Pediatr Cardiol (2012) 33:1131–1137 DOI 10.1007/s00246-012-0267-y
ORIGINAL ARTICLE
Pulmonary Stenosis is a Predictor of Unfavorable Outcome After Surgery for Supravalvular Aortic Stenosis Jelena Kasnar-Samprec • Ju¨rgen Ho¨rer • Hanna Bierwirth • Zsolt Prodan • Julie Cleuziou • Andreas Eicken • Ru¨diger Lange • Christian Schreiber
Received: 30 September 2011 / Accepted: 21 February 2012 / Published online: 22 March 2012 Ó Springer Science+Business Media, LLC 2012
Abstract We sought to evaluate whether the presence of pulmonary stenosis (PS), amongst other factors, influences the mortality and the rate of reoperations in the long-term follow-up of patients with supravalvular aortic stenosis (SVAS). We identified all patients with SVAS from our surgical database. The patients with multi-level aortic stenosis or concomitant cardiac procedures were excluded from this study. Follow-up (100 %) was conducted between 2008 and 2010. Twenty-six patients underwent surgery for SVAS between 1974 and 2006. Seventeen patients (65 %) were diagnosed with Williams-Beuren-Syndrome, six (17 %) had a diffuse form of SVAS and 10 (39 %) had PS. No patient had a surgical or interventional procedure for PS at the initial operation or during follow-up. There was no statistically significant association between PS and WBS (p = 0.30) or diffuse form of SVAS (p = 0.13). Patients with PS were operated at younger age (p = 0.028). Median follow-up time was 14.6 years. Overall mortality was 11.5 %. One patient with preoperatively severely decreased LV-function died 27 days postoperatively. Two late deaths occurred 7 and 10 years after the initial operation. Reoperations were required in 4 patients (15 %), 4–19 years after the original operation, due to aortic arch stenosis, supravalvular restenosis or poststenotic aortic dilatation. PS was found to be a
J. Kasnar-Samprec (&) J. Ho¨rer H. Bierwirth Z. Prodan J. Cleuziou R. Lange C. Schreiber Department of Cardiovascular Surgery, Deutsches Herzzentrum Mu¨nchen an der Technischen Universita¨t Mu¨nchen, 80636 Munich, Germany e-mail:
[email protected] A. Eicken Department of Pediatric Cardiology and Congenital Heart Defects, Deutsches Herzzentrum Mu¨nchen an der Technischen Universita¨t Mu¨nchen, 80636 Munich, Germany
risk factor for reoperation (p = 0.005) and for the combined reoperation/death end-point (p = 0.003). PS in patients with SVAS is a risk factor for reoperations in the aortic region and might be considered an indicator of the severity of the arterial disease and a predictor of an unfavourable outcome. Keywords Congenital heart disease Supravalvular aortic stenosis Outcomes Pulmonary arteries Aortic restenosis
Introduction Congenital supravalvular aortic stenosis (SVAS) is the least common form of left-ventricular outflow-tract obstruction (LVOTO) [1]. SVAS is strongly associated with Williams-Beuren syndrome (WBS), but it also occurs in a familial form or as sporadic cases. A mutation of the elastin gene on chromosome 7q11.23 [10] and the consequential defective elastin production result in severe compensatory medial thickening in the large systemic elastic arteries [18]. The resulting luminal obstruction ranges from the typical localized aortic narrowing above the level of the sinotubular junction to diffuse aortic narrowing extending into the arch and brachiocephalic vessels [19]. Pulmonary arteries may also be affected [22] in a form of pulmonary valve stenosis, SVAS, or peripheral pulmonary artery (PA) stenosis. Recognition that SVAS is not only a disease of the supravalvular aorta but of the entire aortic root [18], has led to new operative techniques that try to preserve the integrity of the aortic root [7, 9, 13]. Certain factors including younger age at first surgery, diffuse form of disease, coexistent valvular aortic stenosis, bicuspid aortic valve, PA stenosis, as well as incomplete gradient relief at the
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original surgery have been implicated as indicators for increased risk of reoperation [2, 4, 15, 16, 20]. According to the literature, a relatively high percentage of SVAS patients require surgical or interventional relief of pulmonary stenosis (PS) at the time of primary SVAS surgery [8, 9, 12, 16] Preoperative dilation of peripheral and central PA stenoses in certain cases helps to decrease the risk of right-ventricular failure during the postoperative course [6, 11, 17]. Bilateral outflow-tract obstruction is also known to increase mortality risk in WBS patients [3]. The purpose of this retrospective study was to identify risk factors for death or reoperation in patients with SVAS, treated at our institution, with special regard to patients with PS.
Patients and Methods Patient Selection We identified all patients with SVAS from our institutional cardiothoracic surgical database. Patients with multilevel LVOTO, as well as the patients with previous or concomitant cardiac surgery, were excluded from this study. Medical records of each patient were reviewed for demographic information, medical history, primary diagnosis, echocardiography/angiography details, and details of initial and subsequent surgeries and interventions. Standardized questionnaires were sent to the patients or their parents. The physicians and cardiologists caring for the patients were contacted to receive the detailed follow-up information. Follow-up was conducted between 2008 and 2010 and is 100 % complete. Data Analysis The primary end point of the study was time to first reoperation or death. Continuous variables are expressed as mean and SD if normally distributed or median and range for nonnormal distribution. Continuous variables and categorical variables were compared between groups using twotailed unpaired Student t test and Fisher’s exact test, respectively. Event-free survival was defined as freedom from death or reoperation. Survival estimates were calculated using the Kaplan–Meier method, and comparisons between survival distributions were made using the log-rank test. Potential risk factors for reoperation and/or mortality that were assessed included the following: age at surgery, sex, weight at surgery, PS, systemic artery stenosis, WBS, diffuse disease, cardiopulmonary bypass (CPB) time, aortic cross-clamp (AoX) time, type of repair (Doty versus McGoon), and prerepair/postrepair/last follow-up gradient across LVOT. A probability value \0.05 was considered
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statistically significant. All data were analyzed using SPSS software, version 18.0 (SPSS, Chicago, IL). Institutional Review Board approval was obtained to conduct this retrospective follow-up study, for which the need for patients to provide informed consent was waived. The investigators had full access to the data and take full responsibility for the integrity of the data.
Results Patient Characteristics and Preoperative Variables Between August 1974 and October 2006, 26 patients underwent surgery for congenital SVAS. Eight of them were female (31 %), and 18 were male (69 %). Age at the time of primary surgery ranged between 6 months and 26 years (median 8.8 years). Weight at this time ranged between 5.9 and 84 kg (median 24 kg). Seventeen patients (65 %) were diagnosed with WBS; in 1 patient a familiar form of SVAS was suspected; and the SVAS of the remaining patients (30 %) was classified as sporadic. SVAS was classified as localized in 20 patients (77 %) and as diffuse in 6 patients (23 %). Additional artery stenosis was present in 13 patients (50 % [Table 1]). Five patients had PA stenosis; 3 had a systemic (brachiocephalic, mesenterial or renal) artery stenosis; and 5 had both pulmonary and systemic artery stenosis. In addition, 1 patient had a hypoplastic abdominal aorta; 1 patient had widening of a coronary artery; and 1 patient was diagnosed with aneurysm of the sinus valsalvae. Preoperative left ventricle–to–aorta maximal gradients were measured by cardiac catheterization or echocardiography and ranged between 37 and 135 mm Hg (mean 73 ± 27 [median 67]). One patient had mild aortic insufficiency before SVAS repair, whereas the remaining patients had minimal or none. Before surgery, one patient had severely decreased LV function; two patients had mildly decreased LV function; and LV function in the remaining patients was described as good. Intraoperative Data Sixteen patients who underwent surgery before 1998 were treated by McGoon technique; afterward, in 10 patients, Doty’s inverted bifurcated patch plasty was used. The patch material included Gore-Tex, Gore (n = 20), Dacron, Bard (n = 3), homograft (n = 2), and Hemashield, Maquet (n = 1). CPB time was 64 ± 32 minutes, whereas AoX time averaged 39 ± 19 minutes. Mean CPB and AoX times were lower in the McGoon group (50 ± 24 and 31 ± 15 minutes) than in the Doty group (95 ± 27 and 52 ± 16 minutes); however, this difference was statistically insignificant
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improvement. Another patient, with a diffuse form of the disease, was found dead in his bed 7 years after primary surgery, which was performed at 9 years of age. The patient had intraoperatively identified widening of the right coronary artery as well as known mild mitral insufficiency and peripheral PS (PPS). The death was presumed to be due to cardiac causes. The third patient died 10 years after original SVAS repair, which was performed at 5 years of age, due to an uncontrollable infection and was not cardiac related. All of the patients who died were males diagnosed with WBS and were treated by McGoon technique. These parameters were not found to be isolated risk factors for mortality (sex p = 0.24, WBS p = 0.14, surgery method p = 0.27), just like none of the other investigated factors. For the surviving patients, mean follow-up was 18.6 ± 10.9 years (range 3.7 to 34.9 [median 17.7]). During this time, reoperations were required in 4 patients (15.4 %), all due to recurrent high LV-to-aorta gradients. Two patients were reoperated for stenosis in the aortic arch 4 and 8 years after the initial procedure, respectively. In both patients, patch aortoplasty with Gore-Tex was performed in with the patient under deep hypothermia with circulatory arrest. One reoperation was performed 6 years after surgery due to aortitis with multiple aortic arch aneurysms. In this case, it was necessary to replace the ascending aorta and the aortic arch with Gore-Tex prosthesis, including reimplantation of the brachiocephalic vessels. The last patient needed a reoperation for SVAS 19 years after original McGoon surgery. The old Dacron patch was excised, and the noncoronary sinus and the ascending aorta were widened using a Gore-Tex patch. Indications and time for reoperation, as well as patient demographics, diagnoses, and intraoperative data for initial SVAS repair, are listed in Table 2.
(p = 0.40 and p = 0.37, respectively). In 3 of 6 patients with diffuse disease, deep hypothermia with circulatory arrest was used to enlarge the aortic arch. Intraoperatively, aortic wall thickening was described as significant in 5 patients. Aortic valve consisted of 3 leaflets in all patients, and no thickening of the aortic leaflets was found during the procedures. Except for 1 case of patent ductus arteriosus ligation, no other concomitant procedure was performed at the time of the primary surgery for SVAS repair. Mortality and Reoperations Mean duration of follow-up was 17.7 ± 11.1 years (range 27 days to 34.9 years [median 14.6 years]) for all patients. Overall mortality was 11.5 %. One patient died 27 days after surgery (early mortality 4 %). The patient underwent surgery at 12 years of age and before surgery had severely decreased LV function due to severe localised SAVS (inner diameter of the aorta was 5 mm). The patient also had diagnosed mitral stenosis. The postoperative course was complicated with rhythm disturbances, and LV function showed no signs of Table 1 Number and percentage of SVAS patients with additional arterial stenoses Arterial stenosis
Patients No.
%
Supravalvular PS
1
4
PPS
9
35
Renal artery stenosis Mesenterial artery stenosis
5 2
19 8
Brachiocephalic arteries stenosis
3
12
Hypoplastic abdominal aorta
1
4
Table 2 Reoperated patients: Demographics, additional diagnoses, and intraoperative data for initial SVAS repair Patient no.
1
Diagnosesa
Operative data for the initial SVAS repair
Reoperation
Demographics
Indication and time after primary surgery
Age at original surgery
Sex
WBS
Diffuse SVAS
PS
Systemic artery stenosis
Surgery
CPB (min)
Supravalvular restenosis
4.3 years
Male
0
0
1
1
McGoon
50
33
0
5.9 years
Female
1
1
1
1
McGoon
52
34
0
6.4 months
Male
1
0
1
0
Doty
102
39
0
9.0 months
Female
1
1
1
0
Doty
149
84
49
AoX (min)
Circulatory arrest (min)
19.0 years 2
Stenosis in aortic arch 7.9 years
3
Aortitis with multiple aneurysms in aortic arch 6.2 years
4 a
Stenosis in aortic arch 3.8 years
Existence of a diagnosis is depicted by ‘‘1’’
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Figure 1 shows the maximal LV-to-aorta pressure gradients in the four reoperated patients and compares them with those of nonreoperated, living patients. During the entire follow-up period, 19 of 26 patients (73 %) were ‘‘event-free’’ (living and not reoperated). Table 3 lists the factors examined as potential risk factors for mortality, reoperations, and combined mortality/reoperation end point. PA Stenosis PA stenosis was diagnosed in 10 patients (39 %). In 9 patients, PPS was present, whereas 1 patient had mild SVAS. Preoperative and operative parameters were compared between the group of patients with PS (10 patients [PS group]) and the group without PS (16 patients [non-PS group]), and the results are listed in Table 4. Freedom from mortality and reoperation for the two groups is shown in Fig. 2. Median time to combined mortality/reoperation end point for the PS patients, as estimated by Kaplan-Meier curve, was 10.5 years (95 % confidence interval 8.4 to 23.8). Altogether, 2 of 3 patients Fig. 1 Maximal LV-to-aorta pressure gradients in the four reoperated patients (black lines) and the mean pressure gradients of nonreoperated, living patients (‘‘event-free’’ patients red line)
who died, as well as all patients who had to be reoperated (due to recurrent gradient in aorta) had PS, which was found to be a risk factor for reoperation alone (p = 0.005) as well as the combined mortality/reoperation end point (p = 0.003). At last follow-up, there was no significant difference in LV-to-aorta pressure gradients between the two groups (17 ± 15 in non-PS and 13 ± 12 mmHg in PS, p = 0.46). During the entire follow-up period, no patient underwent a surgical or interventional procedure for PS.
Discussion In our current retrospective study, we conducted long-term follow-up of patients with SVAS who were treated at our institution to identify risk factors for death and/or reoperation. Extensive research during past decades has led to a better understanding of the underlying genetic pathology in patients with SVAS. Because it has become widely accepted that SVAS is a part of the general disease of the
140 120 100
1 2 3 4 Event-free patients
80 60 40 20 0 Before primary operation
Intraoperative
Before reoperation
Last follow-up
Table 3 Potential risk factors for the mortality, reoperations, and the combined mortality/reoperation end point Risk factor
p Mortality
Reoperation
Combined
Age at original surgery \ 8.8 years (median)
0.692
0.029a
0.155
Sex
0.239
0.349
0.961
WBS
0.142
0.305
0.078
Diffuse SVAS
0.617
0.141
0.132
PS
0.226
0.005a
0.003a
Systemic artery stenosis
0.887
0.314
0.372
Surgery method (McGoon or Doty)
0.269
0.194
0.867
CPB time [ 64 min (mean)
0.319
0.005a
0.005a
AoX time [ 39 min (mean)
0.790
0.079
0.250
Circulatory arrest during surgery
0.585
0.261
0.627
Mean preoperative pressure gradient [ 73 mmHg (mean) Mean postrepair pressure gradient [ 15 mmHg
0.458 0.348
0.504 0.576
0.977 0.280
a
Depicts a statistically significant result
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Pediatr Cardiol (2012) 33:1131–1137 Table 4 Comparison of preoperative, intraoperative, and postoperative variables between the PS and non-PS groups of patients
a
Depicts a statistically significant result
*
1135
Variable
PS group
Non-PS group
p
Mean age at original surgery (years)
4.4 ± 2.7
12.2 ± 7.1
0.028a
Sex (M/F)
8/2
10/6
0.420
William Beuren syndrome
8/10
9/16
0.399
Diffuse SVAS
4/10
2/16
0.163
Systemic artery stenosis
5/10
3/16
0.189
Surgery method
4/10 Doty, 6/10 McGoon
6/16 Doty, 10/16 McGoon
1.000
Mean CPB time (min)
77 ± 40
54 ± 22
0.048a 0.140
Mean AoX time (min)
46 ± 21
34 ± 15
Circulatory arrest
2/10
1/16
0.538
Mean preoperative (mmHg)
77 ± 27
71 ± 28
0.980
Postrepair gradient (mmHg)
16 ± 17
15 ± 18
0.866
*
*
Patients at risk 16
14
12
9
8
6
3
10
8
4
3
2
2
1
Fig. 2 Kaplan–Meier curve showing time to combined mortality/ reoperation end point for the patients with (PS group red line) and without PS (non-PS group blue line). The number of patient at risk is shown in the corresponding colors. Asterisk (*) on the right-hand side of a vertical line, showing censored data, depicts mortality (nonmarked vertical line corresponds to a reoperation)
arterial wall [18], we investigated the impact of PS in patients with SVAS on mortality and reoperation rates. Certain factors—including younger age at first surgery, diffuse form of disease, coexistent valvular aortic stenosis, bicuspid aortic valve, PA stenosis, as well as incomplete gradient relief at original surgery—have been identified as markers for increased risk of reoperation [2, 4, 15, 16, 20]. In our patient population, we found the following risk factors to be significant for the risk of reoperation: age \ 8.8 years, CPB time [ 64 minutes at the time of
initial SVAS surgery, and presence of PS. The presence of PS and CPB time [ 64 minutes also proved to be significant risk factors for the combined mortality/reoperation end point. It is, however, important to point out that all of the patients with a primary diagnosis of multilevel LVOTO, as well as all of the patients with concomitant cardiac procedure at the time of SVAS repair, were excluded from this study. Therefore, we were not able to evaluate some of the earlier recognised mortality/reoperation risk factors (e.g., bicuspid aortic valve [13], concomitant procedure at repair [9, 14]). RVOTO has been described in up to 83 % of the patients with WBS, familial elastin arteriopathy, or sporadic nonWilliams SVAS [18, 21]. The most common form of RVOTO in SVAS patients is peripheral PA stenosis followed by central PA stenosis, whereas supravalvular PA stenosis seems to be the rarest form [3]. It has been reported that balloon angioplasty of PAs in the patients with elastin arteriopathy seems to be less effective than the dilatation in other forms of PA stenosis and is perhaps best reserved for cases of distal lesions [5]. Several reports have indicated that during the natural course of the disease, the severity of PA stenoses decreases throughout childhood and adolescence [3, 17, 21]. Collins et al. [3] reported a large series of 270 patients with WBS and discussed the long-term outcomes of cardiovascular abnormalities. They reported that patients with mild PPS, those with moderate PPS who did not required intervention by 10 years of age, and those with severe PPS who did not required intervention by 5 years of age are unlikely to need it in the future. In our cohort, WBS was present in 17 patients (65 %), and PA stenosis was present in 39 % of the patients. There was no statistically significant association between PS and WBS (p = 0.30). In accordance with our current hospital policy to conservatively treat PS in patients with SVAS, none of the patients in our series underwent a preoperative or intraoperative procedure due to RVOTO. During the entire follow-up period, no patient required interventional
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or surgical relief of PS because even the more pronounced stenoses tended to regress. Different groups have reported a relatively high percentage of SVAS patients who undergo surgical or interventional relief of PS at different times. Some have argued that preoperative dilation of PA stenoses in certain cases helps decrease the risk of right-ventricular failure during the postoperative course [6, 11, 17]. Others have reported performing concomitant PA surgery at the time of primary SVAS surgery [8, 9, 12, 16], and some have reported reoperations or reinterventions in the RVOT [8]. Stamm et al. [17] discussed their experience in surgery for bilateral outflow-tract obstruction in patients with elastin arteriopathy. They reported a series of 33 patients with SVAS and RVOTO, 70 % of whom were diagnosed with WBS. In 18 patients (55 %), PA stenosis was addressed before or at the time of SVAS surgery. Eight patients (33 %) underwent preoperative percutaneous balloon dilatation of PA stenosis, whereas 15 (45 %) underwent surgical augmentation of PA. In their series, 3 reoperations were necessary (9 %), 2 of them for recurrent/residual PA stenosis. In an additional 6 patients (18 %), balloon dilatations of PA stenosis were performed during the follow-up period. In the 15 patients in whom treatment of RVOTO was not indicated before or at the time of SVAS surgery (the majority of whom had initially milder stenoses), there was no need for reoperation or intervention during follow-up. Necessity of surgical or interventional treatment before or at the time of SVAS surgery was found to be a risk factor for reoperation or reintervention during follow-up. Whereas Stamm et al. [17] evaluated results in patients with combined SVAS and PS and made a distinction between groups based on need for PS treatment, we compared a group of patients with and a group of patients without PA stenosis. Imamura et al. [8] have also identified PS as a risk factor for reoperation. They reported a series of 49 patients who underwent surgery for SVAS. Forty-seven percent of the patients underwent branch PA repair at the time of SVAS surgery. The group reported 16 patients who required reoperation. Fifty-six percent of the reoperated patients underwent a procedure on the RVOT at the time of reoperation, with some of them being reoperated exclusively due to RVOTO. As stated previously, in our cohort, during the entire follow-up period, no patient required interventional or surgical relief of PS. All of the four necessary reoperations were performed due to recurrent gradients in the aortic area. In our cohort, the patients with diagnosed PA stenosis required primary surgery for SVAS at a statistically significant younger age, which is in accordance with the results of Stamm et al. [17] and Imamura et al. [8] A longer CPB time was also found in this group. Although patients with PS did not have diffuse disease more often than the
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others (p = 0.13), longer CPB time might indicate that these patients pose a greater surgical challenge during SVAS correction, perhaps due to different tissue quality or younger age at the time of surgery. Although the patients treated at our institution underwent no surgical or interventional procedures on PAs, and although the reoperations were performed exclusively in the aortic area, PS was still found to be a risk factor for reoperation and for the combined reoperation/mortality end point. All of these findings point to PS being a sign of a more severe form of the arterial disease in patients with SVAS. Limitations of the Study The present study was retrospective and included patients diagnosed with SVAS at our hospital during the course of more than three decades. We used imaging reports rather than an independent review of each examination, which can lead to missing information. The operative technique was changed chronologically, not patient specifically. The study was based on a relatively small number of patients, which precluded multivariate analysis and certainly limited the value of statistical analysis.
Conclusion SVAS is a part of genetic disease that causes medial thickening in the large systemic elastic arteries. PA stenosis in patients with SVAS is a risk factor for reoperation in the aortic region and might be considered an indicator of the severity of the arterial disease as well as a predictor of unfavourable outcome.
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