Structure and anatomy of the aortic root
Cardiac Morphology Unit, National Heart and Lung Institute, Imperial College and Royal Brompton Hospital, Dovehouse Street, London SW3 6LY, UK
* Corresponding author. Tel: +44 207 3518751; fax: +44 207 3518230. E-mail address: yen.ho{at}imperial.ac.uk
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Abstract |
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 Top Abstract Structure and anatomy of...Location of the aortic...Anatomy of the aortic...Aortic sinuses and sinutubular...Aortic leafletsThe ventriculo-arterial junctionInterleaflet fibrous trianglesThe normal functional unitAbnormal/pathological variantsConclusionsFundingReferences |
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Aims: Understanding the anatomy of the aortic root is particularly relevant in the current era of evolving management strategies including percutaneous and transcatheter therapeutic techniques for valve or device implantations.
Methods and results: This review describes the aortic root as a composite structure of several elements, not only the valvar leaflets. The valvar leaflets have a unique shape with deep closure lines buttressed by the nodule of Arantius. The scalloped configuration of the hingelines of the leaflets crosses the ventriculo-arterial junction, leaving interleaflet fibrous triangles between the sinuses that are anatomically aortic but haemodynamically ventricular. The fibrous triangle between the right and the non-coronary leaflets is the guide to the location of the atrioventricular conduction bundle. The coronary orifices are located close to the level of the sinutubular junction. Variations in leaflet structure and their arrangements result in valvar stenosis or regurgitation, or both. Often, diseases of the aortic root involve more than one structural element.
Conclusion: The leaflets and their hingelines, aortic sinuses, interleaflets triangles sinutubular junction, and ventriculo-arterial junction and their structures adjoining the junctions should be taken into account when considering the aortic root. Owing to its central location, the aortic root is in close proximity to all the cardiac chambers, the atrial septum, ventricular septum and the atrioventricular conduction bundle.
Keywords: Aortic valve; Anatomy; Aortic stenosis; Aortic regurgitation; Bicuspid aortic valve; Intervention
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Structure and anatomy of the aortic root |
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TopAbstractStructure and anatomy of...Location of the aortic...Anatomy of the aortic...Aortic sinuses and sinutubular...Aortic leafletsThe ventriculo-arterial junctionInterleaflet fibrous trianglesThe normal functional unitAbnormal/pathological variantsConclusionsFundingReferences |
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The term ‘aortic root’ refers to the aortic valve from its position at the left ventricular outlet to its junction with the ascending portion of the aorta. Anatomically, this whole structure is the aortic valve. The normal aortic valve is more complex than its three semilunar leaflets suggests. According to Walmsley (1929),1 Henle was the first to introduce the term ‘arterial root’ to replace the term ‘arterial ring’ since, inherent in the semilunar attachments of the valvar leaflets, the morphological boundary of the valve does not correspond to the functional boundary (see below). To appreciate the anatomy of the aortic valve, it is necessary to examine its component parts and how they relate to each other so as to function as a unit. The valve comprises of the semilunar leaflets with attachments (or hingelines) to ventricular and aortic walls and the ‘anterior’ mitral leaflet, interleaflet triangles, aortic sinuses (of Valsalva), and the sinutubular junction. In describing the aortic root, it is necessary to review its location in relation to neighbouring structures for a better understanding of the diseases affecting the aortic root. But, first, there needs to be clarification of the nomenclature used for describing the aortic leaflets and their corresponding sinuses. In plan view, the aortic valve in closed position shows tri-radiating lines of apposition between adjacent leaflets reaching to the peripheral commissures, and encircled by the aortic wall (Figure 1A and B). The aortic root bulges outwards to form the three sinuses. Two of the aortic sinuses give rise to the main coronary arteries and the sinuses are termed right and left coronary sinuses. The third sinus is conveniently termed the non-coronary aortic sinus. In anatomic descriptions, however, the sinuses are named anterior (for right coronary), left posterior (for left coronary), and right posterior (for non-coronary). In attitudinal orientation, however, the sinuses are in anterior, left posterolateral, and right posterolateral positions respectively.2 In clinical vernacular, the terms commonly used are right coronary, left coronary, and posterior. Although ‘posterior’ may be useful in the normally structured heart, it is not at all useful when the aorta arises in an abnormal position, e.g. in hearts with complete transposition of the great arteries. In all hearts, irrespective of location of the aortic valve relative to the pulmonary valve, the sinuses that give origin to the coronary arteries are nearly always the aortic sinuses that are adjacent to the pulmonary valve. These are described as the ‘facing’ aortic sinuses. It is exceedingly rare to encounter origin of a coronary artery from the ‘non-facing’ aortic sinus.3,4 My preference is to use the term ‘non-coronary’ instead of ‘posterior’ in this review, although some may argue that when there is abnormal origin of both main coronary arteries from the same aortic sinus, or there is a single coronary artery, there will then be two non-coronary aortic sinuses!
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Location of the aortic root |
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When the heart is viewed in anterior–posterior projection, it is clear that the aortic root is the centrepiece of the heart. Although the pulmonary valve is the most superiorly situated cardiac valve lying behind the third costal cartilages, the aortic valve is adjacent but right and posterior to the pulmonary valve. The plane of the aortic valve tilts inferiorly at an angle to the pulmonary valve. The nadirs of the aortic sinuses lie in a plane at an angle of 30° from the horizontal.2 Thus, the arterial surface of the closed leaflets of the aortic valve is directed not only upwards but also rightward at an angle of at least 45° to the median plane.5 Within the normal aortic root are three bulging aortic sinuses of Valsalva. These lie within the pericardial sac. By virtue of its central location in the heart, the aortic root has a complex relationship to the cardiac chambers (Figure 1B). Rupture of a sinus of Valsalva aneurysm due to separation of the intima from the media can lead to a cardiac chamber or into the pericardial space. Rupture of the non-coronary aortic sinus can open into the right or left atrium while rupture of the left coronary aortic sinus can lead to the left atrium or the pericardial space. In majority of cases of ruptured aortic sinus, it is the right coronary aortic sinus that is involved and this can lead to the right atrium or the right ventricular outflow tract.6 The region of the aortic wall adjoining the right- and non-coronary aortic sinuses abut the anterior right atrial wall causing it to bulge into the atrial chamber. Within the right atrium, the bulge forms the aortic mound (or torus aorticus), and can give the false impression of being part of the atrial septum (Figure 1B). Cardiac interventionists should be aware of this anatomic relationship when performing transseptal puncture or implanting devices to close atrial septal defects or patent foramen ovale defects.
Guarding the left ventricular outflow tract, the aortic root also has an intimate relationship with the ventricular septum and the mitral valve (Figure 1C). In attitudinal orientation, it is apparent that the aortic root leans rightward slightly, over the ventricular septum, to overly the right ventricle. In the elderly, the relationship between septal crest and aortic root changes to give a sigmoid-shaped ventricular septum. This normal variation should be differentiated from hypertrophic cardiomyopathy.
The curvature of the ventricular septum forms the antero-superior wall of the left ventricular outflow tract and this continues smoothly into the left ventricular wall. The major portion of the septal component is muscular apart from its upper medial part which is the membranous septum of the heart. Adjoining the membranous septum is the fibrous half of the outflow tract that makes up the posterior wall. This is formed by the area of fibrous continuity between the aortic valve and the aortic (or anterior) leaflet of the mitral valve (see below) (Figure 1C). The mitral leaflet hangs like a curtain between the inflow and outflow tracts of the left ventricle (Figure 2).
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Anatomy of the aortic valve |
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Clinicians, especially surgeons, frequently speak of the aortic valve having an annulus or ring, as if there is a band-like circle of fibrous accretions. Anatomically, this is far from the case. Describing the arterial roots in Quain's Elements of Anatomy in 1929, Walmsley1 stated ‘at each of the arterial openings there is a short tubular zone formed of fibrous tissue, the proximal and distal borders of which, at its junctions with the ventricular muscle and with the typical arterial wall respectively, are uneven’. He continued by crediting Henle for drawing attention to ‘this difficulty of defining the ventriculo-arterial boundary’ and replacing the term ‘arterial ring’ with ‘arterial root’, although the source of Henle's works was not specified. McAlpine2 in 1975 again emphasized the lack of rings in all four cardiac valves. A footnote in his Atlas states: ‘Annulus, in Latin, designates a ring, i.e. a circle. In this work, the word is applied only to the fibrous attachments of aortic and pulmonary leaflets which, in reality, constitute only a segment, not of a circle, but of an ellipse. A search for a reasonable term has met with failure. The term annulus, used to designate four fibrous structures to which the four valves of the heart are attached, is, in my opinion, ill-founded–no such structures are to be found.’ Despite these assertions, controversies remain. In reviewing the aortic root, Berdajs et al.7 insist an annulus exists ‘at the border between the superior and basal third of the aortic root wall’ based both on macroscopic and microscopic examination.
Clearly, the aortic root is a complex structure that requires analysis part by part but always remembering that all the parts contribute to form one functional unit that is commonly referred to as the aortic valve.
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Aortic sinuses and sinutubular junction |
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The spaces between the luminal surface of the three bulges on the aortic root and their respective valvar leaflets are known as the aortic sinuses of Valsalva. Davies considered the wall of the aortic root the aortic sleeve, distinguishing it from the aortic wall on account of its histological composition.8 The sleeve is composed of fibrous tissue but its upper part bordering with the tubular aorta shows increase in elastic fibres which blend into the elastic tissue and smooth muscle in the media of the aortic wall without discrete histological demarcation. The superior border of the sinuses is the sinutubular junction (also known as the supra-aortic ridge) (Figures 1C and 2). On the outside, the sinutubular junction is where the tubular portion of the aorta joins onto the sinusal portion. Inside, there is usually a slightly raised ridge of thickened aortic wall. But, the sinutubular junction is not perfectly circular. It takes on the contour of the three sinuses, giving it a mildly trefoil or scalloped outline (Figure 1A).
Silver and Roberts studied 100 formalin-fixed hearts from adult patients with normally functioning aortic valves and found that the luminal area of the aorta at the sinutubular junction increased with age and with heart weight where increased heart weight was attributed to systemic hypertension.9 Volume-wise, the sinuses are largest when the valve closes, serving as reservoirs during ventricular diastole and allows filling of the coronary arteries. The right sinus is the largest as is its height, with the left sinus being the smallest on both counts.7,9 Thus, the plane of the sinutubular junction does not lie parallel to a plane joining the bases of the sinuses but has a tilt of 11º.10 On echocardiography, the diameter of the sinutubular junction is 
75% of the maximal sinus diameter.11
When left ventricular pressure exceeds that in the aortic root, the valvar leaflets are pushed apart and fall back into their respective sinuses, allowing unimpeded ejection of blood. The orifices of the coronary arteries are commonly found close to the level of the sinutubular junction (Figure 3A).12
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Aortic leaflets |
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Each of the three leaflets of the normal aortic valve has a free margin and a margin where it is attached in semilunar fashion to the aortic root. The maximal height of each leaflet is considerably less than that of its sinus on account of its scoop-shaped free margin (Figure 3A and B). When the valve opens, the leaflets fall back into their sinuses without the potential of occluding any coronary orifice. The semilunar hingelines of adjacent leaflets meet at the level of the sinutubular junction, forming the commissures. The body of the leaflets are pliable and thin in the young, although its thickness is not uniform. Each leaflet has a somewhat crimpled surface facing the aorta and a smoother surface facing the ventricle. The leaflet is slightly thicker towards its free margin. On its ventricular surface, is the zone of apposition, known as the lunule, occupying the full width along the free margin and spanning approximately one-third of the depth of the leaflet. This is where the leaflet meets the adjacent leaflets during valvar closure. At the midportion of the lunule, the ventricular surface is thickened to form the nodule (of Arantius) that extends along 60% of the inferior margin of the lunule (Figure 3A).2 With the valve is in closed position, the inferior margin of the lunules meet together, separating blood in the left ventricular cavity from blood in the aorta. Fenestrations in the lunules are common, especially in the elderly, but the valve remains competent because they are above the closure line. Larger fenestrations that extend beyond the zones of apposition, however, can lead to significant valvar regurgitation.
With age, the leaflets become thicker and stiffer. In their study comparing leaflet thickness in normal hearts from patients in three age groups, <20, 20–59, and 
60 years, Sahasakul et al.13 found increase in thickness at nodule, lunule, and middle of leaflet body with age that became more prominent after 50 years with the nodule becoming twice the thickness of the lunule. Sclerosis, dystrophic calcification, or commissural fusion can result in a stenotic valve.
According to Davies,8 the total area of the valvar leaflets is 40% greater than that of the aortic root. But, as noted by Roberts in 1970, the three leaflets are not perfectly equal in dimensions.14 Vollbergh and Becker found the right leaflet to be the largest, whereas, later, Silver and Roberts using planimetric measurements reported the non-coronary leaflet had the largest mean area and mean weight.9,15
On histology, each leaflet comprises of a fibrous core covered by subendothelial fibroelastic layers termed the arterialis (on the aortic surface) and the ventricularis (on the ventricular surface). The latter is thickest along the closing edges of the leaflet. The fibrous core has two components: the fibrosa and the spongiosa, bordered by the arterialis and the ventricularis, respectively. The fibrosa contains mainly collagen fibres with some elastin. The larger collagen bundles are aligned circumferentially, parallel to the free margin, adding to the undulations on the arterialis aspect. Radially aligned collagen fibres are found near to the hingeline. The collagen fibres are mainly type I, providing strength to the leaflet. The spongiosa comprises of loose connective tissue rich in proteoglycans and allows shearing between the adjacent layers. The ventricularis is thinner than the fibrosa and contains more elastin and less organized collagen fibres. At the lunule and the free margin of each leaflet, the ventricularis becomes thicker, especially at the nodule of Arantius where it is a mass of elastic tissue. It has been demonstrated in the pig valve that the ventricularis contains a considerable amount of sheet elastin, whereas the elastin in the fibrosa is arranged like tubular meshwork that extended circumferentially across the leaflet.16 On studying the mechanics of the aortic valve, Vesey17 commented that the elastin acts like a ‘housekeeper’ in restoring the collagen fibres back to their original state. The core of the leaflet is continuous with the fibrous wall of the aortic sleeve at the hingelines where the fibrous tissue is thickened. When the leaflets are detached from the wall, the semilunar hingelines appear like raised ridges (Figure 3C).
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The ventriculo-arterial junction |
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Unlike the ‘annulus’, the anatomic ventriculo-arterial junction is more reminiscent of a circle. It is where ventricular myocardium terminates and gives way to the wall of the aortic sleeve. But, on account of the region of aortic-mitral valvar continuity and the central fibrous body forming the remaining 60% or so of the ventriculo-arterial junction, the slightly larger portion of the junction is fibrous. Here, precise location of the junction is not possible and we can only extrapolate by completing the circle around the outflow tract, and making the assumption that there is a sharp line between myocardium and sleeve (Figure 3C). Nevertheless, the semilunar hingelines of the valvar leaflets create an intricate arrangement at this junction. The nadirs of the hingelines are locates below the ventriculo-arterial junction. Thus, where the hingelines cross muscle, myocardial segments are included into the aortic sinuses (Figure 3B). The extent of myocardial inclusion varies from heart to heart. The right coronary sinus and the anterior part of the left coronary sinus are involved. The remaining part of the left coronary sinus and the whole of the non-coronary sinus do not contain myocardium. In human, myocardium is present in the non-coronary and posterior half of the left-coronary sinus only when there is persistence of the left ventriculo-infundibular fold (inner heart curvature) but this seldom happens. Usually, the fold disappears completely resulting in fibrous continuity between aortic and mitral valves. The area of valvar continuity is thickened at both ends to form the right and left fibrous trigones; the right trigone contributing to the central fibrous body of the heart (see next section).
The anatomic ventriculo-arterial junction, however, does not coincide with the functional junction, again owing to the configuration of the semilunar hingelines. First, the ventricular parts within the aortic sinuses become incorporated, functionally, into the aorta. Second, the parts of the wall of the aortic sleeve that are in between adjacent leaflets, lie above the anatomic ventriculo-arterial junction but become, haemodynamically, a part of the ventricle when the valve is closed. These triangular-shaped portions deserve special consideration (see below) (Figure 3C).
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Interleaflet fibrous triangles |
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The semilunar attachments of the leaflets across the anatomic ventriculo-arterial junction and into the aortic sleeve leave three pieces of wall in between the arcs. These are the interleaflet fibrous triangles (also described as interannular trigones or fibrous trigones, intervalvaular trigone) that project above the ventricular mass like three prongs of a coronet (Figure 3D and E), in potential communication with extracardiac space. McAlpine2 has pointed to these areas as potential sites of aneurysmal formation. The triangles are thinner and less collagenous than the hingelines or the sinusal walls. The triangle between the left and right coronary sinuses lies immediately behind the right ventricular outlet. The triangle between the left-coronary and non-coronary leaflets is along the area of aortic-mitral fibrous continuity but its upper part abuts on the transverse pericardial sinus.18 The triangle between the right- and non-coronary leaflets adjoins the interventricular part of the membranous septum which, together with the right fibrous trigone, forms the central fibrous body (Figure 3C). The latter is the landmark for the site of the His bundle of the cardiac conduction system. Having penetrated the central fibrous body, the atrioventricular conduction bundle passes between the membranous septum and the crest of the muscular ventricular septum to bifurcate into right and left bundle branches. Thus, the interleaflet triangle between the right- and non-coronary leaflets is a good guide to the atrioventricular conduction bundle and the proximal portion of the left bundle branch. The latter, covered with a fibrous sheath, is often visible in the subendocardium of the outflow tract in heart specimens.
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The normal functional unit |
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Considering the aortic root as one functional unit, it is a three-dimensional structure adjoining distally to the aorta and proximally to the ventricle, and all parts have to work in harmony. When there is dysfunction it is unlikely to involve only a single element, apart from, for example, isolated perforation of the leaflet.
Using 25 perfusion fixed preparations of human aortic roots, Berdajs et al.7 found the mean circumference to be 65.8 mm at the sinutubular junction and 69.2 mm at the base of the root. Using only 10 specimens and without pressure fixation, Kunzelman et al.19 similarly found the sinutubular junction to be narrower than the basal part and the middle of the sinusal part was the widest. In the living, the shape of the aortic root changes through the cardiac cycle. Thubrikar et al.20 found that the diameter at the sinutubular junction and at the nadirs of the leaflets change continuously during the cardiac cycle in their experiments on dogs. During systole the sinutubular junction increases initially as aortic pressure increases and decreases later as aortic pressure drops, and the base decreases so the root adopts a cylindrical shape.21 During diastole the sinutubular junction moves inwards and the base moves outwards commissures, changing the cylindrical shape to a more conical shape.
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Abnormal/pathological variants |
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In terms of number of leaflets, the aortic valve can have 1–4 leaflets of variable sizes. Functional abnormality may be considered in terms of aortic stenosis and aortic regurgitation. In some cases, the valve is both stenotic and regurgitant when the orifice becomes more or less like a fixed aperture.
The most common variant is the aortic root that has two leaflets. The bicuspid aortic valve reportedly has an incidence of 1–2% or 0.9–2.5% in the normal population.22,23 The majority are not symptomatic and have no clinical signs. But, as a group, they tend to have a higher incidence of sclerosis or calcification on the leaflets leading to them presenting at a younger age with aortic stenosis compared to patients with a normal three-leaflet valve. The morphology of the bicuspid aortic valve is variable (Figure 4A and B).24 The valve leaflets may be nearly equal in size, or one leaflet may be large and the other much smaller. The larger leaflet very often has a raphe in the middle marking the place where the leaflet should have divided during development. Some bicuspid valves show a cleft in one leaflet suggesting incomplete separation into two leaflets during development, whereas others are the consequence of acquired fusion occurring late in life. These may be distinguished from true bicuspid valves by tracing the free edge of the pseudocommissure towards the sinutubular junction but it can be difficult in practice. In these valves, three interleaflet triangles and three sinuses may be detected. The triangle underneath the fusion line may be nearly as tall as the other triangles. In contrast, the triangle lying beneath the raphe of a bicuspid valve is reduced in height considerably, contributing to restricting leaflet mobility.25 A minority have two nearly equal leaflets, two sinuses, and two interleaflet triangles.24 The leaflets of the bicuspid valve are arranged in either antero-posterior or left–right orientations. Antero-posterior is more common, occurring in 79% of the cases and both coronary arteries take origin from the anterior sinus that has the raphe.8 In the left–right arrangement, a coronary orifice can be found in each sinus, with the raphe always in the right leaflet. The valvar orifice may also be restricted by the total length of the free edge of the leaflets. If the leaflets are redundant along the free edge, the orifice is less likely to be stenotic.22 Calcification of a bicuspid valve begins first along the raphe and also on the aortic surface of the other leaflet.8
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Minor degrees of calcification involving the three-leaflet aortic valve are common in the elderly. Degenerative valvar stenosis caused by calcification is more commonly seen in patients over the age of 65 years (Figure 4C). In such cases, commissural fusion is absent or minimal except where there has been concomitant rheumatic valve disease.26 The valvar orifice assumes a triangular shape. The leaflets are stiff with nodules on the aortic aspect along the hingelines. Davies8 likened this to ‘fusing the hinge of a door’, rendering the leaflets immobile.
In contrast, stenosis occurring in a tricuspid (trifoliate) aortic valve in infants and children often is due to dysplasia of the valvar leaflets (Figure 4D and E). The leaflets are thick, irregular, and gelatinous looking, with a mucoid tissue core in place of the normal layered arrangement.
The unicuspid (unifoliate) and unicommissural aortic valve occurring in isolation is rare. More often, it is associated with congenital malformations of the left heart. The solitary leaflet is attached circumferentially like a skirt around the eccentrically situated orifice (Figure 4F). Often the orifice is shaped like a key-hole. The valve represented by a dome-shaped membrane, without any commissure, is more commonly seen guarding the pulmonary trunk than the aorta. Usually, three shallow raphes may be found on the aortic aspect at the base of the dome. The orifice is usually centrally situated.
The quadricuspid aortic valve is extremely rare and may become stenotic as calcification develops. However, according to McAlpine,2 the quadricuspid valve with leaflets of equal size usually is regurgitant. He opined that the ratio between leaflet surface area and hingeline is increased, deviating from the optimal ratio that is in the tricuspid design.
So-called supravalvar stenosis is less frequent than valvar stenosis. Conventionally, three morphology forms are recognized: an hourglass deformity, a fibrous membrane with central orifice, and a diffusely hypoplastic ascending aorta (Figure 5A and B).27 As discussed earlier, the aortic root should be considered as one functional unit. So-called supravalvar stenosis often involves the sinutubular junction as well as the aortic leaflets and sinuses and may be included as valvar stenosis. In the hourglass form, the sinutubular junction is narrow, the free margins of the leaflets are shorter than normal relative to the height of the leaflets so they resemble pockets with narrow openings, and the leaflets tend to be redundant (Figure 5A).28
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Subaortic stenosis takes various forms but the form that approximates to the aortic root is the discrete form.29 This lesion is like a fibrous shelf or ridge that can lie immediately underneath the base of the valvar leaflets and extend to the area of aortic-mitral valvar continuity.
Aortic regurgitation is less common than aortic stenosis. The substrates for regurgitation are classified into three categories that may occur in combination: leaflet abnormality, root enlargement or distortion, and loss of commissural support.8 Leaflet abnormality may be due to perforation or tear, or prolapse in a leaflet of regular size be it a valve with two or three leaflets. Reduction in leaflet size, e.g. by fibrosis in rheumatic and post-inflammatory valve disease, can also result in regurgitation. This is because the total area of the leaflets in the normal valve exceeds the area of the aortic root. This relationship is disturbed either when the leaflets become smaller or the root area becomes enlarged (Figure 6), or a combination of both. In a necropsy study, Silver and Roberts9 found that the area of the aortic orifice at the sinutubular junction increased with age from 300 mm2 at 40 years to 450 mm2 at 70 years (or diameters of 19.54 and 23.92 mm, respectively) in normal hearts. The normal circumference is not more than 9 cm (diameter of 28.64 mm), which corresponds closely to the upper limit of aortic root diameter of 3.4 cm on echocardiography.8 The cross-sectional area also increased with heart weight.9 Without concomitant expansion of the leaflets, the apposing edges between adjacent leaflets which normally are approximately one-third of the maximal leaflet height become less and less until a perfect seal is no longer possible. When this happens and only one leaflet prolapses, the defect is eccentric. The free edge of the prolapsed leaflet becomes fibrotic and considerably thickened. On transthoracic echocardiography, the bicuspid aortic valve is shown to be more vulnerable to disproportionate increase in root diameter that the valve with three leaflets.30
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Aortic regurgitation due to loss of commissural support may be exemplified by dissection in the aortic wall immediately above the commissures allowing one or more cusps to prolapse into the ventricle but this is rare. More often, dissection begins 2–3 cm above the sinutular junction and then tracks downwards, particularly affecting the right coronary leaflet.8 Another scenario for lack of support is the presence of a ventricular septal defect immediately underneath the aortic valve. Venturi effect on the aortic leaflet, usually the right leaflet, causes it to prolapse towards the defect.
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Conclusions |
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The aortic root is one unit comprising of several elements. The elements have been presented, one-by-one, simplistically in this review but normal function is dependent on all the elements working together but it does not work in isolation. Abnormal function of the aortic valve often affects more than one element of the unit. Furthermore, the unit does not function in isolation. The structures adjoining the unit must also be included but, owing to space limitations, the adjoining ascending aorta and the ventricular structures are not discussed in detail. In clinical practice, systemic examination of the aortic root at defined levels using cross-sectional echocardiography may allow better planning of treatment strategies for patients.11
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Funding |
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The Cardiac Morphology Unit at the Royal Brompton Hospital receives funding support from The Royal Brompton and Harefield Hospital Charitable Fund.
Conflict of interest: none declared.
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References |
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- Walmsley T. The heart. In: Quain's Elements of Anatomy.—Sharpey-Schaffer T, Symington J, Bryce TH, eds. (1929) London: Longmans, Green & Co. 42–53.
- McAlpine WA. Heart and Coronary Arteries (1975) Berlin: Springer-Verlag. 9–26.
- Liberman L, Pass RH, Kaufman S, Hordof AJ, Printz BF, Prakash A. Left coronary artery arising from the non-coronary sinus: a rare congenital coronary anomaly. Pediatr Cardiol (2005) 26:672–4.[CrossRef][Web of Science][Medline]
- Garg A, Ogilvie BC, McLeod AA. Images in cardiology. Anomalous origin of the left coronary artery from the non-coronary sinus of Valsalva. Heart (2000) 84:136.
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- Berdajs D, Lajos P, Turina M. The anatomy of the aortic root. Cardiovasc Surg (2002) 10:320–7.[CrossRef][Web of Science][Medline]
- Davies MJ. Pathology of Cardiac Valves (1980) London: Butterworths & Co. 1–61.
- Sliver MA, Roberts WC. Detailed anatomy of the normally functioning aortic valve in hearts of normal and increased weight. Am J Cardiol (1985) 55:454–61.[CrossRef][Web of Science][Medline]
- Choo SJ, McRae G, Olomon JP, St George G, Davis W, Burleson-Bowles CL, et al. Aortic root geometry: pattern of differences between leaflets and sinuses of Valsalva. J Heart Valve Dis (1999) 8:407–15.[Web of Science][Medline]
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