Vol. 26 No. 1 (2022)
REVIEWS

Percutaneous mitral edge-to-edge repair

PDF (Русский)
  • E.Z. Golukhova,
  • I.I. Skopin,
  • M.S. Latyshev,
  • I.V. Slivneva
E.Z. Golukhova
A.N. Bakulev National Medical Research Center of Cardiovascular Surgery, Moscow
I.I. Skopin
A.N. Bakulev National Medical Research Center of Cardiovascular Surgery, Moscow
M.S. Latyshev
A.N. Bakulev National Medical Research Center of Cardiovascular Surgery, Moscow
Bio
I.V. Slivneva
A.N. Bakulev National Medical Research Center of Cardiovascular Surgery, Moscow
Этапы имплантации клипса в митральную позицию
DOI: https://doi.org/10.21688/1681-3472-2022-1-9-23

Published 2022-03-31

Keywords

  • Edge-to-Edge repair,
  • MitraClip,
  • mitral insufficiency,
  • mitral valve,
  • percutaneous mitral repair

How to Cite

Golukhova, E., Skopin, I., Latyshev, M., & Slivneva, I. (2022). Percutaneous mitral edge-to-edge repair. Patologiya Krovoobrashcheniya I Kardiokhirurgiya, 26(1), 9–23. https://doi.org/10.21688/1681-3472-2022-1-9-23

Copyright (c) 2022 Golukhova E.Z., Skopin I.I., Latyshev M.S., Slivneva I.V.

Creative Commons License

This work is licensed under a Creative Commons Attribution 4.0 International License.

Abstract

Functional mitral regurgitation, now better known as secondary mitral regurgitation, is the most common acquired heart disease in the world. In most cases, patients with secondary mitral regurgitation have a rather poor prognosis, for example, about 50% of patients are at high risk of surgery or are inoperable, while mortality within 1 year without surgery is 57%. The tactics of treating these patients is the subject of much debate. According to the American Association for Thoracic Surgery (Ischemic Mitral Regurgitation Consensus Guidelines Writing Committee), mitral valve reconstruction is accompanied by a large number of relapses of mitral insufficiency in the long term after surgery, and mitral valve replacement is characterized by high mortality (≥ 13%). With the optimal selected conservative therapy (Guideline-directed medical therapy), in most patients, there is no significant improvement in their condition. Since the 2000s the development of methods of interventional influence on the mitral valve for the treatment of such patients is underway. In the 2010s, interventional treatment techniques began to be widely used, and recommendations for their use began to be developed. In some cases, the results of using the techniques are superior to open surgery. Is it possible to say that the problem of treating patients with functional mitral insufficiency of high operative risk has been solved? In order to answer this question, a literature review was carried out on the interventional treatment of secondary mitral regurgitation using the "edge-to-edge" technique.

We used PICO strategy (Patient, Intervention, Comparison, Outcome) for searching articles. A systematic search for information on the research topic was carried out in the PubMed and Google Scholar databases using search queries, keywords, and logical operators AND, OR. Key words: mitral regurgitation, functional mitral regurgitation, chronic mitral regurgitation, MitraClip, percutaneous mitral repair, mitral insufficiency, mitral valve, Edge-to-Edge repair. In the initial selection, 1,180 publications were received. After analyzing the titles and abstracts, 94 articles were selected, and full-text copies were studied. The final analysis included 43 articles and 2 randomized clinical trials. We have compiled a literature review on the interventional treatment of secondary mitral regurgitation using the "edge-to-edge" technique.

Received 13 July 2021. Revised 4 August 2021. Accepted 9 August 2021.

Funding: The study did not have sponsorship.

Conflict of interest: Authors declare no conflict of interest.

Contribution of the authors: The authors contributed equally to this article.

PDF (Русский)

References

  1. Asgar 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(12):1231-1248. PMID: 25814231. https://doi.org/10.1016/j.jacc.2015.02.009
  2. Baumgartner H., Falk V., Bax J.J., De Bonis M., Hamm C., Holm P.J., Iung B., Lancellotti P., Lansac E., Muñoz D.R., Rosenhek R., Sjögren J., Tornos Mas P., Vahanian A., Walther T., Wendler O., Windecker S., Zamorano J.L., ESC Scientific Document Group. 2017 ESC/EACTS Guidelines for the management of valvular heart disease. Eur Heart J. 2017;38(36):2739-2791. PMID: 28886619. https://doi.org/10.1093/eurheartj/ehx391
  3. Otto C.M., Nishimura R.A., Bonow R.O., Carabello B.A., Erwin J.P. 3rd, Gentile F., Jneid H., Krieger E.V., Mack M., McLeod C., O'Gara P.T., Rigolin V.H., Sundt T.M. 3rd, Thompson A., Toly C. 2020 ACC/AHA Guideline for the management of patients with valvular heart disease: executive summary: a report of the American College of Cardiology/American Heart Association Joint Committee on Clinical Practice Guidelines. Circulation. 2021;143(5):e35-e71. PMID: 33332149. https://doi.org/10.1161/CIR.0000000000000932
  4. Nkomo V.T., Gardin J.M., Skelton T.N., Gottdiener J.S., Scott C.G., Enriquez-Sarano M. Burden of valvular heart diseases: a population-based study. Lancet. 2006;368(9540):1005-1011. PMID: 16980116. https://doi.org/10.1016/S0140-6736(06)69208-8
  5. Здравоохранение в России. 2017: стат. сб. М.: Росстат, 2017. [Healthcare in Russia. 2017: Statistical digest. Moscow; Rosstat Publ., 2017. (In Russ.)]
  6. Coats A.J.S., Anker S.D., Baumbach A., Alfieri O., von Bardeleben R.S., Bauersachs J., Bax J.J., Boveda S., Čelutkienė J., Cleland J.G., Dagres N., Deneke T., Farmakis D., Filippatos G., Hausleiter J., Hindricks G., Jankowska E.A., Lainscak M., Leclercq C., Lund L.H., McDonagh T., Mehra M.R., Metra M., Mewton N., Mueller C., Mullens W., Muneretto C., Obadia J.-F., Ponikowski P., Praz F., Rudolph V., Ruschitzka F., Vahanian A., Windecker S., Zamorano J.L., Edvardsen T., Heidbuchel H., Seferovic P.M., Prendergast B. The management of secondary mitral regurgitation in patients with heart failure: a joint position statement from the Heart Failure Association (HFA), European Association of Cardiovascular Imaging (EACVI), European Heart Rhythm Association (EHRA), and European Association of Percutaneous Cardiovascular Interventions (EAPCI) of the ESC. Eur Heart J. 2021;42(13):1254-1269. PMID: 33734354; PMCID: PMC8014526. https://doi.org/10.1093/eurheartj/ehab086
  7. Mirabel M., Iung B., Baron G., Messika-Zeitoun D., Détaint D., Vanoverschelde J.-L., Butchart E.G., Ravaud P., Vahanian A. What are the characteristics of patients with severe, symptomatic, mitral regurgitation who are denied surgery? Eur Heart J. 2007;28(11):1358-1365. PMID: 17350971. https://doi.org/10.1093/eurheartj/ehm001
  8. Cioffi G., Tarantini L., De Feo S., Pulignano G., Del Sindaco D., Stefenelli C., Di Lenarda A., Opasich C. Functional mitral regurgitation predicts 1-year mortality in elderly patients with systolic chronic heart failure. Eur J Heart Fail. 2005;7(7):1112-1117. PMID: 15919238. https://doi.org/10.1016/j.ejheart.2005.01.016
  9. AATS Ischemic Mitral Regurgitation Consensus Guidelines Writing Committee, Kron I.L., LaPar D.J., Acker M.A., Adams D.H., Ailawadi G., Bolling S.F., Hung J.W., Lim D.S., Mack M.J., O’Gara P.T., Parides M.K., Puskas J.D. 2016 update to The American Association for Thoracic Surgery (AATS) consensus guidelines: Ischemic mitral valve regurgitation. J Thorac Cardiovasc Surg. 2017;153(5):e97-e114. PMID: 28411753. https://doi.org/10.1016/j.jtcvs.2017.01.031
  10. Rossi A., Dini F.L., Faggiano P., Agricola E., Cicoira M., Frattini S., Simioniuc A., Gullace M., Ghio S., Enriquez-Sarano M., Temporelli P.L. Independent prognostic value of functional mitral regurgitation in patients with heart failure. A quantitative analysis of 1256 patients with ischaemic and nonischaemic dilated cardiomyopathy. Heart. 2011;97(20):1675-1680. PMID: 21807656. https://doi.org/10.1136/hrt.2011.225789
  11. Ponikowski P., Voors A.A., Anker S.D., Bueno H., Cleland J.G.F., Coats A.J.S., Falk V., Gonzalez-Juanatey J.R., Harjola V.-P., Jankowska E.A., Jessup M., Linde C., Nihoyannopoulos P., Parissis J.T., Pieske B., Riley J.P., Rosano G.M.C., Ruilope L.M., Ruschitzka F., Rutten F.H., van der Meer P.; ESC Scientific Document Group. 2016 ESC Guidelines for the diagnosis and treatment of acute and chronic heart failure: the Task Force for the diagnosis and treatment of acute and chronic heart failure of the European Society of Cardiology (ESC) Developed with the special contribution of the Heart Failure Association (HFA) of the ESC. Eur Heart J. 2016;37(27):2129-2200. PMID: 27206819. https://doi.org/10.1093/eurheartj/ehw128
  12. Crespo-Leiro M.G., Metra M., Lund L.H., Milicic D., Costanzo M.R., Filippatos G., Gustafsson F., Tsui S., Barge-Caballero E., De Jonge N., Frigerio M., Hamdan R., Hasin T., Hulsmann M., Nalbantgil S., Potena L., Bauersachs J., Gkouziouta A., Ruhparwar A., Ristic A.D., Straburzynska-Migaj E., McDonagh T., Seferovic P., Ruschitzka F. Advanced heart failure: a position statement of the Heart Failure Association of the European Society of Cardiology. Eur J Heart Fail. 2018;20(11):1505-1535. PMID: 29806100. https://doi.org/10.1002/ejhf.1236
  13. Grinberg D., Uhlrich W., Thivolet S., Buzzi R., Rioufol G., Obadia J.F., Pozzi M. The unfinished saga of invasive procedures for secondary mitral regurgitation. Ann Cardiothorac Surg. 2021;10(1):66-74. PMID: 33575177; PMCID: PMC7867419. https://doi.org/10.21037/acs-2020-mv-15
  14. Carpentier A. Cardiac valve surgery – the “French correction”. J Thorac Cardiovasc Surg. 1983;86(3):323-337. PMID: 6887954.
  15. Messika-Zeitoun D., Yiu S.F., Grigioni F., Enriquez-Sarano M. Determinants and prognosis of ischemic mitral regurgitation. Ann Cardiol Angeiol (Paris). 2003;52(2):86-90. PMID: 12754965. https://doi.org/10.1016/s0003-3928(03)00005-2
  16. Alfieri O., Maisano F., De Bonis M., Stefano P.L., Torracca L., Oppizzi M., La Canna G. The double-orifice technique in mitral valve repair: a simple solution for complex problems. J Thorac Cardiovasc Surg. 2001;122(4):674-681. PMID: 11581597. https://doi.org/10.1067/mtc.2001.117277
  17. Alfieri O., De Bonis M., La Canna G., editors. Edge-to-edge mitral repair. From a surgical to a percutaneous approach. Cham: Springer; 2015. https://doi.org/10.1007/978-3-319-19893-4
  18. De Bonis M., Lapenna E., Verzini A., La Canna G., Grimaldi A., Torracca L., Maisano F., Alfieri O. Recurrence of mitral regurgitation parallels the absence of left ventricular reverse remodeling after mitral repair in advanced dilated cardiomyopathy. Ann Thorac Surg. 2008;85(3):932-939. PMID: 18291174. https://doi.org/10.1016/j.athoracsur.2007.11.021
  19. Hung J., Papakostas L., Tahta S.A., Hardy B.G., Bollen B.A., Duran C.M., Levine R.A. Mechanism of recurrent ischemic mitral regurgitation after annuloplasty: continued LV remodeling as a moving target. Circulation. 2004;110(11 Suppl 1):II85-II90. PMID: 15364844. https://doi.org/10.1161/01.CIR.0000138192.65015.45
  20. Скопин И.И., Кахкцян П.В., Мироненко В.А., Машина Т.В., Грошева Т.В. Результаты безимплантационной вальвулопластики митральной недостаточности в сроки до трех лет. Бюллетень НЦССХ им. А.Н. Бакулева РАМН. Сердечно-сосудистые заболевания. 2001;2(3):28. [Skopin I.I., Kahtsyan P.V., Mironenko V.A., Mashina T.V., Grosheva T.V. Results of unimplantation valvuloplasty of mitral regurgitation up to 3 years. The Bulletin of Bakoulev Center. Cardiovascular Diseases. 2001;2(3):28. (In Russ.)]
  21. Bhudia S.K., McCarthy P.M., Smedira N.G., Lam B.-K., Rajeswaran J., Blackstone E.H. Edge-to-edge (Alfieri) mitral repair: results in diverse clinical settings. Ann Thorac Surg. 2004;77(5):1598-1606. PMID: 15111150. https://doi.org/10.1016/j.athoracsur.2003.09.090
  22. Stone G.W., Lindenfeld J., Abraham W.T., Kar S., Lim D.S., Mishell J.M., Whisenant B., Grayburn P.A., Rinaldi M., Kapadia S.R., Rajagopal V., Sarembock I.J., Brieke A., Marx S.O., Cohen D.J., Weissman N.J., Mack M.J., COAPT Investigators. Transcatheter mitral-valve repair in patients with heart failure. N Engl J Med. 2018;379(24):2307-2318. PMID: 30280640. https://doi.org/10.1056/NEJMoa1806640
  23. Praz F., Spargias K., Chrissoheris M., Bullesfeld L., Nickenig G., Deuschl F., Schueler R., Fam N.P., Moss R., Makar M., Boone R., Edwards J., Moschovitis A., Kar S., Webb J., Schäfer U., Feldman T., Windecker S. Compassionate use of the PASCAL transcatheter mitral valve repair system for patients with severe mitral regurgitation: a multicentre, prospective, observational, first-in-man study. Lancet. 2017;390(10096):773-780. PMID: 28831993. https://doi.org/10.1016/S0140-6736(17)31600-8
  24. Lim D.S., Kar S., Spargias K., Kipperman R.M., O’Neill W.W., Ng M.K.C., Fam N.P., Walters D.L., Webb J.G., Smith R.L., Rinaldi M.J., Latib A., Cohen G.N., Schäfer U., Marcoff L., Vandrangi P., Verta P., Feldman T.E. Transcatheter valve repair for patients with mitral regurgitation: 30-day results of the CLASP study. JACC Cardiovasc Interv. 2019;12(14):1369-1378. PMID: 31255562. https://doi.org/10.1016/j.jcin.2019.04.034
  25. Obadia J.-F., Messika-Zeitoun D., Leurent G., Iung B., Bonnet G., Piriou N., Lefèvre T., Piot C., Rouleau F., Carrié D., Nejjari M., Ohlmann P., Leclercq F., Saint Etienne C., Teiger E., Leroux L., Karam N., Michel N., Gilard M., Donal E., Trochu J.-N., Cormier B., Armoiry X., Boutitie F., Maucort-Boulch D., Barnel C., Samson G., Guerin P., Vahanian A., Mewton N., MITRA-FR Investigators. Percutaneous repair or medical treatment for secondary mitral regurgitation. N Engl J Med. 2018;379(24):2297-2306. PMID: 30145927. https://doi.org/10.1056/NEJMoa1805374
  26. Feldman T., Kar S., Rinaldi M., Fail P., Hermiller J., Smalling R., Whitlow P.L., Gray W., Low R., Herrmann H.C., Lim S., Foster E., Glower D., EVEREST Investigators. Percutaneous mitral repair with the MitraClip system: safety and midterm durability in the initial EVEREST (Endovascular Valve Edge-to-Edge REpair Study) cohort. J Am Coll Cardiol. 2009;54(8):686-694. PMID: 19679246. https://doi.org/10.1016/j.jacc.2009.03.077
  27. Feldman T., Kar S., Elmariah S., Smart S.C., Trento A., Siegel R.J., Apruzzese P., Fail P., Rinaldi M.J., Smalling R.W., Hermiller J.B., Heimansohn D., Gray W.A., Grayburn P.A., Mack M.J., Lim D.S., Ailawadi G., Herrmann H.C., Acker M.A., Silvestry F.E., Foster E., Wang A., Glower D.D., Mauri L., EVEREST II Investigators. Randomized comparison of percutaneous repair and surgery for mitral regurgitation: 5-year results of EVEREST II. J Am Coll Cardiol. 2015;66(25):2844-2854. PMID: 26718672. https://doi.org/10.1016/j.jacc.2015.10.018
  28. Glower D.D., Kar S., Trento A., Lim D.S., Bajwa T., Quesada R., Whitlow P.L., Rinaldi M.J., Grayburn P., Mack M.J., Mauri L., McCarthy P.M., Feldman T. Percutaneous mitral valve repair for mitral regurgitation in high-risk patients: results of the EVEREST II study. J Am Coll Cardiol. 2014;64(2):172-181. PMID: 25011722. https://doi.org/10.1016/j.jacc.2013.12.062
  29. Iung B., Armoiry X., Vahanian A., Boutitie F., Mewton N., Trochu J.-N., Lefèvre T., Messika-Zeitoun D., Guerin P., Cormier B., Brochet E., Thibault H., Himbert D., Thivolet S., Leurent G., Bonnet G., Donal E., Piriou N., Piot C., Habib G., Rouleau F., Carrié D., Nejjari M., Ohlmann P., Saint Etienne C., Leroux L., Gilard M., Samson G., Rioufol G., Maucort-Boulch D., Obadia J.F., MITRA-FR Investigators. Percutaneous repair or medical treatment for secondary mitral regurgitation: outcomes at 2 years. Eur J Heart Fail. 2019;21(12):1619-1627. PMID: 31476260. https://doi.org/10.1002/ejhf.1616
  30. Pibarot P., Delgado V., Bax J.J. MITRA-FR vs. COAPT: lessons from two trials with diametrically opposed results. Eur Heart J Cardiovasc Imaging. 2019;20(6):620-624. PMID: 31115470. PMCID: PMC6529908. https://doi.org/10.1093/ehjci/jez073
  31. Braun J., Bax J.J., Versteegh M.I.M., Voigt P.G., Holman E.R., Klautz R.J.M., Boersma E., Dion R.A.E. Preoperative left ventricular dimensions predict reverse remodeling following restrictive mitral annuloplasty in ischemic mitral regurgitation. Eur J Cardiothorac Surg. 2005;27(5):847-853. PMID: 15848325. https://doi.org/10.1016/j.ejcts.2004.12.031
  32. Braun J., van de Veire N.R., Klautz R.J.M., Versteegh M.I.M., Holman E.R., Westenberg J.J.M., Boersma E., van der Wall E.E., Bax J.J., Dion R.A.E. Restrictive mitral annuloplasty cures ischemic mitral regurgitation and heart failure. Ann Thorac Surg. 2008;85(2):430-436; discussion 436-437. PMID: 18222238. https://doi.org/10.1016/j.athoracsur.2007.08.040
  33. Joint Task Force on the Management of Valvular Heart Disease of the European Society of Cardiology (ESC); European Association for Cardio-Thoracic Surgery (EACTS); Vahanian A., Alfieri O., Andreotti F., Antunes M.J., Barón-Esquivias G., Baumgartner H., Borger M.A., Carrel T.P., De Bonis M., Evangelista A., Falk V., Iung B., Lancellotti P., Pierard L., Price S., Schäfers H.-J., Schuler G., Stepinska J., Swedberg K., Takkenberg J., Von Oppell U.O., Windecker S., Zamorano J.L., Zembala M. Guidelines on the management of valvular heart disease (version 2012). Eur Heart J. 2012;33(19):2451-2496. PMID: 22922415. https://doi.org/10.1093/eurheartj/ehs109
  34. Bonow R.O., Carabello B.A., Chatterjee K., de Leon A.C. Jr., Faxon D.P., Freed M.D., Gaasch W.H., Lytle B.W., Nishimura R.A., O'Gara P.T., O'Rourke R.A., Otto C.M., Shah P.M., Shanewise J.S., American College of Cardiology/American Heart Association Task Force on Practice Guidelines. 2008 focused update incorporated into the ACC/AHA 2006 Guidelines for the management of patients with valvular heart disease: a report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines (Writing Committee to revise the 1998 guidelines for the management of patients with valvular heart disease). Endorsed by the Society of Cardiovascular Anesthesiologists, Society for Cardiovascular Angiography and Interventions, and Society of Thoracic Surgeons. J Am Coll Cardiol. 2008;52(13):e1-e142. PMID: 18848134. https://doi.org/10.1016/j.jacc.2008.05.007
  35. Nickenig G., Estevez-Loureiro R., Franzen O., Tamburino C., Vanderheyden M., Lüscher T.F., Moat N., Price S., Dall'Ara G., Winter R., Corti R., Grasso C., Snow T.M., Jeger R., Blankenberg S., Settergren M., Tiroch K., Balzer J., Petronio A.S., Büttner H.-J., Ettori F., Sievert H., Fiorino M.G., Claeys M., Ussia G.P., Baumgartner H., Scandura S., Alamgir F., Keshavarzi F., Colombo A., Maisano F., Ebelt H., Aruta P., Lubos E., Plicht B., Schueler R., Pighi M., Di Mario C., Transcatheter Valve Treatment Sentinel Registry Investigators of the EURObservational Research Programme of the European Society of Cardiology. Percutaneous mitral valve edge-to-edge repair: in-hospital results and 1-year follow-up of 628 patients of the 2011–2012 Pilot European Sentinel Registry. J Am Coll Cardiol. 2014;64(9):875-884. PMID: 25169171. https://doi.org/10.1016/j.jacc.2014.06.1166
  36. Maisano F., Franzen O., Baldus S., Schäfer U., Hausleiter J., Butter C., Ussia G.P., Sievert H., Richardt G., Widder J.D., Moccetti T., Schillinger W. Percutaneous mitral valve interventions in the real world: early and 1-year results from the ACCESS-EU, a prospective, multicenter, nonrandomized post-approval study of the MitraClip therapy in Europe. J Am Coll Cardiol. 2013;62(12):1052-1061. PMID: 23747789. https://doi.org/10.1016/j.jacc.2013.02.094
  37. Adamo M., Godino C., Giannini C., Scotti A., Liga R., Curello S., Fiorina C., Chiari E., Chizzola G., Abbenante A., Visco E., Branca L., Fiorelli F., Agricola E., Stella S., Lombardi C., Colombo A., Petronio A.S., Metra M., Ettori F. Left ventricular reverse remodelling predicts long-term outcomes in patients with functional mitral regurgitation undergoing MitraClip therapy: results from a multicentre registry. Eur J Heart Fail. 2019;21(2):196-204. PMID: 30549159. https://doi.org/10.1002/ejhf.1343
  38. Geis N.A., Puls M., Lubos E., Zuern C.S., Franke J., Schueler R., von Bardeleben R.S., Boekstegers P., Ouarrak T., Zahn R., Ince H., Senges J., Katus H.A., Bekeredjian R. Safety and efficacy of MitraClipTM therapy in patients with severely impaired left ventricular ejection fraction: results from the German transcatheter mitral valve interventions (TRAMI) registry. Eur J Heart Fail. 2018;20(3):598-608. PMID: 28834079. https://doi.org/10.1002/ejhf.910
  39. Neuss M., Schau T., Schoepp M., Seifert M., Holschermann F., Meyhofer J., Butter C. Patient selection criteria and midterm clinical outcome for MitraClip therapy in patients with severe mitral regurgitation and severe congestive heart failure. Eur J Heart Fail. 2013;15(7):786-795. PMID: 23325017. https://doi.org/10.1093/eurjhf/hfs214
  40. Swaans M.J., Bakker A.L.M., Alipour A., Post M.C., Kelder J.C., de Kroon T.L., Eefting F.D., Rensing B.J.W.M., Van der Heyden J.A.S. Survival of transcatheter mitral valve repair compared with surgical and conservative treatment in high-surgical-risk patients. JACC Cardiovasc Interv. 2014;7(8):875-881. PMID: 25147032. https://doi.org/10.1016/j.jcin.2014.01.171
  41. Velazquez E.J., Samad Z., Al-Khalidi H.R., Sangli C., Grayburn P.A., Massaro J.M., Stevens S.R., Feldman T.E., Krucoff M.W. The MitraClip and survival in patients with mitral regurgitation at high risk for surgery: a propensity-matched comparison. Am Heart J. 2015;170(5):1050-1059.e3. PMID: 26542516. https://doi.org/10.1016/j.ahj.2015.08.004
  42. Giannini C., Fiorelli F., De Carlo M., Guarracino F., Faggioni M., Giordano P., Spontoni P., Pieroni A., Petronio A.S. Comparison of percutaneous mitral valve repair versus conservative treatment in severe functional mitral regurgitation. Am J Cardiol. 2016;117(2):271-277. PMID: 26651454. https://doi.org/10.1016/j.amjcard.2015.10.044