What is the best course of treatment for a patient presenting with acute mitral valve incontinence?

Acute Mitral Valve Regurgitation Management

Prompt mitral valve surgery is the definitive treatment for acute severe mitral regurgitation, with medical therapy and mechanical circulatory support serving only as temporizing measures to stabilize the patient until emergency operation can be performed. 1, 2

Immediate Diagnostic Approach

Clinical Recognition

• Suspect acute MR when sudden hemodynamic deterioration occurs with pulmonary edema and/or cardiogenic shock, typically 2-7 days post-MI but most mechanical complications occur within 24 hours 2
• The systolic murmur may be soft, short, or completely absent due to rapid equalization of LV and left atrial pressures—do not rely on auscultation alone to exclude the diagnosis 1, 2
• Look for a hyperdynamic left ventricle rather than depressed LV function, which distinguishes acute MR from other causes of hemodynamic collapse 1

Echocardiographic Evaluation

• Transthoracic echocardiography (TTE) is the first-line diagnostic test to identify valve disruption, chordal rupture, papillary muscle rupture, or leaflet perforation from endocarditis 1
• Transesophageal echocardiography (TEE) is mandatory when TTE is nondiagnostic but clinical suspicion remains high, as narrow eccentric jets, tachycardia, and pressure equalization can make TTE unreliable 1
• TEE is especially critical for detecting vegetations, annular abscesses, and visualizing the ruptured papillary muscle stump using transgastric views 1, 2

Hemodynamic Monitoring

• Insert pulmonary artery catheter to guide management—look for large V-waves in pulmonary capillary wedge pressure tracing, though these are present in only 33% of cases 2, 3
• Right ventricular filling pressure is typically normal (82% of cases), while pulmonary artery and capillary pressures are elevated (95% of cases) 3

Immediate Stabilization (Temporizing Only)

Mechanical Circulatory Support

• Insert intra-aortic balloon pump (IABP) immediately for temporary circulatory support while arranging surgery 1, 2
• IABP reduces afterload, decreases regurgitant volume, and improves coronary perfusion by lowering systolic aortic pressure while increasing diastolic pressure 1, 2
• Percutaneous circulatory assist devices may also be effective for stabilization before operation 1

Pharmacologic Management

• Vasodilators (sodium nitroprusside or nicardipine) reduce impedance to aortic flow, preferentially directing flow forward rather than into the regurgitant pathway 1
• Nitroprusside can reduce peripheral vascular resistance from 1480 to 702 dyn·sec·cm⁻⁵ with proportionate reduction in regurgitant fraction 3
• Use is often limited by systemic hypotension that worsens when peripheral resistance is decreased 1
• Inotropic agents (dobutamine 2-20 mcg/kg/min) should be added if systolic blood pressure is 70-100 mmHg 1, 2
• Diuretics (furosemide 0.5-1.0 mg/kg IV) for pulmonary congestion 1, 2
• Nitrates reduce filling pressures in acute MR 1

Definitive Surgical Management

Timing and Indications

• Obtain immediate surgical consultation when acute severe MR is confirmed—this is a surgical emergency 1, 2
• Operate emergently without delay for medical optimization, as rupture can extend abruptly causing sudden collapse even in hemodynamically stable patients 2
• Surgery should proceed even if temporary stabilization is achieved, as medical therapy alone carries near 100% mortality 2
• Three of 42 patients (7%) died before intended emergency surgery could be performed 3

Surgical Technique

• Mitral valve replacement, not repair, is required for papillary muscle rupture due to extensive tissue necrosis precluding reliable repair 2
• Perform concomitant CABG at the time of valve surgery to address the culprit coronary lesion in ischemic cases 2
• For chordal rupture without muscle necrosis, mitral repair is usually feasible 1
• If infective endocarditis is the cause, antibiotic administration must accompany early surgery 1

Surgical Outcomes

• Emergency surgery carries 20-46% mortality but is vastly superior to medical therapy alone 2
• Early mortality for emergency surgery was 23.8% versus 7.7% for elective surgery within one year in one series 3
• Five-year survival after successful surgery averages 60-70% 2

Critical Pitfalls to Avoid

• Do not dismiss the diagnosis based on absence of murmur—severe acute MR may be silent due to pressure equalization 1, 2
• Do not delay surgery for "medical optimization" in confirmed rupture—temporizing measures are only to stabilize for immediate operation 2
• Do not attempt mitral valve repair in acute papillary muscle rupture—replacement is required due to extensive tissue necrosis 2
• Do not forget CABG—revascularization must accompany valve surgery in ischemic cases 2
• Do not rely on bedside hemodynamic monitoring alone for differential diagnosis or quantitative assessment, as it is unreliable (V-waves present in only 33% of cases) 3

Special Considerations by Etiology

Post-Myocardial Infarction

• The posteriomedial papillary muscle has singular blood supply from the right coronary or circumflex artery, making it vulnerable to inferior MI 2
• Complete papillary muscle rupture causes torrential MR that is poorly tolerated and requires immediate surgery 1
• Even partial papillary muscle rupture with hemodynamic stability requires urgent surgery as it can suddenly progress to complete rupture 1

Infective Endocarditis

• TEE is essential for detecting vegetations and annular abscesses that accentuate the need for urgent surgical approach 1
• Therapy must include antibiotic administration combined with early surgery 1

Ischemic Dysfunction Without Rupture

• If ischemia causes dysfunction without structural rupture, consider revascularization alone initially, as CABG may improve LV function and reduce MR 2
• Concomitant mitral annuloplasty with undersized ring is often beneficial even with moderate MR at time of CABG 2

Contraindications to Surgery

• Age alone is not a contraindication—consider comorbidities, functional status, and patient wishes 2
• Surgery should be considered futile only when patient directives or severe comorbidities preclude benefit 2