improvement in the assessment of aortic valve and aortic...

J A C C : C A R D I O V A S C U L A R I M A G I N G VO L . - , N O . - , 2 0 1 9

ª 2 0 1 9 B Y T H E AM E R I C A N C O L L E G E O F C A R D I O L O G Y F O UN DA T I O N

P U B L I S H E D B Y E L S E V I E R

STATE-OF-THE-ART PAPER

Improvement in the Assessment ofAortic Valve and Aortic Aneurysm Repairby 3-Dimensional Echocardiography
Andreas Hagendorff, MD,a Arturo Evangelista, MD, PHD,b Wolfgang Fehske, MD,c Hans-Joachim Schäfers, MDd
ABSTRACT

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Reconstructive surgery of the aortic valve is being increasingly used in patients with aortic regurgitation and/or aortic

aneurysm. Its success depends on restoring normal aortic valve and root form. Echocardiography is the most reliable and

precise imaging technique because it defines abnormal morphology and function, essential for selecting appropriate

substrates and guiding the surgical strategy. Despite technical advances in echocardiography, aortic valve and aortic root

morphology and function are still assessed mainly using 2-dimensional echocardiography in clinical practice. This

review focuses on the need to use 3-dimensional echocardiography to characterize different forms of aortic valve and

root abnormalities and attempts to define echocardiographic predictors of successful valve-root complex repair.

(J Am Coll Cardiol Img 2019;-:-–-) © 2019 by the American College of Cardiology Foundation.

I n recent decades, assessment of the aortic valve(AV) has focused primarily on the type and de-gree of valve dysfunction (1). In addition, aortic

dimensions have been measured to determine theneed for prophylactic aortic surgery (2–4). Since2000, the increasing use of aortic repair proceduresfor the treatment of both aneurysm and aortic regur-gitation (AR) has led to a closer look at the exactanatomic and functional interaction of the differentaortic root components (5–10). It has becomeapparent that the combination of valve and root con-stitutes a functional unit (11–14). It is important to un-derstand that functionally, the cusps, annulus, andsinotubular junction (STJ) are integral parts of thevalve mechanism. Therefore, all these elementsneed to be considered when determining the mecha-nism of AR and for tailored surgical correction.Because both root and cusp abnormalities contributeto regurgitation, it has become clear that restoration

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m the aDepartment of Cardiology, University of Leipzig, Leipzig, German

ebron, CIBER-CV, Barcelona, Spain; cInnere Medizin III-Kardiologie,

epartment of Thoracic and Cardiovascular Surgery, Saarland Universi

thors have reported that they have no relationships relevant to the conte

nuscript received February 20, 2018; revised manuscript received May 31

of AV function requires normalization of valve androot anatomy. Successful AV repair thus requiresclose knowledge of the pathological components fora specific treatment plan to be established (15–18).

Echocardiography, both transthoracic echocardi-ography (TTE) and transesophageal echocardiography(TEE), plays a key role in the assessment of anatomyand function of the AV and aortic root. Recently,technological advances have taken place in 3-dimensional (3D) echocardiography regarding spatialand temporal resolution and surface rendering, andthis technique may significantly improve AV and theaortic root assessment (19–27). Dynamic 3D imaging ismandatory for evaluating and quantifying the spatialand functional relationship among components of theAV complex (28).

Using multiplane reconstruction, it is possible toadjust the orthogonal imaging planes for optimalvisualization of all 3 aortic coaptation lines and assess

https://doi.org/10.1016/j.jcmg.2018.06.032

y; bServei de Cardiologia, Hospital Universitari Vall

St. Vinzenz Hospital, Cologne, Germany; and the

ty Medical Center, Homburg/Saar, Germany. The

nts of this paper to disclose.

, 2018, accepted June 14, 2018.

https://doi.org/10.1016/j.jcmg.2018.06.032

ABBR EV I A T I ON S

AND ACRONYMS

2D = 2-dimensional

3D = 3-dimensional

AR = aortic regurgitation

AV = aortic valve

eH = effective height

gH = geometric height

I-I = inner edge–to–inner edge

LVOT = left ventricular outflow

tract

STJ = sinotubular junction

SoV = sinus of Valsalva

TAA = tubular ascending aorta

TEE = transesophageal

echocardiography

TTE = transthoracic

echocardiography

Hagendorff et al. J A C C : C A R D I O V A S C U L A R I M A G I N G , V O L . - , N O . - , 2 0 1 9

3D Echocardiography in Aortic Valve Repair - 2 0 1 9 :- –-

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the complex anatomy of 3D cusp anatomyand their geometric interrelationship withthe aortic root as a functional unit. Never-theless, the routine clinical use of 3D TEE islimited because 3D transesophageal echo-cardiographic equipment is not availableworldwide, and knowledge regarding theimaging options provided by 3D TEE ismissing or incomplete. In this review wepropose a systematic approach to the pre-and post-operative assessment of AVmorphology and function, especially using3D TEE and TTE, to provide more compre-hensive analysis and establish critical infor-mation on echocardiographic applications inpatients with AR and/or aortic aneurysm withrespect to the indication of an appropriate AVrepair technique. Understanding of the mor-phofunctional basis of aortic root anatomy

and diseases, as well as the possibility of dis-tinguishing the contribution of each single aortic rootcomponent in either AV dysfunction or aortic rootdilation, is a major clinical requirement for theanatomic-functional diagnosis and monitoring ofaortic root diseases.

ANATOMY OF THE AV AND

AORTIC ROOT COMPLEX

The aortic root encompasses the aortic cusps and islimited cranially by the STJ and caudally by the basalring (3,4,14,15,22), as illustrated in Figure 1 and theCentral Illustration (Videos 1 and 2). This basal ring oraortic annulus is not an anatomic ring but the com-bination of the crown-shaped cusp insertion lines(14,19,28). For these reasons, the term “aorticannulus” was deemed inappropriate by anatomists.From a geometric and functional perspective, the bestdefinition of the caudal border is probably the (vir-tual) basal ring (i.e., a plane connecting the nadirs ofthe cusp insertion lines). This plane, termed “aorticannulus” or “basal ring” in the present work, is cir-cular or elliptic and varies in shape between systoleand diastole.

The cusps are attached to the aortic root in acurved fashion, and there is a commissure between 2cusps. A normal commissure almost reaches the levelof the STJ. The ventricular-aortic junction is thetransition of ventricular structures to the aortic wall.This junction may be at the level of the nadirs of thecusp insertion lines.

The normal AV has 3 cusps of similar dimensionswith 3 commissures of normal equal height and analmost equal amount of cusp tissue. The coronary

ostia are below the level of the commissures. Thenumber of commissures of normal height determinesthe number of cusps (3,4). Cusp configuration ischaracterized by a height difference between theannular plane and the free margin of each cusp indiastole, termed “effective height” (eH), and by thedistance of the curved length of the respective cuspduring diastole from the aortic insertion in the nadirof the sinus to the central part of the free margin,termed “geometric height” (gH). The coaptation ofthe cusps is also defined by coaptation length (i.e.,the height of adjacent cusp tissue in diastole). Normalcoaptation length is about 2 to 5 mm (29–33).

ECHOCARDIOGRAPHIC ASSESSMENT

OF ANATOMY OF THE AV AND

AORTIC ROOT COMPLEX

The main advantage of echocardiography in assessingthe AV and aortic root is live recording in a blood-pressurized dynamic state. Functionality of the AVcan be documented in real time by sectional planeviews, en face surface views from the left ventricularoutflow tract (LVOT) and from the tubular ascendingaorta (TAA). In contrast, the surgeon can only seefrom the ascending aorta and must assess AV andaortic root geometry in a nonpressurized state.Because cardioplegia may have an impact onanatomic muscular dimensions, echocardiography issuitable for predicting the presumably best di-mensions of the basal ring and aortic root for suc-cessful AV repair to prevent postsurgicalcomplications.

In clinical practice, conventional 2-dimensional(2D) TTE and 2D TEE are used to assess the anatomyof the AV and aortic root in the parasternal long-axisand short-axis views of the AV (10,34,35). The mainproblem of this conventional 2D approach is often themisleading underestimation of dimensions of theaortic root complex and overestimation of aortic wallthickness due to oblique sectional planes. The LVOT,aortic root, and TAA often cannot be visualized in 1centrally located long-axis view. Thus, 2D echocar-diography is limited because of the pre-definedorientation of the sectional planes, which can beovercome by 3D echocardiography, as shown inFigure 1. Postprocessing of 3D datasets of the AV andaortic root enables accurate sectional planes for pre-cise assessment of the anatomy, providing exact andcorrect measurements, as shown in Figures 2 (Videos3, 4, 5, 6, and 7) and 3, and the Central Illustration(Videos 8 and 9). The advantages of 3D echocardiog-raphy compared with 2D echocardiography in theassessment of the AV and aortic root are listed in

http://jaccimage.acc.org/video/2019/0232_VID1.avi










FIGURE 1 Anatomy of the Aortic Valve

Sinotubular (ST-) junctionCrown-like ring of the insertion of the cups between the VA-and ST-junction

Crown-like tips of the commissures between the cuspsCircle with the maximum diameter of the Sinus of ValsalvaVentricular-aortic (VA-) junction = basal aortic annulus

TAAA

B

C

D E

F G

LCA-Ostium

RCA-Ostium

LVOT SinusesTAA

ST junction

ST junction

VA junction

NCC LCC

RCC

VA junction

LVOT

NCC LCC

RCC

Sinuses

Nadirs of the cusps

Sketches of the aortic valve (AV) and aortic root in a central long-axis view: long-axis (LAX) (A) and transesophageal short-axis (SAX) view (B)

as well as a three-dimensional (3D) sketch of the aortic root (C) illustrating normal aortic complex anatomy. Three-dimensional trans-

esophageal echocardiographic illustrations of the aortic valve and aortic root complex during systole (D, SAX; e, LAX) and diastole (F, SAX; G,

LAX) (see Videos 1 [SAX] and 2 [LAX]). The nomenclature of the distance parameters and characteristic structures are labeled by white

arrows. LCA ¼ left coronary artery; LCC ¼ left coronary cusp; LVOT ¼ left ventricular outflow tract; NCC ¼ noncoronary cusp; RCA ¼ right

coronary artery; RCC ¼ right coronary cusp; ST ¼ sinotubular; TAA ¼ tubular ascending aorta; VA ¼ ventricular-aortic.

J A C C : C A R D I O V A S C U L A R I M A G I N G , V O L . - , N O . - , 2 0 1 9 Hagendorff et al.- 2 0 1 9 :- –- 3D Echocardiography in Aortic Valve Repair

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Table 1. The volume size of the pyramid with theanatomic structures of interest must be as small aspossible to achieve optimal image quality. Startingthe 3D transthoracic or 3D transesophageal echocar-diographic acquisition, the depth and elevational andazimuthal planes are normally adjusted in biplanemodes before the 3D volume is acquired. It is highlyrecommended to acquire the 3D full volume in amultibeat fashion to optimize spatial and temporalresolution. In contrast, it is not recommended tomanually increase the rate of volumes, because of thesignificant consecutive impairment of the spatialresolution by the reduction in simultaneous ultra-sound beams. Cardiac structures should also be ac-quired in a 3D dataset with respect to the best spatialresolution in the axial direction and concerningoptimal reflection of the ultrasound beams. Inparticular, direct 3D visualization of the cusps during

diastole often fails because of the lower lateral andelevation plane resolution, which reflects the dis-tance of the scan lines in parallel to the closed cusps.Most anatomic details can be determined by 3Dechocardiography despite its limitation of lowerspatial and temporal resolution in comparison with2D echocardiography. Normal values of the anatomicdimensions of the left ventricle, the AV, and theaortic root have been recently defined (34–38). It maybe assumed that inner edge–to–inner edge (I-I) mea-surements using 3D echocardiography correspondwith I-I measurements from other imaging modalitiesbecause of the comparable resolution of 3D TEE incomparison with cardiac magnetic resonance imagingand computed tomography (39). Thus, 3D echocar-diographic measurements may be determined usingthe I-I method despite the actual 2D echocardio-graphic recommendations’ focus on the leading edge–



CENTRAL ILLUSTRATION Summary of the Advantages of Applying the 3-DimensionalTechnique to Analysis of the Aortic Valve and Aortic Root Complex Prior to Surgical Correction

TAAA B C

ST junction

Sinuses

VA junction

LVOT

NCC LCC

RCC

Sinotubular (ST-) junctionCrown-like ring of the insertion of the cups between the VA-and ST-junctionNadirs of the cuspsCrown-like tips of the commissures between the cuspsCircle with the maximum diameter of the Sinus of ValsalvaVentricular-aortic (VA-) junction = basal aortic annulus

D

G H I

K

L M

N O

E F

Hagendorff, A. et al. J Am Coll Cardiol Img. 2019;-(-):-–-.

Sketches of the aortic valve (AV) and aortic root: (A) long-axis view, (B) short-axis view, and (C) three-dimensional (3D) view. Parameters

such as diameter of the ventricular-aortic (VA) junction, aortic root, and sinotubular (ST) junction as well as effective height (eH) and

geometric height (gH) of each cusp can be more objectively and accurately assessed using 3D echocardiography than 2-dimensional echo-

cardiography. Labeling of the essential parameters in 3D long-axis view (D), 3D short-axis view of the AV (E), and VA junction (F). Example

illustration of the adjustment of the correct sectional plane of the VA junction (G to I). Example illustration of the adjustment of eH

(yellow) and coaptation length (CL) (blue) between noncoronary cusp (NCC) and right coronary cusp (RCC) and of gH (red) of the RCC.



4

FIGURE 2 Assessment of Aortic Root Diameter by 3-Dimensional Echocardiography

LVOT

A B C D E

F G H I J

K L M N O

P Q R S T

VA-Junction ST-Junction TAASinuses

Illustration of short-axis views of the left ventricular outflow tract (LVOT) (A, F, K, and P; Video 3), ventricular-aortic (VA) junction (B, G, L, and Q; Video 4), sinuses of

Valsalva (C, H, M, and R; see Online Video 5), sinotubular (ST) junction (D, I, N, and S; Video 6), and tubular ascending aorta (TAA) (E, J, O, and T; Video 7) in a 3D TEE

dataset. The first series (A to E) displays the transverse long-axis view of the aortic root perpendicular to the sectional short-axis plane, labeled by white arrows. The

second series (F to J) shows the corresponding short-axis views. The third series (l to O) displays the corresponding horizontal perpendicular long-axis view of the

aortic root. The fourth series (P to T) displays the corresponding 3-dimensional en face view against the bloodstream. The asterisks label the center of the respective

cardiac structure in the short-axis views.


5

to–leading edge measurements (37,38). Measure-ments of the characteristic anatomic structures mustbe performed with respect to their alterations atdefined time points. The sizes of the LVOT, AVannulus, sinus of Valsalva (SoV), STJ, and TAA will belarger to a variable degree in systole, which can beexplained by the maximal stretching of the cardiacstructures during systole. The sizes of the aorticannulus and root are influenced by inner pressureand dynamically change during the cardiac cycle by12% and 16%, respectively (11,28,35,40–42). Thus,there is a rationale to determine the maximum dis-tances of these parameters in midsystole using 3Dechocardiography, especially in patients with AR, inwhom the differences in these distances are large

because of large cardiac dimensions and high regur-gitant volumes (Figure 2, Table 1). The aortic annulusis generally more circular in systole and more ellipticin diastole. In general, it is actually recommended todocument the elliptic shape of the LVOT and AVannulus in short-axis views, the dimensions of the AVannulus and the aortic root in long- and short-axisviews, and the coaptation length during end-diastole (36,37,41,42). In addition, the functionalassessment of the aortic root complex should includethe size alterations between systole and diastole andthe angle difference between mitral and aorticannulus within the cardiac cycle (11,42).

Cusp size and configuration must be determined indiastole, as shown in Table 1. The echocardiographic






FIGURE 3 Illustration of the Adjustment of the Ventricular-Aortic Junction in a Three-Dimensional Transesophageal Echocardiographic Dataset

ANCC

NCC

LCC

RCC

RCC RCC

RCC

LCCNCC

CommissurebetweenNCC and LCC

Commissurebetween LCCand RCC

CommissurebetweenNCC and RCC

LCC

C

B D

E

F

G I

H

En face view of the aortic valve (A; Video 8) during systole from the aorta (yellow arrow in B). The centerlines of each cusp are labeled by white lines. The nadir of each

cusp is at the respective ventricular-aortic (VA) junction. En face view of the VA junction (C; Video 9) during systole from the aorta (yellow arrow in D). The short-axis

views in E and H represent the sectional plane of the VA junction with the labeling of the centerlines of the right coronary cusp (RCC) and the noncoronary cusp (NCC)

(E) and of the RCC and the left coronary cusp (LCC) (H). The corresponding long-axis view documents the nadir of the RCC (right arrow) and the tip of the commissure

between the NCC and the LCC (right arrow) (F). The horizontal sectional plane in G documents the nadir of the NCC (right arrow) and the tip of the commissure

between the LCC and the RCC (right arrow). The horizontal sectional plane in I documents the nadir of the LCC (right arrow) and the tip of the commissure between

the NCC and the RCC (right arrow).



6

parameters of cusp configuration, coaptation length,eH, and gH (23–26) must be determined in diastoleusing specific sectional planes constructed by post-processing in 3D datasets, as illustrated Figures 4 to 6and Table 1. Coaptation can be accurately assessed by3 coaptation lengths between the right and non-coronary cusps, the noncoronary cusp and left coro-nary cusp, and the left and right coronary cusps usinga sectional plane near the central point of the AVbetween the respective 2 cusps, as illustrated inTable 1 by postprocessing in a 3D dataset. In the samemanner, the eH parameter should be described by 3eHs (i.e., 1 for each cusp) (Figure 4, Video 11, Table 1).The gH parameter is impossible to measure correctly,

even of the right coronary cusp, using 2D echocardi-ography because a plane orthogonal to the centralpart of the cusp is required for assessment (Figure 5,Videos 12 and 13). Alignment of these sectional planesfor each cusp can only be made correctly using 3Dechocardiography (Figure 6, Video 11). In patientswith bicuspid AV and quadricuspid valves, coaptationlength and eH must be determined perpendicular tothe commissures near the central point of the AV(Central Illustration), and gH must be measured in asectional plane orthogonal to the central part of eachcusp (Central Illustration) (31).

Three-dimensional echocardiography can objec-tively characterize the height of the crown tips







TABLE 1 Illustrations of the Anatomic Structures and the Parameters Determined by 2- and 3-Dimensional Echocardiography With Comments on the Advantages

and Disadvantages of the Echocardiographic Techniques

AnatomicStructure/Parameter

2D EchocardiographicScheme and 2D Image

3D Echocardiographic Simultaneous Sectional PlanesWithin the 3D Dataset: En Face Views

Comments:Advantages/Disadvantages

Diameter of theLVOT*

Accurate adjustment of theperpendicular sectionalplanes for measurement ofLVOT diameter is possibleonly by 3Dechocardiography.

Reference values: men, 2.6 �0.3; women, 2.3 � 0.2 (37).

Area of theLVOT*

The correctness of the 2Dsectional planes formeasurements of the LVOTarea cannot be controlled.Accurate adjustment of theperpendicular sectionalplanes for measurement ofLVOT area is possible only by3D echocardiography.

Diameter ofthe VAjunction ¼virtual basalring*

Accurate adjustment of theperpendicular sectionalplanes for measurement ofAV junction, which isdetermined by the nadirs ofall 3 cusps in a normal aorticvalve, is possible only by 3Dechocardiography.


Continued on the next page


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TABLE 1 Continued





Area of the VAjunction ¼virtual basalring

Accurate adjustment of thesectional plane of all 3 nadirsfor measurement of the VAjunction area is possible onlyby 3D echocardiography.

Diameter of thesinus ofValsalva*

The adjustment of theperpendicular sectionalplanes for measurement ofthe diameter of the sinusesof Valsalva can be performedonly using 3Dechocardiography.


Diameter of theSTJ*

The correctness of the 2Dsectional planes formeasurements of the STJcannot be accuratelycontrolled. The diameter ofthe STJ can be adequatelyassessed only using 3Dechocardiography.





8

TABLE 1 Continued





Diameter of theproximalTAA*

Accurate adjustment of sectionalplanes perpendicular to thecentral axis of the proximalascending aorta for thecorrect measurement of thediameter of the TAA can beperformed only using 3Dechocardiography.


CL at thecentralpoint of AV*

Accurate adjustment of theperpendicular sectionalplanes for measurement ofthe CL at the central point ofthe AV in diastole is possibleonly using 3Dechocardiography.



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parallel to the plane of the basal ring to clarify thenumber of cusps. The AV cusps must be differenti-ated between unicuspid, bicuspid, tricuspid(normal), and quadricuspid valves, as shown in Ta-ble 1, corresponding to the number of normalcommissures.

Three-dimensional echocardiography is limited bythe prerequisite of an adequate acoustic window, theabsence of severe calcifications because of shadow-ing, the presence of arrhythmias (e.g., atrial fibrilla-tion), and the necessity of image optimization. Ifimage quality of 2D and 3D echocardiography is notsufficient, alternative and additive modalities such ascardiac magnetic resonance imaging and computed

tomography should complement assessments of theAV and aortic root complex.

ASSESSMENT OF AV ABNORMALITIES

With respect to the implications of AV-sparing sur-gery, AV and aortic root morphology and functionmust be systematically assessed using 2D and 3Dechocardiography. The superiority of 3D echocardi-ography comparedwith 2D echocardiography is shownin Table 1. Morphologic changes of the cusps, such ascalcification, prolapse, billowing due to redundanttissue, and fenestrations, are significant and influencethe strategy of the surgeon (43,44). Billowing of the

TABLE 1 Continued





eH betweenRCC and theLCC or NCC*

On 2D echocardiography only,the eH between the RCC andthe LCC or NCC can only bedetermined depending onthe correct orientation of thecommissures. To distinguishbetween LCC and NCC,biplane scanning is necessary.Accurate adjustment of theperpendicular sectionalplanes for measurement ofeach eH in diastole is possibleonly using 3Dechocardiography.

eH betweenNCC andRCC, LCCand RCC,and LCC andNCC*

Accurate determination of eacheH between the respectivecusps in diastole is possibleonly using postprocessing in3D datasets.

Coaptationdistance ofthe adjacentcusps*

The correctness of maximumcoaptation distance betweenthe respective cusps cannotbe controlled in 2D sectionalplanes, even if biplanescanning modalities are used.Accurate adjustment of thesectional plane perpendicularto the adjacent cusps indiastole by 3Dechocardiography isnecessary to assessmaximum coaptationdistance.




10

TABLE 1 Continued





LH LH should be measured on 2Dechocardiography duringend-diastole in the short-axisview from the internal aorticroot border to the free edgeof the so-called leaflet. If thisparameter is measured, asectional plane parallel tothe basal ring must bechosen using 3Dechocardiography. LH istotally different from eH.

LL and LD LL over the belly of the leaflet isa calculated parameter,which corresponds to thehalf perimeter of the ellipsedescribed by the average LHas major axis and twice LD asminor axis. LD is measured inthe long-axis view as thedistance between the linefrom the leaflet insertion tothe leaflet tip and the mostconvex point of the leaflet. Itis possible to measure LL foreach cusp using 3Dechocardiography. However,LL is totally different fromgeometric height.

Leaflet area Leaflet area is also a parametermeasured using 2Dechocardiography duringend-diastole in the short-axisview. On 3Dechocardiography, this areacan be determined exactlyparallel to the basal AVannulus. This parameter wasused in conventionalechocardiography tocharacterize cusp size.



11

TABLE 1 Continued





Cusp-to-cuspdistance*

Cusp-to-cusp distance must bemeasured at the level of thecusps during diastole exactlyin a sectional plane parallelto the basal AV annulus tocharacterize symmetry of theaortic root. The exactorientation of this sectionalplane can be controlled onlyby 3D echocardiography.

Orientationof thecommissurein bicuspidAV*

The impression of the orientationcommissure can varybetween diastole and systoleas well as with respect to thesectional plane. The en face-view or the sectional planethrough the cusps duringdiastole must be exactlyparallel to the plane of thebasal AV annulus, which canbe controlled only by 3Dechocardiography.

*Relevant findings and mandatory parameters for the assessment of the AV–aortic root complex according to our experience.

2D ¼ 2-dimensional; 3D ¼ 3-dimensional; CL ¼ coaptation length; eH ¼ effective height; LCA ¼ left coronary artery; LCC ¼ left coronary cusp; LD ¼ leaflet depth; LH ¼ leaflet height; LL ¼ leaflet length;LVOT ¼ left ventricular outflow tract; NCC ¼ noncoronary cusp; PV ¼ pulmonary valve; RCA ¼ right coronary artery; RCC ¼ right coronary cusp; RVOT ¼ right ventricular outflow tract; STJ ¼ sinotubularjunction; TAA ¼ tubular ascending aorta; TEE ¼ transesophageal echocardiography; TV ¼ tricuspid valve; VA ¼ ventricular-aortic.



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cusps into the LVOT in diastole is the consequence ofredundant cusp tissue if normal AV function is pre-sent. Protrusion of the free margins of the cusps intothe LVOT in diastole with the occurrence of AR isdefined as cusp prolapse. A prolapse is commonlyconsidered to be misalignment of the cusp resulting indeflection of a free cuspmargin toward the LVOT at AVclosure with subsequent AR. A flail cusp is describedby complete eversion of the free edges documented inlong-axis views of the AV (Table 1). If the free margins

of the aortic cusps are stretched or restricted fordifferent causes, valvular incompetence due to teth-ering should be described (Table 1). Cusp retractiondue mainly to fibrosis, calcification, and cusp perfo-ration also leads to abnormal cusp function. Attach-ment, alignment, and fusion of the commissures,central commissural point, and intercommissuraldistances should optionally be determinedwith a viewto potential surgical treatment (Table 1). Additionalcusp parameters determined using short-axis views

FIGURE 4 Illustration of the Assessment of Coaptation Length and Effective Height

A

eH: NCCvs LCC

LCC

RCC

LCC

RCC

NCC

CL

eH

eH

CL

CL

eH

eH: LCCvs RCC

eH: NCCvs RCC

B C D

E F G

H I K

NCC

Measurements should be taken between the respective cusps of a normal tricuspid aortic valve (A; 10) at the inner third of each commissure in the correct adjusted

sectional plane. The orthogonal sectional planes through the center of the aortic valve (Video 11) must be adjusted perpendicular to the commissures between 2

respective cusps. Coaptation length (CL) and effective height (eH) between the noncoronary cusp (NCC) and the left coronary cusp (LCC) (B to D), CL and eH between

the LCC and the right coronary cusp (RCC) (E to G), CL and eH between the NCC and the RCC (H to K).


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during diastole have been described, such as the so-called leaflet area, the area of each cusp determinedin a short-axis view; leaflet height, the maximum dis-tance between the central point of the cusp coaptationand the aortic root determined in a short-axis view;and leaflet length, calculated using leaflet height andleaflet depth, which is the distance between the linefrom the cusp insertion to the cusp tip and the mostconvex point of the cusp determined in a long-axisview (18,27).

In patients with bicuspid AV, cusp fusion, presenceof a true bicuspid AV, or complete or incomplete ra-phes and the circumferential orientation of the com-missures may vary between 180� (symmetrical) andclose to 120� (Table 1).

ANALYSIS OF AR MECHANISMS

AR may be caused by abnormalities of the AV itself,aortic root, or a combination of both (1,10,27,45–47).Regurgitant jet morphology is influenced by cusp

morphology. Dilation of the aortic annulus orenlargement of the aortic root will cause incompletecusp closure, mostly in the center of the AV withcentral regurgitant jet formation. Cusp prolapse andcusp flail result mostly in eccentric aortic jet forma-tion. Fenestrations and indentations will normallycause asymmetrical spraying jet formations. ARseverity should be determined quantitatively byregurgitant fraction or semiquantitative parameters(e.g., effective regurgitant orifice area) (1,47) (Table 1).Dilation of the basal ring is frequently seen in sig-nificant AR. To what degree annular dilation alonecan contribute to AR remains unclear. Epidemiologi-cally, the most frequent cause in AR is aortic dilata-tion (45). Dilation of the STJ appears to be the majorcomponent leading to regurgitation. Whether isolateddilatation of the sinus portion of the root will lead toregurgitation it is not known. Patients may exhibitmore than 5 cm of sinus diameter without significantAR. Maximum diameters of the LVOT, ventricular-aortic junction, SoV, STJ, and proximal TAA should


FIGURE 5 Illustration of the Intersection Points of Coronary Cusps With the Ventricular - Arterial Wall

A

F G H I

SystoleDiastoleSystoleDiastole

RCC

TTE TEE

LCCNCC

RCC

LCCNCC

RCC

LCCNCCRCC

LCCNCC

B C D E

Right coronary cusp- RCC

Left coronary cusp- LCC

Non coronary cusp- NCC

Intersection of the coronary cusp with the ventricular-aortic junction in sketch (A) and on 2-dimensional (2D) transthoracic echocardiography (TTE) (B and C, sketches in

F and G; Video 12) and 2D transesophageal echocardiography (TEE) (D and E, sketches in H and I; Video 13) echocardiography. The right coronary cusp (RCC) is

intersected at the hinge point. The crown tip of the commissure between the left coronary cusp (LCC) and noncoronary cusp (NCC) is intersected at the opposite part of

the aortic valve.



14

be measured using 3D TEE during midsystole (Ta-ble 1). The surgical strategy for isolated AV recon-struction depends on exact and objectiveechocardiographic aortic root assessment in patientswith AR, which is standardized only by 3D echocar-diography. The normal size of the aortic root ischaracterized by a 15% to 20% larger diameter of theSTJ than of the basal ring (13,20). Enlargement of theaortic root with normal aortic cusps is often docu-mented by disappearance of the STJ and direct tran-sition of the SoV to the proximal TAA, a ratio of theSTJ to the ventricular-aortic junction >1.5, andcoaptation height with tenting of the cusp of >11 mm(29,30,32). Rotational and translational movements

can be considered for reliable measurements of theaortic root using 3D echocardiography. Aortic annularexcursion during the cardiac cycle is about 13 � 2 mmand contributes to efficient cardiac output. In addi-tion, the angle between the mitral and aortic annuluschanges between systole and diastole.

A root mechanism leading to AR, which is unre-lated to dilation, must be anatomically linked toinvolvement of AV commissures. This is typical inaortic dissection (1,45). Asymmetry of the aortic rootcan induce commissural displacement and cusp sep-aration because of cusp restriction. Asymmetry can bedescribed when the largest cusp-to-cusp distanceis $5 mm from the smallest cusp-to-cusp distance



FIGURE 6 Illustration of the Assessment of Geometric Height

A

gH: NCCLCC

LCC

NCC NCC

gH: LCC

gH: RCC

B C D

E F G

H I K

RCCRCC

Measurements should be taken in a normal tricuspid aortic valve (A; Video 10) at the central sectional plane of each cusp, respectively. Geometric height (gH) of the

right coronary cusp (RCC) (B to D; Video 11), gH of the left coronary cusp (LCC) (E to G), and gH of the noncoronary cusp (NCC) (H to K).


15

(Table 1). The second component of AR is cusp dis-ease, mainly cusp restriction, retraction, or prolapse.Restriction may be caused by shrinking of cusp tissueor calcification (Table 1). Cusp prolapse is oftencaused by myxomatous degeneration, with elonga-tion of the cusp caused or aggravated byfenestrations.

ASSESSMENT OF AV REPARABILITY AND

RESULTS OF AV REPAIR

In patients with severe AR and with significant aorticroot dilation, surgical repair is actually recommendedif possible (45). AV reparability depends strictly oncusp morphology and aortic root dimensions. In pa-tients with central AR and noncalcified cusps, suffi-cient AV function can often be restored by reductionin aortic root dimensions (AV-sparing root replace-ment techniques). In patients with eccentric AR cupmorphology, the amount of cusp tissue determine theoptions for reparability. Three-dimensional echocar-diography, especially TEE, enables measurements ofall AV and aortic root structures with definedsectional planes by postprocessing in a 3D dataset.

Thus, bellies, free margins, and coaptations of allcusps can exactly be assessed, as shown in Table 1.Analysis of the morphology and function of the AVand aortic root is crucial prior to surgical interven-tion, because normalization of aortic root dimensionsand restoration of cusp configuration are pre-requisites for successful AV repair. The eH parameterhas a nearly constant relationship with root dimen-sion and body size. The surgical normalization of eHlarger than 8 mm is in line with a high probability ofnormal AV function (30,33). For normal AV functionafter AV repair, a normal amount of cusp tissue is animportant prerequisite characterized by gH. Basalannular and root dimensions must be normalized byAV repair in relation to the assumed complete coap-tation of the AV during diastole, which can beassessed by the optimal target dimensions of thebasal annulus, coaptation length, and eH after treat-ment. Thus, it is important to assess the eH parameteras well as diameter of the aortic root to evaluate theeffectiveness of AV repair immediately after surgery.In cusp prolapses, the degree of protrusion of cusptissue into the LVOT is used for quantification of thecusp prolapse. Whereas normal coaptation between



HIGHLIGHTS

� Reconstructive surgery of the aorticvalve has currently received increasingattention in patients with aortic regurgi-tation and/or aortic aneurysm.

� The use of 3D echocardiography is apowerful tool to objectively characterizedifferent forms of aortic valve and rootabnormalities and to define echocardio-graphic predictors of successful valve/root complex repair.

� The systematic analysis of the aortic rootby 3D echocardiography enables correctplanning of surgical procedures inreconstructive surgery in patients withaortic regurgitation and aortic valve/rootabnormalities.

� Automatic quantification of the aorticroot complex and image optimization byfurther technical improvements willfacilitate the dynamic analysis of theaortic root complex by echocardiographyin the future.



16

the cusps is documented by positive eH, the protru-sion of the cusp margin caudal to the basal annulusinto the LVOT is documented by negative eH.

Assessment of cusp configuration and geometry bydetermination of intercommissural distance,commissural orientation, length of cusp insertion,amount of cusp tissue, and length of the free marginis essential prior to cusp repair for estimation of post-operative status after AV repair. Aortic root di-mensions affect cusp geometry and should benormalized, targeting a ratio between STJ diameterand AV junction diameter >1.2 (2,8,14,15,22). Accu-racy of pre- and post-surgical measurements can beimproved markedly by 3D echocardiography in com-parison with 2D echocardiography with respect to theoptimal alignments of representative sectional planeswithin the 3D datasets (19,20,27). The expectedoptimal post-operative result should be documentedby a flexible valve without residual regurgitation orsignificant restrictive opening and with a nondilatedascending aorta. Thus, several features should againbe analyzed by 3D echocardiography after surgery.The level of cusp coaptation should be above theaortic annulus; if coaptation occurs below theannulus, the risk for recurrent AR is >70%. The heightof coaptation should be >9 mm and reach the middleof the SoV. In patients with residual AR, the length ofcusp apposition should be <4 mm to avoid recurrentsevere AR in follow-up (30% to 40%). If AV repairreduces the valve orifice area, mean aortic gradients>15 mm Hg are associated with an increased risk fordeveloping aortic stenosis. If the repair is unsatis-factory because of the aforementioned criteria, thedecision to review or replace the valve depends onthe underlying mechanism of AR, quality of the valvetissue, and other patient risk factors, such as old age,comorbidities, and left ventricular function.

FINAL RECOMMENDATIONS ACCORDING TO

THE AUTHORS’ EXPERIENCE AND THE

PUBLISHED RESEARCH

The results of echocardiographic measurements ofthe AV and aortic root depend strongly on the timepoint of the cardiac cycle. The maximum anterior-posterior diameter of the LVOT, AV annulus, SoV,STJ, and TAA obviously vary between systole anddiastole (35,42,48). These dimensions are larger dur-ing systole than diastole, especially in younger pa-tients with preserved compliance of the aortic root.These dimensions are important for decision makingin AV reconstruction, which is generally performed inyounger patients. Given these considerations, webelieve strongly that AV complex measurements

should be performed in midsystole. In addition,spatial resolution of the external aortic wall using 3DTTE and 3D TEE may be limited. Because of superiordemarcation of the inner aortic wall, especially using3D TEE, we believe that I-I measurements are supe-rior to leading edge–to–leading edge measurementswhen using 3D echocardiography. Finally, underes-timation is unavoidable on 2D TEE for the reasonsstated. Thus, correct determination of these impor-tant diameters can best be achieved by I-I measure-ments during midsystole using standardizedsectional planes within the 3D datasets bypost-processing. This creates a contradictionregarding proposed midsystolic measurements andcurrent guideline recommendations (36,37,41). Cur-rent guidelines, however, do not address the specificaspects of AV repair. Furthermore, several studiesshowed that using the I-I convention, underestima-tion was compensated for by measuring aortic di-ameters at mid-end-systole (49,50). Measurements ofcusp morphology and geometry, especially CL, eH,and gH, obviously must be performed during diastole,when the cusps are stretched by diastolic pressure.All findings and parameters for the assessment of theAV–aortic root complex that are relevant andmandatory according to our experience are high-lighted in Table 1.


17

SUMMARY

Three-dimensional echocardiography is the best im-aging technique for patient selection for surgical AVrepair and AV-sparing surgery. Two-dimensional TTEand 2D TEE are inferior to 3D echocardiographybecause of misleading measurements in non-standardized, oblique sectional planes. Three-dimensional echocardiography should includeanalysis of AV morphology, aortic root dimensions,and AR severity. Cusp morphology and commissuresand measurements of coaptation length, eH, and gHparameters should be described in a systematicapproach using mainly 3D TTE and 3D TEE. Complete

and concise analysis using 3D echocardiography en-ables correct decision making and planning of surgi-cal procedures in patients with AR and AV and aorticroot abnormalities. It can be assumed that automaticquantification of the aortic root complex will facili-tate the dynamic analysis of the aortic root complexin the future.

ADDRESS FOR CORRESPONDENCE: Prof. Dr. Med.Andreas Hagendorff, University Hospital of Leipzig,University of Leipzig, Department of Cardiology,Liebigstrasse 20, 04103 Leipzig, Germany. E-mail:[email protected].

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KEY WORDS 3D echocardiography, aorticregurgitation, aortic root, aortic valve repair

APPENDIX For supplemental videos,please see the online version of this paper.


































































































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