Asymptomatic severe aortic stenosis unmasked on a treadmill — case discussion

Presentation

Practice case (not a real patient). A 71-year-old woman in a regional town is referred after her GP hears a systolic murmur. She says she has no symptoms and walks her dog daily, though more slowly than last year.^[1] Transthoracic echocardiography shows a severely calcified tricuspid aortic valve with severely reduced leaflet opening, a mean gradient of 51 mmHg, Vmax 4.5 m/s, aortic valve area 0.7 cm² and LVEF 60%.^[1][2]

Step 1 — How severe is it?

Under ESC/EACTS 2025, high-gradient AS is a mean gradient of 40 mmHg or more, Vmax of 4.0 m/s or more and AVA of 1 cm² or less (or 0.6 cm²/m² or less).^[1] It is considered severe irrespective of LV function and flow conditions.^[1] Under ACC/AHA 2020 Table 13, the Stage C1 (asymptomatic severe AS) row includes severe leaflet calcification/fibrosis or congenital stenosis with severely reduced leaflet opening.^[2] It also includes an aortic Vmax of 4 m/s or more or a mean ΔP of 40 mm Hg or more, normal LVEF and no symptoms; she fits that row.^[2] Her values are below the ESC/EACTS 2025 very severe threshold of a mean gradient of 60 mmHg or more or Vmax above 5.0 m/s.^[1] They are also below the ACC/AHA 2020 Table 13 very severe threshold of a Vmax of 5 m/s or more or a mean gradient of 60 mm Hg or more.^[2]

Step 2 — Is she really asymptomatic?

Her slower walks matter. ESC/EACTS 2025 says patients may gradually limit their activity over several years and deny actual symptoms that exercise testing can unmask.^[1] ACC/AHA 2020 finds exercise testing reasonable in asymptomatic severe AS (Stage C1) to assess physiological changes with exercise and to confirm the absence of symptoms (COR 2a, LOE B-NR).^[3] It says that, under the direct supervision of an experienced clinician with close monitoring of blood pressure and ECG, exercise testing in asymptomatic patients is relatively safe.^[3]

On a supervised treadmill test she becomes markedly breathless early in exercise and stops. ACC/AHA 2020 lists excessive dyspnoea early in exercise among the findings consistent with symptoms of AS.^[3] Patients with symptoms provoked by exercise testing should be considered symptomatic, even if the clinical history is equivocal.^[3]

Step 3 — What does that change?

ESC/EACTS 2025 says such patients should be treated as symptomatic.^[1] It recommends intervention in symptomatic patients with severe, high-gradient AS (mean gradient ≥40 mmHg, Vmax ≥4.0 m/s, AVA ≤1.0 cm² or ≤0.6 cm²/m² BSA) (Class I, Level B).^[1] ACC/AHA 2020 indicates AVR in adults with severe high-gradient AS (Stage D1) and symptoms of exertional dyspnea, HF, angina, syncope or presyncope by history or on exercise testing (COR 1, LOE A).^[3] She should not have further exercise testing: in symptomatic severe AS (Stage D1, aortic velocity ≥4.0 m/s or mean pressure gradient ≥40 mm Hg), ACC/AHA 2020 says it should not be performed because of the risk of severe hemodynamic compromise (COR 3: Harm, LOE B-NR).^[3]

Step 4 — TAVI or SAVR?

CT shows anatomy suitable for transfemoral TAVI (access, annulus dimensions, device landing-zone calcification pattern and coronary obstruction risk).^[1] ESC/EACTS 2025 recommends TAVI in patients 70 years or older with tricuspid AV stenosis, if the anatomy is suitable (Class I, Level A).^[1] It also recommends that the mode of intervention is based on Heart Team assessment of individual clinical, anatomical and procedural characteristics, incorporating lifetime management considerations and estimated life expectancy (Class I, Level C).^[1]

For patients for whom a bioprosthetic AVR is appropriate, ACC/AHA 2020 covers symptomatic patients with severe AS who are 65 to 80 years of age and have no anatomic contraindication to transfemoral TAVI.^[3] For them, either SAVR or transfemoral TAVI is recommended after shared decision-making about the balance between expected patient longevity and valve durability (COR 1, LOE A).^[3] ESC/EACTS 2025 recommends that aortic valve interventions are performed in Heart Valve Centres that report their local expertise and outcome data (Class I, Level C).^[1] In that row, the centres also have on-site interventional cardiology and cardiac surgical programmes and a structured collaborative Heart Team.^[1]

Step 5 — Had the test been normal

With a normal exercise test instead, ESC/EACTS 2025 says intervention should be considered in asymptomatic patients with severe, high-gradient AS and LVEF of 50% or more as an alternative to close active surveillance, if the procedural risk is low (Class IIa, Level A).^[1] If she had chosen surveillance, ESC/EACTS 2025 asks for follow-up at least every 6 months, and ACC/AHA 2020 Table 5 gives an echo every 6–12 months for severe asymptomatic AS (Stage C1, Vmax ≥4 m/s).^[1][2] The Table 5 aortic stenosis column is marked as applying with normal stroke volume.^[2] Its notes say the intervals apply to most patients with each valve lesion and do not take into consideration the etiology of the valve disease.^[2] They add that patients with mixed valve disease may require serial evaluations at intervals earlier than recommended for single-valve lesions.^[2]

Learning points

• An asymptomatic history is not enough in severe AS; exercise testing can unmask symptoms and haemodynamic intolerance (ESC/EACTS 2025 text).^[1]
• Symptoms provoked on exercise testing count as symptoms: ACC/AHA 2020 says the patient then meets a COR 1 recommendation for AVR (its row for adults with severe high-gradient AS, Stage D1, and symptoms of exertional dyspnea, HF, angina, syncope or presyncope by history or on exercise testing, COR 1, LOE A).^[3]
• Exercise testing should not be performed in symptomatic severe AS (Stage D1, aortic velocity ≥4.0 m/s or mean pressure gradient ≥40 mm Hg) because of the risk of severe hemodynamic compromise (ACC/AHA 2020, COR 3: Harm, LOE B-NR).^[3]
• State each guideline by body and year: ESC/EACTS 2025 recommends TAVI from 70 years with tricuspid AV stenosis and suitable anatomy (Class I, Level A); for patients for whom a bioprosthetic AVR is appropriate, ACC/AHA 2020 recommends SAVR or transfemoral TAVI after shared decision-making at 65 to 80 years in symptomatic patients with no anatomic contraindication to transfemoral TAVI (COR 1, LOE A).^[1][3]