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Surgery in severe mitral regurgitation: focus on patients with no symptoms or complications

An article from the e-journal of the ESC Council for Cardiology Practice

Mitral valve repair is often recommended in severe mitral regurgitation however absence of symptoms and episodes of atrial fibrillation, a preserved left ventricular function and normal pulmonary artery pressure either warrant early repair or watchful waiting depending on 1) the patient's characteristics, 2) surgical risk, 3) likelihood of an effective and durable repair and 4) local expertise. Review in this article the general indications for mitral repair with a focus on the special considerations to observe in these patients, and a review of the early markers of initial MR decompensation.

Valvular Heart Disease


Background

Mitral valve (MV) repair is optimal surgical treatment for severe degenerative mitral regurgitation (MR) (1). The ESC guidelines on valvular heart disease (2012) recommend MV repair in symptomatic severe degenerative MR and in cases of initial signs of left ventricular (LV) dilatation or dysfunction - end-systolic diameter ≥45 mm (2) or ≥40 mm (ACC/AHA 2006 guidelines) - (3) and/or ejection fraction <60% (class I).
Asymptomatic patients with preserved LV function, in presence of atrial fibrillation (AF) and/or pulmonary hypertension (PHT) (SPAP>50 mmHg at rest) (class IIa) as well as pulmonary induced hypertension with exercise (SPAP >60 mmHg) are indicated for MV repair as well (class IIa) (3). Left ventricular dysfunction/dilatation (4-5), PHT (6) and AF (7) are each a predictor of poor outcome under medical management and are triggers to prompt surgery without further delay, even if actual repair is unlikely. 
Patients who are asymptomatic and free from mitral regurgitation however, can be the object of either a "wait and see" (watchful waiting) approach or an "early repair" strategy according to the specific factors that we present in this review.

I - Deciding on valve repair

Asymptomatic patients with severe degenerative MR under the "wait and see" approach receive regular clinical and echocardiographic exams and are sent for surgery as soon as symptoms of LV dilatation/dysfunction, PHT or recurrent AF develop. Rosenhek and co-workers (8) demonstrated that close follow-up (every 3-12 months) in experienced hands with prompt surgical referral offer survival rates that are no significantly different than those yielded from early repair. Other groups nevertheless have challenged the safety of this approach (9-13). Montant demonstrated that the overall outcome of asymptomatic patients with severe degenerative MR is more favorable with an early surgery approach than regular and close (at least once a year) outpatient follow-ups for timely referral.
The rationale behind early repair in these instances is to treat severe MR before pathological changes have occurred thus preserving patients in a state of normal ventricular and atrial chambers, normal rhythm (i.e. no persistent or permanent disturbances) and good long-term valve function, the aim being to ultimately ensure a survival rate and quality of life identical to the matched population. Thus, mitral repair is performed in asymptomatic patients well before the development of symptoms, LV dysfunction, AF or PHT in many referral centers.
Early repair, nevertheless, is to be considered only if the surgical risk is very low and the likelihood of a successful valve repair is very high (greater than 90%) (2,3). Today's excellence centers in reconstructive mitral surgery are able to provide a repair rate above 95% (14-18), a hospital mortality below 1% (19-24) and very satisfactory long-term outcomes (11,20-23,25). In these centers, freedom from reoperation is >90% at 10 years (18,20-22,25,26) and >80 % at 20 years (21,25). Long-term survival and quality of life are rigorously identical to that of the matched general population (13,27). The vast majority of cardiac surgery units however uncommonly offer the possibility of mitral repair to patients with potentially reparable valves. In these units, these potential candidates for repair receive valve replacement instead. 

II - Early markers of initial MR decompensation 

Several silent pathological alterations may occur in patients with severe MR before the occurrence of the classic I or IIa indications for surgery. Even under medical management, the severity of MR itself (28), dilatation of the left atrium (volume index ≥ 60 ml/m²) (29), elevated BNP levels (30), reduced functional capacity (31) and exercise induced pulmonary hypertension (≥60 mm Hg) (32) are associated with significant risk.
Indeed, patients with a left atrial volume index ≥ 60 ml/m2 experience more cardiac events and higher mortality compared to the normal population or patients with MR and lower LA enlargement (29). Similarly, the occurrence of exercise pulmonary hypertension (≥60 mm Hg) is associated with an event-free survival rate of 35%±8% at 2 years compared with 75%±7% for patients without exercise pulmonary hypertension. Reduced functional capacity (<84% than expected) in patients with severe MR who are otherwise completely asymptomatic has also been shown to be associated with a higher rate of cardiac events or need for surgery. High brain natriuretic peptide (BNP) levels in asymptomatic patients with severe MR were shown to be associated with a significantly increased rate of congestive heart failure episodes, LV dysfunction and death (30-32). Those markers, therefore, may help in the risk stratification process of patients and should be considered triggers for earlier surgical valve repair. Interestingly, they do not seem to expose the patients to excess postoperative risk. This means that, as demonstrated for some of them, restoration of life expectancy can be obtained without increased postoperative mortality if surgery is promptly performed (33). 
The European guidelines recommend that early surgery be considered, if the surgical risk is low and the likelihood of a durable repair very high, in case of flail leaflet and LVESD ≥40 mm (IIa) and may be considered in presence of exercise induced SPAP > 60 mmHg and/or severe left atrial dilatation (volume index ≥60 ml/m2 BSA) (IIb). 

Conclusions 

In presence of low surgical risk and high probability of durable repair, early surgery may represent the preferred approach, particularly in advanced repair centers. This strategy can avoid leaving the patient with the irreversible consequences of the adverse changes in cardiac structure and function associated with the complications of MR. 
Furthermore, dilatation of the left atrium (volume index ≥ 60 ml/m²), elevated BNP levels, reduced functional capacity and exercise induced pulmonary hypertension (≥60 mm Hg) are markers that may help in the risk stratification process of patients and should be considered triggers for earlier surgical valve repair. 
Nevertheless, a watchful waiting approach should probably be preferred in case of high surgical risk (elderly patients with relevant comorbidities) and/or low probability of durable repair (complex valve lesions/insufficient surgical expertise). 
Until high-quality valve repair surgery becomes widespread, an early repair strategy cannot be generally adopted and should be limited to the relatively small number of referral centers with proven expertise in mitral repair surgery.

References



1) Mitral valve repair versus replacement. Yun KL, Miller, DC. Cardiol Clin 1991;9:315-327.
2) Guidelines on the management of valvular heart disease (version 2012). 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 et al. Eur Heart J. 2012 Oct;33(19):2451-96
3) 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).American College of Cardiology/American Heart Association Task Force on Practice Guidelines.  Endorsed by the Society of Cardiovascular Anesthesiologists, Society for Cardiovascular Angiography and Interventions, and Society of Thoracic Surgeons. Bonow RO, et al. J Am Coll Cardiol 2008;52:e1-e142.
4) Impact of preoperative symptoms on survival after surgical correction of organic mitral regurgitation. Tribouilloy C, et al. Circulation 1999;99:400-405.
5) Echocardiographic prediction of survival after surgical correction of organic mitral regurgitation. Enriquez-Sarano M, Tajik AJ, Schaff HV, Orszulak TA, Bailey KR, Frye RL. Circulation 1994;90:830-837. 
6) Mitral Regurgitation International DAtabase (MIDA) Investigators. Prognostic and therapeutic implications of pulmonary hypertension complicating degenerative mitral regurgitation due to flail leaflet: a multicenter long-term international study. Barbieri A, et al. Eur Heart J 2011; 32:751-759.
7) Atrial fibrillation complicating the course of degenerative mitral regurgitation: Determinants and long-term outcome. Grigioni F et al. J Am Coll Cardiol 2002;40:84–92.
8) Outcome of watchful waiting in asymptomatic mitral regurgitation. Rosenhek R, et al. Circulation 2006;113:2238-2244.
9) Comparison of early surgery versus conventional treatment in asymptomatic severe mitral regurgitation. Kang DH, et al. Circulation 2009;119:797– 804.
10) Outcomes in mitral regurgitation due to flail leaflets. Grigioni F, et al. J Am Coll Cardiol Img 2008;1:133–141.
11) Quantitative determinants of the outcome of asymptomatic mitral regurgitation. Enriquez-Sarano M, et al. N Engl J Med 2005;352:875– 883.
12) Early surgery in patients with mitral regurgitation due to partial flail leaflet: a long-term outcome study. Ling L, et al. Circulation 1997;96:1819–1825.
13) Long-term survival in asymptomatic patients with severe degenerative mitral regurgitation: a propensity score-based comparison between an early surgical strategy and a conservative treatment approach. Montant P, Chenot F, Robert A, Vancraeynest D, Pasquet A, Gerber B, Noirhomme P, El Khoury G, Vanoverschelde JL. J Thorac Cardiovasc Surg 2009;138:1339-48.
14) Valve repair versus valve replacement for degenerative mitral valve disease. Gillinov AM, Blackstone EH, Nowicki ER, Slisatkorn W, Al-Dossari G, Johnston DR, George KM, Houghtaling PL, Griffin B, Sabik JF 3rd, Svensson LG. J Thorac Cardiovasc Surg 2008;135(4):885-93.
15) Small-incision mitral valve repair: safe, durable, and approaching perfection. Gammie JS, Bartlett ST, Griffith BP. Ann Surg 2009;250(3):409-15.
16) Large annuloplasty rings facilitate mitral valve repair in Barlow's disease. Adams DH, Anyanwu AC, Rahmanian PB, Abascal V, Salzberg SP, Filsoufi F. Ann Thorac Surg 2006;82(6):2096-100.
17) Mitral valve reconstruction in Barlow disease: Long-term echographic results and implications for surgical management. Jouan J, Berrebi A, Chauvaud S, Menasché P, Carpentier A, Fabiani JN. J Thorac Cardiovasc Surg 2012;143(4 Suppl):S17-20.
18) A comparison of outcomes of mitral valve repair for degenerative disease with posterior, anterior, and bileaflet prolapse. David TE, Ivanov J, Armstrong S, Christie D, Rakowski H. J Thorac Cardiovasc Surg 2005;130:1242-9.
19) The double-orifice technique in mitral valve repair: a simple solution for complex problems. Alfieri O, Maisano F, De Bonis M, Stefano PL, Torracca L, Oppizzi M, La Canna G. J Thorac Cardiovasc Surg 2001;122:674-681.
20) Similar long-term results of mitral valve repair for anterior compared with posterior leaflet prolapse. De Bonis M, Lorusso R, Lapenna E, Kassem S, De Cicco G, Torracca L, Maisano F, La Canna G, Alfieri O. J Thorac Cardiovasc Surg 2006;131:364-368. 
21) Four decades of experience with mitral valve repair: analysis of differential indications, technical evolution, and long-term outcome. DiBardino DJ, ElBardissi AW, McClure RS, Razo-Vasquez OA, Kelly NE, Cohn LH. J Thorac Cardiovasc Surg 2010;139:76-83.
22) A 20-year experience with mitral valve repair with artificial chordae in 608 patients. Salvador L, Mirone S, Bianchini R, Regesta T, Patelli F, Minniti G, Masat M, Cavarretta E, Valfrè C. J Thorac Cardiovasc Surg 2008;135:1280-7.
23) Outcomes of mitral valve repair for bileaflet prolapse. Okada Y, Nasu M, Koyama T, Shomura Y, Yuzaki M, Murashita T, Fukunaga N, Konishi Y. J Thorac Cardiovasc Surg 2012;143(4 Suppl):S21-3.
24) Clinical and echocardiographic outcomes after repair of mitral valve bileaflet prolapse due to mixomatous disease. Chan V, Ruel M, Chaudry S, Lambert S, Mesana TG. J Thorac Cardiovasc Surg 2012;143(4 Suppl):S8-11.
25) Very long-term results (more than 20 years) of valve repair with Carpentier’s techniques in nonrheumatic mitral valve insufficiency. Braunberger E, Deloche A, Berrebi A, Abdallah F, Celestin JA, Meimoun P, Chatellier G, Chauvaud S, Fabiani JN, Carpentier A. Circulation 2001;104 (suppl I): I-8-I-11. 
26) Durability of mitral valve repair for degenerative disease. Gillinov AM, Cosgrove DM, Blackstone EH, Diaz R, Arnold JH, Lytle BW, Smedira NG, Sabik JF, McCarthy PM, Loop FD. J Thorac Cardiovasc Surg 1998;111:734-743. 
27) Quality of life after mitral valve repair. Heikkinen J, Biancari F, Satta J, Salmela E, Juvonen T, Lepojärvi M. J Heart Valve Dis 2005;14:722–726.
28) Quantitative determinants of the outcome of asymptomatic mitral regurgitation. Enriquez-Sarano E, Avierinos JF, Messika-Zeitoun D, Detaint D, Capps M, Nkomo V, Scott C, Schaff H, Tajik AJ. N Eng J Med 2005;352:875-883.
29) Impact of left atrial volume on clinical outcome in organic mitral regurgitation. Le Tourneau T, Messika-Zeitoun D, Russo A, Detaint D, Topilsky Y, Mahoney DW, Suri R, Enriquez-Sarano M. J Am Coll Cardiol 2010;56:570-578. 
30) Prospective validation of the prognostic usefulness of brain natriuretic peptide in asymptomatic patients with chronic severe mitral regurgitation. Pizarro R, Bazzino OO, Oberti PF, Falconi M, Achilli F, Arias A, Krauss JG, Cagide AM. J Am Coll Cardiol 2009;54: 1099-1106.
31) Cardiopulmonary exercise testing determination of functional capacity in mitral regurgitation: physiologic and outcome implications. Messika-Zeitoun D, Johnson BD, Nkomo V, Avierinos JF, Allison TG, Scott C, Tajik AJ, Enriquez-Sarano M. J Am Coll Cardiol 2006;47:2521-2527.
32) Exercise pulmonary hypertension in asymptomatic degenerative mitral regurgitation. Magne J, Lancellotti P, Piérard LA. Circulation 2010;122:33-41.
33) Limits to surgery in mitral valve disease. Al-Attar A. The e-journal of Cardiology Practice Vol8 N20.

 

Notes to editor


M. De Bonis1, N. Al-Attar2
1. Department of Cardiac Surgery, San Raffaele University Hospital, Via Olgettina 60, 20132 Milan, Italy
2. Golden Jubilee National Hospital, Agamemnon Street, Clydebank, G81 4DY, UK
Authors’ disclosures: none declared

The content of this article reflects the personal opinion of the author/s and is not necessarily the official position of the European Society of Cardiology.