Aortic stenosis

Differential Diagnosis

• Bicuspid aortic valve
• Rheumatic valve: fusion from outside-in of the valvular leaves
• Calcific degenerative stenosis

Pathophysiology

• LV outflow obstruction causing
  • Increased LV systolic pressure, hypertrophy, and dysfunction
  • Increased LVET
  • Increased LV diastolic pressure from hypertrophy
  • Decreased aortic pressure
• The above leads to decreased myocardial oxygenation resulting in myocardial ischemia and LV failure

Severity

• Mild: Vmax 2-2.9 m/s or mean gradient <20 mmHg
• Moderate: Vmax 3-3.9 m/s or mean gradient 20-39 mmHg
• Severe: Vmax ≥4 m/s or mean gradient ≥40 mmHg
  • AVA is usually ≤1 cm^2^
• Very severe: Vmax ≥5 m/s or mean gradient ≥60 mmHg

Examination

• Palpation
  • Sustained apical pulse
  • Palpable S4 (atrial kick)
  • Carotid pulse parvus and tardus
  • Apical-carotid delay
  • Brachial-radial delay
• Auscultation
  • Mid-late peaking, systolic, harsh ejection murmur
  • Soft and single S2 (can lose the A2)
  • S4, maybe
  • Ejection click with bicuspid valve

Investigations

• If severe and asymptomatic, do a stress test
• Symptomatic severe with low gradient and reduced LVEF, do a low-dose dobutamine stress echo
  • If Vmax or MG increases, then consider for surgery
• Symptomatic severe with low gradient and normal LVEF, do a cardiac CT (to quantify AV calcification) or TEE (to assess valve better)

Management

• Treat hypertension

Surgery

• Strong indications (Grade I)
  • Severe AS with symptoms by history or on exercise testing
  • Asymptomatic severe AS with LVEF <50%
  • Asymptomatic severe AS when undergoing other cardiac surgery
• Weak indications (Grade IIa)
  • Very severe AS and low surgical risk
  • Asymptomatic severe AS and decreased exercise tolerance or exercise-induced hypotension
  • Symptomatic low-flow/low-gradient AS with reduced LVEF with a low-dose dobutamine stress study that elicits severe AS
  • Symptomatic normotensive patients with low-flow/low-gradient severe AS with LVEF ≥50 percent (stage D3), if clinical, hemodynamic, and anatomic data support valve obstruction as the most likely cause of symptoms
• Very weak indications (Grade IIb)
  • Moderate AS undergoing another cardiac surgery
  • Asymptomatic severe AS with rapid progression and low surgical risk
• TAVR preferred for high-prohibitive risk for surgery
  • But not in bicuspid valve (because concomitant aortic root disease)

Prognosis

• Angina: 50% die in 5 years
• Syncope: 50% die in 3 years
• Heart Failure: 50% die in 2 years