Resolution of apparent discrepancies in measures of AS severity

AS velocity >4 m/s and AVA >1.0 cm2
 1. Check LVOT diameter measurement and compare with previous studies
 2. Check LVOT velocity signal for flow acceleration
 3. Calculate indexed AVA when
  a. Height is <135 cm (5′5″)
  b. BSA <1.5 m2
  c. BMI <22 (equivalent to 55 kg or 120 lb at this height).
 4. Evaluate AR severity
 5. Evaluate for high cardiac output
  a. LVOT stroke volume
  b. 2D LV EF and stroke volume
Likely causes: high output state, moderate–severe AR, large body size

AS velocity ≤4 m/s and AVA ≤1.0 cm2
 1. Check LVOT diameter measurement and compare with previous studies
 2. Check LVOT velocity signal for distance from valve
 3. Calculate indexed AVA when
  a. Height is <135 cm (5′5″)
  b. BSA <1.5 m2
  c. BMI <22 (equivalent to 55 kg or 120 lb at this height).
 4. Evaluate for low transaortic flow volume
  a. LVOT stroke volume
  b. 2D LV EF and stroke volume
  c. MR severity
  d. Mitral stenosis
 5. When EF <55%
  a. Assess degree of valve calcification
  b. Consider dobutamine stress echocardiography
Likely causes: low cardiac output, small body size, severe MR