Atlas of Mitral Valve Repair, 1st Edition

6

Annuloplasty: Sutures, Bands, and Rings

ROLE AND APPLICATION OF ANNULOPLASTY

An annuloplasty is usually required to create proper leaflet apposition and prevent recurrent annular dilatation because annular dilatation is common to most cases of chronic mitral regurgitation (1). The aim is to remodel the annulus to a systolic shape. Cohn reported that the use of an annuloplasty ring was significantly associated with a reduced incidence of reoperation for repair failure (2). It is generally accepted that some sort of mechanical support is necessary to maintain the integrity of the repair, though some argue it can be used selectively (3,4). If some residual regurgitation is noted upon completion, the annuloplasty should prevent progression. Many different types of annuloplasty techniques have been described, some using plicating sutures, circumferential shortening sutures, bands to support the posterior annulus, and complete rings. Rings also have been rigid, semirigid, and completely flexible. Each technique has certain advantages and disadvantages. Rigid and semirigid rings enforce size reduction and shape change on the annulus, converting the native saddle-shaped annulus to a flat plane and restricting deformation through the cardiac cycle. Bands are designed to support the muscular annulus presuming that most of the change in annular size with regurgitation occurs there rather than in the fibrous anterior portion of the annulus. David examined a small group of patients (twenty-five) randomized to receive a rigid or flexible ring, and noted better systolic function in those with a flexible ring on short-term follow-up (5), though this was discounted by Carpentier as the differences disappeared on long-term follow-up (6). Unger-Graeber studied 122 patients who had repairs with a rigid or flexible ring or no ring and found that patients with rings have statistically significant, but clinically unimportant, reductions in valve area but no difference in diastolic velocity or gradient (7), while Detter et al. found similar results comparing a mural annulus shortening suture to a Carpentier-Edwards prosthetic ring (8). In contrast, Grossi et al. noted a survival benefit in patients with functional ischemic mitral regurgitation treated with ring annuloplasty in contrast to simple suture repair (9) and Czer et al. noted that ring annuloplasty was more effective in reducing and achieving a lower residual grade of regurgitation than commissural annuloplasty (10). Komoda et al. noted that a posterior pericardial annuloplasty tightly anchored to the trigones bilaterally eliminated breakdown after Gerbode plasty, in contrast to Paneth suture annuloplasty (11).

Good results have been reported with all annuloplasty techniques, perhaps the best approach is to choose a technique, learn it, and consistently apply it to maximize chances of consistent long-term success.

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SUTURE ANNULOPLASTY

Commissural Annuloplasty

Reed described a commissural annuloplasty called a “measured mitral annuloplasty” in 1965 (Fig. 6.1) (12). In 1980 he published 17-year results, describing 196 patients treated from 1961 to 1978, 35% of patients had been operated on for isolated mitral valve disease, 115 had annuloplasty and 81 had commissurotomy and annuloplasty. The age range was from 3 to 70 years. Reoperation was required in 8.7% of the patients (13).

Posterior Annuloplasty

Kay Annuloplasty

Kay et al. described a posterior suture annuloplasty using figure-of-eight sutures to reduce the posterior annulus circumference by one third (14) (Fig. 6.2).

Gerbode Annuloplasty

Gerbode described a posterior folding plasty similar to the Kay annuloplasty but in the center of the posterior leaflet (15) (Fig. 6.3).

Komoda et al. reviewed their experience with this technique noting the results with simple Gerbode plasty, Gerbode plasty with Paneth annuloplasty, and Gerbode plasty with loose reinforcement with a pericardial strip produced inadequate results. The cause of failure was the breakdown of the plication by the Gerbode plasty; however, Gerbode plasty combined with a tightly anchored pericardial strip from trigone to trigone produced excellent results (11) (Fig. 6.4). Note this technique creates a functional unileaflet valve.

Paneth Annuloplasty

Burr et al. described a circumferential mitral plication suture (Paneth-Burr method) (Fig. 6.5) which consisted of two sutures forming a U anchored in the central fibrous body on each side and running respectively around the left and right sides of the annulus, as a parallel double layer, to the midpoint of the posterior leaflet, and tied over a pledget (16). Though good results were reported in early follow-up, in 80 patients with good follow-up, they noted early failures in 13 patients, 7 for progression of rheumatic disease. They recommended not using the technique in elderly patients with rheumatic disease (17). In a sheep

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model, Tibayan et al. demonstrated that suture annuloplasty preserved annular and leaflet motion in contrast to the restriction of annular and leaflet motion by a ring (18).

 

Figure 6.1 Commissural annuloplasty. (From Reed GE. Repair of mitral regurgitation. An 11-year experience. Am J Cardiol. 1973:31:494-496.)

 

Figure 6.2 Kay posterior annuloplasty. (From Kay JH, Zubiate P, Mendez AM, Carpena C, Watanabe K, Magidson O. Mitral valve repair for patients with pure mitral insufficiency. 1-to 15-year follow-up. JAMA. 1976;236:1584-1586.)

 

Figure 6.3 Gerbode Posterior Plasty; schematic (A); surgical appearance (B); AML, anterior mitral leaflet; P, posterior mitral leaflet. (From Komoda T, Hubler M, Siniawski H, Hetzer R. Annular stabilization in mitral repair without a prosthetic ring. J Heart Valve Dis. 2000;9:776-782.)

 

Figure 6.4 Gerbode plasty reinforced with a posterior pericardial strip. The strip is sewn to the annulus with approximating sutures then secured with a running suture. (From Komoda T, Hubler M, Siniawski H, Hetzer R. Annular stabilization in mitral repair without a prosthetic ring. J Heart Valve Dis. 2000;9:776-782.)

Ricchi et al. describes a variation of this with one running suture line parallel to the annulus (Fig. 6.6) and the other placed perpendicular to the annulus in three segments around the posterior annulus to allow adjustment (Fig. 6.7) (19).

Barlow recently described using multiple annular sutures (Fig. 6.8) to create multiple plications of the annulus (20). This technique was used in 60 patients, over 124 months, with no failures after a mean follow-up of 29 months. They recommend use of an annuloplasty ring in the presence of gross annular degeneration or severe dilatation, if an optimal result has not been achieved without a ring, if the annulus requires extensive decalcification, or if the etiology is rheumatic or ischemic disease.

Suture Annuloplasty through the Ventricle

Menicanti et al. describe posterior suture annuloplasty through the left ventriculotomy as a component of the Dor procedure (21). As detailed in Fig. 6.9, the pledgeted 2-0 suture is

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brought from the ventricular to the atrial side at the right trigone, run along the annulus then brought back through to the ventricular side at the left trigone and tied over a pledget. A 23-millimeter valve sizer is used to calibrate the orifice size while tying.

 

Figure 6.5 Paneth-Burr posterior suture annuloplasty. (From Burr LH, Krayenbuhl C, Sutton MSJ, Paneth M. The mitral plication suture. A new technique of mitral valve repair. J Thorac Cardiovasc Surg. 1977;73:589-595.)

 

Figure 6.6 Linear segmental annuloplasty. The first segment of the posterior mitral annulus is encircled with 2/0 polypropylene suture. (From Ricchi A, Ortu P, Cirio EM, Falchi S, Lixi G, Martelli V. Linear segmental annuloplasty for mitral valve repair. Ann Thorac Surg. 1997;63:1805-1806.)

 

Figure 6.7 Linear segmental annuloplasty. The three 2/0 polypropylene sutures are passed in tourniquets. (From Ricchi A, Ortu P, Cirio EM, Falchi S, Lixi G, Martelli V. Linear segmental annuloplasty for mitral valve repair. Ann Thorac Surg. 1997;63:1805-1806.)

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Figure 6.8 Suture annuloplasty. (From Barlow CW, Ali ZA, Lim E, Barlow JB, Wells FC. Modified technique for mitral repair without ring annuloplasty. Ann Thorac Surg. 2003; 75:298-300.)

 

Figure 6.9 Posterior suture annuloplasty from the ventricular aspect. (From Menicanti L, Di Donato M, Frigiola A, et al. RESTORE Group: ischemic mitral regurgitation: intraventricular papillary muscle imbrication without mitral ring during left ventricular restoration. J Thorac Cardiovasc Surg. 2002; 123:1041-1050.)

RING OR BAND ANNULOPLASTY

Overview of Available Annular Support Prostheses

Though there are differences of opinion, most surgeons agree that durability of the repair is enhanced by some sort of structural support. As discussed in Chapter 2, on anatomy, the annular support of the valve is the fibrous and muscular portion and the transition point is the fibrous trigones. The annular support performs a dual role: shrinking the dilated annulus, returning the mitral orifice area toward normal allowing coaptation of the leaflets and preventing recurrent dilation leading to failure of the repair. Rings completely encircle the annulus and bands support the posterior annulus from trigone to trigone; they can be adjustable, rigid, semirigid or flexible. Flexible rings and bands are usually attached to a template to support them and prevent crimping (which can lead to foreshortening of the circumference) while tying. A circumferential ring may be preferable for a large ventricle secondary to cardiomyopathy or chronic ischemic disease in which annuloplasty is the principle component of the repair (22,23,24).

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Figure 6.10 Rigid and semirigid rings and bands.

Rigid and Semirigid Rings

Among the first manufactured prostheses was a rigid ring designed by Carpentier (Fig. 6.10A). This ring was designed to have an anterior-posterior to side-to-side ratio of 3:4. Made of titanium and covered with a polyester knit, this ring encircles and immobilizes the annulus. Similar in design is a semirigid ring, which is manufactured in a similar shape and proportion; the portion that attaches to the muscular annulus is somewhat flexible but its deformity is limited (Fig. 6.10B,6.10C). Sequin's semirigid ring is made with a flexible core that is high strength and fatigue resistant (Fig. 6.11) (25). Gradual reduction of the ring diameter increases flexibility around the posterior leaflet. This fixes the annulus and allows annular deformation. Resistance to longitudinal deformation prevents bunching while the ring is tied down. Semirigid bands are also available (Fig. 6.10D). New concepts for rigid and semirigid ring design are being explored; for example, an asymmetric ring for relatively greater reduction of the P3 segment for ischemia-induced regurgitation has recently been introduced.

Flexible Rings

Flexible rings and bands have no intrinsic shape and conform to the shape of the annulus tending to make it more circular instead of the D shape forced by a rigid ring (Fig. 6.12). Flexible prostheses will prevent radial expansion but not limit three-dimensional motion

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like a rigid or semirigid prosthesis does. The prosthesis is mounted on a tying template to prevent crimping during tying. The diameter of the mitral orifice can be adjusted during knot tying, depending on how much crimping is created. In addition, some flexible rings are designed to be adjustable, allowing the surgeon to shrink the circumference after tying the ring down, (Fig. 6.13), though Dr. A. Carpentier cautions against using an adjustable ring to compensate for an inadequate repair (personal communcation). Some flexible rings are designed to be used either as a ring or as a band, allowing a portion of the ring to be cut out as necessary (Fig. 6.12B).

 

Figure 6.11 Seguin semirigid ring. (see text) (From Seguin JR, Demaria R, Chaptal PA. Preservation of three-dimensional annular movement with the SJM, seguin mitral annuloplasty ring. J Heart Valve Dis. 1996;5:641-646.)

 

Figure 6.12 Complete and partial flexible rings and bands.

A number of authors report success using other available materials to support repair. Chang et al. used a 3-millimeter wide strip of polytetrafluoroethylene (PTFE) graft material

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tailored to the length of the free edge of the anterior leaflet and sewn to the posterior annulus between the commissures (26). Others have reported the use of saphenous vein (27), autologous pericardium (28), and Dacron. Scrofani et al. reported good long-term results with gluteraldehyde-treated pericardium sewn in place from commissure to commissure with mattress sutures to create an orifice of two finger breadths (29). Though this is in contrast to results presented by Bevilacqua et al. who noted a five-year freedom from reoperation rate of 90.1% for the Carpentier-Edwards ring and 62.6% for a posterior pericardial band (30); most frequently from suture dehiscence of posterior annulus plication and leaflet reconstruction with partial ring detachment.

 

Figure 6.13 Adjustable flexible ring. (From Gorton ME, Piehler JM, Killen DA, Hoskins ML, Borkon AM. Mitral valve repair using a flexible and adjustable annuloplasty ring. Ann Thorac Surg. 1993;55:860-863.)

Which Band Should Be Used and When?

Though there are many different brands with minor differences between them, they all are either bands or rings, rigid or flexible, with a fixed or adjustable circumference. Usage depends on the surgeon; for most situations, any prosthesis will perform the primary role of support. However, some recommendations for use of specific prostheses in selected situations can be made. In general, a band will provide good support when the leaflet repair itself reduces annular circumference. A band is also useful if the anterior portion of the annulus is difficult to visualize. A complete ring may provide more support in a situation in which the surgeon relies on the ring to reduce annular circumference, for example a simple annuloplasty for ischemic disease or dilated cardiomyopathy. Rigid rings have been more prone to the creation of systolic anterior motion, however, techniques that restrict the height of the posterior leaflet prevent this. Okada et al. compared Carpentier and Duran rings noting greater left ventricular fractional shortening and lower peak velocity with the flexible Duran ring (31); the clinical significance of this is unclear. Most prostheses are not adjustable, however, Gorton et al. reported adjustment after attachment to reduce or eliminate residual regurgitation was beneficial in 9 of 21 patients (32). Borghetti et al. examined the relative effects of a rigid (Carpentier-Edwards) vs. flexible (autologous pericardium) annuloplasty ring (33). They noted only one major difference—improvement in the ejection fraction with exercise with the flexible ring, which they attributed to improved mitral annular systolic excursion. In contrast, Bevilacqua et al. noted inferior long-term results with glutaralehyde-treated autologous pericardial posterior annuloplasty in comparison to the standard Carpentier ring (34). Gillinov reported midterm results with the Cosgrove-Edwards annuloplasty band, describing at a mean follow-up interval of 18 months no MR or 1+ MR in 80% of patients (35), and stated that results with a posterior annuloplasty were equivalent to circumferential annuloplasty (36).

INSERTION TECHNIQUE

In general proper ring (band) insertion will require 13-25 (9,10,11,12,13,14,15,16,17,18,19,20) sutures depending on the degree of annular dilation. Sutures can be placed parallel or radial to the annulus. If parallel to the annulus, sutures should be placed at a depth of between 2 and 3 millimeters with a width of between 4 and 5 millimeters. For a very large annulus, consideration should be given to placing many narrowly placed sutures or overlapping sutures for additional security. Care must be taken to insert the sutures in the annular/atrial tissue and not the leaflet tissue; it is important not to impede the hinge function of the leaflet (A. Carpentier, personal communication). When placed through the ring, sutures from the fibrous portion of the annulus should be placed at a width similar to that of the annular suture because no annular reduction is anticipated for the fibrous portion. In contrast the width of the sutures for the posterior annulus is much smaller on the ring, facilitating size reduction. The approach is similar for radial sutures taking care to avoid gaps between the ring and the annulus. Care should be taken not to alter the circumference of the ring while tying. Rigid and semirigid rings will not deform. However, when tied, horizontal sutures will bunch up flexible rings. Tying sutures while the ring or band is attached to the template it is mounted on will prevent this. Often flexible rings and bands are mounted on a template that is not of the classic 3:4 proportion,

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but wider in the lateral dimension and narrower in the anterior-posterior dimension, requiring that the ring or band be cut off the template sequentially as it is sewn down; after a portion of sutures are tied while attached to the template to prevent crimping, the suture holding the prosthesis on the template is cut and the prosthesis avulsed off the template. Begin at the left trigone, tying 3 or 4 sutures, then cut the retention suture on the anterior annulus and avulse the left trigone area, proceeding around the right trigone and alternating on each side to the middle of the posterior annulus in a similar fashion. This allows the ring or band to be secured in place without crimping the prosthesis (Figs. 6.14,6.15,6.16,6.17).

 

Figure 6.14 Placement of annuloplasty sutures. (Clip 4, Case 4) 

 

Figure 6.15 Placement of annuloplasty sutures. (Clip 8, Case 1) 

SIZING

Ring sizing and placement may vary among manufacturers. As a general rule, the mitral annulus should have a surface area similar to that of the anterior leaflet. With a ring sized to a 3:4 ratio, the intertrigonal distance will be proportional to the anterior leaflet size and used to select a ring (A. Carpentier uses the intercommissural distance, personal communication). The central anterior-posterior diameter (height) of the anterior leaflet should equal that of the ring. Ideal sizing should reduce annular size to produce a surface of coaptive contact of at least 0.5 mm between the anterior and posterior leaflets. In situations of annular reduction for cardiomyopathy and ischemic disease some surgeons advocate placing the smallest ring possible. Though it is theoretically possible to create mitral stenosis, significant stenosis is unusual with simple annular reduction (Figs. 6.18,6.19,6.20,6.21,6.22).

 

Figure 6.16 Placement of sutures through the annuloplasty band. (Clip 10, Case 1) 

 

Figure 6.17 Securing the ring. (Clip 8, Case 6) 

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Figure 6.18 Sizing the annuloplasty ring. (Clip 4, Case 2) 

 

Figure 6.19 Sizing the annuloplasty band. (Clip 5, Case 3) 

 

Figure 6.20 Sizing the annuloplasty band. (Clip 5, Case 4) 

 

Figure 6.21 Sizing the annuloplasty ring. (Clip 7, Case 6) 

 

Figure 6.22 Sizing the annuloplasty band. (Clip 9, Case 1) 

 

Figure 6.23 Asymmetric annuloplasty. (From Chitwood Jr. WR. Mitral valve repair: ischemic. In: Kaiser LR, Kron IL, Spray TL. Mastery of Cardiothoracic Surgery. Philadelphia: Lippincott-Raven, 1998:317.)

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Asymmetric Annuloplasty

Various techniques exist to deal with the asymmetry of ischemic mitral regurgitation. One of these techniques is asymmetric placement of the annuloplasty ring to compensate for the asymmetry of the posterior leaflet abnormality (37). This technique is demonstrated in (Fig. 6.23). Note a greater reduction in the annular circumference between points b and d relative to that between b and c. As stated above newer rings have been designed to replicate this approach.

REFERENCES

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  20. Barlow CW, Ali ZA, Lim E, Barlow JB, Wells FC. Modified technique for mitral repair without ring annuloplasty. Ann Thorac Surg.2003;75:298-300.
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