What is the management approach for patients with aortic stenosis?

Management of Aortic Stenosis

Symptomatic Severe Aortic Stenosis: Immediate Intervention Required

All patients with symptomatic severe aortic stenosis require aortic valve replacement (AVR), as survival without intervention averages only 2-3 years after symptom onset. 1 The decision between transcatheter aortic valve replacement (TAVR) and surgical AVR (SAVR) depends on surgical risk stratification, not patient preference alone. 2

Defining Severe Aortic Stenosis

Severe AS is confirmed when echocardiography demonstrates: 1

• Aortic valve area <1.0 cm²
• Mean pressure gradient >40 mmHg
• Peak velocity >4 m/s

Risk-Based Treatment Algorithm

Low surgical risk (STS-PROM <4%): SAVR is preferred, particularly in younger patients with longer life expectancy. 1 These patients benefit from the proven long-term durability of surgical valves. 3

Intermediate risk (STS-PROM 4-8%): Either SAVR or TAVR is appropriate based on anatomical factors, frailty assessment, and patient age. 1 The Heart Valve Team should evaluate chest anatomy, prior cardiac surgery, and comorbidities. 2

High risk (STS-PROM >8%): TAVR is generally preferred over SAVR. 1 The European Society of Cardiology specifically recommends TAVR for patients with porcelain aorta, hostile chest anatomy, multiple comorbidities, frailty, disability, or oxygen-dependent lung disease. 4

Critical Illness and Cardiogenic Shock

In critically ill patients with cardiogenic shock, balloon aortic valvuloplasty (BAV) serves as a bridge to definitive treatment. 4 The European Society of Cardiology recommends BAV for hemodynamic stabilization before proceeding to either TAVR or SAVR. 4 After stabilization, patients require urgent evaluation by the Heart Valve Team for definitive intervention. 4

Asymptomatic Severe Aortic Stenosis: Selective Early Intervention

Most asymptomatic patients with severe AS should undergo watchful waiting, but specific high-risk features warrant early prophylactic AVR (Class IIa indication). 2, 1

Indications for Early Intervention in Asymptomatic Patients

Very severe AS with low surgical risk: Intervention is reasonable when peak velocity exceeds 5.0 m/s (ACC/AHA) or 5.5 m/s (ESC) in patients with low surgical risk. 2

Abnormal exercise testing: AVR is indicated if exercise testing reveals: 2, 1

• Exercise-limiting symptoms
• Blood pressure drop during exercise
• Decreased exercise tolerance

Evidence of LV decompensation: Consider early intervention when multimodality imaging demonstrates: 2

• LVEF <50% without other explanation
• Reduced global longitudinal strain
• Extensive myocardial fibrosis on cardiac MRI
• Disproportionate LV hypertrophy without hypertension

Rapid disease progression: Early AVR may be considered when peak velocity increases ≥0.3 m/s per year. 2

Concurrent cardiac surgery: AVR is indicated (Class I) when asymptomatic patients with severe AS require other cardiac surgery. 2

The RECOVERY trial demonstrated lower operative mortality and cardiovascular death at 6 years with early AVR in very severe AS (AVA ≤0.75 cm², peak velocity ≥4.5 m/s, or mean gradient ≥50 mmHg), suggesting potential expansion of early intervention indications. 2

Special Diagnostic Challenges

Low-Flow, Low-Gradient AS with Reduced EF (Classical LF-LG)

Dobutamine stress echocardiography is essential to confirm true severe stenosis and assess flow reserve. 2, 1 Intervention is appropriate (Class IIa/IIb) if: 2

• True severe AS is confirmed (AVA remains <1.0 cm² with increased flow)
• Flow reserve is present (stroke volume increases with dobutamine)

Paradoxical Low-Flow, Low-Gradient AS with Preserved EF

This entity occurs when AVA <1.0 cm², mean gradient <40 mmHg, LVEF is preserved, but stroke volume index <35 mL/m². 2 Cardiac CT for aortic valve calcium scoring helps confirm true severe AS—up to 50% of these patients have severe disease despite low gradients. 2 These patients should be classified as stage D3 (symptomatic) or C3 (asymptomatic) and managed accordingly. 2

Normal-Flow, Low-Gradient AS

When AVA <1.0 cm² but mean gradient <40 mmHg with normal flow, multimodality imaging including CT calcium scoring is critical. 2 Some patients have moderate-to-severe rather than severe AS, while others have true severe disease with discordant measurements. 2

Surveillance Strategy

Mild AS: Annual history and physical examination; echocardiography every 3-5 years. 2

Moderate AS: Annual assessment with echocardiography every 1-2 years, more frequently if significant valve calcification is present. 2

Severe asymptomatic AS: Echocardiography every 6-12 months with careful symptom assessment. 5 Patients must be educated to report symptoms immediately, as mortality increases dramatically once symptoms develop. 5

Concurrent Conditions Requiring Evaluation

Coronary Artery Disease

Coronary angiography is indicated in all patients being considered for AVR, as CAD prevalence ranges from 40-75%. 2 The Heart Valve Team should decide on a case-by-case basis whether to revascularize before TAVR, particularly for multivessel or left main disease. 2 For patients requiring SAVR, combined AVR plus CABG is appropriate when significant CAD is present. 1

Mitral Valve Disease

Moderate-to-severe mitral regurgitation occurs in approximately 20% of AS patients. 2 Secondary MR often improves after AVR, but primary MR, atrial fibrillation, pulmonary hypertension, and reduced EF predict poor outcomes. 2 Surgical AVR is generally preferred when significant other valve disease coexists, unless surgical risk is prohibitive. 1

Cardiac Amyloidosis

ATTR cardiac amyloidosis coexists with AS in 6-25% of elderly patients and signifies higher all-cause mortality. 2 Maximum LV wall thickness is a major prognostic determinant regardless of intervention type. 2 While systematic screening is not currently recommended, consider amyloidosis when LV wall thickness appears disproportionate to AS severity. 2

Critical Pitfalls to Avoid

Do not delay intervention in symptomatic patients. Once symptoms develop, average survival is only 2% per month without treatment. 6 The question is not "if" but "when" to replace the valve. 2

Do not rely solely on gradients in low-flow states. Calculate valve area, as gradients may underestimate severity when cardiac output is reduced. 4, 7 Both stroke volume index and EF should guide patient selection. 2

Recognize that symptoms may be masked in elderly patients due to reduced mobility, comorbidities, or self-limitation of activity. 2, 1 Exercise testing can unmask occult symptoms in apparently asymptomatic patients. 1

Avoid aggressive vasodilation in acute decompensation. While nitrates may be reasonable for hypertensive heart failure, hypotension must be avoided. 7 Maintain adequate preload, as these patients are preload-dependent. 4, 1, 7

Consider medical futility appropriately. Intervention is not recommended when life expectancy is <1 year from non-cardiac causes or in patients with moderate-to-severe dementia. 4, 1 Palliative BAV may be considered in select cases with limited life expectancy. 1

Pre-Intervention Evaluation

The Heart Valve Team must review: 2

• Echocardiographic confirmation of AS severity
• Symptom status (exercise testing if unclear)
• Surgical risk assessment (EuroSCORE II, STS-PROM)
• Coronary anatomy via angiography
• Baseline clinical data including pulmonary function tests
• Dental evaluation and treatment of acute issues
• Social support for recovery
• Frailty assessment
• Life expectancy and patient values/preferences

Transfemoral access is the preferred approach for TAVR, with alternative access (transaortic, trans-subclavian/axillary, transapical, or trans-carotid) reserved for unsuitable femoral anatomy. 2