Mitral valve stenosis

Disease Description (Causes and Symptoms)

• Definition summary: Mitral stenosis is a condition in which the mitral valve between the left atrium and left ventricle becomes narrowed, restricting blood flow and increasing left atrial pressure.
• Main causes: Most cases are sequelae of rheumatic fever (rheumatic mitral stenosis); less commonly, congenital malformations, degenerative calcification, post-radiation changes, and infectious diseases may be causes.
• Pathophysiology summary: Decreased valve orifice area → increased left atrial pressure → increased pulmonary venous pressure → pulmonary congestion, pulmonary edema, and pulmonary hypertension → increased burden on the right heart. Left atrial enlargement increases the risk of atrial fibrillation and the risk of left atrial thrombus formation and embolism.
• Main symptoms: Dyspnea on exertion (early), gradually progressing to dyspnea at rest, paroxysmal nocturnal dyspnea, cough (with sputum, sometimes blood-streaked sputum/hemoptysis), chest pain, fatigue, palpitations (atrial fibrillation), syncope or dizziness (in severe cases).
• Examination findings: Heart sounds associated with left atrial enlargement (opening snap + palpable murmur — pansystolic expansion sound/low-pitched diastolic murmur).
• Key diagnostic tests: Transthoracic echocardiography is used to assess valve area, mean pressure gradient, and valve morphology (calcification and flexibility); transesophageal echocardiography (TEE) is useful for evaluating left atrial thrombus. Electrocardiography (left atrial enlargement, atrial fibrillation), chest X-ray (left atrial enlargement, pulmonary venous congestion).

Treatment Methods and Precautions

• Conservative (medication) treatment
  • Diuretics to relieve symptoms (control pulmonary congestion)
  • Heart rate control: If atrial fibrillation is present, beta-blockers, calcium channel blockers (verapamil/diazepam not), or digoxin may be used for tachycardia-related atrioventricular block (heart rate control)
  • Anticoagulation: If atrial fibrillation is present or the risk of left atrial thrombus is high, anticoagulants such as warfarin (or NOACs according to the indication) are recommended. TEE is needed to check for thrombus before starting anticoagulation.
  • Supportive treatment such as oxygen therapy according to heart failure and hypoxic status
• Interventional/surgical treatment (determined according to symptoms or functional severity)
  • Percutaneous mitral balloon commissurotomy (PMBC)
    • Indications: Preferentially considered for rheumatic stenosis when valve calcification and adhesion are mild and there is no left atrial thrombus.
    • Advantages: Performed through the femoral vein without a skin incision, with rapid recovery (usually 1–2 days) and immediate symptom improvement.
    • Disadvantages: Restenosis may occur (regular echocardiographic follow-up is required), and the procedure may not be possible depending on valve anatomy.
  • Surgical treatment
    • Commissurotomy through thoracotomy (open surgical valvuloplasty) — when the valve structure can be preserved
    • Mitral valve replacement — when the valve is severely damaged or balloon valvotomy/valvuloplasty is not possible
      • Mechanical valve: Highly durable, but lifelong anticoagulation (warfarin) is required
      • Tissue valve (bioprosthetic valve): Anticoagulation is not required (or is required only for a short period), but its lifespan is shorter than that of a mechanical valve, increasing the possibility of repeat surgery in younger patients
• Pregnancy-related management: Symptoms may worsen during pregnancy due to increased fluid volume — consultation with a cardiologist is necessary when planning a pregnancy. Discuss treatment options (balloon valvotomy, surgery, and medication) and anticoagulation management (fetal risks of warfarin, conversion to LMWH, etc.) with a specialist.
• Complication management and precautions
  • Prevention of embolism (stroke) caused by atrial fibrillation and left atrial thrombus
  • Infective endocarditis: Under current guidelines, broad prophylactic antibiotics are not recommended solely for mitral stenosis itself (they apply only to certain high-risk groups) — consult the attending physician regarding dental procedures and other procedures.
  • Management of bleeding risk while taking anticoagulants (report immediately if bleeding symptoms occur)
• Follow-up tests: Regular echocardiography (valve area, mean pressure gradient, pulmonary artery pressure), INR monitoring (for mechanical valves or anticoagulation), and prompt evaluation if symptoms change

Checklist Before an Outpatient Visit (Items to Prepare and Example Questions)

• Items to prepare/bring
  • All medications currently being taken (actual medications, prescriptions, or a list) — if taking an anticoagulant (warfarin), bring recent INR records
  • Previous test results: Recent echocardiography report (valve area, mean pressure gradient, valve morphology evaluation), electrocardiogram/chest X-ray results
  • Symptom diary: When dyspnea began and situations in which it worsens (exercise, lying down), nighttime symptoms, cough (including blood-streaked sputum), and the degree of limitation in indoor and outdoor activities (e.g., organized according to the NYHA classification)
  • Medical history: History of rheumatic fever, history of previous cardiac surgery/procedures, pregnancy history (for women), bleeding tendency/history of bleeding
  • Changes in body weight, leg swelling, syncope or presyncope symptoms
• Information to tell the doctor in advance at the outpatient visit (examples)
  • Medications started recently (including anticoagulants and antiplatelet agents)
  • Pregnancy plans or whether you are currently pregnant
  • Bleeding (nosebleeds, bleeding gums, blood in the urine, etc.) or severe bruising
  • Whether left atrial thrombus was present on a previous echocardiogram

General Example Questions to Ask the Doctor

• How severe is my valve stenosis (valve area, mean pressure gradient, and pulmonary artery pressure)? When will an intervention or surgery be necessary?
• Is percutaneous balloon valvotomy possible for me? If so, what are the expected benefits and the likelihood of recurrence?
• If surgery (valve replacement) is needed, which do you recommend: a mechanical valve or a bioprosthetic valve? What are the advantages and disadvantages of each?
• Do I need anticoagulants? If so, which medication should I take and for how long? What should I do if bleeding occurs?
• I am planning a pregnancy—is it safe? What management will be needed before, during, and after pregnancy?

Examples of Disease-Specific Questions

• How are valve morphology (flexibility and calcification) and the Wilkins score (or valve score) shown on my echocardiogram? Based on the results, am I eligible for percutaneous balloon valvotomy?
• I currently have atrial fibrillation. Do I absolutely need to take an anticoagulant? What are the recommendations when no left atrial thrombus is found? (Especially if planning a pregnancy, what are the options for and methods of managing anticoagulation?)