Mitral valve insufficiency

Disease Description (Causes and Symptoms)

• Definition/Pathophysiology: Mitral regurgitation (insufficiency) is a condition in which the mitral valve does not close completely during left ventricular contraction, causing blood to flow backward from the left ventricle into the left atrium. Clinical manifestations differ between acute cases (e.g., chordal rupture or myocardial infarction-related cases) and chronic cases (valvular degeneration, rheumatic disease, ischemic causes, etc.). In chronic cases, left atrial enlargement and compensatory changes develop, and as the condition progresses, it may lead to impaired left ventricular function.
• Main causes: Rheumatic valvular disease (historical prevalence), mitral valve prolapse (myxomatous degeneration), chordal rupture, myocardial infarction and cardiomyopathy (ischemic or functional MR), infective endocarditis, congenital abnormalities, cardiac tumors, etc.
• Main symptoms: Shortness of breath during exertion (and, as the condition progresses, shortness of breath at rest), fatigue, easy fatigability, cough and sputum, orthopnea/paroxysmal nocturnal dyspnea, chest pain (when accompanied), and, in acute severe cases, possible pulmonary edema and acute respiratory distress.

Treatment Methods and Precautions

• General principles
  • Treatment strategies differ depending on the cause (primary valvular disease vs. functional/secondary MR).
  • Indications for surgery or intervention are determined based on the presence or absence of symptoms, the severity of MR, left ventricular size and contractility (LVEF and LVESD), pulmonary artery pressure, and whether atrial fibrillation has developed.
• Drug treatment (supportive and symptom relief)
  • In chronic functional MR, attempts are made to reduce the burden on the left ventricle with standard heart failure treatment (ACE inhibitors/ARBs/ARNI, beta-blockers, MRAs, SGLT2 inhibitors, etc.).
  • Symptoms may be relieved with diuretics (to control edema and pulmonary congestion) and blood pressure control (including vasodilators).
  • In acute severe MR, hemodynamic stabilization (diuretics, vasodilators, and inotropes if needed) and prompt surgical treatment should be considered.
• Procedures/Surgery
  • Mitral valve repair: Recommended as the first choice when possible (preservation of cardiac function; anticoagulation is often not required).
  • Mitral valve replacement: Used when repair is impossible or insufficient. Mechanical valves (requiring lifelong anticoagulation) and tissue valves (a shorter mandatory anticoagulation period but limited durability).
  • Percutaneous valve procedures: MitraClip (transcatheter edge-to-edge repair) and similar procedures may be considered in patients at high surgical risk; patient selection is important for determining the indications and effectiveness (e.g., the criteria of the COAPT study).
  • Ischemic (functional) MR: First improve left ventricular function (with medication, cardiac resynchronization, etc.), then consider intervention; in selected patients, percutaneous repair may improve symptoms and prognosis.
• Indications for surgery (general criteria; individualization required)
  • Symptomatic severe primary MR: Surgery is recommended.
  • In asymptomatic severe primary MR, surgery is recommended when there is reduced left ventricular function (LVEF ≤60% or LVESD ≥40 mm), newly developed atrial fibrillation, a resting pulmonary artery systolic pressure >50 mmHg, etc.
  • For secondary (functional) MR, surgery or intervention is determined through multidisciplinary discussion when symptoms and regurgitation remain after treatment of the underlying cardiomyopathy.
• Follow-up and testing
  • Regular echocardiography (customized, such as every 3–6 months for severe disease and every 6–12 months for mild-to-moderate disease) and monitoring of clinical symptoms.
• Precautions/Risk of complications
  • Acute severe MR is an emergency condition (pulmonary edema and hypotension), and delaying supportive treatment carries a risk of death.
  • When an artificial valve is used, especially a mechanical valve, lifelong anticoagulation (warfarin) is required → management of bleeding risk and drug interactions is necessary.
  • Risk of infective endocarditis (especially in people with artificial valves) — preventive antibiotics are recommended in some situations (see guidelines).
  • Delaying the timing of surgery may cause irreversible left ventricular damage and result in a poor prognosis.

Checklist Before an Outpatient Visit (Examples of Items to Bring, Tests, and Records)

• Items to bring and materials that can be submitted
  • A list of medications currently being taken (including doses and times of administration)
  • Previous test and surgical records: recent echocardiography (if possible, both the report and images), electrocardiogram (ECG), chest X-ray, blood test results, and INR values (when taking anticoagulants)
  • Symptom records: shortness of breath (changes over time and NYHA classification according to exertion level), cough and sleep disturbance (nocturnal dyspnea/orthopnea), whether edema has occurred, and circumstances in which chest pain occurs
  • Risk factors/medical history: previous rheumatic fever, myocardial infarction, endocarditis, hypertension, diabetes, etc.
• Key items the doctor may check during the outpatient visit (examples)
  • When symptoms began and how quickly they progressed (acute vs. chronic)
  • Degree of shortness of breath during activity (whether daily activities are limited)
  • Bleeding, bruising, and medication adherence (especially anticoagulants)
  • Recent weight changes (a rapid short-term increase suggests fluid retention)

Examples of General Questions to Ask the Doctor

• "What is the severity of my current mitral regurgitation, and how is my left ventricular function (LVEF, LVESD)?"
• "What are the criteria for determining that surgery is needed even if I have no symptoms?"
• "What are the expected benefits and risks (complications) of the recommended treatment (surgery/procedure/medication)?"
• "If I need to take an anticoagulant, how should it be managed (target INR and what to do in the event of bleeding)?"
• "Are there any special precautions I should take regarding lifestyle (diet, exercise, pregnancy, and travel)?"

Examples of Disease-Specific Questions

• "In my case, is mitral valve repair possible, and what is the repair success rate (and the possibility of repeat surgery)?"
• "Do I meet the indications for percutaneous repair such as MitraClip, and what are the advantages and disadvantages compared with surgical treatment?"
• (Regarding anticoagulation) "If a mechanical valve is recommended, what alternatives are available if I am planning a pregnancy? What are the guidelines for managing anticoagulation during pregnancy?"

(Note: The information above is general medical information. The diagnosis and treatment of individual patients should be decided in consultation with their healthcare providers.)