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a The Children's Hospital Heart Institute, Aurora, Colorado
b University of Colorado Denver Health Sciences Center, Aurora, Colorado
Accepted for publication January 30, 2009.
* Address correspondence to Dr Mitchell, 13123 E 16th Ave, Box B200, Aurora, CO 80045 (Email: mitchell.max{at}tchden.org).
Presented at the Fifty-fifth Annual Meeting of the Southern Thoracic Surgical Association, Austin, TX, Nov 5–8, 2008.
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Abstract |
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Methods: Congenital SVAS repairs from 1988 to 2008 were retrospectively reviewed. Peak instantaneous gradients were estimated by Doppler interrogation. Variables were compared by either Student's t test or Fisher's exact test. Risk factors were analyzed by 
2 test. Survival was estimated by the Kaplan-Meier method.
Results: Of 25 primary SVAS repairs, there were 10 all-autologous slide aortoplasties and 15 prosthetic patch aortoplasties. The prosthetic patch group included the Doty technique (n = 9), patch-augmented slide aortoplasty (n = 3), modified Brom technique (n = 1), interposition graft (n = 1), and two-sinus patch with transverse arch augmentation (n = 1). There was 1 early and 1 late death. Cumulative survival for all patients was 96% at 5 and 10 years. Event-free survival did not differ between groups (p = 0.481). There were 2 late reoperations (both were prosthetic patch patients with bicuspid aortic valve: 1 with recurrent aortic valve stenosis and 1 with aortic insufficiency). Bicuspid aortic valve was the only risk factor for reoperation (p = 0.003). Three patients weighing less than 10 kg with diffuse disease underwent attempted slide aortoplasty: 2 required patch augmentation and 1 had a recurrent gradient in less than 1 year postoperatively.
Conclusions: Outcomes after SVAS repair were good by any technique. No advantage to all-autologous slide aortoplasty was apparent at current follow-up. Based on our experience, slide aortoplasty is not recommended for small patients with diffuse disease.
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Introduction |
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The most widely reported techniques used to correct SVAS are the one-sinus patch aortoplasty of the noncoronary sinus, described by McGoon and associates [10], and the two-sinus repair with inverted bifurcated extended patch aortoplasty described by Doty and colleagues [11]. Long-term outcomes of these techniques have been suboptimal [8]. Although several three-sinus patch repairs have been recently described, no single technique has demonstrated clear superiority [9, 12–17].
Techniques employing inert patch augmentation have potential disadvantages, particularly in small children. Distortion resulting from somatic growth may lead to recurrent stenosis or aortic insufficiency due to asymmetric valve geometry. Reoperations can be complicated by dense adhesions at prosthetic patch sites. In 1993, Myers and coworkers described an all-autologous three-sinus repair in which flaps of the distal ascending aorta were advanced into three corresponding sinus incisions (Fig 1) [18]. We refer to this technique as "slide aortoplasty." Potential advantages of this technique include maintenance of valve symmetry, preservation of growth potential in smaller children, and elimination of prosthetic or inert material. As with other three-sinus repairs, this technique increases exposure of both coronary ostia to blood flow. A limited number of patients undergoing slide aortoplasty has been reported, and there are no comparative data for this procedure versus other techniques [7, 17, 18]. In one report, half of all patients who underwent this procedure required augmentation of the repair with patch material, suggesting that this technique may be more technically demanding [7].
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Material and Methods |
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TopAbstractIntroductionMaterial and MethodsResultsCommentDiscussionReferences |
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There were 14 male and 11 female patients. Median age at SVAS operation was 4.7 years (range: 3 months to 21 years). Median weight was 15.3 kg (range: 4.7 to 52.0 kg.). Eighteen patients (72%) had discrete disease, and seven (28%) had diffuse disease. Four patients had 6 prior cardiovascular operations (3 primary coarctation repairs, 1 redo coarctation repair, 1 patent ductus arteriosus ligation, and 1 redo transverse and descending aorta augmentation) [19]. No patient had undergone prior sternotomy or supravalvar aortic stenosis repair. Seventeen patients (68%) had associated cardiovascular abnormalities (Table 1). One or more concomitant procedures were performed in 7 patients (Table 2). There were 2 patients (8%) with bicuspid aortic valve, both of whom underwent concomitant aortic valvotomy at SVAS repair. Two patients had concurrent procedures for diffuse involvement of the ascending aorta and transverse arch. Before SVAS repair, only 1 patient had mild aortic insufficiency, and no patient had more than mild aortic insufficiency.
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Slide aortoplasty (Fig 1) was performed in 10 patients (9 discrete, 1 diffuse) (Table 3). To compare all-autologous slide aortoplasty repairs to prosthetic reconstructions, these patients were considered as the all-autologous (AA) group. All other patients (9 Doty technique, 3 patch-augmented slide aortoplasty, 1 hemiarch interposition graft, 1 two-sinus patch repair plus ascending/transverse arch augmentation, and 1 modified Brom) constituted the prosthetic patch (PP) group.
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Our most recently treated patient weighed less than 10 kg and had diffuse disease (Table 3). Because of our prior difficulties experienced with slide aortoplasty in similar patients, this patient was treated with a modified Brom technique (Fig 2D) [17].
Data Analysis
Serial two-dimensional Doppler echocardiograms were reviewed to determine estimated peak instantaneous gradients (by Bernoulli equation) and to assess for aortic valve abnormalities. Outcome variables considered were late death and reoperation on the aortic root. Continuous variables and categorical variables were compared between groups using the two-tailed Student's t test and Fisher's exact test, respectively. Potential risk factors for reoperation were assessed using Pearson's 2 test (continuous variables) and Fisher's exact test (categorical variables) and included age at surgery, weight at surgery, diffuse disease, Williams disease, bicuspid aortic valve, type of repair (PP versus AA), number of sinuses enlarged at SVAS repair (two versus three), coexisting cardiovascular lesion, history of prior cardiovascular operation, and concomitant procedure. Event-free survival was defined as freedom from death or reoperation on the aortic root. Survival was estimated by the Kaplan-Meier method, and event-free survival was compared using the log-rank test. Values of p less than 0.05 were considered significant. All statistical calculations were performed using SPSS software package, version 16.0 (SPSS, Chicago, IL).
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Results |
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Follow-Up
The mean follow-up for the entire series was 6.3 ± 4.5 years. Mean follow-up intervals for AA and PP groups were 7.0 ± 6.4 and 5.1 ± 3.5 years (p = 0.364), respectively.
Reoperations and Late Events
There were 3 reoperations in 2 patients. Both patients had prior Doty procedure (PP group) and valvotomy for bicuspid aortic valve. The first patient presented 14 years after SVAS repair with severe calcific aortic stenosis. A mechanical valve was placed with Nicks annulus enlargement [20]. At 2-year follow-up, the patient was well, with regression of left ventricular hypertrophy on echocardiogram. At 3-year follow-up, echocardiogram revealed a large left ventricular outflow tract pseudoaneurysm with moderate concentric subvalvular obstruction. At reoperation, the pseudoaneurysm originated from a dehisced portion of the of the Nicks patch below the sewing ring of the prosthetic valve. Aortic root replacement with a mechanical valve conduit and Konno ventriculoplasty were performed as previously described [21].
The other patient had a primary SVAS repair with valvotomy at 1 year of age. Progressive aortic insufficiency and moderate restenosis required reintervention, and a Ross procedure was performed at age 11. On univariate analysis, bicuspid valve was the only significant risk factor for reoperation (p = 0.003).
Cumulative event-free survival for the entire cohort was 96% at 5 years and 80% at 10 years. No difference in cumulative event-free survival was evident between the AA and PP groups (p = 0.481).
Group Comparisons
Overall characteristics and group comparisons are presented in Table 4. The only demonstrable difference between groups was a greater prevalence of concomitant procedures in the PP group (p = 0.028). Additionally, there was a trend toward shorter hospital stay in the AA group (p = 0.079).
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The overall mean peak instantaneous gradient decreased to 14 ± 8 mm Hg immediately after surgery. At a mean late examination interval of 4.6 years (time of most recent study, immediate preoperative gradient used for patients undergoing reoperation), the mean peak instantaneous gradient was 22 ± 18 mm Hg. At most recent assessment (PP group 5.5 years, AA group 3.1 years; p = 0.205), mean peak instantaneous gradients for PP and AA groups were 25 ± 19 mm Hg and 15 ± 13 mm Hg, respectively (p = 0.214; Figs 3 and 4). Moderate or greater recurrent obstruction occurred in 5 patients (4 PP, 1 AA). Both patients with bicuspid valve required reoperation (see Reoperations and Late Events). The 3 remaining patients with recurrent moderate stenosis all had diffuse disease. The first patient had a 48 mm Hg gradient 12.7 years after Doty procedure. The second patient underwent two-sinus patch augmentation with two-patch augmentation of the ascending/transverse arch and had a 43 mm Hg gradient at 5.3 years. The third patient had a 48 mm Hg gradient within 10 months of all-autologous slide aortoplasty. This patient was the smallest surviving AA patient (9.9 kg) and the only AA patient with diffuse disease. In all cases with moderate recurrent stenosis, left ventricular hypertrophy regressed after SVAS repair and has remained stable. Each of these patients had diffuse disease and by Doppler interrogation the region of flow acceleration was nonfocal (of note, the Bernoulli equation significantly overestimates the degree of stenosis when the area of flow acceleration is nonfocal). No patient who underwent patch augmentation of attempted slide aortoplasty has had more than mild recurrent stenosis.
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Comment |
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We adopted slide aortoplasty for SVAS repair in 1997. This transition occurred as we began to encounter a higher frequency of small patients with SVAS (2 patients weighing less than 10 kg before 1997, 6 patients less than 10 kg thereafter) (Table 3). Although our series contains the largest number of slide aortoplasty cases reported to date, we have not demonstrated an advantage of this procedure over prosthetic patch techniques.
Several factors limit the power of this study. The total patient population is relatively small. Small study populations are a common problem with rare lesions such as SVAS [6, 7, 14, 18]. Larger series with longer follow-up have enrollment periods up to double the current study [9, 15–17]. Although larger patient numbers improve study power, the magnitude of therapeutic changes that have occurred over the past 4 decades is so significant that the lengthy enrollment periods of other studies also places some limitation on clinical relevance to current practice. Follow-up in our series is relatively short, and it is possible that late outcome differences may subsequently emerge favoring one group over the other. At current follow-up, the results of both autologous and prosthetic patch techniques have been very good.
Supravalvar aortic stenosis occurs in a wide spectrum of severity and patient ages. As argued by others, we believe that no single technique is optimal for all cases [18]. In patients with discrete SVAS, slide aortoplasty is a simple, expeditious, and effective technique. However, slide aortoplasty has no advantage in cases with diffuse disease, because this technique does not augment the size of the ascending aorta. We used this technique in 3 small patients (less than 10 kg) with diffuse disease involving moderate hypoplasia of the ascending aorta (Table 3). These patients had no step up in vessel size through the transverse aortic arch, and we anticipated that the size of the ascending aorta would not require enlargement. In 2 of these patients, attempted slide aortoplasty required patch augmentation due to exposure difficulties and to prevent persistent obstruction at the sinotubular junction. Both patients have mild gradients out to 3.5 years of follow-up. The only small patient with diffuse disease in whom slide aortoplasty alone was performed now has moderate recurrent stenosis (estimated peak instantaneous gradient of 48 mm Hg at 10 months follow-up compared with 20 mm Hg early after surgery). Other authors have reported the need to patch augment 50% of patients who had the Myers technique, but the reason for this modification was not stated [17]. Given our experience, we do not recommend slide aortoplasty in cases with any degree of diffuse disease, particularly in smaller patients in whom adequate exposure of the aortic root can be challenging. We empirically favor three-sinus techniques; and in our most recent similar patient, the modified Brom technique was used with an excellent early result [17].
Slide aortoplasty should be most beneficial for small children with the most relative somatic growth remaining. However, in our experience, patients undergoing operation at lesser weights were more likely to have diffuse disease. Six of 7 patients having diffuse disease underwent operation at weights less than 10 kg. Only 2 patients in this weight range had discrete disease, and both presented early in the series and underwent Doty repairs. Conversely, only 1 patient had diffuse disease outside this weight range, weighing 37.1 kg at operation. This patient had severe tubular hypoplasia of the ascending aorta with a step up in size at the transverse arch. Interposition graft replacement into the transverse arch by hemiarch technique with tailored three-sinus enlargement at the proximal end of the graft has provided excellent relief of obstruction at more than 4 years follow-up.
The long-term outcomes of one- and two-sinus repairs are less than optimal, with significant incidences of late restenosis, regurgitation, and the need for reoperation [8]. Most series are heavily dominated by one-sinus repairs and have not shown advantages of any particular technique [9, 15, 16]. The only large series with an even distribution of one- and two-sinus repairs (including a small number of three-sinus repairs) demonstrated superior hemodynamic results, reduced mortality, and a lower incidence of reoperation for multiple-sinus repairs [17]. Another report similar in size to our study compared Brom's three-sinus repair to one-sinus standard patch aortoplasty, but no benefit of three-sinus repair was demonstrable [14]. Our study population included 11 two-sinus repairs and 14 three-sinus repairs. Analyzed by number of sinuses repaired, neither two-sinus nor three-sinus repair was a risk factor for reoperation in our experience. Others have noted that aortic insufficiency may occur after the Brom three-sinus repair if the patches are sized too large [14]. No patient undergoing three-sinus repair in our series had more than mild aortic insufficiency. New trace to mild aortic insufficiency developed in 6 of 15 PP patients and 4 of 10 AA patients at early assessment. At most recent follow-up assessment, the only patient in whom aortic insufficiency progressed was the patient with bicuspid valve who subsequently had a Ross procedure. Further follow-up is required to determine if late aortic insufficiency will be a problem in either cohort.
The management of patients with SVAS and concomitant bicuspid valve remains a matter of debate. Bicuspid valve was the only risk factor for reoperation in our patients, and both patients with bicuspid valve required reoperation. Although several prior series have demonstrated this finding [6, 15, 16, 22], a large series with lengthy follow-up did not find bicuspid aortic valve to be a risk factor for reoperation [17]. Some advocate primary Ross procedure in this scenario [7, 22]. Our patients with bicuspid valve were both less than 4 years of age at the time of SVAS repair. Although the Ross procedure is feasible at any age, it ensures reoperation on the right ventricular outflow tract. Our patients did not require reoperation for a decade or more. Delaying aortic valve replacement into adolescence expands the options for valve replacement and seems reasonable.
In conclusion, repair of SVAS by all methods had excellent results, except in patients with bicuspid aortic valve. There was no apparent advantage to all-autologous slide aortoplasty at current follow-up. Slide aortoplasty is a simple and effective procedure for patients with discrete SVAS, and longer follow-up is required to determine if slide aortoplasty will prove superior to prosthetic patch techniques in these patients. All-autologous slide aortoplasty cannot be recommended for smaller patients with diffuse involvement of the ascending aorta. The tendency for smaller patients with diffuse disease to require patch augmentation at the time of slide aortoplasty obviated the primary advantage of this procedure in these patients.
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Discussion |
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LT SCOTT: Yes, sir.
DR FRASER: Thank you for your service to our country and thank you for putting together this excellent presentation.
LT SCOTT: Thank you very much.
DR FRASER: I will just cut to the chase. You sent me the manuscript well in advance, it is well written, and I look forward to seeing it in print. And I agree with your conclusions that you haven't demonstrated a difference in outcome between techniques, so it leaves the surgeon to tailor his methodology to the patient's anatomy. You have already answered one of my questions, and that is, how do you select these patients?
Another question that you didn't really allude to in your presentation is what diagnostic methodology should be incorporated into the management scheme? I believe the majority of your patients were diagnosed with echocardiography, but you did have one patient that died after cardiac catheterization. So what would you recommend for a patient presenting with those problems? Specifically, you have identified that patients with diffuse disease have a poorer outcome and are more difficult to manage. So how are you going to sort that out?
LT SCOTT: Thank you, Dr Fraser, and those are very excellent questions and very important topics, especially in this unique patient population. Our modality of workup, as you mentioned, is primarily echocardiography. Because of our 1 patient who suffered an arrest during catheterization and two others who arrested shortly after induction in the operating room, we are hesitant to use anesthesia whenever considering a work-up. In fact, a predisposition to arrest during anesthesia or catheterization has been documented in the literature. Nevertheless, there are times when further work-up is required. When necessary, such as with diffuse disease, especially with involvement of the brachiocephalic arteries or with distal pulmonary involvement, then we will opt for cardiac catheterization over magnetic resonance imaging, mainly because of the availability of emergent supportive measures such as extracorporeal membrane oxygenation.
DR FRASER: I have another question that I know is a little bit beyond the scope of your presentation but I am just curious about your approach in Denver. Many of the patients with diffuse disease will have severe bilateral branch pulmonary artery stenosis, and those can be controversial in terms of management, and I would be interested in your approach to those patients.
LT SCOTT: In actuality, we did take a look at that. In our experience, especially in patients with Williams syndrome, it is not uncommon to see significant involvement of the pulmonary arterial system. It has been documented that the usual course of the pulmonary system is actually a regression of disease, in contrast to the aortic system. In our situation, we had 4 patients who did require branch pulmonary artery patches. In those situations, we would usually opt for repair only if there is evidence of severe obstruction or severe stenosis in the distal pulmonary artery system, or if there was moderate or greater central pulmonary artery involvement.
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