Pediatr Cardiol (2006) 27:713–719 DOI 10.1007/s00246-006-1321-4
Echocardiographic Follow-Up of Congenital Aortic Valvular Stenosis Ayse Guler Eroglu Æ Kadir Babaoglu Æ Leven Saltık Æ Funda Oztunc¸ Æ Tevfik Demir Æ Gulay Ahunbay Æ Alper Guzeltas Æ Gu¨rkan C¸etin
Received: 11 January 2006 / Accepted: 18 July 2006 Springer Science+Business Media, Inc. 2006
Abstract We investigated the morphology of the stenotic aortic valve, the progression of the stenosis, and the onset and progression of aortic regurgitation (AR) in patients with congenital aortic valvular stenosis (AVS). The medical records of 278 patients with AVS were reviewed, with the patients with concomitant lesions besides AR excluded. Very mild aortic stenosis was defined as a transvalvular Doppler peak systolic instantaneous gradient (PSIG) less than 25 mmHg, mild stenosis as 25–49 mmHg, moderate stenosis as 50–75 mmHg, and severe stenosis as more than 75 mmHg. The mean age of the patients was 4.9 ± 4.3 years (range, 3 days to 15 years), and 203 (73%) were male. The number of the cusps was determined with two-dimensional echocardiography in 266 patients (95%): unicuspid in 3 patients (1%), bicuspid in 127 patients (48%), and tricuspid in 136 patients (51%). A total of 192 of all patients were followed for 2 months to 14.6 years (mean 4.2 ± 3.3 years) with medical treatment alone. Among 72 patients with very mild stenosis at initial echocardiographic examination, 20% had mild, 3% moderate, and 1% severe stenosis after a mean period of 3.7 years. In 70 patients with mild stenosis at initial echocardiographic examination, 28% had moderate and 9% severe stenosis after a mean period of 5 years. Among 44 pa-
tients with moderate stenosis at initial echocardiographic examination, 36% had severe stenosis after a mean period of 3.7 years. Among 192 patients, 40% had AR (3% trivial, 28% mild, and 9% moderate) at initial echocardiographic examination. After a mean period of 4.2 years, 58% of the patients had AR (13 % trivial, 25% mild, 16% moderate, and 4% severe). There was not statistically significant difference between catheterization peak systolic gradients (47 ± 16 mmHg) and Doppler estimated mean gradients (45 ± 9 mmHg) (p = 0.53), whereas Doppler PSIGs (74.9 ± 15.7 mmHg) were higher than catheterization peak systolic gradients (p < 0.0001) in 25 patients who were studied in the catheterization lab. Patients with very mild stenosis may be followed with a noninvasive approach every 1 or 2 years, and an annual follow-up is suggested for patients with mild stenosis. Nearly one-third of patients with moderate stenosis at initial echocardiographic examination had severe stenosis after a mean period of 3.7 years. Therefore, we recommend, that patients with moderate stenosis undergo noninvasive evaluation every 6 months. Doppler estimated mean gradient is very useful in predicting the need for intervention in children with AVS. Keywords Aortic valvular stenosis Æ Aortic regurgitation Æ Bicuspid aortic valve
A. G. Eroglu (&) Æ K. Babaoglu Æ L. Saltık Æ F. Oztunc¸ Æ T. Demir Æ G. Ahunbay Æ A. Guzeltas Division of Pediatric Cardiology, Department of Pediatrics, Istanbul University Cerrahpas¸ a Medical Faculty, 80303 Aksaray, Istanbul, Turkey E-mail:
[email protected] G. C ¸ etin Istanbul University Institute of Cardiology, 80303 Aksaray, Istanbul, Turkey
Introduction Aortic valvular stenosis (AVS) accounts for approximately 3–7% of all congenital heart disease and frequently has a progressive course [6, 8, 21, 28]. The natural history of moderate and severe stenosis was
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well documented with cardiac catheterization in several studies in the report from the second joint study on the natural history of AVS [6, 8]. Patients were studied in a cross-sectional manner by echocardiography [17]. There are limited data regarding echocardiographic follow-up of children with congenital AVS [9]. This study evaluates the morphology of the stenotic valve, the progression of the stenosis, and the onset and progression of aortic regurgitation (AR) in 278 patients with congenital AVS.
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aortic valve, mild for not reaching the tip of the mitral valve, moderate for regurgitation reaching the tip of the mitral valve, and severe for regurgitation beyond the tip of the mitral valve. Data are expressed as mean ± standard deviation. Student’s t–test was used to compare variables. The chi-square test was used to assess differences between groups for categorical variables. Statistical significance was inferred at p < 0.05. Analysis was done using SPSS software (version 11.0; SPSS, Chicago, IL, USA).
Results Materials and Methods Patients The study population consisted of 278 patients with congenital AVS evaluated and followed with echocardiography at our institution from 1990 to 2004. Patients with incomplete medical records, abnormal ventricular functions, and concomitant lesions other than AR were excluded. Transthoracic echocardiography was performed with a transducer of either 3.5 or 7 MHz interfaced with an Acuson 128/XP 10 or a Vivid 3 ultrasound system. Two-dimensional, M-mode, color-flow Doppler, pulsed Doppler, and continuous-wave Doppler echocardiography were used in all patients. The last examination prior to surgery or balloon valvuloplasty provided our final measurements. The number of aortic valve cusps was evaluated from a parasternal short-axis view with two-dimensional echocardiography. Continuous-wave Doppler was used through the suprasternal notch or right parasternal windows to record the maximum peak systolic instantaneous gradient (PSlG = 4 · maximum velocity2), across the aortic valve. The Doppler mean gradient was not available for all patients and was estimated as mean gradient (2.4 · maximum velocity2), eliminating the need to trace the Doppler velocity curve [23]. The severity of the aortic stenosis was graded according to Doppler PS1G measurements [7, 11, 14]. Very mild aortic stenosis was defined as a transvalvular Doppler gradient less than 25 mmHg, mild stenosis as 25–49 mmHg, moderate stenosis as 50–75 mmHg, and severe stenosis as more than 75 mmHg. A semiquantitative estimate of the severity of AR was made by using color-flow and pulsed-wave Doppler echocardiography [15, 16, 18, 22, 25, 29]. Color-flow images of the aortic regurgitant jet were obtained from the parasternal long-axis view. Mapping of the regurgitant jet by pulsed Doppler was performed from the apical five-chamber view. The degree of AR was rated as trivial for regurgitated jet limited to just below the
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At the time of initial echocardiographic examination, the mean age of the 278 patients was 4.9 ± 4.3 years (range, 3 days to 18 years; median, 4.3 years), as depicted in Table 1. Two hundred three of 278 patients were male (73%) (male: female ratio, 2.7). One hundred ninety-two patients were followed for a mean of 4.2 ± 3.2 years (range, 2 months to 14.6 years, median, 3.3 years) with echocardiography. Among the 192 patients, 60 were younger than 2 years of age. The mean initial Doppler PSIG in children younger than 2 years old was higher than in those older than 2 years (41.7 ± 20.6 vs. 34.6 ± 18.4 mmHg, respectively; p = 0.01). Aortic Valve Morphology The number of cusps was determined by two-dimensional echocardiography in 266 patients (95%); the valve was thought to be unicuspid in 3 patients (1%), bicuspid in 127 patients (48%), and tricuspid in 136 patients (51%). Patients with a bicuspid and a tricuspid valve at initial echocardiographic examination were of similar age (4.4 ± 4.5 vs 5.1 ± 4 years, respectively; p = 0.14) and had similar Doppler PSIGs (47.5 ± 28.1 vs 41.9 ± 30.1 mmHg, respectively; p = 0.11). The follow-up period for the patients with a bicuspid valve was longer than that for those with a tricuspid valve (4.2 ± 3.7 vs 3.3 + 2.8 years, respectively; p = 0.04). Valvular Stenosis and Regurgitation The severity of AVS at initial echocardiographic examination according to age groups is presented in Table 2. Twenty-four percent of the patients younger than 1 month of age and 23% of patients between 1 month and 1 year of age had severe AVS, whereas 5%
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Table l Patient age at initial echocardiographic examination Age
No.
%
< 1 month < 1 month–1 year 1.1–5 years 5.1–10 years >10 years Total
29 53 66 89 41 278
10.4 19.1 23.7 32 14.8 100
of the patients between 1.1 and 5 years, 10% of patients between 5.1 and 10 years, and 14% of the patients older than 10 years of age had severe AVS at initial echocardiographic examination. The degree of AR according to the severity of AVS at initial echocardiographic examination is presented in Table 3. Patients with very mild stenosis had the least AR (32%). Two of three patients with severe AR had severe AVS and the other one moderate AVS, at initial echocardiographic examination. The course of AVS in 192 patients who were followed with echocardiography are presented is Table 4. Seventy-two (38%) of them had very mild, 70 (36%) mild, 44 (23%) moderate, and 6 (3%) severe stenosis, at initial echocardiographic examination. Among 72 patients with very mild stenosis at initial echocardiographic examination, 20% had mild, 3% moderate, and 1% severe stenosis after a mean period of 3.7 years. In 70 patients with mild stenosis at initial echocardiographic examination, 28% had moderate
and 9% severe stenosis after a mean period of 5 years. Among 44 patients with moderate stenosis at initial echocardiographic examination, 36% had severe stenosis after a mean period of 3.7 years. The course of AR according to the severity of AVS in 192 patients followed with echocardiography is presented in Table 5. Of 192 patients, 40% had AR (3% trivial, 28% mild, and 9% moderate) at initial echocardiographic examination and 58% had AR (13 % trivial, 25% mild, 16% moderate, and 4% severe) after a mean period of 4.2 years. At initial echocardiographic examination, AR was present in 29,47, and 48% of patients with very mild, mild, and moderate severe aortic stenosis, respectively. After a mean period of 4.2 years, AR was detected in 40, 68, and 70% of patients with very mild, mild and moderate stenosis, respectively. AR appeared in 9% of patients with very mild stenosis, in 21% of patients with mild stenosis, and in 22% of patients with moderate aortic stenosis during follow-up period. Cardiac catheterization Twenty-Five patients underwent cardiac catheterization. Doppler PSIG (75 ± 16 mmHg) was higher than catheterization peak systolic gradient (47 ± 16 mmHg) (p < 0.0001). There was no statistically significant difference between estimated Doppler mean gradient (45 ± 9 mmHg) and catheterization peak systolic gradient (p = 0.50).
Table 2 Severity of aortic valvular stenosis according to age at initial echocardiographic examination Aortic stenosis at initial echocardiographic examination Age
Very mild, n (%)
Mild, n (%)
Moderate, n (%)
Severe, n (%)
Total, n (%)
< 1 month 1 month–1 year 1.1–5 years 5.1–10 years >10 years Total
7 12 27 31 13 90
10 15 22 29 11 87
5 14 14 20 11 64
7 12 3 9 6 37
29 53 66 89 41 278
(24) (23) (41) (35) (32) (33)
(35) (28) (33) (33) (27) (31)
(17) (26) (21) (22) (27) (23)
(24) (23) (5) (10) (14) (13)
(100) (100) (100) (100) (100) (100)
Table 3 Degree of aortic regurgitation according to the severity of aortic valvular stenosis at initial echocardiographic examination Initial aortic regurgitation Initial aortic stenosis
No, n (%)
Trivial, n (%)
Mild, n (%)
Moderate, n (%)
Severe, n (%)
Total n (%)
Very mild Mild Moderate Severe Total
61 47 37 19 164
2 4 2 4 12
22 28 16 8 74
5 8 8 4 25
0 0 1 2 3
90 87 64 37 278
(68) (54) (58) (51) (59)
(2) (5) (3) (11) (4)
(24) (32) (25) (22) (27)
(6) (9) (12) (11) (9)
(0) (0) (2) (5) (1)
(100) (100) (100) (100) (100)
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Table 4 Course of aortic valvular stenosis Aortic stenosis at follow-up
Very mild Mild Moderate Severe Total
Initial aortic stenosis, n
Very mild, n (%)
Mild, n (%)
Moderate, n (%)
Severe, n (%)
Follow-up (years),
72 70 44 6 192
55 6 0 0 61
14 38 5 2 59
2 20 23 0 45
1 6 16 4 27
(14)
3.7 5 3.7 1.2 4.2
Total, n (%)
Follow-up (years)
(76) (9) (0) (32)
(20) (54) (11) (31)
(3) (28) (53) (23)
(1) (9) (36)
± ± ± ± ±
2.9 3.5 3.5 2.8 3.8
Table 5 Course of aortic regurgitation according to the severity of aortic valvular stenosis Aortic regurgitation at initial and follow-up Initial aortic stenosis No, n (%) Very mild Initial AR Follow-up AR Mild Initial AR Follow-up AR Moderate Initial AR Follow-up AR Severe Initial AR Follow-up AR Total Initial AR Follow-up AR
Trivial, n (%)
Mild, n (%)
Moderate, n (%)
Severe, n (%)
51 (71) 43 (60)
1 (1) 7 (10)
17 (24) 13 (18)
3 (4) 9 (12)
0 (0) 0 (0)
72 (100) 72 (100)
3.7 ± 2.9
37 (53) 22 (32)
3 (4) 10 (14)
22 (32) 22 (32)
8 (11) 13 (18)
0 (0) 3 (4)
70 (100) 70 (100)
5 ± 3.5
23 (52) 13 (30)
2 (5) 7 (16)
14 (32) 13 (30)
5(11) 8 (18)
0 (0) 3 (6)
44 (100) 44 (100)
3.7 ± 3.5
5 2 116 (60) 80 (42)
0 1 6 (3) 25 (13)
0 1 53 (28) 49 (25)
1 1 17 (9) 31 (16)
0 1 0 (0) 7 (4)
6 6 192 (100) 192 (100)
1.2 ± 2.8
4.2 ± 3.8
AR, aortic regurgitation
Intervention Thirty-eight patients (17 after initial echocardiographic examination and 21 in follow-up) had an intervention: 29 had aortic valvotomy, 7 underwent Ross operation, 2 underwent aortic valve replacement, and 8 had balloon aortic valvuloplasty.
Discussion In accordance with previous studies [6, 8, 9], our study has shown that congenital AVS is frequently a progressive disorder. Our retrospective study showed that not only aortic stenosis but also AR progresses in time. The degree of obstruction remained stable in most of the patients with very mild stenosis. In 20% of these patients, the stenosis progressed to mild, and only one patient developed a severe stenosis after a mean period of 3.7 years. Cardiac evaluation may be carried out every 1 or 2 years in these patients. Aortic stenosis progressed to moderate in 37%, and moderate AR developed in 18% of the patients with
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mild aortic stenosis after a mean period of 5 years. Cardiac examination once a year seems reasonable in these patients. Nearly one-third of the patients with moderate stenosis progressed to severe stenosis, and severe AR developed in 3 of 44 patients after a mean period of 3.7 years. It is known that patients with severe aortic stenosis and severe AR are at increased risk of sudden death and serious ventricular arrhythmia [6, 8]. Therefore, we recommend, that patients with moderate aortic stenosis have a cardiac evaluation every 6 months. Similar to other reports [6, 8, 9, 17], congenital AVS affects males more commonly than females, and stenosis in patients younger than 2 years was more severe than in older patients in our study. Our younger patients had higher initial gradients than those observed at an older age. Therefore we recommend that children younger than 2 years old should undergo cardiac evaluation more frequently than older children according to the degree of the aortic stenosis. At initial echocardiographic examination, AR was detected in nearly one-third of patients with very mild stenosis and in nearly half of patients with mild or
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moderate aortic stenosis. Aortic regurgitation appeared in nearly 10% of patients with very mild stenosis after a mean period of 3.7 years and in nearly 20% of patients with mild or moderate aortic stenosis after a mean period of 5 and 3.7 years, respectively. Severe AR developed in only 7 patients (4%) and severe aortic stenosis developed in 27 patients (14%). None of the patients required an intervention due to AR. Bicuspid aortic valve (BAV) is frequently found underlying aortic stenosis in pediatric patients, 70–85% of stenotic aortic valves are bicuspid [15], and at least 50% of adults with AVS have BAV [26]. In our study, nearly half of the patients had BAV, similar to data on adult patients [26]. Stenosis in patients with BAV can be expected to progress more rapidly than that in patients with tricuspid aortic valve. The mean age and Doppler PSIG of our patients with bicuspid valve and tricuspid valve at diagnosis were similar. Because of different follow-up times, we could not determine the rate of progression of the aortic stenosis. In children with aortic stenosis, the peak-to-peak pressure gradient measured at cardiac catheterization is usually a reliable indicator of the severity of the obstruction and the need for intervention [5]. The most widely used noninvasive technique for estimating the severity of aortic stenosis is measurement of PSIG with Doppler echocardiography. Exact recommendations for the classification of severity of aortic stenosis based on Doppler gradients vary from center to center [7, 9, 11, 14]. Kiraly et al. [9] classified the severity of congenital aortic valvular stenosis into four grades according to PSIGs, considering the stenosis to be mild if the gradient was below 21 mmHg, moderate when between 21 and 50 mmHg, severe between 51 and 80 mmHg, and critical if higher than 80 mmHg. In several studies [7, 14], the severity of aortic valvular stenosis was classified according to peak and mean Doppler gradient measurements. The stenosis was considered to be severe if the peak Doppler gradient was more than 70 mmHg or the mean gradient was higher than 40 mmHg. If the maximum gradient was between 50 and 70 mmHg or the mean gradient was between 25 and 40 mmHg, the stenosis was considered moderate. If the maximum gradient was less than 50 mmHg and the mean gradient was less than 25 mmHg, the stenosis was considered mild. In the current study, the severity of aortic stenosis was graded according to Doppler PSIG measurements, similar the previously discussed reports [7, 11, 14]. Despite generally good correlation, Doppler-derived PSIGs are known to overestimate catheter-measured gradients [1, 3, 4, 10, 12, 13]. The Doppler mean gradient is another noninvasive mea-
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surement that has proven useful in the evaluation of patients with aortic stenosis [1, 3, 4, 10, 12, 13]. Bengur et al. [4], in a clinical study of AVS in children, suggested that a Doppler mean gradient greater than 27 mmHg identifies children with a peak-to-peak gradient at catheterization of 75 mmHg or greater, whereas a mean gradient less than 17 mmHg correlates with a catheterization-derived peak gradient of less than 50 mmHg. However, for patients with Doppler mean gradient between 17 and 27 mmHg, the gradient alone was insufficient for clinical decision-making. In a clinical study of congenital aortic valve stenosis, the Doppler mean systolic gradient correlated well with the catheter peak-to-peak gradient at low gradients and underestimated higher catheter gradients but agreed well at all levels with the catheter mean gradient. In adults, estimated Doppler mean gradient (2.4 · maximum velocity2), is recommended for following patients with AVS [23]. In our retrospective study, Doppler mean gradient was not available for all patients. Estimated Doppler mean gradients and catheter-measured gradients of our patients were similar, whereas PSIGs were higher than catheterization systolic pressure gradients. Estimated Doppler mean gradient is very useful in predicting the need for intervention in children with AVS. In patients with aortic stenosis, the pressure gradient is affected not only by the severity of the aortic stenosis but also by the amount of transvalvular flow [1, 3, 10, 12, 13]. Children with aortic stenosis, unlike adults, do not usually have diminished or increased stroke volume; therefore, the pressure gradient can be used to predict accurately the degree of aortic stenosis. In this study, patients with abnormal ventricular function were excluded. In addition, our patients were studied in a restring state, and agitated or restless children were sedated. Although aortic angiography has traditionally been used to semiquantitate the degree of AR, its invasive nature makes it impractical for frequent serial evaluations. All of the Doppler techniques are sensitive and reliable for the qualitative diagnosis of AR. Numerous efforts have been made to quantitate the degree of AR, but all have limitations. The best approach is to use as many Doppler measurements as possible to improve the reliability of the examination. Noninvasive quantification of AR is frequently performed with color-flow mapping techniques [2, 16, 18, 20]. Typical, this evaluation is based on color jet variables, such as jet length, width, or area. Omoto et al. [18] and Miyatake et al. [16] found a fair association between angiographic and color Doppler estimates of the severity of AR using the maximal distance
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to which the regurgitant jet extended in the left ventricle in the long a axis view as their criterion for severity. An in vitro study [24] using color Doppler and laser Doppler measurements of the flow disturbance caused by creating AR in an in vitro model suggested that regurgitant jet length and area are influenced by loading conditions and regurgitant volume. Color jet area and width have been found to correlate with angiography, but these variables may be affected by such factors as orifice shape, jet eccentricity, and left ventricular chamber constraints [2, 20]. In addition, measurements of color-flow variables may be influenced by instrument settings, such as pulse repetition frequency, transducer frequency, and gain, particularly at extremes of sampling depth [2, 16, 18, 20]. Spatial mapping of the regurgitant jet by pulsed wave estimates the severity of AR on the basis of the extent of the Doppler-detected signals within the left ventricular cavity [22]. Other pulsed- and continuous-wave Doppler studies have shown that the slope of the AR continuous-wave Doppler signal, the ratio of reverse to forward velocity time integrals in the aorta, and pulsed Doppler evidence of diastolic flow reversal downstream in the aorta all correlate with the severity of AR [19, 22, 27, 29]. Detection and assessment of severity of AR by pulsed- and continuous-wave Doppler techniques requires a lengthy period of examination and high degree of expertise to approximate the sensitivity and specificity of angiography. This is a major limitation of this modality. On the other hand, color Doppler is less time-consuming and more reproducible. In the current study, a semiquantitative estimate of the severity of AR was made by using color-flow and pulsed-wave Doppler echocardiography. Our patients did not have associated cardiac defects that contributed to left ventricular volume overload and abnormal ventricular function. In addition, our patients were studied in a resting state. In this study, the instrument settings for gain, width, sector angle, and ultrasound equipment were not identical. Because this study is retrospective, standardization of these parameters was impossible. The availability of optimal images led us to establish the adequate instrument setting for the individual studies.
Conclusions Patients with very mild stenosis may be followed with a noninvasive approach every 1 or 2 years, and an annual follow-up is suggested for patients with mild stenosis. Nearly one-third of patients with moderate stenosis at initial echocardiographic examination had severe stenosis after the following period. Therefore, we
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recommend that patients with moderate stenosis undergo noninvasive evaluation every 6 months. It seems that aortic stenosis is more problematic than AR in children with congenital AVS. Doppler estimated mean gradient is very useful in predicting the need for intervention in children with AVS. Acknowledgement This work was supported by Research Fund of Istanbul University grant UDP-612/02082005.
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