What are the echocardiographic criteria for aortic valve repair?

Echocardiographic Criteria for Aortic Valve Repair

The primary echocardiographic criteria for aortic valve repair include valve morphology assessment, quantification of aortic stenosis severity (AVA ≤1.0 cm², mean gradient ≥40 mmHg, peak velocity ≥4 m/s), evaluation of aortic regurgitation, and assessment of left ventricular size and function.

Aortic Valve Morphology Assessment

• Valve structure and number of cusps:

  • Tricuspid vs. bicuspid vs. unicuspid valve morphology
  • Bicuspid valves require special consideration as they may be contraindicated for TAVI 1
  • Detailed assessment of cusp mobility, thickness, and calcification

• Calcification assessment:

  • Distribution and extent of valve calcification
  • Calcium scoring by MSCT can confirm severe aortic stenosis:
    • Men: ≥3000 AU (very likely severe AS), ≥2000 AU (likely severe AS)
    • Women: ≥1600 AU (very likely severe AS), ≥1200 AU (likely severe AS) 1

Quantification of Aortic Stenosis Severity

• Primary measurements:

  • Aortic valve area (AVA) ≤1.0 cm² or indexed AVA ≤0.6 cm²/m² 1
  • Mean pressure gradient ≥40 mmHg
  • Peak velocity ≥4 m/s

• Inconsistencies between parameters:

  • An AVA of 1.0 cm² typically corresponds to a mean gradient of only 21 mmHg and peak velocity of 3.3 m/s 2
  • When parameters are discordant, additional assessment is required

• Low-flow, low-gradient AS with preserved EF:

  • SVi <35 mL/m² despite normal EF
  • Mean gradient 30-40 mmHg
  • AVA ≤0.8 cm²
  • Requires confirmation by other techniques (3D TEE, MSCT, CMR) 1

• Low-flow, low-gradient AS with reduced EF:

  • Dobutamine stress echocardiography to distinguish true severe AS from pseudosevere AS
  • Assessment of flow reserve (increase in SV >20%) 1

Evaluation of Aortic Regurgitation

• Quantitative parameters:

  • Vena contracta width
  • Regurgitant volume and fraction
  • Effective regurgitant orifice area (EROA)

• Qualitative assessment:

  • Jet width and depth into LV
  • Pressure half-time
  • Holodiastolic flow reversal in descending aorta

• Caution with eccentric jets:

  • Thin eccentric jets may lead to underestimation of AR severity, especially in bicuspid valves 1

Left Ventricular Assessment

• LV dimensions:

  • End-diastolic dimension
  • End-systolic dimension
  • For AR: End-systolic dimension >55 mm and fractional shortening <25% identify high-risk patients 3

• LV function:

  • Ejection fraction
  • Longitudinal strain (reduced in severe AS even with preserved EF) 1
  • Assessment of LV hypertrophy and remodeling

Aortic Root and Ascending Aorta Assessment

• Measurements:

  • Annular diameter (measured in systole, from tissue-blood interface to blood-tissue interface) 1
  • Sinus of Valsalva dimensions
  • Sinotubular junction
  • Ascending aorta dimensions

• 3D imaging considerations:

  • 3D TEE may be necessary for accurate annular sizing when TTE measurements are uncertain
  • Critical for TAVI planning and valve sizing 1

Special Considerations

• Prosthetic valve assessment:

  • Evaluation for paravalvular leaks
  • Assessment of leaflet mobility and potential thrombosis
  • Doppler gradients across prosthetic valves (accounting for pressure recovery) 1

• Mixed valve disease:

  • Combined stenosis and regurgitation requires comprehensive assessment
  • Careful evaluation of both components is essential

Technical Pitfalls to Avoid

• Underestimation of gradients:

  • Poor Doppler alignment with flow direction
  • Ensure optimal interrogation angle

• Errors in AVA calculation:

  • Accurate LVOT diameter measurement is critical
  • Use of multiple windows to obtain highest velocities

• Discrepancies between clinical and echo findings:

  • When physical exam suggests severe AS but echo shows mild AS, further evaluation with cardiac catheterization may be required 1
  • Integrate clinical, hemodynamic, and anatomic data to determine if valve obstruction is the cause of symptoms 1

When echocardiographic findings are inconsistent or discordant with clinical presentation, additional imaging modalities such as TEE, CT, CMR, or cardiac catheterization should be considered to confirm the diagnosis and guide appropriate management decisions.