What is the recommended management approach for patients with severe aortic stenosis?

Management of Severe Aortic Stenosis

All symptomatic patients with severe aortic stenosis require valve replacement, with the choice between transcatheter aortic valve replacement (TAVR) and surgical aortic valve replacement (SAVR) determined primarily by surgical risk assessment. 1, 2

Initial Assessment and Risk Stratification

Confirm severe aortic stenosis using echocardiographic criteria: aortic valve area ≤1.0 cm², peak velocity ≥4 m/sec, or mean gradient ≥40 mmHg. 1, 2

Determine symptom status by taking a thorough history focused on:

• Exertional dyspnea, angina, syncope, or dizziness 1
• Exercise capacity limitations below age and sex-specific predicted metabolic equivalents 1
• If uncertainty exists about symptoms in elderly or sedentary patients, perform exercise stress testing to identify exercise-induced symptoms, limited exercise capacity, or abnormal blood pressure response 1

Calculate surgical risk using the STS-PROM score and Heart Team assessment: 1

• Low risk: STS-PROM <3% with no additional risk factors
• Intermediate risk: STS-PROM 4-8%
• High risk: STS-PROM >8%
• Prohibitive risk: ≥50% estimated 30-day mortality or irreversible morbidity, or factors such as frailty, prior radiation therapy, porcelain aorta, severe hepatic or pulmonary disease 1

Management Algorithm for Symptomatic Patients

For symptomatic severe AS, proceed with valve replacement as follows: 1, 2

Low surgical risk (STS <3%):

• SAVR is the preferred approach 1
• TAVR is emerging as a reasonable alternative in selected patients >74 years old 3, 4

Intermediate surgical risk (STS 4-8%):

• Either TAVR or SAVR is appropriate 1, 5
• The Heart Team should consider patient anatomy, frailty, and patient preference 1

High surgical risk (STS >8%):

• TAVR is a reasonable alternative to SAVR 1, 5

Prohibitive surgical risk:

• TAVR is the recommended approach 1
• If TAVR is not feasible, balloon aortic valvuloplasty may be considered for palliation as a bridge to decision-making 1

Medical therapy alone is rarely appropriate for symptomatic patients and should not be used as definitive management. 1, 2

Management Algorithm for Asymptomatic Patients

Most asymptomatic patients with normal left ventricular function should undergo watchful waiting with regular clinical and echocardiographic follow-up every 6-12 months. 2

Proceed with valve replacement in asymptomatic patients if ANY of the following are present: 1, 2, 6

• Left ventricular ejection fraction <50% 6
• Very severe AS with peak velocity ≥5 m/sec or mean gradient ≥60 mmHg 1, 6
• Abnormal exercise stress test showing exercise-induced symptoms, limited exercise capacity, or hypotensive response 1, 6
• Rapid progression of stenosis (increase in peak velocity ≥0.3 m/sec per year) 2
• Undergoing cardiac surgery for another indication 6

Important caveat: The natural history of asymptomatic severe AS is not benign, with 1-year, 2-year, and 5-year survival rates of only 67%, 56%, and 38% respectively in unoperated patients. 7 However, current guidelines still recommend watchful waiting for most asymptomatic patients without the above high-risk features. 1, 2

Special Populations

Low-flow, low-gradient AS (stroke volume index <35 ml/m², mean gradient <40 mmHg):

• Perform dobutamine stress echocardiography to distinguish true-severe from pseudo-severe AS 1, 2
• If flow reserve is present on dobutamine and truly severe AS is confirmed, proceed with AVR 6
• If pseudo-severe AS is identified, medical management is appropriate 6

Patients requiring non-cardiac surgery:

• Asymptomatic patients can undergo elective non-cardiac surgery safely, though with increased risk of heart failure 6
• Consider AVR before non-cardiac surgery if the procedure involves large volume shifts 6
• Symptomatic patients should have AVR considered before elective non-cardiac surgery 6

Medical Management Principles

While awaiting valve replacement or in patients not candidates for intervention: 1

• Maintain adequate preload and avoid excessive diuresis 2
• Control heart rate to maintain adequate diastolic filling time and avoid tachycardia 2
• Avoid vasodilators and positive inotropes due to risk of hemodynamic destabilization 1
• Control blood pressure and other cardiovascular risk factors 1
• Do not use statins to prevent progression of AS, as they are not effective for this indication 1

Observational data suggest beta blockers and statins may improve survival in unoperated patients (hazard ratios 0.52 for each), though this requires further validation. 7

Heart Team Approach

All complex decisions should involve a multidisciplinary Heart Team comprising cardiac surgery, interventional cardiology, cardiac imaging, anesthesiology, and geriatrics expertise. 1 This is particularly critical for:

• Asymptomatic patients being considered for intervention 1
• Complex transcatheter or surgical procedures 1
• Patients with challenging anatomy (bicuspid valves, hostile calcium, small annuli) 3

TAVR Outcomes and Complications

TAVR demonstrates sustained mortality benefit at 2 years compared to medical therapy in inoperable patients (43.3% vs 68.0% mortality, p<0.001), with improved functional status and reduced rehospitalization. 8

Key TAVR-specific complications to monitor: 1, 5

• Stroke: 6-7% (higher than SAVR at 2%) 1
• Paravalvular aortic regurgitation 1, 5
• Permanent pacemaker requirement: 2-43% depending on valve type 1
• Vascular access complications: 17% 1
• Acute kidney injury 1

The mortality benefit of TAVR may be attenuated in patients with extensive comorbidities, so careful patient selection remains critical. 8