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Aortic Valve Repair Using Geometric Ring Annuloplasty

Open AccessPublished:January 13, 2021DOI:https://doi.org/10.1053/j.optechstcvs.2020.11.008
      Reparative operations for insufficient cardiac valves constitute the surgical procedures of choice when pathoanatomies permit. At present, mitral and tricuspid repair techniques are well-established, but recent data also suggest that reconstruction of insufficient aortic valves may be associated with lower operative mortality, fewer valve-related complications, and improved survival. In an effort to increase adoption of aortic valve repair and to mitigate recurrent insufficiency, annuloplasty rings based on normal aortic root geometry have been developed to position in the inflow portion of the aortic annulus similar to mitral and tricuspid rings. This review will describe techniques for tri-leaflet and bicuspid geometric ring annuloplasty, and also will address leaflet reconstruction methods for the common leaflet pathologies. The application of a pathoanatomic approach to aortic insufficiency now permits the majority of aortic valves to be repaired with acceptable clinical outcomes.

      Keywords

      Abbreviations:

      AI (aortic insufficiency), AVr (aortic valve repair), AVR (aortic valve replacement), BAV (bicuspid aortic valve), CT (computed tomography), eH (effective height), FEL (free-edge length), gH (geometric height), TAV (tri-leaflet aortic valve), UAV (unicuspid aortic valve)

      Introduction

      Compared to aortic valve replacement, multiple diverse techniques for aortic valve repair (AVr) for aortic insufficiency (AI) have been associated with lower operative mortality,
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      Mortality characteristics of aortic root surgery in North America.
      fewer valve-related complications,
      • Aicher D
      • Fries R
      • Rodionycheva S
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      Aortic valve repair leads to a low incidence of valve-related complications.
      ,
      • Price J
      • De Kerchove L
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      Risk of valve-related events after aortic valve repair.
      and improved survival for both tri-leaflet (TAV)
      • de Meester C
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      Valve repair improves the outcome of surgery for chronic severe aortic regurgitation: a propensity score analysis.
      and bicuspid valves (BAV).
      • Patlolla SH
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      Bicuspid aortic valve repair:Causes of valve failure and long-term outcomes.
      ,
      • Miyahara S
      • Schneider U
      • Marganthaler L
      • et al.
      Almost) all nonstenotic bicuspid aortic valves should be preserved or repaired.
      Although conversion to a predominant AVr strategy seems in order, existing techniques enable only up to one third of AI valves to be repaired effectively.
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      Long-term outcomes after aortic valve surgery in patients with asymptomatic chronic aortic regurgitation and preserved LVEF: Impact of baseline and follow-up global longitudinal strain.
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      Outcomes in chronic hemodynamically significant aortic regurgitation and limitations of current guidelines.
      In an effort to increase AVr rates, Carpentier's concept of ring annuloplasty was applied to the aortic valve by defining aortic root geometry from human computed tomographic angiograms and then by fabricating annuloplasty rings in the 3-dimensional shape of the normal valve annulus.
      • Rankin JS
      • Bone MC
      • Fries PM
      • et al.
      A refined hemispheric model of normal human aortic valve and root geometry.
      ,
      • Crooke PS
      • Beavan LA
      • Griffin CD
      • et al.
      Design characteristics of a three-dimensional geometric aortic valve annuloplasty ring.
      After 13 years of effort, and over 1000 clinical cases, utilization of geometric aortic ring annuloplasty appears to assist in the successful repair of over 90% of aortic valves with AI.
      • Rankin JS
      • Mazzitelli D
      • Fischlein TJM
      • et al.
      Geometric ring annuloplasty for aortic valve repair during aortic aneurysm surgery: Two-year clinical trial results.
      • Rankin JS
      • Mazzitelli D
      • Fischlein TJM
      • et al.
      Bicuspid aortic valve repair using geometric ring annuloplasty: A first-in-humans pilot trial.
      • Si M-S
      • Conte JV
      • Romano JC
      • et al.
      Unicuspid aortic valve repair using geometric ring annuloplasty.
      This review serves to summarize the basic reparative techniques for AVr using aortic ring annuloplasty.

      Aortic Annuloplasty Rings

      Similar to native annular dilatation associated with mitral regurgitation, most patients with chronic AI have dilated annuli.
      • Jasinski MJ
      • Rankin JS
      • Mazzitelli D
      • et al.
      Leaflet dimensions as a guide to geometric annuloplasty during aortic valve repair.
      The degree of dilatation may depend on the severity and duration of AI, and exceptions may exist for relatively acute insufficiency, such as acute valvular endocarditis. In most patients, however, annular reduction and stabilization by annuloplasty may be a key component of AVr. Based on Carpentier's concept of ring annuloplasty,
      • Carpentier A.
      Cardiac valve surgery—the “French correction”.
      - studies were undertaken to define the geometry of normal TAV and BAV annuli, allowing development of annuloplasty rings that remodel pathologic aortic valve annuli to an appropriate size and shape relative to leaflet dimensions.
      • Rankin JS
      • Bone MC
      • Fries PM
      • et al.
      A refined hemispheric model of normal human aortic valve and root geometry.
      ,
      • Crooke PS
      • Beavan LA
      • Griffin CD
      • et al.
      Design characteristics of a three-dimensional geometric aortic valve annuloplasty ring.
      ,
      • Rankin JS
      • Mazzitelli D
      • Fischlein TJM
      • et al.
      Bicuspid aortic valve repair using geometric ring annuloplasty: A first-in-humans pilot trial.
      ,
      • Rankin JS
      • Dalley AF
      • Crooke PS
      • et al.
      A ‘hemispherical’ model of aortic valvar geometry.
      • Crooke PS
      • Beavan LA
      • Griffin CD
      • et al.
      A geometric model of the normal human aortic root and design of a fully anatomic aortic root graft.
      • Mazzitelli D
      • Pfeiffer S
      • Rankin JS
      • et al.
      A regulated trial of bicuspid aortic valve repair supported by geometric ring annuloplasty.
      A TAV ring is illustrated in Figure 1A, machined from a single block of Titanium and covered with a thin layer of Dacron to promote endothelialization. The shape reflects normal elliptical TAV geometry,
      • Rankin JS
      • Bone MC
      • Fries PM
      • et al.
      A refined hemispheric model of normal human aortic valve and root geometry.
      with a 2:3 minor-to-major axis diameter ratio and 3 equally spaced subcommissural posts, one radius in height, and flaring outward by 10°. The elliptical shape is very important to reduce the anterior-posterior dimension and increase leaflet coaptation. The BAV ring (Fig. 1B) was designed from computed tomographic angiograms before and after successful BAV repair.
      • Rankin JS
      • Mazzitelli D
      • Fischlein TJM
      • et al.
      Bicuspid aortic valve repair using geometric ring annuloplasty: A first-in-humans pilot trial.
      After repair, the bicuspid valves came more into a circular base geometry with 180° commissures, so 180° circular configuration was adapted for the BAV ring. Subcommissural BAV post geometry was adapted from TAV ring, with one base radius in height and a 10° outward flare. More detailed mathematical descriptions of normal human aortic valve and root geometry are provided elsewhere.
      • Rankin JS
      • Bone MC
      • Fries PM
      • et al.
      A refined hemispheric model of normal human aortic valve and root geometry.
      ,
      • Crooke PS
      • Beavan LA
      • Griffin CD
      • et al.
      Design characteristics of a three-dimensional geometric aortic valve annuloplasty ring.
      ,
      • Rankin JS
      • Mazzitelli D
      • Fischlein TJM
      • et al.
      Bicuspid aortic valve repair using geometric ring annuloplasty: A first-in-humans pilot trial.

      Ring Suture Technique

      Like mitral rings, the aortic annuloplasty rings are sutured into the inflow portion of the valve, beneath the aortic annulus. Six to 10 transannular horizontal mattress sutures of 4-0 Teflon-coated braided polyester or polypropylene are placed (Fig. 2A) and tied tightly. The sutures are supported above the valve with fine Dacron pledgets, and the knot towers are fixed laterally with one needle passed into the lateral pledget and aorta, and tied again to prevent leaflet contact (Fig. 2B).
      • Mazzitelli D
      • Pfeiffer S
      • Rankin JS
      • et al.
      A regulated trial of bicuspid aortic valve repair supported by geometric ring annuloplasty.
      Routine use of the lateral fixation technique has dramatically reduced the incidence of early repair failure from both suture-induced leaflet lacerations, and untying of annular sutures.
      • Mazzitelli D
      • Pfeiffer S
      • Rankin JS
      • et al.
      A regulated trial of bicuspid aortic valve repair supported by geometric ring annuloplasty.
      ,
      • Capps SB
      • Elkins RC
      • Fronk DM.
      Body surface area as a predictor of aortic and pulmonary valve diameter.
      Using Cabrol-like mattress sutures, commissural post stitches are placed first, the rings are lowered below the valve, and 1-4 mattress “looping” sutures are placed into each sinus aspect (depending on ring and annulus size). For TAV repair, 2 looping sutures per sinus usually are placed for a total of 9 annular sutures. The exception is the #19 TAV ring, where only 1 looping suture is needed per sinus, for a total of 6 annular stitches. With inherent low gradients, #19 TAV rings are a valuable solution for AI correction in small patients. It is important to place the sutures 2 mm deep to the leaflet aortic junction both above and below the valve, well into the annulus and not into the leaflet. In some bicuspid valves with thick leaflets, it is difficult to discern the leaflet-aortic junction, and intraleaflet placement will ensure abrasion by the ring Dacron and repair failure. It is important to obtain tight contact between the entire annulus and ring, with no gaps or possibility for ring movement, which also can abrade the leaflet tissue.
      It is important to position the tip of the ring post at least 3 mm below the top of the subcommissural triangle (Fig. 2A), which raises the commissural tops relative to the valve base, and increases vertical leaflet coaptation (Fig. 2B). With extensive fenestrations, the posts can be implanted even lower in the triangle, to move the line of leaflet coaptation lower, and below the fenestrations. Again, it is important to make sure the sutures pass well into the annulus (at least 2 mm deep to the leaflet-aortic junction) above and below the valve. Burying the ring posts back into the subcommissural spaces and positioning the sinus aspect of the ring back underneath the annulus mitigates the risk of abrasive contact between leaflet tissue and ring Dacron, which can result in early repair failure. At the end of the implantation, the ring should not be visible from above the valve.

      Ring Sizing Strategy and Orientation

      The rings are produced in 4 sizes: 19 mm, 21 mm, 23 mm, and 25 mm. For the TAV rings, the size number refers to the diameter of a circle with the same circumference as the elliptical ring. Ring size is chosen by measuring the free-edge length (FEL) of all 3 leaflets using special ball sizers positioned in the sinuses (Fig. 3A). For TAV patients with chronic AI, the pathologic annulus is almost always dilated,
      • Jasinski MJ
      • Rankin JS
      • Mazzitelli D
      • et al.
      Leaflet dimensions as a guide to geometric annuloplasty during aortic valve repair.
      and the ring diameter (D) required to optimize leaflet coaptation is determined from the formula: D = FEL/1.5. This concept is based on the observation in human cadaver valves
      • Rankin JS
      • Badhwar V.
      Design of replacement leaflets for the aortic valve.
      that annular diameter of the normal aortic valve is always similar to that of the leaflet-sinus complex, and that the leaflet FEL always subtends half of the leaflet-sinus circumference (hence the 1.5 value reflects π/2). With this unique sizing approach facilitated by ball sizers, the annular dimensions required for appropriate coaptation are determined from the geometry of the aortic valve leaflets instead of the dilated annulus. The final annular dimensions will always reflect ring size rather than including annular tissue thickness.
      Figure 3
      Figure 3Ring sizing strategy and orientation.
      The minor axis post of the TAV ring is positioned under the left-noncoronary commissure (Fig. 3B), consistent with normal anatomy. The 3 leaflets are within 1 size of each other in 95% of patients, and if a one-size discrepancy exists, the smaller size is chosen to downsize the ring. For The TAV rings, liberal downsizing appears to be safe practice. In fact, a small amount of downsizing probably is inherent in this method, which has been highly successful with minimal TAV ring gradients.
      • Mazzitelli D
      • Fischlein T
      • Rankin JS
      • et al.
      Geometric ring annuloplasty as an adjunct to aortic valve repair: Clinical investigation of the HAART 300 device.
      If 3 different leaflet sizes exist (5% of patients), the middle size is selected, and most frequently, no difference from a completely symmetrical valve can be detected. However, the larger leaflet occasionally will prolapse, requiring free-edge plication.
      As described below, downsizing also may be undertaken for primary leaflet prolapse in which leaflet plication may be necessary. The downsizing allows more aggressive leaflet plication without pulling the leaflets out of central coaptation. Downsizing also is used for fenestrations (along with low ring placement) to move the leaflet coaptation line even lower, and for retracted Noduli that may requiring ultrasonic release, to compensate for suboptimal leaflet geometric height.
      As conceived by Schäfers, geometric height (gH) is the radial distance on the leaflet from the annulus to the top of central leaflet coaptation, and effective height (eH) is the vertical distance from the valve base to the top of central leaflet coaptation.
      • Schafers H-J
      • Bierbach B
      • Aicher D.
      A new approach to the assessment of aortic cusp geometry.
      This technique of measuring leaflet FEL is the most objective and effective approach to sizing aortic valve annuloplasty, reducing average annular diameters from 26.5 ± 2.6 mm to 21.7 ± 1.7 mm,
      • Rankin JS
      • Mazzitelli D
      • Fischlein TJM
      • et al.
      Geometric ring annuloplasty for aortic valve repair during aortic aneurysm surgery: Two-year clinical trial results.
      similar to the normal annular diameters observed for the human aortic valve in the Capps study.
      • Capps SB
      • Elkins RC
      • Fronk DM.
      Body surface area as a predictor of aortic and pulmonary valve diameter.

      Central Leaflet Plication

      In some cases, downsizing for asymmetric leaflets may cause the larger leaflet to prolapse slightly, and a small plication stitch can easily correct the prolapse (Fig. 4A). Leaflet plications usually are performed centrally with 6-0 or 7-0 polypropylene sutures, positioned symmetrically on either side of the Nodulus Arantius. One arm of the suture passes from the sinus direction through the lateral Nodulus, and then back through the leaflet free-edge “chord” laterally toward the commissure. This raises the leaflet proportional to the width of the plication and also keeps the Nodulus functioning normally in the midline. Because of the ability to plicate larger cusps, leaflet asymmetry has not been a significant problem in aortic ring annuloplasty. Moreover, it is understood that primary leaflet prolapse occurs in up to 80% of moderate-to-severe chronic AI cases,
      • Mazzitelli D
      • Fischlein T
      • Rankin JS
      • et al.
      Geometric ring annuloplasty as an adjunct to aortic valve repair: Clinical investigation of the HAART 300 device.
      ,
      • Mazzitelli D
      • Stamm C
      • Rankin JS
      • et al.
      Leaflet reconstructive techniques for aortic valve repair.
      and central leaflet plication is an essential method for managing prolapse. As devised by Schäfers et al,
      • Langer F
      • Graeter T
      • Nikoloudakis N
      • et al.
      Valve-preserving aortic replacement: Does the additional repair of leaflet prolapse adversely affect the results?.
      ,
      • Schaefers H-J
      • Aicher D
      • Langer F.
      Correction of leaflet prolapse in valve-preserving aortic replacement: Pushing the limits?.
      central leaflet plication is a major enabling technique for AVr. A completed bi-leaflet plication in a severely prolapsing Sievers Type 0 bicuspid valve is shown in Figure 4B. In Type 0 bicuspid valves, both leaflets have good gH, and no leaflet cleft exists. Therefore, if prolapse is present, only plication of both leaflets is performed, and no cleft closure is needed. It is possible to overplicate, however, especially early in a surgeon's experience. Overplication is manifested in tri-leaflet valves when a pre-repair eccentric AI jet becomes converted to a central jet after unclamping, because overplication pulls the leaflets out of midline coaptation. If this occurs, the aorta is reclamped, and plication sutures are removed until the leaflets become competent. In bicuspid valves, overplication is manifested by increasing systolic gradients, and again, 1 or 2 plications can be removed to reduce the gradient to acceptable levels. Additionally, with experience, a sight picture of proper plication develops, and these problems are less frequently encountered. In tri-leaflet valves, overplication also may be prevented by downsizing annuloplasty ring diameter at the beginning, if it seems significant plication will be necessary.
      Figure 4
      Figure 4Central leaflet plication. Sievers type 0 bicuspid valve with dilated annulus and severe bi-leaflet prolapse.

      Ultrasonic Nodular Release

      Occasionally, additional leaflet procedures may be required, such as Nodular release, as first described by Duran.
      • Duran CMG
      • Alonso J
      • Gaite L
      • et al.
      Long-term results of conservative repair of rheumatic aortic valve insufficiency.
      ,
      • Duran C
      • Kumar N
      • Gometza B
      • et al.
      Indications and limitations of aortic valve reconstruction.
      In all rheumatic patients but even in many degenerative valves, scarring, retraction, and calcification of the Noduli Arantii can prevent central leaflet coaptation. Sometimes the Nodulus becomes a transverse linear bar of subtle calcium that will not conform to the midline and manifests a “double horn” sign. If Nodular retraction is encountered, the Noduli can be released by gently reducing Nodular thickness by approximately half, using an ultrasonic aspirator (Fig. 5). The tip of the ultrasonic device is applied to the sinus side of the Nodulus with a gentle back and forth “painting” motion to pulverize inflammatory calcium. Any residual fibrotic tissue then is excised sharply. While the long-term results of decalcifying heavily calcified valves with this technique were previously suboptimal,
      • Leithe ME
      • Harrison JK
      • Davidson CJ
      • et al.
      Surgical aortic valvuloplasty using the Cavitron ultrasonic aspirator: An invasive hemodynamic followup study.
      for strategically placed inflammatory Nodular or nontransmural leaflet calcification of less than 15% of the leaflet area, outcomes have been acceptable.
      • Mazzitelli D
      • Stamm C
      • Rankin JS
      • et al.
      Leaflet reconstructive techniques for aortic valve repair.
      Other leaflet reconstructive techniques are required occasionally, such as 7-0 polypropylene figure-of-eight sutures to close small leaflet holes, or in rare circumstances, pericardial patching for larger holes or ruptured commissures.
      • Mazzitelli D
      • Stamm C
      • Rankin JS
      • et al.
      Leaflet reconstructive techniques for aortic valve repair.
      In general, however, late outcomes with pericardial patching of any sort have been suboptimal because of pericardial tissue degeneration,
      • Karliova I
      • Schneider U
      • Tea E
      The fate of pericardial patches in tricuspid and bicuspid aortic cusp repair.
      and if a significant amount of pericardium needs to be added, prosthetic aortic valve replacement may be the most appropriate therapy.

      Valve Testing by Simultaneous Leaflet “Pressurization”

      At the conclusion of the AVr, the relative geometry of the 3 leaflets is tested by simultaneous gentle downward “pressurization” of all 3 leaflets with closed DeBakey forcep tips. For effective repair, the eH of all 3 leaflets should be equal to or greater than 8 mm, and the Noduli should meet in the midline (Fig. 6). A Schäfers eH caliper also can be useful.
      • Schafers H-J
      • Bierbach B
      • Aicher D.
      A new approach to the assessment of aortic cusp geometry.
      Because ring annuloplasty and leaflet-based sizing are effective in recruiting leaflets to the midline, proper vertical coaptation and good eH generally are readily achievable. An additional analysis technique involves placing a temporary Frater stitch,
      • Frater RWM.
      The prolapsing aortic cusp: Experimental and clinical observations.
      suturing the 3 Noduli together, and ensuring the length of each commissural leaflet segment is equal for all 3 commissures. If 1 leaflet is lower than the other 2, or has a longer commissural segment, additional perinodular plications are performed until central Nodular coaptation is optimal (Fig. 6). For proper coaptation, each leaflet should have a small amount of redundancy. Unlike mitral repair, where an operative water test accurately estimates leaflet competence, the exact geometry of reconstructed aortic valve leaflets can be fully ascertained only after aortic unclamping and root pressurization. In up to 10% of cases, particularly those with more complex leaflet reconstruction, reclamping may be required after review of the transesophageal echocardiogram to perform minor repair adjustments following the principles outlined above. However, the incidence of reclamping tends to fall with increasing surgeon experience.
      Figure 6
      Figure 6Valve testing by simultaneous leaflet “pressurization.”

      Bicuspid Valve Repair

      The principles of BAV repair are similar to TAV repair, but the goal is to create a 2-lealfet valve with cusps having equal eH's of >8 mm, equal FEL's, and close-to-equal gH's. Of prime importance is the annuloplasty ring, which establishes a smaller circular valve geometry with 180° commissures. The pathologic BAV is also elliptical, but with the long axis being the sinus-to-sinus diameter.
      • Mazzitelli D
      • Pfeiffer S
      • Rankin JS
      • et al.
      A regulated trial of bicuspid aortic valve repair supported by geometric ring annuloplasty.
      In fact, expansion of the sinus-to-sinus dimension may be pathophysiologically important in contributing to leaflet prolapse and AI. Bringing the valve to circular geometry and moving the sinus annuli centrally recruits leaflet to the midline for improved leaflet coaptation and eH. Again, an internal ring is the most effective method for BAV annuloplasty, reducing average annular diameter from 26.4 ± 2.3 mm to 21.6 ± 1.6 mm,
      • Mazzitelli D
      • Pfeiffer S
      • Rankin JS
      • et al.
      A regulated trial of bicuspid aortic valve repair supported by geometric ring annuloplasty.
      thus establishing a normal annular dimension and improved 180° commissural shape.
      • Capps SB
      • Elkins RC
      • Fronk DM.
      Body surface area as a predictor of aortic and pulmonary valve diameter.
      Also note that average pre- and postrepair annular diameters are similar for BAV and TAV disorders associated with AI.
      For repair of Sievers Type 1 BAV, the ring is sized by using the TAV ball sizer to determine the FEL of the nonfused BAV cusp (as shown in Fig. 3). The size then is confirmed by placing the ball within the valve to assess to the intercommissural distance. The ball should be only slightly smaller than the intercommissural distance, since the goal is to bring the sinuses centrally without reducing the intercommissural diameter by over a few millimeters.
      • Mazzitelli D
      • Pfeiffer S
      • Rankin JS
      • et al.
      A regulated trial of bicuspid aortic valve repair supported by geometric ring annuloplasty.
      The BAV ring most commonly is true-sized to the TAV ball that matches the FEL of the nonfused cusp. However, if the 180° stippled areas on the ball fit tightly into the intercommissural diameter, the BAV ring is downsized one size below that indicated on the tri-leaflet ball. Downsizing seems appropriate in around a fourth of valves, and this variability seems to be related to differences in general valve geometry, including relative sinus dimensions. Reoperative BAV cases with retracted leaflets also might prompt downsizing, but postoperative gradients can be more problematic with bicuspid rings, so downsizing is not as liberally applied as in TAV repairs.
      Usually, the fused raphe (Fig. 7A) is left alone because of the danger of reducing fused leaflet support and inducing late leaflet rupture. However, if calcium is present in the raphe, the fusion is opened and decalcified using the ultrasonic aspirator (Fig. 5). Any strategically placed calcium spicules in the annuli or leaflets also are removed, if total calcium is less than 15% of the leaflet area and nontransmural. When a fused commissure is opened for calcium removal, it subsequently is closed with a linear interrupted 5-0 polypropylene suture line, as part of the cleft closure (Fig. 7A and B). Thickened or dysplastic leaflet free edges are thinned using a combination of the ultrasonic aspirator applied to the sinus aspect of the leaflet, and shaving with a fine knife blade.
      Like the tri-leaflet ring, 4-0 polypropylene horizontal mattress sutures are placed to bury the 2 bicuspid ring posts into the 2 subcommissural triangles (Fig. 2), and the ring is lowered below the valve. Looping sutures then are positioned in the sinus annuli, 3 in the nonfused sinus and 4 in the fused sinus (2 on either side of the raphe). One less sinus suture can be used for 19 mm BAV rings, and conversely, if a sinus is especially large, more sutures should be placed to tightly oppose the ring to the entire length of the annulus. Again, the sutures should be placed 2 mm deep to the leaflet-aortic junction and tied tightly to prevent abrasive contact between the ring Dacron and leaflet tissue.
      After ring annuloplasty, the leaflet reconstruction is performed. Using Schäfers’ BAV leaflet repair,
      • Schaefers H-J.
      Reconstruction of the bicuspid aortic valve.
      the initial step is to raise the nonfused cusp to a reference eH of ≥8 mm, using perinodular plications of 6-0 polypropylene (Fig. 7B). With Sievers Type 1 BAV, the cleft in the fused leaflet reduces gH of that leaflet, and the cleft is closed with a linear suture line of 5-0 polypropylene to normalize gH. The cleft closure is continued toward the limit of the thickened cleft plaque, until the eH and FEL of the fused leaflet matches the nonfused cusp. The repaired valve is tested by stretching the commissures laterally, while the surgeon “pressurizes” both leaflets simultaneously with closed DeBakey tips (Fig. 7B). When the 2 leaflets match exactly and exhibit eH's of >8 mm, the repair is complete. Early in a surgeon's experience, a tendency exists toward overplication, with resultant higher valve gradients. If this occurs, the aorta can be reclamped, and a plication/cleft suture or 2 removed. Some learning curve is required for creating consistently excellent BAV leaflet geometry, with adequate eH and low gradients, but in a way, this is the beauty of BAV repair. In our current experience, less than 10% of BAV repairs exhibit any residual AI or a mean valve gradient of >15 mm Hg.
      Sievers Type 0 valves are similar to Type 1 defects, except the leaflet free edges are continuous without clefts. Because of cleft absence, gH of the 2 leaflets is similar, and only individual plications should be applied to both leaflets to correct prolapse. Shortening leaflet FEL with a linear suture line could increase gH too much, and cause “billowing” of the leaflet body below the annular plane. If Sievers Type 0 or 1 valves with mild to moderate AI are encountered during proximal aortic aneurysm surgery, AVr is considered if the annulus is dilated or if leaflet eH is <6 mm. Without correction, the aforementioned factors could predispose the patient to late AI, and AVr during the aneurysm procedure adds little to the operation. AVr for Type 0 BAV can be a simple procedure. However, some can exhibit severe preoperative AI because of very dilated annuli and major leaflet prolapse. AVr can be difficult, but employing geometric ring annuloplasty and associated techniques helps to simplify the repair.
      One can speculate about the cause of increasing gradients with overplication of BAV repairs. Plicating the leaflets to the point that the outflow circumference of the repaired BAV (i.e. leaflet FEL x 2) is smaller than the inflow circumference (the ring) probably induces flow acceleration through the valve and higher valve gradients. To prevent overplication (and therefore inordinate gradients), the FEL of each repaired leaflet is measured with a silk suture, and the leaflet is not plicated below a critical FEL of ½ of ring circumference. This maneuver, together with accurate sizing, has helped to mitigate previously observed higher gradients.
      • Rankin JS
      • Mazzitelli D
      • Fischlein TJM
      • et al.
      Bicuspid aortic valve repair using geometric ring annuloplasty: A first-in-humans pilot trial.
      However, if more plication is necessary because of specific leaflet anatomy or inadequate eH, initial mean gradients of 20-30 mm Hg may be acceptable, as these have been observed to normalize over time.
      • Rankin JS
      • Mazzitelli D
      • Fischlein TJM
      • et al.
      Geometric ring annuloplasty for aortic valve repair during aortic aneurysm surgery: Two-year clinical trial results.
      Another BAV category comprises Type 1 valves with only a small fusion at the top of the right-left commissure and a very large cleft - so called “intermediate-type” BAV. The valves often have 3 equal sinuses, and can be referred erroneously as TAV valves. The technical problem relates to variable amounts of deficient leaflet tissue in the right or left leaflets, or in the commissure. If the smallest leaflet sizes comfortably to a 19 mm tri-leaflet ball sizer, the valve usually can be repaired with a TAV ring. Most of the time, the ring is turned 120°, so the minor axis post is lying under the left-right commissure, in order to use ring ellipticality to bring the nonfused (usually noncoronary) cusp forward into better coaptation with the deficient commissure. With a tri-leaflet repair of intermediate-type BAV, one should be prepared for a more difficult plication procedure, because of frequent leaflet size disparities; however, fully competent valves are routine. On the contrary, if either the right or left cusp is smaller than 19 mm, then a standard 2-leaflet bicuspid repair is performed with a BAV ring. Whenever possible, though, a TAV ring reconstruction is preferred because of simplicity and better flow dynamics through TAV configurations.

      Unicuspid Valve Repair

      Unicuspid aortic valves (UAV) or Sievers Type 2 usually have a major fusion of the R-L commissure (with a cleft) and a minor fusion of the R-N commissure (without a cleft) (Fig. 8). This anatomy is present in over 90% of UAV cases.
      • Si M-S
      • Conte JV
      • Romano JC
      • et al.
      Unicuspid aortic valve repair using geometric ring annuloplasty.
      The valves often have 3 nearly equal sized sinuses, and patients frequently have systolic gradients because of more significant fusions. If the minor R-N fusion extends more toward the center of the valve, the patients tend to exhibit higher gradients, present with symptoms earlier in life, and require balloon valvuloplasty at a young age. In adult centers, UAV constitutes 5% of BAV defects, but in pediatric centers, UAV can comprise up to 50% of BAV cases.
      • Si M-S
      • Conte JV
      • Romano JC
      • et al.
      Unicuspid aortic valve repair using geometric ring annuloplasty.
      It is not uncommon for valves to have minor calcification in the fusions, requiring ultrasonic decalcification, as described above. More leaflet dysplasia also can be present, and the thickened leaflet margins can be thinned with gentle application of the ultrasonic aspirator to the sinus side of the dysplastic areas (Fig. 5) and shaving with a fine knife blade.
      The procedure is started by performing an aggressive commissurotomy of the minor R-N fused commissure (Fig. 8). Commissurotomy opens up the valve, and measurements of baseline annular diameter and nonfused (usually noncoronary) leaflet FEL are made after the commissurotomy. Any required commissural decalcification is performed, and if the major commissure is calcified (as described above), it is opened, decalcified with the ultrasonic device, and then closed with the cleft closure. The remainder of the UAV repair is similar to a Type 1 BAV reconstruction (Fig. 7).
      • Si M-S
      • Conte JV
      • Romano JC
      • et al.
      Unicuspid aortic valve repair using geometric ring annuloplasty.
      The ring is sized by measuring the FEL of the nonfused cusp, and the ring is true-sized or downsized depending on secondary measurements of intercommissural distance. After ring placement, the nonfused cusp is plicated to an eH of ≥8 mm and FEL approaching half of ring diameter. Then, the cleft is closed with a linear suture line until the FEL and eH of the 2 leaflets are similar. As described above, leaflet FEL is not shortened to less than half of the ring circumference unless unusual circumstances exist. Following this protocol, elimination of AI is achievable using native leaflet tissue only, and with a mean valve gradient less than 15 mm Hg in the majority of UAV patients.
      • Si M-S
      • Conte JV
      • Romano JC
      • et al.
      Unicuspid aortic valve repair using geometric ring annuloplasty.

      Aortic Sinus Remodeling

      With either TAV or BAV AVr, attention is given to proximal aortic replacement if the ascending aortic or transverse sinus diameter equals or exceeds 45 mm.
      • Svensson LG
      • Adams DH
      • Bonow RO
      • et al.
      Aortic valve and ascending aorta guidelines for management and quality measures.
      If the ascending aorta is aneurysmal but the sinus dimension is <45 mm, usually only the ascending aorta is replaced. Based on geometry studies,
      • Rankin JS
      • Bone MC
      • Fries PM
      • et al.
      A refined hemispheric model of normal human aortic valve and root geometry.
      ,
      • Crooke PS
      • Beavan LA
      • Griffin CD
      • et al.
      A geometric model of the normal human aortic root and design of a fully anatomic aortic root graft.
      a tube graft (and sino-tubular junction diameter) 7 mm larger than ring diameter is selected, although one graft size larger or smaller is acceptable to accommodate distal aortic size (Fig. 9).
      If the maximal sinus diameter equals or exceeds 45 mm, consideration is given to replacing any or all of the enlarged sinuses. The AVr is always performed first, then the segmental sinus circumference near the commissural tops is measured with the ball sizer that fit the leaflet FEL. If the segmental sinus circumference is over 10%-15% larger than the leaflet FEL, that sinus is replaced with a 120° tongue of a Valsalva graft, created by cutting the 120° lines on the graft doughnut vertically. Around one third of patients require replacement of only 1 sinus, another third, 2 sinuses, and in the rest, all 3 sinuses are replaced (including cases with severe aortopathy, such as Loeyz-Dietz syndrome). For bicuspid root aneurysms, 2 sinus tongues are created with a nonfused tongue of slightly less than 180°, and the other tongue correspondingly larger. The goal is to convert root geometry toward a 180°configuration, but because the native nonfused sinus usually is slightly smaller, making the tongues 180° can lead to suture line disparities. Again, it is recommended that the graft be 7 mm larger than the selected ring.
      Initially, the vertical incision in the Valsalva graft doughnut is carried up around 60% to the top of the expansile segment, and then during suturing, this incision is extended further to exactly accommodate commissural height. The corners of each tongue are rounded slightly, maximizing size of the graft sinuses. The remodeling suture line is started with a mattress suture from the center of the graft tongue to the sinus nadir, everting the graft to allow each subsequent suture to be taken with one bite. At the tops of the commissures, the sinus sutures are tied together, and the coronary buttons are reimplanted in the usual fashion. In addition to replacement of standard root aneurysms, and also sinus of Valsalva aneurysms, this method can be applied to dissections involving the root, again replacing any dissected sinuses with 1-3 remodeling tongues.
      • Jasinski MJ
      • Gocol R
      • Malinowski M
      • et al.
      Predictors of early and medium-term outcome of 200 consecutive aortic valve and root repairs.
      After completion of the aneurysm repair, leaflet coaptation should be re-evaluated as the final step.

      Summary

      AVr has steadily progressed since initial efforts by Cabrol,
      • Cabrol A
      • Guiraudon G
      • Bertrand M.
      Le traitement de l’insuffisance aortique par l’annuloplastie aortique.
      Carpentier,
      • Carpentier A.
      Cardiac valve surgery—the “French correction”.
      Cosgrove,
      • Cosgrove DM
      • Rosenkranz ERH
      • Hendren WG
      • et al.
      Valvuloplasty for aortic insufficiency.
      and Duran.
      • Duran C
      • Kumar N
      • Gometza B
      • et al.
      Indications and limitations of aortic valve reconstruction.
      The innovation of central leaflet plication by Schäfers and associates
      • Langer F
      • Graeter T
      • Nikoloudakis N
      • et al.
      Valve-preserving aortic replacement: Does the additional repair of leaflet prolapse adversely affect the results?.
      ,
      • Schaefers H-J
      • Aicher D
      • Langer F.
      Correction of leaflet prolapse in valve-preserving aortic replacement: Pushing the limits?.
      was a key advance, since leaflet prolapse is a prominent feature of AI. Annuloplasty also is important during AVr, and following Carpentier's concept, geometric annuloplasty rings were developed for placement into the inflow aspect of the aortic valve annulus.
      • Rankin JS
      • Mazzitelli D
      • Fischlein TJM
      • et al.
      Geometric ring annuloplasty for aortic valve repair during aortic aneurysm surgery: Two-year clinical trial results.
      ,
      • Rankin JS
      • Mazzitelli D
      • Fischlein TJM
      • et al.
      Bicuspid aortic valve repair using geometric ring annuloplasty: A first-in-humans pilot trial.
      After over 1000 clinical ring implants, techniques of AVr together with leaflet reconstruction have allowed successful repair of 40 different AI valve etiologies (Table 1) and over 90% of AI cases encountered. Longer-term follow-up of aortic ring annuloplasty now shows 8-year Kaplan-Meier survival and freedom from reoperation exceeding 80%.
      • Baker JN
      • Klokocovnik T
      • Miceli A
      • et al.
      Minimally invasive aortic valve repair using geometric ring annuloplasty.
      These results are consistent with other important late AVr follow-up studies,
      • Miyahara S
      • Schneider U
      • Marganthaler L
      • et al.
      Almost) all nonstenotic bicuspid aortic valves should be preserved or repaired.
      ,
      • Schneider U
      • Hofmann C
      • Schope J
      • et al.
      Long-term results of differentiated anatomic reconstruction of bicuspid aortic valves.
      although further experience and analysis will be required for full validation.
      Table 1Etiologies of AI Repaired With Geometric Ring Annuloplasty in over 1000 Clinical Cases
      A. Primary annular dilatation with leaflet defects (no aneurysm)
      1. Pure annular dilatation
      2. Isolated leaflet prolapse
      3. Ruptured leaflet fenestrations
      4. Extensive leaflet fenestrations
      5. Traumatic commissural/leaflet rupture
      6. Release of retracted leaflet Noduli
      7. Rheumatic aortic insufficiency
      8. Healed endocarditis
      B. Aneurysms
      9. Ascending aortic aneurysms with AI
      10. Tri-leaflet aortic root aneurysms with AI
      11. Syndromic aneurysms
      12. Aortic root dissections
      13. Complex arch aneurysms with AI
      14. Sinus of Valsalva aneurysm with AI
      15. Tri-leaflet and bicuspid root aneurysms with anomalous coronary arteries
      C. AI with concomitant procedures
      16. Multiple valve disease—degenerative, Marfan, rheumatic
      17. Coronary artery bypass with AI
      18. Destination VAD with AI
      D. Selected aortic stenosis
      19. Unicuspid valves with AS/AI and limited calcification
      20. Highly selected calcific aortic stenosis in bicuspid and tri-leaflet valves
      E. Revision of previous valve-sparing surgery
      21. Failed Yacoub procedure
      22. Failed David reimplantation
      23. Failed subcommissural annuloplasty
      24. Failed commissural resuspension for dissection
      F. Bicuspid aortic valve (BAV) defects
      25. Sievers Type 0 BAV insufficiency
      26. Sievers Type 1 BAV insufficiency
      27. Sievers Type 2 (unicuspid) BAV insufficiency
      28. BAV associated with ascending aortic and/or root aneurysms
      29. Variant BAV defects
      30. BAV repair after previous balloon valvuloplasty
      31. Repair of diminutive BAV
      G. Complex congenital defects
      32. VSD with AI
      33. LVOT membrane with AI
      34. Dilated ross autograft with AI
      35. TGA S/P arterial switch with AI/neoroot aneurysm
      36. Congenital aortic root aneurysm
      37. Truncus valves with AI
      38. Quadricuspid valves with AI
      39. Hypoplastic left heart syndrome, S/P Norwood procedure
      40. L-transposition S/P Fontan procedure with scarred-retracted aortic valve leaflet
      The concept of annuloplasty during AVr or valve sparing root operations has been widely described and recognized.
      • de Kerchove L
      • Mastrobuoni S
      • Boodhwani M
      • et al.
      The role of annular dimension and annuloplasty in tricuspid aortic valve repairdagger.
      • Lansac E
      • Di Centa I
      • Vojacek J
      • et al.
      Valve sparing root replacement: The remodeling technique with external ring annuloplasty.
      • Aicher D
      • Schneider U
      • Schmied W
      • et al.
      Early results with annular support in reconstruction of the bicuspid aortic valve.
      Several advantages of geometric ring annuloplasty over existing methods bare mentioning. Complete circumferential annuloplasty has proven advantageous over subcommissural suturing, which has been shown to be a long-term predictor of repair failure.
      • Jasinski MJ
      • Gocol R
      • Malinowski M
      • et al.
      Predictors of early and medium-term outcome of 200 consecutive aortic valve and root repairs.
      Valve reimplantation
      • David TE
      • Feindel CM
      • Webb GD
      • et al.
      Long-term results of aortic valve-sparing operations for aortic root aneurysm.
      reduces annular dimension with an external constricting Dacron graft; however, while effective, elliptical valve geometry is not restored and graft sizing is not based on objective criteria. The thickness of the aortic root wall can introduce variability in annular reduction relative to graft size. Deep external root dissection also is required. External annuloplasty can be performed with a Dacron band, similar to reimplantation.
      • Lansac E
      • Di Centa I
      • Bonnet N
      • et al.
      Aortic prosthetic ring annuloplasty: A useful adjunct to a standardized aortic valve-sparing procedure?.
      ,
      • Youssefi P
      • El-Hamamsy I
      • Lansac E.
      Rationale for aortic annuloplasty to standardize aortic valve repair.
      With this approach, a band usually is chosen to reduce the annulus by one size. As shown previously,
      • Jasinski MJ
      • Rankin JS
      • Mazzitelli D
      • et al.
      Leaflet dimensions as a guide to geometric annuloplasty during aortic valve repair.
      considerable variation exists in the degree of annular dilatation, so a one-size annular reduction seems less than precise. Annuloplasty also can be performed by circumferential suture annuloplasty either internally or externally located.
      • Aicher D
      • Schneider U
      • Schmied W
      • et al.
      Early results with annular support in reconstruction of the bicuspid aortic valve.
      With this approach, the Hegar-defined annular diameter usually is reduced to 23-25 mm, which again, may not be appropriate for all patients, and annuloplasty guided by leaflet size seems more objective.
      • Jasinski MJ
      • Rankin JS
      • Mazzitelli D
      • et al.
      Leaflet dimensions as a guide to geometric annuloplasty during aortic valve repair.
      Having the option of selecting either 2- or 3-leaflet reconstruction has significant utility for repairing more complex valve defects (Table 1), such as quadricuspid aortic valve.
      • McGuire JA
      • Hayanga HK
      • Hayanga JW
      • et al.
      Quadricuspid aortic valve repair facilitated by geometric ring annuloplasty.
      Finally, availability of internal ring annuloplasty possibly could allow expansion of AVr from 25% to 30% of AI cases with existing techniques
      • Alashi A
      • Khullar T
      • Mentias A
      • et al.
      Long-term outcomes after aortic valve surgery in patients with asymptomatic chronic aortic regurgitation and preserved LVEF: Impact of baseline and follow-up global longitudinal strain.
      ,
      • Yang L-T
      • Michelena HI
      • Scott CG
      • et al.
      Outcomes in chronic hemodynamically significant aortic regurgitation and limitations of current guidelines.
      to over 90%, as summarized in this report. Clearly, a learning curve exists with these relatively new procedures, requiring appropriate training and mentoring for safe and effective application. However, most clearly, longer-term clinical and echocardiographic follow-up for each specific subgroup of AI will be required to fully validate these approaches.

      Appendix. Supplementary materials

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