SUMMARY: 

Mitral regurgitation (MR) of either primary or secondary cause is the most prevalent valvular disorder in the United States increasing in prevalence with advanced age. The 2020 ACC/AHA Guidelines for the Management of Patients with Valvular Heart Disease provides a contemporary and comprehensive review of treating this condition. 

• Causes of MR 
• Signs and Symptoms  
• Diagnosis and Follow-Up 
• Stages of MR 
• Exercise testing in patients  
• Medical Therapy  
• Prevention of Rheumatic Heart Disease and Secondary Rheumatic fever  
• Procedural Interventions  
• Antiplatelet/Anticoagulant therapy post MVR 

Causes Of Mitral Regurgitation 

• Acute MR 
  • Disruption of different parts of the mitral valve apparatus such as from infective endocarditis|, spontaneous chordal rupture|papillary muscle rupture 
  • May present with hemodynamic instability e.g., hypoxia | dyspnea due to pulmonary edema 
• Chronic MR 
  • Primary MR (degenerative): Disease of mitral valve apparatus (i.e. Rheumatic heart disease| mitral valve prolapse|myxomatous valve degeneration) 
  • Secondary MR (functional): Due to left atrium or left ventricular dilatation typically from systolic dysfunction 

Signs And Symptoms  

• Symptoms 
  • Exertional dyspnea | Decrease exercise tolerance | Heart failure symptoms 
• Physical exam signs 
  • Systolic murmur | Extra heart sound (S3) | Cardiac impulse is brisk and hyperdynamic 

Diagnosis and Follow-Up 

• Transthoracic echocardiogram (TTE) is indicated in patients with signs and symptoms of MR 
• Patients with MR  
  • When TTE does not provide sufficient information, a transesophageal echocardiogram (TEE) is indicated to evaluate MR severity and to guide mitral valve interventions intraoperatively 
  • Cardiac MRI is indicated to assess LV/RV volumes, function and assess MR severity if discrepant findings on clinical assessment and echocardiography 

Frequency Of TTE in Asymptomatic Patients With MR 

• Mild severity: Every 3 to 5 years 
• Moderate severity: Every 1 to 2 years 
• Severe: Every 6 months to 1 year (more frequently with dilating LV) 

Stages of MR 

• Stage A: At risk of MR: Mild mitral valve prolapse or mild valve thickening  
• Stage B: Progressive MS: Mild to moderate MR 
• Stage C: Asymptomatic Severe MR 
• Stage D: Symptomatic Severe MR 

Exercise Testing  

• In patients with primary MR with symptoms that may be attributable to MR 
  • Hemodynamic exercise testing with echocardiography or invasive assessment is reasonable to correlate severity of MR with patient’s exertional symptoms 

Medical Therapy 

• Acute MR 
  • Vasodilators | Mechanical support devices (i.e., intra-aortic balloon pump) 
• Chronic MR 
  • Primary: Vasodilators for blood pressure control. No indication if patient is normotensive. 
  • Secondary: Heart failure guideline directed medical therapy (GDMT) due to LV systolic dysfunction. 

Prevention of Rheumatic Heart Disease and Secondary Rheumatic Fever 

• Prompt treatment of Group A Strep infections i.e., impetigo or tonsillar pharyngitis with antibiotics decreases the changes of developing rheumatic valve disease by 70% 
• In patients that do develop rheumatic valve disease, secondary prevention of rheumatic fever is indicated typically with penicillin 
• Duration for secondary prophylaxis for Rheumatic Fever depends on presence/absence of carditis during acute rheumatic fever and development of persistent valvular disease post-acute phase 
• Carditis: Valvulitis (Manifested early as mitral regurgitation with/without aortic regurgitation). Myocarditis or pericarditis can also be seen 
• Rheumatic fever with carditis and persistent valvular heart disease 
  • 10 years or until patient is 40 years of age (whichever is longer) 
• Rheumatic fever with carditis and no valvular disease 
  • 10 years or until patient is 21 years of age (whichever is longer) 
• Rheumatic fever without carditis 
  • 5 years or until patient is 21 years of age (whichever is longer) 

Procedural Interventions  

Acute MR 

• Prompt mitral valve surgery, preferably mitral valve repair 

Chronic MR 

• Primary MR 
  • Symptomatic with severe primary MR: MV intervention is recommended irrespective of LV systolic function 
  • Asymptomatic with severe primary MR and LV systolic dysfunction (LVEF ≤ 60%, LV end systolic diameter ≥ 40 mm): MV surgery is recommended 
  • Severe primary MR where surgery is indicated: MV repair should be performed if feasible over mitral valve replacement 
  • Asymptomatic patients with primary severe MR with normal LV systolic function ≥ 60% and LV end systolic diameter ≤ 40 mm: MV repair is reasonable  
  • Symptomatic severe MR: Transcatheter edge-to-edge repair (TEER) (mitral clip) is reasonable if patient has high or prohibitive surgical risk 
• Secondary MR 
  • Symptomatic patients with severe MR related to LV systolic dysfunction (LVEF <50%) with persistent symptoms despite GDMT: Transcatheter edge-to-edge repair (TEER) (mitral clip) is reasonable if LVEF 20-50%, LV end systolic diameter ≤ 70 mm pulmonary artery systolic pressure ≤ 70 mmHg. 
  • If undergoing CABG for CAD/ischemia, mitral valve surgery is reasonable if patient with concomitant severe secondary MR 

Antiplatelet/Anticoagulant Therapy Post MVR 

Decision between a bioprosthetic vs mechanical mitral valve should consider patient’s values, preferences, co-morbid conditions, and risks of anticoagulant therapy 

• Bioprosthetic MVR 
  • Daily low-dose aspirin is recommended lifelong in addition to VKA anticoagulation with INR goal of 2.5 for first 3 to 6 months 
• Patients with a mechanical MVR 
  • Anticoagulation ONLY with vitamin K antagonist (VKA) is recommended with an INR goal of 3 

NOTE: DOACs (Direct Oral Anticoagulants) are currently not recommended after mitral valve replacement out of concern for increased risk of clot development  

LEARN MORE-PRIMARY SOURCES: 

ACC/AHA 2020: Guidelines for the management of patients with Valvular Heart DIsease  

Primary Prevention of Rheumatic Heart Disease 

Burden of valvular heart diseases: a population-based study