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Department of Cardiac Surgery, European Hospital, Rome, ItalyDepartment of General and Specialized Surgery “Paride Stefanini,” Sapienza University, Rome, Italy
Department of Cardiac Surgery, European Hospital, Rome, ItalyDepartment of Cardiac Surgery and Heart Transplantation, San Camillo Forlanini Hospital, Rome, Italy
During the last decade, special concerns have been raised about the anatomic relationships among the sinotubular junction, ventricular-aortic junction, and virtual basal ring to improve the results of root reconstruction. The aim of this study is to evaluate the in vivo anatomy of the aortic root after reimplantation with the Valsalva graft and the anatomic relationship between its components.
Methods
We analyzed 10 consecutive patients with tricuspid aortic valves who underwent reimplantation with the Valsalva graft between September and December 2019. Surgical clips were applied as markers at the level of proximal annular knots and at the distal reimplanted commissures on the neo-sinotubular junction. Electrocardiogram-gated computed tomography scan of the aortic root was performed. Coordinates of the markers were exported on a 3-dimensional modeling software, and the distances between the virtual basal ring and the Dacron graft basal landmarks were measured.
Results
The mean heights of Dacron graft basal landmarks from virtual basal ring were right-left commissure 7.1 ± 5.1 mm; right sinus 4.7 ± 4.1 mm; right-noncoronary commissure 2.8 ± 2.2 mm; noncoronary sinus 1.4 ± 1.6 mm; left-noncoronary commissure 2.2 ± 2.3 mm; and left sinus 2.0 ± 0.9 mm. The mean planar distances of basal Dacron graft landmarks from virtual basal ring (thickness) were right-left commissure 5.3 ± 3.1 mm; right sinus 2.8 ± 1.4 mm; right-noncoronary commissure 2.2 ± 1.5 mm; noncoronary sinus 1.5 ± 1.5 mm; left-noncoronary commissure 1.3 ± 1.0 mm; and left sinus 3.4 ± 2.5 mm.
Conclusions
After reimplantation, despite a complete dissection of the root, slight asymmetry of graft proximal seating exists. The inner annuloplasty is on the virtual basal ring, and the proximal edge of the Dacron graft is on the ventricular-aortic junction at a slightly different thickness and height along the annular circumference. At the level of the right sinus and left/right commissure, the Dacron graft is higher than the virtual basal ring and the relative wall thickness is increased. The annular stabilization is unaffected.
The anatomic skeleton of the aortic root after reimplantation is characterized by a slightly tilted position of the Dacron graft that is higher and farther from the VBR at the level of right sinus and right-left commissure.
This is the first in vivo human study to analyze the anatomic skeleton of the aortic root after reimplantation. Despite a complete dissection of the root and an effective annular stabilization, slight asymmetry of graft proximal seating exists. The inner annuloplasty is on the VBR, and the proximal edge of the Dacron graft is on the ventricular aortic junction at a different thickness and height along the annulus circumference.
See Commentaries on pages 1343 and 1344.
The aortic root is a complex region of the heart, where it joins the left ventricle to the arterial system performing a double function. First, the aortic root represents the structural continuity between the left ventricular muscle and the ascending aorta. The ventricular-aortic junction (VAJ) is the locus where the ventricular muscular fibers join the connective collagen fibers of the aortic root, representing a real anatomic connection. Second, the VAJ has a major role in generating the physiologic bloodstream dynamics. The VAJ houses the aortic valve and is the unit where the blood flow arises into the arterial system and takes its unidirectional antegrade characteristics. In this setting, the peculiar morphology of the Valsalva sinuses promotes the bloodstream fluid-dynamics during the cardiac cycle, allowing smooth movement of the aortic leaflets and a laminar coronary flow. Although the VAJ appears to be a static unit, its morphology is functional to the fluid-structure interaction of the blood flow. Thus, it has a central role in the cardiac function with every single component playing a specific action, like every single gear in a complex mechanism.
Each single component of the aortic root has been studied for decades by surgeons, cardiologists, and anatomists. In some cases, definitions and nomenclature have been controversial. The “myth” of the aortic annulus recognizes several definitions. The echocardiographic aortic annulus is defined by a mono-dimensional line representing the diameter of the virtual basal ring (VBR). The surgical aortic annulus is often described as the crown-like line attachment of the aortic leaflets to the root, where the valve prostheses are usually sutured. The hemodynamic aortic annulus is the area encompassed by the aortic leaflets in a closing position during the diastolic phase of the cardiac cycle. Finally, the anatomic aortic annulus is represented by a tridimensional structure connecting the aortic root from its upper to its lower portion. In this setting, the aortic annulus embodies the skeleton of the aortic root. It is represented by the histologic continuity among the collagen fibers at the level of the VAJ, the interleaflet triangles, the basal attachment of the aortic leaflets, the aortic commissures, and the sinotubular junction (STJ). These structures closely connected represent a single anatomic unit with clear geometric relationships.
described the functional aortic annulus where the STJ, the basal ring of the aortic valve, and the crown-like attachment of the aortic leaflets were grouped in a single anatomic-functional unit, useful to classify the complex mechanisms of aortic valve regurgitation.
Beyond these premises, aortic valve–sparing root replacement and repair represent a better alternative to replacement with prosthetic valves in terms of quality of life and risk of endocarditis. However, a deep knowledge of the anatomy of the aortic valve and the root is needed to master this surgical field.
Anatomic studies on the aortic valve and root to improve the knowledge of repair-oriented anatomy usually have been performed on human cadavers. The normal anatomic relationships among the STJ, VAJ, and VBR have been explored in the setting of aortic valve–sparing or aortic valve repair with annuloplasty.
The aim of this study is to describe the in vivo anatomy of the aortic root after a reimplantation technique with the Valsalva graft in terms of reconstruction of its anatomic components, VBR, VAJ, sinuses of Valsalva, STJ, and proper restoration of their anatomic relationships.
Materials and Methods
Patients
This is a prospective, observational study. From September 2019 to December 2019, all 10 consecutive patients who underwent aortic valve reimplantation with a Valsalva graft were enrolled in the study. Inclusion criteria were the presence of isolated aortic root aneurysm with secondary aortic regurgitation of any grade, type Ic of El Khoury classification, on a tricuspid aortic valve.
Redo surgery, calcifications of the aortic root or the ascending aorta, bicuspid aortic valve, and the presence of any cusp abnormalities as retraction, calcifications, and fenestrations or perforation were considered as exclusion criteria. Baseline characteristics are summarized in Table E1. The study was approved by the internal ethical committee, and all patients consented to participate.
Surgical Technique
The surgical technique of aortic valve reimplantation has been described in previous work
; it has been standardized and was not significantly modified during the study period. In brief, dissection is conducted as deep as possible along the whole root circumference. Then, the proper conduit size is chosen and a series of 6 pledgeted sutures are placed circumferentially along the VBR, one at the nadir of each aortic cusp and one at the base of each interleaflet triangle. These sutures are then passed at the established level of the Valsalva graft and used to anchor it to the annulus. The commissures are pulled inside the graft and fixed at the new STJ. The valve remnants are then sutured, and coronary ostia reattached. Suture of the graft to the distal aorta completes the procedure.
Markers Rationale and Computed Tomography Reconstructions
The pledgeted sutures placed at the VBR (Figure 1, A) and used to fix the Dacron graft to the annulus were tied over an Hegar dilator of proper size to perform the annuloplasty. After the sutures were tied, surgical clips were applied as markers at the base of the 6 annular knots, to be as close as possible to the Dacron wall (Figure 1, B). After suturing the valve remnants to the Dacron wall, 3 more surgical clips were positioned on the knots fixing the top of each commissure to the Dacron graft at the level of the neo-STJ (Figure 1, C). Surgical clips were used to highlight the spatial coordinates of the Dacron graft and its related anatomic structure at the computed tomography (CT) scan study, which was performed between postoperative days 4 and 10.
Figure 1Intraoperative view of surgical markers. They were arranged in 3 different lines easily detectable with ECG-gated CT scan. The first line (A) positioned at the level of the inner circumference of the VBR is represented by the 6 pledgets of the annuloplasty sutures. The second line (B) placed on the external circumference of the annulus is represented by the surgical clips positioned on the knots of the annuloplasty sutures (Dacron graft basal landmarks). The third line (C) positioned at the level of the STJ is represented by the surgical clips placed on the knots used to fix the top of each commissure (STJ commissural landmarks).
In this way, we obtained a series of markers arranged in 3 different lines easily detectable with CT scan. The first line is positioned at the level of the VBR on the inner circumference of the root and is represented by the pledgets of the annuloplasty sutures (Figure 2, A). The second line is on the outer circumference of the root and is represented by the surgical clips positioned on the knots of the annuloplasty sutures, referred to as “Dacron graft basal landmarks” (Figure 2, B). The third line is represented by the surgical clips positioned on the knots of the sutures fixing the commissures at the level of the neo-STJ on the external circumference of the Dacron wall, referred to as “STJ commissural landmarks” (Figure 2, C).
Figure 2ECG-gated CT scan reconstructions after aortic valve reimplantation with Valsalva graft. A, Short-axis view showing the 6 pledgets at the level of VBR on the inner circumference of the root. B, Short-axis view showing the surgical clips at the level of the 6 annular sutures on the outer circumference of the aortic annulus. C, Short-axis view showing the surgical clips on the knots used to fix each commissure at the level of the Dacron neo-STJ.
ECG-gated, contrast-enhanced CT scan of the aortic root was performed with an adequate heart rate to minimize possible artefacts. The CT protocol included ECG-retrospective, contrast-enhanced CT scan of the entire thoracic aorta after injection of a bolus of 70 to 90 mL of iomeprol 400 mg I/dL (Iomeron 400; Bracco, Milan, Italy) at a flow rate of 5 mL/s, followed by a 30-mL saline flush, using a 64-slice CT scanner (Brilliance 64; Philips, Cambridge, Mass). CT data sets were reconstructed with a slice thickness of 1 mm (reconstruction increment 0.5 mm) at 70% of the R-R interval using a medium-smooth convolution algorithm and an image matrix of 512 × 512 pixels. Dedicated multiplanar planes were reconstructed applying the double oblique view to obtain an axial plane perpendicular to the long axis of aortic root. The axial image passing through the left ventricular outflow tract immediately below the nadir of the 3 leaflets was identified as the VBR, and it was always determined using the method of multiplanar reconstruction. Aortic annulus geometric parameters were then measured: major diameter, minor diameter, perimeter, area, and ellipticity index as minor diameter/major diameter ratio; neo-root diameters were measured (off-center right, off-center left, and bisecting).
The differences between bisecting and off-center cuts of the aortic root: the three-dimensional anatomy of the aortic root reconstructed from the living heart.
Marker coordinates were exported on a 3-dimensional (3D) modeling software (SketchUp; Trimble Inc, Sunnyvale, Calif), and their relationships were analyzed on the 3D model. In particular, the distances between the VBR and the Dacron graft basal landmarks were measured, on either the flow axis plane (height) or the VBR plane (thickness). Likewise, the distances of STJ markers from VBR (internal commissural height) and Dacron graft basal landmarks (external commissural height) were measured. The tilt angle between the VBR plane and the STJ plane was also calculated (Figure 3, Video 1, and Table E1).
Baseline patients characteristics and VBR geometrical characteristics and neo-root diameters are summarized in Tables 1 and 2. Dacron graft basal landmarks mean heights from VBR plane (as distance on flow axis–orthogonal plane) were greater at level of right-left (R-L) commissure and right sinus (6.1 ± 3.4 mm and 4.9 ± 3.9 mm, respectively) and smaller at level of noncoronary (NC) sinus and left sinus (1.4 ± 1.6 mm and 2.0 ± 0.9 mm, respectively). Dacron graft basal landmarks mean distances from VBR, on VBR plane (defined as thickness) were larger at R-L commissure (4.8 ± 2.7 mm) and right sinus (2.8 ± 1.4 mm) and smaller at NC sinus (1.5 ± 1.5 mm) and left noncoronary (L-NC) commissure (1.3 ± 1.0 mm). Distances from STJ landmarks to VBR and basal Dacron landmark were defined as inner commissural height and outer commissural height. They were 26.3 ± 4.7 mm, 27.4 ± 5.6 mm, 24.0 ± 5.0 mm for R-L, R-NC, and L-NC commissural inner heights, respectively, and 20.5 ± 4.9 mm, 23.6 ± 6.7 mm, and 20.6 ± 5.4 mm (R-L, R-NC, and L-NC commissural outer heights), respectively. Mean tilt angle between VBR and STJ planes was 16.2° ± 8.1°. These findings are summarized in Table 3 and Figures 4 and 5.
Table 1Baseline characteristics of enrolled patients
Figure 4The aortic root shows the different heights (blue area) of the Dacron graft in respect to the VBR (green line). At the level of right sinus and left/right commissure, the Dacron graft is higher; conversely, the external dissection of the root allows one to reach the outer level of the VBR more easily in the rest of the root circumference (left). Schematic representation of distances between the annuloplasty sutures (identified by the pledgets) and the Dacron graft basal landmarks (proximal edge of Dacron graft) on VBR plane, defined as thickness (orange area). At the level of right sinus and right-left commissure, the graft is farther away from the VBR (right). L, Left; R, right; NC, noncoronary.
Figure 5Chart representing the Dacron graft basal landmarks mean heights from VBR plane (as distance on flow axis–orthogonal plane) (left), and the Dacron graft basal landmarks mean distances from VBR on VBR plane (defined as thickness) (right). L, Left; R, right; NC, noncoronary.
The aortic root has a well-defined and complex 3D structure, where each component plays a role to guarantee valve competency and hemodynamic efficiency. When a valve-sparing root reconstruction is performed, the symmetry between its components is certainly perturbed; we aimed to develop a better understanding of the neo-root anatomy after aortic valve reimplantation with the Valsalva graft and the precise relationship of its key components.
The rationale of this work was inspired by previous studies by Berdajs and colleagues,
where aortic root anatomy and function were analyzed in the context of aortic valve repair surgery. In animal models, they used micro sonometric crystals at determined point of interest (valve commissures, VBR, and STJ) to assess the spatial relationships of aortic root components and functional features.
Although our analysis is limited to a single phase of the cardiac cycle (mid diastole) and does not consider any dynamic or functional aspect, we tried to go one step further: overcoming the animal model and analyzing the effective postreimplantation human anatomy.
A review of the literature reveals that no other studies report the assessment of the topographic relationship among all components of the aortic root as the VAJ, VBR, STJ, sinuses of Valsalva, and aortic leaflets after valve-sparing surgery in humans. In this study, the in vivo topographic anatomy of the aortic root after reimplantation using a graft with sinuses has been investigated using ECG-gated CT. We observed an accurate reconstruction of the main structures of the natural aortic root. Proceeding from the bottom up, all the structures appeared to be arranged as in the normal human anatomy. The VBR and VAJ were distinct structures, and their respective anatomic relationships were preserved. At the level of the VBR, on the inner side of the root, identified with CT scan images as described by Mori and colleagues,
The differences between bisecting and off-center cuts of the aortic root: the three-dimensional anatomy of the aortic root reconstructed from the living heart.
all pledgets implanted during the procedures, were simultaneously identifiable in a circular line close to the nadir of aortic leaflet and at the base of the interleaflet triangles. All pledgets were found in the proper position at the native VBR, where they resized and reshaped the annulus. In fact, the VBR that is usually elliptical after surgery is modified in a more circular shape.
Morphological modification of the aortic annulus in tricuspid and bicuspid valves after aortic valve reimplantation: an electrocardiography-gated computed tomography study.
The clips used as marker for the proximal, basal end of the Dacron graft were disposed to a slightly upper (cranial) level in respect to the VBR (the distance between the pledgets and the basal clips). The clips corresponding to the noncoronary sinus were the closest to the VBR, and the clips corresponding to the left/right commissure were the farthest. Overall, the line described by the clips represents a circular line with 3-dimensional characteristics, farther from the VBR where the muscular and membranous septum are present, while closer to the VBR at the level of the mitro-aortic curtain and noncoronary sinus. Furthermore, clip disposition also reflects the variation in thickness, with similar behavior. At the level of R-L commissure and right sinus the distance is greater (and the VAJ is thicker), whereas it is smaller at the NC sinus (where the VAJ is slimmer). In the normal human anatomy, the VAJ is where ventricular myocardium ends and gives way to the wall of the aortic tissues. It is a real anatomic entity describing an almost circular line with a slight 3-dimensional silhouette. The natural VAJ is farther at the level of the right coronary sinus and closer at the level of the noncoronary sinus respect to the VBR. As shown in Figure 3, the solid shape designed by the pledgets and the clips allows identification of both structures, the VBR and the VAJ, reproducing the normal human anatomy with a faithful preservation of their normal relationships.
The importance of VAJ has been widely observed in the setting of valve-sparing surgery and the pathophysiology of the aortic valve. Dilatation of the annulus is almost always present in the presence of aortic regurgitation. Aortic annuloplasty is a protective factor in valve-sparing root replacement and aortic valve repair, and an untreated dilated aortic annulus is a major risk factor for failure of aortic valve repair, both in bicuspid and tricuspid aortic valves.
Anatomic studies investigating the internal root height or volume of the sinus of Valsalva in pressurized and chemically fixed aortic roots evidenced that left coronary sinus was the smallest sinus, whereas the right coronary sinus and the noncoronary sinus were found to be relatively larger. Because of this difference, a tilt angle of 5.5° to 11° between the VBR and STJ planes was also observed.
observed a similar internal root height among the 3 sinuses, although the external root height was significantly greater at the noncoronary sinus and left coronary sinus compared with the right coronary sinus (due to the nonplanar nature of the VAJ). However, the study by de Kerchove and colleagues
was in the setting of nonpressurized cadaver root specimens. In our study, we can confirm the presence of a tilt angle between VBR and STJ and a slightly taller R-NC commissure. This could also be explained by the dynamic behavior of the root (or neo-root) in vivo, where the natural curvature of the ascending aorta tends to compress the L-NC and left-right commissures and extend the R-NC commissure.
Although differences between the 3 inner commissural heights are explained by the tilt angle, we also found a consistent difference between the inner and outer height of each commissure. This finding is consistent with the difference in height and thickness of the VAJ in respect to the VBR (higher and farther position of the basal Dacron clips in respect to the pledgets).
Study Limitations
Despite the high spatial resolution of CT images, there is a measurement bias that should be considered. The 2-dimensional silhouette of the surgical hemoclips has a length of 2 to 3 mm, and the sutures knots where the clip is attached could vary. Consequently, the present measures cannot be interpreted as absolute “true” anatomic distances. Considering that all markers are subjected to the same bias, their global spatial arrangement is maintained and might represent a real anatomic reconstruction.
Conclusions
In the reimplantation procedure, despite a complete dissection of the root, slight asymmetry of graft proximal seating exists. The inner annuloplasty, made by Teflon pledgets, is on the VBR, whereas the outer annuloplasty, the proximal edge of Dacron graft, is on the VAJ at a slightly different thickness and height along the annulus circumference (Figure 6). This does not impair an effective annular stabilization and mimics the native structure of the human aortic annulus.
Figure 6The marker positions on the Dacron graft after a reimplantation procedure (drawing), their visualization on the CT scan, and their 3D reconstruction (schematic). This sequence shows that the anatomic skeleton of the root after reimplantation is characterized by a slightly tilted position of the Dacron graft higher and farther from the VBR at the level of the right sinus and R-L commissure similar to the relationship between the natural VAJ and the VBR. ECG, Electrocardiogram; CT, computed tomography; 3D, 3-dimensional; STJ, sinotubular junction; L, left; R, right; NC, noncoronary; VBR, virtual basal ring.
As the inventor of the Valsalva graft described in the article, R.D.P. has received royalties from Terumo Aortic in the past. All other authors reported no conflicts of interest.
The Journal policy requires editors and reviewers to disclose conflicts of interest and to decline handling or reviewing manuscripts for which they may have a conflict of interest. The editors and reviewers of this article have no conflicts of interest.
The degree of aortic root dissection, the intraoperative placement of the hemoclips as radiopaque markers followed by a CT analysis, and marker position extrapolation necessary for a 3D reconstruction of the aortic root skeleton. Video available at: https://www.jtcvs.org/article/S0022-5223(21)00695-4/fulltext.
The degree of aortic root dissection, the intraoperative placement of the hemoclips as radiopaque markers followed by a CT analysis, and marker position extrapolation necessary for a 3D reconstruction of the aortic root skeleton. Video available at: https://www.jtcvs.org/article/S0022-5223(21)00695-4/fulltext.
Appendix E1
Table E1Individual patient characteristics and individual data of the reconstructed anatomy of the whole aortic root
Patient
Baseline characteristics
Male sex
Age (y)
BSA (m2)
Graft size (mm)
1
1
62
1.94
32
2
1
62
2.21
32
3
1
58
2.03
32
4
1
46
2.48
32
5
1
72
2.07
32
6
1
61
2.00
32
7
1
70
1.88
32
8
1
59
2.08
32
9
1
53
2.04
32
10
1
62
1.94
32
ECG-gated CT scan geometrical findings of reconstructed aortic annulus and aortic root
VBR features (mm)
Valsalva sinuses diameters (mm)
MD
md
P
A (mm2)
EI
OC-R
OC-L
Bisecting
Patient
25.7
24.4
77.5
457
1.05
38.3
38.2
37
1
26.6
23.4
85.2
516
1.14
37.6
37.3
34.6
2
24.8
21
76.3
432
1.18
38
37.5
37.4
3
25.2
20.1
69.7
402
1.25
37.8
38.3
34.5
4
25.3
22.5
79.2
475
1.12
39.8
39.5
37.3
5
26.9
25.4
87.3
550
1.06
37.7
33.9
33.3
6
28.7
25.6
91.5
591
1.12
39.8
39.6
36.9
7
27
23.7
83
584
1.14
38.7
38.3
34.6
8
23.8
21.4
79.8
452
1.11
36.6
36.8
34.5
9
25.5
22.8
75.9
449
1.12
39
38
35.3
10
25.7
24.4
77.5
457
1.05
38.3
38.2
37
Patient
Mean Dacron graft landmark height from VBR plane, (mm)
R-L commissure
R sinus
R-NC commissure
NC sinus
L-NC commissure
L sinus
1
5.02
4.19
1.04
0.13
0.48
2.69
2
6.83
8.33
4.67
1.07
2.38
2.59
3
7.90
3.69
1.32
1.18
1.39
1.91
4
4.64
4.06
6.60
5.50
4.51
2.10
5
4.52
5.66
2.01
0.08
0.25
1.20
6
1.30
1.48
0.80
1.74
3.77
3.23
7
11.2
10.05
4.86
1.93
0.72
1.60
8
8.56
10.99
4.37
0.28
0.63
2.51
9
9.96
0.10
1.84
1.34
7.06
1.87
10
0.96
0.35
0.19
0.44
0.39
0.06
Patient
Mean landmark distance from VBR, on VBR plane (thickness), (mm)
R-L commissure
R sinus
R-NC commissure
NC sinus
L-NC commissure
L sinus
1
4.29
3.09
2.05
0.48
0.36
1.53
2
2.85
2.52
4.22
3.75
3.70
3.43
3
4.19
0.91
4.30
4.24
1.83
1.61
4
6.39
3.25
3.77
1.48
0.91
2.55
5
2.95
3.40
1.49
0.29
1.38
4.23
6
1.09
1.63
1.15
1.51
2.07
0.66
7
4.31
4.48
1.19
0.54
0.69
5.78
8
8.12
4.02
0.51
0.42
0.49
9.06
9
10.12
4.39
2.86
2.57
1.43
1.95
10
3.47
0.35
0.07
0.24
0.31
3.70
Patient
Mean outer commissural height, (mm)
Mean inner commissural height, (mm)
R-L commissure
R-NC commissure
L-NC commissure
R-L commissure
R-NC commissure
L-NC commissure
1
23.6
32.1
21
29.1
31.1
22.2
2
18
18
17.4
26.2
24.8
22.3
3
20.9
23.1
20.2
28.4
25.4
23.4
4
13.3
19.4
17.5
20
20
24.8
5
29.3
24.8
29
33.2
32.9
29.6
6
14.3
15
15.4
17.6
17.3
21.3
7
19.3
30.9
16.5
26.5
32.6
19
8
18.2
14.6
14.7
26.1
26
15.7
9
23.2
31
25.7
30.8
33.5
31
10
25
27.3
29
25.4
30.1
30.3
Patient
Mean VBR—STJ tilt angle, (°)
1
26.80
2
9.60
3
9.60
4
20.20
5
4.90
6
9.30
7
25.40
8
26.90
9
14.30
10
14.80
BSA, Body surface area; ECG, electrocardiogram; CT, computed tomography; VBR, virtual basal ring; MD, major diameter; md, minor diameter; P, perimeter; A, area; EI, ellipticity index; OC-R, off-center right; OC-L, off-center left; R, right; L, left; NC, noncoronary; STJ, sinotubular junction.
The differences between bisecting and off-center cuts of the aortic root: the three-dimensional anatomy of the aortic root reconstructed from the living heart.
Morphological modification of the aortic annulus in tricuspid and bicuspid valves after aortic valve reimplantation: an electrocardiography-gated computed tomography study.
The skeleton of the aortic root is a complex structure consisting of the virtual basal ring, aortoventricular junction, and sinotubular junction.1 In brief, the virtual basal ring is defined by the nadirs of the aortic valve leaflets. The aortoventricular junction is where the ventricular septum and aortic–mitral curtain intersect with the arterial system. The sinotubular junction is demarcated by the top of the aortic valve commissures. The interplay between the aortic leaflets and anatomic skeleton dictates the function of the aortic root.
The anatomic demarcation between the left ventricular outflow tract (LVOT) and the aortic root, and thus the beginning of the arterial system, is the ventriculoaortic junction (VAJ). However, in an anatomic study in human hearts, we have demonstrated that the VAJ is rather curvilinear.1 It crosses the base and insertion of the right coronary cusp and lays a few millimeters above the virtual basal ring (VBR; defined as the plane passing through the nadirs of each aortic cusp), in between the left/right and the right/noncoronary commissures.
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