What is the most appropriate next step for an asymptomatic patient with severe aortic stenosis (AS) and normal left ventricular function (EF)?

Management of Asymptomatic Severe Aortic Stenosis

For an asymptomatic patient with severe aortic stenosis (AS) and normal ejection fraction (EF), the most appropriate next step is a treadmill test to assess for exercise-induced symptoms before making a definitive management decision.

Assessment of Asymptomatic Severe AS

Initial Evaluation

• The patient has severe AS with a gradient >40 mmHg and normal EF
• The first patient is active (jogs 3 km daily) with no symptoms and has a late-peaking carotid pulse
• The second patient is sedentary and asymptomatic with severe AS and normal EF

Guideline-Based Approach

The ESC/EACTS and ACC/AHA guidelines provide clear recommendations for asymptomatic severe AS:

1. Exercise Testing:

   • Both guidelines strongly recommend exercise testing for asymptomatic patients with severe AS to unmask symptoms 1
   • Class I recommendation: "Asymptomatic patients with severe AS should undergo surgery when they develop symptoms during exercise testing" 1
   • Exercise-induced symptoms, abnormal blood pressure response, or decreased exercise tolerance are indications for intervention

2. Risk Stratification: After exercise testing, further risk assessment should include:

   • Very severe AS (Vmax ≥5 m/s or mean gradient ≥60 mmHg)
   • Rapid progression (increase in velocity ≥0.3 m/s/year)
   • Excessive calcification
   • Abnormal LV function (even with preserved EF)
   • Elevated BNP levels

Management Algorithm

Step 1: Exercise Testing

• Perform a treadmill test to assess for:
  • Exercise-induced symptoms (dyspnea, angina, syncope)
  • Blood pressure response (fall in BP below baseline)
  • Exercise capacity

Step 2: Decision Based on Exercise Test Results

• If symptoms or abnormal BP response occur during exercise:

  • Proceed to valve replacement (Class I recommendation) 1

• If no symptoms during exercise:

  • Assess for high-risk features:
    • Very severe AS (Vmax ≥5 m/s)
    • Rapid progression rate (≥0.3 m/s/year)
    • Excessive valve calcification
    • LV dysfunction (even with normal EF)
    • Elevated BNP levels
  • If multiple high-risk features are present, consider valve replacement
  • If no high-risk features, continue observation with close follow-up

Step 3: Follow-up Protocol

• For patients managed conservatively:
  • Clinical evaluation every 6 months
  • Echocardiography every 6-12 months for severe AS
  • Patient education about prompt reporting of symptoms

Special Considerations

Active vs. Sedentary Patient

• For the active patient who jogs daily:
  • Exercise testing is particularly important to ensure true asymptomatic status during exertion
  • Late-peaking carotid pulse suggests severe obstruction

Sedentary Patient

• For the sedentary 72-year-old:
  • Exercise testing is crucial as symptoms may not be apparent due to limited activity
  • May have unrecognized exercise limitation that could be unmasked with testing

Pitfalls to Avoid

1. Misclassifying Symptomatic Patients: Patients may reduce activities to avoid symptoms or attribute symptoms to aging

   • Exercise testing helps identify truly asymptomatic patients

2. Delaying Intervention: Waiting too long for symptoms may result in:

   • Irreversible myocardial damage
   • Increased operative risk
   • Risk of sudden death (though rare at <1% per year)

3. Premature Intervention: Unnecessary valve replacement exposes patients to:

   • Procedural risks
   • Prosthetic valve complications
   • Need for anticoagulation (with mechanical valves)

Conclusion

Treadmill testing is the most appropriate next step for both patients with asymptomatic severe AS to guide further management decisions. This approach is supported by both European and American guidelines and allows for appropriate risk stratification before committing to valve replacement or continued observation.