Sizing for Mitral Annuloplasty: Where Does Science Stop and Voodoo Begin?
2013; Elsevier BV; Volume: 95; Issue: 4 Linguagem: Inglês
10.1016/j.athoracsur.2012.10.023
ISSN1552-6259
AutoresWolfgang Bothe, D. Craig Miller, Torsten Doenst,
Tópico(s)Cardiac Structural Anomalies and Repair
ResumoThe implantation of an improperly sized annuloplasty ring may result in an incompetent valve after surgical mitral valve repair. Consequently, the procedure of ring size selection is considered critical. Although a plethora of sizing strategies are described, the opinions on how to select the appropriate ring size differ widely and often appear arbitrary (ie, without scientific justification). These inconsistencies raise the question where, with respect to ring sizing, science stops and voodoo begins. The implantation of an improperly sized annuloplasty ring may result in an incompetent valve after surgical mitral valve repair. Consequently, the procedure of ring size selection is considered critical. Although a plethora of sizing strategies are described, the opinions on how to select the appropriate ring size differ widely and often appear arbitrary (ie, without scientific justification). These inconsistencies raise the question where, with respect to ring sizing, science stops and voodoo begins. Dr Miller discloses financial relationships with Edwards Lifesciences, Abbott Vascular, and Medtronic.Annuloplasty rings are implanted primarily to restore a sufficient amount of leaflet coaptation with the hope that will provide a durable repair. A multitude of annuloplasty rings made by different manufacturers are available in various sizes. Annuloplasty rings determine shape and size of the mitral annulus after repair. As the implantation of rings of suboptimal size has been shown to adversely affect surgical results [1Mihaileanu S. Outflow tract obstruction and failed mitral repair.Circulation. 1994; 90: 1107-1108PubMed Google Scholar, 2Shah P.M. Raney A.A. Echocardiographic correlates of left ventricular outflow obstruction and systolic anterior motion following mitral valve repair.J Heart Valve Dis. 2001; 10: 302-306PubMed Google Scholar, 3Marwick T.H. Stewart W.J. Currie P.J. Cosgrove D.M. Mechanisms of failure of mitral valve repair: an echocardiographic study.Am Heart J. 1991; 122: 149-156Abstract Full Text PDF PubMed Scopus (76) Google Scholar, 4Magne J. Senechal M. Mathieu P. et al.Restrictive annuloplasty for ischemic mitral regurgitation may induce functional mitral stenosis.J Am Coll Cardiol. 2008; 51: 1692-1701Abstract Full Text Full Text PDF PubMed Scopus (152) Google Scholar, 5Levine R.A. Hung J. Otsuji Y. et al.Mechanistic insights into functional mitral regurgitation.Curr Cardiol Rep. 2002; 4: 125-129Crossref PubMed Scopus (87) Google Scholar, 6Levine R.A. Schwammenthal E. Ischemic mitral regurgitation on the threshold of a solution: from paradoxes to unifying concepts.Circulation. 2005; 112: 745-758Crossref PubMed Scopus (376) Google Scholar] (see following text for details), choosing the proper ring size has been described as critical 7Chen F.Y. Cohn L.H. Mitral valve repair.in: Cohn L.H. Edmunds L.H. Cardiac surgery in the adult. 2nd ed. McGraw-Hill, New York2008: 1013-1029Google Scholar, 8Carpentier A.F. Lessana A. Relland J.Y. et al.The “physio-ring”: an advanced concept in mitral valve annuloplasty.Ann Thorac Surg. 1995; 60: 1177-1186Abstract Full Text PDF PubMed Scopus (309) Google Scholar. Currently, the process of ring sizing is mostly performed by the application of ring sizers; however, we will describe several aspects of this step that limit the scientific value and make surgical success depend more on experience and judgment.Current Strategies to Size Annuloplasty Rings Are ContradictoryFor each individual ring model, manufacturers provide a specific sizer, which is widely used as a tool to determine the size of the annuloplasty ring based on the dimensions of the anterior mitral leaflet (AML). Some sizers consist of a handle holding a D-shaped platform that includes two notches. Both the dimensions of the platform and the distance between the notches may be used to determine ring size. Figure 1 describes the three different sizer dimensions that are usually used to determine annuloplasty ring size. One, notch-to-notch (N-N) distance (Fig 1A) is used to estimate either the commissure-commissure (C-C) or the intertrigonal distance. Annuloplasty rings are labeled with even numbered sizes (eg, all rings from Edwards Lifesciences [Irvine, CA], Medtronic Profile 3D or Colvin-Galloway [CG] Future band/ring [Medtronic Inc, Minneapolis, MN], St. Jude Medical [SJM] rigid saddle-shaped annuloplasty ring [RSAR], or Seguin [St. Jude Medical, Inc, St. Paul, MN]) or odd numbered sizes (eg, Medtronic Duran or SJM Tailor). In even numbered rings, the distance between the notches on the sizer usually indicates the distance between the commissures, whereas in odd numbered rings, the distance between the sizer notches indicates the intertrigonal distance. That is not true for the Medtronic Profile 3D or CG Future band/ring, which are evenly labeled, but sized to the intertrigonal distance (according to the manufacturer and Redmond and associates [9Redmond J. Christiansen D. Bergin C. et al.In-vivo motion of mitral valve annuloplasty devices.J Heart Valve Dis. 2008; 17: 110-118PubMed Google Scholar]). Two, area of the platform (Fig 1B) is used to measure either the bare area or the entire area of the mitral leaflets. And three, the S-L diameter of the platform (Fig 1C) is used to measure the height of the AML.Based on the underlying pathophysiology (structural or functional mitral regurgitation [FMR]) and individual repair preferences, strategies for ring sizing and size selection vary (Table 1). We performed a PubMed search using the search terms “annuloplasty ring” and “humans,” and selected all studies describing ring sizing and ring selection strategies using ring sizers between 1998 and 2012.Table 1Surgical Mitral Valve Repair TechniquesLeafletsAnnulusChordae TendineaePapillary MusclesLeaflet tissue resection [10Carpentier A. Cardiac valve surgery—the ”French correction.”.J Thorac Cardiovasc Surg. 1983; 86: 323-337PubMed Google Scholar]Annuloplasty ring insertionChordal replacement [10Carpentier A. Cardiac valve surgery—the ”French correction.”.J Thorac Cardiovasc Surg. 1983; 86: 323-337PubMed Google Scholar]PM relocation [25Kron I.L. Green G.R. Cope J.T. Surgical relocation of the posterior papillary muscle in chronic ischemic mitral regurgitation.Ann Thorac Surg. 2002; 74: 600-601Abstract Full Text Full Text PDF PubMed Scopus (253) Google Scholar, 26Ueno T. Sakata R. Iguro Y. et al.New surgical approach to reduce tethering in ischemic mitral regurgitation by relocation of separate heads of the posterior papillary muscle.Ann Thorac Surg. 2006; 81: 2324-2325Abstract Full Text Full Text PDF PubMed Scopus (18) Google Scholar, 27Langer F. Schafers H.J. Ring plus string: papillary muscle repositioning as an adjunctive repair technique for ischemic mitral regurgitation.J Thorac Cardiovasc Surg. 2007; 133: 247-249Abstract Full Text Full Text PDF PubMed Scopus (51) Google Scholar]Sliding leaflet technique [28Jebara V.A. Mihaileanu S. Acar C. et al.Left ventricular outflow tract obstruction after mitral valve repair Results of the sliding leaflet technique.Circulation. 1993; 88: II30-II34PubMed Google Scholar]Chordal cutting [29Messas E. Pouzet B. Touchot B. et al.Efficacy of chordal cutting to relieve chronic persistent ischemic mitral regurgitation.Circulation. 2003; 108: II111-II115PubMed Google Scholar]PM sling [30Hvass U. Tapia M. Baron F. Pouzet B. Shafy A. Papillary muscle sling: a new functional approach to mitral repair in patients with ischemic left ventricular dysfunction and functional mitral regurgitation.Ann Thorac Surg. 2003; 75: 809-811Abstract Full Text Full Text PDF PubMed Scopus (165) Google Scholar]Leaflet tissue extension [31Acar C. de Ibarra J.S. Lansac E. Anterior leaflet augmentation with autologous pericardium for mitral repair in rheumatic valve insufficiency.J Heart Valve Dis. 2004; 13: 741-746PubMed Google Scholar]Annular plication [32Burr L.H. Krayenbuhl C. Sutton M.S. The mitral plication suture: a new technique of mitral valve repair.J Thorac Cardiovasc Surg. 1977; 73: 589-595PubMed Google Scholar]Chordal shortening [33Gillinov A.M. Cosgrove D.M. Blackstone E.H. et al.Durability of mitral valve repair for degenerative disease.J Thorac Cardiovasc Surg. 1998; 116: 734-743Abstract Full Text Full Text PDF PubMed Scopus (469) Google Scholar]PM plication [34Matsui Y. Fukada Y. Naito Y. Sasaki S. Integrated overlapping ventriculoplasty combined with papillary muscle plication for severely dilated heart failure.J Thorac Cardiovasc Surg. 2004; 127: 1221-1223Abstract Full Text Full Text PDF PubMed Scopus (38) Google Scholar]Commissural or central leaflet closure (Alfieri stitch [35Alfieri O. Maisano F. De Bonis M. et al.The double-orifice technique in mitral valve repair: a simple solution for complex problems.J Thorac Cardiovasc Surg. 2001; 122: 674-681Abstract Full Text Full Text PDF PubMed Scopus (656) Google Scholar, 36Lapenna E. De Bonis M. Sorrentino F. et al.Commissural closure for the treatment of commissural mitral valve prolapse or flail.J Heart Valve Dis. 2008; 17: 261-266PubMed Google Scholar])Advancement plasty [37Barlow C.W. Ali Z.A. Lim E. Barlow J.B. Wells F.C. Modified technique for mitral repair without ring annuloplasty.Ann Thorac Surg. 2003; 75: 298-300Abstract Full Text Full Text PDF PubMed Scopus (29) Google Scholar]Chordal transfer [38Smedira N.G. Selman R. Cosgrove D.M. et al.Repair of anterior leaflet prolapse: chordal transfer is superior to chordal shortening.J Thorac Cardiovasc Surg. 1996; 112: 287-292Abstract Full Text Full Text PDF PubMed Scopus (111) Google Scholar]“Hitch” sutures [39Marasco S.F. Rosenfeldt F.L. Lim H.K. et al.Correction of posteromedial papillary muscle displacement in repair of ischemic mitral regurgitation.J Heart Valve Dis. 2008; 17: 620-627PubMed Google Scholar]Leaflet folding plasty [40Grossi E.A. Galloway A.C. Kallenbach K. et al.Early results of posterior leaflet folding plasty for mitral valve reconstruction.Ann Thorac Surg. 1998; 65: 1057-1059Abstract Full Text Full Text PDF PubMed Scopus (45) Google Scholar]Implantation of artificial chords [41Mohr F.W. Onnasch J.F. Falk V. et al.The evolution of minimally invasive valve surgery—2 year experience.Eur J Cardiothorac Surg. 1999; 15: 233-239Crossref PubMed Scopus (131) Google Scholar]PM imbrication [42Menicanti L. Di Donato M. Frigiola A. et al.Ischemic mitral regurgitation: intraventricular papillary muscle imbrication without mitral ring during left ventricular restoration.J Thorac Cardiovasc Surg. 2002; 123: 1041-1050Abstract Full Text Full Text PDF PubMed Scopus (150) Google Scholar]PM = papillary muscle. Open table in a new tab Table 2 illustrates the conclusions of the studies describing sizing and ring size selection strategies using a ring-specific sizer. The opinions on sizing and ring size selection strategies are as strong as they are different. Interestingly, some authors suggest sizing strategies contradicting the manufacturer's recommendations. For instance, several studies suggest the assessment of the intertrigonal distance for evenly labeled rings (eg, Carpentier-Edwards (CE) Physio or CE Classic) or bands (eg, Edwards Cosgrove) although this sizing approach is usually meant for rings with odd numbers (except for the Medtronic 3D Profile or CG Future band/ring, which are evenly labeled but sized to the trigones). It is reasonable to assume that those researchers select a smaller ring than studies using the intercommissural distance. In any case, the methods of ring size selection vary widely among surgeons.Table 2Suggested Annuloplasty Ring Sizing and Ring Selection Strategies Using a SizerFirst Author [Ref]Sizing StrategyRing Size SelectionRing TypeUnderlying PathologyAdams [43Adams D.H. Anyanwu A.C. Rahmanian P.B. et al.Large annuloplasty rings facilitate mitral valve repair in Barlow's disease.Ann Thorac Surg. 2006; 82: 2096-2101Abstract Full Text Full Text PDF PubMed Scopus (111) Google Scholar]IC distance, AML heightAs assessed with sizer, “with bias to choose larger size if between sizes”CE PhysioBarlow'sCarpentier [10Carpentier A. Cardiac valve surgery—the ”French correction.”.J Thorac Cardiovasc Surg. 1983; 86: 323-337PubMed Google Scholar]AML surface areaAs assessed with sizerCE ClassicDNPCarpentier [8Carpentier A.F. Lessana A. Relland J.Y. et al.The “physio-ring”: an advanced concept in mitral valve annuloplasty.Ann Thorac Surg. 1995; 60: 1177-1186Abstract Full Text PDF PubMed Scopus (309) Google Scholar]IC distance, AML heightAs assessed with sizer; if no good correlation between width and height of AML is found, a CE Classic should be taken and bent accordinglyCE PhysioFED (47%), Barlow's (19%), endocarditis (11%), rheumatic (9%), congenital (6%), other (8%)Chen [7Chen F.Y. Cohn L.H. Mitral valve repair.in: Cohn L.H. Edmunds L.H. Cardiac surgery in the adult. 2nd ed. McGraw-Hill, New York2008: 1013-1029Google Scholar]IT distanceAs assessed with sizerDNPRheumaticAML height“Slight oversizing”DNPDegenerativeChung [44Chung C.H. Kim J.B. Choo S.J. et al.Long-term outcomes after mitral ring annuloplasty for degenerative mitral regurgitation: Duran ring versus Carpentier-Edwards ring.J Heart Valve Dis. 2007; 16: 536-545PubMed Google Scholar]IC distance for CE Classic and IT distance for Medtronic DuranAs assessed with sizerCE Classic and Medtronic DuranDegenerativeCook [45Cook R.C. Nifong L.W. Lashley G.G. et al.Echocardiographic measurements alone do not provide accurate non-invasive selection of annuloplasty band size for robotic mitral valve repair.J Heart Valve Dis. 2006; 15: 524-527PubMed Google Scholar]IT distanceIT distance was assessed echocardiographically, a nomogram showing Edwards' sizer notch distances was used to select band sizeEdwards CosgroveFED (45%), Barlow's (37%), rheumatic (9%), other (9%)De Bonis [46De Bonis M. Taramasso M. Grimaldi A. et al.The GeoForm annuloplasty ring for the surgical treatment of functional mitral regurgitation in advanced dilated cardiomyopathy.Eur J Cardiothorac Surg. 2011; 40: 488-495PubMed Google Scholar]IT distanceTwo sizes smaller than measured IT distanceEdwards GeoFormIschemic and dilated cardiomyopathyFilsoufi [47Filsoufi F. Carpentier A. Principles of reconstructive surgery in degenerative mitral valve disease.Semin Thorac Cardiovasc Surg. 2007; 19: 103-110Abstract Full Text Full Text PDF PubMed Scopus (82) Google Scholar]IC distance, AML surface areaAs assessed with sizer; if surgeon hesitates between 2 sizes, select greater sizeDNPDegenerativeGazoni [48Gazoni L.M. Fedoruk L.M. Kern J.A. et al.A simplified approach to degenerative disease: triangular resections of the mitral valve.Ann Thorac Surg. 2007; 83: 1658-1665Abstract Full Text Full Text PDF PubMed Scopus (44) Google Scholar]“Sized to AML” and IT distanceOne size greater than measured“Complete or partial semirigid ring”DegenerativeMaisano [49Maisano F. La Canna G. Grimaldi A. et al.Annular-to-leaflet mismatch and the need for reductive annuloplasty in patients undergoing mitral repair for chronic mitral regurgitation due to mitral valve prolapse.Am J Cardiol. 2007; 99: 1434-1439Abstract Full Text Full Text PDF PubMed Scopus (25) Google Scholar]IC distance, AML surface areaAs assessed with sizerSJM SeguinMitral valve prolapsePerier[50Perier P. Hohenberger W. Lakew F. et al.Toward a new paradigm for the reconstruction of posterior leaflet prolapse: midterm results of the “respect rather than resect” approach.Ann Thorac Surg. 2008; 86: 718-725Abstract Full Text Full Text PDF PubMed Scopus (182) Google Scholar]IT distance, AML surface areaAs assessed with sizerCE Classic, CE PhysioPosterior leaflet prolapseBorghetti [51Borghetti V. Campana M. Scotti C. et al.Biological versus prosthetic ring in mitral-valve repair: enhancement of mitral annulus dynamics and left-ventricular function with pericardial annuloplasty at long term.Eur J Cardiothorac Surg. 2000; 17: 431-439Crossref PubMed Scopus (56) Google Scholar]AML surface areaAs assessed with sizerCE ClassicDegenerative (81%), Barlow's (9.5%), healed endocarditis (9.5%)Chang [52Chang B.C. Youn Y.N. Ha J.W. et al.Long-term clinical results of mitral valvuloplasty using flexible and rigid rings: a prospective and randomized study.J Thorac Cardiovasc Surg. 2007; 133: 995-1003Abstract Full Text Full Text PDF PubMed Scopus (69) Google Scholar]AML size for CE Classic and IT distance for Medtronic DuranAs assessed with sizerCE Classic and Medtronic DuranDegenerative (66%), rheumatic (11%), dilated cardiomyopathy (10%), congenital (7%), other (6%)Dreyfus [53Dreyfus G.D. Souza Neto O. Aubert S. Papillary muscle repositioning for repair of anterior leaflet prolapse caused by chordal elongation.J Thorac Cardiovasc Surg. 2006; 132: 578-584Abstract Full Text Full Text PDF PubMed Scopus (23) Google Scholar]IC distance, AML surface areaAs assessed with sizerCE ClassicBarlow's (36%), “dystrophic disease” (51%), healed endocarditis (4%), rheumatic (4%), ischemic cardiomyopathy (3%), congenital (2%)Fattouch [54Fattouch K. Guccione F. Sampognaro R. et al.POINT. Efficacy of adding mitral valve restrictive annuloplasty to coronary artery bypass grafting in patients with moderate ischemic mitral valve regurgitation: a randomized trial.J Thorac Cardiovasc Surg. 2009; 138: 278-285Abstract Full Text Full Text PDF PubMed Scopus (249) Google Scholar]Measuring height of A2 segment by means of TEE (transesophageal view at 120 degrees)Choose prosthetic ring with anteroposterior diameter of less than 0.8 to 1 cm with respect to height of A2 segmentCE PhysioIschemic cardiomyopathyKshettry [55Kshettry V.R. Kanda L.T. Prospective study of mitral valve repair with the CarboMedics AnnuloFlex annuloplasty system: effectiveness and safety after one year.J Heart Valve Dis. 2005; 14: 105-113PubMed Google Scholar]IC distanceAs assessed with sizerCarbomedics AnnuloflexDegenerative (90%), ischemic cardiomyopathy (4%), other (6%)Lange [56Lange R. Guenther T. Kiefer B. et al.Mitral valve repair with the new semirigid partial Colvin-Galloway Future annuloplasty band.J Thorac Cardiovasc Surg. 2008; 135: 1087-1093Abstract Full Text Full Text PDF PubMed Scopus (14) Google Scholar]AML length, IT distanceAs assessed with sizerMedtronic CG FutureDegenerative (66%), ischemic cardiomyopathy (20%), infectious (7%), other (7%)Rankin [57Rankin J.S. Orozco R.E. Addai T.R. et al.Several new considerations in mitral valve repair.J Heart Valve Dis. 2004; 13: 399-409PubMed Google Scholar]IT distanceAs assessed with sizerCE ClassicMV prolapse (56%), mitral annular dilation (18%), ischemic cardiomyopathy (26%)Braun [18Braun J. Bax J.J. Versteegh M.I. et al.Preoperative left ventricular dimensions predict reverse remodeling following restrictive mitral annuloplasty in ischemic mitral regurgitation.Eur J Cardiothorac Surg. 2005; 27: 847-853Crossref PubMed Scopus (207) Google Scholar, 58Braun J. van de Veire N.R. Klautz R.J. et al.Restrictive mitral annuloplasty cures ischemic mitral regurgitation and heart failure.Ann Thorac Surg. 2008; 85: 430-437Abstract Full Text Full Text PDF PubMed Scopus (254) Google Scholar]IT distance, AML heightDownsized by two sizesCE PhysioIschemic cardiomyopathyDaimon [59Daimon M. Fukuda S. Adams D.H. et al.Mitral valve repair with Carpentier-McCarthy-Adams IMR ETlogix annuloplasty ring for ischemic mitral regurgitation: early echocardiographic results from a multi-center study.Circulation. 2006; 114: I588-I593Crossref PubMed Scopus (110) Google Scholar]IC distance, AML surface areaAs assessed with sizerEdwards IMR ETlogixIschemic cardiomyopathyGeidel [60Geidel S. Lass M. Schneider C. et al.Downsizing of the mitral valve and coronary revascularization in severe ischemic mitral regurgitation results in reverse left ventricular and left atrial remodeling.Eur J Cardiothorac Surg. 2005; 27: 1011-1016Crossref PubMed Scopus (55) Google Scholar, 61Geidel S. Lass M. Krause K. et al.Early and late results of restrictive mitral valve annuloplasty in 121 patients with cardiomyopathy and chronic mitral regurgitation.Thorac Cardiovasc Surg. 2008; 56: 262-268Crossref PubMed Scopus (24) Google Scholar, 62Geidel S. Lass M. Ostermeyer J. Restrictive mitral valve annuloplasty for chronic ischemic mitral regurgitation: a 5-year clinical experience with the physio ring.Heart Surg Forum. 2008; 11: E225-E230Crossref PubMed Scopus (5) Google Scholar]IC distance, AML surface areaLVEF >30%, 20–30%, <20%, downsizing for 2, 3, 4 ring sizes, respectivelyCE Physio, Medtronic Duran, Edwards IMR ETlogixIschemic and dilated cardiomyopathyGelsomino [63Gelsomino S. Lorusso R. Capecchi I. et al.Left ventricular reverse remodeling after undersized mitral ring annuloplasty in patients with ischemic regurgitation.Ann Thorac Surg. 2008; 85: 1319-1330Abstract Full Text Full Text PDF PubMed Scopus (49) Google Scholar]IT distance, AML heightDownsized by 2 sizesCE Classic, CE PhysioIschemic cardiomyopathyAML = anterior mitral leaflet; CE = Carpentier-Edwards; CG = Calvin-Galloway; DNP = data not provided; FED = fibroelastic deficiency; LVEF = left ventricular ejection fraction; IC = intercommissural; IT = intertrigonal; MV = mitral valve; SJM = St. Jude Medical; TEE = transesophageal echocardiography. Open table in a new tab Alain Carpentier, who developed the first commercially available ring (CE Classic) and ring sizers, recommended sizing the CE Classic ring based on the entire surface area of the AML [10Carpentier A. Cardiac valve surgery—the ”French correction.”.J Thorac Cardiovasc Surg. 1983; 86: 323-337PubMed Google Scholar], whereas he recommended sizing the subsequently developed CE Physio ring by measuring the intercommissural distance and the AML height [8Carpentier A.F. Lessana A. Relland J.Y. et al.The “physio-ring”: an advanced concept in mitral valve annuloplasty.Ann Thorac Surg. 1995; 60: 1177-1186Abstract Full Text PDF PubMed Scopus (309) Google Scholar]. If the sizer does not match both dimensions simultaneously, he suggested using a CE Classic ring and bending it accordingly. While this description has had a tremendous impact on cardiac surgery success worldwide, the scientific rationale behind it has not been described. We, therefore, assume that they are experience driven. Other examples for successful but experience-driven ring sizing strategies pertain to disease-specific annuloplasty rings, for example, Edwards GeoForm and ischemic mitral regurgitation (IMR) ETlogix for FMR/IMR and the Edwards Myxo ETlogix for myxomatous mitral valve disease. The GeoForm and the IMR ETlogix rings disproportionately downsize the mitral annulus in the S-L mitral annular dimension. These rings take into account the pathoanatomic and pathophysiologic mechanisms that lead to ischemic MR. Similarly, if the Myxo ETlogix ring is used in patients with myxomatous mitral valve disease, it accounts for the enlarged anterior leaflet by increased S-L dimension and may thereby reduce the risk of systolic anterior leaflet motion. Lastly, adjustable annuloplasty ring types have been introduced recently [11Langer F. Borger M.A. Czesla M. et al.Dynamic annuloplasty for mitral regurgitation.J Thorac Cardiovasc Surg. 2012 Feb 23; ([E-Pub ahead of print])Google Scholar]. This increasing number of alternative ring type choices, however, may increase uncertainty in their application.Sizing Uncertainty Is Further Enhanced by the Option to Insert Annuloplasty BandsAnnuloplasty bands are usually polyester velour covered structures that are attached to the posterior annulus only and anchored in the fibrous trigones [12Cosgrove D.M. Arcidi J.M. Rodriguez L. et al.Initial experience with the Cosgrove-Edwards annuloplasty system.Ann Thorac Surg. 1995; 60: 499-504Abstract Full Text PDF PubMed Scopus (124) Google Scholar]. Owing to their flexibility, they are supposed to respect the three-dimensional structure of the annulus more than complete rigid rings. Several bands are commercially available, with the Edwards Cosgrove band being the most popular today. Cosgrove bands are evenly labeled (ie, sizer notches should indicate C-C sizing) and available in seven different sizes (size 26 to 38, with a size 40 available outside the United States). The total length of these Cosgrove bands ranges from 58 mm (size 26) to 83 mm (size 38).A second commercially available band is the Sorin Sovering Miniband (Sorin-CarboMedics, Austin, TX) endorsed by Calafiore and colleagues [13Calafiore A.M. Di Mauro M. Iaco A.L. et al.Overreduction of the posterior annulus in surgical treatment of degenerative mitral regurgitation.Ann Thorac Surg. 2006; 81: 1310-1316Abstract Full Text Full Text PDF PubMed Scopus (18) Google Scholar]. This band is available in two total lengths, 40 mm and 50 mm. Calafiore and colleagues [13Calafiore A.M. Di Mauro M. Iaco A.L. et al.Overreduction of the posterior annulus in surgical treatment of degenerative mitral regurgitation.Ann Thorac Surg. 2006; 81: 1310-1316Abstract Full Text Full Text PDF PubMed Scopus (18) Google Scholar] state that the size of the ring is chosen according to the height of the AML measured on the transesophageal echocardiogram. If the height is 25 mm or higher, a 50 mm band is used; if lower, a 40 mm band is positioned 13Calafiore A.M. Di Mauro M. Iaco A.L. et al.Overreduction of the posterior annulus in surgical treatment of degenerative mitral regurgitation.Ann Thorac Surg. 2006; 81: 1310-1316Abstract Full Text Full Text PDF PubMed Scopus (18) Google Scholar. The manufacturer's statements on band sizing are not only different from those of Dr Calafiore, but even contradictory between those in the brochure and those on the CTSNet website: in the brochure, it is claimed that ring size 40 is indicated for posterior mitral annuloplasty in insufficient valves caused by dilated or postischemic cardiomyopathy, whereas size 50 is designated for posterior mitral annuloplasty in MR caused by organic diseases of the mitral valve. On the CTSNet website, the band with the 40 mm length is recommended for mitral repair and the 50 mm for tricuspid repair. Furthermore, whereas Calafiore and coworkers [13Calafiore A.M. Di Mauro M. Iaco A.L. et al.Overreduction of the posterior annulus in surgical treatment of degenerative mitral regurgitation.Ann Thorac Surg. 2006; 81: 1310-1316Abstract Full Text Full Text PDF PubMed Scopus (18) Google Scholar] recommend anchoring the band to the trigones, the manufacturer proposes attaching the ends of the band to the commissures.A third commercially available band is the Medtronic Simplici-T, promoted by Tirone David. This band supports the concept that it is unnecessary to determine the size of an annuloplasty band and eliminates the need for conventional sizing. If this band is used, interrupted sutures are first placed around the posterior mitral annulus from trigone to trigone (it is assumed that each bite on the annulus is identical). These sutures are then stitched through the band approximately 4 mm to 5 mm in width and 1 mm to 2 mm apart from the previous suture pair (starting 2 mm from the band end). After the stitches are placed, the 100 mm long band is trimmed as needed. Consequently, the band length depends on the number of sutures placed. In theory, assuming a 4 mm width of each suture, a 2 mm distance between suture pairs and a 2 mm distance to each end, the band will be 74 mm long if 12 sutures are placed or 86 mm long if 14 sutures are placed.Finally, the Mayo Clinic group also argues that it is unnecessary to determine the size of an annuloplasty ring or band. Their approach calls for use of a partial 63 mm flexible band that is anchored to both trigones for all patients, regardless of the etiology of MR [14Suri R.M. Schaff H.V. Dearani J.A. et al.Survival advantage and improved durability of mitral repair for leaflet prolapse subsets in the current era.Ann Thorac Surg. 2006; 82: 819-826Abstract Full Text Full Text PDF PubMed Scopus (343) Google Scholar]. This band is a modified Medtronic Duran C ring, which is only 1 mm longer than a 28 Cosgrove band.Thus, it is clear from the above illustrations that partial band sizing is even more diverse and confusing than ring sizing, and objective evidence is practically absent. Another issue important in this context affecting sizing strategies for both rings and bands is the terminology used in the process of ring or band sizing.True Sizing, Upsizing, and Downsizing: There Is No Common DefinitionMany surgeons use the terms “true sizing,” “down (under) sizing,” or “up (over) sizing” to describe their strategy of ring size selection. Considering the already mentioned three-dimensional shape and the dynamics of the mitral annulus, the difficulty of determining the true size of the annulus for ring or band size selection becomes apparent. Further, we do not operate on normal mitral valves: all the dimensions measured before repairing the valve will reflect various degrees of pathologic change. Most surgeons refer to the dimensions that are intraoperatively assessed using the ring sizer and not to the original mitral annular dimensions. We recently found that implantation of such “true sized” annuloplasty rings in healthy sheep hearts reduces mitral annular dimensions in vivo [15Bothe W. Kvitting J.P. Swanson J.C. et al.Effects of different annuloplasty rings on anterior mitral leaflet dimensions.J Thorac Cardiovasc Surg. 2010; 139: 1114-1122Abstract Full Text Full Text PDF PubMed Scopus (34) Google Scholar]. It is therefore reasonable to assume that almost any ring implantation based on true sizing actually results in downsizing the annulus. This perspective compounds the confusion if one then encounters ring selection policies that vary from true sizing to upsizing by one size in patients with structural disease and downsizing by as many as four sizes in patients with FMR. This perplexity
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