Approach Considerations
The definitive treatment of mitral regurgitation remains surgery, of which the two primary surgeries are mitral valve replacement and mitral valve repair. The risk-benefit ratio must be examined carefully with each individual situation prior to a decision to replace the valve.
If mitral regurgitation is treated early enough, mitral valve repair is the optimal choice (lower risk of infectious endocarditis and better postoperative left ventricular function).
Repair is usually available only to those whose condition has a nonrheumatic, noninfectious, and nonischemic cause; therefore, candidates for mitral valve repair are few.
Valve replacement should not be undertaken in asymptomatic patients.
Early recognition of even minimal symptoms is crucial in attempting to preserve as much left ventricular function as possible.
Chordal transection during replacement surgery results in some impairment of left ventricle function; thus, the more left ventricular function prior to surgery, the better the outcome.
See also the Guidelines section for management and intervention recommendations from the American College of Cardiology/American Heart Association (ACC/AHA) (2014, 2017), [4, 5] American Association for Thoracic Surgery (2016), [6] and, European Society of Cardiology/European Association for Cardio-Thoracic Surgery (ESC/EACTS) (2017). [7]
Emergency Department Care
Acute mitral regurgitation is a specific case in which immediate intervention in the emergency department can make a difference. However, early involvement of cardiology and cardiac surgery teams is essential.
If the etiology is myocardial infarction, and immediate percutaneous coronary intervention (PCI) is not available, infusion of thrombolytics may reestablish blood flow to the papillary muscle, possibly restoring function.
The mainstay of medical treatment in most other cases of mitral regurgitation is afterload reduction. Afterload reduction decreases the impedance to left ventricular ejection and, as a result, decreases the regurgitant volume. Administering arterial vasodilators (eg, sodium nitroprusside) may reduce aortic impedance to help raise aortic outflow while decreasing regurgitation. [8] However, the use of these agents may be limited in the setting of cardiac output and hypotension; in such cases, afterload reduction and decreased regurgitant flow may be achieved with aortic balloon counterpulsation while augmenting mean arterial blood pressure. Most often, urgent mitral valve repair is required for restoration of normal circulation. [8]
The treatment of pulmonary edema should include oxygen, diuretics, nitrates, and early intubation if respiratory failure results.
These individuals can benefit from afterload reduction with nitroprusside, even in the setting of a normal blood pressure.
Do not attempt to alleviate tachycardia with beta-blockers. Mild-to-moderate tachycardia is beneficial in these patients because it allows less time for the heart to have backfill, which lowers regurgitant volume.
Rapid atrial fibrillation secondary to chronic mitral regurgitation may be controlled with diltiazem or, less commonly, digoxin. Patients with severe heart failure or hypotension should not be treated with diltiazem.
The physician should consider cardioversion in refractory or unstable patients. If cardioversion is effective, however, the restored sinus rhythm usually is transient due to the left atrium being severely dilated.
Consultations
In the setting of acute mitral regurgitation secondary to an acute myocardial infarction, a cardiologist should be involved early. Point-of-care ultrasonography (POCUS) may reveal a hyperdynamic left ventricle or wall motion abnormalities; however, standard echocardiography is typically necessary to identify papillary muscle rupture. Interventional cardiology for emergent cardiac catheterization and intervention, as an alternative to thrombolysis, should be obtained as per protocol in institutions with such capability.
For highly suspicious cases, a cardiothoracic surgeon should be notified as soon as possible, even before echocardiography is performed. This will allow the surgical team to mobilize. Placement of an intraaortic balloon pump or a percutaneous left ventricular assist device may stabilize a patient prior to surgery.
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Acute mitral regurgitation. Transesophageal echocardiogram demonstrating prolapse of both mitral valve leaflets during systole.
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Acute mitral regurgitation. Transthoracic echocardiogram demonstrating bioprosthetic mitral valve dehiscence with paravalvular regurgitation.
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Acute mitral regurgitation. Severe mitral regurgitation as depicted with color Doppler echocardiography.
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Acute mitral regurgitation. Four-chamber apical view of a two-dimensional transthoracic echocardiogram demonstrates mitral valve prolapse (MVP), a common cause of mitral regurgitation.
