Severe aortic stenosis — structured written assessment

SAQ 1 (10 marks)

Practice scenario. A 79-year-old woman has exertional breathlessness. Echo: aortic valve area 0.8 cm², mean gradient 32 mm Hg, peak velocity 3.6 m/s, LVEF 58%, stroke volume index 31 mL/m², small thick-walled left ventricle. Blood pressure during the study was 168/92 mm Hg. Tricuspid valve; femoral arteries look adequate on screening. ^{[1] [2]}

1. Classify the valve using the 2025 ESC/EACTS categories and give the criteria. (3) ^[1]
2. Why must the blood pressure be addressed before the next study? (2) ^[2]
3. Which test confirms severity, and what thresholds apply to her? (3) ^{[1] [2]}
4. Once blood pressure is controlled, the measurements are confirmed and no other cause of low stroke volume is found; severity is confirmed. Outline the intervention decision under ESC/EACTS 2025. (2) ^{[1] [2]}

Model answers

1. On these numbers, low-flow, low-gradient AS with preserved LVEF: mean gradient below 40 mm Hg, AVA ≤1 cm², SVi ≤35 mL/m², LVEF ≥50% (1 mark for the label, 2 for the criteria). This pattern is frequent in women, whose ventricles are more often concentric with a smaller cavity and stroke volume, and it may contribute to underdiagnosis. ^[1]
2. ACC/AHA 2020 explains that hypertension imposes a second pressure load on the left ventricle and lowers forward stroke volume and the transaortic gradient (1). If a study recorded during hypertension suggests only moderate AS, ACC/AHA advises repeating it once blood pressure is better controlled so that severe AS is not missed (1). ^[2]
3. CT aortic valve calcium scoring (1). ESC/EACTS 2025: above 1200 AU in women indicates severe AS (sensitivity and specificity about 85%), and severe AS is unlikely below 800 AU (1). ESC/EACTS 2025 requires cautious interpretation in patients who can have severe AS without pronounced calcification, such as bicuspid valves, concomitant amyloidosis or predominantly fibrotic stenosis associated with post-rheumatic, radiation-induced or inflammatory disease. ACC/AHA 2020 uses 1300 AU in women (1). ESC/EACTS 2025 adds that CT calcium scoring should be performed in women with discordant echocardiographic parameters. ^{[1] [2]}
4. ESC/EACTS 2025: intervention should be considered in symptomatic low-flow (SVi ≤35 mL/m²), low-gradient (below 40 mm Hg) AS with normal LVEF (≥50%) after careful confirmation that AS is severe (class IIa, level B) (1). Other explanations, such as measurement error, uncontrolled blood pressure and conditions lowering stroke volume, must be carefully excluded first. At 70 years or older with tricuspid AS, TAVI is recommended if the anatomy is suitable (transfemoral access, annulus dimensions, device landing-zone calcification pattern and coronary obstruction risk) (class I, level A), with the mode decided by Heart Team assessment (class I, level C) (1). ^[1]

SAQ 2 (10 marks)

Practice scenario. A 67-year-old man is referred after a murmur was heard at a routine check. He denies symptoms. Echo: peak velocity 4.6 m/s, mean gradient 55 mm Hg, aortic valve area 0.7 cm², LVEF 62%. He completes a treadmill test without symptoms or a fall in blood pressure. STS-predicted mortality is 1.2% and EuroSCORE II 1.0%; the Heart Team judges his procedural risk low. ^{[1] [2]}

1. Name two findings that would make intervention recommended now under ESC/EACTS 2025. (2) ^[1]
2. State the 2025 ESC/EACTS position on early intervention in his situation and the features that strengthen it. (3) ^[1]
3. Summarise the randomised evidence for early intervention. (3) ^{[31] [30] [54] [55]}
4. He opts for intervention. How do ESC/EACTS 2025 and ACC/AHA 2020 guide the choice of procedure? (2) ^{[1] [2]}

Model answers

1. Symptoms or reduced exercise capacity attributable to AS uncovered by exercise testing; such patients are treated as symptomatic, and ESC/EACTS 2025 recommends intervention in symptomatic severe high-gradient AS (class I, level B) (1). An LVEF below 50% without another cause, for which ESC/EACTS 2025 recommends intervention (class I, level B) (1). ^[1]
2. ESC/EACTS 2025: in asymptomatic patients (confirmed by a normal exercise test, if feasible) with severe high-gradient AS and LVEF ≥50%, intervention should be considered as an alternative to close active surveillance if the procedural risk is low (class IIa, level A) (1). In asymptomatic severe AS with LVEF ≥50% and low procedural risk, it should also be considered if one feature is present (class IIa, level B). The features are very severe AS (mean gradient ≥60 mm Hg or Vmax above 5.0 m/s), or severe calcification (ideally on CT) with Vmax progression ≥0.3 m/s per year. They also include BNP or NT-proBNP more than three times the age- and sex-corrected normal range, confirmed on repeat without other explanation, or LVEF below 55% without another cause (1). Intervention should also be considered in asymptomatic severe AS with a sustained fall in blood pressure above 20 mm Hg during exercise testing (class IIa, level C); in the text, restricted resources or long waiting lists favour early intervention (1). ^[1]
3. EARLY TAVR (asymptomatic severe AS): primary composite of death, stroke or unplanned cardiovascular admission 26.8% with early transfemoral TAVI vs 45.3% with clinical surveillance (HR 0.50); during a median follow-up of 3.8 years, 87.0% of the surveillance group underwent valve replacement (1). ESC/EACTS 2025 notes that the result was driven by the 26.2% of the surveillance group who converted to TAVI within 6 months of randomisation because of symptoms or adverse prognostic factors, with no significant difference in stroke or all-cause mortality over 5-year follow-up. ESC/EACTS 2025 notes that the two surgical trials below were small, enrolled selected younger patients at low surgical risk (mean ages 64 and 67 years) and mostly very severe AS. RECOVERY (asymptomatic very severe AS, defined as AVA ≤0.75 cm² with Vmax ≥4.5 m/s or mean gradient ≥50 mm Hg): the primary end point of operative mortality or cardiovascular death was 1% with early surgery vs 15% with conservative care (HR 0.09). AVATAR (severe asymptomatic AS, LVEF ≥50%, negative exercise test), extended follow-up at median 63 months: the primary composite of death, myocardial infarction, stroke or unplanned heart failure admission was 23.1% with early surgery vs 46.8% with conservative treatment (1). EVOLVED (asymptomatic severe AS with myocardial fibrosis on CMR) did not reduce its primary end point of all-cause death or unplanned AS-related hospitalisation (18% with early intervention vs 23% with conservative management; HR 0.79). It was underpowered, median time to intervention in the early-intervention arm was 5 months, and the trial reported a wide 95% CI around the primary end point. A meta-analysis of the four trials showed significantly fewer unplanned cardiovascular or heart failure admissions and strokes, but no significant reduction in all-cause or cardiovascular mortality (1). ESC/EACTS 2025 notes that the pooled trials were heterogeneous and the analysis was study-level. ^{[31] [30] [54] [55] [1]}
4. ESC/EACTS 2025: SAVR is recommended below 70 years if surgical risk is low, meaning STS-PROM and EuroSCORE II below 4% with Heart Team assessment (class I, level B); his scores are both below 4% and the Heart Team agrees (1). ACC/AHA 2020: the stem gives none of its listed asymptomatic triggers (abnormal exercise blood pressure response, elevated BNP, rapid progression or velocity ≥5 m/s). Its recommendation for SAVR in preference to TAVI covers asymptomatic patients considered for AVR because of these triggers (1). ACC/AHA also notes that TAVI-versus-SAVR RCTs included only symptomatic patients, and that asymptomatic patients with COR 2a indications should undergo SAVR or wait for a COR 1 indication. ^{[1] [2]}