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Ann Thorac Surg 2009;88:1527-1533. doi:10.1016/j.athoracsur.2009.06.036
© 2009 The Society of Thoracic Surgeons
Original Articles: Pediatric Cardiac
Current Surgical Management of Ascending Aortic Aneurysm in Children and Young Adults
Masamichi Ono, MDa,*,
Heidi Goerler, MDa,
Dietmar Boethig, MDb,
Mechthild Westhoff-Bleck, MDc,
Thomas Breymann, MDa
a Division of Cardiothoracic, Transplantation, and Vascular Surgery, Hannover Medical School, Hannover, Germany
b Department of Pediatric Cardiology and Intensive Care Medicine, Hannover Medical School, Hannover, Germany
c Department of Cardiology and Angiology, Hannover Medical School, Hannover, Germany
Accepted for publication June 16, 2009.
* Address correspondence to Dr Ono, Division of Cardiothoracic, Transplantation, and Vascular Surgery, Hannover Medical School, Carl-Neuberg-Str 1, Hannover, 30625, Germany (Email: ono.masamichi{at}mh-hannover.de).
| PEDIATRIC CARDIAC SURGERY:
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Abstract
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Background: The low incidence of aortic aneurysm among children and young adults limits information about etiology, surgical indications, procedures of choice, and operative results.
Methods: From 2003 to 2008, 35 patients aged 7 to 35 years (mean 21) underwent replacement of the ascending aorta for 19 ascending aortic aneurysms and 16 aortic root aneurysms. Underlying diseases included 10 congenital aortic stenoses, 10 bicuspid aortic valves, 8 congenital heart diseases, 6 Marfan syndromes, and 1 aortitis.
Results: Indications for surgery were maximal diameter of 200% of normal for isolated aneurysms, and 160% of normal in case of associated aortic valve dysfunction or symptoms. Operative procedures included 27 ascending aortic replacements with or without aortic valve replacement (including 22 conduits) and 8 valve-sparing operations, performed in 6 patients with Marfan syndrome and 2 with congenital heart diseases. There was 1 in-hospital death. Thirty-four patients survived the operation and are in New York Heart Association functional class II or less at a maximum of 5 years of follow-up. All patients are free from reoperation, but 1 patient had a thromboembolic event. Aortic valve function is good in all 8 patients after the valve-sparing operation.
Conclusions: Ascending aortic aneurysm in children and young adults was surgically treated with excellent midterm outcome. A diameter of 200% of normal was the indication for surgery; however, in case of associated lesions, smaller diameters should be considered for surgery. Conduit implantation is the gold standard. Valve-sparing operation can be performed in selected patients with encouraging results.
The incidence of ascending aortic aneurysms in children and young adults is low. These aneurysms are usually encountered in patients with underlying connective tissue diseases (for example, Marfan, Ehlers-Danlos, and Turner syndromes) [1, 2], or in patients with bicuspid aortic valves [3]. Isolated forms are only rarely reported [4]. Dilation of the ascending aorta or the aortic root has also been described in patients after surgery for congenital heart disease (CHD), such as congenital aortic stenosis [5], tetralogy of Fallot [6, 7] and truncus arteriosus [8, 9]. These aneurysms may lead to rupture, dissection, or valve insufficiency. Therefore, prophylactic root replacement might be indicated. However, so far, there are only few reports on the surgical therapy of ascending aortic aneurysms in children and adolescents.
The purpose of this study was the clarification of surgical indications, choice of the appropriate procedure, and midterm results, by reviewing our recent experience with 35 children and young adults who have undergone replacement of the ascending aorta.
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Patients and Methods
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Patients
This retrospective study was undertaken with approval of the Ethics Committee, and a waiver for consent was obtained from the Ethics Committee. Between August 2003 and August 2008, 35 patients (14 children and 21 young adults) with ascending aortic aneurysms were referred to our department from a pediatric or GUCH (Grown Up Congenital Heart disease) cardiologist. Underlying diseases of the patients are summarized in Table 1. The age of the patients ranged from 7 to 35 years (mean 21.0 ± 7.5), and 32 of them were male (Table 2). Twenty patients had surgical or interventional history for CHD (Table 3). Previous interventional procedures were balloon dilatation of aortic valves (patient 4), and interventional closure of a patent ductus arteriosus (patient 20), The remaining 18 patients underwent a total of 35 cardiac operations: 8 open aortic valvotomies, 7 right ventricular outflow tract reconstructions (RVOTR), 5 aortic valve replacements (1 concomitant RVOTR), 5 repairs of the coarctation of the aorta, 3 repairs of tetralogy of Fallot and its variants, 2 Ross procedures, 2 repairs of truncus arteriosus, 1 aortic valve repair with concomitant RVOTR, 1 arterial switch operation, 1 Mustard procedure, 1 Blalock-Tausig shunt, and 1 pulmonary artery banding. As for the 5 patients who underwent previous aortic valve replacement (8, 9, 10, 11, and 12 years earlier, respectively), dilation of ascending aorta was not prevalent at that time.
Preoperative Assessment and Indication for Surgery
All patients were followed by our institute or an associated outpatient clinic. They had been referred to our unit with the diagnosis of ascending aortic aneurysm. Computed tomography and echocardiography were standard diagnostic tools to evaluate the aortic diameter and aortic valve function. Cardiac catheterization and selective coronary angiography were performed in all 21 adult patients. Six of 14 children underwent cardiac catheterization. Magnetic resonance imaging was done in selected patients.
Nineteen of 35 patients presented with supracoronary ascending aortic aneurysm, and 16 patients with aortic root aneurysm (Table 4). After interventional patent ductus arteriosus closure, 1 patient (patient 20) had additional aortic arch aneurysm with ascending aortic aneurysm. The maximum diameter of aortic aneurysms ranged between 40 and 60 mm (mean 47.5 ± 5.9 mm) with an index (percent of normal values [10]) between 129% and 250% (mean 178.7% ± 29.2%), respectively (Table 2). Fourteen patients demonstrated moderate to severe aortic insufficiency, and 3 patients showed moderate to severe aortic stenosis. Eight patients were symptomatic.
Operative indications are summarized in Table 5. Indications for surgery were isolated aneurysms in 18 patients. Among them, 4 patients required concomitant RVOTR due to severe RVOT graft insufficiency (3 patients with tetralogy of Fallot and 1 patient with truncus arteriosus). In the remaining 17 patients, indications for operation were combined aortic aneurysms and significant aortic insufficiency (14 patients) or aortic stenosis (3 patients). According to our institutional policy, aortic replacement is indicated if the aortic diameter reaches 4.5 cm. Severe aortic valve dysfunction associated with an aortic diameter of 4.0 cm or more is also considered an indication for aortic replacement. In addition, clinical symptoms were taken into consideration. Progression of their aneurysms was documented in 11 patients including 5 with Marfan syndrome. In children, an aortic diameter of more than 200% of normal was considered an indication for surgery. The maximum diameter and the maximum index were significantly different between patients with and without associated aortic valve dysfunction (44.7 ± 4.7 versus 50.2 ± 5.7 mm [p = 0.004] and 164.1 ± 24.0 versus 192.6 ± 27.2% [p = 0.002]; Table 6).
Surgical Technique
Aortic root replacement with valved conduits (Bentall operation), valve-sparing operation, and supracoronary ascending aortic replacement with and without concomitant aortic valve replacement were performed. The operative techniques have been described previously [11-14]. In case of valved conduit implantation, the conduit is anchored in the aortic annulus using pledgetted 2-0 horizontal mattress sutures with the pledgets put in the subannular position. Valve-sparing operations are performed using a 28-mm Dacron (C. R. Bard, Haverhill, PA) prosthesis as standard size. We occasionally use a 26- or 30-mm graft according to the size of the aortic annulus.
Follow-Up
Routine follow-up was performed by transthoracic echocardiography at 3, 6, and 12 months, and at yearly intervals thereafter. Valve morphology as well as systolic and diastolic function was assessed in accordance with published criteria. Adverse events such as infections, thromboembolism, and bleeding were recorded as required by the guidelines of the American Association for Thoracic Surgery/Society of Thoracic Surgeons [15]. The cumulative follow-up period was 739 months, with a minimum 3 months and a maximum of 63 months (mean, 21).
Statistical Analysis
Continuous variables are expressed as mean ± SD. Data analysis was performed with SPSS 16.0 for Windows (SPSS Inc, Chicago, IL). Kaplan-Meier analysis was used for the evaluation of time-related variables. The Mann-Whitney U test was used for variables that were not normally distributed. A Student t test or analysis of variance test was used to compare normally distributed variables. A value of p less than 0.05 was accepted as statistically significant.
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Results
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Perioperative Results
In all patients, standard median sternotomy and cardiopulmonary bypass (CPB) were used. In 5 patients, CPB was initially established by cannulation of the femoral vessels, as the dilated ascending aorta was directly adhering to the sternum after the previous operation. In the remaining 30 patients, CPB was begun after initial sternotomy. Aortic root replacement with valved conduits (Bentall operation) was performed in 22 patients, valve-sparing operation was performed in 8 patients, and supracoronary ascending aortic replacement was performed in 5 patients including concomitant aortic valve replacement in 2 patients (Table 7). In 20 patients with congenital aortic stenosis or bicuspid aortic valves, conduit replacement or supracoronary graft replacement of the ascending aorta was the procedure of choice. No valve-sparing operation was done in this cohort. On the contrary, all 6 patients with Marfan syndrome received aortic valve-sparing operation. Among 7 patients with complex CHD, 2 patients after tetralogy of Fallot repair and Mustard procedure for the transposition of the great arteries underwent valve-sparing operation. Both patients had aortic root dilation after corrective operation, whereas aortic valves were well preserved. The remaining 5 patients received conduit replacement. In this cohort with complex CHD, concomitant procedures included 6 subsequent RVOTR, 1 residual ventricular septal defect closure, and 1 right pulmonary artery reconstruction. One patient, who had ascending and proximal arch aneurysm after interventional patent ductus arteriosus closure, underwent graft replacement of the ascending and proximal arch. One patient with aortitis associated with Wiskott-Aldrich syndrome, a rare disorder of the immune system, had inflammatory dilation of the ascending aorta. He underwent biological conduit implantation, as described before [16]. In all patients, termination of CPB was uneventful without any mechanical support. Mean CPB and aortic cross-clamp times were 187 ± 97 minutes and 92 ± 27 minutes, respectively.
There was only 1 in-hospital death. This patient had four previous operations with the diagnosis of truncus arteriosus. Rethoracotomy and dissection turned out to be extremely demanding because of severe adhesions. Bleeding from lung tissue occurred at the site of dissection. His respiratory function worsened postoperatively, and he died of respiratory failure on postoperative day 16. All other 34 patients survived the procedure. There was no perioperative stroke, arrhythmia, or myocardial infarction. Pericardial tamponade requiring rethoracotomy developed in 3 patients. Two patients had an atrioventricular block grade III and needed pacemaker implantation. Two patients had wound infections that required antibiotic therapy. The other patient had renal dysfunction and received diuretic therapy until he was discharged on postoperative day 19. In the remaining 26 patients, the postoperative course was uneventful. The length of intensive care unit stay was 3.3 ± 5.0 days and length of hospital stay was 11.8 ± 5.4 days.
Follow-Up
All 34 hospital survivors were alive during follow-up and in New York Heart Association functional class II or less. One patient with Marfan syndrome who received a valve-sparing operation had a lung embolism 8 months postoperatively. This patient had a familial history of lung embolism and hereditary thrombophilia (factor V Leiden). Another patient had intermittent atrioventricular block and underwent pacemaker implantation 3 months postoperatively. There were no bleeding events, nor was there any need for reoperation. In the 8 patients after valve-sparing operation, valve function was routinely evaluated. Native aortic valve insufficiency was minimal in 6 patients and mild in 2 patients at the latest examination. Actuarial survival of all patients was 97.1% at 5 years. Freedom from reoperation was 100% at 5 years.
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Comment
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This study demonstrated our recent results with 35 children and young adults with ascending aortic aneurysms undergoing surgical replacement of the ascending aorta. As for underlying diseases, previous studies have shown that the ascending aortic aneurysms in children were mainly associated with Marfan syndrome [1, 2]. However, in our patients, aortic aneurysms were associated with congenital aortic stenosis, bicuspid aortic valves, and CHD as well as Marfan syndrome. There was a tendency toward the development of ascending aortic aneurysms in patients with congenital aortic stenosis and bicuspid aortic valves. In contrast, the patients with Marfan syndrome and CHD had aortic root aneurysms. According to recent publications, an abnormal histology and genetic alteration of the ascending aorta were found to be associated with bicuspid aortic valves [3]. Similar to Marfan syndrome, the aortic wall showed typical histologic findings including medial degeneration, increased matrix metalloproteinase activity, and decreased fibrillin-1 expression. Concerning sex association, ascending aortic aneurysms developed more frequently in male than in female patients, comparable to adult patients. Accordingly, our patients were predominantly male (85%).
As for the indication for surgery, there is little information about the risk of aortic rupture or dissection in children or young adults. No clear cut-off point concerning the diameter of aneurysms exists. Carrel and colleagues [2] reported 26 patients younger than 18 years (mean, 10 ± 4.8) whose mean diameter of aortic aneurysm was 41 ± 13 mm (range, 34 to 71 mm). However, they did not provide any body-size related index. For our patients, we calculated an index by relating the size of the aortic aneurysm to the normal diameter of the ascending aorta, which Rose and coworkers [10] reported previously. By this calculation, an aortic diameter of 200% of normal diameter was considered the cut-off diameter for surgical intervention for isolated aneurysms. An index of 160% of normal was considered the cut-off point for patients with associated severe aortic valve dysfunction or clinical symptoms.
Concerning the surgical procedures, conduit replacement and the valve-sparing operation are our currently applied treatment. Homograft replacement is not an option because of its disappointing durability. In this series, we performed separate replacement of the ascending aorta and aortic valve in 2 patients during the initial study period; however, we currently prefer conduit replacement to this procedure. In this study, all of 20 patients with congenital aortic stenosis and bicuspid aortic valves underwent conduit replacement or separate ascending and aortic valve replacement. No patient was indicated for valve-sparing operation, because the nature of aortic valves was not thought to be suitable for aortic valve reimplantation. This subgroup included 2 patients who had undergone a Ross procedure at age 14 and 15 years and showed progressive dilation of the autograft 8 and 10 years postoperatively. Autograft dilation has been well documented after Ross operation [17, 18], and the valve-sparing operation has been performed in selected patients [18]. However, in the patients of our study, cusp deformities as well as root dilation were recognized, and mechanical conduit replacement was done in both patients.
The Ross operation might be an alternative for patients with combined ascending aneurysms and severe aortic valve dysfunction. This procedure had been performed worldwide on neonates to adult patients, but recently, the indication of this procedure has been reconsidered because of the late problems of the autograft and the durability of the conduit in the pulmonary position. Conversely, encouraging results with mechanical valve replacement have been shown even for children. Our current indication for Ross operation has been limited to small children.
On the contrary, all of the 6 patients with Marfan syndrome underwent valve-sparing operation. According to our experience and other reports [19], aortic root aneurysm associated with Marfan syndrome is a good indication for an aortic valve-sparing operation because the aortic valves do not have relevant structural defect or severe cusp prolapse. Previously published studies by our group and other groups support these results, that a valve-sparing operation for Marfan syndrome is an appropriate procedure of choice for children [19] as well as for adult patients [20, 21].
Our study demonstrates the need for surgical management of ascending aortic or aortic root dilation late after the repair of complex CHD with great artery anomalies such as tetralogy of Fallot [5, 6], truncus arteriosus [7, 8] and transposition of the great arteries [14]. In these patients, histologic anomalies of the great arteries are documented [7], and there is an intrinsic potential for the late development of ascending aortic aneurysms. Also, little information can be obtained about incidence, operative indication, and surgical procedure for ascending aneurysms with complex CHD. It seems that the pathophysiology of these patients is complicated because of the complexity of their underlying diseases and their previous operations. The operative indication and the procedure should be considered case by case. From our experience with 7 patients, 2 patients after repair of tetralogy of Fallot and Mustard operation who had root aneurysm late after corrective procedures, underwent valve-sparing operation. In these patients, no additional reoperation was done after their corrective surgery, and the patients' own aortic valves were intact. The remaining 5 patients underwent mechanical valve conduit replacement, and 4 of them changed their RVOT conduits concomitantly. Timing of surgery should be considered for both aortic and pulmonary lesions, and reoperation itself after repeated surgeries (total 17 times for 5 patients) had considerable risks for them. The main reason for the choice of mechanical conduit was to minimize the risk for further reoperation.
Concerning the indication for aortic valve-sparing operation, we have extended the indication from ascending aortic aneurysm [22] to Marfan syndrome [19] and acute aortic dissection type A [23]. We previously reported a favorable durability of the native aortic valve, and also demonstrated excellent hemodynamics of this technique after a decade [13, 24]. Some of the procedure was done as reoperation [14, 25]. However, indication for this procedure should be strictly selected in children and young adults because their lifespan is much longer than for other populations. Not only the nature of the aortic valves, but also the risk of reoperation and the pathology of coexistent RVOT lesions should be additionally taken into account [26]. Valve-sparing operation for bicuspid aortic valves is another challenging field. The indication for valve-sparing operation in patients with bicuspid aortic valves is still discussed controversially. The long-term durability of bicuspid aortic valve is still unknown. Aicher and associates [27] showed results of valve-sparing operations for patients with bicuspid aortic valves that were comparable to those for patients with tricuspid valves [27], whereas the other reports demonstrated the impaired durability of bicuspid aortic valves after repair [28, 29]. As long-term durability of reimplanted bicuspid valves is currently unknown, we perform composite graft replacement in patients with congenital bicuspid valves. Exceptionally, we performed one valve-sparing operation in a 9-year-old Marfan patient with bicuspid valves because her aortic valves were intact.
As for the 5 patients who had established CPB before sternotomy, we canulated into the femoral vessels. Subclavian artery canulation is an alternative and has an advantage of keeping antegrade flow into the aorta. However, our young adult patients did not have any cerebral complications in spite of retrograde perfusion of the aorta. Furthermore, femoral access is simple and has cosmetic advantages for young patients.
In conclusion, our results demonstrated that operative indication is 200% of normal diameter for isolated aneurysms. If aortic valve dysfunction or symptom is associated, early intervention (160% of normal diameter) can be done. As for the surgical procedure, replacement with composite conduit is the standard procedure for patients with congenital aortic valve malformations (bicuspid aortic valves and congenital aortic stenosis) and for most patients with congenital heart disease. A valve-sparing operation can be performed in patients with Marfan syndrome and in selected patients with aortic root dilation after surgery for complex CHD. Finally, the midterm results were excellent for both procedures.
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Abstract
Introduction
