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Ann Thorac Surg 2003;75:1763-1768
© 2003 The Society of Thoracic Surgeons

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Original article: cardiovascular

Discrete subaortic stenosis: incidence, morphology and surgical impact of associated subaortic anomalies

^a Laboratory of Interventional Cardiology, Department of Pediatric Cardiology and Cardiovascular Surgery, Giannina Gaslini Institute, Children’s Hospital, Genova, Italy
^b Division of Cardiovascular Surgery, Department of Pediatric Cardiology and Cardiovascular Surgery, Giannina Gaslini Institute, Children’s Hospital, Genova, Italy
^c Intensive Care Unit, Department of Pediatric Cardiology and Cardiovascular Surgery, Giannina Gaslini Institute, Children’s Hospital, Genova, Italy

Accepted for publication December 17, 2002.

^* Address reprint requests to Dr Marasini, Laboratory of Interventional Cardiology, Giannina Gaslini Institute, Largo Gerolamo Gaslini, 5-16148 Genova, Italy.
e-mail: mauriziomarasini{at}istituto-gaslini.ge.it

	Abstract

Top Abstract Introduction Patients and methods Results Comment References

 
BACKGROUND: The association between discrete subaortic stenosis and other subaortic anomalies is a well known but rarely reported occurrence. The aim of this study is to define the incidence, morphology, and surgical impact of associated anomalies of the left ventricular outflow tract in children operated on for discrete subaortic stenosis.

METHODS: Between 1994 and 2000, 45 consecutive children were operated on for discrete subaortic stenosis. Patients were divided in two groups according to the obstructive lesion detected by echocardiography.

RESULTS: A localized shelf was found as an isolated lesion in 31 patients (group A), whereas additional subaortic anomalies were found in 14 cases (31%) and were multiple in 5 cases (group B). The anomalies included anomalous septal insertion of mitral valve (7 cases); accessory mitral valve tissue (2 cases); anomalous papillary muscle (2 cases); anomalous muscular band (8 cases); and muscularization of the anterior mitral valve leaflet (1 case). Cardiopulmonary bypass and aortic cross-clamping times were significantly shorter in group A. There were no operative deaths nor major complications or deaths during follow-up. A gradient of 15 mm Hg or more was found at follow-up in 5 cases whereas aortic regurgitation was estimated to be not clinically significant in all but 1 patient. Six cases of recurrent subaortic stenosis were found in our series, 3 of them with other subaortic anomalies.

CONCLUSIONS: This study shows that discrete subaortic stenosis can often be associated with other subaortic abnormalities. Surgical treatment of these anomalies produces excellent early and mid-term relief of obstruction without any increase in mortality and morbidity.

	Introduction

Top Abstract Introduction Patients and methods Results Comment References

 
Discrete subaortic stenosis remains a surgical challenge for the relatively high incidence of recurrence of stenosis or progression of aortic regurgitation [1, 2]. Recent reports suggest that surgery must be aimed at the removal of all structures causing flow turbulence in the left ventricular outflow tract (LVOT) in order to reduce the incidence of these complications [3–6]. We reviewed our experience to evaluate the incidence, morphology, and impact of LVOT associated anomalies on the surgical treatment and early outcome of patients operated on for discrete subaortic stenosis.

	Patients and methods

Top Abstract Introduction Patients and methods Results Comment References

 
From January 1994 through December 2000, 45 consecutive patients (26 male and 19 female) underwent surgery for discrete subaortic stenosis defined as a localized shelf of fibrous or fibromuscular tissue beneath the aortic valve [1, 7]. Patients with long segment stenosis, hypertrophic obstructive cardiomyopathy, or associated major anomalies such as transposition of the great arteries, univentricular heart, or double outlet right ventricle were excluded. Patients having previous cardiac surgery for ventricular septal defect (VSD) or atrioventricular septal defect (AVSD) and developing subaortic stenosis were included in the study as well as those with recurrent discrete subaortic stenosis. Preoperative and postoperative assessment was performed by transthoracic and transesophageal ultrasonography examination alone (Sonos 2500 or 5500; Hewlett-Packard) in all cases. Six patients who had previous cardiac operations also underwent preoperative cardiac catheterization to rule out any residual defect.

Patients were placed into two groups according to preoperative echocardiographic evidence of an obstructive lesion: a localized shelf with moderate to severe septal hypertrophy was found as an isolated lesion in 31 patients (group A), whereas additional anomalies of the LVOT were found in 14 patients (31%), 5 of them with multiple lesions (group B). These anomalies included anomalous septal insertion of mitral valve (7 cases; Fig 1); accessory mitral valve tissue (2 cases; Fig 2); accessory papillary muscle (2 cases; Fig 3); anomalous muscular bands within the LVOT (8 cases; Fig 4); muscularization of the anterior mitral valve leaflet (1 case; Fig 5). Eight patients in both groups had undergone previous surgery (Table 1): 4 had repair of a partial or complete AVSD and 1 was operated on twice for subaortic stenosis and severe mitral valve regurgitation; 1 patient had closure of a perimembranous VSD; and 7 had aortic coarctation repair. Finally, reoperation was required in 4 patients for recurrent subaortic stenosis. Aortic valve was found bicuspid in 9 patients, 7 in group A and 2 in group B (Table 1).

View larger version (119K): [in this window] [in a new window]   Fig 1. Biplane transesophageal long axis view through the left ventricular outflow tract demonstrating multiple subaortic chordal attachment (arrows) of the anterior mitral valve leaflet to the interventricular septum.

View larger version (124K): [in this window] [in a new window]   Fig 2. Two dimensional transesophageal long axis view of the left ventricular outflow tract showing accessory mitral valve tissue (white arrow) below the subaortic membrane (black arrow).

View larger version (126K): [in this window] [in a new window]   Fig 3. Cross-sectional parasternal long axis echocardiographic view showing attachment of an accessory papillary muscle to the anterior leaflet of the mitral valve (arrow).

View larger version (117K): [in this window] [in a new window]   Fig 4. Cross-sectional apical long axis view of the left ventricle demonstrating an anomalous muscular band (arrow) from the anterolateral papillary muscle to the interventricular septum.

View larger version (132K): [in this window] [in a new window]   Fig 5. Parasternal short axis view of the left ventricular outflow tract showing an anomalous muscularization of the anterior mitral valve leaflet (arrows).

Operations were always performed with hypothermic cardiopulmonary bypass and myocardial protection was obtained by anterograde blood cardioplegia repeated at 20-minute intervals. The obstructive lesions were approached through an oblique aortotomy, which was extended to the noncoronary sinus. The surgical procedure included membranectomy and deep myectomy in all patients and additional resection of the associated anomalies in group B, consisting of transection of anomalous papillary muscle or muscular band and resection of accessory chordal attachment or valvular tissue. When necessary a prolapsed or redundant aortic cusp was repaired using a standard pledget-reinforced technique. Residual gradient and aortic valve competence after cardiopulmonary bypass were evaluated by direct pressure recording and transesophageal echocardiography. All patients were regularly followed up by echocardiography to evaluate residual or recurrent subaortic obstruction and aortic valve function. Recurrence of subaortic stenosis was defined as the new echocardiographic appearance of a previously undetected lesion causing subaortic flow acceleration. Left ventricular outflow tract peak flow velocity 1.8 m/s or less was considered within normal range and the estimated pressure gradient was set equal to zero [8]. The obstruction was considered significant when a Doppler mean pressure gradient of 15 mm Hg or more was recorded. A one-step increase in the degree of aortic valve regurgitation was considered a sign of worsened diastolic aortic valve function. Data are expressed as median, range, and mean ± standard deviation. Comparison of means and proportions for continuous variables were based on standard t test. For each of the analyses a p value of 0.05 or less was considered statistically significant.

	Results

Top Abstract Introduction Patients and methods Results Comment References

 
All the patients but 1 were symptom free. No significant difference in age at operation and in preoperative Doppler mean pressure gradient was found between the two groups (Table 2). Moderate to severe aortic regurgitation was present preoperatively in 5 patients of group A and in 3 patients of group B (Fig 6); in 3 of them cusp resuspension was performed at operation. Associated anomalies of the left ventricular outflow tract detected by preoperative ultrasonography examination were confirmed intraoperatively in all cases and treated at the first operation in all but 2 cases. In these 2 latter patients, both previously operated on for AVSD, anomalous septal insertion of the mitral valve leaflet was considered untreatable without mitral valve replacement. This procedure was performed 3 years later in 1 case for recurrent subaortic stenosis associated with persistent severe mitral valve regurgitation. In another 2 patients first undergoing only ridge resection and deep myectomy, a significant residual gradient at the end of cardiopulmonary bypass was recorded (Table 3). Intraoperative transesophageal echocardiography confirmed the complete excision of the subaortic ridge and suggested that residual obstruction was related to the persistence of an anomalous muscular band. Cardiopulmonary bypass was then restarted and the associated anomalies were removed, with disappearance of the subaortic gradient.

View larger version (29K): [in this window] [in a new window]   Fig 6. Preoperative (hatched bars) and postoperative (dotted bars) distribution of aortic valve regurgitation in 45 patients.

	Comment

Top Abstract Introduction Patients and methods Results Comment References

 
Discrete subaortic stenosis is a progressive and probably acquired cardiac abnormality in which the left ventricular outflow tract is obstructed by a subvalvular fibromuscular ring [7, 10]. This condition may occur as a primary defect or be associated with other congenital heart diseases [1, 2, 5, 7]. Similarly to previously reported series, we included in our study patients with discrete subaortic stenosis having previous surgery for VSD or AVSD but not patients with subaortic stenosis associated with univentricular heart, transposition of the great arteries, double outlet right ventricle, or Shone’s anomaly [3–5, 10, 11]. In these latter patients, subaortic obstruction is usually more complex and often requires other surgical procedures. Surgery is widely accepted as a reliable means to relieve obstruction and to prevent complications secondary to long-standing ventricular hypertrophy, aortic valve damage, or infective endocarditis [3, 5, 7, 11–13]. However, major concerns remain on the indications for and timing of intervention [7, 11–15]. Significant LVOT gradient before surgery is still recommended by most centers but more rapid intervention is advocated by others especially for infants and children [3, 5, 7, 13]. Almost all patients in our series were children and consequently we chose to treat patients with a mean pressure gradient of 25 mm Hg or more and, irrespective of LVOT gradient, patients with a new appearance of aortic regurgitation. Mean Doppler gradient was preferred to the instantaneous peak Doppler gradient because of better correlation with the invasive gradient, particularly for the lower values [8].

Surgical excision of the subaortic ridge with resection of underlying LVOT muscle can now be accomplished with a very low mortality rate and minimal complications [1–5]. However this apparently simple surgical issue was found to be associated with a relatively high incidence of gradient recurrence or progression of aortic regurgitation after surgery [1–5, 11, 12, 15]. Recent reports suggest that surgery must be aimed at removing all structures causing LVOT flow turbulence in order to reduce the incidence of these complications [3–6, 10, 16]. Therefore more aggressive surgical approaches have been proposed other than "simple" excision of the fibrous ring, including early operation before the appearance of severe left ventricle hypertrophy [5], extended and circumferential myectomy [3], and mobilization of the left and right fibrous trigones [4]. The association between discrete subaortic stenosis and other left ventricular outflow tract anomalies such as anomalous mitral valve insertion [17], accessory mitral valve tissue [18–20], abnormal mitral papillary muscle [21], anomalous muscular bands within the LVOT [22], and posterior displacement of the infundibular septum without VSD [23] is well known but has been only sporadically reported. In a personal communication, LeCompte referred to a more than 40% incidence of these anomalies in a series of 37 patients with discrete subaortic stenosis and more recently the same French group reported one or more valvular anomalies in 48% of 73 consecutive patients operated on for discrete subaortic stenosis [25]. This unusually high incidence of associated anomalies is similar to our experience in which 31% of patients with discrete subaortic stenosis had associated subaortic anomalies. In these patients all LVOT associated anomalies should be visualized preoperatively because it is very difficult for the surgeon to identify them in an open but relaxed and cardiopleged heart [3]. For this purpose echocardiography may be considered mandatory as it can precisely delineate LVOT obstruction through multiple scan planes in a beating heart [6, 13, 25]. However this analysis requires expertise because LVOT obstructive anomalies may remain unrecognized preoperatively when associated with a "typical" discrete subaortic stenosis [17].

In our experience we observed a high rate of these anomalies not only in patients with subaortic stenosis after partial or complete AVSD repair, as previously reported in the literature [24], but also in patients with "isolated" discrete subaortic stenosis. Although echocardiography resulted as extremely accurate in recognizing the morphologic appearance of all associated anomalies, we were unable to understand and demonstrate preoperatively which obstruction component was due to discrete subaortic stenosis and which was ascribable to other associated anomalies. This aspect should be mainly related to the close proximity of all these structures. However in the 4 patients in which all the associated anomalies were not removed at the first operation, a residual gradient was recorded at the end of cardiopulmonary bypass. Moreover 3 of 6 cases of our series with discrete subaortic stenosis recurrence had other anomalies of the LVOT either undetected or not corrected at operation. Surgical resection of these abnormal structures was finally possible at the first operation in all but 2 cases without increased risk of early mortality and morbidity, notwithstanding a significant increase in cardiopulmonary bypass and aortic cross clamping mean times.

We have no experience of mitral valve regurgitation related to the resection of LVOT obstructive anomalies despite the frequent involvement of this valve in subaortic obstruction. In 2 patients, both previously operated on for AVSD, associated subaortic anomalies were considered untreatable without mitral valve replacement; in 1 of them a prosthetic valve was implanted because of persistent severe mitral valve regurgitation and subaortic stenosis and the other patient is waiting for operation. Limited follow-up time and a small number of patients characterize our experience, and further studies are required to conclude that recognition and surgical treatment of associated anomalies of LVOT may reduce the incidence of discrete subaortic stenosis recurrence and the progression of aortic regurgitation [12]. However our data support that discrete subaortic stenosis can often be associated with other abnormalities of LVOT and that their echocardiographic recognition is mandatory before operation. Surgical treatment of these anomalies produces an excellent early and mid-term relief of obstruction without any increase in mortality and morbidity. We suggest that, for patients operated on for "isolated" discrete subaortic stenosis, all associated anomalies that can play a role in LVOT obstruction should be treated immediately provided their surgical treatment does not require mitral or aortic valve replacement.

	References

Top Abstract Introduction Patients and methods Results Comment References

 

1. Rohlicek C.V., Font del Pino S., Hosking M., Miro J., Cote J.M., Finley J. Natural history and surgical outcomes for isolated discrete subaortic stenosis in children. Heart 1999;82:708-713.[Abstract/Free Full Text]
2. Serraf A., Zoghby J., Lacour-Gayet F., et al. Surgical treatment of subaortic stenosis: a seventeen-year experience. J Thorac Cardiovasc Surg 1999;117:669-678.[Abstract/Free Full Text]
3. Parry A.J., Kovalchin J.P., Suda K., et al. Resection of subaortic stenosis; can a more aggressive approach be justified?. Eur J Cardiothorac Surg 1999;5:631-638.
4. Yacoub M., Onuzo O., Riedel B., Radley-Scott R. Mobilization of the left and right fibrous trigones for relief of severe left ventricular outflow obstruction. J Thorac Cardiovasc Surg 1999;117:126-133.[Abstract/Free Full Text]
5. Brauer R., Laks H., Drinkwater D.C., Shvarts O., Eghbali K., Galindo A. Benefits of early surgical repair in fixed subaortic stenosis. J Am Coll Cardiol 1997;7:1835-1842.
6. Sigfusson G., Tacy T.A., VanAuker M.D., Cape E.G. Abnormalities of the left ventricular outflow tract associated with discrete subaortic stenosis in children: an echocardiographic study. J Am Coll Cardiol 1997;30:255-259.[Abstract]
7. Kitchiner D. Subaortic stenosis: still more questions than answers. Heart 1999;82:647-648.[Free Full Text]
8. Bengur A.R., Snider A.R., Serwer G.A., et al. Usefulness of the Doppler mean gradient in evaluation of children with aortic valve stenosis and comparison to gradient at catheterisation. Am J Cardiol 1989;64:756-761.[Medline]
9. Perry G.J., Helmcke F., Nanda N.C., Byard C., Soto B. Evaluation of aortic insufficiency by Doppler color flow mapping. J Am Coll Cardiol 1987;9:952-959.[Abstract]
10. Lampros T.D., Cobanoglu A. Discrete subaortic stenosis: an acquired heart disease. Eur J Cardiothorac Surg 1998;14:296-303.
11. Coleman D.M., Smallhorn J.F., McCrindle B.W., Willimas W.G., Freedom R.M. Postoperative follow-up of fibromuscular subaortic stenosis. J Am Coll Cardiol 1994;15:1558-1564.
12. Freedom R.M. The long and the short of it: some thoughts about the fixed forms of left ventricular outflow tract obstruction. J Am Coll Cardiol 1997;30:1843-1846.[Medline]
13. Pierli C., Marino B., Picardo S., Corno A., Pasquini L., Marcelletti C. Discrete subaortic stenosis. Surgery in children based on two-dimensional and Doppler echocardiography. Chest 1989;96:325-328.[Abstract/Free Full Text]
14. Oliver J.M., Gonzalez A., Gallego P., Sanchez-Recalde A., Benito F., Mesa J.M. Discrete subaortic stenosis in adults: increased prevalence and slow rate of progressions of the obstruction and aortic regurgitation. J Am Coll Cardiol 2001;38:835-842.[Abstract/Free Full Text]
15. Gersony W.M. Natural history of discrete subaortic subvalvular aortic stensosis: management implications. J Am Coll Cardiol 2001;38:843-845.[Free Full Text]
16. Cape E.G., VanAuker M.D., Sigfusson G., Tacy T.A., del Nido P.J. Potential role of mechanical stress in the etiology of pediatric heart disease: septal shear stress in subaortic stenosis. J Am Coll Cardiol 1997;30:247-254.[Abstract]
17. Haartyanszky I., Kadar K., Bojeldein S., Bodor G. Mitral valve anomalies obstructing left ventricular outflow. Eur J Cardiothorac Surg 1997;62:504-506.
18. Meyer-Hetling K., Alexi-Meskishvilli V.V., Dahnert I. Critical subaortic stenosis in a newborn caused by accessory mitral valve tissue. Ann Thorac Surg 2000;69:1934-1937.[Abstract/Free Full Text]
19. Schmid A.C., Zund G., Vogt P., Turina M. Congenital subaortic stenosis by accessory mitral valve tissue, recognition and management. Eur J Cardiothorac Surg 1999;15:542-544.
20. Calabro R, Santoro G, Pisacane C, et al. Left ventricular outflow tract obstruction due to mitral valve anomaly. Ann Thorac Surg 2001;72:1762
21. Imoto Y., Kado H., Yasuda H., Tominaga R., Yasui H. Subaortic stenosis caused by anomalous papillary muscle of the mitral valve. Ann Thorac Surg 1996;62:1858-1860.[Abstract/Free Full Text]
22. Moulaert A.J., Oppenheimer-Dekker A. Anterolateral muscle bandle of the left ventricle, bulboventricular flange and subaortic stenosis. Am J Cardiol 1976;37:78-81.[Medline]
23. Ozkutlu S., Tokel N.K., Saraçlar M., Alehan D., Yurdakul Y., Ruacan S. Posterior deviation of the left ventricular outflow tract without ventricular septal defect. Heart 1997;77:242-246.[Abstract/Free Full Text]
24. Gurbuz A.T., Novick W.M., Pierce C.A., Watson D.C. Left ventricular outflow tract obstruction after partial atrioventricular septal defect repair. Ann Thorac Surg 1999;68:1723-1726.[Abstract/Free Full Text]
25. Cohen L., Bennani R., Hulin S., et al. Mitral valvular anomalies and discrete subaortic stenosis. Cardiol Young 2002;12:138-146.[Medline]

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