Acute Mitral Regurgitation Guidelines

Guidelines are available from the following organizations for mitral valve regurgitation:

• American College of Cardiology/American Heart Association (ACC/AHA) (2014, 2017) ^{[4, 5]}
• American Association for Thoracic Surgery (2016) ^[6]
• European Society of Cardiology/European Association for Cardio-Thoracic Surgery (ESC/EACTS) (2017) ^[7]

In 2014 and 2017, the American Heart Association and American College of Cardiology (AHA/ACC) released revisions and focused updates, respectively, to their 2008 guidelines for management of patients with valvular heart disease (VHD). ^{[4, 5]}

The recommendations did not include acute mitral regurgitation (MR) but provided guidance for chronic primary and secondary MR. ^{[4, 5]}  

Chronic primary MR

The guidelines note that when assessing chronic MR, it is important to distinguish between chronic primary (degenerative) MR and chronic secondary (functional) MR, as these conditions have more differences than similarities. ^{[4, 5]}  Note the following about chronic primary MR ^[4] :

• Valve incompetence is due to pathology of  one or more of the valve components (leaflets, chordae tendineae, papillary muscles, annulus). Systolic regurgitation of blood from the left ventricle (LV) to the left atrium (LA) ensues.
• In developed nations, mitral valve prolapse is the most common etiology.
• Younger patients: Severe myxomatous degeneration with gross redundancy of anterior and posterior leaflets and the chordal apparatus (Barlow valve)
• Older patients: Fibroelastic deficiency disease, wherein lack of connective tissue results in chordal rupture.

Diagnosis and follow-up

◊ Class I recommendations

Transthoracic echocardiography (TTE) is indicated for baseline evaluation of LV size and function, right ventricular (RV) function and LA size, pulmonary artery pressure, and the mechanism and severity of primarly MR (stages A to D) in any patient  with suspected chronic primary MR (level of evidence [LOE]: B).

Cardiac magnetic resonance imaging (CMRI) is indicated in patients with chronic primary MR to assess LV and RV volumes, function, or MR severity and when these issues are not satisfactorily addressed by TTE (LOE: B).

Intraoperative transesophageal echocardiography (TEE) is indicated to establish the anatomic basis for chronic primary MR (stages C and D) and to guide repair (LOE: B).

Esophageal echocardiography is indicated for evaluation of patients with chronic primary MR (stages B to D) in whom noninvasive imaging provides nondiagnostic information about the MR severity, MR mechanism, and/or LV functional status (LOE: C).

◊ Class IIa recommendations

Exercise hemodynamics with either Doppler echocardiography or cardiac catheterization is reasonable in symptomatic patients with chronic primary MR where there is a discrepancy between symptoms and the severity of MR at rest (stages B and C) (LOE: B).

Exercise treadmill testing can be useful in patients with chronic primary MR to establish symptom status and exercise tolerance (stages B and C) (LOE: C).

Medical therapy

◊ Class IIa recommendations

Medical therapy for systolic dysfunction is reasonable in symptomatic patients with chronic primary MR (stage D) and LV ejection fraction (EF) less than 60% in whom surgery is not contemplated (LOE: B).

◊ Class III: No benefit

Vasodilator therapy is not indicated for normotensive, asymptomatic patients with chronic primary MR (stages B and C1) and normal systolic LV function (LOE: B).

Intervention

◊ Class I recommendations

Mitral valve surgery is recommended for symptomatic patients with chronic severe primary MR (stage D) and LVEF greater than 30% (LOE: B).

Mitral valve surgery is recommended for asymptomatic patients with chronic severe primary MR and LV dysfunction (LVEF 30% to 60% and/or LV end-systolic diameter [ESD] ≥40 mm, stage C2) (LOE: B)

Mitral valve repair is preferred to mitral valve replacement (MVR) when surgical treatment is indicated for patients with chronic severe primary MR limited to the posterior leaflet (LOE: B).

Mitral valve repair is preferred to MVR when surgical treatment is indicated for patients with chronic severe primary MR involving the anterior leaflet or both leaflets when a successful and durable repair can be accomplished (LOE: B)

Concomitant mitral valve repair or MVR is indicated in patients with chronic severe primary MR undergoing cardiac surgery for other indications (LOE: B)

◊ Class IIa recommendations

Mitral valve repair is reasonable in asymptomatic patients with chronic severe primary MR (stage C1) with preserved LV function (LVEF >60% and LVESD < 40 mm) in whom the likelihood of a successful and durable repair without residual MR is greater than 95% with an expected mortality rate of less than 1% when performed at a Heart Valve Center of Excellence (LOE: B).

Mitral valve repair is reasonable for asymptomatic patients with chronic severe primary MR (stage C1) and preserved LV function  (LVEF >60% and LVESD < 40 mm) with a progressive increase in LV size or decrease in ejection fraction on serial imaging studies (LOE: C-limited data).

Mitral valve repair is reasonable for asymptomatic patients with chronic severe nonrheumatic primary MR (stage C1) and preserved LV function (LVEF >60% and LVESD < 40 mm) in whom there is a high likelihood of a successful and durable repair with 1) new onset of atrial fibrillation [AF] or 2) resting pulmonary hypertension (pulmonary artery systolic arterial pressure >50 mm Hg) (LOE: B).

Concomitant mitral valve repair is reasonable in patients with chronic moderate primary MR (stage B) when undergoing cardiac surgery for other indications (LOE: C).

◊ Class IIb recommendations

Mitral valve surgery may be considered in symptomatic patients with chronic severe primary MR and an LVEF of up to 30% (stage D) (LOE: C).

Mitral valve repair may be considered in patients with rheumatic mitral valve disease when surgical treatment is indicated if a durable and successful repair is likely or when the reliability of long-term anticoagulation management is questionable (LOE: B).

Transcatheter mitral valve repair may be considered for severely symptomatic patients (New York Heart Association [NYHA] class III to IV) with chronic severe primary MR (stage D) who have favorable anatomy for the repair procedure and a reasonable life expectancy but who have a prohibitive surgical risk because of severe comorbidities and remain severely symptomatic despite optimal guideline-directed medical therapy (GDMT) for heart failure (HF) (LOE: B).

◊ Class III: Harm

MVR should not be performed for the treatment of isolated severe primary MR limited to less than one half of the posterior leaflet unless mitral valve repair has been attempted and was unsuccessful (LOE: B).

Chronic secondary MR

Diagnosis and follow-up

◊ Class I recommendations

TTE is useful to establish the etiology of chronic secondary MR (stages B to D) and the extent and location of wall motion abnormalities, and to assess global LV function, MR severity, and magnitude of pulmonary hypertension (LOE: C).

Noninvasive imaging (stress nuclear/positron emission tomography, CMRI, or stress echocardiography), cardiac computed tomography (CT) angiography, or cardiac catheterization, including coronary arteriography, is useful to establish the etiology of chronic secondary MR (stages B to D) and/or to assess myocardial viability, which in turn may influence management of functional MR (LOE: C).

Medical therapy

◊ Class I recommendations

Patients with chronic secondary MR (stages B to D) and HF with reduced LVEF should receive standard GDMT therapy for HF, including angiotensin-converting enzyme inhibitors (ACEIs), angiotensin-receptor blockers (ARBs), beta blockers, and/or aldosterone antagonists as indicated (LOE: A).

Cardiac resynchronization therapy (CRT) with biventricular pacing is recommended for symptomatic patients with chronic severe secondary MR (stages B to D) who meet the indications for device therapy (LOE: A).

Intervention

◊ Class IIa recommendations

Mitral valve surgery is reasonable for patients with chronic severe secondary MR (stages C and D) who are undergoing CABG or aortic valve replacement (AVR) (LOE: C).

It is reasonable to choose chordal-sparing MVR over downsized annuloplasty repair if operation is considered for severely symptomatic patients  (NYHA class III-IV) with chronic severe ischemic MR (stage D) and persistent symptoms despite GDMT for HF (LOE: B-randomized trial data).

◊ Class IIb recommendations

Mitral valve repair or replacement may be considered for severely symptomatic patients (NYHA class III-IV) with chronic severe secondary MR (stage D) who have persistent symptoms despite optimal GDMT for HF (LOE: B).

In patients with chronic, moderate, ischemic MR (state B) undergoing CABG, the usefulness of mitral valve repair is uncertain (LOE: B-randomized trial data).

Mitral valve repair may be considered for patients with chronic moderate secondary MR (stage B) who are undergoing other cardiac surgery. (LOE: C).

In 2016, the American Association for Thoracic Surgery (AATS) released updates to their 2015 consensus guidelines for ischemic mitral valve regurgitation (IMR). ^[6]

Moderate ischemic MR

In patients with moderate IMR undergoing coronary artery bypass grafting (CABG), mitral valve repair with an undersized complete rigid annuloplasty ring may be considered.

Severe ischemic MR

Mitral valve replacement is reasonable in patients with severe IMR who remain symptomatic despite guideline-directed medical and cardiac device therapy, and who have a basal aneurysm/dyskinesis, significant leaflet tethering, and/or severe left ventricle dilation (left ventricular end diastolic diameter [LVEDD] >6.5 cm).

Mitral valve repair with an undersized complete rigid annuloplasty ring may be considered in patients with severe IMR who remain symptomatic despite guideline-directed medical and cardiac device therapy and who do not have a basal aneurysm/dyskinesis, significant leaflet tethering, or severe left ventricle enlargement.

Mitral valve replacement versus repair

Mitral valve repair for IMR is performed with complete preservation of both anterior and posterior leaflet chords.

Mitral valve repair for IMR is performed with a small, undersized, complete rigid annuloplasty ring.

The European Society of Cardiology (ESC) and the European Association for Cardio-Thoracic Surgery (EACTS) released their guidelines for the management of valvular heart disease in 2017. ^[7] Their recommendations for intervention in mitral regurgitation (MR) are outlined below.

Severe primary MR

Class I recommendations

Mitral valve repair should be the preferred technique when the results are expected to be durable (level of evidence [LOE]: C).

Surgery is indicated in symptomatic patients whose left ventricular (LV) ejection fraction (EF) are over 30%, as well as in asymptomatic patients with LV dysfunction (LV end-systolic diameter [ESD] ≥45 mm and/or LVEF ≤60%) (both LOE: B).

Class IIa recommendations

Consider surgery in asymptomatic patients with preserved LV function (LVEF >60%) and the following:

• LVESD < 45 mm, and atrial fibrillation secondary to MR or pulmonary hypertension (systolic pulmonary pressure at rest >50 mm Hg) (LOE: B)
• LVESD of 40-44 mm, when durable repair is likely, surgical risk is low, and the repair is performed in a heart valve center, and in the presence of at least flail leaflet or significant left atrial (LA) dilatation (volume index ≥60 mL/m ² [body surface area BSA]) in sinus rhythm (LOE: C).

Consider mitral valve repair in symptomatic patients with LV dysfunction (LVEF < 30% and/or LVESD > 55 mm) refractory to medical management in the setting of a high likelihood of successful repair and low comorbidity (LOE: C).

Class IIb recommendations (all LOE: C)

Mitral valve repair may be considered in symptomatic patients with severe LV dysfunction (LVEF < 30% and/or LVESD > 55 mm) refractory to medical management in the setting of a low likelihood of successful repair and low comorbidity.

Percutaneous edge-to-edge procedure may be considered in patients with symptomatic severe primary MR who fulfill the echocardiographic eligibility criteria and who the heart team judge to be inoperable or at high surgical risk, avoiding futility.

Chronic secondary MR

Class I recommendation

Surgery is indicated in patients with severe secondary MR undergoing coronary artery bypass grafting (CABG) and LVEF above 30% (LOE: C).

Class IIa recommendation

Consider surgery in symptomatic patients with severe secondary MR, LVEF below 30% but with an option for revascularization and evidence of myocardial viability (LOE: C).

Class IIb recommendations (all LOE: C)

When revascularization is not indicated, surgery may be considered in patients with severe secondary MR and LVEF above 30% who remain symptomatic despite optimal medical management (including cardiac resynchronization therapy [CRT] if indicated) and have a low surgical risk.

When revascularization is not indicated and surgical risk is not low, a percutaneous edge-to-edge procedure may be considered in patients with severe secondary MR and LVEF over 30% who remain symptomatic despite optimal medical management (including CRT if indicated) and who have a suitable valve morphology as shown on echocardiography, avoiding futility.

In patients with severe secondary MR and LVEF below 30% who remain symptomatic despite optimal medical management (including CRT if indicated) and who have no option for revascularization, the heart team may consider a percutaneous edge-to-edge procedure or valve surgery after careful evaluation for ventricular assist device (VAD) or heart transplant based on individual patient characteristics.