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Primary repair of interrupted aortic arch and severe aortic stenosis in neonates
J
THoRAc CARDIOVASC SURG
1987;93:539-45
Primary repair of interrupted aortic arch and severe aortic stenosis in neonates Two infants, aged 36 days old (Case 1) and 18 days old (Case 2) with interrupted aortic arch types B and A, respectively, and with severe aortic stenosis, were successfully operated on by use of pulsatile cardiopulmonary bypass. The great arteries were normaUy related in Case 1 and were transposed in Case 2. Repair involved the foUowing procedure: ligation of the patent ductus arteriosus, restoration of aortic continuity with an 8 nun polytetrafluoroethylene graft, placement of an internal patch to tunnel aU left ventricular blood from the left ventricle through the ventricular septal defect into the pulmonary artery in Case 1 and patch closure of the ventricular septal defect in Case 2, transection of the main pulmonary artery, anastomosis between the proximal pulmonary artery and the ascending aorta, and interposition of a valved conduit between the right ventricle and the distal pulmonary artery. The operative field could be approached easily through a median sternotomy. Postoperative cardiac catheterization revealed satisfactory anatomical and hemodynamic results in both cases.
Hisataka Yasui, M.D., Hideaki Kado, M.D., Eiichi Nakano, M.D., Kunihiro Yonenaga, M.D., Atsuo Mitani, M.D., Yukihiro Tomita, M.D., Hatsuo Iwao, M.D., Kaoru Yoshii, M.D., Yasuhiro Mizoguchi, M.D., and Hiroshi Sunagawa, M.D., Fukuoka, Japan
Interrupted aortic arch (lAA) is a rare but highly lethal anomaly in early infancy.':' Reparative operations must be used, but the surgical results are not satisfactory.5'15 Moreover, when IAA is associated with aortic stenosis, surgical management is more complex and difficult. This article presents our experience with primary repair of IAA associated with severe aortic stenosis. A new method of repair, which restores the continuity between the left ventricle and the ascending aorta, was employed in an infant with normally related great arteries. A safe method of cannulation for cardiopulmonary bypass in an infant with a small ascending aorta is presented. Case reports Between 1981 and 1985, nine patients younger than 3 months of age underwent operation for IAA at Fukuoka Children's Hospital. The first seven patients (except for
From the Divisions of Cardiovascular Surgery and Pediatrics, Fukuoka Children's Hospital Medical Center, Fukuoka, Japan. Received for publication March 12, 1986. Accepted for publication April 11, 1986. Address for reprints: Hisataka Yasui, M.D., Division of Cardiovascular Surgery, Fukuoka Children's Hospital Medical Center, 2-5-1, Tojin, Chuoku, Fukuoka 810, Japan.
one) had staged correction: In the first operation aortic continuity was restored with a 6 mm synthetic graft, with or without pulmonary artery banding, and in the second operation, 1 or 2 months later, the ventricular septal defect (VSD) was closed. There was one surgical death; the fifth patient, who had IAA type A plus VSD and underwent primary correction by use of cardiopulmonary bypass, died of a laceration of the ascending aorta at the arterial cannulation site. The last two patients had severe aortic stenosis associated with IAA and required relief of the stenosis in addition to repair of IAA. CASE L A male infant, weighing 2,970 gm at birth after an uncomplicated 40 week gestation, was noted to have tachypnea and a cardiac murmur shortly after birth. He was transferred to Fukuoka Children's Hospital at 33 days of age with a drip infusion of prostaglandin E I (PGE 1) (0.05 !J.g/ kg/min). On admission, he was mildly cyanotic. The respiratory rate was 80 breaths/min and the heart rate 160 beats/min. Systolic blood pressure was 60 mm Hg in the right arm and 65 mm Hg in the lower extremities. A Grade 2/6 systolic ejection murmur was audible along the left sternal border. Cardiac catheterization when the infant was 34 days old revealed lAA type B with an aberrant right subclavian artery, severe subvalvular and valvular aortic stenosis, a large confluent YSD, and a large patent ductus arteriosus (Fig. 1). When the infant was 36 days old (Jan. 19, 1985), median sternotomy was performed. The entire ascending aorta, the left
539
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Fig. 1. Patient 1. Preoperative left ventriculogram shows IAA type B in the frontal view (left) and a large confluent VSD and severe valvular and subvalvular aortic stenosis (arrow) in the lateral view (right).
carotid artery, and the main pulmonary artery and its bifurcation were mobilized. The dissection was extended along the ductus arteriosus to the descending aortas, as long as the condition of the patient allowed. Cardiopulmonary bypass was initiated with a single 18 Fr. venous cannula in the right atrium. Both great arteries were cannulated (Fig. 2). A 14 gauge intravenous catheter was inserted into the aorta for perfusion and a 10 Fr. Bardic arterial cannula was placed in the main pulmonary artery. At initiation of bypass, both right and left pulmonary arteries were occluded with a silk ligature (Fig. 2, A). The patient was cooled to 22° C rectal temperature with a pump flow rate of 120 ml/kg/rnin. The arterial line to the pulmonary artery was clamped and the flow rate was decreased to 30 ml/kg/min. A partial occluding clamp was placed on the descending aorta and the previously prepared 8 mm polytetrafluoroethylene (PTFE) graft with a side arm constructed of a 6 mm PTFE graft was anastomosed to the descending aorta in an end-to-side fashion (Fig. 2, B). The clamp on the arterial line to the pulmonary artery was removed and the flow rate was increased to 70 nil/kg/min. The ascending aorta was side-clamped and the proximal end of the 8 mm PTFE graft was anastomosed to the ascending aorta (Fig. 2, C). The flow rate was decreased to 30 ml/kg/rnin, and the arterial cannula to the pulmonary artery was clamped and removed, after ligation of the patent ductus arteriosus with two silk ligatures. An effective pulsatile flow was achieved by exchanging the 10 Fr. Bardic arterial cannula for a 12 Fr. cannula, which was inserted into the side arm of the interposed PTFE graft (Fig. 2, D) and individual venous cannulation was made (Fig. 2, D). The flow rate was elevated to 170 ml/kg/min (2.5 L/m'/min) and a pulsatile bypass pump (Kontron Instrument, Model 20) was started, with a pulse rate of 100 beats/min and a driving pressure of 350 mm Hg. The patient was gradually rewarmed. The arterial line to
the ascending aorta was clamped and disconnected from the 14 gauge intravenous catheter that was connected to a cardioplegic solution line. The ascending aorta was crossclamped and cold potassium cardioplegic solution (potassium concentration 20 mEq/L) was infused (Fig. 2, D). A longitudinal incision was made in the infundibulum of the right ventricle. A large VSD involved both the perimembranous and subpulmonary regions. An elliptical Teflon patch was sewn into place to direct all left ventricular blood from the left ventricle through the VSD into the pulmonary artery (Fig. 3, A). The pulmonary artery was transected at the site of previous arterial cannulation and its proximal end was sutured end to side to the ascending aorta (Fig. 3, A). A 14 mm Hancock valved conduit was interposed between the right ventriculotomy and the distal pulmonary artery (Fig. 3, B). The aorta was unclamped after completion of the conduit anastomosis (a total of 65 minutes of anoxia). When the patient was rewarmed to 34 ° C rectal temperature, the bypass was discontinued. The postoperative course was complicated by respiratory failure and temporary complete atrioventricular block, although normal sinus rhythm returned on the twelfth postoperative day. On the ninth postoperative day, a permanent pacemaker (Biotronic NEOS-M) was implanted. However, the generator was removed on the eighteenth postoperative day because of a pacemaker pocket infection. Thirty-five days after operation, the patient was weaned from mechanical ventilation. Cardiac catheterization was performed 8 months after operation and demonstrated excellent anatomical correction and hemodynamics (Table I). CASE 2. A male infant, weighing 3472 gm, was admitted when he was 11 days old for cyanosis and congestive heart failure. He had been delivered vaginally after a 38 week gestation; birth weight was 3,300 gm.
Volume 93 Number 4 April 1987
1AA and aortic stenosis in neonates
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Fig. 2. Arterial cannulation method for lAA with patent ductus arteriosus. A, The small intravenous catheter used as an arterial cannula does not tear and narrow the small ascending aorta. The descending aorta is perfused from the main pulmonary artery through the patent ductus arteriosus. B, The previously prepared 8 mm PTFE graft, with a side arm of 6 mm PTFE graft, was anastomosed to the descending aorta in a end-to-side fashion. C, With the ascending aorta side clamped, proximal anastomosis of the PTFE graft was completed. D, After restoration of the aortic continuity, only the arterial line into the side arm of the PTFE graft is sufficient for perfusion of the whole body; the intravenous catheter into the ascending aorta can then be used for cardioplegic infusion.
On admission, he was moderately cyanotic and tachypneic. Moderate hepatomegaly was present. The femoral pulses were easily palpable. A Grade 2/6 systolic ejection murmur was audible at the left upper sternal border. Measurement of arterial blood gas showed pH 7.04, oxygen tension 53 mm Hg, and base excess -18.0. Mechanical ventilation was instituted. On the infant's fifteenth day of life, cardiac catheterization revealed IAA type A with transposed great arteries, subvalvular aortic stenosis, a large perimembranous VSD, and a large patent ductus arteriosus (Fig. 4).
When the infant was 18 days old (April 19, 1985), a midsternal splitting incision was made. Cardiopulmonary bypass was instituted in the same manner as performed in Case I. An 8 mm PTFE graft, with a previously sewn-up side arm of a 6 mm PTFE graft, was interposed between the ascending aorta and the descending aorta. Through a vertical right ventriculotomy, a large perimembranous VSD was closed by a Teflon patch. The main pulmonary artery was divided and its proximal end was anastomosed to the ascending aorta in end-to-side fashion. The aortic valve was left in
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542 Yasui et al.
Surgery
Fig. 3. Schematic view of repair in Patient I. A, Internal tunnel patch was sewn into place and the proximal end of the main pulmonary artery was sutured end to side to the ascending aorta. B, Completion of repair. The side arm for arterial cannulation was tied with two silk ligatures.
Fig. 4. Preoperative right ventriculogram of Patient 2 shows IAA type A, subvalvular aortic stenosis (arrow), and a perimembranous YSD.
continuity with the right ventricle. A 14 mm Hancock valved conduit was interposed between the right ventriculotomy and the distal pulmonary artery. The postoperative course was uneventful, except for temporary left phrenic nerve palsy and prolonged dependence on mechanical ventilatory support, from which he was weaned on the twenty-first postoperative day. Cardiac catheterization was performed 2 months after the operation (Fig. 5 and Table I).
Discussion The operative results of IAA obtained so far are not satisfactory and controversy exists over the optimal surgical management for the patients involved, in terms of palliative or primary reparative procedures.r" Preoperative condition of the patient, intraoperative care (including anesthesia and cardiopulmonary
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Fig. 5. Postoperative left atriogram of Patient 2 shows smooth blood flow from the left ventricle to the proximal pulmonary artery and the ascending aorta. A small shunt (Qp/Qs = 1.2) exists.
Table I. Postoperative cardiac catheterization data Case 2
Case I Site
MPA RV RA SVC
Pressure (mm Hg) 37/15 (23)* 44/ 8 a= 6, v = 5 (3)
IVe
LA PAW FA
a= 14, v= 13 (9) 98/47 (66)
I
O2 sat. (%)
Pressure (mm Hg)
62.2 64.4 66.7 69.8 66.7
34/ 9 (17) 42/ 9 a = II, v = 12 (8)
93.0
I
O2 sat. (%) 66.7 66.7 69.8 72.8
a = 14, v = 15 (8)
91.0
83/50 (64)
95.6
Legend: MPA, Main pulmonary artery. RY, Right ventricle. RA, Right atrium. SYC, Superior venacava. IYC, Inferior vena cava. LA, Left atrium. PA W, Pulmonary artery wedge. FA, Femoral artery. 'Mean values indicated by parentheses.
bypass), surgical technique, and postoperative care all directly contribute to the surgical result. Surgical care, as well as surgical technique, has been greatly improved since the first successful palliative operation for IAA in the neonate, which was performed by Tyson, Harris, and Ngiem" in 1970. The advent of PGE 1 has dramatically changed the outlook for the neonates involved. Infusion of PGE} can significantly dilate the patent ductus arteriosus and allow diuresis and reversal of acidosis." The operation can be performed under optimal conditions, in which the patient will tolerate cardiopulmonary bypass. Some criticisms may arise in regard to palliative
interposition of the synthetic graft without cardiopulmonary bypass. In the case of a small ascending aorta, such as in IAA types Band C, there is limited room to apply a partial occluding vascular clamp, and cerebral blood flow may be compromised. Cerebral compromise may be prevented by applying a vascular clamp mainly to the left carotid artery, although this may result in a residual pressure gradient across the anastomosis. On the other hand, a small bite in the ascending aorta to maintain cerebral blood flow will allow use of only a small synthetic graft, which will become restrictive rather quickly as the patient grows.13. 14 To overcome congestive heart failure, it will be necessary to add pulmonary
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Yasui et al.
artery banding for the control of pulmonary arterial blood flow in most patients. However, the band may create or aggravate subaortic stenosis, as postulated by Van Praagh and associates" in 1971 and confirmed by Trusler and Freedom- in 1979. Therefore, not only in the case of subaortic stenosis, but also in the case of a conoventricular malalignment type of VSD, pulmonary artery banding would appear to be contraindicated and primary correction would be the treatment of choice. In patients with a small, thin-walled ascending aorta, there are some problems with instituting cardiopulmonary bypass. Because of the discontinuity of the aorta, the ascending aorta and the descending aorta must be perfused separately and their flow rates must be controlled. By use of cannulas of different sizes for the ascending aorta and the pulmonary artery (i.e., descending aorta), the flow rate through a Y-connected individual line is easily controlled, as in our cases. Moreover, the small cannula in the ascending aorta, a 14 gauge intravenous catheter in our cases, prevents dangerous tearing and postoperative narrowing of the thin, small aorta at the cannulation site (Fig. 2). After restoration of aortic continuity, only the arterial line to the pulmonary artery is sufficient for perfusion of the whole body during correction of an intracardiac anomaly. The intravenous catheter into the ascending aorta can then be used for cardioplegic infusion. In patients whose pulmonary artery is mobilized, as it was in our cases, an arterial cannula of optimal size can be easily placed into the newly built aortic arch through the side arm of the PTFE graft (Fig. 2, D). In most of the earlier cases of successful primary repair in infants, surface-induced profound hypothermia, combined with limited cardiopulmonary bypass and total circulatory arrest, was employed rather than conventional cardiopulmonary bypass. The time limit for circulatory arrest and the danger of brain damage compound the difficult operation. 18, 19 Recently, the cardiopulmonary bypass procedure has been progressively improved in technique, apparatus, and priming solution, which lessens its side effects. If such problems as previously mentioned are solved, a conventional cardiopulmonary bypass method will be far superior to the circulatory arrest method. A pulsatile bypass pump is a good adjunct for improvement of cardiopulmonary bypass physiologically.":" Indeed, a satisfactory result which showed an operative mortality of 3.6% and a mean duration of postoperative respiratory support of 5 days was obtained by use of high-flow cardiopulmonary bypass (2.5 Ljm 2jmin at 28° C rectal temperature) combined with a pulsatile bypass pump at Fukuoka Children's Hospital for a consecutive period of 2 years
(since January 1984) in 28 patients younger than 3 months old with complicated cardiac anomalies. In the two cases presented, a long period of postoperative respiratory support was needed. However, although the complex cardiopulmonary bypass might contribute to the patients' respirator dependency, the main causes were temporary complete atrioventricular block and subsequent pacemaker implantation through a left thoracotomy in Case 1 and temporary phrenic nerve palsy in Case 2. Severe aortic stenosis makes surgical management of IAA more complicated. To our knowledge, primary definitive repair for such combined cases has not been reported. Norwood and associatesv" reported good results with a staged operation; that is, placement of an apical-aortic conduit and pulmonary artery banding at the first stage, and closure of the VSD and removal of the pulmonary artery band at the second stage. In our experience, however, as shown in Case 1 (Fig. 3), it is possible to place an internal tunnel for subpulmonary VSD in most of the patients with normally related great arteries. This method can be employed even in patients with a diminutive ascending aorta, if the pulmonary valve is competent and the left ventricular performance is satisfactory, because the proximal pulmonary artery functions as the ascending aorta. A similar procedure was previously devised by Damus," Kaye," and Stansel" in complete transposition of the great vessels with VSD. This encouraged us to proceed. with a new approach for IAA (presented here), associated with severe aortic stenosis in patients with normally related great arteries, as well as in those with transposed great arteries. This approach seems to be simple in concept, compared with that of the apical-aortic conduit. However, it is difficult at this moment to determine which approach is superior because of insufficient long-term follow-up data. Either approach may be a valid option, depending upon the anatomy of the intracardiac anomalies.
Addendum Since submission of this article, three patients with lAA and VSD underwent primary repair by use of the same cardiopulmonary bypass technique as we have presented here. All are alive, and the mean duration of postoperative ventilatory support for them was 3 days. REFERENCES I, Roberts WC, Morrow AG, Braunwald E. Complete interruption of the aortic arch. Circulation 1962;26:3959. 2. Trusler GA, Freedom RM. Surgical approach to the managements of interruption of the aorta. In: Godman
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3.
4.
5.
6.
7.
8.
9.
10.
II.
12.
13.
14.
MJ, Marquis RM, eds. Paediatric cardiology, vol 2. Edinburgh: Churchill, Livingstone, 1979:268-73. Freedom RM, Brain HH, Esplugas E, Dische R, Rowe RD. Ventricular septal defect in interruption of aortic arch. Am J Cardiol 1977;39:572-82. Van Praagh R, Bernhard WF, Rosenthal A, Parisi LF, Fyler DC. Interrupted aortic arch: surgical treatment. Am J Cardiol 1971;27:200-11. Murphy DA, Lemire GG, Tessler L, Dunn GL. Correction of type B aortic arch interruption with ventricular and atrial septal defects in a three-day-old infant. J THORAC CARDIOVASC SURG 1973;65:882-6. Trusler GA, Izukawa T. Interrupted aortic arch and vestibular septal defect: direct repair through a median sternotomy incision in a 13-day-old infant. J THORAC CARDIOVASC SURG 1975;69:126-31. Muraoka R, Yokota M, Aoshima M, et al. Simplified method for total correction of interrupted aortic arch with ventricular septal defect in infancy. J THORAC CARDlOVASC SURG 1979;78:744-9. Bailey LL, Jacobano JG, Doroshow RW, Merritt WH, Petry EL. Anatomic correction of interrupted aortic arch complex in neonate. Surgery 1981;89:553-7. Moulton AL, Bowman FO Jr. Primary definitive repair of type B interrupted aortic arch, ventricular septal defect, and patent ductus arteriosus: early and late results. J THORAC CARDIOVASC SURG 1981;82:501-10. Norwood WJ, Lang P, Castaneda AR, Hougen TJ. Reparative operation for interrupted aortic arch with ventricular septal defect. J THORAC CARDIOVASC SURG 1983;86:832-7. Brunlin EA, Lock JE, Foker JE. Repair of type B interruption of the aortic arch: results and follow-up. J THORAC CARDIOVASC SURG 1983;86:920-5. Turley K. Cardiopulmonary bypass in interrupted aortic arch [Letter]. J THORAC CARDIOVASC SURG 1979; 77:798. Sturm JT, VanHiikeren DW, Borkat G. Surgical treatment of interrupted aortic arch in infancy with expanded polytetrafluoroethylene grafts. J THORAC CARDIOVASC SURG 1981;81:245-50. Fowler BN, Lucas SK, Razook JD, Thomson WM Jr, Williamed GR, Elkins RC. Interruption of the aortic
lAA and aortic stenosis in neonates 5 4 5
arch: experience in 17 infants. Ann Thorac Surg 1984;37:25-32. 15. Kron II, Rheuban KS, Carpenter MS, Nolan SP. Interrupted aortic arch: a conservative approach for the sick neonate. J THORAC CARDIOVASC SURG 1983;86:37-40. 16. Tyson KRT, Harris LC, Ngiem QX. Repair of aortic arch interruption in the neonate. Surgery 1970;67: 1006-
10. 17. Hyman MA, Berman WB, Rudolph AM, Whitman V. Dilation of the ductus arteriosus by prostaglandin E, in aortic arch abnormalities. Circulation 1976;59: 169-73. 18. Wright JS, Hicks RG, Newman DC. Deep hypothermic arrest: observations on later development in children. J THORAC CARDIOVASC SURG 1979;77:446-69. 19. Wells FC, Coghill S, Caplan HL, Lincoln C. Duration of circulatory arrest does influence the psychological development of children after cardiac operation in early life. J THORAC CARDIOVASC SURG 1983;86:823-31. 20. Williams GD, Seifen AB, Lawson NW, et al. Pulsatile perfusion versus conventional high-flow non-pulsatile perfusion for rapid core cooling and rewarming of infants for circulatory arrest in cardiac operation. J THORAC CARDlOVASC SURG 1979;78:667-77. 21. Mavroudis C. To pulse or not to pulse. Ann Thorac Surg 1978;25:259-71. 22. Yasui H, Komori M, Sese A, et al. Clinical evaluation of ~ pulsatile flow by pulsatile bypass pump for deep hypothermia and circulatory arrest in infants. J Jpn Ass Thorac Surg 1982;30:1916-23. 23. Norwood WI, Stellin GJ. Aortic atresia with interrupted aortic arch: reparative operation. J THORAC CARDIOVASC SURG 1981;81:239-44. 24. Norwood WI, Lang P, Castaneda AR, Murphy JD. Management of infants with left ventricular outflow obstruction by conduit interposition between the ventricular apex and thoracic aorta. J THORAC CARDIOVASC SURG 1983;86:771-6. 25. Damus P. Letter to the editor. Ann Thorac Surg 1975; 20:724-5. 26. Kaye MP. Anatomic correction of transposition of great arteries. Mayo Clin Proc 1975;50:638-40. 27. Stansel HC Jr. A new operation for a d-Ioop transposition of the great vessel. Ann Thorac Surg 1975;19:565-7.
THoRAc CARDIOVASC SURG
1987;93:539-45
Primary repair of interrupted aortic arch and severe aortic stenosis in neonates Two infants, aged 36 days old (Case 1) and 18 days old (Case 2) with interrupted aortic arch types B and A, respectively, and with severe aortic stenosis, were successfully operated on by use of pulsatile cardiopulmonary bypass. The great arteries were normaUy related in Case 1 and were transposed in Case 2. Repair involved the foUowing procedure: ligation of the patent ductus arteriosus, restoration of aortic continuity with an 8 nun polytetrafluoroethylene graft, placement of an internal patch to tunnel aU left ventricular blood from the left ventricle through the ventricular septal defect into the pulmonary artery in Case 1 and patch closure of the ventricular septal defect in Case 2, transection of the main pulmonary artery, anastomosis between the proximal pulmonary artery and the ascending aorta, and interposition of a valved conduit between the right ventricle and the distal pulmonary artery. The operative field could be approached easily through a median sternotomy. Postoperative cardiac catheterization revealed satisfactory anatomical and hemodynamic results in both cases.
Hisataka Yasui, M.D., Hideaki Kado, M.D., Eiichi Nakano, M.D., Kunihiro Yonenaga, M.D., Atsuo Mitani, M.D., Yukihiro Tomita, M.D., Hatsuo Iwao, M.D., Kaoru Yoshii, M.D., Yasuhiro Mizoguchi, M.D., and Hiroshi Sunagawa, M.D., Fukuoka, Japan
Interrupted aortic arch (lAA) is a rare but highly lethal anomaly in early infancy.':' Reparative operations must be used, but the surgical results are not satisfactory.5'15 Moreover, when IAA is associated with aortic stenosis, surgical management is more complex and difficult. This article presents our experience with primary repair of IAA associated with severe aortic stenosis. A new method of repair, which restores the continuity between the left ventricle and the ascending aorta, was employed in an infant with normally related great arteries. A safe method of cannulation for cardiopulmonary bypass in an infant with a small ascending aorta is presented. Case reports Between 1981 and 1985, nine patients younger than 3 months of age underwent operation for IAA at Fukuoka Children's Hospital. The first seven patients (except for
From the Divisions of Cardiovascular Surgery and Pediatrics, Fukuoka Children's Hospital Medical Center, Fukuoka, Japan. Received for publication March 12, 1986. Accepted for publication April 11, 1986. Address for reprints: Hisataka Yasui, M.D., Division of Cardiovascular Surgery, Fukuoka Children's Hospital Medical Center, 2-5-1, Tojin, Chuoku, Fukuoka 810, Japan.
one) had staged correction: In the first operation aortic continuity was restored with a 6 mm synthetic graft, with or without pulmonary artery banding, and in the second operation, 1 or 2 months later, the ventricular septal defect (VSD) was closed. There was one surgical death; the fifth patient, who had IAA type A plus VSD and underwent primary correction by use of cardiopulmonary bypass, died of a laceration of the ascending aorta at the arterial cannulation site. The last two patients had severe aortic stenosis associated with IAA and required relief of the stenosis in addition to repair of IAA. CASE L A male infant, weighing 2,970 gm at birth after an uncomplicated 40 week gestation, was noted to have tachypnea and a cardiac murmur shortly after birth. He was transferred to Fukuoka Children's Hospital at 33 days of age with a drip infusion of prostaglandin E I (PGE 1) (0.05 !J.g/ kg/min). On admission, he was mildly cyanotic. The respiratory rate was 80 breaths/min and the heart rate 160 beats/min. Systolic blood pressure was 60 mm Hg in the right arm and 65 mm Hg in the lower extremities. A Grade 2/6 systolic ejection murmur was audible along the left sternal border. Cardiac catheterization when the infant was 34 days old revealed lAA type B with an aberrant right subclavian artery, severe subvalvular and valvular aortic stenosis, a large confluent YSD, and a large patent ductus arteriosus (Fig. 1). When the infant was 36 days old (Jan. 19, 1985), median sternotomy was performed. The entire ascending aorta, the left
539
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5 40 Yasui et al.
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Fig. 1. Patient 1. Preoperative left ventriculogram shows IAA type B in the frontal view (left) and a large confluent VSD and severe valvular and subvalvular aortic stenosis (arrow) in the lateral view (right).
carotid artery, and the main pulmonary artery and its bifurcation were mobilized. The dissection was extended along the ductus arteriosus to the descending aortas, as long as the condition of the patient allowed. Cardiopulmonary bypass was initiated with a single 18 Fr. venous cannula in the right atrium. Both great arteries were cannulated (Fig. 2). A 14 gauge intravenous catheter was inserted into the aorta for perfusion and a 10 Fr. Bardic arterial cannula was placed in the main pulmonary artery. At initiation of bypass, both right and left pulmonary arteries were occluded with a silk ligature (Fig. 2, A). The patient was cooled to 22° C rectal temperature with a pump flow rate of 120 ml/kg/rnin. The arterial line to the pulmonary artery was clamped and the flow rate was decreased to 30 ml/kg/min. A partial occluding clamp was placed on the descending aorta and the previously prepared 8 mm polytetrafluoroethylene (PTFE) graft with a side arm constructed of a 6 mm PTFE graft was anastomosed to the descending aorta in an end-to-side fashion (Fig. 2, B). The clamp on the arterial line to the pulmonary artery was removed and the flow rate was increased to 70 nil/kg/min. The ascending aorta was side-clamped and the proximal end of the 8 mm PTFE graft was anastomosed to the ascending aorta (Fig. 2, C). The flow rate was decreased to 30 ml/kg/rnin, and the arterial cannula to the pulmonary artery was clamped and removed, after ligation of the patent ductus arteriosus with two silk ligatures. An effective pulsatile flow was achieved by exchanging the 10 Fr. Bardic arterial cannula for a 12 Fr. cannula, which was inserted into the side arm of the interposed PTFE graft (Fig. 2, D) and individual venous cannulation was made (Fig. 2, D). The flow rate was elevated to 170 ml/kg/min (2.5 L/m'/min) and a pulsatile bypass pump (Kontron Instrument, Model 20) was started, with a pulse rate of 100 beats/min and a driving pressure of 350 mm Hg. The patient was gradually rewarmed. The arterial line to
the ascending aorta was clamped and disconnected from the 14 gauge intravenous catheter that was connected to a cardioplegic solution line. The ascending aorta was crossclamped and cold potassium cardioplegic solution (potassium concentration 20 mEq/L) was infused (Fig. 2, D). A longitudinal incision was made in the infundibulum of the right ventricle. A large VSD involved both the perimembranous and subpulmonary regions. An elliptical Teflon patch was sewn into place to direct all left ventricular blood from the left ventricle through the VSD into the pulmonary artery (Fig. 3, A). The pulmonary artery was transected at the site of previous arterial cannulation and its proximal end was sutured end to side to the ascending aorta (Fig. 3, A). A 14 mm Hancock valved conduit was interposed between the right ventriculotomy and the distal pulmonary artery (Fig. 3, B). The aorta was unclamped after completion of the conduit anastomosis (a total of 65 minutes of anoxia). When the patient was rewarmed to 34 ° C rectal temperature, the bypass was discontinued. The postoperative course was complicated by respiratory failure and temporary complete atrioventricular block, although normal sinus rhythm returned on the twelfth postoperative day. On the ninth postoperative day, a permanent pacemaker (Biotronic NEOS-M) was implanted. However, the generator was removed on the eighteenth postoperative day because of a pacemaker pocket infection. Thirty-five days after operation, the patient was weaned from mechanical ventilation. Cardiac catheterization was performed 8 months after operation and demonstrated excellent anatomical correction and hemodynamics (Table I). CASE 2. A male infant, weighing 3472 gm, was admitted when he was 11 days old for cyanosis and congestive heart failure. He had been delivered vaginally after a 38 week gestation; birth weight was 3,300 gm.
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1AA and aortic stenosis in neonates
54 1
Fig. 2. Arterial cannulation method for lAA with patent ductus arteriosus. A, The small intravenous catheter used as an arterial cannula does not tear and narrow the small ascending aorta. The descending aorta is perfused from the main pulmonary artery through the patent ductus arteriosus. B, The previously prepared 8 mm PTFE graft, with a side arm of 6 mm PTFE graft, was anastomosed to the descending aorta in a end-to-side fashion. C, With the ascending aorta side clamped, proximal anastomosis of the PTFE graft was completed. D, After restoration of the aortic continuity, only the arterial line into the side arm of the PTFE graft is sufficient for perfusion of the whole body; the intravenous catheter into the ascending aorta can then be used for cardioplegic infusion.
On admission, he was moderately cyanotic and tachypneic. Moderate hepatomegaly was present. The femoral pulses were easily palpable. A Grade 2/6 systolic ejection murmur was audible at the left upper sternal border. Measurement of arterial blood gas showed pH 7.04, oxygen tension 53 mm Hg, and base excess -18.0. Mechanical ventilation was instituted. On the infant's fifteenth day of life, cardiac catheterization revealed IAA type A with transposed great arteries, subvalvular aortic stenosis, a large perimembranous VSD, and a large patent ductus arteriosus (Fig. 4).
When the infant was 18 days old (April 19, 1985), a midsternal splitting incision was made. Cardiopulmonary bypass was instituted in the same manner as performed in Case I. An 8 mm PTFE graft, with a previously sewn-up side arm of a 6 mm PTFE graft, was interposed between the ascending aorta and the descending aorta. Through a vertical right ventriculotomy, a large perimembranous VSD was closed by a Teflon patch. The main pulmonary artery was divided and its proximal end was anastomosed to the ascending aorta in end-to-side fashion. The aortic valve was left in
The Journal of Thoracic and Cardiovascular
542 Yasui et al.
Surgery
Fig. 3. Schematic view of repair in Patient I. A, Internal tunnel patch was sewn into place and the proximal end of the main pulmonary artery was sutured end to side to the ascending aorta. B, Completion of repair. The side arm for arterial cannulation was tied with two silk ligatures.
Fig. 4. Preoperative right ventriculogram of Patient 2 shows IAA type A, subvalvular aortic stenosis (arrow), and a perimembranous YSD.
continuity with the right ventricle. A 14 mm Hancock valved conduit was interposed between the right ventriculotomy and the distal pulmonary artery. The postoperative course was uneventful, except for temporary left phrenic nerve palsy and prolonged dependence on mechanical ventilatory support, from which he was weaned on the twenty-first postoperative day. Cardiac catheterization was performed 2 months after the operation (Fig. 5 and Table I).
Discussion The operative results of IAA obtained so far are not satisfactory and controversy exists over the optimal surgical management for the patients involved, in terms of palliative or primary reparative procedures.r" Preoperative condition of the patient, intraoperative care (including anesthesia and cardiopulmonary
Volume 93 Number 4 April 1987
fAA and aortic stenosis in neonates
543
Fig. 5. Postoperative left atriogram of Patient 2 shows smooth blood flow from the left ventricle to the proximal pulmonary artery and the ascending aorta. A small shunt (Qp/Qs = 1.2) exists.
Table I. Postoperative cardiac catheterization data Case 2
Case I Site
MPA RV RA SVC
Pressure (mm Hg) 37/15 (23)* 44/ 8 a= 6, v = 5 (3)
IVe
LA PAW FA
a= 14, v= 13 (9) 98/47 (66)
I
O2 sat. (%)
Pressure (mm Hg)
62.2 64.4 66.7 69.8 66.7
34/ 9 (17) 42/ 9 a = II, v = 12 (8)
93.0
I
O2 sat. (%) 66.7 66.7 69.8 72.8
a = 14, v = 15 (8)
91.0
83/50 (64)
95.6
Legend: MPA, Main pulmonary artery. RY, Right ventricle. RA, Right atrium. SYC, Superior venacava. IYC, Inferior vena cava. LA, Left atrium. PA W, Pulmonary artery wedge. FA, Femoral artery. 'Mean values indicated by parentheses.
bypass), surgical technique, and postoperative care all directly contribute to the surgical result. Surgical care, as well as surgical technique, has been greatly improved since the first successful palliative operation for IAA in the neonate, which was performed by Tyson, Harris, and Ngiem" in 1970. The advent of PGE 1 has dramatically changed the outlook for the neonates involved. Infusion of PGE} can significantly dilate the patent ductus arteriosus and allow diuresis and reversal of acidosis." The operation can be performed under optimal conditions, in which the patient will tolerate cardiopulmonary bypass. Some criticisms may arise in regard to palliative
interposition of the synthetic graft without cardiopulmonary bypass. In the case of a small ascending aorta, such as in IAA types Band C, there is limited room to apply a partial occluding vascular clamp, and cerebral blood flow may be compromised. Cerebral compromise may be prevented by applying a vascular clamp mainly to the left carotid artery, although this may result in a residual pressure gradient across the anastomosis. On the other hand, a small bite in the ascending aorta to maintain cerebral blood flow will allow use of only a small synthetic graft, which will become restrictive rather quickly as the patient grows.13. 14 To overcome congestive heart failure, it will be necessary to add pulmonary
5 44
The Journal of Thoracic and Cardiovascular Surgery
Yasui et al.
artery banding for the control of pulmonary arterial blood flow in most patients. However, the band may create or aggravate subaortic stenosis, as postulated by Van Praagh and associates" in 1971 and confirmed by Trusler and Freedom- in 1979. Therefore, not only in the case of subaortic stenosis, but also in the case of a conoventricular malalignment type of VSD, pulmonary artery banding would appear to be contraindicated and primary correction would be the treatment of choice. In patients with a small, thin-walled ascending aorta, there are some problems with instituting cardiopulmonary bypass. Because of the discontinuity of the aorta, the ascending aorta and the descending aorta must be perfused separately and their flow rates must be controlled. By use of cannulas of different sizes for the ascending aorta and the pulmonary artery (i.e., descending aorta), the flow rate through a Y-connected individual line is easily controlled, as in our cases. Moreover, the small cannula in the ascending aorta, a 14 gauge intravenous catheter in our cases, prevents dangerous tearing and postoperative narrowing of the thin, small aorta at the cannulation site (Fig. 2). After restoration of aortic continuity, only the arterial line to the pulmonary artery is sufficient for perfusion of the whole body during correction of an intracardiac anomaly. The intravenous catheter into the ascending aorta can then be used for cardioplegic infusion. In patients whose pulmonary artery is mobilized, as it was in our cases, an arterial cannula of optimal size can be easily placed into the newly built aortic arch through the side arm of the PTFE graft (Fig. 2, D). In most of the earlier cases of successful primary repair in infants, surface-induced profound hypothermia, combined with limited cardiopulmonary bypass and total circulatory arrest, was employed rather than conventional cardiopulmonary bypass. The time limit for circulatory arrest and the danger of brain damage compound the difficult operation. 18, 19 Recently, the cardiopulmonary bypass procedure has been progressively improved in technique, apparatus, and priming solution, which lessens its side effects. If such problems as previously mentioned are solved, a conventional cardiopulmonary bypass method will be far superior to the circulatory arrest method. A pulsatile bypass pump is a good adjunct for improvement of cardiopulmonary bypass physiologically.":" Indeed, a satisfactory result which showed an operative mortality of 3.6% and a mean duration of postoperative respiratory support of 5 days was obtained by use of high-flow cardiopulmonary bypass (2.5 Ljm 2jmin at 28° C rectal temperature) combined with a pulsatile bypass pump at Fukuoka Children's Hospital for a consecutive period of 2 years
(since January 1984) in 28 patients younger than 3 months old with complicated cardiac anomalies. In the two cases presented, a long period of postoperative respiratory support was needed. However, although the complex cardiopulmonary bypass might contribute to the patients' respirator dependency, the main causes were temporary complete atrioventricular block and subsequent pacemaker implantation through a left thoracotomy in Case 1 and temporary phrenic nerve palsy in Case 2. Severe aortic stenosis makes surgical management of IAA more complicated. To our knowledge, primary definitive repair for such combined cases has not been reported. Norwood and associatesv" reported good results with a staged operation; that is, placement of an apical-aortic conduit and pulmonary artery banding at the first stage, and closure of the VSD and removal of the pulmonary artery band at the second stage. In our experience, however, as shown in Case 1 (Fig. 3), it is possible to place an internal tunnel for subpulmonary VSD in most of the patients with normally related great arteries. This method can be employed even in patients with a diminutive ascending aorta, if the pulmonary valve is competent and the left ventricular performance is satisfactory, because the proximal pulmonary artery functions as the ascending aorta. A similar procedure was previously devised by Damus," Kaye," and Stansel" in complete transposition of the great vessels with VSD. This encouraged us to proceed. with a new approach for IAA (presented here), associated with severe aortic stenosis in patients with normally related great arteries, as well as in those with transposed great arteries. This approach seems to be simple in concept, compared with that of the apical-aortic conduit. However, it is difficult at this moment to determine which approach is superior because of insufficient long-term follow-up data. Either approach may be a valid option, depending upon the anatomy of the intracardiac anomalies.
Addendum Since submission of this article, three patients with lAA and VSD underwent primary repair by use of the same cardiopulmonary bypass technique as we have presented here. All are alive, and the mean duration of postoperative ventilatory support for them was 3 days. REFERENCES I, Roberts WC, Morrow AG, Braunwald E. Complete interruption of the aortic arch. Circulation 1962;26:3959. 2. Trusler GA, Freedom RM. Surgical approach to the managements of interruption of the aorta. In: Godman
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