When should a patient with severe aortic (AV) stenosis undergo surgical intervention?

When to Operate on Aortic Stenosis

Patients with severe aortic stenosis and any symptoms (syncope, dyspnea, angina) require urgent aortic valve replacement, as this represents a Class I indication and delays in surgery lead to rapid clinical deterioration with mortality rates approaching 50% at 2 years without intervention. 1, 2

Immediate Surgical Indications (Class I)

Symptomatic Severe AS

• Any valve-related symptoms mandate urgent AVR, including:
  • Syncope or presyncope 1, 2
  • Exertional dyspnea or heart failure 1
  • Angina pectoris 1
• Once symptoms appear, prognosis deteriorates rapidly with sudden cardiac death risk increasing from 3-5% (asymptomatic) to 8-34% (symptomatic) 2, 3
• Symptomatic patients have approximately 50% mortality at 2 years without intervention 3

Asymptomatic Severe AS with High-Risk Features

• LV systolic dysfunction (LVEF <50%) without other explanation 1, 4
• Symptoms develop during exercise testing 1, 2
• Concomitant cardiac surgery (CABG, ascending aorta surgery, or other valve surgery) 1

Strong Consideration for Surgery (Class IIa)

Asymptomatic Patients with Adverse Prognostic Features

• Fall in blood pressure below baseline during exercise testing 1
• Rapid progression: peak velocity increase ≥0.3 m/s per year with moderate-to-severe calcification 1
• Very severe AS: peak velocity >5 m/s 1
• Ascending aorta dilation >50 mm (or >27.5 mm/m² BSA) 1

Low-Flow Low-Gradient AS

• Symptomatic LFLG AS with reduced LVEF and contractile reserve 1
• Symptomatic LFLG AS with preserved LVEF after careful confirmation of severity 1

May Consider Surgery (Class IIb)

• Excessive LV hypertrophy (≥15 mm) not explained by hypertension in asymptomatic severe AS 1
• LFLG AS with reduced LVEF without contractile reserve 1
• Moderate AS undergoing other cardiac surgery 1

Defining Severe AS

Severe aortic stenosis requires meeting these echocardiographic criteria 1, 2:

• Aortic valve area <1.0 cm² (or indexed <0.6 cm²/m² BSA)
• Peak velocity ≥4.0 m/s
• Mean gradient ≥50 mmHg (at normal transvalvular flow)

Critical Pitfalls to Avoid

• Never delay surgery for medical optimization in symptomatic patients - medical therapy is reserved only for non-operable patients 2
• Do not assume nursing home status excludes intervention - many nursing home patients are appropriate TAVR candidates 4
• Before attributing syncope to AS, exclude other causes, particularly in patients with syncope at rest 2
• Use vasodilators (ACE inhibitors, ARBs) with extreme caution in severe AS due to risk of substantial hypotension 2
• Asymptomatic patients with good exercise tolerance have good prognosis even with severe AS, but require close monitoring 1

Choosing Between SAVR and TAVR

• TAVR is preferred for high surgical risk (STS-PROM ≥8%) or prohibitive surgical risk (≥50% mortality at 30 days) 2, 4
• SAVR remains appropriate for low-risk patients, particularly younger patients requiring lifetime management considerations 5
• Multidisciplinary heart team evaluation is essential for individualized treatment selection 5

Surveillance for Asymptomatic Patients

When surgery is deferred in asymptomatic patients with preserved LVEF and normal stress testing 4:

• Serial echocardiography monitoring LV function 4
• Patient education to report new symptoms immediately 4
• Monitor for syncope, dyspnea, chest pain, or decreased exercise tolerance 4
• Intervention threshold: LVEF decline to <50% or symptom development 4