**6. Management of patients with persistent significant functional mitral regurgitation after the use of CRT**

Therapeutic targets in patients with functional MR include attenuation of symptoms, lesser number of heart failure hospitalizations, better quality of life and, potentially, survival. At present, the most effective therapies of functional MR are aimed at the underlying LV dysfunction. Therefore, as the first step, optimal medical therapy according to the guidelines for the management of heart failure should be used [36]. As the second step, whenever appropriate, CRT should be implemented in line with the respective guidelines [35, 36]. In patients who remain symptomatic despite optimal medical therapy and CRT (if indicated), mitral valve intervention (surgical or transcatheter repair) should be considered; however, there is no evidence that a reduction of functional MR improves survival [13]. Moreover, the surgery has never clearly been demonstrated to alter the natural history of the primary disease (dilated cardiomyopathy) [85]. Limited empirical data contribute to a lower level of evidence for management recommendations, highlighting the importance of decisions made by the Heart Team. The multidisciplinary Heart Team consisting of imaging experts, heart failure and electrophysiology specialists, interventional cardiologists, and cardiac surgeons should try to reach a consensus on appropriate care. Not only the feasibility of the procedure but also comorbidities, the level of surgical risk, and surgeon experience should be considered [13]. In patients undergoing revascularization, the evaluation and decision to treat (or not to treat) ischemic MR should be made prior to surgery. There is an overall agreement that severe functional MR should be addressed at the time of coronary artery bypass grafting (CABG). The management of moderate functional MR in patients undergoing CABG still raises controversies [86]. The thresholds of functional MR severity are also a matter of debate (as stated earlier). Surgical options in patients with functional MR include mitral valve repair and replacement.


are unclear and thus, resynchronization therapy remains a valuable option in eligible patients. Indications for such treatment should be considered as early as possible, before the development of a severe left ventricular dilatation, a predictor of failure in resynchronization therapy.

Cardiac Dyssynchrony as a Pathophysiologic Factor of Functional Mitral Regurgitation: Role…

http://dx.doi.org/10.5772/intechopen.76605

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**Acronyms and abbreviations**

HF heart failure

LV left ventricle

**Author details**

Barbara Brzezińska<sup>1</sup>

**References**

10.1161/01.CIR.96.3.827

CABG coronary artery bypass grafting

EROA effective regurgitant orifice area

LVEF left ventricular ejection fraction

NYHA New York Heart Association

PISA proximal isovelocity surface area

\*Address all correspondence to: be.brzezinska@gmail.com

\* and Krystyna Łoboz-Grudzień1,2

[1] Lamas GA, Mitchell GF, Flaker GC, Smith SC Jr, Gersh BJ, Basta L, Moye L, Braunwald E, Pfeffer MA, Survival and Ventricular Enlargement Investigators. Clinical significance of mitral regurgitation after acute myocardial infarction. Circulation. 1997;**96**:827-833. DOI:

[2] Grigioni F, Enriquez-Sarano M, Zehr KJ, Bailey KR, Tajik AJ. Ischemic mitral regurgitation: Long-term outcome and prognostic implications with quantitative Doppler assess-

ment. Circulation. 2001;**103**:1759-1764. DOI: 10.1161/01.CIR.103.13.1759

1 Department of Cardiology, T. Marciniak Hospital, Wroclaw, Poland

2 Faculty of Health Science, Wroclaw Medical University, Poland

LBBB left bundle branch block

MR mitral regurgitation

CRT cardiac resynchronization therapy

**Table 2.** Unfavorable TTE characteristics for mitral valve repair in secondary MR [88].

Mechanical LV-assisted devices and heart transplantation should be considered in the most advanced stage of heart failure.

The controversies regarding an optimal surgical approach should be emphasized [87]. After surgical annuloplasty (undersized complete ring to restore leaflet coaptation), residual or recurrent functional MR is frequently observed (in approximately one-third of the cases) [88]. Valve-sparing mitral valve replacement techniques (leaving the leaflet and subvalvular apparatus intact to preserve the LV function) should be considered in patients with echocardiographic predictors of repair failure (**Table 2**) [88]. The surgery should also be considered in heart failure patients with severe functional MR and LVEF <30% but with an option for CABG and the evidence of myocardial viability. Qualification for surgical treatment of functional MR should be restrained if concomitant revascularization is not indicated [89].

Percutaneous edge-to-edge repair (MitraClip device) for FMR is a low-risk procedure and may be considered in patients during high surgical risk, whenever feasible [90]. The treatment may attenuate symptoms, improve quality of life and promote LV reverse remodeling but is inferior to surgical methods in terms of functional MR reduction. Valve intervention is generally contraindicated in patients with LVEF < 15% [13]. Two investigational extracardiac devices, CorCap (Acorn Cardiovascular) [91] and Coapsys (Myocor, Inc., Maple Grove, Minnesota) [92], which have been used to reshape the LV and thus to reduce the degree of functional MR, remained an interesting experiment. In cases of more advanced LV dysfunction (LVEF ≤ 30%) with no option for CABG, the Heart Team should choose between a palliative treatment of functional MR (surgical or transcatheter procedures, ventricular assist devices, heart transplantation) and a conservative therapy, after careful individual appraisal of the patient [13].
