Secondary mitral regurgitation repair techniques and outcomes: Subannular repair techniques in secondary mitral regurgitation type IIIb

Central MessageStandardized relocation of both papillary muscles in addition to ring annuloplasty to correct SMR type IIIb specifically addresses mitral leaflet tethering, potentially improving long-term durability.See Commentaries on pages 98 and 100. Standardized relocation of both papillary muscles in addition to ring annuloplasty to correct SMR type IIIb specifically addresses mitral leaflet tethering, potentially improving long-term durability. See Commentaries on pages 98 and 100. Feature Editor's Note—Despite decades of experimental and clinical work, secondary mitral regurgitation is still a challenge for cardiac surgeons. The excellent outcomes achieved in the treatment of organic mitral disease are light years away for secondary mitral regurgitation. Treating secondary mitral disease is too often a humbling and frustrating experience for all the parties involved (most importantly the patients). We now know that techniques that were designed to treat valvular problems do not work well when the mechanism of the mitral regurgitation is within the left ventricle, but it is still unclear if mitral valve repair may or may not have a role in this setting. The review by Pausch and colleagues is a nice summary of the current technical options with an eye to the future and will be of great interest to all those interested in treating this challenging and humbling disease. Mario Gaudino, MD, PhD, MSCE Secondary mitral regurgitation (SMR) due to left ventricular (LV) remodeling is a common sequel of chronic heart failure and associated with dismal outcome. In addition to optimal medical therapy (OMT), both surgical mitral valve repair and replacement are therapeutic options for selected patients. Isolated mitral annuloplasty is associated with increased rates of recurrent SMR during long-term follow-up and has not shown any prognostic benefit in comparison with chordal-sparing mitral valve replacement (MVR).1Goldstein D. Moskowitz A.J. Gelijns A.C. Ailawadi G. Parides M.K. Perrault L.P. et al.Two-year outcomes of surgical treatment of severe ischemic mitral regurgitation.N Engl J Med. 2016; 374: 344-353Crossref PubMed Scopus (520) Google Scholar Nevertheless, to avoid prosthesis-related complications (eg, increased perioperative mortality, endocarditis, thromboembolism, etc), additional subannular repair techniques, specifically addressing mitral leaflet tethering, have been developed to improve long-term mitral valve competence. We herein review the current subannular treatment options, with a special emphasis on the technique of standardized papillary muscle relocation (Figure 1) and its potential prognostic benefits in the treatment of SMR type IIIb. According to Alain Carpentier's classification of mitral regurgitation, which is based on mitral leaflet motion, SMR includes 2 different pathophysiologic entities.2Carpentier A. Cardiac valve surgery—the “French correction”..J Thorac Cardiovasc Surg. 1983; 86: 323-337Abstract Full Text PDF PubMed Google Scholar SMR with normal leaflet motion (type I) is mainly caused by isolated mitral annular dilatation due to atrial remodeling and is therefore also referred to as “atrial SMR.”3Deferm S. Bertrand P.B. Verbrugge F.H. Verhaert D. Rega F. Thomas J.D. et al.Atrial functional mitral regurgitation: JACC review topic of the week.J Am Coll Cardiol. 2019; 73: 2465-2476Crossref PubMed Scopus (110) Google Scholar Most notably in patients with long-lasting permanent atrial fibrillation, excessive atrial dilatation and consecutive mitral annular dilatation lead to a central coaptation defect of the mitral leaflets, mostly without LV dysfunction.4Kagiyama N. Mondillo S. Yoshida K. Mandoli G.E. Cameli M. Subtypes of atrial functional mitral regurgitation: imaging insights into their mechanisms and therapeutic implications.JACC Cardiovasc Imaging. 2020; 13: 820-835Crossref PubMed Scopus (42) Google Scholar On the contrary, SMR with restricted leaflet motion during systole (type IIIb) is the result of progressive LV remodeling caused by ischemic or dilated cardiomyopathy (DCM) and is therefore also referred to as “ventricular SMR.” Accompanying chronic heart failure, progressive global LV dilatation as well as regional cardiac remodeling promotes LV geometric distortion. Thereby, the apicolateral displacement of both papillary muscles leads to mitral leaflet tethering (Figure 2) and restrictive leaflet motion during systole.5Asgar A.W. Mack M.J. Stone G.W. Secondary mitral regurgitation in heart failure: pathophysiology, prognosis, and therapeutic considerations.J Am Coll Cardiol. 2015; 65: 1231-1248Crossref PubMed Scopus (256) Google Scholar Consecutively increased LV volume overload further promotes diastolic wall stress, LV dilatation, and worsening of heart failure.6Nasser R. Van Assche L. Vorlat A. Vermeulen T. Van Craenenbroeck E. Conraads V. et al.Evolution of functional mitral regurgitation and prognosis in medically managed heart failure patients with reduced ejection fraction.JACC Heart Fail. 2017; 5: 652-659Crossref PubMed Scopus (66) Google Scholar Furthermore, SMR type IIIb, which is prevalent in about one-third of patients with advanced heart failure,7Varadarajan P. Sharma S. Heywood J.T. Pai R.G. High prevalence of clinically silent severe mitral regurgitation in patients with heart failure: role for echocardiography.J Am Soc Echocardiogr. 2006; 19: 1458-1461Abstract Full Text Full Text PDF PubMed Scopus (29) Google Scholar is associated with excessive mortality, independent of the degree of LV dysfunction.8Goliasch G. Bartko P.E. Pavo N. Neuhold S. Wurm R. Mascherbauer J. et al.Refining the prognostic impact of functional mitral regurgitation in chronic heart failure.Eur Heart J. 2018; 39: 39-46Crossref PubMed Scopus (165) Google Scholar Regarding their differing pathophysiologic background and prognosis,9Okamoto C. Okada A. Nishimura K. Moriuchi K. Amano M. Takahama H. et al.Prognostic comparison of atrial and ventricular functional mitral regurgitation.Open Heart. 2021; 8: e001574Crossref PubMed Scopus (3) Google Scholar surgical therapeutic options for SMR type I and type IIIb should be tailored accordingly. In contrast to pure annular dilatation (SMR type I), the pathogenetic key factors of SMR type IIIb, namely LV distortion and mitral leaflet tethering (Figure 2), are not addressed by isolated mitral annuloplasty. Consequently, isolated mitral annuloplasty, as a treatment option for SMR type IIIb, is associated with significant rates of recurrent SMR (ie, up to 60%) after 1 to 2 years postoperatively1Goldstein D. Moskowitz A.J. Gelijns A.C. Ailawadi G. Parides M.K. Perrault L.P. et al.Two-year outcomes of surgical treatment of severe ischemic mitral regurgitation.N Engl J Med. 2016; 374: 344-353Crossref PubMed Scopus (520) Google Scholar and does not provide any additional benefits in comparison with OMT.10Wu A.H. Aaronson K.D. Bolling S.F. Pagani F.D. Welch K. Koelling T.M. Impact of mitral valve annuloplasty on mortality risk in patients with mitral regurgitation and left ventricular systolic dysfunction.J Am Coll Cardiol. 2005; 45: 381-387Crossref PubMed Scopus (535) Google Scholar Furthermore, although chordal-sparing MVR is associated with an increased perioperative mortality,11Vassileva C.M. Boley T. Markwell S. Hazelrigg S. Meta-analysis of short-term and long-term survival following repair versus replacement for ischemic mitral regurgitation.Eur J Cardiothorac Surg. 2011; 39: 295-303Crossref PubMed Scopus (128) Google Scholar long-term survival after 2 years is similar in comparison to isolated annuloplasty.1Goldstein D. Moskowitz A.J. Gelijns A.C. Ailawadi G. Parides M.K. Perrault L.P. et al.Two-year outcomes of surgical treatment of severe ischemic mitral regurgitation.N Engl J Med. 2016; 374: 344-353Crossref PubMed Scopus (520) Google Scholar Nevertheless, patients without recurrent SMR after isolated annuloplasty showed significantly increased reverse cardiac remodeling in comparison with MVR.1Goldstein D. Moskowitz A.J. Gelijns A.C. Ailawadi G. Parides M.K. Perrault L.P. et al.Two-year outcomes of surgical treatment of severe ischemic mitral regurgitation.N Engl J Med. 2016; 374: 344-353Crossref PubMed Scopus (520) Google Scholar Therefore, in an effort, to improve the long-term durability after mitral valve repair and to avoid the potential drawbacks of MVR, additional subannular repair strategies have been established. Due to the geometric displacement of both papillary muscles, the attached chordae mediate mitral leaflet tethering, thereby disrupting mitral leaflet coaptation. To improve mitral leaflet mobility and resolve leaflet tethering, the division of tethered secondary chordae was designed.12Messas E. Guerrero J.L. Handschumacher M.D. Conrad C. Chow C.M. Sullivan S. et al.Chordal cutting: a new therapeutic approach for ischemic mitral regurgitation.Circulation. 2001; 104: 1958-1963Crossref PubMed Scopus (252) Google Scholar Borger and colleagues13Borger M.A. Murphy P.M. Alam A. Fazel S. Maganti M. Armstrong S. et al.Initial results of the chordal-cutting operation for ischemic mitral regurgitation.J Thorac Cardiovasc Surg. 2007; 133: 1483-1492Abstract Full Text Full Text PDF PubMed Scopus (139) Google Scholar reported their initial results, comparing additional division of secondary chordae with isolated annuloplasty in the treatment of ischemic SMR type IIIb. According to the preoperative echocardiographic determination of the ischemic papillary muscle, the arising tethered secondary chordae were identified intraoperatively and divided in addition to downsizing annuloplasty. Although periprocedural complication rates were similar and a significant reduction of leaflet tethering was demonstrated early postoperatively within the “chordal cutting” group, no additional benefits regarding 2-year survival or event-free-survival were achieved. Nevertheless, Calafiore and coworkers14Calafiore A.M. Refaie R. Iaco A.L. Asif M. Al Shurafa H.S. Al-Amri H. et al.Chordal cutting in ischemic mitral regurgitation: a propensity-matched study.J Thorac Cardiovasc Surg. 2014; 148: 41-46Abstract Full Text Full Text PDF PubMed Scopus (39) Google Scholar demonstrated in a propensity-matched study that additional chordal cutting was associated with reduced rates of recurrent SMR during a follow-up of 33 months in comparison with isolated annuloplasty. Of note, patients with advanced preoperative leaflet tethering (tenting height >10 mm) were excluded and neither long-term survival nor other clinical end points were analyzed. On the contrary, according to Murashita and coworkers,15Murashita T. Okada Y. Kanemitsu H. Fukunaga N. Konishi Y. Nakamura K. et al.Midterm outcomes of chordal cutting in combination with downsized ring annuloplasty for ischemic mitral regurgitation.Ann Thorac Cardiovasc Surg. 2014; 20: 1008-1015Crossref PubMed Scopus (9) Google Scholar long-term recurrence rates of severe SMR were comparably high despite additional chordal cutting in comparison with isolated annuloplasty, especially in patients with excessive preoperative leaflet tethering. Due to the progression of LV distortion and the existence of further sets of chordae, secondary chordal cutting might only temporarily reduce mitral leaflet tethering and not prevent from recurrent SMR in the long run. Furthermore, disturbance of the valvular-ventricular continuity potentially resulting from chordal cutting might even decrease LV function and prevent LV reverse cardiac remodeling.16Rodriguez F. Langer F. Harrington K.B. Tibayan F.A. Zasio M.K. Cheng A. et al.Importance of mitral valve second-order chordae for left ventricular geometry, wall thickening mechanics, and global systolic function.Circulation. 2004; 110: II115-II122PubMed Google Scholar Therefore, despite its simplicity and feasibility, convincing evidence of a beneficial long-term effect of additional chordal cutting to treat of SMR type IIIb in comparison with isolated annuloplasty is still missing. The loss of mitral leaflet mobility and coaptation surface due to mitral leaflet tethering promotes recurrent SMR after isolated annuloplasty.17Hung J. Papakostas L. Tahta S.A. Hardy B.G. Bollen B.A. Duran C.M. et al.Mechanism of recurrent ischemic mitral regurgitation after annuloplasty: continued LV remodeling as a moving target.Circulation. 2004; 110: II85-II90PubMed Google Scholar Therefore, additional leaflet patch augmentation was designed to restore leaflet mobility and increase coaptation surface.18Langer F. Rodriguez F. Cheng A. Ortiz S. Nguyen T.C. Zasio M.K. et al.Posterior mitral leaflet extension: an adjunctive repair option for ischemic mitral regurgitation?.J Thorac Cardiovasc Surg. 2006; 131: 868-877Abstract Full Text Full Text PDF PubMed Scopus (33) Google Scholar According to Kincaid and coworkers,19Kincaid E.H. Riley R.D. Hines M.H. Hammon J.W. Kon N.D. Anterior leaflet augmentation for ischemic mitral regurgitation.Ann Thorac Surg. 2004; 78 (discussion 8): 564-568Abstract Full Text Full Text PDF PubMed Scopus (75) Google Scholar the enlargement of the anterior mitral leaflet using an elliptically shaped 1 × 3-cm bovine pericardial patch in addition to mitral annuloplasty did not increase perioperative risk, whereas the rate of recurrent SMR after 2 years was low. Unfortunately, follow-up was only completed in 60% of the included patients, and the authors did not implement a control group of patients treated with isolated annuloplasty, nor did they give any information about defined inclusion criteria or echocardiographic tethering parameters. de Varennes and coworkers20de Varennes B. Chaturvedi R. Sidhu S. Cote A.V. Shan W.L. Goyer C. et al.Initial results of posterior leaflet extension for severe type IIIb ischemic mitral regurgitation.Circulation. 2009; 119: 2837-2843Crossref PubMed Scopus (77) Google Scholar implanted a bovine pericardial patch, extending from the medial half of P2 to the posterior commissure, in addition to ring annuloplasty. According to their initial results, no periprocedural complications related to leaflet augmentation occurred. Furthermore, promising low rates of recurrent MR after 1 year were achieved, despite absences of LV functional improvement or decrease of LV dimensions. Circumferential augmentation of the posterior mitral leaflet using an autologous pericardial patch was associated with significantly reduced mitral leaflet tethering and an increased coaptation length immediately postoperatively in a single-center observational study with a limited number of patients by Ikeda and coworkers.21Ikeda N. Yamaguchi H. Takagaki M. Mitsuyama S. Ebato M. Tanno K. et al.Extended posterior leaflet augmentation for ischemic mitral regurgitation- augmented posterior leaflet snuggling up to anterior leaflet.Circ J. 2019; 83: 567-575Crossref PubMed Scopus (7) Google Scholar Despite promising periprocedural results, with reduction of leaflet tethering, so far there are no studies available analyzing the long-term effects of additional mitral leaflet patch augmentation in comparison to isolated annuloplasty. Additionally, as there are no studies available addressing the durability of the inserted pericardial patch material, it remains debatable, whether mitral leaflet patch augmentation has any advantage in comparison with chordal-sparing MVR. Although mitral leaflet patch augmentation is feasible, it remains a challenging operation, potentially increasing cardiac bypass and crossclamp times, and is therefore limited to individual cases treated in experienced heart valve centers. As LV distortion including papillary muscle displacement induces mitral leaflet tethering, several subannular repair strategies, focusing on the restoration of LV geometry and papillary muscle orientation, have been introduced.22Harmel E.K. Reichenspurner H. Girdauskas E. in secondary mitral regurgitation: a 2018; 104: PubMed Scopus Google Scholar displacement of both papillary muscles, the muscle during progression of heart K. S. Y. T. T. T. et muscle of functional mitral regurgitation in patients with systolic left ventricular dysfunction.J Thorac Cardiovasc Surg. 2014; 148: Full Text Full Text PDF PubMed Scopus Google Scholar and F. M. C. A. E. C. et muscle versus restrictive annuloplasty for severe ischemic mitral regurgitation.J Am Coll Cardiol. 2016; PubMed Scopus Google Scholar demonstrated within a that using a in addition to ring annuloplasty was associated with a reduction in the rate of recurrent SMR years postoperatively in comparison with isolated annuloplasty. Although there was no regarding long-term additional was associated with an of mitral leaflet tethering and increased LV reverse F. M. C. A. E. C. et muscle versus restrictive annuloplasty for severe ischemic mitral regurgitation.J Am Coll Cardiol. 2016; PubMed Scopus Google Scholar approach by and S. S. Y. T. T. Y. The of papillary muscle mortality and durability of mitral valve repair for ischemic mitral regurgitation.J Cardiothorac Surg. 2014; PubMed Scopus Google Scholar demonstrated a survival benefit of in ischemic SMR type IIIb using a an LV in comparison with an Furthermore, and F. A. S. M. M.H. of papillary muscle in functional mitral regurgitation recurrence in patients with cardiomyopathy and mitral Cardiol. PubMed Google Scholar showed a similar reduction of recurrent SMR after in patients with and consecutive SMR type IIIb. Of note, of was in a mitral valve setting. The of an surgical LV reverse remodeling to resolve mitral leaflet tethering in ischemic SMR type IIIb was by and N. Guerrero J.L. Y. Handschumacher M.D. et of a new surgical approach for ventricular remodeling to ischemic mitral regurgitation: insights from PubMed Scopus Google Scholar experimental study not only of LV distortion and SMR type IIIb but the of papillary muscle in mitral leaflet tethering. Therefore, from relocation of papillary muscles to reduce the in addition to ring annuloplasty was developed to specifically resolve leaflet J.T. relocation of the posterior papillary muscle in chronic ischemic mitral regurgitation.Ann Thorac Surg. Full Text Full Text PDF PubMed Scopus Google Scholar In addition to ring annuloplasty Langer and F. T. K. R. D. et repair technique for ischemic mitral regurgitation with severe leaflet 2009; PubMed Scopus Google Scholar inserted a from the of the papillary muscle and from the LV the continuity the the and left and The is heart with echocardiographic and mitral leaflet tethering is using F. T. K. R. D. et repair technique for ischemic mitral regurgitation with severe leaflet 2009; PubMed Scopus Google Scholar Despite the of mitral leaflet tethering and reduction of recurrent there was no long-term survival benefit in comparison with an control group of patients treated with isolated annuloplasty. Of note, and additional is for the and and K. P. S. G. R. E. et muscle relocation in with valve annuloplasty improve repair results in severe ischemic mitral regurgitation.J Thorac Cardiovasc Surg. Full Text Full Text PDF PubMed Scopus Google Scholar not only a of mitral leaflet tethering and reduced rates of recurrent SMR after additional papillary relocation in comparison with isolated annuloplasty but achieved a reduced rate of cardiac during long-term Of note, all patients bypass and of the patients from To a subannular mitral valve repair results when treating SMR type IIIb, with the advantage of a mitral valve and the of and (Figure J.T. relocation of the posterior papillary muscle in chronic ischemic mitral regurgitation.Ann Thorac Surg. Full Text Full Text PDF PubMed Scopus Google Scholar are the of both papillary muscles (Figure and the posterior mitral valve (Figure ring annuloplasty is both are the posterior of the annuloplasty ring (Figure the LV is with reduction of papillary muscle is achieved on both thereby mitral leaflet tethering and both are on the annuloplasty (Figure E. L. E.K. Reichenspurner H. mitral valve annuloplasty with of both papillary muscles for of IIIb functional mitral 2017; PubMed Google Scholar a significant reduction of echocardiographic of mitral leaflet tethering (tenting height additional papillary muscle relocation was associated with rates of recurrent SMR as well as cardiac 1 year postoperatively in comparison with isolated E. Pausch J. T. J. C. J. et subannular repair outcomes in type IIIb functional mitral regurgitation.Ann Thorac Surg. 2019; Full Text Full Text PDF PubMed Scopus Google Scholar Furthermore, were to of standardized papillary muscle relocation in a mitral valve J. E. C. Reichenspurner H. Girdauskas E. Standardized subannular repair for type IIIb functional mitral regurgitation in a mitral valve J Cardiothorac Surg. 2019; PubMed Scopus Google Scholar which is of interest for patients with ischemic dilated cardiomyopathy without the of or patients with and associated SMR type J. T. L. M. B. Reichenspurner H. et repair for functional mitral regurgitation type IIIb in patients with versus dilated J Cardiothorac Surg. 2021; PubMed Scopus (3) Google Scholar even without of SMR type IIIb papillary muscle relocation might LV reverse remodeling and therefore improve the long-term prognosis of selected heart failure J. T. Reichenspurner H. Girdauskas E. ventricular reverse remodeling after subannular mitral valve repair in heart failure: a Heart J 2020; PubMed Scopus Google Scholar regarding the prognostic effect of repair in patients with heart failure has been G.W. J. S. et repair in patients with heart Engl J Med. 2018; PubMed Scopus Google D. G. B. G. N. et repair or medical treatment for secondary mitral regurgitation.N Engl J Med. 2018; PubMed Scopus Google Scholar the results of the of the for Heart with for the demonstrated that repair of SMR promotes LV reverse and heart failure results of the with the for showed no in comparison with comparison of both studies that patients in the advanced heart failure, severe LV dilatation, and Furthermore, the rate of recurrent SMR 1 year after was within the which to be for long-term D. D. N. E. Thomas C. J. et impact of mitral regurgitation after therapy in functional mitral regurgitation.Eur J Heart Fail. 2020; PubMed Scopus Google Scholar Unfortunately, no information about the mechanism of SMR (type annular dilatation type ventricular was for advanced mitral leaflet tethering (eg, a height >10 mm) the of SMR type IIIb is using to be addressed in future The of patients with heart failure with SMR type IIIb is and to be in a heart cardiac therapy may reverse cardiac remodeling and therefore reduce S. N. L. A. G. M. et left ventricular reverse with cardiac results from the J Heart Fail. 2009; PubMed Scopus Google Scholar Despite on the prognostic benefits of this technique was within current According to the of Heart for the of patients with valvular heart C.M. Nishimura B.A. F. et for the of patients with valvular heart a of the of Heart on clinical 2021; Google Scholar in patients despite with severe do not and ejection and LV systolic should be whereas mitral valve may be C.M. Nishimura B.A. F. et for the of patients with valvular heart a of the of Heart on clinical 2021; Google Scholar Furthermore, only in selected patients with severe SMR are despite and mitral valve during should be Due to increased rates of recurrent MR and evidence of a prognostic benefit after isolated D. Moskowitz A.J. Gelijns A.C. Ailawadi G. Parides M.K. Perrault L.P. et al.Two-year outcomes of surgical treatment of severe ischemic mitral regurgitation.N Engl J Med. 2016; 374: 344-353Crossref PubMed Scopus (520) Google Scholar chordal-sparing mitral valve replacement may be of isolated annuloplasty Of note, additional subannular repair techniques (eg, papillary muscle which are potentially and are so far not within current Furthermore, comparing mitral valve with for treatment of SMR are still missing. SMR includes 2 different pathophysiologic (type I type and therapeutic options should be tailored accordingly. Despite SMR type IIIb has an prognostic impact during the progression of chronic heart failure and to be addressed in selected patients. Isolated ring annuloplasty is associated with increased rates of recurrent has to any additional benefits in comparison with or MVR and should be in the treatment of SMR type IIIb. subannular repair specifically addressing LV geometry and papillary muscle orientation, may improve long-term durability and reverse cardiac remodeling after mitral valve Standardized relocation of both papillary muscles (Figure 1) in addition to ring annuloplasty is in a mitral valve and may improve in comparison with isolated annuloplasty. Although further long-term is it to be a promising therapeutic option for patients with heart failure with associated SMR type IIIb.