What is the recommended treatment strategy for severe aortic stenosis, including indications for surgical aortic valve replacement versus transcatheter aortic valve implantation and medical management?

Treatment of Aortic Stenosis

All patients with symptomatic severe aortic stenosis require aortic valve replacement (either surgical or transcatheter) because medical therapy alone results in approximately 50% mortality within 2-3 years. 1

Defining Severe Aortic Stenosis

Severe aortic stenosis is characterized by:

• Aortic valve area ≤1.0 cm² 2
• Peak velocity ≥4 m/s 2
• Mean gradient ≥40 mmHg 2

Treatment Algorithm for Symptomatic Severe AS

Immediate Intervention Required

Valve replacement is mandatory for all symptomatic patients presenting with the three hallmark symptoms: 1

• Angina
• Syncope or near-syncope
• Heart failure-related dyspnea

Choosing Between TAVR and Surgical AVR

The decision is based on surgical risk stratification:

Prohibitive Surgical Risk (≥50% predicted 30-day mortality)

TAVR is the recommended treatment for patients with: 3, 1

• Frailty
• Porcelain aorta
• Prior chest radiation
• Severe hepatic or pulmonary disease
• Other factors predicting irreversible morbidity

High Surgical Risk (STS score ≥8%)

TAVR is a reasonable alternative to surgical AVR in this population. 3, 1 The choice should involve Heart Team discussion, but TAVR is generally preferred. 3

Intermediate or Low Surgical Risk (STS score <8%)

Either TAVR or surgical AVR is acceptable, with the decision made by a multidisciplinary Heart Team. 1 However, important considerations include:

• For patients <65 years old: Surgical AVR is generally preferred due to proven long-term durability and lower reintervention rates. 4, 5
• For patients 65-80 years old: Choice depends on expected longevity (greater in women), anatomical factors, and patient preferences. 6
• For patients >80 years old: TAVR is preferred based on lower mortality and morbidity compared to surgical AVR. 6

Treatment of Asymptomatic Severe AS

Class I Indications (Must Intervene)

Proceed with AVR immediately if any of the following are present: 3, 1

• Left ventricular ejection fraction <50% (not due to another cause) 3, 1
• Patient undergoing other cardiac surgery (CABG, aortic surgery, or other valve surgery) 3, 1
• Abnormal exercise test showing symptoms on exercise clearly related to AS 3
• Abnormal exercise test showing fall in blood pressure below baseline 3

Class IIa Indications (Should Strongly Consider)

AVR should be considered in asymptomatic patients with: 3, 1

• Very severe AS (peak velocity ≥5.5 m/s or mean gradient ≥60 mmHg) 3, 1
• Rapid progression (increase in jet velocity ≥0.3 m/s per year with severe valve calcification) 3, 1
• Markedly elevated BNP (>3× age- and sex-adjusted normal) 1
• Moderate AS undergoing CABG or other cardiac surgery 3

Class IIb Indications (May Consider)

AVR may be considered in low-risk asymptomatic patients with: 3, 1

• Excessive LV hypertrophy without history of hypertension 3
• Mean gradient increase with exercise >20 mmHg 3
• High-demand occupations or lifestyles (commercial pilots, elite athletes) 1

Special Clinical Scenarios

Low-Flow, Low-Gradient AS with Reduced EF

For patients with low gradient (<40 mmHg) and reduced EF: 3

• Perform dobutamine stress echocardiography to assess flow reserve 2
• If flow reserve is present: AVR should be performed (carries acceptable risk and improves outcomes) 3
• If flow reserve is absent: AVR may still be considered despite higher operative mortality, as it can improve EF and clinical status 3

Low-Flow, Low-Gradient AS with Normal EF (Paradoxical)

Surgery should only be performed when: 3

• Symptoms are clearly present
• Comprehensive evaluation confirms significant valve obstruction 3

Concomitant Coronary Artery Disease

For patients with severe AS and CAD: 2

• Surgical AVR plus CABG is appropriate for most patients 2
• Revascularization with PCI or CABG in addition to TAVR does not increase risk of death or disabling stroke at 2 years 2

Medical Management: What NOT to Do

Medical therapy has no role in treating symptomatic severe AS and the following should be avoided: 3, 1

• Statins are NOT indicated for preventing AS progression (Class III) 3, 1
• Aggressive diuretics should be avoided in patients awaiting surgery due to risk of hemodynamic collapse 3, 1
• Vasodilators should be avoided before AVR due to risk of destabilization 3, 1
• Positive inotropes should be avoided in patients awaiting surgery 3

Limited Role for Medical Therapy

For asymptomatic patients or perioperative management: 2

• Maintain adequate preload without excessive diuresis 2
• Control heart rate to maintain adequate diastolic filling time and avoid tachycardia 2
• Target systolic blood pressure 100-120 mmHg in acute settings 2
• Beta-blockers are preferred for blood pressure control 2

Balloon Aortic Valvuloplasty

Balloon valvuloplasty has extremely limited indications (Class IIb): 3, 1

• Palliation in patients unsuitable for AVR due to serious comorbidities 3
• Bridge to surgical AVR 3
• Select patients with limited life expectancy 2

Surveillance for Asymptomatic Patients

Asymptomatic individuals require: 1

• Regular clinical assessment and echocardiographic follow-up 1
• Re-evaluation every 6 months if risk factors are present 3
• Exercise testing to unmask latent symptoms in apparently asymptomatic patients 1, 2
• Prompt re-evaluation if aortic jet velocity increases ≥0.3 m/s per year 1

Critical Pitfalls to Avoid

Delaying AVR after symptom onset markedly reduces survival—prompt intervention is essential. 1 The following errors are common:

• Missing reduced LVEF (<50%) in an asymptomatic patient constitutes a missed Class I indication for AVR 1
• Prescribing statins with expectation of slowing AS progression is ineffective (Class III) 1
• Using vasodilators or aggressive diuresis in severe AS patients awaiting surgery can cause hemodynamic instability 1
• Assuming elderly patients are asymptomatic without exercise testing—symptoms may be masked by comorbidities or reduced mobility 2
• Proceeding with intervention in patients with life expectancy <1 year or severe dementia without considering medical futility 2

Heart Team Approach

TAVR should only be performed in hospitals with cardiac surgery on-site, and all decisions should involve a multidisciplinary Heart Team including: 3, 2

• Cardiologists with valvular expertise
• Structural interventional cardiologists
• Imaging specialists
• Cardiovascular surgeons
• Cardiovascular anesthesiologists

The Heart Team must assess: 2

• Individual patient risks
• Technical suitability and anatomical factors
• Patient goals and life expectancy
• Benefits and risks of each approach