ACC Expert Consensus Decision Pathway on the Management of Mitral Regurgitation: A Review of the 2017 Document for the Cardiac Anesthesiologist

Accepted Manuscript

ACC Expert Consensus Decision Pathway on the Management of Mitral Regurgitation: A Review of the 2017 Document for the Cardiac Anesthesiologist Pankaj Jain MD , Michael Fabbro II, DO PII: DOI: Reference:

S1053-0770(18)30530-5 10.1053/j.jvca.2018.07.029 YJCAN 4807

To appear in:

Journal of Cardiothoracic and Vascular Anesthesia

Received date:

20 January 2018

Please cite this article as: Pankaj Jain MD , Michael Fabbro II, DO , ACC Expert Consensus Decision Pathway on the Management of Mitral Regurgitation: A Review of the 2017 Document for the Cardiac Anesthesiologist, Journal of Cardiothoracic and Vascular Anesthesia (2018), doi: 10.1053/j.jvca.2018.07.029

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TITLE ACC Expert Consensus Decision Pathway on the Management of Mitral Regurgitation: A Review of the

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2017 Document for the Cardiac Anesthesiologist

Corresponding Author Pankaj Jain, MD Assistant Professor of Clinical Anesthesiology

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University of Miami, Miller School of Medicine

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AUTHORS

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Corresponding Address: 1611 NW 12th Ave., Miami, FL 33136.

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Email: [email protected]

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Author

Michael Fabbro II, DO

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Assistant Professor of Clinical Anesthesiology University of Miami, Miller School of Medicine

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ABSTRACT Chronic mitral regurgitation (MR) is the most prevalent valvular lesion in the adult US population. Appropriate patient selection for mitral intervention, as well as selection of the appropriate

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interventional strategy and optimal peri-procedural management rely on thorough clinical evaluation, accurate echocardiographic input and in-depth understanding of chronic MR pathophysiology on part of the cardiac anesthesiologist. While the recently published Expert Consensus Decision Pathway (ECDP) on the management of MR was designed to provide tools to

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help the clinician with broad clinical decision-making including patient referral, this review focuses and elaborates on the key aspects relevant to the cardiac anesthesiologist in the peri-interventional

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setting.

INTRODUCTION

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Chronic mitral regurgitation (MR) is the most prevalent valvular lesion in the adult US population. 1 With expanded indications for mitral valve (MV) repair, and with the advent of novel transcatheter therapies, a

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multidisciplinary approach is central to optimal patient care.2 Cardiac anesthesiologists, in their role as

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peri-interventional physicians and echocardiographic imaging experts, are recognized members of the expanded heart valve team.2 Indeed, the varying etiology, complex mechanisms and the dynamicity of

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chronic MR under anesthesia make accurate echocardiographic input by the cardiac anesthesiologist vital for appropriate selection, guidance and evaluation of mitral interventions. The progression of the underlying disease process of chronic MR has anesthetic and prognostic implications, making it essential for the cardiac anesthesiologist to possess a strong understanding of its pathophysiology and corresponding clinical manifestations. In light of the rapidly changing landscape of chronic MR evaluation and management, it is imperative to stay current with the expanding knowledge related to this. 2

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Based on the 2014 AHA/ACC Guidelines for the Management of Patients with Valvular Heart Disease, as well as its 2017 focused update,2,3 the American College of Cardiology (ACC) developed the 2017 Expert Consensus Decision Pathway (ECDP) for the management of mitral regurgitation. 4 Additional available literature through March of 2017 and expert consensus were taken into account. The stated

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purpose of this ECDP is to complement the available guidelines while bridging their gaps, and to provide templates, algorithms and checklists that can be readily incorporated into clinical practice.

While the ECDP provides broad guidance to clinicians involved in the care of chronic MR patients, this narrative review highlights the key features of the ECDP and further elaborates upon concepts relevant to

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the cardiac anesthesiologist managing these patients in the peri-interventional setting.

OVERVIEW

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The ECDP highlights the following aspects of evaluation and management of patients with chronic MR: 1) clinical assessment with identification of MR signs and symptoms, 2) defining the etiology and

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mechanism of MR, 3) assessment of the severity of MR, 4) treatment of MR, including surgical and

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transcatheter therapies, and 5) considerations for referral to an appropriate tertiary care center or heart valve center for management options including mitral valve intervention. Cardiac anesthesiologists, who

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often manage chronic MR patients presenting for mitral intervention, are actively involved in a majority of these aspects of care, and may participate in multidisciplinary discussions surrounding these issues. We

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shall expand on these aspects of care from the anesthesiologist‘s perspective in the peri- interventional context.

Pre-interventional clinical assessment of MR Although most patients with chronic MR undergoing elective surgical or transcatheter intervention are likely to have undergone prior thorough evaluation, some may present with sub-optimal or inadequate

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assessment. Patients with severe MR may also present for non-cardiac surgery in the absence of recent or adequate cardiac testing. In these situations, the clinical assessment often provides important clues to the underlying pathophysiology as well as disease severity and progression, with important anesthetic implications. Clinical assessment may also play a role in early pre-interventional multidisciplinary

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discussions regarding appropriate management and optimization. Patients are often asymptomatic early in the disease process of chronic MR. The enlarged left ventricle (LV) and left atrium (LA), with enhanced compliance, may accommodate gradually progressive regurgitant volumes, accounting for the initial lack of symptoms. In these patients, exercise testing or the

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6-minute walk test may elicit symptoms. Initial manifestations of chronic MR may include decreased functional capacity and fatigue due to decreased forward flow. Although LV ejection fraction (LVEF) during initial stages may be supranormal to normal, progressive increase in LV wall stress results in eccentric hypertrophy, myocardial dysfunction and subsequent decompensation.5,6 Dyspnea at rest may

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reflect progression of disease to LV dysfunction, LA hypertension and pulmonary congestion, and should alert the cardiac anesthesiologist to the possibility of pulmonary hypertension (PH) and right ventricular

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(RV) dysfunction. Patients may experience palpitations due to underlying atrial fibrillation (AF), the presence of which may indicate the need for surgery in severe MR.2 While the presence of a holosystolic

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murmur is suggestive of MR, the appearance of a third heart sound (S3) and a diastolic murmur is more

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indicative of severity.6 Since S3 could be attributed to congestive heart failure (CHF) regardless of MR, the interpretation of severity based on this finding alone may be difficult in the presence of LV

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dysfunction.

The presence of clinical findings that reflect severe MR, overt LV dysfunction, or PH and RV dysfunction have several important anesthetic implications. Firstly, pre- interventional optimization may be necessary in patients with evidence of decompensation. Additionally, symptomatic patients may benefit from periinterventional inotropic support, as well as invasive hemodynamic monitoring including pulmonary artery catheter (PAC) placement to guide perioperative fluid management and cardiovascular pharmacological 4

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support. Overt pre-operative LV dysfunction, pulmonary hypertension and atrial fibrillation also predict postoperative LV dysfunction,7 thereby affecting patient prognosis. The 2014 AHA/ACC guidelines emphasize the classification of patients into disease stages based on the degree of MR and symptomatology.2 Stage A describes patients as being at risk for developing MR. Stage

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B indicates the presence of mild or moderate MR and implies progression of MR. Stage C includes asymptomatic patients with severe MR, with (C1) or without (C2) LV dysfunction. Stage D indicates the presence of severe symptomatic MR. This staging scheme guides management of disease including intervention and investigational follow-up, with the goal of halting progression, preventing complications,

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and prolonging survival. This scheme also serves as a common language during multidisciplinary discussions, and aids in identification of patients in need mitral intervention. As such, the disease stage may serve as an important consideration for the cardiac anesthesiologist while determining the need for intervention. Broadly speaking, patients with Stage A or B disease are likely to benefit from guideline

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directed medical treatment, whereas Stage C and D patients are candidates for surgery or transcatheter

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intervention.

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Perioperative echocardiography for evaluation of MR

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Echocardiography is invaluable in defining the mechanism, etiology and severity of MR. These variables in turn serve as key components in peri-interventional decision-making. Echocardiography is an

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AHA/ACC class I recommendation for initial evaluation in both primary and secondary MR.2 Usually, transthoracic echocardiography (TTE) is utilized for initial characterization of MR. TTE also establishes baseline LV and RV size and function, LA size and pulmonary hypertension. Transesophageal echocardiography (TEE) is useful when TTE images are suboptimal, due to superior imaging quality. 8 TEE is also preferable in situations where TTE provides inadequate information on the severity or mechanism of MR, or on the status of LV function. 5

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Intraoperative TEE, most often performed by the cardiac anesthesiologist, is considered a standard modality for evaluating the anatomy of the mitral valve, and determining suitability for repair. 2 TEE helps in assessment of adequacy of repair, cardiac function, and need for further intervention in the immediate post repair period.9 In cases of mitral valve replacement, TEE is very useful for identifying

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prosthetic valve dysfunction.10 Given the pivotal role that echocardiography plays in characterization of MR and subsequent management decisions, it is vital that the cardiac anesthesiologist possess a thorough understanding of the mechanism and etiology of chronic MR. It is equally important to be aware of the limitations of individual echocardiographic parameters for reliable MR grading, as severity assessment

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has several pitfalls especially under anesthesia. Furthermore, use of correct terminology (a precise language) is essential for communicating echocardiographic findings to other team members and for accurate documentation. Table 1, derived from the ECDP, summarizes qualitative and quantitative

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parameters with suggested descriptors for standardized reporting of MR mechanism and severity.

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Mechanism and etiology of chronic MR

The underlying mechanism, either primary or secondary, implies distinct disease processes of varying

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etiologies, with different management strategies and outcomes.4 Primary MR results from abnormal morphology of any of the valve components, including leaflets, annulus or chordae. On the other hand,

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secondary MR is a result of papillary muscle displacement and leaflet tethering due to adverse changes in

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LV size, shape or function, and is seen in cardiomyopathy of ischemic or non-ischemic origin.2 Comprehensive echocardiographic evaluation for chronic MR begins with a description of the mitral valve apparatus morphology, characterization of leaflet motion as well as determination of the above LV characteristics, thereby distinguishing between primary and secondary MR. The ECDP provides a comprehensive approach towards making this important distinction (See figure 1).

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The role of the cardiac anesthesiologist as a peri-interventional echocardiographer becomes all the more important if the pre-procedural evaluation is suboptimal, or if further intra-procedural characterization is required using TEE. Two-dimensional echocardiography (2DE) and color flow Doppler (CFD), chiefly using midesophageal windows (four chamber, commissural, two chamber and long axis views), enable

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characterization of MR mechanism and etiology. Additionally, three-dimensional echocardiographic (3DE) modalities are frequently used to make this distinction in conjunction with 2DE and CFD.11 Leaflet motion is described using the Carpentier classification scheme.12 Type I is associated with normal leaflet motion, and occurs either due to abnormal leaflet morphology such as vegetations, perforation, clefts or

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due to coaptation failure purely because of annular dilation . Type II, typically associated with primary MR, is characterized by excess leaflet motion due to leaflet, chordal or papillary muscle pathology, resulting in leaflet prolapse or flail.9 Prolapse has been echocardiographically defined as displacement of mitral leaflets 2 mm or more beyond the annular plane into the LA.13 More recently, the term ‗prolapse‘ is

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used to imply displacement of the free edge of the leaflet, whereas flail most often implies prolapse of the leaflet edge in association with chordal rupture.14 Type III lesions are usually related to secondary causes

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and are further broken down into Type IIIA and Type IIIB lesions. Type III A is typically seen in rheumatic or radiation-induced valvular heart disease, and involves restriction during both systole and

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diastole. Type IIIB involves restricted leaflet motion during systole only, and is suggestive of secondary

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MR due to ischemic or non-ischemic cardiomyopathy. As echocardiographic advances allow for a much more detailed evaluation of the mitral valve, the

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presence of mixed pathology is increasingly being recognized. Examples include LV dysfunction due to primary MR with subsequent leaflet tethering or chordal rupture seen in ischemic mitral disease. MR secondary to LA and annular dilation caused by long-standing AF (atrial functional MR) has also been described.15

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Severity assessment Accurate determination of the degree of MR, particularly the distinction between moderate and severe MR, is of utmost importance when determining a patient‘s candidacy for surgery or transcatheter therapy. While a detailed review of the American Society of Echocardiography (ASE) recommendations for

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perioperative evaluation of MR may be found elsewhere,16 table 2 summarizes the recommended qualitative and quantitative echocardiographic parameters used to evaluate and grade MR.

It is imperative to recognize that anesthesia and sedation typically lead to underestimation of MR severity. Ideally, the decision to proceed with an intervention based on MR severity should be made pre-

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procedurally. However, in practice, the intra-procedural input from the cardiac anesthesiologist is often relied upon for TEE grading of MR, especially when an MR intervention is being considered as a concomitant cardiac procedure. An unsatisfactory TTE exam or low confidence in preoperative assessment also prompts closer intra- procedural TEE re-evaluation of MR severity by the cardiac

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anesthesiologist.

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It is equally important for the cardiac anesthesiologist to recognize intrinsic limitations of individual echocardiographic parameters commonly used to grade the severity of MR. Accordingly, the cardiac

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anesthesiologist should refrain from using single parameters in isolation for arriving at conclusions.

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Impact of anesthesia on MR grading: There can be significant alterations in the loading conditions during the peri-procedural period due to the effects of sedation or anesthesia on sympathetic tone, the potential for myocardial depression, and due to the effect of positive pressure ventilation.17 This may result in significant underestimation of MR severity on TEE exam, making intra-procedural assessment and interpretation of severity a challenge for the cardiac anesthesiologist. Documentation of the hemodynamic parameters and any administered

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medications during serial MR grading may be prudent in order to ensure comparability of loading conditions.18 Hemodynamic manipulation with vasopressor administration to match baseline hemodynamic parameters has been shown to enhance accuracy of severity assessment. However, there is a risk of overestimation of MR with this approach, and the anesthesiologist should recognize the

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subsequent increased risk of unnecessary intervention.17 Beat-to-beat variability in MR severity may result from variable LV filling due to new onset intraoperative arrhythmias such as premature ventricular contractions,19 or due to positive pressure ventilation in the anesthetized patient.

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Given the possibility of misdiagnosis under anesthesia with or without hemodynamic matching, the preinterventional echocardiographic exam may serve as a better guide for the purpose of MR grading. Cautious interpretation of any findings under anesthesia is recommended.17 The patient‘s clinical findings may instead provide a clue to the progression of the disease and severity of MR, again highlighting the

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importance of a thorough clinical assessment by the cardiac anesthesiologist. Ideally, the decision to

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proceed with mitral valve intervention should be based on the pre-procedural echocardiographic evaluation, adjunctive testing, and clinical assessment of severity. Intraoperative TEE by the cardiac

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anesthesiologist is better utilized in defining valve pathoanatomy 20 as well as mechanism, in determining suitability for repair, and for determining the adequacy of the subsequent intervention. However, accurate

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intraoperative grading may become important for management decisions when MR is discovered incidentally during another cardiac procedure such as aortic valve replacement for aortic stenosis, or

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when preoperative testing is suboptimal.17

Limitations of Color Flow Doppler and Regurgitant Jet area There is often a temptation to grade MR based on the size of the regurgitant jet on CFD. However, CFD has several other intrinsic limitations in addition to the impact of anesthesia on the jet area. The 9

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regurgitant jet area is a function of jet velocity, and is impacted by hemodynamic variability. A high velocity jet, as occurs during conditions of increased afterload such as hypertension or aortic stenosis, results in an increased jet size on CFD, leading to potential overestimation of MR severity. Similarly, low velocity jets with small regurgitant jet area, despite severe MR, may be observed in the presence of

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decreased gradients due to LV dysfunction and elevated LA pressure.21 Jet eccentricity, with loss of momentum due to LA wall impingement, may also lead to underestimation of MR severity.22

For these reasons, guidelines recommend against independent use of MR jet size or area assessed by CFD for grading of MR severity.21 These considerations also hold true for intra-procedural assessment of MR

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severity using CFD, and should be taken into account by the cardiac anesthesiologist.

Limitations of Quantitative parameters

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Although highly useful, quantitative parameters including effective regurgitant orifice area (EROA), regurgitant volume (RVol) and regurgitant fraction (RF) have limitations that should be recognized.

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EROA can be measured using proximal isovelocity surface area (PISA) method, 3D imaging including

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3D vena contracta (VC) area method, and volumetric methods including CMR. PISA and VC width and area utilize single frame measures, potentially resulting in overestimation of MR severity when the

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regurgitant jet is not holosystolic.21 Temporal dynamicity within the cardiac cycle, such as the presence of biphasic flow during secondary mitral regurgitation,23 may also impact the reliability of these single frame Imprecise PISA radius measurements, or underestimation of jet velocity due to poor

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measures.

continuous wave Doppler (CWD) beam alignment will also result in erroneous EROA calculation. 21 The addition of multiple EROA calculations in the presence of multiple regurgitant jets has not been validated. RVol and RF values are often obtained by calculating the difference between mitral inflow and aortic stroke volumes. These stroke volumes are in turn derived from cross sectional areas of the mitral annulus and LVOT respectively. 2DE methods often incorrectly assume a circular mitral annulus and LVOT cross 10

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section, leading to erroneous quantification of RVol and RF.24 This method also assumes the absence of aortic regurgitation or intracardiac shunting, which may not necessarily be the case. Moreover, both EROA and RVol are dependent on LV volumes, and need to be considered in the context of LV total stroke volume when evaluating MR severity.25 RVol may be small in the presence of a small LV with low

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EF, despite the presence of severe MR and high RF,26 resulting in underestimation of actual severity. There are several other pitfalls specific to grading of secondary MR. The geometric assumption of a hemispherical PISA and circular EROA may not apply to secondary MR, in which the regurgitant orifice is often crescent- shaped. The 2D PISA derived EROA and VC width may therefore underestimate

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severity.27 Due to the potential for underestimation, the 2014 AHA/ACC guidelines reduced the EROA and RVol cut-off criteria for severe secondary MR to 0.2 cm2 and 30 ml respectively.2 Although this redefinition also made sense in light of data suggesting poorer outcomes when the higher original cut-off values were used, it also increased the likelihood of unnecessary surgical or transcatheter interventions. 25

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The 2017 update to the guidelines have therefore reverted back to the original cut-off values of 0.4cm2 and 60 ml, respectively, for defining severe secondary MR.3 Additionally, in secondary MR, the peak

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regurgitant velocity may not occur at the same instant when the PISA radius is maximum,18,23 resulting in

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inaccurate calculation of EROA using the PISA method. The above discussion serves to highlight the perils of considering echocardiographic parameters in

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isolation during perioperative assessment of severity. As such, the ASE emphasizes integration of

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multiple parameters for reliable interpretation.21

The integrated approach to evaluation of MR severity The ECDP and the ASE recommend an integrated approach towards the evaluation of MR severity and its classification into mild, moderate or severe. This approach is applicable to the peri-interventional evaluation of chronic MR patients as well. TTE is usually the first line modality, and multiple qualitative 11

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and quantitative echocardiographic parameters are considered in determining severity. When uncertainty persists due to discordance of echocardiographic parameters, or due to poor quality TTE imaging, the ECDP supports additional testing including TEE, left heart catheterization and cardiovascular magnetic resonance (CMR) imaging. TEE is the principle modality for characterization of MR intra-procedurally,

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and evaluation often includes severity assessment as well. Due to the increased difficulty in interpreting MR severity under anesthesia, it is all the more important for the cardiac anesthesiologist to approach echocardiographic assessment in a systematic fashion, and to integrate TEE findings with pre-procedural

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investigational and clinical data.

The approach to echocardiographic assessment of severity (Figure 2)

CFD, for the purpose of jet size evaluation, should only be utilized in the identification of MR and for

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formation of an initial impression of severity. The need for careful interpretation of CFD in the context of general anesthesia has been described above. Next, specific criteria including the VC width and PISA

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radius should be considered for classifying MR severity. A dominant mitral inflow A wave on pulsed wave Doppler (PWD) analysis, and the finding of a soft jet on CWD interrogation suggest mild MR. A

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normal or small LA and LV with a late systolic MR jet (or MR jet duration of less than 30% systole) is also suggestive of non-severe MR despite the presence of a large jet. Findings suggestive of severe MR

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include mitral inflow E wave velocity exceeding 1.2 m/s, holosystolic MR jet with a dense, triangular CWD profile with a jet velocity of less than 4.5m/s (reflecting elevated LA pressure), dilated LA or LV in

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the absence of any other cause, and elevated PA pressure.4 The sizes of the LV and LA serve as important clues to the extent of disease progression and severity of MR, and should be routinely evaluated using 2DE. The duration of the MR jet (late systolic versus holosystolic) is very useful in overcoming the limitation of parameters relying on single frame measurements such as PISA and VC.

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In situations of discordance, or when intermediate values are obtained, additional quantitative parameters including EROA, RVol and RF become essential for reliable MR grading. Based on these additional criteria, MR can be categorized into 4 grades (I to IV). Grade III has overlapping characteristics of moderate and severe MR,21 and is labelled as severe if more than 3 specific criteria are present, or if an

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elliptical orifice is seen (see figure 2).

The role of adjunctive testing

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The lack of reliability of echocardiographic grading of MR severity under anesthesia has been described above. Since MR severity is a key consideration for management decisions, accurate grading should be sought in the preoperative or pre- interventional period.

While preoperative echocardiographic grading of MR may be straightforward when multiple parameters

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agree with one another, additional testing complements the algorithmic approach in the presence of discordance. CMR is a particularly useful pre-operative modality for quantification of MR severity. In

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fact, available literature suggests greater accuracy of MRI determined regurgitant volume and MR severity when compared with TTE.28 CMR also aids in reliable assessment of LV size29 and function, and

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in identifying patients in need of surgery.30 PA and LA pressures measured by right heart catheterization

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aid in determination of severity as well. Other perioperative tools for evaluation of MR include left heart catheterization, LV angiography, and exercise echocardiography. Secondary MR of ischemic origin is

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particularly dynamic, and patients may be disproportionately symptomatic in relation to the observed mild degree of MR on resting echocardiography. Exercise echocardiography may be of diagnostic value in these situations as it is able to unmask severe MR and LV dysfunction in symptomatic patients. 31 Although not distinctly stated by guidelines, surgery in chronic primary MR patients may be indicated when systolic pulmonary artery pressure on stress echocardiography exceeds 60 mm Hg, as long as a durable repair is considered feasible.32 Exercise echocardiography also enables risk stratification, as 13

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demonstration of poor contractile reserve in minimally symptomatic MR patient may help predict postsurgical LV dysfunction.33 The cardiac anesthesiologist should give due consideration to these adjunctive

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tests while assessing MR severity intra or pre- procedurally.

New paradigms in severity assessment

Although not extensively discussed by the ECDP, the use of 3D color flow echocardiography may help to overcome some of the above-described limitations of 2DE and CFD, especially those encountered in

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assessment of secondary MR. 3D VC area is a measure of EROA that is not limited by the geometric assumptions of vena contracta width or 2D PISA derived EROA. It correlates well with integrative 2D parameters34 and can be applied in the setting of multiple jets.35 A cut-off value of 0.4 cm2 has been proposed to differentiate severe from moderate MR.34 It can be used to calculate RVol as well.24 Of note,

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further studies are required to evaluate the prognostic value of VC area and its relation with long-term outcomes.36

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Automated 3D PISA derived RVol is another useful parameter that is more accurate than the traditional

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2D PISA method for MR quantification, and correlates better with CMR in patients with functional MR.37 Additionally, the automated algorithmic software platform requires minimal user input and provides

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immediate measurements that are accurate and reproducible,38 making it well suited for the operating room environment. Finally, an integrated 3D PISA method utilizing multiple systolic frames that takes

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into account the temporal dynamicity of MR has been described, which prevents overestimation of MR and possibly avoids unnecessary interventions that may occur with reliance on single frame parameters. 39 Since use of these novel approaches may help increase accuracy of MR assessment, the cardiac anesthesiologist should consider incorporating 3D color flow echocardiography for intra- procedural evaluation of MR. If specific 3D parameters were utilized to define MR severity during the pre-

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interventional work-up, consistency in grading should be maintained by using the same techniques intraprocedurally.

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Treatment of Chronic MR Broadly speaking, mitral valve surgery is the treatment of choice for chronic severe primary MR. Patient symptomatology and LV function are other considerations when determining the appropriate management in these patients. In contrast, surgery may not provide a mortality benefit in secondary MR despite

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improvement in quality of life.40 Guideline directed medical therapy remains the preferred initial approach in chronic secondary MR,2 with limited indications for surgery as discussed below. The subsequent discussion will focus on relevant anesthetic considerations, hemodynamic goals, as well as current guidelines and knowledge that serve as guiding principles for the heart valve team and the cardiac

Hemodynamic goals in MR

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anesthesiologist involved in peri-interventional management decisions.

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Regardless of the etiology, the objective of hemodynamic management in MR is maintenance of forward

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flow. It is essential to maintain mild tachycardia, high normal to increased preload, reduced afterload, and normal contractility. The goal to increase heart rate and decrease afterload should however be balanced

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with the need for optimizing myocardial oxygen demand and supply, especially in secondary MR related to ischemia. It may be prudent to avoid excess LV filling to prevent further annular dilation and resultant worsening in regurgitation. Avoidance of hypoxemia, hypercarbia and acidosis becomes important to prevent further rise in PA pressure and RV decompensation.41 Optimization of fluid status, judicious use of inotropes and vasodilators with appropriate use of invasive hemodynamic monitors including the PA catheter, may help attain these goals.

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Surgical Treatment of Chronic MR The surgical approaches to correct MR chiefly include valve repair and replacement. Several factors such

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as patient symptomatology, severity and mechanism of MR, pathoanatomy of the mitral valve, and function and size of the LV are considered when deciding upon the need for surgery as well as the optimal approach. Furthermore, surgeon expertise is an important factor in deciding between the two approaches. In current practice, the cardiac anesthesiologist plays a crucial role in providing appropriate

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management recommendations based on integration of perioperative clinical and echocardiographic data. The ECDP highlights the updated guidelines for surgical management of MR, and provides a simplified algorithmic approach in deciding between repair and replacement of the valve (figure 3). While this simplified approach may serve as a useful guide for the cardiac anesthesiologist in the perioperative

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setting, several additional factors such as likelihood of SAM need to be taken into account for nuanced

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decision-making. 42

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Recommendations for surgical treatment of chronic primary MR In symptomatic patients with severe chronic primary MR (Stage D) and LVEF >30%: Guidelines strongly

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recommend mitral valve surgery, and in general, evidence overwhelmingly favors repair. 2,43 The

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European (ESC/EACTS) guidelines also recommend surgery in severe symptomatic chronic primary MR, and consider repair a class I recommendation.44 Asymptomatic patients with severe chronic primary MR, with preserved LV function (LVEF > 60%) and LV end systolic dimension (LVESD) less than 40 mm (Stage C1):Although mitral valve repair is associated with inherent surgical risk, evidence suggests that asymptomatic patients with severe degenerative MR are at high risk of experiencing adverse events including death with medical 16

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management alone.45 Additionally, a recent study determined that a preoperative EF <64% and LV endsystolic diameter (ESD) ≥37 mm was predictive of post-operative LV dysfunction.46 In light of this evidence, it indeed seems reasonable to proceed with mitral valve surgery in the asymptomatic patient prior to onset of LV dysfunction when LV EF and size progress towards 60 % and 40 mm respectively.

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Accordingly, as per recent updated guidelines, it is considered reasonable to repair the mitral valve in the asymptomatic patient with severe MR and preserved LV function and size (defined as LVEF > 60% and LV end systolic dimension < 40 mm), if serial imaging demonstrates progressive decrease in LV function or increase in LV size.3 Repair should be attempted in a heart valve center of excellence, only if the

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likelihood of durable repair is high (>95%), probability of residual MR is low, and expected mortality is <1%. Repair is also considered reasonable in the presence of recent onset AF or when resting pulmonary artery systolic pressures exceeds 50 mm Hg.

The European guidelines also recommend a similar approach to the asymptomatic chronic primary MR

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patient with normal LV function and size (LVESD 40-44 mm). These guidelines also consider repair to

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be reasonable in the asymptomatic patient with flail leaflet or dilated LA, as long as a durability is expected and surgical risk is deemed low. Similar to the AHA/ACC guidelines, repair is a class IIa

present.44

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recommendation in asymptomatic chronic primary MR patients when AF or pulmonary hypertension is

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Asymptomatic patient with severe chronic primary MR and LV dysfunction (Stage C2): Mitral valve surgery remains a class I recommendation for the asymptomatic patient with severe MR, when LVEF is

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30-60% and LVESD is greater than 40 mm.2 European guidelines recommend a similar approach when LVEF is less than 60% and LVESD > 45 mm.44 Patient with chronic moderate primary MR: Per recent AHA/ACC guidelines, mitral valve surgery is considered reasonable in this patient group if performed along with a concomitant cardiac procedure for a different indication.2 17

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Chronic primary MR: Advantages of repair As a general principle, repair is generally preferred over replacement in chronic primary MR, as long as it

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is considered feasible, and the risk of recurrence of MR and reoperation is low. 3 Details on the different repair techniques may be found elsewhere.47 Repair is believed to have several advantages including better preservation of LV function, absence of prosthetic valve related complications such as thromboembolism and need for routine anticoagulation,48 and possibly superior survival.49 Moreover, widespread use of intraoperative echocardiography in combination with advancement in repair techniques

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has led to improved feasibility, high success rate, as well as enhanced late durability in degenerative MR.50-52 A recently published analysis of data from the Mitral Regurgitation International Database confirmed reduced operative mortality, improved 20 year survival, as well as greater freedom from

group compared to replacement.43

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reoperation and valve related complications (including bleeding, stroke and endocarditis) in the repair

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Fibroelastic disease, especially that involving an isolated posterior segment, is the pathology considered most amenable to repair. Successful repair in the ideal patient may be associated with freedom from

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reoperation of around 90% of patients even after 10 years.51,53 In contrast, repair may be much more challenging in complex pathologies such as Barlow‘s disease with significant myxomatous changes, or in

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cases with anterior or bileaflet involvement. Anterior leaflet or bileaflet prolapse is an independent predictor of failure of repair and need for reoperation due to recurrence of MR.54 Although excellent

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results may be obtained in experienced high volume centers,55 there is a higher reported incidence of MR recurrence following mitral valve repair in Barlow‘s disease. 56 The relative risk of reoperation following anterior leaflet repair has also been found to be higher in comparison to patients undergoing repair for posterior leaflet prolapse.53 The survival benefit of repair may be lost in older patients with these complex mitral pathologies, as demonstrated in a propensity matched sub group analysis of a study.57 The decision

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to repair or replace in such patients should be more nuanced. The optimal approach in the elderly is a subject of debate, with data suggesting an increased likelihood of replacement due to presence of comorbidities, and due to the perceived lack of long-term benefit in a patient population with limited life expectancy.58 The benefit of avoidance of anticoagulation is lost if MAZE or ablation procedures are not

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planned for co-existing atrial fibrillation, or if patients are expected to remain in post repair atrial fibrillation. Other considerations include surgeon and institutional experience, and the need to perform concomitant valve interventions such as aortic valve replacement (with concern for increased risk of endocarditis and thromboembolic complications with double valve replacement).59

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A greater likelihood of post repair systolic anterior motion (SAM) and LV outflow tract obstruction (LVOTO) may also influence the surgical technique. A small left ventricle ( LV end diastolic diameter of less than 45 mm), an aorto-mitral angle less than 120°, Septal hypertrophy (basal septal diameter greater than 15 mm), and a tall posterior leaflet (exceeding 15 mm) independently predict SAM. 60 Additionally, a

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C-sept distance (distance between the mitral leaflet coaptation point and septum) of less than 2.53 cm, and an anterior to posterior leaflet length ratio of less than 1.3, predict post repair SAM in patients with

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myxomatous disease.61 Although extrapolation of these results to patient populations with nonmyxomatous disease should be done with caution, these predictors are reflective of a coaptation point that

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is displaced anteriorly into the LVOT and indicate the possibility of post mitral repair SAM and LVOTO.

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Intraoperative recognition of these echocardiographic predictors by the cardiac anesthesiologist will enable the surgeon to apply appropriate surgical techniques to minimize the risk of occurrence. Further

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resection in height of posterior leaflet (to less than 15 mm), use of a larger or partial annuloplasty ring, performance of Alfieri repair, and even prophylactic septal myectomy (in presence of septal bulge) are techniques that should be considered.42 To summarize, the AHA/ACC guidelines recommend repair over replacement as a class I indication for chronic primary MR when the pathology is restricted to the posterior leaflet.2 The guidelines also recommend against valve replacement for the treatment of isolated severe primary MR limited to less 19

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than one half of the posterior leaflet unless mitral valve repair has been unsuccessfully attempted. In cases of anterior or bileaflet pathology, repair is recommended when the likelihood of a successful and durable repair is high.2 Replacement may be considered in Carpentier type I (such as endocarditis) or Carpentier type IIIa etiologies (like rheumatic heart disease) if otherwise deemed unrepairable.4 Since high volume

experienced mitral valve surgeon at a center of excellence.

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The heart valve team and ‗center of excellence‘ for mitral valve repair

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centers are more likely to attempt repair,62 patients with repairable lesions are best served by referral to an

Since guidelines support early repair in the asymptomatic patient with chronic severe primary MR even in the presence of complex pathoanatomy, and since sicker patients are being considered for intervention, the need to refer patients to dedicated centers has become all the more important. The ECDP as well as

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European guidelines duly acknowledge the role of the multi-disciplinary heart valve team and emphasize on the need for referral to a comprehensive valve center in order to maximize success.44

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Health care facilities and cardiac surgeons may differ significantly in terms of experience, mitral surgical volumes, repair rate and outcomes. To ensure appropriate referral, it is important to define what

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constitutes a center of excellence for mitral valve repair. 63 According to recent AHA/ACC guidelines for

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valvular heart disease, the ‗Heart Valve Centers of Excellence‘ should have multidisciplinary experts, including anesthesiologists in the perioperative setting, collaborating in patient care. 2 They should offer

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advanced diagnostic modalities including peri-procedural imaging, as well as management options including valve surgery, aortic surgery and transcatheter therapies. Additionally, they should participate in national outcome registries, adhere to guidelines, participate in ongoing evaluation and quality improvement processes and publically share outcome data.2 Other proposed standards include transparency in sharing data related to repair rate and durability.63 Although center or surgeon specific volumes is an imperfect surrogate for outcomes, mitral valve repair requires considerable expertise,64 and 20

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is more likely to be attempted at a high volume center.62 As such, it may also be important to determine a minimum mitral valve surgical volume (institutional as well as individual surgeons‘) towards defining a center of excellence for mitral repair. Currently there is absence of broad consensus on annual thresholds

Chronic severe secondary MR (Stage C or D):

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Recommendations for surgery in chronic secondary MR

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applicable to this definition.

Despite lack of survival benefit in patients with chronic secondary MR, multiple studies have demonstrated low operative mortality and subsequent improvement in New York Heart Association

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(NYHA) functional class and quality of life following mitral valve surgery. 65 As per AHA/ACC guidelines, mitral valve surgery is reasonable in patients with chronic severe secondary MR (Stage C and

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D) while undergoing concomitant cardiac surgical procedures such as coronary artery bypass grafting (CABG) or aortic valve replacement (AVR).2

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Additionally, per guidelines, symptomatic patients with chronic severe secondary MR (Stage D; NYHA

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class III or IV), who remain unresponsive to medical therapy (including cardiac resynchronization therapy), may also be considered for isolated MV surgery if revascularization is not an option. It should

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be recognized that while this approach may reduce LV size and optimize myocardial oxygen demand supply ratio, it may not halt further progression of underlying cardiomyopathy.2 In light of questionable survival benefit, it may in fact be prudent to consider other non-surgical therapies instead of isolated mitral valve surgery especially when the surgical risk is considered prohibitively high. European guidelines recommend percutaneous edge-to-edge repair (or other transcatheter therapies) in symptomatic patients with LVEF less than 30% or when surgical risk is otherwise considered to be high regardless of

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severity of LV function.44 Surgery may however be considered when revascularization is indicated and considered feasible, despite the presence of severe LV dysfunction.44

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Chronic secondary MR: Advantages of replacement With previous data suggesting improved long and short-term survival in comparison with replacement,66 undersized annuloplasty was earlier considered standard surgical treatment of secondary MR of ischemic origin. However, most of the literature supporting this approach included retrospective observational

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studies and meta-analysis. Subsequent data showed a high incidence of recurrence in secondary MR patients who underwent annuloplasty.67 Furthermore, a recent randomized controlled trial showed no significant difference in the LVESV index, rate of composite of major adverse cardiac or neurological events, and functional status or quality of life parameters between repair and replacement groups at the

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end of 12 months.68 The same study also demonstrated a significantly higher rate of recurrence of moderate or severe MR in the repair group. At two- year follow-up, the patients in the repair group also

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had a higher incidence of heart failure.69 In conclusion, chordal sparing mitral valve replacement is not only more durable than repair with fewer heart failure rated adverse outcomes, it is also associated with

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comparable LV reverse modeling and survival.

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In light of the above observations, the 2017 focused update to the 2014 AHA/ACC guidelines states that it may be beneficial to choose chordal sparing mitral valve replacement over undersized annuloplasty

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among symptomatic patients undergoing mitral valve surgery for chronic severe secondary MR.3 If however mitral valve repair is considered patients with secondary MR, the cardiac anesthesiologist should first rule out echocardiographic predictors of annuloplasty failure. These predictors include coaptation depth ≥ 11 mm, tenting area ≥ 1.6 cm2, mitral annular diameter ≥ 3.7 cm, posterior annular angle > 45 degree and the presence of LV enlargement.11,,70,71 It may be preferable to choose valve replacement over repair with these findings. 22

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Chronic moderate secondary MR (Stage B) Due the progressive nature of the mitral regurgitant disease process, the 2014 AHA/ACC guidelines

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recommend considering mitral valve repair for chronic moderate secondary MR if cardiac surgery were to be performed for another indication.2 However, a recent 2-year follow up of patients with coronary artery disease and moderate MR in a randomized trial failed to show any advantage of combined mitral valve repair and CABG versus CABG alone in terms of LV reverse modeling or survival. In fact, patients who underwent combined treatment had longer cardiopulmonary bypass times, and experienced a higher

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incidence of neurological events and arrhythmias.72 In light of this evidence, additional mitral valve surgery for moderate secondary MR may not provide any meaningful benefit to patients undergoing

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CABG. This is well reflected in the 2017 focused update of AHA/ACC guidelines.3

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Transcatheter Therapy

Following the success of transcatheter aortic valve replacement (TAVR), device companies have

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remained in constant pursuit of novel transcatheter cardiac therapies. One such device from these efforts is the edge-to-edge clip repair device for mitral regurgitation. In 2013, the FDA approved the use of this

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device for percutaneous treatment of significant (≥ 3+) symptomatic MR (i.e. stage C and D disease) due to primary abnormality of the mitral apparatus in those patients deemed to have prohibitive risk for mitral

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valve surgery. As this is the only FDA approved device for the treatment of primary MR, the ECDP limits its brief discussion on transcatheter therapies for MR to this specific device. Figure 4 depicts the ECDP algorithm for determining eligibility for this device. Edge-to-Edge repair Data

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The mitral clip device has been evaluated through the Endovascular Valve Edge-to-Edge Repair Study (EVEREST) I and EVEREST II trials. EVEREST I was a safety and feasibility trial with 55 patients and EVEREST II was an efficacy trial that enrolled 279 patients.73 EVEREST II randomized patients to either edge-to-edge clip repair or surgical treatment in a 2:1 fashion. The primary composite efficacy endpoint,

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which included freedom from death, from surgery, and from recurrence of significant MR at 12 months, favored the surgical group. The main driver of this difference in outcomes was that 20% of the percutaneously treated patients eventually required surgical correction. Among those who had significant improvement in MR with percutaneous therapy, 78% continued to remain free from surgery at 2 years. 74

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It should be noted that many safety endpoints, including transfusion of more than 2 units of blood and the need for over 48 hours of ventilatory support, were lower in the percutaneous arm. In light of these findings, FDA restricted its use only to those primary MR patients considered to have prohibitive risk for surgery. Since the device‘s approval in 2013, several thousand patients have been registered in the

TVT) Registry for this indication.

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Society of Thoracic Surgery/American College of Cardiology Transcatheter Valve Therapy (STS/ACC

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From a perioperative physician‘s perspective, several considerations about the available data and recommendations must be made as these patients present for percutaneous treatment of MR. First, all

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patients in the EVEREST II study were considered surgical candidates. Secondly, patients with a LVEF

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below 25% or LVESD over 55 mm were excluded. Lastly, patients from the EVEREST trials predominantly had primary MR. Therefore, the best-studied patient group for edge-to-edge repair in the

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United States has been the patient with primary MR due to prolapse or flail with reasonable left ventricular function and size. When reviewing the ECDP, it is important to recognize that these patients are at the center of the discussion; this essentially describes who the device is intended for and what personnel make up a heart valve team. Since the EVEREST trials, prospective registry data has demonstrated a lasting reduction in both MR and heart failure symptoms at one year with edge- to-edge repair in high-risk patients with labeled indications.73 How this data translates into safety and efficacy for

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patients with mixed lesions or purely functional MR remains largely unknown. The ECDP does however provide a chart to guide perioperative physicians on predicting potential difficult cases. The chart classifies the feasibility of the procedure into ideal, challenging or as relatively contraindicated based on echocardiographic findings. In summary, patients with large MV areas (>4cm2), mean transmitral

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gradient ≤4 mm Hg, primarily A2/P2 segmental lesions with small flail gap heights (<1cm) are most ideal for this therapy. Relative contraindications include mitral valve area <4 cm2, mean gradient ≥4 mm Hg, and rheumatic or heavily calcified valves. Several patients may fall in the middle of the spectrum, i.e. ―challenging‖, without having relative contraindications. These include patients with flail segment widths

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over 1.5 cm and Carpentier class IIIB lesions. It is however noteworthy that while some restrictive leaflets may be relatively easy to clip, flail segments in primary MR may occasionally be technically challenging, requiring rapid pacing or anchor techniques to grasp.75,76 The ECDP does not make distinctions to this level of detail.

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Of note, European trials on patients with secondary MR have reported favorable outcomes with significant reduction in MR in most patients.77 In the United States, the ongoing randomized

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Cardiovascular Outcomes Assessment of MitraClip Therapy in Heart Failure Patients with Functional Mitral Regurgitation (COAPT) specifically evaluates patients with secondary MR. Superiority over

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medical therapy, and MR recurrence rates are yet to be determined. Anecdotally, many patients

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undergoing percutaneous therapy for secondary MR have been receiving clip devices on-label, based on having mixed lesions. As more data for edge-to-edge therapy in functional MR becomes available,

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approval for use in secondary MR may be obtained. In this case, the ECDP will need to be modified to capture this patient group. Already known ―challenging‖ cases in this patient group include, restrictive lesions with tenting depths over 1 cm.

Edge-to-Edge repair procedure steps

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Given that the intent of the ECDP is to provide guidance on therapy choice, nuanced recommendations on specific clip methodology are not discussed. TEE and fluoroscopy are essential for guidance of the intervention. In brief, the Edge-to-Edge repair involves femoral venous access. A trans-septal puncture is performed at the posterior and superior aspect of the inter-atrial septum under TEE guidance, which

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allows for appropriate angulation when subsequently grasping the mitral leaflets with the device. The four-chamber view is used to measure height of the puncture site from the mitral commissure. A guidewire is then inserted through the puncture into the LA and typically directed towards the left upper pulmonary vein. Following placement of a steerable guide over the wire, a clip delivery system is

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introduced into the LA through the guide and angulated towards the mitral leaflets clearing the coumadin ridge. The arms of the clip are opened and oriented perpendicular to the commissure prior to advancing the clip past the leaflets into the LV. Once appropriately positioned under TEE visualization, the leaflets are grasped between the arms and the device grippers. The important TEE views for guidance of the

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procedure include 2D mid-esophageal bicaval, aortic short axis, aortic long axis and the bicommissural

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views, as well as the 3D en-face view of the mitral valve.

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Edge-to-Edge repair trouble shooting

As mentioned, rapid pacing to reduce leaflet excursion, adenosine for holding mitral leaflets in their

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diastolic position, and anchoring with multiple clips starting from the commissural edge of a flail segment, are all described techniques for technically difficult cases. Familiarity with these described

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methods are imperative for successful clip repair in challenging cases. The use of the mitral valve vena contracta length, a novel measure using 3D color image data set of the mitral valve, may help in predicting the number of clips needed to reduce MR,78 thereby aiding peri-procedural planning in anticipated challenging scenarios. Further evaluation of these techniques and parameters are required

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before potential incorporation into guidelines. Further break down of challenging cases with recommended approaches could be useful in future updates as more data becomes available.

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Other novel therapies One final emerging treatment for mitral regurgitation not reviewed by the ECDP is transcatheter mitral valve replacement (TMVR). This technology is still in development and multiple devices are already in trial. Valve-in-valve replacement for patients with previous bioprosthetic valves, failed ring repairs, and

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replacement in patients with severe circumferential annular mitral calcium (valve in MAC) have been performed using both TAVR valves and novel devices.79,80 Trials with novel devices in native mitral valves are ongoing.81 As feasibility trials reach completion and these devices come to market, the ECDP

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would need to be modified to provide recommendations and indications for their optimal use.

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CONCLUSION

As perioperative physicians and experts in perioperative echocardiography, the cardiac anesthesiologist is

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in the unique position to contribute to procedural planning and provide recommendations for management

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of chronic MR patients presenting for intervention. A detailed clinical assessment complements cardiac investigations, enables pre-procedural optimization, and guides anesthetic management as well as patient

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prognostication. Accurate echocardiographic data including mechanism, etiology and severity of chronic MR, integrated with clinical data is a prerequisite for formulating optimal management strategies (see table 3). The management of MR, particularly transcatheter therapy, is an evolving field, and it is imperative for the cardiac anesthesiologist to keep pace with this rapidly growing field. The ECDP, and this review, may serve as important resources to guide the cardiac anesthesiologist involved in the care of these complex patients.

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FIGURE LEGEND LIST Figure 1: Algorithm for Distinguishing Primary from Secondary MR using Carpentier Classification (From O'Gara PT, Grayburn PA, Badhwar V et al. 2017 ACC Expert Consensus Decision Pathway on the Management of Mitral Regurgitation: A Report of the American College of Cardiology Task Force on

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Expert Consensus Decision Pathways. J Am Coll Cardiol. 2017;70:2421-2449)

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Figure 2: Algorithmic Approach to Assessment of MR severity. VCW = vena contracta width; PISA = proximal isovelocity surface area; VCA = vena contracta area; EROA= effective regurgitant orifice area; RVol = regurgitant volume; RF= regurgitant fraction (From O'Gara PT, Grayburn PA, Badhwar V et al. 2017 ACC Expert Consensus Decision Pathway on the Management of Mitral Regurgitation: A Report of

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the American College of Cardiology Task Force on Expert Consensus Decision Pathways. J Am Coll

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Cardiol. 2017;70:2421-2449)

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Figure 3: Decision tree for determining surgical mitral valve repair versus replacement in patients with severe MR (Adapted from O'Gara PT, Grayburn PA, Badhwar V et al. 2017 ACC Expert Consensus Decision Pathway on the Management of Mitral Regurgitation: A Report of the American College of Cardiology Task Force on Expert Consensus Decision Pathways. J Am Coll Cardiol. 2017;70:2421-

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2449)

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Figure 4: Determining Eligibility for Edge-to Edge Mitral Valve Clip (From O'Gara PT, Grayburn PA,

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Badhwar V et al. 2017 ACC Expert Consensus Decision Pathway on the Management of Mitral Regurgitation: A Report of the American College of Cardiology Task Force on Expert Consensus

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Decision Pathways. J Am Coll Cardiol. 2017;70:2421-2449)

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52. Braunberger E, Deloche A, Berrebi A et al. Very long‐term results (more than 20 years) of valve repair with Carpentier's techniques in nonrheumatic mitral valve insufficiency. Circulation. 2001;104:112-15.

for Mitral Valve Prolapse. Circulation. 2001;104:I1-I7.

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53. Mohty D, Orszulak TA, Schaff HV. Very Long-Term Survival and Durability of Mitral Valve Repair

54. David, Tirone E , Ivanov J, Armstrong S et al. A comparison of outcomes of mitral valve repair for degenerative disease with posterior, anterior, and bileaflet prolapse. The Journal of Thoracic and

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Cardiovascular Surgery. 2005;30:1242 -49.

55. Melnitchouk SI, Seeburger J, Kaeding AF et al. Barlow‘s mitral valve disease: results of conventional and minimally invasive repair approaches. Annals of Cardiothoracic Surgery. 2013;2:768-773. 56. Flameng W, Meuris B, Herijgers P, et al. Durability of mitral valve repair in Barlow disease versus

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fibroelastic deficiency. J Thorac Cardiovasc Surg. 2008;135:274-82

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College of Cardiology. 2014 Oct 28;64(17):1814-9.

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Table 1

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Table 2. Parameter

Mild

Moderate

LA size

Normal

Normal-dilated

Jet area

Small brief

Variable

Severe

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CW jet

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Qualitative:

Faint

Severely dilated

Central->50% LA

Eccentric-Wall-hugging

Dense, partial or

Holosystolic, dense and

parabolic

triangular

Variable

0.7

<0.2

0.2-0.39

0.4

RVol (ml)

<30

30-59

60

RF (%)

<30

30-49

50

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morphology

2

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EROA (cm )

<0.3

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VC Width (cm)

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Quantitative:

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Table 3.

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A multidisciplinary approach is central to the care of chronic MR patients, and the anesthesiologist plays an important role in the peri-procedural care as a member of the heart valve team Comprehensive pre-procedural clinical evaluation is essential to assess disease progression, and in conjunction with pre-procedural testing influences anesthetic management and patient prognosis. Patient symptomatology is an important consideration for surgical or transcatheter intervention Intraoperative TEE is a class I indication for chronic primary MR evaluation and for guidance of repair. TEE is also useful for evaluating prosthetic valve function following MV replacement, and is a requirement during transcatheter edge-to edge repair of the mitral valve While TEE is invaluable for defining MR mechanism and etiology intra-procedurally, severity is best determined in the pre- procedural period due to impact of anesthesia on its assessment. A knowledge of echocardiographic limitations, incorporation of newer 3D modalities, and utilization of an integrated approach in severity assessment is essential for optimal peri-procedural decisionmaking Repair is generally preferred over replacement for management of chronic primary MR. It is reasonable to repair the mitral valve in the asymptomatic patient with severe MR despite preserved LV function and size if serial imaging demonstrates progressive decrease in LV function or increase in LV size Chordal sparing mitral valve replacement should be considered instead of undersized annuloplasty in the symptomatic chronic secondary MR patient undergoing MV surgery. Additional mitral valve surgery for moderate secondary MR may not provide any meaningful benefit to patients undergoing CABG Edge-to edge repair of mitral valve and other emerging transcatheter therapies are expected to gain increasing importance, requiring familiarization by the cardiac anesthesiologist and subsequent incorporation in the current ECDP

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