Mitral Regurgitation Treatment & Management

Key considerations regarding treatment from the 2017 American College of Cardiology (ACC) expert consensus decision pathway on the management of mitral regurgitation (MR) include the following ^{[11, 12]} :

• Decisions regarding the optimal treatment of chronic MR are based on multiple variables, including MR type, MR severity, hemodynamic consequences, disease stage, patient comorbidities, and the experience of the heart valve team and its members.

• The principal intervention for primary MR is surgery; however, transcatheter mitral valve repair using an edge-to-edge clip plays a very limited role. Whenever feasible, mitral valve repair is strongly preferred over mitral valve replacement for primary MR.

• Surgical treatment for secondary MR should be considered only after appropriate medical and device therapies have been instituted. 

• Common techniques for mitral valve repair for primary MR include nonresection techniques using artificial chords or ipsilateral chordal transfer, triangular resection with annuloplasty ring, and sliding leaflet valvuloplasty with annuloplasty ring.

• Common techniques for mitral valve repair for secondary MR include restrictive remodeling with a rigid annuloplasty ring, and chordal-sparing mitral valve replacement.

• A primary determinant of successful repair is the surgeon's experience. For asymptomatic (stage C1) patients, patients with complex mitral pathoanatomy, and patients who desire a minimally invasive or robotic approach to mitral valve repair, consider referral to an experienced mitral surgeon at a comprehensive valve center.

• Long-term follow-up of patients after surgical or transcatheter mitral intervention is essential for the assessment of durability, functional outcomes, and survival.

A 2018 meta-analysis comprising 12 retrospective studies from 5 electronic databases that included over 4200 patients compared mitral valve repair (n = 2950) versus replacement (n = 1252) for degenerative MR across all age groups. The investigators found that in terms of all-cause mortality and regardless of age, patients who underwent mitral valve repair had a lower risk of all-cause mortality, early mortality, and reoperation than those who underwent mitral valve replacement. ^[15] ​

In a separate 2018 report, mid-term clinical outcomes (7 years) data for isolated minimally invasive mitral valve (n = 960) repair versus chordal-sparing mitral valve replacement (n = 95) for degenerative MR suggest no significant difference between the two procedures. ^[16]

See also the Guidelines section for recommendations from major medical organizations for the management of MR.

Prehospital care

For the patient with acute mitral regurgitation (MR), the electrocardiogram should be examined closely for evidence of acute myocardial infarction (MI). If present, treatment with supplemental oxygen, analgesics for anginal chest pain, and sublingual nitrates for acute MI are the components of prehospital care. In the absence of acute MI, endocarditis should be excluded with blood cultures.

Transthoracic echocardiography should be performed.

Emergency department care

Any patient with acute or chronic mitral valve regurgitation with hemodynamic compromise should be evaluated for acute myocardial infarction. Consultations with specialists in cardiology and cardiothoracic surgery should be obtained early during patient stabilization.

Diuretic therapy is administered to individuals with pulmonary congestion, and an echocardiogram must be performed immediately. Patients with hemodynamic compromise should be expeditiously transferred to a cardiac critical care unit for central and pulmonary arterial pressure monitoring.

Medical therapy

Afterload-reducing agents (such as nitrates and antihypertensive drugs) and diuretics are helpful for maintaining the forward cardiac output in persons with MR with symptoms and/or LV dysfunction. Beta-blockers and biventricular pacing are used for primary treatment of LV dysfunction in functional MR.

Intra-aortic balloon counterpulsation should be considered in the patient with acute MR and hemodynamic compromise.

If atrial fibrillation is encountered, maintenance of a normal ventricular response with beta-blockers, calcium channel blockers, and/or digitalis therapy is considered.

Anticoagulation is considered for patients who develop atrial fibrillation or have had mitral valve replacement surgery.

A study using data from the Mitral Regurgitation International Database (MIDA) found that patients with severe MR without a class I indication for surgical intervention fared significantly better when they were treated with surgery than when they underwent “watchful waiting” while being treated with medical therapy. The survival differences were statistically significant, and the results were confirmed in propensity score-matched and inverse-probability–weighted analyses. ^{[9, 10, 13]}

In addition to maintaining good oral hygiene, antibiotics are recommended prior to any dental procedure that involves manipulation of gingival tissue, the periapical region of a tooth, or perforation of oral mucosa in patients with any of the following conditions ^[8] :

• Prosthetic heart valve
• Previous infectious endocarditis
• Some forms of congenital heart disease
• Valvulopathy in a cardiac transplant recipient

Inotropic agents should be considered in chronic severely symptomatic MR, and consultation with a specialist in cardiothoracic surgery should be obtained.

Diet and activity

A diet low in sodium is indicated for patients with symptomatic chronic MR or those with LV dysfunction.

Asymptomatic patients with MR of any severity can exercise without restriction if all of the following criteria are met:

• Sinus rhythm
• Normal LV and left atrial dimensions
• Normal pulmonary artery pressure

Invasive management

Surgery is recommended for moderate to severe (grade >3) mitral regurgitation (MR) in symptomatic patients or those with left ventricular (LV) dysfunction. ^[17]

The risks and benefits of surgery should be assessed based on the age and comorbidity of each individual patient, with the decision to proceed or not to proceed being grounded in uniformly accepted guidelines. Consider the following:

• Operative mortality is higher in the patients older than 75 years.
• Coronary artery disease and other valvular diseases are prevalent in older patients who often require concomitant coronary artery bypass surgery, further increasing operative risk.
• Outcomes are worse in patients with severe MR and marked LV dysfunction.
• As outcomes are worse in patients with severe MR and pulmonary hypertension (pulmonary artery systolic pressure >50 mm Hg), surgical referral is advised prior to development of pulmonary hypertension. ^{[14, 18, 19]}
• Right ventricular dysfunction is associated with worse survival of functional MR and LV dysfunction in patients undergoing MitraClip in association with no response to N-terminal pro-B-type natriuretic peptide (NT-proBNP). ^[20]

In a retrospective study of 121 patients with significant chronic ischemic mitral regurgitation, intervention with mitral valve replacement was associated with improved postoperative exercise hemodynamic performance and long-term functional capacity compared with mitral valve annuloplasty. ^[21]

• Asymptomatic patients with preserved LV function and new onset atrial fibrillation or pulmonary hypertension (Class IIa)
• Asymptomatic patients with preserved LV function and a high likelihood of durable repair, low surgical risk and flail leaflet, and LV end-systolic dimension of 40 mm or greater (Class IIa)
• Patients with severe LV dysfunction refractory to medical therapy with a high likelihood of durable repair and low comorbidity (Class IIa)

Surgery may be considered in the following situations:

• Patients with severe LV dysfunction refractory to medical therapy with low likelihood of durable repair and low comorbidity (Class IIb)
• Asymptomatic patients with preserved LV function, high likelihood of durable repair, low surgical risk, and either left atrial dilatation and sinus rhythym or pulmonary hypertension on exercise

Percutaneous treatment of mitral regurgitation

In October 2013, the FDA approved the MitraClip valve repair system for patients with symptomatic degenerative MR with a prohibitive risk for mitral-valve surgery. ^{[2, 3]} Approval was based on registry data and the Endovascular Valve Edge-to-Edge Repair Study (EVEREST II), in which percutaneous repair of the mitral valve was less effective in reducing MR but was associated with similar improvement in clinical outcomes and with superior safety. ^{[2, 3]}

Various percutaneous strategies for treatment of MR are also under investigation. ^[22]

Double-orifice mitral valve repair using an implanted device that grasps and approximates the edges of the mitral valve leaflets at the origin of the regurgitant jet has been compared with mitral valve surgery for patients with 3+ to 4+ MR in a randomized trial. ^[23] At 12 months, the primary combined endpoint of survival, surgery for mitral valve dysfunction, and grade 3+ to 4+ MR was met in 55% of patients randomized to percutaneous repair and 73% of patients in the surgical group (p = 0.007). Major adverse events at 30 days occurred in 27% of patients who underwent percutaneous repair and 45% of patients who underwent surgery (p < 0.001). When transfusions were excluded from the safety analysis, no statistically significant difference in major adverse events was found between the groups. ^[23]

At 12 months, 20% of the percutaneous repair group required surgery for mitral valve dysfunction (p< 0.001) compared with 2.2% of the surgery group. ^[23] At 12 months, 19% of the percutaneous repair group had residual3+ or 4+ MR compared with 6% of the surgery group. Patients in the surgical group had greater improvement in ejection fraction than those in the percutaneous repair group (p = 0.005). Physical quality of life at 30 days was worse in the surgical group (p < 0.001); however, at 12 months, no significant difference was found. ^[23]

Percutaneous double-orifice mitral valve repair appears safer than surgery, primarily due to reduced risk of transfusion. Although surgery results in more favorable reduction of MR, quality of life at one year is similar for both approaches. Surgical mitral valve repair remains the criterion standard intervention for severe MR; however, percutaneous double-orifice repair is a viable alternative for patients at high risk for surgery.

In a retrospective study (1990-2009) of data from 4989 patients with significant coronary artery disease who were treated for moderate or severe ischemic mitral regurgitation, intervention with coronary artery bypass grafting (CABG) alone was associated with the lowest mortality. ^[24] CABG with or without mitral valve surgery was associated with a lower mortality than for either percutaneous coronary intervention or medical treatment alone. ^[24]

In a retrospective study (2001-2015) comprising 61 patients with LV aneurysm and ischemic MR, concomitant CABG, LV restoration, and MV repair was effective, with 95.1% 1-year survival rates, 86.9% 5-year survival rates, and  80.3% 10-year survival rates. ^[25]

The 5-year results from the EVEREST II (Endovascular Valve Edge-to-Edge Repair Study) that compared percutaneous mitral valve repair with the MitraClip device with conventional mitral valve surgery revealed increased rates of grade 3+ and 4+ mitral regurgitation (12.3%) and surgery (27.9%) with percutaneous repair than with conventional repair (1.8% and 8.9%, respectively). ^[26] The majority of surgery following percutaneous repair (78%) occured within the first 6 months. The 5-year mortality was similar between the two groups: 20.8% for percutaneous repair and 26.8% for conventional surgery. ^[26]

In a case series of 4 patients who underwent MitraClip therapy for recurrent MR during the early phase after the initial procedure, for which partial clip detachment was the suspected cause, additional clip(s) stabilized the partially detached clips and improved the MR grade. ^[27]  However, the investigators cautioned that patients with partial clip detachment and paracommissural MR may not be good candidates for repeat MitraClip.

Medical complications of mitral regurgitation (MR) may include the following:

• Pulmonary edema
• Congestive heart failure
• Irreversible left ventricular (LV) systolic dysfunction
• Thromboembolism resulting from atrial fibrillation

Surgical complications may include the following:

• Operative risks include infection, bleeding, intraoperative myocardial infarction, and stroke.
• In young patients, bioprosthetic valves (ie, porcine valves) have a propensity for early degeneration due to calcification.
• Mechanical valve complications include prosthetic valve dysfunction and valve thrombosis with or without embolism, particularly in the patient who is not adequately anticoagulated.
• Hemolysis may occur in the patient with a ball and cage mechanical valve because of mechanical valve destruction of circulating red blood cells. Hemolysis in the patient with a tilting disk valve usually indicates the presence of a perivalvular leak.
• Thromboembolism in patients with mechanical valves who are on anticoagulation therapy occurs at a rate of 1-3% per year.
• In the absence of anticoagulation, thromboembolism occurs at a rate of approximately 1.5% per year with a porcine valve.
• Prosthetic valve infection may occur in bioprosthetic or mechanical valves.