Ann Thorac Surg 2002;73:76-80
© 2002 The Society of Thoracic Surgeons
Original article: cardiovascular
Total cavopulmonary connection with an extracardiac conduit: experience with 100 patients
Shigehiko Tokunaga, MD*a,
Hideaki Kado, MDa,
Yutaka Imoto, MDa,
Munetaka Masuda, MDa,
Yuichi Shiokawa, MDa,
Kouji Fukae, MDa,
Naoki Fusazaki, MDb,
Shiro Ishikawa, MDc,
Hisataka Yasui, MDd
a Department of Cardiovascular Surgery, Fukuoka, Japan
b Department of Neonate Cardiology, Fukuoka, Japan
c Department of Cardiology, Fukuoka Children’s Hospital, Fukuoka, Japan
d Department of Cardiovascular Surgery, Kyushu University, Fukuoka, Japan
Accepted for publication August 31, 2001.
* Address reprint requests to Dr Tokunaga, Department of Cardiovascular Surgery, Fukuoka Children’s Hospital, 2-5-1 Tojin-machi, Chuo-ku, Fukuoka 810-0063, Japan
e-mail: f-kodomo{at}aurora.dti.ne.jp
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Abstract
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Background. In the Fontan procedures total cavopulmonary connection with an extracardiac conduit is a concern. The potential benefits of an extracardiac conduit may be the avoidance of postoperative supraventricular arrhythmias over the long-term, hemodynamic benefits due to laminar flow, possibility of completion without anoxic arrest, and applicability to anomalous systemic or pulmonary venous return, or both anomalous systemic and pulmonary venous return. We demonstrate early to midterm results of total cavopulmonary connection with an extracardiac conduit.
Methods. Between March 1994 and February 2000, a total of 100 patients underwent total cavopulmonary connection with an extracardiac conduit. In 27 patients, who underwent a single stage total cavopulmonary connection operation, 7 were done without palliation. Seventy-three patients had undergone a bidirectional Glenn shunt before completion of the total cavopulmonary connection. We used an expanded polytetrafluoroethylene tube graft as the extracardiac conduit.
Results. Cardiopulmonary bypass time was 133.2 ± 55.2 minutes. Myocardial ischemic time was 38.5 ± 23.2 minutes in 40 patients who needed cardioplegic cardiac arrest for intracardiac procedures. Intraoperative fenestration was done in only 1 patient. There were no operative deaths. During follow-up of 37.3 months, there were 5 late deaths. When compared with the patients treated by the lateral tunnel technique in our institute, there was no significant difference in actuarial survival rate, but the event free rate of the extracardiac conduit group was significantly superior to the lateral tunnel group.
Conclusions. Total cavopulmonary connection with the extracardiac conduit produced good results in short to midterm follow-up.
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Introduction
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After Fontan and Baudet [1] reported a new operation for tricuspid atresia in 1971, various modifications of the Fontan procedure have been used for patients with functionally univentricular heart. The extracardiac conduit method is a topic of discussion pertaining to the total cavopulmonary connection (TCPC) procedure. It is said that this method has the advantages of [1] applicability to the patients with heterotaxy with systemic and pulmonary venous return and common atrioventricular valve [2], avoidance of postoperative supraventricular arrhythmia [3], possibility of completion of this procedure without cardioplegic cardiac arrest [4], and a hemodynamic advantage. This method, however, has unresolved issues, such as material and size of the graft, significance of the fenestration, necessity of the postoperative anticoagulant therapy, accommodation of the patient’s growth, and so on. We demonstrate our experience with 100 patients of TCPC with the extracardiac conduit (EC), and the short-term to midterm results of these patients.
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Patients and methods
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Between March 1994 and February 2000, a total of 100 patients underwent EC-TCPC at Fukuoka Children’s Hospital Medical Center (Fukuoka, Japan). Primary diagnoses are summarized in Table 1.
In 7 patients EC-TCPC was done without palliation. Ninety-three patients had undergone previous procedures before the completion of TCPC; bidirectional Glenn shunt was done in 73 patients, systemic-pulmonary shunt in 57, pulmonary artery plasty in 26, creation or enlargement of atrial septal defect in 23, pulmonary artery banding in 21, ligation of the main pulmonary artery in 21, atrioventricular valve plasty and replacement in 15, repair of total anomalous pulmonary venous drainage in 4, pacemaker implantation in 2, relief of systemic outflow tract obstruction in 2, and previous TCPC procedure in 2. Seven patients had undergone pulmonary artery banding, 13 with systemic-pulmonary shunt before TCPC without bidirectional Glenn shunt. In 70 patients with preliminary bidirectional Glenn shunt, 14 patients had undergone pulmonary artery banding, 38 had systemic-pulmonary shunts and 5 had hypoplastic left heart syndrome with the Norwood operation before bidirectional Glenn shunt. One patient with absent central pulmonary artery and bilateral superior vena cava had undergone bilateral classic Glenn shunt and systemic-pulmonary shunt before TCPC completion. In 2 patients EC-TCPC was performed as a redo Fontan procedure (1 patient after TCPC with a lateral tunnel technique and another patient after atrio-pulmonary connection). The indications for TCPC at our institution are an age of more than 12 months, pulmonary vascular resistance of less than 3 Wood units, mean pulmonary artery pressure less than 20 mm Hg, ejection fraction more than 30%, and pulmonary artery (PA) index (Nakata) more than 100 mm2/M2. The age of TCPC completion was 6.1 ± 4.2 years (2.1–23.3 years) and the body weight was 17.6 ± 9.9 kg (8.0–59.0 kg). In the patients who underwent previous bidirectional Glenn shunt (including bilateral classic Glenn shunt), bidirectional Glenn shunt was performed at an age of 4.4 ± 3.8 years (0.5–12.7 years) and weight of 13.8 ± 8.5 kg (8.0–55.8 kg), and the TCPC operation was completed at an age of 6.6 ± 3.4 years (2.2–23.3 years) with a mean interval of 23.7 ± 13.3 months after bidirectional Glenn shunt. All patients had undergone preoperative echocardiography and catheterization. The data for mean pulmonary arterial pressure was 10.5 ± 2.1 mm Hg before TCPC and 10.2 ± 2.7 mm Hg after TCPC; pulmonary vascular resistance was 1.7 ± 0.8 Wood units before and 1.4 ± 0.8 Wood units after TCPC; arterial oxygen saturation was 84.6% ± 3.9% before and 93.1% ± 4.0% after TCPC; ventricular end-diastolic pressure was 5.3 ± 2.7 mm Hg before and 4.4 ± 2.9 mm Hg after TCPC; pulmonary/systemic blood flow ratio was 0.9 ± 0.4 before and 1.0 ± 0.1 after TCPC; and atrioventricular valve regurgitation (grade) was 0.8 ± 0.9 before and 0.6 ± 0.6 after TCPC. Before TCPC completion, 2 patients had a mean pulmonary artery pressure equal to or more than 20 mm Hg, zero patients had a pulmonary arteriolar resistance equal to or more than 3 Wood units, and 2 patients had an ejection fraction less than 40%.
All operations were performed through a median sternotomy with a cardiopulmonary bypass and mild or moderate hypothermia. When cardiac arrest was required, cold crystalloid cardioplegic solution combined with topical cooling were used for myocardial protection. We used a nonringed expanded polytetrafluoroethylene tube graft (Gore-Tex Stretch Vascular Graft, W.L. Gore & Assoc, Flagstaff, AZ) as the extracardiac conduit to interpose between the inferior vena cava and the pulmonary artery, which was basically performed without cardioplegic cardiac arrest. Cardiac arrest was conducted only if concomitant intracardiac procedures were required. In some patients with enlargement of the atrial septal defect, ventricular fibrillation was induced. At weaning from cardiopulmonary bypass, inhalation of nitric oxide at 10 to 20 parts per milion was used to lower pulmonary vascular resistance in most of the patients. To avoid thromboembolism in the pulmonary circulation, we adopted the permanent use of warfarin sulfate postoperatively.
To compare the actuarial survival rate and event-free rate between the extracardiac conduit technique and lateral tunnel technique, the patients who underwent lateral tunnel (LT)-TCPC in our institute were investigated. The total number of the LT-TCPCs was 87 between November 1991 and November 1997 (mean age, 6.2 ± 3.9 years). Events included death, reoperation, protein-losing enteropathy, arrhythmia, and cerebral infarction.
All data are expressed as the mean ± 1 standard deviation. Actuarial survival estimate and event-free rate were calculated using the Kaplan-Meier method and compared using the log-rank test.
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Results
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The mean size of the extracardiac conduit used in this series was 17.8 ± 1.7 mm (14–22 mm), as shown in Figure 1. At the time of the completion of TCPCs, 62 patients underwent concomitant procedures (Table 2).
The cardiopulmonary bypass time was 133.2 ± 55.2 minutes (44–415 minutes). Forty patients needed cardioplegic cardiac arrest for the intracardiac procedures with the myocardial ischemic time of 38.5 ± 23.2 minutes (5–115 minutes). Most patients did not need a fenestrated Fontan procedure except 1 patient who underwent fenestration with interposition of an 8-mm nonringed expanded polytetrafluoroethylene tube graft between the extracardiac conduit and atrial wall. This fenestration was closed on the 15th postoperative day. The early postoperative outcome variables were as follows: mechanical ventilatory support was 15.1 ± 30.8 hours (1–264 hours), inotropic support was 2.1 ± 2.8 days (0–13 days), chest tube drainage was 9.6 ± 9.1 days (2–72 days), intensive care unit stay was 2.3 ± 3.5 days (1–31 days). Perioperative supraventricular arrhythmia occurred in 18 of 100 patients that were all transient (6 patients with transient supraventricular tachyarrhythmias requiring ß-blocker administration and 12 patients with sinus node dysfunction requiring temporal atrial pacing). Two patients required permanent pacemaker implantation, 1 for complete atrioventricular block before a bidirectional Glenn shunt operation, and another 1 for backup of sick sinus syndrome after ablation for preoperative paroxysmal atrial tachycardia. There were no operative deaths. A complete follow-up was done on this series. The mean follow-up period was 37.3 ± 18.1 months (maximum, 81.4 months). None of the patients experienced any new onset of supraventricular arrhythmias or protein-losing enteropathy during the follow-up period. Five patients died during the follow-up period (1 patient suddenly of unknown causes, 22 months after TCPC; 3 patients of persistent heart failure, 32 days, 20 months, and 30 months after TCPC, respectively; and 1 patient of fulminant hepatitis, 4 months after TCPC).
The actuarial survival rate in the EC-TCPC group and the LT-TCPC group is 96.7% versus 93.0% at 1 year, 93.9% versus 91.8% at 3 years, 93.9% versus 91.8% at 5 years, respectively (Fig 2).
The event free rate in the EC-TCPC group and the LT-TCPC group is 95.7% versus 87.3% at 1 year, 93.0% versus 83.8% at 3 years, and 93.0% versus 82.7% at 5 years, respectively (Fig 3). Mortality of the LT-TCPC group is 7 patients. The other events of the LT-TCPC include 7 patients with reoperation, 3 with protein-losing enteropathy, 8 with late arrhythmia, and 1 with cerebral infarction. There is no significant difference between these two groups in actuarial survival rate. However, the event-free rate of the EC-TCPC group is significantly superior to the LT-TCPC group (p = 0.037).
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Fig 2. The actuarial survival rate in the extracardiac conduit total cavopulmonary connection (EC-TCPC) group and the lateral tunnel total cavopulmonary connection (LT-TCPC) group was 96.7% versus 93.0% at 1 year, 93.9% vs 91.8% at 3 years, and 93.9% versus 91.8% at 5 years, respectively.
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Fig 3. The event free rate in the extracardiac conduit total cavopulmonary connection (EC-TCPC) group and the lateral tunnel total cavopulmonary connection (LT-TCPC) group was 95.7% versus 87.3% at 1 year, 93.0% versus 83.8% at 3 years, and 93.0% versus 82.7% at 5 years, respectively.
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Comment
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The EC-TCPC, which is a topic of discussion pertaining to the TCPC procedure [2, 3], was first described by Humes and colleagues [4] and Nawa and Teramoto [5] in 1988. We think that the EC-TCPC method is applicable to the all cases that can be the indication of the TCPC operation. In the early 30 patients of TCPC at our institute, EC-TCPC was applied to only the patients with cardiac dysfunction in which further dysfunction after cardiac arrest was expected, and to the patients with anomalous pulmonary venous return in which it was difficult to construct the intraatrial tunnel. We gradually expanded the indication of EC-TCPC. The merits of the EC-TCPC when compared with other TCPC methods are as follows: (1) no need of cardiac arrest, (2) avoidance of atriotomy, (3) no suture line in the atrium, (4) less pressure load and volume load in the atrium, and (5) laminar flow without turbulence in the conduit. These advantages of EC-TCPCs produce fewer postoperative arrhythmias and facilitate control of arrhythmias that occur [6, 7, 8, 9, 10]. Our group demonstrated that atrial natriuretic peptide is significantly less in the EC-TCPC group as compared with the LT-TCPC group [11], which demonstrates less pressure load in the atrium in the EC-TCPC group. In this study, there is no significant difference in actuarial survival rate between the EC-TCPC group and LT-TCPC group, but the event-free rate of the EC-TCPC group is superior to the LT-TCPC group, as shown in Figures 2 and 3. We have 8 patients with late onset arrhythmia and 3 with protein-losing enteropathy in the LT-TCPC group. On the other hand, we have no patients with these complications in the EC-TCPC group. We also have 2 patients with EC-TCPC conversions for postoperative arrhythmia after previous Fontan procedures in which we could control the arrhythmia by using the EC-TCPC conversion. There is an opinion that other TCPC techniques are feasible in patients with complex anatomies. We agree that LT-TCPCs can be performed on almost all patients; however, our present strategy is to perform EC-TCPCs as the first choice for the reasons previously mentioned. Actually EC-TCPCs can be done in all patients, and the operative results are stable in this series. Basically we perform TCPCs in a staged fashion [12]. However, in patients older than 2 years of age, who have an indication of TCPC (pulmonary vascular resistance < 3 Wood units, mean pulmonary artery pressure < 20 mm Hg, ejection fraction > 30%, and pulmonary artery index (Nakata) more than 100 mm2/M2), we try to do a single-stage TCPC without a bidirectional Glenn shunt.
In the selection of the size of the conduit, we try to use the largest graft that can be put in the pericardial cavity without compression of the heart and pulmonary veins. Practically, we try to use a 16-mm (diameter) conduit for patients weighing less than 10 kg, an 18-mm conduit for patients 10 to 20 kg, a 20-mm conduit for 20 to 50 kg, and a 22-mm conduit for more than 50 kg (Fig 1), which we predict to be large enough to accommodate the patient’s growth. We think we can perform EC-TCPCs without a problem in patients more than 10 months old, weighing 6 kg. Judging from the adult size of the inferior vena cava, a 16-mm graft is thought to be large enough to accommodate the patient’s growth and have a low risk of reoperation; accordingly, an 18-mm graft is thought to be no problem. In case of reoperation for stenotic graft, redo operations can be performed under a beating heart or may be done off-pump [10, 13]. However, further follow-up is necessary for the major concern of outgrowing the conduit or developing late conduit stenosis because the follow-up period is rather short in this study.
Contrary to most other contemporary series in which the fenestration is used routinely [14, 15], we principally do not use fenestration because acute elevation of pulmonary resistance can be treated with nitric oxide inhalation. Practically, we observe the postcardiopulmonary bypass course for 2 hours with nitric oxide inhalation, and temporal fenestration is necessary only in the patient with poor response of nitric oxide; the rate of fenestration is about 1%. The EC-TCPC has an advantage that fenestration can be easily made off-pump. Closure of fenestration also can be done without cardiopulmonary bypass [10]. With this strategy, 90% of single ventricle patients (which can be the indication of TCPC) reach TCPC, and we emphasize that we had no operative mortality despite TCPC being performed without fenestration in 99 of 100 patients. Our good results without fenestration may be attributed to the beneficial effects of the extracardiac conduit and our good patient selection.
In this study, the mean age at the time of both EC-TCPC and bidirectional Glenn shunt are actually old by the current world standard. Recent TCPC patients in the last 3 years are performed at the age of 3 to 4 years old. In our newest strategy, we think that bidirectional Glenn shunt can be done at an age of more than 6 months, and TCPC at an age of more than 1 year.
Hypoplastic left heart syndrome patients with EC-TCPC were rare at our institute because the number of survival patients after Norwood operations was small before 1995. But EC-TCPC was performed in 15 hypoplastic left heart syndrome patients in our newest data, and all of the patients survived. Hypoplastic left heart syndrome patients after Norwood operations may be a good indication for EC-TCPCs because there are many patients with cardiac dysfunction and difficult aortic cross clamps. Because many patients with hypoplastic left heart syndrome are very young (1 to 2 years old), it may be pointed out that EC-TCPC is a disadvantage from the standpoint of the patient’s growth. However, we think that more than a 16-mm graft can be applicable if the patient is more than 6 kg, and that good long-term results can be expected.
To prevent thromboembolism and late stenosis of the EC-TCPC, we adopt permanent use of anticoagulation with warfarin sulfate. Cromme-Dijkhuis and colleagues [16] suggested that there are coagulation factor abnormalities even in patients with an apparently good clinical condition after the Fontan procedure. Jahangiri and colleagues [17] demonstrated that 16% of the patients after the Fontan procedure showed thromboembolism. They recommend that all patients undergoing Fontan procedures require long-term anticoagulation therapy. Our group also suggests that Fontan patients have a potential thromboembolic risk owing to the deficiency of thrombomodulin in the endothelial cell surface of the venous vessels, and it is possible that the systemic venous hypertension in Fontan circulation may activate the endothelial cell of the venous vessels leading to the down-regulation of thrombomodulin [18]. For the reasons previously mentioned, we currently recommend permanent use of warfarin sulfate postoperatively to avoid thromboembolism in the pulmonary circulation. Further follow-up is necessary to confirm the benefit of anticoagulation therapy pertaining to incidence of thromboembolism.
In conclusion, we demonstrated 100 patients of EC-TCPCs whose clinical results were satisfactory. Most of these procedures were performed without fenestration of the Fontan circulation. This study demonstrated significant improvements in mortality and morbidly compared with a previous study for LT-TCPCs [19]. However, further follow-up is necessary for the major concern of outgrowing the conduit or developing late conduit stenosis and for the effect of the anticoagulation therapy.
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Acknowledgments
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We express our gratitude to Mr Philip Harding (Planet English, Fukuoka, Japan) and Ms Zoni Madison (Department of Thoracic and Cardiovascular Surgery, The Cleveland Clinic Foundation, Cleveland, OH) for the English revision of this article. We also thank Dr Toshihide Nakano (Department of Cardiovascular Surgery, Fukuoka Children’s Hospital, Fukuoka, Japan) for the comment about statistical analysis.
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References
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Abstract
Introduction
