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ORIGINAL ARTICLES: ADULT CARDIAC

ADULT CARDIAC SURGERY:The Annals of Thoracic Surgery CME Program is located online at http://cme.ctsnetjournals.org.To take the CME activity related to this article, you must have either an STS member or anindividual non-member subscription to the journal.

Saddle-Shape Annuloplasty Increases Mitral LeafletCoaptation After Repair for Flail Posterior Leaflet

Mathieu Vergnat, MD, Benjamin M. Jackson, MD, Albert T. Cheung, MD,Stuart J. Weiss, MD, PhD, Sarah J. Ratcliffe, PhD, Mathew J. Gillespie, MD,Y. Joseph Woo, MD, Joseph E. Bavaria, MD, Michael A. Acker, MD,Robert C. Gorman, MD, and Joseph H. Gorman III, MD

Gorman Cardiovascular Research Group, Departments of Surgery, Anesthesia, Biostatistics & Epidemiology, and PediatricsUniversity of Pennsylvania, Philadelphia, Pennsylvania

1

Background. The primary goal of surgical mitral repair isthe reestablishment of normal leaflet coaptation. Surgicaltechniques that maintain or restore leaflet geometry pro-mote leaflet coaptation. Recent 3-dimensional (3D) echocar-diographic studies have shown that saddle-shaped annulo-plasty has a salutary influence on leaflet geometry.Therefore we hypothesized that saddle-shaped annulo-plasty would improve leaflet coaptation in cases of repairfor flail posterior leaflet segments.

Methods. Sixteen patients with flail posterior segmentand severe mitral regurgitation had valve repair usingstandard techniques. Eight patients received saddle-shapedannuloplasty and 8 patients received flat annuloplasty. Real-time 3D transesophageal echocardiography was performedbefore and after repair. Images were analyzed using customsoftware to calculate mitral annular area (MAA), septo-

lateral dimension (SLD), intercommissural width (CW),

fl

Pennsylvania, 500 S Ridgeway Ave, Glenolden, PA 19036; e-mail:gormanj@uphs.upenn.edu.

© 2011 by The Society of Thoracic SurgeonsPublished by Elsevier Inc

total leaflet area (TLA), and leaflet coaptation area (LCA).Results. Postrepair MAA (flat, 588.6 � 26.5 mm2; sad-

dle, 628.0 � 35.3 mm2; p � 0.12) and TLA (flat, 2198.5 �51.6 mm2; saddle, 2303.9 � 183.8 mm2; p � 0.67) were

similar in both groups. Postrepair LCA was significantlygreater in the saddle group than in the flat group (226.8 �24.0 mm2 and 154.0 � 13.0 mm2, respectively; p � 0.02).

Conclusions. Real-time 3D echocardiography andnovel imaging software provide a powerful tool foranalyzing mitral leaflet coaptation. When compared withflat annuloplasty, saddle-shaped annuloplasty improvesLCA after mitral valve repair for severe mitral regurgita-tion secondary to flail posterior leaflet segment. Use ofsaddle-shaped annuloplasty devices may increase repairdurability.

(Ann Thorac Surg 2011;92:797–804)

© 2011 by The Society of Thoracic Surgeons

Since its inception 40 years ago, surgical mitral valverepair has become progressively more intricate [1].

espite this growing complexity there is still consensushat 3 basic tenets remain fundamental to a successfulepair: remodeling annuloplasty, preservation of mobileeaflet tissue, and restoration of a large surface of leafletoaptation [2, 3]. Some authors propose that the creationf a large area of leaflet coaptation is the primary goal ofhe repair surgeon, with annuloplasty and leaflet preser-ation serving as important tools toward that end [4].Although many techniques have been developed to

pare and mobilize leaflet tissue, little recent attentionas been paid to the influence of annuloplasty on leafletoaptation [4–6]. Relying on surgical intuition and care-

Accepted for publication April 7, 2011.

Address correspondence to Dr Joseph H. Gorman III, Gorman Cardio-vascular Research Group, Glenolden Research Laboratory, University of

ul but qualitative observation, Carpentier and col-eagues [2, 7] proposed early on that ring annuloplasty

optimizes coaptation by restoring more normal annularsize and shape. Although this intuitive assertion is widelyaccepted, little quantitative evidence exists.

The development of quantitative three-dimensional(3D) echocardiographic imaging techniques has ex-panded our understanding of normal mitral annulargeometry [8, 9]. These insights have spawned a newgeneration of saddle-shaped annuloplasty rings de-signed to restore the annulus to its normal 3D geometry.We have shown previously that saddle-shaped annulo-plasty restores or maintains normal annular geometryand in doing so reestablishes more normal leaflet geom-etry [10] and function [11] when compared with flatannuloplasty. Based on this work and Carpentier andcolleagues’ premise, we hypothesized that saddle-shaped annuloplasty promotes a larger area of leafletcoaptation after mitral valve repair. To test this hypoth-

esis we applied real-time 3D echocardiography and novel

0003-4975/$36.00doi:10.1016/j.athoracsur.2011.04.047

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image analysis software to a cohort of patients undergo-ing mitral valve repair for mitral regurgitation secondaryto flail segment of the posterior leaflet.

Patients and Methods

PatientsSixteen patients with severe mitral regurgitation secondaryto a flail segment of the posterior leaflet (P2 in15 patients; P3in 1 patient) underwent mitral valve repair by 4 surgeons.The flail segment was treated by triangular resection, quad-rangular resection, or leaflet inversionplasty (see Table 1 fora summary of repair techniques).

In all cases ring selection was at the discretion of thesurgeon and the study was done retrospectively. In 8patients a Carpentier-Edwards Physio AnnuloplastyRing (flat ring; Edwards Lifesciences, Irvine, CA) wasused. In the other 8 patients a Medtronic Profile 3D

Abbreviations and Acronyms

AA � anterior annulusAC � anterior commissureAH � annular heightAHWCR � annular height to commissural width

ratioAML � anterior mitral leafletAoV � aortic valveCW � commissural widthLA � left atriumLV � left ventricleLVOT � left ventricular outflow tractMAA � mitral annular areaNCA � normalized coaptation areaPA � posterior annulusPC � posterior commissurePML � posterior mitral leafletSLD � septolateral dimensionTLA � total leaflet area

Table 1. Procedure Summary

Saddle Annuloplasty

Flail Segment Surgical Technique Ring Size Surge

P2 Quadrangular resection 28 4

P2 Triangular resection 34 1

P2 Quadrangular resection 32 3

P2 Quadrangular resection 38 1

P2 Triangular resection 32 1

P2 Quadrangular resection 30 1P2 Quadrangular resection 32 4P2 Quadrangular resection 30 4

Annuloplasty System (saddle ring; Medtronic, Minneap-olis, MN) was placed.

The inversionplasties were carried out by grasping theleading edge of the ruptured chordal segment withforceps and inverting it into the left ventricle. Thistechnique moved a triangular piece of posterior leaflettissue below the plane of the mitral valve annulus andpresented 2 opposing short lines of tissue along theresidual P2 segment. These 2 lines were then reapproxi-mated with a double running suture. Static pressuretesting of the ventricle at this point uniformly demon-strated a competent mitral valve. The repair was thenreinforced with a ring annuloplasty, paying attention tosize the ring appropriately to the entire pressurizedmitral valve orifice [12].

The triangular and quadrangular resections were car-ried out using standard Carpentier techniques [13]. Foreach technique a minimum amount of leaflet tissue wasresected and the remaining leaflet edges approximatedand sutured. In all cases of quadrangular resection theannulus was plicated. Repairs were then reinforced withannuloplasty rings that were sized to the anterior leaflet.

All patients underwent real-time 3D echocardiographyfor mitral valve imaging before and after repair. Theprerepair imaging was performed in the operating roomafter induction of general anesthesia and before sternot-omy. The postrepair images were obtained after sternalclosure before leaving the operating room.

The real-time 3D echocardiographic datasets were ac-quired through the midesophageal view with an iE-33platform (Philips Medical Systems, Andover, MA)equipped with a 2- to 7-MHz X7–2t TEE matrix transducer.Electrocardiographically gated full-volume images wereacquired over 4 cardiac cycles during a period of apnea atend expiration. Care was taken to include the mitral appa-ratus in its entirety for the volumetric data during the entireacquisition. The volumetric frame rate was 17 to 30 frames/second with an imaging depth of 12 to 16 cm.

The study protocol was reviewed and approved by the

Flat Annuloplasty

Flail Segment Surgical Technique Ring Size Surgeon

P2 Triangularresection

36 1

P2 Triangularresection

30 1

P3 Triangularresection

32 2

P2 Quadrangularresection

34 2

P2 Quadrangularresection

30 2

P2 Inversionplasty 32 3P2 Inversionplasty 30 3P2 Triangular 32 2

on

resection

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University of Pennsylvania School of Medicine Institu-tional Review Board.

Image SegmentationEach full-volume dataset was then exported to an Echo-View 5.4 (TomTec Imaging Systems, Munich, Germany)workstation for image analysis. Analysis was performedat midsystole and middiastole. The plane of the mitralvalve orifice was rotated into a short-axis view. Thegeometric center was then translated to the intersectionof the 2 corresponding long-axis planes, which thencorresponded to the intercommissural and septolateralaxes of the mitral valve orifice. A rotational templateconsisting of 18 long-axis cross-sectional planes sepa-

Fig 1. Annular segmentation technique. (A) View of the mitral valvevalve. The aortic valve (AoV) and mitral valve orifice (MVO) are indspaced at 10-degree increments and centered at the geometric center othe rotational template of A) of the heart. The left ventricle (LV), leftterior (PML) mitral leaflet, left atrium (LA), aortic valve (AoV), anterin this orientation, the negative z-axis (for purposes of annular heighthe positive z-axis extends toward the left atrium.

Fig 2. Leaflet segmentation technique. (A) Leaflet segmentation usingrior commissure [AC], posterior commissure [PC]). (B) One of the 2Dseptolateral measurement planes, between 5 and 40 individual pointstion of a given measurement plane) on the atrial surface of the mitralrecorded as anterior mitral leaflet (AML), coaptation leaflet (Coapt), omarked with an “●” and the most ventricular coaptation point is martricular coaptation points are then projected onto a viewing plane ortsures to construct a 2D representation of the atrial (•) and ventriculathe coaptation area in this projection. The white and red dashed lines

valve; LA � left atrium; LV � left ventricle; LVOT � left ventricle outflow

rated by 10-degree increments was superimposed on the3D echocardiogram. The 2 annular points intersectingeach of the 18 long-axis rotational planes were thenidentified by means of orthogonal visualization of eachplane; the 2 annular points were marked interactively(Fig 1).

Measurement planes were then marked at fixed 1-mmintervals along the entire length of the intercommissuralaxis (Fig 2A). In each 2D plane, data points delineatinganterior and posterior leaflets were traced across theatrial surfaces resulting in a 500-point to 1000-pointdataset for each valve (Fig 2B). For the coaptation tracing,meticulous care was taken to clearly identify the tip ofboth anterior and posterior leaflets immediately before

e the selected short-axis plane coincides with the plane of the mitral. A rotational template consisting of 18 long-axis planes evenlymitral valve are constructed. (B) Single long-axis view (0 degrees onicular outflow tract (LVOT), anterior mitral leaflet (AML) and pos-A) and posterior (PA) annular points have been marked. Note thatcoaptation height calculations) extends toward the apex, whereas

verse cross-sections every 1 mm along intercommissural axis (ante--sections represented by the white dashed line in A. In each of thesending on the septolateral diameter of the mitral valve at the posi-e are marked manually (green curves). The position of each point isterior mitral leaflet (PML). The most atrial coaptation point isith an ”x.” (C) Schematic demonstrating how the atrial and ven-al to the least squares annular plane passing through the commis-

coaptation edges. The area bounded by these coaptation lines definesoth within least squares annular plane in A–C. (AoV � aortic

whericatedf theventrior (At and

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coaptation (using previous frames) so that the highest(most atrial) and lowest (most ventricular) margins of thecoaptation zone could be defined. These atrial and ven-tricular edges of the coaptation zone were then markedinteractively (Figs 2B, C). Anterior and posterior commis-sures were defined as annular points at the junctionbetween the anterior and posterior leaflets (middle ofcommissural region) and interactively identified. The X,Y, Z coordinates of each data point, assigned to theannulus, anterior leaflet, posterior leaflet, or the coapta-tion surface, were then exported to Matlab (Mathworks,Inc, Natick, MA).

To assess total leaflet tissue the anterior and posteriorleaflets were imaged again at end diastole using the sametechniques.

Annular AnalysisUsing custom Matlab algorithms (Mathworks Inc ) andorthogonal distance regression, the least squares plane ofthe data point cloud for the annulus was aligned to thex-y plane. Under these geometric conditions, the annularheight for each point (zn) was plotted as a function ofrotational position on the annulus. A number of anatomiclandmarks (Fig 3) were identified. The septum was iden-tified as the anterior horn of the annulus at the aorticvalve, corresponding to zmax. The lateral annulus waslocated at the middle of the posterior annulus circumfer-ence. With the annular model transformed so that thecommissures were aligned with the y-axis, the anterolat-eral and posteromedial annular points were the locationsof maximal and minimal y-value.

Annular height (AH) was defined as zmax – zmin. SLiameter was defined as the distance, in 3D space,eparating the 2 data points S and L. Commissural widthCW) was defined as the 3D distance between the 2ommissures. Annular height to commissural width ratioAHCWR) was subsequently defined as AH/CW � 100%.

itral annular area (MAA) was defined as the areanclosed by the 2D projection of a given annular data setnto its least squares plane.

Fig 3. Annular modeling. Oblique (A), intercommissural (B), and tranmitral annular model. The 36 annular data points (circles) have beenin each view. (A) Distance from least squares plane to given annular(AH) and septolateral (SL) diameter are determined for each valve. (C

terior area; AC � anterior commissure; L � lateral; PA � posterior area; P

The degree of annular undersizing after repair wasalculated as the change in annular area (post-MAA –re-MAA) divided by prerepair MAA and expressed as aercentage.

Coaptation and Leaflet AnalysisUsing interpolation methods, the 3D length of atrial andventricular coaptation edges were determined. The 3Dcoaptation area and diastolic total leaflet area (TLA) werethen determined by triangulating the sampling pointsand summing the areas of the individual triangles.

Because leaflet coaptation area (LCA) is known to bedirectly proportional to TLA and inversely proportionalto annular size, a normalized coaptation area (NCA) wascalculated to reduce between-patient variation in thesepostrepair parameters and to more clearly isolate theinfluence of annuloplasty shape on coaptation area:

NCA � LCA � �MAA ⁄ TLA�To provide a 2D visual representation of the coaptation

area, the atrial and ventricular coaptation edges wereprojected onto a viewing plane orthogonal to the leastsquares annular plane passing through both commis-sures (Fig 2C). Averaged images were then created foreach group using interpolation of a normalized intercom-missural sampling scale. The resulting images were thencentered for comparison.

From these 2D projections, the leaflet coaptation lengthwas calculated at every point from commissure to com-missure and plotted for each group using normalizedintercommissural distances.

All image analysis was done retrospectively.

Statistical AnalysesAll continuous annular and leaflet parameters for the 2groups (Table 1) were compared using either the Kruskal-Wallis rank sum test or the t test, depending on normalityassumptions being met. The central tendency of thesemeasurements is presented as mean � standard error ofhe mean.

ular (C) views of a single real-time three-dimensionally derivedded. The least squares plane has been superimposed on the annulus(zn) is measured for a given data point. (B) Both annular height

ercommissural width (CW) is determined for each valve. (AA � an-

svalvinclupoint) Int

C � posterior commissure; S � septum; zn � regional height.)

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Because of the noncontinuous nature of the annulo-plasty ring, data between group comparisons were de-termined using Mann-Whitney U tests, and the centraltendency was reported as the median.

Overall assessment of leaflet coaptation length and over-all coaptation area shape between groups was carried outusing a mixed effects model to account for the correlationbetween positions inherent in the 2 groups. Subsequentlycoaptation length was compared at each position along theintercommissural line using a Wilcoxon exact test withoutcorrection for multiple comparisons.

For all comparisons, a p value less than or equal to 0.05was considered significant. All statistical analyses wereperformed using Stata 11.0 MP (StataCorp LP, CollegeStation, TX).

Results

AnnulusThe median nominal annuloplasty ring size was 32 ineach group; the full range of ring sizes is presented inTable 1.

Measured and derived annular parameters are sum-marized in Table 2. All values are expressed as mean �

able 2. Annular and Leaflet Data Summary

Annular Parameters Flat Ring Saddle Ring

Prerepair annular height (mm) 7.2 � 0.9 7.5 � 0.6ostrepair annular height(mm)

2.7 � 0.2 7.7 � 0.5a

Prerepair commissural width(mm)

35.3 � 2.1 37.0 � 2.1

ostrepair commissural width(mm)

30.7 � 0.9 33.5 � 1.1

rerepair annular heightcommissural width ratio

20.2 � 1.6 20.5 � 1.6

ostrepair annular heightcommissural width ratio

8.7 � 0.6 22.9 � 1.2a

Prerepair septolateraldimension (mm)

33.7 � 1.6 37.7 � 1.8

ostrepair septolateraldimension (mm)

23.7 � 0.5 23.6 � 0.8

rerepair mitral annular area(mm2)

1228.5 � 99.8 1461.9 � 149.4

ostrepair mitral annular area(mm2)

588.6 � 26.5 628.0 � 35.3

nnular undersizing (%) –50.7 � 2.8 –54.6 � 4.2ostrepair total surface area(mm2)

2198.5 � 151.6 2303.9 � 183.8

ostrepair coaptation (mm2) 154.0 � 13.0 226.8 � 24.0a

Postrepair Coaptation /Diastolic Surface Area

0.07 � 0.00 0.10 � 0.01a

Normalized coaptation area(mm2)

41.2 � 2.7 62.6 � 7.7a

3D atrial coaptation edgelength (mm)

28.4 � 0.8 31.3 � 1.0a

3D ventricular coaptation edgelength (mm)

28.4 � 0.8 31.3 � 1.0a

sa Denotes significant between-group differences (p � 0.05).

standard deviation. Data are presented for the flat ring(n � 8) and saddle ring (n � 8) groups before and afterepair.

Before repair, annular sizes—as assessed by MAA,LD and CW– were similar in both groups. After repair,oth groups’ annular dimensions were significantly butimilarly reduced. After flat annuloplasty, MAA wasiminished by 50.7% � 2.8% and by 54.5% � 4.9% afteraddle annuloplasty (p � 0.40). After repair all measures

of annular size (MAA, SLD, CW) were similar in bothgroups.

Global annular height was maintained after saddleannuloplasty (before, 7.5 � 0.6 mm; after, 7.7 � 0.5 mm)and significantly reduced by flat annuloplasty (before,7.2 � 0.9 mm; after, 2.7 � 0.2 mm; p � 0.00). The

onplanarity of the annulus, as assessed by AHCWR,lso showed a significant decrease after flat annuloplastybefore, 20.2% � 1.6%; after, 8.7% � 0.6%; p � 0.00).HCWR was maintained by saddle-shaped annuloplasty

before, 20.4% � 1.6%; after, 22.9% � 1.2%).

LeafletsTotal postrepair leaflet surface area was similar betweengroups (flat, 2198.5 � 151.6 mm2 versus saddle, 2303.9 �183.8 mm2). The 3D coaptation area was found to beignificantly larger in the saddle annuloplasty group (flat,54.0 � 13.0 mm2 versus saddle, 226.8 � 24.0 mm2; p �

0.02). The fraction of TLA involved in the coaptationregion was also greater in the saddle group (flat, 0.07 �0.00 versus saddle, 0.10 � 0.01; p � 0.00).

Even though there were no significant between-groupdifferences in MAA and TLA, the NCA illustrated themost dramatic between-group differences, with the sad-dle group NCA being more than 50% larger than the flatrepair group (62.6 � 7.7 mm2 versus 42.2 � 2.7 mm2; p �.01).Additionally, both the atrial and the ventricular 3D

oaptation lines were found to be longer in the saddleroup (Table 2).Figure 4 demonstrates a 2D projection of the averaged

eaflet coaptation areas for each group. From this figure itan be seen that the coaptation area and length of thetrial and ventricular coaptation edges of the flat groupre remarkably smaller than those of the saddle group.he relationship of the coaptation lines and commissures

o the annular plane is also illustrated. In the flat ringroup, commissure and coaptation lines are pulled closero the annular plane.

A comparison of leaflet coaptation lengths as a func-ion of normalized intercommissural position is shown inigure 5. Considering all coaptation length measure-ents together, the saddle group had on average coap-

ation lengths that were 1.44 times as long as the flatroup (p � 0.031). The regions where the coaptation

engths were found to be significantly longer in theaddle group are shown by the shaded regions in Figure. The shape of the coaptation area was found to be

imilar in both groups.

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Comment

The primary component of a durable mitral valve repairis the restoration of an optimal area of leaflet coaptation[2, 4]. The word optimal applies to both the size and shape

f the coaptation region. The factors that influence coap-ation are annular size, annular shape, and the amount of

obile leaflet tissue. Surgeons can manipulate the first 2actors by ring annuloplasty and the latter by a growingumber of surgical techniques.The current study takes our understanding of the

nfluence of annuloplasty on postrepair leaflet coaptationiterally to a new dimension. Before our previous work,eestablishment of normal annular geometry referrednly to 2D relationships (ie, the normal systolic 4:3 ratioetween the transverse and anteroposterior annular di-ensions) [7]. During the past decade, using a variety of

imaging modalities we have been able to quantify thenormal saddle shape [9,14,15] of the mitral valve anddocument its importance in optimizing valve perfor-mance [11]. These findings have led to a new generationof saddle-shaped annuloplasty rings. Saddle-shapedrings have subsequently been shown to maintain moreoptimal patterns of leaflet geometry when comparedwith flat rings [10,16,17]. Based on these studies wehypothesized that saddle annuloplasty would have astrong beneficial effect on leaflet coaptation.

Using both previously developed 3D echocardio-graphic techniques [8, 9,18] and the new algorithmsdescribed earlier in this article we were able to demon-strate the positive influence of saddle annuloplasty onleaflet coaptation after repair for flail posterior leaflet.

Fig 4. Comparison of coaptation area. Black curves represent the 2Dprojections of the averaged atrial and ventricular coaptation edgesfor the flat annuloplasty group. The area bounded by the two curvesis the projected 2D coaptation area. The gray curves signify similarparameters for the saddle-shaped annuloplasty group. The repre-sented viewing plane is orthogonal to the averaged best-fit annularplane and passes through the line connecting the anterior (AC) andposterior (PC) commissures. These composite images were createdusing interpolation of a normalized intercommissural sampling scalefor each valve. Dashed lines represent standard deviations. Noticethe larger coaptation area of the saddle group and how the flat ringtends to pull the commissures in a more atrial direction.

Figure 4 is a powerful visual representation of the results.

This figure illustrates the geometry, size, orientation, andrelationship to the annular plane of the coaptation areasof both groups. It can be seen that the flat ring elevates(“atrializes”) the leaflet commissures and in doing soshortens both the atrial and ventricular coaptation edges.

Figure 5 graphically compares leaflet coaptation heightacross the entire coaptation zone in both groups. Thisfigure demonstrates regional heterogeneity in the differ-ence in coaptation length between the 2 groups. Thesaddle ring most profoundly augments coaptation lengthin the region midway between the commissures and thecenter of the valve bilaterally. This figure highlights thestrength of our 3D imaging methodology. The techniqueis not influenced by asymmetry of leaflet closure orasymmetry of coaptation along the mitral valve andtherefore has the potential to overcome many of thelimitations of 2D imaging. The standard evaluation ofleaflet coaptation provided by 2D echocardiography is a1D coaptation length usually obtained as close to thevalve center as possible [19, 20]. Figure 5 demonstratesthat the saddle-shaped ring influences coaptation lengthleast in the middle of the valve. As a result, 2D echocar-diographic imaging directed at this region would havedrastically underestimated the influence of ring shape onleaflet coaptation.

The primary goal of this study was to isolate theinfluence of annuloplasty ring shape on leaflet coaptationarea. Because postrepair total leaflet tissue and annularsize also strongly contribute to leaflet coaptation, varia-tions in operative technique and surgeon preferencewere strong possible confounding variables in this study.Although differences in surgical technique to treat theflail leaflet segment (resection versus inversionplasty)and ring size selection were not controlled for, the novelimaging techniques used provided documentation thatboth repair groups were similar with regard to postrepairTLA and MAA. To further control for the potential

Fig 5. Comparison of coaptation length. Leaflet coaptation lengthversus normalized intercommissural position for both the saddle(gray) and flat (black) annuloplasty groups. Dashed lines representstandard deviations. Shaded areas indicate regions where coaptation

length differed significantly between groups.

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influence of these variables we normalized the coaptationarea to both TLA and postrepair MAA. Interestingly thisNCA parameter demonstrated an even more dramaticdistinction between the 2 groups, lending further supportto the conclusion that there was limited confoundinginfluence due to between-group variation in leaflet tissueor ring size.

Real-time 3D echocardiography is now available inboth transthoracic and transesophageal modalities. Thecombination of this new technology and our novel imageanalysis algorithms provide the tools for quantifying theinfluence of repair techniques on the complex and dy-namic geometry of the mitral valve. Our methodology isnot influenced by viewing plane selection or annulardistortions and therefore represents a potentially useful,clinically relevant, and consistent technique for quanti-tatively assessing mitral valve repair in vivo. With moreclinical experience and longer term follow-up, it mayultimately be possible to correlate parameters such asNCA with repair durability.

This research project was supported by grants from the NationalHeart, Lung and Blood Institute of the National Institutes ofHealth, Bethesda, MD (HL63954 and HL73021). It was alsosupported by an investigator-initiated grant from Medtronic,Minneapolis, MN. Robert Gorman and Joseph Gorman weresupported by individual Established Investigator Awards fromthe American Heart Association, Dallas, TX. Mathieu Vergnatwas supported by a French Federation of Cardiology ResearchGrant.

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3. Adams DH, Rosenhek R, Falk V. Degenerative mitral regur-gitation: best practice revolution. Eur Heart J 2010;31:1958–67.

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midterm results of the “respect rather than resect” ap-proach. Ann Thorac Surg 2008;86:718–25.

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6. Mihaljevic T, Blackstone EH, Lytle BW. Folding valvulo-plasty without leaflet resection: simplified method for mitralvalve repair. Ann Thorac Surg 2006;82:e46–8.

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10. Ryan LP, Jackson BM, Hamamoto H, et al. The influence ofannuloplasty ring geometry on mitral leaflet curvature. AnnThorac Surg 2008;86:749–60.

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INVITED COMMENTARY

The annual rate of recurrent/residual mitral regurgita-tion may reach 2% to 4%, even after repair for a singleprolapsing scallop of the posterior leaflet. The mechani-cal stress and the geometric alterations imposed to theleaflet are important contributors to many instances ofrepair failure that occur after the first postoperative year.With this perspective, saddle-shaped annuloplasty ringshave been reported to restore more efficiently the nativegeometric condition of the valve and optimize leafletstress and force distribution.

The present work from the University of Pennsylvaniagroup [1] introduces two major elements of novelty in

preserves the physiologic nonplanarity angle (in confir-mation of previous animal and computational findings)but also optimizes the coaptation area under the profileof both size and shape, compared with a flat ring.

Second, the improvement in coaptation area associatedwith the saddle-shaped ring is more evident in the para-commissural regions. It is accepted that the restoration ofan optimal coaptation area is a major determinant of repairdurability. Hence, a saddle-shaped ring could guarantee alarger “reserve” in the coaptation area and possibly areduction in the risk of or a delay in the development ofrecurrent regurgitation over the years.

Nonetheless, the pathology of recurrent mitral regur-

0003-4975/$36.00doi:10.1016/j.athoracsur.2011.05.001