Aortic valve stenosis

Disease Description (Causes and Symptoms)

• Definition summary: Aortic valve stenosis is a condition in which the aortic valve located in the passage through which blood exits from the left ventricle into the aorta does not open sufficiently, narrowing the left ventricular outflow tract. This causes increased left ventricular pressure, left ventricular hypertrophy, and reduced systemic blood flow.
• Main causes
  • Degenerative (calcification due to aging) — most common
  • Congenital bicuspid aortic valve
  • Rheumatic valvular disease (previous rheumatic fever)
  • Valvular damage caused by infective endocarditis
• Pathophysiology summary: Stenosis of the valvular outflow tract → increased left ventricular systolic pressure overload → left ventricular hypertrophy (LVH) and impaired diastolic function, reduced cardiac output → as stenosis progresses, chest pain (exertional ischemia), syncope (insufficient blood flow during exercise), dyspnea (a symptom of heart failure), etc. may occur
• Main symptoms
  • May be asymptomatic (mild to moderate)
  • Once symptoms develop, the prognosis worsens rapidly: chest pain (exertional angina), syncope (exertional syncope), dyspnea (heart failure), fatigue, cough and sputum, autonomic dysfunction, etc.
  • Clinical natural history (average survival after symptoms [standard examples]): approximately 5 years after the onset of chest pain, approximately 3 years after the onset of syncope, and approximately 2 years after the onset of dyspnea (heart failure) (treatment is needed when symptoms develop)

Treatment Methods

• General principles: Medication cannot fundamentally improve the condition, and valve replacement (or an interventional procedure) is the standard treatment for severe symptomatic aortic valve stenosis.
• Diagnosis and severity assessment
  • Basic: Transthoracic echocardiography (TTE) + Doppler — assessment of valve area, mean gradient, and peak velocity
  • Criteria for severe stenosis (examples from general guidelines): valve area < 1.0 cm², mean gradient ≥ 40 mmHg, or peak velocity ≥ 4.0 m/s
  • Additional tests when necessary: transesophageal echocardiography (TEE), cardiac CT (especially valve and annulus measurements before TAVI), cardiac catheterization (coronary artery assessment), BNP, ECG, and chest X-ray
• Surgical treatment
  • Surgical aortic valve replacement (AVR): insertion of a mechanical valve or bioprosthetic (tissue) valve through open-heart surgery
    • Mechanical valve: excellent durability, but lifelong anticoagulation (warfarin) is required
    • Bioprosthetic (tissue) valve: less burden from anticoagulation (but limited durability)
• Percutaneous treatment
  • Transcatheter aortic valve implantation (TAVI/TAVR): insertion of a bioprosthetic valve through a transfemoral or transapical approach in patients at high surgical risk. Indications have recently expanded (moderate- to high-risk groups and selected cases).
• Drug treatment (for supportive care and symptom relief)
  • Limited use of diuretics and other medications to control heart failure symptoms
  • Blood pressure control (when necessary) — vasodilators should be used cautiously because they may cause hypotension
  • Beta-blockers, nitroglycerin, and other medications for relief of coronary symptoms should be used cautiously (concern about reduced blood flow in severe stenosis)
  • Prevention of infective endocarditis: antibiotic prophylaxis is recommended during dental or surgical procedures in patients with prosthetic valves and others (according to guidelines)
• Recovery period and self-management
  • Blood pressure management, a low-sodium diet and weight management, regular light exercise (according to symptoms), and smoking cessation
  • Patients with mechanical valves need to take warfarin and undergo regular INR testing (as directed by the prescribing physician)
  • Before invasive procedures such as dental treatment or acupuncture after surgery, antibiotic prophylaxis and precautions against bleeding and infection are necessary
• Risk of complications: heart failure, infective endocarditis, cardiac arrest and sudden death, atrial fibrillation and thromboembolism (in the case of mechanical valves)

Checklist Before an Outpatient Visit (Including Example Questions)

• Items and information to prepare
  • A list of all medications currently being taken (including prescription drugs, OTC medications, and herbal medicines) and the times they are taken
  • Results of previous tests such as transthoracic/transesophageal echocardiography (TTE/TEE), cardiac CT, and cardiac catheterization (image files if possible)
  • Symptom diary: whether dyspnea, chest pain, or syncope occurs during exercise; the activity level when it occurs (e.g., while walking or climbing stairs); onset and progression
  • Medical history: history of rheumatic fever, congenital heart disease, previous endocarditis, surgical history, and pregnancy history (women)
  • Allergies (especially to medications and contrast media)
  • Smoking, alcohol consumption, occupational activity, and changes in exercise capacity
• What to submit or show to the doctor at the outpatient visit
  • Test records (echocardiography reports), recent blood pressure and weight measurements, and the most recent INR value (for patients taking anticoagulants)
• Examples of questions to write down in advance for the outpatient visit
  • A specific symptom checklist, such as “Have you experienced shortness of breath or fainting during exercise in the past 3 months?”
  • “What severity category does my current echocardiogram fall into (what are the valve area, mean gradient, and peak velocity values)?” (diagnosis-related question)

General Examples of Questions to Ask the Doctor

• How was the severity of my valve stenosis assessed (including the valve area, mean gradient, and peak velocity values)?
• Given my current condition, which treatment is more appropriate, surgery (AVR) or TAVI? What is the reason?
• What will my prognosis be if I do not undergo surgery? If symptoms appear, how urgently will surgery be needed?
• If I undergo valve replacement, which would you recommend: a mechanical valve or a tissue valve? Please explain the advantages and disadvantages of each (such as anticoagulation and the risk of reoperation).
• What restrictions will there be on daily activities and exercise before and after surgery, and what will the long-term follow-up plan (testing schedule) be?

Examples of Disease-Specific Questions

• Based on my test results, can you show me the specific values indicating whether I have severe aortic valve stenosis (whether they meet criteria such as valve area <1.0 cm², mean gradient ≥40 mmHg, and peak velocity ≥4.0 m/s)? Do I meet the criteria for a recommendation for surgery or TAVI?
• (For women who are planning a pregnancy) I am planning a pregnancy. What are the risks associated with pregnancy and delivery with aortic valve stenosis, and what management is recommended (timing before and after surgery, and adjustment of anticoagulants)?

(If necessary, printing the questions above or saving them on a smartphone for consultation with the doctor can help facilitate the medical visit.)