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Ann Thorac Surg 2000;69:S118-S131
© 2000 The Society of Thoracic Surgeons
a Department of Cardiothoracic Surgery, Mount Sinai Medical Center, New York, New York, USA
Address reprint requests to Dr Nguyen, Dept of Cardiothoracic Surgery, Mount Sinai Medical Center, One Gustave L. Levy Pl, New York, NY 10029-6574
e-mail: khanhnguyen{at}mountsinai.org
Presented at the International Nomenclature and Database Conferences for Pediatric Cardiac Surgery, 1998–1999.
Abstract
The extant nomenclature for aortic valve disease is reviewed for the purpose of establishing a unified reporting system. The subject was debated and reviewed by members of the STS-Congenital Heart Surgery Database Committee and representatives from the European Association for Cardiothoracic Surgery. All efforts were made to include all relevant nomenclature categories using synonyms where appropriate. Aortic valve disease has been subdivided into stenotic and regurgitant lesions. Stenotic lesions have been characterized by anatomic location: supravalvar, valvar, and subvalvar. Regurgitant lesions have been characterized as either congenital or acquired. A comprehensive database set is presented that is based on a hierarchical scheme. Data are entered at various levels of complexity and detail that can be determined by the clinician. These data can lay the foundation for comprehensive risk stratification analyses. A minimum database set is also presented that will allow for data sharing and would lend itself to basic interpretation of trends. Outcome tables relating diagnoses, procedures, and various risk factors are presented.
I. Background
Aortic stenosis is an obstruction of the left ventricle outflow tract. It has an incidence of 0.03 to 0.34 per 1000 live births and constitutes about 7% of all congenital cardiac malformations [1–5]. In the fifth week of embryological development, the outline of the aortic valve at the apex of the aortic vestibule becomes more demarcated as a result of absorption of the excess mesenchymatous tissue [6]. By the eighth week, the aortic valve cusps and sinuses are well formed. The failure of any of the developmental steps leads to isolated or combined malformation of the aortic valve and the left ventricular outflow tract. The theory of hemodynamic molding postulates that the failure of development of cardiac structures is caused by diminished blood volume passing through them [7]. In fact, restrictive foramen ovale, hypoplastic left ventricle, and abnormal mitral valve are often seen in association with aortic coarctation or interruption. Keith, in 1924, attributed discrete aortic stenosis to incomplete atrophy of bulbus cordis [8]. Van Praagh and associates suggested that maldevelopment of the endocardial cushion tissue that forms the anterior leaflet of the mitral valve may result in discrete subaortic stenosis [9].
Extant nomenclature
Congenital aortic stenosis can be seen in three forms: supravalvar, valvar, and subvalvar [1, 5, 10]. The term "valvular" probably should be used to indicate valve cusps or folds in veins, lymphatic channels, or in the gastrointestinal tract [11]. Several types of congenitally abnormal valves have been described by Edwards [12, 13] and Roberts [14]. Most frequently seen is the bicuspid aortic valve with the two commissures arranged as anterior and posterior or left and right. There may be a third raphe or false commissure. The congenital neonatal critical stenosis belongs to a subgroup of congenital valvar stenosis that is of high risk. Edwards has suggested that unicuspid valves are stenotic from birth and are most commonly found in infants with critical aortic stenosis [12]. There may be complete fusion of commissure versus lack of commissure that results in a dome-shaped valve with a pinpoint opening. This valve has been referred to as acommissural to distinguish it from the unicommissural valve [15]. The unicommissural valve usually has an eccentric orifice and one defined commissure [16]. Most frequently, two raphes can be seen radiating from the ostium, indicating underdeveloped commissures of a tricuspid aortic valve [17]. Bicuspid aortic valve has two different leaflet orientations [14]. The leaflets are arranged either in a left-right orientation with the coronary arteries arising from each sinus or in anterior-posterior position in which both coronary arteries come from the anterior sinus. The bicuspid aortic valve leaflets can be equal in size or discrepant, and the larger leaflet may be prolapsing.
The dysplastic tricuspid aortic valve may have a gelatinous appearance and thick leaflets. The commissures are present but obscured by malformed leaflets. It is believed that swollen leaflets, rather than fusion of commissures, cause the obstruction [16]. Tricuspid aortic leaflets are rarely equal in size [18]. Abnormal tricuspid aortic valves may not be obstructive during early infancy but may become stenotic later in life due to leaflet thickening and calcification.
Patients with congenital valvar aortic stenosis can be categorized as mild, moderate, or severe by a combination of clinical, echocardiographic, and angiographic findings [19]. Patients with normal second heart sound, pulse volume, and contour fall into the mild aortic stenosis category. These patients have pressure gradient of less than 40 mm Hg and mean gradient of less than 20 mm Hg. The moderate stenosis group has an abnormally small pulse volume and a narrow inspiratory splitting of the second heart sound with a gradient up to 75 mm Hg and a mean gradient of 50 mm Hg. Those patients with severe stenosis have a single second heart sound or reverse splitting, abnormal pulse volume and contour, and a gradient greater than 75 mm Hg.
Subvalvar obstruction can be caused by different lesions: subaortic membrane or tunnel, accessory mitral valve tissue, abnormal insertion of the mitral anterior leaflet to the ventricular septum, deviation of the outlet septum seen in coarctation of the aorta or interrupted aortic arch, or a restrictive bulboventricular foramen in single-ventricle complexes. In 1963, Shone and associates described a complex of subvalvar aortic stenosis in association with supravalvar mitral ring, parachute mitral valve, and coarctation of the aorta [20]. Subvalvar aortic stenosis has been traditionally categorized into two types: localized subvalvar aortic stenosis, which consists of fibrous or fibromuscular ridge, and diffuse tunnel subvalvar aortic stenosis [1]. The circumferential narrowing commences at the annular level and extends downward for 1 to 3 cm.
Idiopathic hypertrophic subaortic stenosis will be discussed briefly and included in the hierarchy level because its clinical presentation can be similar to the other forms of subvalvar aortic stenosis. Known also as hypertrophic obstructive cardiomyopathy, this condition is characterized by a primary hypertrophy of the myocardium [21]. The etiology is unknown and has been seen in familial settings. The obstructive form involves different degrees of dynamic subvalvar aortic obstruction from a thickened ventricular wall and anterior motion of mitral valve. Hierarchical nomenclature and therapeutic options for this disease entity are discussed in the manuscript on cardiomyopathy by Delius in this supplement.
Supravalvar aortic stenosis is the rarest type of aortic stenosis. The disease can be inherited as autosomal dominant trait or part of William’s syndrome in association with mental retardation, elfin facies, failure to thrive, and occasionally infantile hypercalcemia [22]. Supravalvar aortic stenosis is conventionally described as three forms: an hourglass deformity, a fibrous membrane, and a diffuse narrowing of the ascending aorta [13]. The disease process may involve the coronary artery ostia, and the aortic leaflets may be tethered. The coronary arteries can become tortuous and dilated due to elevated pressures and early atherosclerosis may ensue. The brachiocephalic vessels may be involved in the diffuse form.
The term "hypoplastic left heart syndrome" (HLHS) includes various obstructive anomalies that affect the left heart and the thoracic aorta [1]. These lesions include supravalvar, valvar, and subvalvar and annular aortic stenosis, mitral stenosis, supravalvar mitral ring, hypoplasia of the ascending aorta, coarctation of the aorta, interrupted aortic arch, left ventricular hypoplasia or hypertrophy, or endocardial fibroelastosis. These lesions can occur in various combinations, and the presence of one lesion may suggest coexistence of others. A classification system was devised on which therapy can be tailored [1]. The class I HLHS consists of isolated anomalies including aortic stenosis. The class II HLHS heart has two congenital anomalies. Two ventricular repairs are usually possible. Class III has more than two anomalies, or two with coexisting left ventricular or ascending aortic or aortic arch hypoplasia. Class IV has aortic atresia. Therapy for the latter two classes usually involves operations leading to orthoterminal correction (single-ventricle repair). There are, however, rare cases of sufficiently sized left ventricles that will allow biventricular repair (see manuscript on hypoplastic left heart syndrome by Tchervenkov in this supplement).
This section will not discuss aortic stenosis that is associated with other complex malformations such as conoventricular malalignment as seen in ventricular septal defects (VSDs) with interrupted aortic arch, complete transposition of the great arteries with VSD, double-outlet right ventricles, atrioventricular canal defects, restrictive bulboventricular foramen in single-ventricle hearts, ventricular inversion, accessory endocardial cushion tissue, or septal hypertrophy from glycogen storage disease, etc.
II. Analysis: a unified nomenclature system
Aortic stenosis (AS) analysis
AS hierarchy level 1
AS hierarchy level 1 definitions
AS hierarchy level 2
AS hierarchy level 2 definitions
AS hierarchy level 3
GUEST EDITORS’ NOTE: Sometimes, the difference between dynamic subaortic stenosis (hypertrophic cardiomyopathy, [HC]) and fixed subaortic stenosis (diffuse or subaortic tunnel) may be difficult to discern. HC is characterized by primary cardiac muscle disease manifested by asymmetric hypertrophy and histologic evidence of disorganized myocardial fibers. Synonyms include: idiopathic hypertrophic subaortic stenosis (IHSS), asymmetrical septal hypertrophy (ASH), and obstructive cardiomyopathy. HC is also characterized by dramatic left ventricular hypertrophy in the absence of any luminal dilatation. There is also asymmetric distribution of the hypertrophy with the septal thickness exceeding that of the free wall in 90% of cases. The mitral valve often exhibits a thickened anterior leaflet, which is attributed to contact with the septum. The obstruction to left ventricular ejection in HC has both a static and dynamic component. The asymmetrical hypertrophy impedes blood flow from the ventricular cavity to the aortic valve, which is usually normal. Also, the anterior leaflet of the mitral valve moves anteriorly during systole further obstructing ventricular ejection. This systolic anterior motion (SAM) of the mitral valve helps to distinguish this entity from the other forms of diffuse subaortic stenosis. HC is noted in this section to remind the clinician to enter the patient in the pediatric cardiomyopathy section of the database, where the clinical features, operative procedures, and postoperative outcomes will be considered in relation to other forms of cardiomyopathies.
AS hierarchy level 3 definitions
AS, valvar, congenital
Valvar AS from congenital valvar malformation and/or annular hypoplasia
AS, valvar, acquired
Valvar AS that is not present at birth, including valvar AS occurring as a consequence of malfunction or deterioration of an aortic prosthesis, valvar apparatus of neoaorta, or conduit
AS, supravalvar, diffuse
Diffuse narrowing of the ascending aorta and may extend distally beyond
AS, supravalvar, discrete
Localized narrowing with hourglass deformity of the ascending aorta and thickened aortic wall
AS, supravalvar, acquired
Narrowing of ascending aorta, neoaorta, or conduit
AS, subvalvar, fixed
An anatomic narrowing of tissue below the aortic valve which causes obstruction to flow. This narrowing can be caused by discrete lesions such as a subaortic membrane (subaortic shelf) or diffuse lesions such as a subaortic tunnel.
AS hierarchy level 4
Hierarchy level 4 definitions
AS, valvar, congenital, critical (infantile)
Critical AS in newborn that systemic perfusion depends on patent ductus arteriosus
AS, valvar, congenital, noncritical
AS diagnosed in childhood or later
AS, valvar, acquired, neoaorta
AS after construction of a neoaorta such as arterial switch or Ross operation
AS, valvar, acquired, rheumatic
AS as a result of rheumatic valvar disease
AS, valvar, acquired, prosthetic
AS secondary to prosthetic valve malfunction, from calcification of prosthetic leaflets or ingrowing of pannus
AS, valvar, acquired, conduit
AS from stenotic changes of conduit valvar apparatus
AS, supravalvar, acquired, neoaorta
Supravalvar AS after a neoaortic reconstruction such as arterial switch, Ross operation, or Norwood procedure, etc
AS, supravalvar, acquired, suture line
Supravalvar AS from a previous aortotomy or cannulation
AS, supravalvar, acquired, conduit
Supravalvar AS from a narrowed conduit
AS, subvalvar, diffuse (subaortic tunnel)
Circumferential tubular fibrous narrowing extends from below the aortic valve towards the body of the left ventricle
AS, subvalvar, discrete (subaortic membrane, subaortic shelf)
Obstruction caused by a subaortic membrane with or without a hypertrophic anterior septum
AS hierarchy level 5
Hierarchy level 5 definitions
AS, subvalvar, diffuse, involves outlet portion of LV
Diffuse subvalvar aortic stenosis, affecting 1 cm or more of the outflow tract
AS, subvalvar, diffuse, extends to the body of LV
The tunnel obstruction extends to the mid LV
AS, subvalvar, diffuse, extends to the apex of LV
The tunnel obstruction extends to the LV apex
AS, subvalvar, discrete, without hypertrophic anterior septum
Subvalvar obstruction caused by a subvalvar membrane and anterior septum is normal
AS, subvalvar, discrete, with hypertrophic anterior septum
Subvalvar obstruction caused by subaortic membrane and a hypertrophic septum that surgical relief requires removal of the membrane and septal myomectomy
Additional modifiers for AS hierarchy level 1
Additional modifiers for AS hierarchy level 2
III. Nomenclature for AS treatment options
AS treatment hierarchy level 1
AS treatment hierarchy level 2
AS treatment hierarchy level 3
AS treatment hierarchy level 4
Additional comments on treatment options
Extended valvuloplasty
involves freeing of leaflets, commissurotomy, and extension of aortic leaflets using autologous or bovine pericardium [23]
Patch aortoplasty
Simple patch: a diamond-shaped patch is used
Extended patch (Doty)
Y-shaped patch, incision is carried into two sinuses
Brom repair
Transection of ascending aorta, excision of fibrous ridge, and patching of three sinuses separately
Aortoventriculoplasty (Vouhé)
Aortoseptal approach for aortoventriculoplasty [24]. The aortic annulus is opened at the commissure of the left and right coronary cusps, and the incision is carried down to the septum and the right ventricular infundibulum. The septal muscle is resected; various incisions are then closed. The aortic annulus is reconstituted.
Modifiers on treatment options for AS hierarchy level 1
Modifiers on treatment options for AS hierarchy level 2
Additional comments on modifiers on treatment options for AS
Supravalvar repair
Coronary ostia are occasionally involved in the process and can be obstructed.
Annular enlargement, Manouguian
The aortotomy is carried to the tip of the commissure between the left and noncoronary sinuses, then down to the anterior leaflet of the mitral valve. A patch is then placed.
Annular enlargement, Nicks
The aortotomy is taken through the noncoronary sinus to the anterior leaflet of the mitral valve. The left atrium is opened in the process and patched.
Aortic regurgitation: extant nomenclature
Congenital aortic regurgitation is rare as an isolated entity [25]. Its incidence was reported at 0.3% of congenital heart disease from a series from The Hospital for Sick Children [26]. In fact, the most common cause of congenital aortic regurgitation is the aortic-left ventricular tunnel, which itself does not involve the aortic valve [27]. Historically, pediatric aortic regurgitation is more commonly seen with other associated cardiac anomalies. There are sporadic reports of congenital malformation of the aortic valve that result in aortic insufficiency shortly after birth from an absence or underdeveloped aortic valve cusp [28, 29]. Stenotic aortic valves may already have some degree of aortic regurgitation due to severe aortic leaflet abnormality.
Supravalvar AS may involve the aortic valve, which causes tethering or retraction of aortic valve leaflets. Similarly, subvalvar AS in the form of subaortic membrane may encroach on an aortic cusp, or the turbulence caused by stenotic jet can create progressive aortic regurgitation. Quadricuspid aortic valves, as a cause of severe aortic regurgitation, have also been reported in older patients whose diagnoses were made fortuitously [30, 31]. More commonly, aortic regurgitation is seen in stenotic congenital bicuspid aortic valves. The regurgitation can be mild or moderate, or may become severe as a sequelae of infective endocarditis. Without infection, the incidence of congenital bicuspid aortic valve regurgitation is 7% [32]. Aortic regurgitation, in association with a VSD, is well known. The incidence of aortic valve incompetence among patients with VSDs is estimated to be approximately 3% to 5% in the western hemisphere. The incidence is even higher in the East, where supracristal VSD is more common [33]. Acquired aortic insufficiency is seen as a result of rheumatic disease. It frequently occurs in combination with mitral valve disease. Isolated rheumatic aortic regurgitation was seen in 6% of patients with rheumatic heart disease [34]. Aortic regurgitation can be seen in postinterventional therapy such as balloon or surgical valvotomy or malfunction of a prosthetic valve or conduit. Aortic regurgitation can occur in patients with dilated aortic root from annuloectasia, infective endocarditis, virus arteritis, trauma, or autoimmune process such as relapsing chondritis, and Wegener’s granuloma.
The therapy for aortic regurgitation in pediatric regurgitation remains problematic. The available treatments provide palliation, but not a cure. There may be postponement of valve replacement in the children with the technique of extended aortic valvuloplasty [23]. The replacement of the valve provides temporary relief, but poses other medical problems that include infection, anticoagulation, and reoperation. In fact, most of the procedures we are performing today for congenital heart diseases are at best palliative [35].
Aortic regurgitation can be graded angiographically [36] or echocardiographically. The correlation between the two modes of measurement is good when used in adult patients, but less reliable in pediatric populations. In aortic regurgitation, Perry and colleagues [37] found that the width of the jet at its origin, relative to the width of the left ventricular outflow tract, correlates better with the angiographic findings.
There is no clear method of classification of pure congenital aortic regurgitation. Kawashima and colleagues proposed a classification of VSD with associated aortic regurgitation and pulmonary stenosis [38] based on anatomy. Because of diverse causes of aortic regurgitation in the pediatric population, classification of pediatric aortic regurgitation may have to be based on the primary disease process that leads to aortic regurgitation. It should take into account, as in valvar AS, the structural characteristic of the aortic root complex (Table 1).
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AR hierarchy level 1
AR hierarchy level 1 definitions
Aortic regurgitation
Definition: The reflux of blood from the ascending aorta into the left ventricle during diastole [5].
AR hierarchy level 2
AR hierarchy level 3
GUEST EDITORS’ NOTE: Aorticoventricular tunnel, while physiologically a form of congenital aortic regurgitation, is more accurately described as a form of congenital paravalvar aortic regurgitation. This distinction is sufficiently different as to require a separate category for aorticoventricular tunnel, which is discussed in a separate article by Myers in this supplement.
AR hierarchy level 3 definitions
AR, congenital, aorticoventricular tunnel
Abnormal communication that begins in the ascending aorta, bypasses the aortic valve, and terminates in the left ventricle (see manuscript on aorticoventricular tunnel in this supplement by Myers)
AR, acquired, trauma
AR from blunt or sharp injuries to the aortic valve, excluding those caused iatrogenically by balloon valvotomy or other procedure
AR hierarchy level 4
Additional comments on AR
AR, congenital, aortic valve malformation, valvar AS
Congenital AS is one of the common causes of congenital AR
AR, congenital, associated cardiac anomalies
AR found with associated cardiac anomalies
AR, congenital, aortic valve malformation, supravalvar AS
AR found with congenital supravalvar AS due to involvement of aortic valve leaflets
AR, acquired, associated cardiac anomalies, supravalvar AS
AR develops later due to progressive involvement of the aortic valve leaflets
Additional modifiers for aortic regurgitation hierarchy level 1
Additional modifiers for aortic regurgitation hierarchy level 2
AR treatment hierarchy level 1
AR treatment hierarchy level 2
AR treatment hierarchy level 3
Additional comments on modifiers for AR treatment options
Annuloplasty, partial
Aortic annulus is partially narrowed using either interrupted sutures or noncircumferential sutures
Annuloplasty, complete
Circumferential sutures are used
Modifiers on treatment options for AR hierarchy level 1
Modifiers on treatment options for AR hierarchy level 2
Additional comments on modifiers on treatment options for AR
Annular enlargement, Manouguian
The aortotomy is carried to the tip of the commissure between the left and noncoronary sinuses, then down to the anterior leaflet of the mitral valve. A patch is then placed.
Annular enlargement, Nicks
The aortotomy is taken through the noncoronary sinus to the anterior leaflet of the mitral valve. The left atrium is opened in the process and patched.
IV. Diagnosis and procedure short lists
V. Potential diagnostic-related risk factors
Potential preoperative risk variables
Similar to preoperative risk variables in other congenital cardiac defects
Potential intraoperative risk variables
Similar to intraoperative risk variables in other congenital cardiac defects
Potential postoperative risk variables
Similar to postoperative risk variables in other congenital cardiac defects
Potential preoperative risk variables associated with AS
Critical AS
Hypoplastic LV
Hypoplastic annulus
Congenital mitral valve disease
Severe LV hypertrophy
Endocardial fibroelastosis
Associated cardiac anomalies [6]
Potential preoperative risk variables associated with subvalvar AS
Tunnel form
Potential preoperative risk variables associated with supraaortic stenosis
Diffuse form
VI. Database studies and outcome analysis
Data reports are applicable to each type of aortic stenosis and regurgitation
Type (by year): This table will show the number and percentage of each of the AS and AR type that were treated.
Age at operation
This table will show age distribution at time of surgery.
Weight at operation
This table will show patient’s weight at time of surgery.
Length of CPB
This table will show length of cardiopulmonary bypass time.
Cross-clamp time
This table will show length of cross-clamp time.
Duration of DHCA
This table will show duration of deep hypothermic circulatory arrest.
Type of cardioplegia
This table will show type of cardioplegia: blood versus crystalloid.
Preoperative ventilation
This table will show number and percentage of patients who were on ventilatory support preoperatively.
Preoperative inotropic support
This table will show number and percentage of patients who were on inotropic support preoperatively.
Preoperative hemodynamic support
This table will show number and percentage of patients who were on ventricular assist device or extracorporeal membrane oxygenation (ECMO) preop-eratively.
Postoperative hemodynamic support
This table will show number and percentage of patients who were placed on ventricular assist device or ECMO for hemodynamic support postoperatively.
Postoperative length of ventilation
This table will show the length of ventilation.
Intensive care unit (ICU) length of stay
This table will show ICU length of stay.
Intraoperative complication
This table will show number and percentage of patients who had intraoperative complications.
Postoperative complication, transient
This table will show number and percentage of patients who had transient postoperative complication.
Postoperative complication, permanent
This table will show number and percentage of patients who developed permanent postoperative complication.
Operative mortality
This table will show number and percentage of patients who died within 30 days after surgery.
Method of repair for each type
This table will show different methods employed for each type of AS and AR.
Repair versus replacement
This table will show number and percentage of patients who had repair versus replacement of the aortic valve.
Perioperative transfusion
This table will show number and percentage of patients who received transfusion of blood and blood products.
Length of ICU stay versus diagnosis
This table will show the length of ICU stay versus type of defect.
Length of ICU stay versus length of cardiopulmonary bypass (CPB)
This table will show the length of ICU stay versus length of CPB.
Length of ICU stay versus length of cross-clamp time
This table will show the length of ICU stay versus length of cross-clamp time.
Length of ICU stay versus length of DHCA
This table will show the length of ICU stay versus length of DHCA.
Length of ventilation versus length of CPB
This table will show the length of ventilation versus length of CPB.
Length of ventilation versus length of cross-clamp time
This table will show the length of ICU stay versus length of cross-clamp time.
Length of ventilation versus length of DHCA
This table will show the length of ICU stay versus length of DHCA.
References
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