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Ann Thorac Surg 2001;71:71-76
© 2001 The Society of Thoracic Surgeons
a Departments of Cardiovascular and Thoracic Surgery and Congenital Heart Disease, German Heart Institute Berlin, Berlin, Germany
Accepted for publication May 14, 2000.
Address reprint requests to Dr Alexi-Meskishvili, Deutsches Herzzentrum Berlin, Augustenburger Platz 1, 13353 Berlin, Germany
e-mail: alexi{at}dhzb.de
| Abstract |
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Methods. Thirty-three patients underwent ECFO at median age 4.1 years. Normothermic perfusion with the heart beating was used in 24 patients and cardioplegia in 7. Fenestration was not performed in the last 16 patients who underwent surgery without cardioplegia.
Results. The hospital mortality was 6% (2 patients). Necessity or duration of inotropic support, duration of mechanical ventilation, intensive care unit and hospital stay, and incidence of prolonged pleural effusions of patients operated on without cardioplegia were shorter and the rate of complications in these patients was lower than in patients who underwent cardioplegia.
Conclusions. Our preliminary experience shows that ECFO can be performed in many patients with normothermic cardiopulmonary bypass and without cardioplegia and fenestration. Avoidance of cardioplegia seems to decrease postoperative morbidity. Incidence of early postoperative arrhythmias is low. Despite encouraging early results, longer follow-up is necessary to prove the real advantages of ECFO.
| Introduction |
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| Patients and methods |
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Total pulmonary artery (Nakata) index (TPAI) [9] and total lower lobe index (TLLI) [10] were calculated in all patients to evaluate the adequacy of the central and peripheral pulmonary arteries. Normal values of TLLI (120 ± 30 mm2/m2) were obtained from pulmonary angiograms of the 20 children without significant cardiovascular diseases. A low TPAI (less than 200 mm2/m2) was observed in 6 patients, but in all the TLLI was normal (Fig 1, Table 3). Three patients had a mean pulmonary arterial pressure of more than 15 mm Hg. Severe atrioventricular valve incompetence was observed in 3 patients.
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Afterwards, the inferior vena cava was clamped at the cava-atrial junction and divided from the right atrium, and the latter was then closed with a running suture over the clamp. Using continuous monofilament sutures, a polytetrafluroethylene (PTFE) graft of maximum possible diameter was anastomosed end-to-side to the inferior aspect of the right pulmonary artery. The proximal end of the PTFE graft was connected end-to-end to the transected inferior vena cava and included in the anastomosis a short rim of the excised right atrial wall to make the anastomosis larger than the inferior vena cava caliber. For most children the conduit was 20 to 22 mm in diameter and it was 24 mm in adults.
In the first 17 patients, fenestration (4 to 5 mm) between the medial wall of the PTFE graft and the lateral aspect of the right atrium was routinely created after termination of CPB. In 6 of them a short PTFE graft with a diameter of 4 to 5 mm was used to create fenestration and in the other 11 patients direct anastomoses between graft and adjunct atrial wall were performed. In the last 16 patients fenestration was not performed because of the low atrial filling pressures and acceptable hemodynamic status after CPB. An additional 78 concomitant procedures during ECFO were necessary in the 28 patients (Table 4). In 3 patients reconstruction of severely incompetent atrioventricular valves was performed: tricuspid annuloplasty in 1, approximation of common anterior and posterior leaflets and cleft closure in 1, and tricuspid annuloplasty and mitral cleft closure in 1.
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Statistical analysis
Statistical analysis was performed using the Mann-Whitney U test with separate variance and
2 tests. Variables were analyzed using multivariate analysis SPSS for Windows 8.0 (SPSS, Inc, Chicago, IL) to determine the risk factors for postoperative complications. The difference was considered statistically significant when the p value was 0.05 or less.
| Results |
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Postoperative complications and morbidity
Severe postoperative complications (low cardiac output, myocardial dysfunction, acute renal failure, malignant dysrhythmias) were observed in 5 patients, 2 of them mentioned above died early postoperatively. Other complications were prolonged (more than 12 days) pleural effusions (n = 6), chylothorax (n = 5), and transient supraventricular tachyarrhythmias (n = 3). Two patients necessitated prolonged respiratory support: a 37-year-old patient with a nonbalanced double outlet right ventricle developed myocardial dysfunction and acute renal failure that required catecholamine support and venovenous continuous hemodialysis. Because of severe tracheal bleeding 10 days after the operation, an emergency tracheostomy was performed and mechanical ventilatory support was necessary for 24 days. The other patients, a 4.6-year-old child with a left atrioventricular valve atresia, preoperative right phrenic nerve palsy, and multiple aortopulmonary collaterals and high pulmonary artery pressure (18 mm Hg) developed respiratory insufficiency and arterial oxygen desaturation that necessitated positive pressure ventilation with nitric oxide. Despite plication of the diaphragm 2 weeks after ECFO and transcatheter closure of multiple MAPCAs, all attempts at extubation were unsuccessful and a tracheotomy was performed 1.5 months after surgery. Afterwards, the volume of mechanical ventilation was continuously decreased and he was discharged from our institution on the 67th postoperative day with a tracheostomy. Exploration for bleeding was necessary in 2 patients.
All patients without complications were extubated within the first 24 hours postoperatively (median 9, range 4 to 24). The median hospital stay after an uncomplicated postoperative period (n = 17) was 11 days (range 7 to 22) and 38 days (range 19 to 67) in patients with complications (n = 16).
The necessity or duration of inotropic support, duration of mechanical ventilation, stay in the intensive care unit (ICU) and hospital stay, incidence of prolonged pleural effusions (> 7 days), in patients operated on without cardioplegia were shorter and the rate of complications in these patients was lower than in patients operated on with cardioplegia (Table 5).
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Arterial oxygen saturation in patients with fenestration before discharge was 90% ± 2% (median 93%) when compared with patients without fenestration (96% ± 2%, median 97%) p = 0.004.
Early postoperative catheter interventions
In 1 patient a dilated ascending aorta caused compression of the main left pulmonary artery and mild arterial desaturation. After stenting and dilatation of the subaortic part of the left pulmonary artery, the arterial saturation was normalized. One 3-year-old patient developed severe arterial desaturation postoperatively. After transcatheter closure of the fenestration he was extubated on the second postoperative day. In 1 patient with prolonged (more than 12 days) pleural effusions, coil occlusion of the major aortopulmonary collaterals was followed by an abrupt disappearance of the pleural effusion.
Early postoperative arrhythmias
Sinus rhythm preoperatively was recorded in 29 patients. One patient with multiple risk factors developed complete AV dissociation after ECFO and died 12 hours after operation. Two patients had an ectopic atrial rhythm before and after surgery. Five patients had a transient sinus node dysfunction early postoperatively and 2 patients with preoperative sinus rhythm were in ectopic atrial rhythm late postoperatively. Supraventricular tachyarrhythmias observed in the intensive care unit were successfully treated with medications in 3 patients. In 1 patient with preoperative complete AV block, a previously implanted pacemaker was intraoperatively replaced. Of 29 patients with preoperative sinus rhythm 25 (86.2%) remained in sinus rhythm on discharge (Table 6).
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Follow-up catheterization
Fifteen patients underwent follow-up cardiac catheterization and angiography (median 8 months, range 2 to 18). Mean pulmonary artery pressure during catheterization was 12 mm Hg (median) with a range of 8 to 20 mm Hg, and median arterial oxygen saturation was 95% (range 91% to 97%). External conduit shape changes were not observed. Spontaneous closure of fenestration was found in 4 patients. In 1 patient a fenestration was closed with the umbrella device. In 1 patient a fistula between the left coronary artery and the right ventricle and in another patient a large venous collateral between the superior vena cava and the left pulmonary artery were closed with coils.
One 3.5-year-old patient developed protein-losing enteropathy 3 months after surgery. Cardiac catheterization revealed a partial thrombosis and stenosis of a significantly oversized conduit (more than 2.0 times greater than the inferior vena cava diameter). She underwent conduit replacement with a 16-mm aortic homograft at 4 years of age. She is now free of symptoms. In a 27-year-old patient with a left-sided azygos vein, which served as the main channel for the Fontan circulation, a partial thrombosis of the 24-mm conduit that connected the hepatic veins with the right pulmonary artery, without a pressure gradient, was found.
Late reoperations
One year after surgery, a 3.5-year-old patient with protein-losing enteropathy underwent successful replacement of a thrombosed and stenotic conduit with a 16-mm aortic homograft using partial CPB, and the enteropathy symptoms disappeared.
No late deaths were observed during the follow-up period (median follow-up 16.5 months; range 3 months to 4.0 years) in the 31 surviving patients.
| Comment |
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Preoperative evaluation of the pulmonary arterial tree is of major importance in the selection of candidates for ECFO. Some do not recommend the performance of the Fontan operation when the TPAI is below 170 to 180 mm2/m2 [11], although the lowest PAI that precludes a successful Fontan operation is not known [12]. We as well as Reddy and associates [10] found that the TLLI is more informative than the TPAI for the selection of candidates for a Fontan operation, because TLLI is not influenced by congenital or iatrogenic central pulmonary artery deformations. In 6 patients with a low TPAI (under 200 mm2/m2, lowest 138 mm2/m2), the presence of a normal total lower lobe index (>100 mm2/m2) enabled us to successfully perform ECFO combined with the patch augumentation of the central pulmonary arteries in 4 of them.
Because of the high incidence of obstruction of the dacron conduits as a result of the development of a fibrous peel on the internal surface, we used PTFE grafts. Generally, all conduits for ECFO have common disadvantages, such as a lack of growth potential, thrombogenicity, and an absence of a transvenous approach for pacemakers [13]. Use of a pericardial tube or an aortic homograft may be another option [5, 6].
The mean diameter of the intrapericardial part of the inferior vena cava in an adult is around 20 mm [14, 15]. Thus a PTFE graft with a diameter of 18 to 20 mm implanted in children between 2 and 4 years of age, when the diameter of the cardiac end of the IVC approaches 70% to 80% of the adult diameter [14, 15], seems to be appropriate for life-long function, although significant conduit oversizing should be avoided because it can lead to unfavorable Fontan hemodynamics [16]. We now prefer implantation of the extracardiac conduits that are larger than the actual diameter of the inferior vena cava, as measured angiographically, by no more than 20%. Partial conduit thrombosis was observed in 2 patients with oversized conduits. One of them developed conduit stenosis and protein-losing enteropathy, which was successfully treated with conduit replacement. Thrombus formation occurs in as many as 20% of patients after all types of Fontan operation [1, 17, 18], therefore most groups recommend anticoagulation treatment after ECFO [4, 7, 18, 19]. Our anticoagulation regimen now includes a combination of warfarin and aspirin over the first 6 months after surgery in older children and adults to target the International Normalized Ratio (INR) of between 2 and 3, and aspirin combined with antiplatelet drugs in patients under 10 years of age.
After ECFO, Amodeo and colleagues [8] reported conduit diameter reduction of up to 20% because of development of fibrous peel but the type of conduit used was not mentioned. Such changes were not observed in 15 of our patients who underwent postoperative angiography.
It has been reported that after ECFO there has been a decreased use for fenestration [2, 6, 20]. The nonuse of fenestration theoretically prevents potential paradoxic thromboembolic complications [2, 18]. If direct anastomoses between conduit and atrium is performed, sizing of fenestration is technically difficult in patients with severe atrial hypertrophy, and now we prefer interposition of a short (4 to 5 mm) PTFE graft between the conduit and the atrial wall if fenestration is necessary. Our current indications for fenestration are a high transpulmonary gradient (more than 10 mm Hg) and a high Fontan pressure (higher than 18 to 20 mm Hg) that persists for more than 30 minutes after termination of CPB. Because of acceptable hemodynamic after CPB, fenestration was not necessary in the last 16 patients operated on without cardioplegia. If the fenestration is still open at follow-up cardiac catheterization test, occlusion of the fenestration by balloon is performed. In the absence of a negative reaction (stable cardiac output, no increase of Fontan and pulmonary arterial pressures and absence of residual pulmonary branch stenosis), the fenestration is closed with an umbrella device [21].
After ECFO, a lower incidence of atrial arrhythmias can be expected because of the absence of multiple atrial suture lines [2, 5]. Late atrial dysrhythmias were observed in less then 7% of a large group of the patients after ECFO [2], although Shirai and coworkers [18] observed a 44% incidence of sinus node dysfunction after ECFO when they used 24-hour Holter monitoring. In our series 86.2% of the patients with sinus rhythm preoperatively remained in sinus rhythm on discharge and 89.6% maintained a sinus rhythm during the follow-up period.
Serous pleural effusions were reported in up to 33% of the patients after ECFO [2, 4, 8]. A higher incidence of prolonged pleural effusions (> 7 days) was observed in our patients who underwent surgery with cardioplegia (Table 5). Significant aortopulmonary collaterals may contribute to prolonged pleural effusions and can be a potential source of morbidity [22]. Postoperative coil occlusion of MAPCAs in 1 of our patients was followed by a dramatic cessation of pleural drainage and can be recommended preoperatively.
In conclusion, our preliminary experience shows that ECFO can be performed in many patients with normothermic CPB and without cardioplegia and fenestration. Avoidance of cardioplegia seems to decrease postoperative morbidity. The incidence of early postoperative arrhythmias is low. Despite some encouraging early results, longer follow-up is necessary to prove the real advantages of extracardiac Fontan operation.
| Addendum |
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| Acknowledgments |
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| References |
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