardiopulmonary bypass, the tapes placed around the pulmonary arteries were snugged, the cardioplegic solution was injected, and the left atrium and ventricle were drained through the foramen ovale or the atrial septum. In the six patients with truncus type I, a longitudinal incision was made in the left pulmonary artery near its anterosuperior aspect (Fig. I, A). This incision was extended vertically in the direction of the left sinus of Valsalva of the common trunk. After identification of the right pulmonary artery orifice and the left coronary artery ostium, a pericardial patch was sutured so as to divide the truncus arteriosus into two portions-aorta and pulmonary artery. This was done by starting the suture near the truncal valve ring and leaving the left sinus of Valsalva in the pulmonary component (Fig. I, B). The posterior suture of the patch was placed between the left coronary ostium and the or-
Volume 99 Number 2 February 1990
Truncus arteriosus 3 6 5
Table I. Pertinent clinical features Age
Truncus type
Preop. truncal valve incompetence (echo)
(rna)
Weight (kg)
2
3.9
Moderate
2
8
6.4
Trivial
3
9
3.9
None
4
8
4.5
Trivial
5
6
3.5
6
4
6.0
Trivial
7
3
3.2
None
Patient
II
Procedure
Moderate; also restrictive VSD and origin of common trunk from RV
Direct anastomosis RV-PT., closureof VSD Direct anastomosis, RV-PT; closure of VSD Direct anastomosis; enlargement of VSD; tunnel LV--{;Qmmon trunk Direct anastomosis RV-PT; closureof VSD Enlargement of VSD; tunnel LV-common trunk; interposition of LA Appendage between LPA and RV Direct anastomosis, RV-PT; closureof VSD Direct anastomosis, RV-PT; closureof VSD
Follow-up length and functional class (NYHA)
Well 14 mo postop.; class I Well II mo postop.; class I Well 7 mo postop.; class I Well 4 mo postop.; class I Sudden death 24 hr postop.
Well 2 mo postop.; class I Well I mo postop.; class I
RV. Right ventricle; PT, pulmonary trunk; VSD, ventricular septal defect; LV, left ventricle, LA, left atrial; LPA, left pulmonary artery.
igin of the right pulmonary artery. Care was taken to ensure that the patch was not too large; otherwise, the greater aortic pressure could push the patch against the right pulmonary artery orifice and cause obstruction. The right ventricle was then incised immediately under the left sinus of Valsalva, the incision following obliquely in an inferior and leftward course. The muscular trabeculae usually present in the extremities of the incision were sectioned. The ventricular septal defect was closed with a bovine pericardial patch. In one patient (case 3), the anterosuperior portion of a restrictive ventricular septal defect was enlarged I ern, After that, the lower edge of the incision in the left pulmonary artery was pushed down and sutured with separated U stitches to the left superior oblique edge of the ventriculotomy, the resulting suture line being almost horizontal (Fig. I, C). Next, a bovine pericardial patch, with a pericardial monocusp valve already attached to its undersurface, was sutured to the arterial and ventricular edges to construct the anterior wall of the new right ventricular-pulmonary arterial outflow tract (Fig. I, D and E). In one patient (case 5) with truncus arteriosus type II, a few technical variations were used (Fig. 2). The pulmonary arteries, arising from the posterior aspect to the common trunk, were separated from this trunk, by insertion of a bovine pericardial patch. The ventricular septal defect, restrictive in relation to the truncal anulus, was enlarged anterosuperiorly. Because of the great dextroposition of the trunk, the left ventricular-neoaortic tract was constructed with a double patch, one inferior and the other superior, the resulting angle along the suture line bulging into the right ventricular cavity. Because of the distance between the left pulmonary artery and the ventriculotomy, the left atrial appendage was interposed to construct the posterior wall of the new pulmonary trunk artery. The anterior wall was formed in the same way as in the previous patients, that is, with a bovine pericardial patch having a monocusp valve.
Results There was one postoperative death (patient 5). In this patient the intraoperative right ventricular/left ventricular peak systolic pressure ratio after bypass was 0.52. The initial 24 hours in the postoperative period were free of complications, with adequate cardiac output and normal sinus rhythm. However, after that period the patient had an irreversible cardiac arrest. Autopsy revealed necrosis of the His bundle and of its two branches; the atrioventricular node and its artery, a branch of the right coronary artery, were normal. No patient had low cardiac output or other postoperative complications after the surgical procedure. Six patients were discharged from the hospital and remain free of symptoms after a postoperative period of 1 to 14 months. These patients have been followed up by means of echocardiographic study. Cross-sectional echocardiography showed normal right and left ventricular diameters and function. The monocusp valve appeared to be well placed and performing normally (Fig. 3). Pulmonary regurgitation was detected by pulsed/ continuous-wave Doppler examination in all six patients, but the regurgitation was considered to be moderate to important in only one of them. In the remaining five patients mild alterations were detected. Subsequent Doppler assessments have not revealed increasing regurgitation. No significative obstruction was detected at the level of the right ventricular outflow tract across the monocusp
366
The Journal of Thoracic and Cardiovascular
Barbero-Marcial et al.
Surgery
!III
.~
..........
~(
.
B ":,_, .J . ,. ~ - - .- . · .,
1C
10 Fig. 1. Operative technique. A, Type I truncus arteriosus. The proposed incision is indicated by the dotted lines. B, Division of the truncus into the aorta and pulmonary arteries by the insertion of the bovine pericardial patch, C, Closure of the ventricular septal defect and the posterior anastomosis with interrupted sutures. D, The inset shows the pericardial patch being sewn into place. The pericardial monocusp was sewn to the inner side of the patch before insertion was begun, as can be seen. The dashed line in the main drawing represents the suture line between the monocusp and patch, E, Correct position of the monocusp valve during diastole is shown.
valve and pulmonary anastomosis. Complete Doppler echocardiographic data of six patients are shown in Table II. Five patients were subjected to heart catheterization 15 to 4~ days postoperatively (Table III). The right ventricular Ileft ventricular peak systolic ratio was moderately
elevated in only one patient (case 2), who had a small residual ventricular septal defect. There were no significant gradients between the right ventricle and the pulmonary arteries. No shunts were evident in any patient other than patient 2, and there was no angiographic evidence of distortion of the right or left pulmonary arteries (Fig. 4).
Volume 99 Number 2 February 1990
Truncus arteriosus
Fig. 2. Operative technique for truncus arteriosus type I I. In this case the left atrial appendage was interposed between the left pulmonary artery and the right ventricle to construct the posterior wall of the new pulmonary trunk.
367
Fig. 3. Postoperative echocardiogram in patient 3. Short-axis cut at the level of ventriculoarterial valves shows the monocusp valve well closed in diastole. RA, Right atrium; RV, right ventricle; Ao, aorta; MeV, monocusp valve; PT, pulmonary trunk.
Table II. Postoperative Doppler echocardiographic data Late follow-up
Patient
(mot
I 2 3 4 6 7
14 II 7 4 2 I
Pulmonary regurgitation
PA peak flow velocities (cmlsec)
Aortic regurgitation
Aortic peak flow velocities (em/sec)
210 125 110 130 112 100
Moderate Trivial
160 142 130 134 128 120
Important Moderate Trivial Moderate Trivial Trivial
None Trivial Trivial Trivial
Residual defects
LVEF 0.87 0.77 0.82 0.79 0.83 0.79
Small VSD
PA. Pulmonary artery: l.YEF. left ventricular ejection fraction: YSD. ventricular septal defect.
Table III. Early postoperative catheterization data in jive patients* Pressure
(111111
Hg]
Patient
RA
RV
LPA
RPA
LV
Ao
47/8 68/11 35/5 47/3 45/9
38/0 60/3 31/3
39/0 39/14 30/4 33/0 50/19
102/3 113/10 74/6 98/4 89/7
95/70
2
V = 3. a = 6.5 V=7.a=9.7 V = 2. a = 4. 3
3 4 6
5 8
64/35 80/60 83/60
Oxygen saturation (%)
RV/LV peak systolic ratio
RA
RV
RPA
LV
Ao
0.49 0.60 0.47 0.48 0.51
66 68 60 69 67
64 65 60 69 69
65 73 69 66 64.5
90.5 95 96
95 93
92 98
RA. right atrium: RV. right ventricle; l.PA. lcvt pulmonary artery; RPA. right pulmonary artery; l. V. left ventricle; Ao. aorta. The LVlAo and the RYIPA pressure measurements were not made simultaneously.
'Catheterization done IS to 47 days postoperatively.
Discussion The use of extracardiac conduits permitted the repair of several complex congenital cardiac anomalies.' However, when used in neonates and low-weight infants, seri-
ous immediate and late problems are frequent. In the patient with truncus arteriosus, several factors related to the anomaly render the insertion of the conduit difficult. Poor weight gain, cardiomegaly, and dilatation of the common
368
Barbero-Marcial et al.
Fig. 4. Postoperative angiograms in patient 3. The upper frames show the right ventricular and pulmonary arterial angiograms; the lower frames show the left ventricular and aortic angiograms. trunk are factors restricting placement of the conduit, as are the presence of the left lung, the common trunk, and the sternum. These factors may lead to the use of a smaller conduit than necessary or to compression of the conduit by the sternum. On the other hand, the valvular anulus of the conduits may compress the left coronary artery. At the level of the distal anastomosis, the conduits may distort the thin-walled pulmonary arteries. It is inevitable that the patient will outgrow the conduit. Valvular calcification with stenosis in Dacron conduits, stenosis in the proximal anastomosis, and stenosis in the tube itself are frequently observed late complications. Even fresh aortic homografts may undergo late postoperativecalcification, which compounds the problems oflack of availability. Direct ventriculopulmonary anastomosis permits the whole area of the common trunk, the left pulmonary artery, and the right ventricle to be occupied. In this manner, the right ventricular-left pulmonary arterial connection can be larger without the patch bulging outside the cardiac contour. The possibility of postoperative bleeding
The Journal of Thoracic and Cardiovascular Surgery
seems to decrease with the use of this technique, because the only external suture lines are those corresponding to the pulmonary circulation. The proposed correction does not differ considerably from that usually used in the correction of tetralogy of Fallot with annular and pulmonary trunk hypoplasia necessitating transannular patches. The probability of late pulmonary stenosis is minimized, because the posterior wall of the anastomosis is constructed with the patient's own tissues, which keep their potential for growth. A few attempts at correction of the common trunk without extracardiac conduits have been reported'v? but have failed to show good results. Despite the use of a monocusp valve, pulmonary insufficiency was considered responsible for the poor results. By contrast, Peetz and associates," using nonvalved extracardiac conduits for correction of truncus in the neonate, concluded that these conduits can provide good long-term results, despite the residual pulmonary insufficiency. In our opinion, because of the increased pulmonary arteriolar resistance in these patients, the insertion of a monocusp is particularly necessary in the early postoperative period, until progressive normalization of the pulmonary arteries has occurred. This monocusp must be large enough to occlude the largest possible area of the ventriculopulmonary anastomosis during diastole. The valve must be inserted in a high position, at the arteriallevei, in such a manner that, during closure, its free margin is set against the posterior spur corresponding to the ventriculopulmonary anastomosis (Fig. 1, E). The cause of death in patient 5 was probably related to the septal infarction and to necrosis of the His bundle and its branches; the essence of the arterial supply to the atrioventricular conduction system is its duality." From its origin at the crux, the nodal artery reaches the atrioventricular node and sometimes-there are major individual variations-supplies the penetrating atrioventricular bundle. The second source of arterial blood supply to the junctional area is the first or the second septal perforating artery of the anterior descending artery. Depending on anatomic variations, these perforating arteries can be the exclusive blood supply of the penetrating bundle and its branches. This serious complication, the consequence of anterior septal enlargement of the ventricular septal defect, calls our attention to the risk of septal resection, at least when performed in patients with truncus type ventricular septal defect. From our point of view, the proposed technique is best suited to the majority of neonates and infants with truncus arteriosus type I or 11-86% oftruncus cases 1°-with congestive cardiac failure and low body weight. In this group palliative banding of the pulmonary arteries or
Volume 99 Number 2 February 1990
correction with extracardiac conduits is followed by immediate and late morbidity and mortality. On the basis of clinical, hemodynamic, and Doppler echocardiographic results, the described technique may be an adequate choice in this group of patients. However, a longer follow-up is necessary to evaluate the late results properly.
Addendum Since completion of this manuscript two additional operations with the proposed technique for truncus arteriosus type I have been performed. The postoperativecourse was uneventful and the early postoperative echocardiographic and heart catheterization results showed results similar to those described for the initial series. We thank Prof. Dr. Delmont Bittencourt for his advice and criticalassessmentof the manuscript and Ms. Ana Maria Vilela da Motta for preparation of the manuscript. REFERENCES J. Van Praagh R, Van Praagh S. The anatomy of common aorticopulmonary trunk (truncus arteriosus communis) and its embryologic implications: a study of 57 necropsy cases.Am J Cardiol 1965;16:406-25. 2. Singh AK, de Leval MR, Pincott JR, Stark J. Pulmonary artery banding for truncus arteriosus in the first year of life. Circulation 1976;54(Pt 2):III 17-9.
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3. Agarwal KC, Edwards WD, Feldt RH, Danielson GK, Puga FJ, McGoon DC. Clinicopathological correlates of obstructed right-sided porcine-valved extracardiac 'conduits. J THORAC CARDIOVASC SURG 1981 ;81 :591-60J. 4. Wilson N, Goldberg SJ, Dickson OF. Normal intracardiac and great artery blood velocity measurements by pulsed Doppler echocardiography. Br Heart J 1985;53:451-8. 5. McGoon DC, Wallace RB, Danielson GK. The Rastelli operation: its indications and results. J THORAC CARDl0VASC SURG 1973;65:65-75. 6. Lecompte I, Neveux JY, Leca F, et al. Reconstruction of the pulmonary outflow tract without prosthetic conduit. J THORAC CARDIOVASC SURG 1982;84:727-33. 7. Bailey LL, Petry EL, DoroshowRW, Jacobson JG, Wareham EE. Biologic reconstruction of the right ventricular outflow tract: preliminary experimental analysis and clinical application in a neonate with type I truncus arteriosus. J THORAC CARDIOVASC SURG 1981 ;82:779-84. 8. Peetz OJ Jr, Spicer RL, Crowley DC, Sloan H, Behrendt OM. Correction of truncus arteriosus in the neonate using a nonvalved conduit. J THORAC CARDIOVASC SURG 1982; 83:742-6. 9. Davies MJ, Anderson RH, Becker AE. Bloodsupply of the conduction system of the heart. London: Butterworths, 1983:74-80. 10. Kirklin JW, Barratt-Boyes BG: Truncus arteriosus. In: Cardiac surgery. New York: John Wiley, 1986:913.