Mitral valve annuloplasty rings: review of literature and comparison of functional outcome and ventricular dimensions.

REVIEW ARTICLE

Mitral Valve Annuloplasty Rings Review of Literature and Comparison of Functional Outcome and Ventricular Dimensions Arash Khamooshian, MD,* Marc P. Buijsrogge, MD, PhD,Þ Frederiek de Heer, PhD,Þ and Paul F. Gru¨ndeman, MD, PhDÞ Abstract: In the past decades, more than 40 mitral valve annuloplasty rings of various shapes and consistency were marketed for mitral regurgitation (MR), although the effect of ring type on clinical outcome remains unclear. Our objective was to review the literature and apply a simplification method to make rings of different shapes and rigidity more comparable. We studied relevant literature from MEDLINE and EMBASE databases related to clinical studies as well as animal and finite element models. Annuloplasty rings were clustered into 3 groups as follows: rigid (R), flexible (F), and semirigid (S). Only clinical articles regarding degenerative (DEG) or ischemic/dilated cardiomyopathy (ICM) MR were included and stratified into these groups. A total of 37 rings were clustered into R, F, and S subgroups. Clinical studies with a mean follow-up of less than 1 year and a reported mean etiology of valve incompetence of less than 60% were excluded from the analysis. Fortyone publications were included. Preimplant and postimplant end points were New York Heart Association class, left ventricular ejection fraction (LVEF), left ventricular end-systolic dimension (LVESD), and left ventricular end-diastolic dimension (LVEDD). Statistical analysis included paired-samples t test and analysis of variance with post hoc Bonferroni correction. P G 0.05 indicated statistical difference. Mean T SD follow-up was 38.6 T 27 and 29.7 T 13.2 months for DEG and ICM, respectively. In DEG, LVEF remained unchanged, and LVESD decreased in all subgroups. In our analysis, LVEDD decreased only in Fand R, and S did not change; however, the 4 individual studies showed a significant decline. In ICM, New York Heart Association class improved in all subgroups, and LVEF increased. Moreover, LVESD and LVEDD decreased only in F and S; R was underpowered (1 study). No statistical difference among R, F, and S in either ICM or DEG could be detected for all end points. Overall, owing to underpowered data sets derived from limited available publications, major statistical differences in clinical outcome between ring types could not be substantiated. Essential end points such as recurrent MR and survival were incomparable. In conclusion, ring morphology and consistency do not seem to play a major clinical role in mitral valve repair based on the present literature. Hence, until demonstrated otherwise, surgeons may choose their ring upon their judgment, tailored to specific patient needs. Accepted for publication October 13, 2014. From the *University Medical Center Groningen; and the †University Medical Center Utrecht, Utrecht, the Netherlands. Disclosure: The authors declare no conflicts of interest. Address correspondence and reprint requests to Paul F. Gru¨ndeman, MD, PhD, Division of Heart and Lungs, University Medical Center Utrecht, Heidelberglaan 100, Room G.02.523, Utrecht, the Netherlands. E-mail: [email protected]. Copyright * 2014 by the International Society for Minimally Invasive Cardiothoracic Surgery ISSN: 1556-9845/14/0906-0399

Innovations & Volume 9, Number 6, November/December 2014

Key Words: Mitral valve, Annuloplasty rings, Mitral valve regurgitation, Mitral valve repair, Valvuloplasty. (Innovations 2014;9:399Y415)

M

itral regurgitation (MR) is the most common heart valve disease in the United States1 and the second in Europe.2 Degenerative MR is the main etiology in the western world, thereby representing a major health problem.1Y3 The preferred therapy has proven to be mitral valve (MV) repair rather than replacement as of some major advantages include a low rate of thromboembolic events, superior survival, and resistance to endocarditis.4Y12 The ultimate goal of valve repair is to create a sufficient valve by preservation or restoration of leaflet mobility, stabilization of the annulus, and creation of an adequate cooptation area of the anterior and posterior MV leaflet.13 In this review, the focus is on the second goal of MV repair, that is, stabilization of the annulus by annuloplasty rings. In the past decades, many annuloplasty rings have become commercially available after Alain Carpentier introduced the completely rigid Carpentier Classic ring in 1971.14 Since then, annuloplasty rings have been evolving in shape, materials, and adjustability. A relatively new development in the field are postsurgically adjustable rings and etiology-specific rings, which have very distinct shapes.15Y18 The MV is a unique and complex unit, which has been investigated intensively. There is extensive knowledge about its morphology, 3-dimensional configuration, and annular consistency. Annular dilatation plays an important role in the development of MR, and although valve repair itself remains the most significant component of the operation, the final step of applying an annuloplasty ring is crucial for a successful repair. As a result, annuloplasty rings have been the center of debate for a long time. Although it would be likely, a certain consensus on ring selection has not yet been reached. The diversity in commercially available rings and their features in particular make this rather a difficult process. The clinical and surgical outcome overall of MV repair is satisfying in degenerative disease, but still, many questions remain unanswered concerning the effect of different ring types on clinical outcome; in particular, ring form and rigidity are interesting. Ideally, we would want to work toward a patient-specific ring selection regarding MR etiology and Carpentier Triade classification. However, because the amount of annuloplasty rings relatively outnumbers the available literature concerning each specific ring, no conclusion can be drawn by interpreting studies separately. Therefore, a simplification procedure needs to be applied to compare major ring features. The aim of this article was to make the large amount of commercially available MV annuloplasty

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Khamooshian et al

rings comparable by organizing them in 3 major groups based on their rigidity (Table 1). The focus will solely be on MR caused by degenerative disease (DEG) and ischemic/idiopathic dilated cardiomyopathy (ICM). Furthermore, we will outline the majority of the experimental and corresponding clinical studies.

rigid (R), flexible (F), and semirigid (S) groups according to their consistency and shape. Literature searches were performed using relevant key words and individual ring names in MEDLINE. The related articles section in MEDLINE and bibliographies of the selected articles were reviewed manually.

METHODS

All articles reporting a clinical or echocardiographic outcome of MV repair in patients with MR caused by DEG or ICM with a minimal follow-up period of 1 year were included. Studies with a mixed MR etiology were excluded from our analysis when less than 60% of the study population had degenerative MR. Studies not mentioning data of individual ring types were also excluded.

Search Strategy Initially, a general Internet search was performed; information and photo material from manufacturers’ Web sites on commercially available mitral annuloplasty rings were gathered. Thirty-seven different rings were identified and stratified into

Study Inclusion

TABLE 1. Commercially Available Mitral Valve Annuloplasty Rings Ring Group Rigid

Shape

Manufacturer

Name

D-shaped planar

Edwards Lifesciences Sorin Group Maquet Getinge AB Edwards Lifesciences Edwards Lifesciences Medtronic Edwards Lifesciences St. Jude Medical Medtronic St. Jude Medical Sorin Group Sorin Group ATS Medical Maquet Getinge AB St. Jude Medical ATS Medical Maquet Getinge AB Edwards Lifesciences Medtronic St. Jude Medical Sorin Group Sorin Group Sorin Group ATS Medical Medtronic Peter’s Surgical Kalangos Shelhigh V V Edwards Lifesciences Edwards Lifesciences St. Jude Medical Medtronic Sorin Group ATS Medical Genesee Biomedical Medtronic Maquet Getinge AB

Carpentier-Edwards Classic* Carbomedics Annuloflo Rigid Ring† Carpentier-McCarthy-Adams IMR ETlogix* GeoForm* Profile 3D* Myxo ETlogix* Rigid Saddle Ring with EZ Suture Cuff Duran AnCore* Tailor Flexible Ring Carbomedics Annuloflex* Carbomedics Sovering* Simulus Flexible Annuloplasty Ring La Pitie´ Ring† Attune Adjustable Ring Simulus Adjustable Ring Adjustable Ring† Cosgrove Edwards flexible band* Duran AnCore flexible band Tailor Flexible band* Carbomedics Annuloflex band Carbomedics Sovering Miniband Carbomedics Sovering band Simulus Flexible Annuloplasty band Simplici-T annuloplasty system Uniring Biodegradable Bioring* BioRing Pericardium annuloplasty* Suture annuloplasty Carpentier-Edwards Physio I* Carpentier-Edwards Physio II* Se´guin* Colvin Galloway Future Ring* Carbomedics Memo 3D Simulus Semi-Rigid Ring Sculptor Ring*† Colvin Galloway Future band* Maazouzi†

Saddle shaped

Flexible

D-shaped

C-shaped

Bands

Semirigid

Saddle-shaped

D-shaped planar

C-shaped *Available literature. †Ring is not available anymore.

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Copyright * 2014 by the International Society for Minimally Invasive Cardiothoracic Surgery



Studies were stratified into 2 groups as follows: DEG and ICM. Both strata were then subdivided in 3 subgroups as follows: studies with R, F, and S annuloplasty rings. A total of 217 articles were selected in the first review (Fig. 1). Fifty-four were clinical observational studies or (randomized) trials (DEG, 32; ICM, 23). A total of 41 articles were included (DEG, 2319Y41; ICM, 1816,34,42Y57). Individual ring type data from studies comparing 2 or more annuloplasty rings were analyzed separately in this study, referred to as inputs. The total amount of inputs was 54 (DEG, 30; ICM, 24).

End Points The following data were processed in a database: ring type, study size, mean age, mean follow-up in months, percentage of degenerative disease, percentage of concomitant coronary artery bypass grafting (CABG), survival, freedom from reoperation, preoperative MR, postoperative MR, preoperative New York Heart Association (NYHA) class, postoperative NYHA class, preoperative left ventricular ejection fraction (LVEF), postoperative LVEF, preoperative left ventricular end-diastolic dimension (LVEDD), postoperative LVEDD, preoperative left ventricular end-systolic dimension (LVESD), postoperative LVESD.

Statistical Analysis Preoperative and postoperative data were analyzed using the Student 2-sided paired-samples t test. Differences among the R, F, and S subgroups were analyzed with the 1-way analysis of variance with post hoc Bonferroni correction. A

Annuloplasty Rings in Mitral Valve Repair

P G 0.05 indicated statistical difference. All the values are depicted as mean T SD.

RESULTS A total of 23 studies were reviewed in the DEG group and 18 in the ICM group. These studies included 3869 (mean T SD, 129 T 111.5) and 1911 (mean T SD, 79.6 T 74.9) patients who underwent MV repair, in the DEG and ICM groups, respectively. Mean T SD age in years and follow-up in months were 59.2 T 5.8 and 40.5 T 29.0 in the DEG group and 65.7 T 3.9 and 29.7 T 13.2 the ICM group, respectively. One study34 in the DEG group and 2 studies34,49 in the ICM group did not mention mean age. In the DEG group, 81.9% T 14.7% of the patients had degenerative MR. In the ICM group, 19 inputs had more than 95% concomitant CABG, with a total mean T SD of 87.3% T 28.4% CABG. Twenty-two inputs included patients with ischemic cardiomyopathy, and 2 inputs included patients with dilated cardiomyopathy. Two randomized trials25,41 were included (both in the DEG group). The remaining 39 studies were retrospective or prospective observational studies, of which 10 (520,21,26,33,35 in the DEG, 449,52,54,55 in the ICM, and 134 in both groups) compared 2 or more ring types. All mean values of the end points are reported in Table 2. Table 3 depicts the basic characteristics of all subgroups; for detailed study outcomes see Tables 4 through 7 and Figures 2 and 3.

Left Ventricular Ejection Fraction In the DEG group, 10 studies20,22,23,25,26,29,32,34,37,38 (13 inputs) reported a preoperative and postoperative LVEF

FIGURE 1. Study selection flow chart. Of 217 articles, 23 in the degenerative group and 18 in the ischemic/dilated cardiomyopathy group were selected. These resulted in 30 and 24 inputs. Copyright * 2014 by the International Society for Minimally Invasive Cardiothoracic Surgery

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Khamooshian et al

(Table 5). No difference was found in study size, fraction of degenerative disease, and mean age. Mean follow-up was shorter in the S group. Left ventricular ejection fraction remained unchanged after annuloplasty, and no difference was found among the R, F, and S subgroups. In the ICM group, 13 studies16,34,43Y48,50Y52,55,57 (16 inputs) reported a preoperative and postoperative LVEF (Table 7). No difference was found between the groups in study size, concomitant CABG, mean age, and follow-up. The R group did not show a significant change in postoperative LVEF. The LVEF increased in the F and S group. No differences were found among the R, F, and S subgroups.

Left Ventricular End Diastolic Diameter DEG group: 520,22,25,29,39 studies (7 inputs) reported a preoperative and postoperative LVEDD (Table 5). No difference in study size, fraction of degenerative disease and mean age could be found. Mean follow-up was shorter in the S group. All subgroups showed a decline in diastolic diameter, however only the decline in the F group reached statistical significance. No difference between the R, F and S subgroups could be detected. ICM group: 1042Y44,46,47,51,52,54,55,57 studies (14 inputs) reported a preoperative and postoperative LVEDD (Table 7). No difference in study size, fraction of concomitant CABG, mean age and follow-up was found. The R group contained 1 input (3.7 mm decline), the F and S groups showed a significant decline in postoperative LVEDD. No difference between the R, F and S subgroups could be detected.

Left Ventricular End-Systolic Diameter In the DEG group, 6 studies20,22,25,26,29,39 (9 inputs) reported a preoperative and postoperative LVESD (Table 5). No difference between study size, fraction degenerative disease, and mean age was found. Mean follow-up was shorter in the S group. The LVESD decreased in all the subgroups, with no difference between the groups. In the ICM group, 10 studies42Y44,46,47,51,52,54,55,57 (14 inputs) reported a preoperative and postoperative LVESD (Table 7). No difference between the groups was found in study size, fraction of concomitant CABG, mean age, and follow-up. The R group included 1 study (4.1-mm decline). The F and S groups showed a significant decline in systolic diameter after annuloplasty. No difference between the subgroups could be detected.

NYHA Class The DEG group did not contain a sufficient amount of data to be analyzed (Table 4). In the ICM group, 13 studies42Y44,46Y48,50Y55,57 (17 inputs) reported a mean preoperative and postoperative NYHA class (Table 6). No difference was found between the groups in study size, fraction of concomitant CABG, mean age, and follow-up. Mean NYHA class declined in all subgroups postoperatively. No difference between the subgroups could be detected.

DISCUSSION During the past 30 years, a wide range of MV annuloplasty rings have entered the market. Most of the variation in

402

design is focused on consistency (rigidity) and shape (flat, saddle shaped, open, closed). Manufactures all claim having conceptually the most suited prosthetic for MR repair. These claims are mainly based on experimental and noncomparative (follow-up) studies, of which some unfortunately demonstrate discrepancies between the results. With this in mind, it is very challenging to make a firm conclusion regarding the effect of ring type on cardiac physiology, annulus geometry, and the MV nonplanarity. Aside from the direct anatomic effect of annuloplasty on the MV, a more relevant question would be whether ring type influences the clinical outcome after cardiac remodeling has occurred (at least 12 months postoperatively). Although most of the clinical studies provide well midterm to long-term results, no systematic comparison has been made yet among the different annuloplasty ring types. When we initiated this study, our goal was to make an assessment of the different rings on the market. The main difficulty we encountered was the differences in study end points or the incomparability of the results. End points such as recurrent MR, NYHA class, reoperation-free survival, MR-free survival, and overall survival are crucial for a systematic comparison. We found it striking that the majority of the studies did not mention postoperative MR. The various survival parameters were not systematically comparable either because follow-up periods could not be matched. No important survival differences between the ring groups could be detected by displaying survival data graphically (not shown in this article). All ring groups had good-to-excellent survival (Tables 5 and 7). Because our end points of choice could not be used for a systematic analysis, we were forced to use other available, acceptable alternatives such as LVEF and cardiac dimensions (LVEDD and LVESD). Our present data show that a postoperative LVEF change in the DEG group is likely to be dependent on the preoperative LVEF. Although the R, F, and S groups did not have the same preoperative LVEF (however, no significant difference between the groups in our analysis), postoperative LVEF became more comparable, with no differences between the ring groups. These data are difficult to compare because of the preoperative differences in LVEF; nonetheless, no major influence of ring type on the outcomes could be detected. In the ICM group, the study population had a much lower preoperative LVEF, which improved significantly after MV repair. This indicates the ability of ischemic affected hearts to partially restore after CABG and MV repair. The R group was underpowered (2 inputs) but showed the same trend. It is safe to say that ring type has no major influence on LVEF in both DEG and ICM groups based on present available data. The postoperative LVESD decreased in both DEG and ICM groups. The R subgroup in the ICM group was underpowered with the availability of just 1 study, although it showed the same decline in systolic diameter. Noticeable is the larger preoperative LVESD of the ICM group, which shows less postoperative decline than that of the DEG group. This could indicate the inferior remodeling capacity of an ischemic heart. The same is the case for the diastolic diameters. Although in our analysis, the R and S subgroups in the DEG group did not decline significantly, the same trend was seen. We believe that this was caused by the low power. In both the DEG and ICM groups, we found no difference among the R, F, and S subgroups in the analysis of variance.



NA NA 61.6 T 5.8 (n = 4) 57.1 T 2.3 (n = 4) 43.9 T 4.6 (n = 3) 35.0 T 1.9 n = 3)* 59.1 T 1.1 (n = 2) 50.4 T 2.3 (n = 2)

Rigid

57.2 T 56.1 T 42.8 T 35.6 T 62.1 T 52.1 T

NA NA 7.9 (n = 4) 6.4 (n = 4) 2.9 (n = 4) 2.2 (n = 4)* 3.8 (n = 3) 1.6 (n = 3)*

Flexible

DEG Group NA NA 53.4 T 8.2 (n 55.2 T 4.4 (n 41.1 T 2.0 (n 33.6 T 2.0 (n 61.9 T 3.7 (n 50.5 T 0.1 (n = 5) = 5) = 2) = 2)* = 2) = 2)

Semirigid 3.2 T 0.1 (n 1.1 T 0.0 (n 39.4 T 0.5 (n 42.9 T 4.0 (n 52.4 (n 48.3 (n 65.1 (n 61.4 (n

Rigid = 2) = 2)* = 2) = 2) = 1) = 1) = 1) = 1)

3.0 T 0.3 (n = 6) 1.6 T 0.5 (n = 6)* 34.1 T 8.3% (n = 7) 40.5 T 7.1% (n = 7)* 45.6 T 5.6 (n = 5) 41.5 T 5.1 (n = 5)* 58.8 T 5.4 (n = 5) 55.6 T 4.6 (n = 5)*

Flexible

ICM Group 3.0 T 0.5 1.4 T 0.4 36.8 T 5.8 44.8 T 3.3 48.6 T 4.2 42.7 T 4.8 61.8 T 3.4 56.9 T 4.1

(n = 9) (n = 9)* (n = 6) (n = 6)* (n = 8) (n = 8)* (n = 8) (n = 8)*

Semirigid


55.9 (n = 3) 17.7 (n = 3) 6.3 (n = 3) 5.6 (n = 3)*

77.1 (n = 2) 21.6 (n = 2) 8.7 (n = 2) 7.8 (n = 2)*

138.7 T 89.8 T 54.7 T 41.6 T

131.5 T 84.7 T 55.6 T 41.1 T

NA NA NA NA

47.5 (n = 4) 14.4 (n = 4) 5.2 (n = 4) 10.6 (n = 4)*

132.0 T 89.9 T 54.3 T 46.4 T

NA NA NA NA

113.0 T 57.0 (n = 3) 87.6 T 21.4 (n = 3) 57.6 T 7.1 (n = 3) 38.2 T 7.5 (n = 3)*

120.0 T 48.6 (n = 4) 90.7 T 18.6 (n = 4) 56.5 T 6.2 (n = 4) 35.8 T 7.8 (n = 4)*

110.0 T 54.3 (n = 4) 90.7 T 18.6 (n = 4) 55.9 T 7.5 (n = 3) 38.8 T 8.4 (n = 4)*

Flexible

DEG Group

NA NA NA NA

51.5 T 16.3 (n = 2) 66.0 T 5.7(n = 2) 69.3 T 1.4(n = 2) 13.9 T 3.7(n = 2)*

51.5 T 16.3 (n = 2) 66.0 T 5.7 (n = 2) 69.3 T 1.3 (n = 2) 13.9 T 3.7 (n = 2)*

173.4 T 159.0 (n = 5) 69.4 T 8.9 (n = 5) 61.7 T 8.7 (n = 5) 17.6 T 6.4 (n = 5)*

Semirigid LVEF Study size CABG, % Mean age Follow-up LVESD Study size CABG, % Mean age Follow-up LVEDD Study size CABG, % Mean age Follow-up NYHA class Study size CABG, % Mean age Follow-up

76.0 T 100 T 63.7 T 18.7 T

= 1) = 1) = 1) = 1) 72.1 (n = 2) 0.0 (n = 2) 8.2 (n = 2) 1.3 (n = 2)

25.0 (n 69.5 (n 100.0 (n 17.8 (n

= 1) = 1) = 1) = 1)

10.6 (n = 2) 22.6 (n = 2) 1.1 (n = 2) 6.9 (n = 2) 25.0 (n 69.5 (n 100.0 (n 17.8 (n

32.5 T 84.0 T 68.8 T 22.7 T

Rigid

63.2 T 34.3 (n = 6) 82.7 T 36.0 (n = 6) 65.1 T 3.5 (n = 6) 28.9 T 17.0 (n = 6)

63.6 T 38.3 (n = 5) 79.2 T 39.2 (n = 5) 64.3 T 3.2 (n = 5) 26.8 T 18.1 (n = 5)

63.6 T 38.3 (n = 5) 79.2 T 39.2 (n = 5) 64.3 T 3.2 (n = 5) 26.8 T 18.1 (n = 5)

57.1 T 22.2 (n = 7) 77.3 T 35.8 (n = 6) 65.9 T 3.9 (n = 7) 31.7 T 17.4 (n = 7)

Flexible

ICM Group

57.4 T 31.0 (n = 9) 88.9 T 33.4 (n = 9) 65.6 T 4.0 (n = 9) 27.7 T 11.2 (n = 9)

52.1 T 28.4 (n = 8) 87.5 T 35.4 (n = 8) 65.2 T 4.1 (n = 8) 27.4 T 11.9 (n = 8)

52.1 T 28.4 (n = 8) 87.5 T 35.4 (n = 8) 65.2 T 4.1 (n = 8) 27.4 T 11.9 (n = 8)

59.1 T 35.5 (n = 7) 85.7 T 37.8 (n = 7) 66.0 T 4.6 (n = 7) 30.2 T 11.2 (n = 7)

Semirigid

Values are presented as mean T SD. n indicates the number of relevant inputs. *P G 0.05 (between subgroups). CBAG indicates coronary artery bypass grafting; DEG, degenerative group; ICM, ischemic/dilated cardiomyopathy group; LVEDD, left ventricular end-diastolic diameter; LVEF, left ventricular ejection fraction; LVESD, left ventricular end-systolic diameter; NA, not available; NYHA, New York Heart Association classification.

Study size Degenerative, % Mean age Follow-up LVESD Study size Degenerative, % Mean age Follow-up LVEDD Study size Degenerative, % Mean age Follow-up NYHA class Study size Degenerative, % Mean age Follow-up

LVEF

Rigid

TABLE 3. Basic Characteristics

Values are presented as mean T SD. No significant difference between the subgroups was found. n indicates the number of relevant inputs. *P G 0.05 (vs preoperative value). DEG indicates degenerative group; ICM, ischemic/dilated cardiomyopathy group; LVEDD, left ventricular end diastolic diameter; LVEF, left ventricular ejection fraction; LVESD, left ventricular end-systolic diameter; NA, not available; NYHA, New York Heart Association classification.

Preoperative NYHA class Postoperative NYHA class Preoperative LVEF Postoperative LVEF Preoperative LVESD Postoperative LVESD Preoperative LVEDD Postoperative LVEDD

TABLE 2. Mean Results

Innovations & Volume 9, Number 6, November/December 2014 Annuloplasty Rings in Mitral Valve Repair

403


404 Edwards Lifesciences

Shahin et al, 200541

4

Edwards Lifesciences Edwards Lifesciences

Chung et al, 200726

Lee et al, 199733

Lee et al, 199733

6

7

8

Edwards Lifesciences Edwards Lifesciences

Bevilacqua et al, 2003

Sakamoto et al, 200638

Deloche et al, 199028

Perier et al, 199736

9

10

11

12

Genesee Med. Medtronic Medtronic Medtronic V V V

Gillinov et al, 200031

Lee et al, 199733

Chang et al, 200725

Chung et al, 200726

Makhija and Desai, 200934

Bevilacqua et al, 200320

Borghetti et al, 200021

Scrofani et al, 199639

14

15

16

17

18

19

20

21

Edwards Lifesciences Edwards Lifesciences Edwards Lifesciences Edwards Lifesciences Medtronic Medtronic SJM Sorin Group

Chan et al, 200624

Raffoul et al, 199837 41

Shahin et al, 2005

Lange et al, 200832

Fasol et al, 200429

Seguin et al, 199640

Bruno et al, 200922

24

25

26

27

28

29

30

Edwards Lifesciences

Accola et al, 2005

Carpentier et al, 199523

22

23

Memo 3D

Seguin

CG-Future

CG-Future

Physio

Physio

Physio

Physio

Physio

Pericardium

Pericardium

Pericardium

Duran AnCore

Duran AnCore

Duran AnCore

Sculptor

Edwards Lifesciences Cosgrove-Edwards

Cosgrove III et al, 1995

13

19

Classic

Classic

Classic

Edwards Lifesciences Cosgrove-Edwards


20

27

Classic

Classic

Classic

Classic

Edwards Lifesciences Classic and Physio


Borghetti et al, 2000

5

Classic

Classic

Classic

Classic

Ring

63

50

40

437

43

190

97

137

492

113

23

56

73

141

170

30

197

150

208

113

112

77

155

36

153

21

53

242

11

186

Study Size, n

70.2 T 10.3

58

68.3 T 8.1

63.7 T 13.3

62.0 T 12

57 T 14

56

49.1

64.2

58.1 T 12.09

62.0 T 8.0

64.4 T 9.7

NA

53.0 T 13.0

50.3

65.8 T 9.4

58.0 T 13.0

57.8 12.7

59.4 T 10.5

56.6

53 T 15

61.7 T 12.6

65.0 T 9.5

65.3 T 11.8

53.0 T 13.0

53.0 T 16.0

65.6 T 10.6

62.7

53.5 T 11.5

49.4

Age, y

61.9

80

70

65.7

65

84.5

66.7

65

71.3

100

91.4

100

100

100

62.9

66.7

73

75

92.0

100

90.0

100

72.3

77.8

100

90.5

65

100

100

69.4

DEG, %

11.2 T 5.1

12.1

16.5 T 5.7

25.2 T 13.2

61,4 T 20.1

23 T 13

46.8

6 T 18

38.5

32.41 T 20.09

41.0 T 12.0

35.6 T 18.7

44.4 T 49.2

28.4 T 19.3

46.6

18.0 T 5.0

40.8 T 12

8.1 T 3.6

40.8 T 1.2

158

60.8

35.6 T 18.7

39.9 T 23.2

15.2 T 6.7

42.7 T 26.5

46.0 T 15.0

61.2

96

30.0

46.6

Follow-up, mo

100% Q3+

3.6 T 0.8

NA

85.6% Q3+

NA

3.16 T 0.5

NA

NA

100% Q3+

100% Q3+

100% Q3+

NA

74% Q3+

100% Q3+

NA

NA

3.6 T 0.7*

3.7 T 0.7*

NA

NA

74% Q3+

NA

NA

NA

100% Q3+

100% Q3+

NA

NA

NA

NA

Preoperative MR

73.1% 0+; 26.9 e 2+

0.4 T 0.3

24 m 73.7% 0+; 26.3 e 2+

41.2% 0+; 54.3 e 2+

NA

10.5 e 2+ 0.26 T 0.46

13.8% 0+; 86.3 e 2+

94.7% 0+; 5.3 e 2+

100% e2+

84,1% e1+ (4+)

NA

NA

82.3% 0+; 9.5% e2+

NA

NA

NA

0.1 T 0.4*

0.6 T 0.7*

74.1% no MI; 25.9 e 2+

74% no MI

83.3% no MI

NA

NA

NA

NA

NA

NA

NA

NA

NA

Postoperative MR

*Values are presented as mean T SD. †Values are presented as mean. DEG % indicates fraction degenerative disease in the study population; MR, mitral regurgitation; NA, not available; degenerative; NYHA; New York Heart Association classification.

Semirigid

Flexible


Flameng et al, 200330

3



Okada et al, 199535

2

21


Chang et al, 200725

1

Rigid

Manufacturer

Reference

Insert Number

Ring Type

TABLE 4. DEG GroupVIndividual Study Results Regarding Patient Demographics, Follow-up, MR Grading, and NYHA Classification

76.2%

NA

NA

61%

67%

50.5%

45.7%

43.8%

49.8%

75.3%

2.6†

63.6%

31.5%

NA

62.9%

33.3%

NA

23.3%

68%

97%

NA

48.2%

76.1%

72.2%

NA

2.8†

60%

55%

19%

61.8%

5.2%

NA

7%

13.6%

33%

0

16.6%

0

2.60%

84.2 e 2

NA

NA

19.30%

NA

NA

NA

NA

NA

NA

24%

0

NA

NA

NA

NA

NA

18%

NA

0

NA

Preoperative Postoperative NYHA Q 3+ NYHA Q 3+

Khamooshian et al Innovations & Volume 9, Number 6, November/December 2014



Copyright * 2014 by the International Society for Minimally Invasive Cardiothoracic Surgery NA NA

NA 61.4 T 5.0 56

66

NA

NA

60.6 T 10.3

NA

3

4

5

6

7

37.83 T 4.43

NA 44.69 T 9.12

58.5 T 9.1 59.5 T 6.0

45.7 T 11.7

58.5 T 9.1

NA

NA

19

20

21

NA 60.0 NA 52.6 T 11.5 49.8 T 19.7 NA 58.2 T 10.6

NA

65.6 T 15

NA

57.9 T 15.3

46.7 T 16.9

NA

46.9 T 12.9

24

25

26

27

28

29

30

(1 y) 56.0

(1 y) 50

23

NA

NA

22

NA

31 T 5

41.3 T 5.4

59 46.5 T 11.1

61.4 T 9.5

18

39.7 T 6.0

NA

42.5 T 3.9

NA

NA

NA

NA

NA

NA

NA

39.6 T 7.7

NA

32.2 T 8.1

NA

35.0 T 9.3

36.4 T 7.7

59.3 T 6.9

NA

64.5 T 6.2

NA

NA NA

NA

NA

NA

NA

66.38 T 9.12

NA

60.4 T 5.9

NA

NA

59.4 T 11.7

NA

NA

NA

61.4 T 9.4

NA

NA

59.8 T 5.0

NA

NA

NA

39.0 T 11.1

NA

NA

NA

34 T 0.9

NA

33.5

37.1 T 8.2

17

NA 45.8 T 11.9

NA 60.2 T 11.5

NA

63.2 T 11.9

NA

NA

NA

NA

NA

33.5 T 0.9

NA

NA

34.5

16

NA

NA

38.2 T 7.7

NA

NA

40.8 T 5.2

NA

NA

41.8 T 9.0

NA

NA

38.9 T 9.7 32 T 5

NA

63.0 T 8.0

58.3 T 12.3

Preoperative LVEDD

NA

37.0 T 10.0

37.1 T 9.3

Postoperative LVESD

15

NA

NA

12

NA

NA

11

NA

NA

NA

65 T 12

10

14

59 T 16.3

68.7 T 12.7

9

13

NA 54.5 T 10.8

NA

54.5 T 10.8

8

NA

NA

NA

59.0 T 10.0

NA

2 NA

49.2 T 11.7

59.0 T 12.3

62.5 T 11.8

1

Preoperative LVESD

Postoperative LVEF

Preoperative LVEF

Insert Number

50.6 T 12.2

NA

50.4 T 9.5

52.5 T 7.9

51.5 T 8.26

NA

NA

NA

NA

53.4 T 5.61

45 T 5

52.6 T 0.9

NA

NA

50.4 T 8.2

NA

NA

NA

NA

NA

NA

52.0 T 0.9

NA

NA

NA

47.0 T 5.0

55.1 T 8.4

NA

NA

48.8 T 8.3

Postoperative LVEDD Survival, %

NA

NA

1.5 y: 89.9 T 2.5

5 y: 97.5 T 1.4

1 y: 95.1

1 y: 96

2 y: 95

4 y: 89.9 T 2.2

5 y: 89.0 T 4.8

NA

4 y: 93.6; 8 y: 91.0

1 y: 98

NA

100

NA

4 y: 97 T 1.3

NA

NA

8 y: 90.8 T 1.9; 4 y: 93.8 T 2.3

1 y: 98.5

5 y: 89.7; 1 y: 97 7 y: 67.9 T 4.6; 4 y: 81.5 T 2.1

NA

4 y: 100

5 y: 79.5 T 7.7

7 y: 92.2 T 0.6

5 y: 87.7 T 7.9

7 y: 67.9 T 4.6; 4 y: 81.5 T 2.1;

4 y: 100

5 y: 91.0 T 7.1

7 y: 94.3 T 3.06

5 y: 95.7 T 2.3

NA

10 y: 75.7 T 7.2; 5 y: 91.4 T 2.8

1.5 y: 86.3 T 6.4

1 y: 97.0 4 y: 95 (95% CI, 93-96)

4 y: 93.0

1 y: 98.0

6 y: 95 T 4; 5 y: 95 T 4

15 y: 91; 10 y: 91; 5 y: 94

15 y: 71.17 T 3.65; 10 y: 82; 5 y: 92 6 y: 87 T 7; 5 y; 90; 1 y: 97 T 2

10 y: 96.0 T 2.0; 5 y: 96.0 T 2.0

10 y: 92.0 T 3.0; 5 y: 92.0 T 3.0

5 y: 95 T 4.4

NA

5 y: 95.8 T 3.9

5 y: 89.7 T 3.1

5 y: 91.6 T 2.9

4 y: 100

1.5 y: 88.1 T 6.7

4 y: 100

5 y: 79.0 T 5.7

NA 8 y: 94.2 T 2.3; 5 y: 96.1 T 1.3%

NA

10 y: 95.5 T 3.9; 5 y: 99.5 T 0.5

Freedom From Reoperation, %

8 y: 90.9 T 3.2; 5 y: 94.7 T 1.7

10 y: 85.9 T 4.9; 5 y: 95.6 T 1.7

Values are presented as mean T SD. CI indicates confidence interval; DEG, degenerative group; LVEDD, left ventricular end-diastolic diameter; LVEF, left ventricular ejection fraction; LVESD, left ventricular end-systolic diameter; NA, not available.

Semirigid

Flexible

Rigid

Ring Type

TABLE 5. DEG GroupVIndividual Study Results Regarding Cardiac Function and Dimensions, Survival, and Freedom From Reoperation

Innovations & Volume 9, Number 6, November/December 2014 Annuloplasty Rings in Mitral Valve Repair

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TABLE 6. ICM GroupVIndividual Study Results Regarding Patient Demographics, Follow-up, MR Grading, and NYHA Classification Ring Type Rigid

Flexible

Semirigid

Insert Number

Reference

Manufacturer

Ring

Study Size, n

Age, y

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24

McGee et al, 200449 Sajja et al, 200953 Filsoufi et al, 200716 Onorati et al, 200952 Makhija and Desai, 200934 Nicolini et al, 200650 Silberman et al, 200954 Tahta et al, 200256 Tekumit et al, 200957 Szalay et al, 200355 Szalay et al, 200355 McGee et al, 200449 Chiappini et al, 200845 McGee et al, 200449 Omay et al, 200951 Bax et al, 200442 Braun et al, 200843 Chen et al, 200944 Onorati et al, 200952 Silberman et al, 200954 Fattouch et al, 200946 Geidel et al, 200848 Onorati et al, 200952 Formica et al, 200747

Edwards Lifesciences Edwards Lifesciences Edwards Lifesciences Edwards Lifesciences Medtronic Medtronic Medtronic Medtronic Sorin Group V V Edwards Lifesciences Edwards Lifesciences V V Edwards Lifesciences Edwards Lifesciences Edwards Lifesciences Edwards Lifesciences Edwards Lifesciences Edwards Lifesciences Edwards Lifesciences Medtronic Medtronic

Classic Classic IMR es IMR ETlogix Duran AnCore Duran AnCore Duran AnCore Duran AnCore Carbomedics Sovering Flexible posterior band Flexible posterior band Cosgrove-Edwards Cosgrove-Edwards Pericardium Pericardium Physio Physio Physio Physio Physio Physio Physio CG-Future CG-Future

122 127 40 25 60 61 117 100 44 91 30 396 78 67 36 51 100 42 22 52 48 100 17 85

NA 57.94 T 9.74 68.0 T 10.0 69.5 T 1.4 NA 69.2 T 7.0 65.0 T 10.0 67 T 11 64.2 T 7.6 66.0 T 0.8 67.5 T 1.2 NA 69.5 T 7.8 NA 59 T 10 64.0 T 8.0 67.1 T 9.8 56.5 T 15.0 69.5 T 2.0 65.0 T 10.0 64 T 9 69 T 10 68.7 T 1.4 66.9 T 8.6

*Values are presented as mean T SD. †Values depicted as mean. Concomitant CABG % indicates fraction of concomitant CABG in study population; DCM, dilated cardiomyopathy; ICM, ischemic/dilated cardiomyopathy; MR, mitral regurgitation; NA, not available; NYHA, New York Heart Association classification; reop&survival, follow-up length of the reoperations and survival combined.

Pannus Formation Chung et al26 published an article in 2007 demonstrating long-term outcomes after annuloplasty with the CarpentierEdwards (CE) Classic and Duran flexible ring in patients with degenerative disease. Five-year results were comparable between the rings in terms of left ventricle (LV) function, MR-free survival, overall survival, and reoperations. However, a significant difference in mitral stenosis (MS) between the 2 groups was detected after 5 years [MS-free survival, 91.2 T 2.8 and 65.1 T 10.7 (P = 0.011) for CE and Duran group, respectively]. This was probably caused by pannus formation. In the multivariate analysis, ring type was the only independent determinant for MS development. Other studies and case reports58Y63 have also reported MS caused by pannus formation in patients with degenerative MV disease treated with Duran rings, all needing MV replacement. In a series of 478 patients,59 4 were observed with unremovable dense fibrous tissue overgrowth on the ring and MV leaflets causing MS. Histology showed thickening of the atrial aspect of the leaflets with evidence of chronic inflammation originating from the annuloplasty ring. Possible causes for pannus formation occurring when using a Duran ring have been discussed by Chung et al.26 Before 1989, no templates were available for Duran rings, and surgeons were forced to implant the ring without it excessive crimping of the ring with each of the annuloplasty sutures might have played a role in the MS. A second factor could be caused by the tendency to use a smaller

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Duran ring because they are sized by the intertrigonal dimensions, whereas for example, the CE Classic ring is sized by intercommissural dimensions. This theory was not supported by their multivariate analysis in which ring size was found not to be a risk factor for the development of MS. It is also known that prolonged exposure to synthetic materials causes a chronic inflammation, which is most likely the mechanism behind pannus formation. However, it is odd that only Duran rings have shown this phenomenon, despite the same polyester covering that is used in the Duran and CE Classic rings. Whether these mentioned cases are incidents, clinicians should pay additional attention to MS in the follow-up of patient when implanting a Duran ring.

Pericardium Annuloplasty A relatively new development is the use of biologic posterior bands made of glutaraldehyde-treated pericardium. Borghetti et al21 conducted a retrospective study in 44 patients with a prolapsed posterior MV leaflet treated with either autologous pericardium or a CE Classic ring. Echocardiographic results were similar between the rings; however, during exercise, rigid rings were suggestive of a more restrictive blood flow. Annular downsizing could not be a possible cause since the implantation of large rings in these series. At peak exercise, there was an 8% reduction of LVED volume only in the rigid ring group. In accordance with the experimental study of van





TABLE 6. (Continued) Etiology

Concomitant CABG, %

Follow-up, mo

Preoperative MR

Ischemic Ischemic Ischemic Ischemic Ischemic Ischemic Ischemic Ischemic Ischemic Ischemic DCM Ischemic Ischemic Ischemic Ischemic Ischemic Ischemic DCM Ischemic Ischemic Ischemic Ischemic Ischemic Ischemic

95 100 68 100 45 100 100 100 100 86 10 95 100 95 100 100 100 0 100 100 100 100 100 100

27.6 (reop&survival) 19.65 T 13.21 15.0 T 40.0 17.8 T 12.9 46.8 T 34.8 39.4 T 18.9 58 T 30 35.8 T 15.6 13.14 T 4.66 26 T 20.1 18.7 T 2.4 27.6 (reop&survival) NA 27.6 (reop&survival) 18 T 1 24.0 51.6 T 16.8 31.9 T 16.1 25.9 T 16.6 14.0 T 7.0 32 T 18 30 T 12 25.7 T 13.6 14.3 T 9.8

91.0% Q3+ 100% Q3+ 100% Q3+ 100% Q3+ 67.3% Q3+ 3.3 T 0.9* 3.0 T 1.0* 79% Q3+ 2.8* NA NA 82% Q3+ 100% Q3+ 93% Q3+ 3.4 T 0.5* 3.4 T 0.6* 3.1 T 0.6* 3.6 T 0.5* 100% Q3+ 3.0 T 0.9* 2.0* 3.6 T 0.5* 100% Q3+ 2.5 T 0.6*

Rijk-Zwikker et al64 and Okada et al,35 this is suggestive of a reduced LV filling during stress conditions. Moreover, the LVEF increased in the pericardium group after exercise, whereas the rigid group maintained at a rest value. The authors conclude that pericardium annuloplasty seems to be superior to rigid prosthetic rings. These results have to be interpreted with caution because this series used a very strictly selected study population. Other studies showed favorable results too; Scrofani et al39 treated 113 patients with degenerative disease with posterior pericardium annuloplasty. After a mean T SD follow-up of 32.41 T 20.09 months, 84.1% of the patients were asymptomatic and had no-to-mild residual MR. The 5-year freedom from reoperation rate was 89.7%, whereas other series21 showed a freedom of reoperation of 100%. Unfortunately, other studies suggest that this technique can also jeopardize reproducibility and durability of MV repair because a significant difference in 5-year freedom from reoperation was detected between the prosthetic ring and pericardium group (95.0% vs 79.50%, respectively).20 Moreover, the recurrence rate of MR of grade 3+ or higher was significantly higher, which is in accordance to a study conducted by the Cleveland Clinics in 585 patients with functional ischemic MR (66%).49 The prosthetic annuloplasty group in this larger study showed 25% MR of grade 3+ or higher in the first 6 months postoperatively. Although the differences are quite significant, this study has to be interpreted with caution because only 17% of the postoperative echocardiograms were made after 1 year, yet

Postoperative MR 75.0% e2+ 52% 0+; 48% e1+ 61.0% 0+; 39 e 2+ NA 89.9% 0+; 5.0% e2+ 0.9 T 0.8* 1.25* 42% 0+; 53% e2+ 25% 0+; 67.5% e2+ 1.0* 0.6* 75.0% e2+ NA 66.0% Q3+ 0.5 T 0.6* 0.8 T 0.8* 0.8 T 0.7* NA NA 0.7* 100% e1+ 0.4 T 0.6* NA NA

Preoperative NYHA

Postoperative NYHA

70.0% Q3+ 3.16 T 0.57* NA 3.3 T 0.6* 63.4% e2+ 3.3 T 0.9* 3 T 0.9* 72% Q3+ 2.82 T 0.72* 3.2 T 0.04* 3.3 T 0.1* 59.0% Q3+ NA 67.0% Q3+ 2.6 T 0.9* 3.4 T 0.8* 3.0 T 0.8* 3.2 T 0.4* 3.3 T 0.7* 3.0 T 1.0* 2.3 T 1.1* 3.5 T 0.5* 3.4 T 0.5* 2.04 T 0.9*

NA 1.06 T 0.24* NA 1.1 T 0.6* 78.3 e 2+ 0.9 T 0.8* 1.9* 81% e2+ 2.23 T 0.5* 1.7 T 0.07* 1.8 T 0.2* NA 100 e 2+ NA 1.1 T 0.5* 1.3 T 0.4* 1.6 T 0.6* 1.3 T 0.6* 1.2 T 0.5* 1.6* 0.6 T 0.8* 1.4 T 0.5* 2.1 T 0.9* 1.25 T 0.6*

the results are extrapolated to 5 years. A recent report51 however showed very different results in ischemic MR. After a mean T SD follow-up of 18.0 T 1.0 months, MR grade decreased from 3.4 T 0.5 to 0.5 T 0.6 in a study population of 36 patients. All patients underwent concomitant CABG. There were no reoperations, and only one late death occurred, suggesting pericardium annuloplasty is not per se inferior. Seemingly there are conflicting results regarding posterior pericardial annuloplasty. Surgeons should be cautious for higher MR recurrence and reoperation rates. As mentioned earlier, it has been suggested that the entire MV annulus is susceptible to dilation,65Y69 which could be a possible explanation for some of the inferior results when posterior pericardium annuloplasty is applied. There is no closing evidence of pericardial annuloplasty jeopardizing MV repair; however, conflicting results in the literature and excellent MV repair results with prosthetic materials allow a negative recommendation toward using this form of annuloplasty.

Semirigid Rings Semirigid rings are the most ‘‘intuitive’’ form of annuloplasty and come in planar, saddle-shaped, and open forms. More surgical centers have adopted these rings, especially the CE Physio and its successor Physio II. The results of clinical studies are quite satisfying, although not better than other ring types. A Dutch study41 performed one of the few randomized trials


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TABLE 7. ICM GroupVIndividual Study Results Regarding Cardiac Function and Dimension and Survival Insert Number

Preoperative LVEF

Postoperative LVEF

Preoperative LVESD

Postoperative LVESD

Preoperative LVEDD

Postoperative LVEDD

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24

NA NA 39 T 14 41.3 T 9.8 38.3 T 14.1 28.9 T 5.2 NA 82% e50% 42.90 T 7.72 25 T 0.5 23 T 14 NA 42.4 T 12.4 NA 37.9 T 6.1 31 T 8 30 T 8 31.4 T 12.9 39.1 T 7.2 NA 42 T 10 31 T 9 40.2 T 7.9 43.8 T 11

NA NA 40 T 11 45.7 T 6.4 41.3 T 12.7 35.4 T 8.1 NA NA 45.26 T 7.28 NA NA NA 51.7 T 10.9 NA 43.7 T 7.3 NA 45 T 15 43.5 45.0 T 8.7 NA 48 T 8 41 T 9 41.3 T 9.8 50 T 4.9

NA NA NA 52.4 T 6.0 NA 35.9 T 3.5 42 T 8 NA 43.5 T 8.4 50 T 0.9 53 T 1.2 NA NA NA 39.7 T 5.8 51 T 10 46 T 11 55.4 51.4 T 6.5 44 T 9 45 T 8 NA 51.1 T 13.0 44.5 T 8

NA NA NA 48.3 T 5.9 NA

NA NA NA 65.1 T 4.6 NA 40.5 T 4.5 57 T 6 NA 54.9 T 7.2 64.0 T 0.9 65.0 T 1.0 NA NA NA 53.2 T 5.6 64.0 T 8.0 60.0 T 9.0 66.0 64.6 T 4.5 56.0 T 8.0 59 T 8 NA 64.1 T 8.3 61 T 8

NA NA NA 61.4 T 5.1 NA

40.2 T 8 NA 39.8 T 5.9 NA NA NA NA NA 34.6 T 6.5 43 T 12 39 T 11 44.9 49.1 T 6.5 39.1 T 10 37 T 5 NA 49.8 T 13.5 40 T 7

54.3 T 7.0 NA 52.0 T 6.4 NA NA NA NA NA 50.9 T 5.5 57.0 T 11.0 54.0 T 9.0 57.7 60.8 T 6.5 53.3 T 7.0 52 T 7 NA 64.5 T 8.2 56 T 7

Survival, % 5 y: 60.0; 1 y 82.0 NA 1 y: 92.0 2 y: 95.7 T 4.5 7 y: 93.0 T 2.9 3-5-6 y: 87.0; 1 y 94 5 y: 75.0; 3 y: 79.0; 1 y 84.0 8 y: 42; 5 y: 68.0; 1 y: 87 NA NA NA 5 y: 60.0; 1 y 82.0 5 y: 82.6 T 5.9 5 y: 60.0; 1 y 82.0 1 y: 97.2 NA 5 y: 71 T 5.1; 1 y 87 T 3.4 3 y: 79.2; 1 y 88.9 2 y: 95 T 4.9 5 y: 100.0 5 y: 93.7 T 3.1; 1 y: 95.8 T 2.3 2 y: 94 2 y: 100 1 y: 88.7

Values are presented as mean T SD. ICM indicates ischemic/dilated cardiomyopathy; LVEDD, left ventricular end-diastolic diameter; LVEF, left ventricular ejection fraction; LVESD, left ventricular end-systolic diameter; NA, not available.

regarding this subject in 96 patients with degenerative disease comparing the Carpentier Classic ring with the Physio ring. At the end of the follow-up (61.4 T 20.1 months), there were 16 deaths in the CE Classic group and 6 in the Physio group. Although the 16% difference in mortality was not significant, the authors consider this clinically important. Moreover, the absolute risk of death after 30 months was in favor of the Physio ring. No further differences were found in echocardiographic and clinical data. McCarthy et al17 compared the Physio ring with the new Edwards Myxo-ETlogix ring. The etiology specific ring has been designed with a large orifice, which reduces the risk of systolic anterior motion and theoretically the use of a sliding plasty, which could make MV repair less complex and more generalizable. This initial study shows the capability of the Myxo-ETlogix ring to be used as an alternative for the conventional annuloplasty rings. Another D-shaped planar semirigid ring, the Genesee Sculptor, was compared with the CE Classic ring by Lee et al.33 No significant differences in mortality and complications could be detected. All further studies investigating semirigid rings are noncomparable follow-up studies with overall good results. For detailed study information, see Tables 4 through 7. Semirigid rings have also been investigated in ischemic disease, usually combined with CABG. Postoperative MR using a Physio ring in a study conducted by Silberman et al54 was significantly lower compared with the Duran flexible ring. Mitral regurgitation in the Physio and Duran groups improved from 3.2 T 0.8 and 3.1 T 1.0 to 0.7 T 1.0 and 1.25 T 1.0,

408

respectively. In the Duran group, 35% of the patients remained with moderate-to-severe MR, as opposed to 15% in the rigid group. Age and ring type were predictors of late mortality. The 5-year mortality in the Duran group was 75%, whereas no deaths occurred in the Physio group. This is a surprising result because in other studies, mortality rates of both groups are much more comparable. Onorati et al52 performed a study comparing restrictive semirigid posterior bands (Medtronic CG-future), symmetrical rings (Edwards Physio), and asymmetrical rings (Edwards IMR ETlogix). In this experiment, the use of semirigid bands carried the highest risk for MR recurrences (55.6% T 12.7%, 92.3% T 7.4% and 94.1% T 5%, respectively) with deleterious effects on functional status and echocardiographic. However, no differences were found in survival. Despite the undersizing, posterior bands are not effective enough in reducing the septolateral (SL) distance, which could explain the recurrence of MR. Thereby, the intertrigonal distance is capable of dilating in ischemic disease as we have stated before and could contribute to the recurrence of MR.

EXPERIMENTAL AND CORRESPONDING CLINICAL STUDIES Annular dilatation is one of the main mechanisms of MR and is effectively tackled by inserting an annuloplasty ring, which restores the anteroposterior ratio of 3:4, relieves tension from the leaflets,70 and prevents the annulus from dilating in





FIGURE 2. Degenerative group. Preoperative and postoperative outcomes stratified in subgroups (rigid, flexible, and semirigid). Depicted are the individual study results. LVEDD indicates left ventricular end-diastolic diameter; LVEF, left ventricular ejection fraction; LVESD, left ventricular end-systolic diameter. Copyright * 2014 by the International Society for Minimally Invasive Cardiothoracic Surgery

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FIGURE 3. Ischemic/dilated cardiomyopathy group. Preoperative and postoperative outcomes stratified in subgroups (rigid, flexible, and semirigid). Depicted are the individual study results. LVEDD indicates left ventricular end-diastolic diameter; LVEF, left ventricular ejection fraction; LVESD, left ventricular end-systolic diameter.

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the future. This concept of annulus reinforcement was first introduced by Lillehei et al71 in 1957 followed by Reed et al72 and Kay and Egerton73 who developed the suture annuloplasty technique. Carpentier was the first to develop the planar rigid Carpentier Classic ring in 1971.14 Until now, this D-shaped planar ring is one of the most used and investigated ring. Although MV repair with rigid rings provide very acceptable long-term results, the theoretical disadvantages caused by their fixed shape caused the development of other ring types. Rigid rings restore the annulus to its normal size and shape; however, the dynamics during the cardiac cycle is disturbed. Because of the possible clinical disadvantages, Duran et al74 developed in 1978 the first entirely flexible annuloplasty ring assuming it had a more physiologic effect on the annulus, hence the adaptation to the annular changes during the cardiac cycle. The cardiac pump function was expected to improve because of less interference with the muscular contractions. Moreover, the chance of suture dehiscence was thought to be less because of the diminished tension on the sutures. We like to discuss some clinical studies, experiments on healthy animals, and finite element models to evaluate the effect of rigid and flexible rings on valve function.

Rigid Versus Flexible Rings Yamaura et al75Y77 conducted some multiplane echocardiographic studies in patients with flexible and rigid rings. These studies demonstrated a planar MV configuration without intercardiac phase changes only in valves reinforced by rigid rings. The mitral annular area (MAA) remained unchanged between systole and diastole, whereas it decreased significantly with flexible rings.77 In comparison with healthy volunteers, flexible rings did not alter the nonplanarity and motion of the MV. These results are in correspondence to the study conducted by Dall’Agata et al78 (Cosgrove-Edwards vs CE) who also demonstrated the conservation of the natural MV motion when flexible rings are implemented. van Rijk-Zwikker et al64 came to the same conclusion in pigs; flexible rings interfered less with the MV motion and annulus size compared with rigid rings. Moreover, a slightly better pump function in a perfusion model with isolated porcine hearts with flexible Duran rings was seen. The effects of rigid rings could be explained as a reduction of pump function caused by LV filling impairment, which limits stroke volume, especially when the cardiac output is high. The authors suggest that flexible rings are more suitable for active patients with a normal pump function. Although this is difficult to demonstrate in a clinical situation, David et al79 investigated the effect of ring type on left ventricular function (LVF) of patients with chronic degenerative disease. The data indicate a better LVF 2 to 3 months postoperatively in patients with a flexible ring. Left ventricular enddiastolic dimension and LVF decreased in both ring groups; however, the LVESD and LVES volume decreased only in patients with a flexible ring. A possible explanation is the impairment of stretching and shortening of the proximal part of the basoconstrictor muscles when using a rigid ring. Another important finding was the better systolic-volume relationships during exercise in patients with a flexible ring. Although this is indicative for a better LVF when using a flexible ring, the advantage disappears after myocardial remodeling 1 year postoperatively. Similar results were found by Okada et al35 who found


only an increase in fractional shortening during exercise with a Duran ring, whereas the Carpentier Classic group remained unchanged. In addition, although it did not reach a significant level, the data show a larger LVED volume, smaller LVES volume, and better LVEF with the flexible ring. In accordance with van Rijk-Zwikker et al,64 this suggests an impaired diastolic filling of the LV. The peak velocity across the MV was significantly larger in the rigid group during exercise. A change in MAAwas only seen in the flexible ring group, while the posterior mitral annulus contracted and moved anteriorly. These data suggest that implantation of a flexible ring results in a larger effective orifice during exercise compared with rigid rings and causes less interference with the normal MV motion, which is in accordance to other studies.75Y78 In an in vitro study, Arita et al80 showed similar results. The orifice area obtained with the flexible ring exceeded that with the rigid ring, implying a difference in diastolic performance between the rings. The shearing force and bending moment were greater in the rigid ring as a result of the inhibited movement. High values indicate stress on the ring and sutures. The authors recommend placing additional stitches at the trigone and posterior regions of rigid annuloplasty rings to minimize the risk of ligature failure. In a finite element study implemented by Kunzelman et al,81 all the stresses were increased, particularly in the posterior mitral valve leaflet region. When applying a flexible ring, the cooptation and stresses were returned closer to normal. These results correspond to the work of Arita et al.80 These studies indicate that in both clinical and experimental settings, rigid rings impair the natural motion of the MV, impair the LVF, and make the annulus planar. Although studies performed by the Stanford University group show other, surprising results, after 1 and 6 weeks, no difference in LV mass, hemodynamics, as well as systolic and diastolic function in conscious closed-chest dogs could be found.82 In anesthetized, open-chest dogs, rigid fixation of the mitral annulus did not alter global or regional LV systolic function.83 Dagum et al84 of the same institution implemented a powerful study in sheep using radiopaque markers sutured equidistantly around the mitral annulus to track 3 dimensional geometric changes of a partial posterior flexible ring (Saint Jude Medical Tailor ring). Data of a previous experiment85 using a flexible Duran ring and a control group were used as a comparison in this study. The MAA, commissure-commissure (CC), and SL dimensions changed from diastole to systole in the control group and were significantly larger compared with the ring groups. Surprisingly, both the partial posterior and the complete flexible ring completely abolished these changes by remaining in a fixed position. The MAA and CC dimensions were larger in the Tailor posterior ring compared with the Duran ring, whereas the SL dimensions did not differ. The difference in area reduction between the rings can be explained by the fact that the Tailor ring preserved more of the elliptical annular shape than did the Duran ring, although ring sizes were selected on the basis of the same criteria. Both rings allowed the anterior annulus to elevate and the complete annulus to flex during systole, although the results of the Tailor ring group were similar as the control group. These results are in contrast to the previously mentioned studies in which only rigid rings interfere with the MV motion.


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Semirigid Versus Flexible Rings As mentioned earlier, the Stanford University group has performed several experiments on sheep using radiopaque markers and cine fluoroscopy. These highly valuable studies give us much insight about the MV dynamics. Five studies85Y89 ranging in time from 1998 to 2005 have been performed using the semirigid CE Physio and flexible Medtronic Duran ring versus control animals. The 3-dimensional saddle shape of the MV can be measured by the annular height (AH)Ycommissural width ratio (AHCWR). This is an excellent surrogate of valve geometry for comparing the nonplanarity of the valve when different annuloplasty rings are used. The 2005 study87 showed a greater AH in the Duran and control groups compared with the Physio group; however, both rings allowed systolic increase in AH and a substantial reduction in the commissural width. Consequently the AHCWR of the Duran group matched the one in the control group. In contrast, the Physio group had a relatively low AHCWR, hence the reduced AH. This experiment illustrates well the capability of flexible rings to maintain the native AH better than Physio rings and permit normalization of AHCWR throughout the cardiac cycle. The MAA, posterior perimeter, SL, and CC dimensions did not change during the cardiac cycle in both ring groups, whereas the control group changed dynamically.85 As concluded before, it is surprising that the flexibility of the Duran ring was not confirmed by this study, as all the valve dimensions stayed fixed. This would indicate that annuloplasty, whether semirigid or flexible, freezes the annulus and impairs the mobility of the central posterior leaflet.89 However, the anterior leaflet motion is not restricted with a semirigid or flexible ring.88 Ryan et al90 compared the rigid saddle-shaped Medtronic Profile 3D with the less saddle-shaped semirigid Physio ring. In systole, both rings reduced the SL dimensions and MAA. The Physio ring decreased the AHCWR by 43%, whereas the Profile 3D increased it by 23.8%. This indicates that an extreme saddleshaped ring such as the Profile 3D maintains normal annular geometry, whereas the less saddle-shaped Physio ring markedly reduced annular nonplanarity. Whether this influences clinical outcome is uncertain. Green et al86 postulated that in sheep hearts, semirigid or flexible fixation of the mitral annulus has no measurable effect on global or regional systolic LVF, even after inotropic stimulation. These results are contradictory to the experiments of van Rijk-Zwikker et al64 and David et al79 and only complicate the subject. There is debate whether rigid rings impair the LVF and the natural movement of the MV during the cardiac cycle. Although some investigators suggest that mitral annular configuration, dynamics, and systolic function are more physiologic in patients with flexible rings compared with rigid rings,35,64,75Y77,79Y81,87 other studies showed no changes in annular dynamics during the cardiac cycle with flexible rings84 and no impairment of systolic function with rigid rings.82,83 According to Timek and Miller,91 the differences between studies can be explained by many reasons. First of all, it seems simple to measure the MAA, dynamics, and geometry, but then again, in practice, it is a major challenge in both human and experimental settings because the mitral annulus is not a welldefined anatomic structure, which is difficult to image and track accurately. Another major cause of the inconsistencies is

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the measuring technique. Two-dimensional and 3-dimensional echocardiography in clinical situations differs from measurements with radiopaque markers in experimental settings. The use of the latter is the most accurate technique; however, it can only be used in animal models, which have healthy valves. Not only are there intertechnique differences, but intratechnique variations also exist between studies.31,78 Species, patient condition, left ventricular loading conditions, and inotropic state could be also responsible for the discrepancies.

Ischemic/Dilated Cardiomyopathy In functional MR (FMR), valve competence is commonly restored by undersized annuloplasty rings, which reduce the valve native anteroposterior dimensions. In case of severe MR, this solution may be insufficient. Annuloplasty rings specially designed for FMR (Carpentier-McCarthy-Adams IMR ETlogix and GeoForm) could lead to better results. The GeoForm ring has been introduced for the correction of FMR characterized by symmetric papillary muscle displacement and centrally positioned regurgitant jets like in dilated cardiomyopathy. The intercommissural distance of this ring is equivalent to traditional rings; however, the anteroposterior distance is reduced by 41%. Moreover, to enhance anteroposterior distance, the ring has an elevated P2 segment to pull the posterior leaflet upward (atrially) and inward toward the A2 segment. This new prosthesis has potentially the benefit of less severe undersizing and therefore maintaining a normal aortic valve mechanics. Votta et al compared 3 sizes (32, 30, and 28) of the GeoForm ring and the Physio ring in a finite element study, showing that the GeoForm ring leads to a better valve competence. Three degrees of dilated cardiomyopathyrelated FMR were simulated by progressively displacing the papillary muscles apically (1, 3, and 5 mm) at the systolic peak. Aggressive undersizing in both rings (28-mm rings) had the best reduction in regurgitation area; for 1-, 3-, 5-mm papillary muscle displacement, the regurgitation area reduction was 77%, 81%, and 89% as well as 43%, 60%, and 57%, for the GeoForm and Physio ring, respectively. The GeoForm reduced the regurgitant area better than the Physio ring and resulted in a far better cooptation length and lower peak stresses. In an earlier study with the same technique, this group demonstrated that with the use of a dog boneYshaped ring, the regurgitant area was negligibly affected by papillary muscle displacement to a maximum of 4 mm.92 In contrast, the GeoForm ring highly augments stresses at the insertion point of the P2 posterior scallop progressively when smaller ring sizes are used.18 The geometrical distortion of the adjacent structures of the annulus caused by the ring is a drawback with possible major consequences. Although finite element studies are very useful in understanding the characteristics of different rings, interpretations should be made thoughtfully with respect to clinical settings. Bothe et al93 implanted a GeoForm ring in 12 adult sheep and used radiopaque markers and fluoroscopy to measure the MAA during the cardiac cycle. By removing the annuloplasty ring, the same sheep were used as internal controls. As expected, the MAA change was completely abolished with the rigid GeoForm ring. In case of asymmetric ischemic type IIIb dysfunction with restricted leaflet motion, the Carpentier-McCarthy-Adams IMR ETlogix ring could be a solution. In ischemic MR, the P2 and P3 segments are often asymmetrically restricted and lead




to an asymmetrical annular dilatation (dilated cardiomyopathy leads to symmetrical annular dilatation). This ring is asymmetrical with a slight dip at the P2-P3 segment to increase cooptation of the tethered P2-P3 segments. A recent clinical study in 140 patients with ischemic MR treated with the IMR ETlogix ring and complete revascularization showed an actuarial 4-year survival of 82%.94 Furthermore, MV geometry and competence were restored. Although the results of this study are satisfying, others warn for an increase in mean gradient across the MV, possibly inducing functional MS.95 It is known that in ischemic MR restrictive annuloplasty provides better results than does a conventional ring size. The Stanford University investigated partial annuloplasty rings using an animal model using radiopaque markers.96 Six sheep with normal hearts received a St. Jude Tailor partial flexible ring, and 7 sheep served as controls. At a mean T SD of 8 T 1 day postoperatively, the animals were studied with biplane video fluoroscopy and echocardiography. This was performed before and during acute posterolateral ischemia using balloon occlusion of the circumflex artery. The data demonstrate that the Tailor ring effectively fixes annular size throughout the cardiac cycle. Neither increase in annular SL dimensions nor dilatation of the muscular annulus could be detected. Therefore, no MR was seen. Unexpectedly, the ring abolished normal mitral dynamics and posterior leaflet motion, which was previously seen after implantation of complete ring.85,89 The authors state that although the Tailor ring is partial, no annular dilatation was observed after mimicking FMR, because of the stability of the fibrous annulus. Hence, possibly, only a reduction of the muscular annulus is necessary in FMR. Although the validity for this particular study is correct, the mitral fibrous annulus is capable of dilating in ischemic disease66Y69; therefore, we should be cautious with implementing partial rings in patients with ischemically affected hearts.

CONCLUSIONS Today, there is hardly any consensus regarding the choice of annuloplasty ring types. Although many discrepancies exist in experimental studies, our conclusions from a large literature study are as follows. (1) Planar rigid rings negatively influence the annular geometry during the cardiac cycle more than flexible rings do. (2) Semirigid rings are more undefined and fall somewhere in between rigid and flexible rings. (3) The nonplanarity of the annulus is strongly influenced by flat rigid and semirigid rings, whereas nonplanar ring designs keep the 3-dimensional configuration of the annulus intact. Seemingly, the more extreme the curves of the prosthetics are, the better the nonplanar configuration of the MV will be preserved. (4) Although being a very rare and not well-understood phenomenon, Duran rings have been mentioned in the literature to possibly cause MS because of pannus formation. (5) Pericardium annuloplasty is associated with a higher MR recurrence rate in some studies and is therefore not recommended. (6) In ischemic MR, asymmetrical annuloplasty rings do not have much, if not any, additional positive influence on MR prevention. (7) It is not recommended to use partial posterior bands in ischemic MR, hence the higher recurrence of MR and no reverse ventricular remodeling. (8) In dilated cardiomyopathy, animal and finite element studies


suggest that rings with an extreme 3-dimensional configuration such as the GeoForm annuloplasty ring in combination with downsizing could provide better technical MV repair results than other ring forms. In practice however, implantation of these rings is very challenging, and experienced hands are needed. (9) From our analysis of available data in the literature, we conclude that ring type has no major influence on LVEF, LVEDD, LVESD, and NYHA class. (10) We do not believe that ring morphology and consistency play a major clinical role in MV repair based on the present literature. However, the lack of supporting evidence does not exclude the possible superiority or inferiority of a specific ring or ring type in the individual patient. Hence, until demonstrated otherwise, surgeons may choose their ring upon their judgment, tailored to specific patient needs.

STUDY LIMITATIONS The lack of a sufficient amount of studies in the ring group analysis results in a low power, which could make some results questionable. On the other hand, we believe that this is the strength of this study, as we have given a reflection of literature whichVat this momentVis inconclusive about a tailored ring selection. We would like to emphasize the need for better and more structured articles regarding annuloplasty rings, preferably prospective and randomized studies. The lack of data on recurrent MR in the present studies, for example, makes a comparison of this crucial variable almost impossible.

ACKNOWLEDGMENT The authors thank Lex A. van Herwerden, MD, PhD, for his support and expert input to the article.

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Restoration of normal left ventricular geometry after percutaneous mitral annuloplasty: case report and review of literature.

Repair of functional tricuspid regurgitation: comparison between suture annuloplasty and rings annuloplasty.

The viable mitral annular dynamics and left ventricular function after mitral valve repair by biological rings.

Determinants of functional capacity after mitral valve annuloplasty or replacement for ischemic mitral regurgitation.

Additional tricuspid annuloplasty in mitral valve surgery results in better clinical outcome.

Left ventricular pseudoaneurysm after mitral valve replacement: Review of pseudoaneurysms late after mitral valve replacement.

Mitral Annular Dimensions and Geometry in Patients With Functional Mitral Regurgitation and Mitral Valve Prolapse: Implications for Transcatheter Mitral Valve Implantation.

Catheter-based edge-to-edge mitral valve repair after percutaneous mitral valve annuloplasty failure.

Papillary muscle relocation and mitral annuloplasty in ischemic mitral valve regurgitation: midterm results.

Mitral valve repair without mitral annuloplasty with extensive mitral annular calcification.

First-in-man transseptal implantation of a "surgical-like" mitral valve annuloplasty device for functional mitral regurgitation.

Doppler echocardiographic comparison of the Carpentier and Duran anuloplasty rings versus no ring after mitral valve repair for mitral regurgitation.

Tricuspid valve annuloplasty for functional regurgitation.

Accessory mitral valve tissue: an updated review of the literature.

Early evidence of beneficial effects of chordal preservation in mitral valve replacement on left ventricular dimensions.

Mycobacterium goodii endocarditis following mitral valve ring annuloplasty.

Mitral valve prolapse and ventricular arrhythmias.

Association between residual mitral regurgitation and left ventricular outflow obstruction after Carpentier ring mitral annuloplasty.

In-vivo analysis of selectively flexible mitral annuloplasty rings using three-dimensional echocardiography.

[Analysis of left ventricular performance after mitral valve replacement with a technique of preservation of all chordae tendineae: comparison with conventional mitral valve replacement or mitral valve repair].

Preoperative Three-Dimensional Valve Analysis Predicts Recurrent Ischemic Mitral Regurgitation After Mitral Annuloplasty.

Lifting posterior mitral annuloplasty for enhancing leaflet coaptation in mitral valve repair: midterm outcomes.

Ischaemic mitral regurgitation: The effects of ring annuloplasty and suture annuloplasty repair techniques on left ventricular re-remodeling.

Erratum to: Left ventricular pseudoaneurysm after mitral valve replacement: Review of pseudoaneurysms late after mitral valve replacement.