What are the typical aortic biological prosthesis valve performance parameters measured and estimated from a traditional echocardiogram (electrocardiogram)?

Medical Advisory BoardAll articles are reviewed for accuracy by our Medical Advisory Board
Educational purpose only • Exercise caution as content is pending human review
Article Review Status
Submitted
Under Review
Approved

Last updated: August 5, 2025 • View editorial policy

Personalize

Help us tailor your experience

Which best describes you? Your choice helps us use language that's most understandable for you.

Aortic Biological Prosthesis Valve Performance Parameters Measured by Echocardiography

The most important aortic biological prosthesis valve performance parameters measured by echocardiography include effective orifice area (EOA), peak and mean pressure gradients, Doppler velocity index (DVI), and assessment of regurgitation severity, which collectively provide critical information about valve function and hemodynamics.

Structural Assessment Parameters

  • Valve Structure and Motion:

    • Visual assessment of leaflet thickness, calcification, mobility, and opening angle 1
    • Identification of abnormal structures such as thrombus, pannus, or vegetation
    • Normal biological valves should show thin, mobile leaflets with appropriate opening

  • Sewing Ring Position and Stability:

    • Assessment for dehiscence, rocking, or abnormal motion of the prosthetic valve
    • Rocking >40% of the sewing ring circumference suggests severe paravalvular regurgitation 1

Flow-Dependent Parameters

Velocity and Pressure Measurements

  • Peak Velocity (m/s):

    • Measured using continuous wave (CW) Doppler
    • Normal: <3 m/s
    • Possible obstruction: 3-3.9 m/s
    • Significant obstruction: ≥4 m/s 1
    • Requires multiple acoustic windows to capture the highest velocity

  • Mean Pressure Gradient (mmHg):

    • Calculated using the simplified Bernoulli equation (ΔP = 4V²)
    • Normal: <20 mmHg
    • Possible obstruction: 20-34 mmHg
    • Significant obstruction: ≥35 mmHg 1
    • Important caveat: In normally functioning bioprostheses with low velocities (<2 m/s), the simplified Bernoulli equation may overestimate gradients by 13-19% 1

  • Flow Acceleration Dynamics:

    • Acceleration time (AT): Time from onset of flow to maximal velocity
      • Normal: <80 ms
      • Possible obstruction: 80-100 ms
      • Significant obstruction: >100 ms 1
    • AT/Ejection Time ratio:
      • Normal: <0.32
      • Possible obstruction: 0.32-0.37
      • Significant obstruction: >0.37 1
    • Flow envelope shape: Triangular with early peaking in normal valves; rounded and symmetrical in stenotic valves

Flow-Independent Parameters

Effective Orifice Area (EOA) Measurements

  • EOA by Continuity Equation (cm²):

    • Calculated as: Stroke Volume/VTI across prosthesis
    • Formula: EOA = (LVOT area × LVOT VTI)/Prosthetic valve VTI 1
    • Normal: >1.1 cm²
    • Possible obstruction: 0.8-1.1 cm²
    • Significant obstruction: <0.8 cm² 1
    • Critical measurement pitfall: Accurate measurement of LVOT diameter is essential as errors are squared in the calculation 1

  • Indexed EOA (cm²/m²):

    • EOA divided by body surface area
    • Used to identify patient-prosthesis mismatch (PPM)
    • For BMI <30 kg/m²:
      • No PPM: ≥0.85 cm²/m²
      • Moderate PPM: 0.65-0.85 cm²/m²
      • Severe PPM: <0.65 cm²/m² 1

  • Comparison to Reference Values:

    • Measured EOA should be compared to normal reference values for specific valve type and size
    • Difference between reference and measured EOA:
      • Normal: <0.25 cm²
      • Possible obstruction: 0.25-0.35 cm²
      • Significant obstruction: >0.35 cm² 1

  • Doppler Velocity Index (DVI):

    • Ratio of LVOT VTI to prosthetic valve VTI
    • Normal: ≥0.35
    • Possible obstruction: 0.25-0.34
    • Significant obstruction: <0.25 1
    • Advantage: Less dependent on flow conditions than pressure gradients

Regurgitation Assessment Parameters

Central Regurgitation

  • Color Flow Jet Width:

    • Mild: Small jet
    • Moderate: Intermediate jet
    • Severe: Large jet (>65% of LVOT diameter) 1

  • CW Doppler Signal Intensity:

    • Mild: Incomplete or faint signal
    • Moderate/Severe: Dense signal 1
    • Signal contour: Truncated with triangular contour suggests elevated pressure or severe regurgitation

  • Pressure Half-Time (PHT):

    • Mild: >500 ms
    • Moderate: 200-500 ms
    • Severe: <200 ms 1
    • Caution: Intermediate values (200-500 ms) are less specific as they are influenced by heart rate, LV compliance, and acuteness of regurgitation

Paravalvular Regurgitation

  • Circumferential Extent:

    • Mild: <10% of sewing ring circumference
    • Moderate: 10-29%
    • Severe: ≥30% 1

  • Vena Contracta Width:

    • Mild: <3 mm
    • Moderate: 3-6 mm
    • Severe: >6 mm 1
    • Measured using color Doppler with Nyquist limit of 50-60 cm/s

Quantitative Parameters

  • Effective Regurgitant Orifice Area (EROA):

    • Mild: <10 mm²
    • Moderate: 10-29 mm²
    • Severe: ≥30 mm² 1
    • Calculated using PISA method when feasible (more applicable to bioprostheses with central regurgitation)

  • Regurgitant Volume (RVol):

    • Mild: <30 mL
    • Moderate: 30-59 mL
    • Severe: ≥60 mL 1
    • Can be calculated as the difference between LVOT stroke volume and RV stroke volume (if no significant pulmonary regurgitation)

  • Regurgitant Fraction:

    • Mild: <30%
    • Moderate: 30-50%
    • Severe: >50% 1
    • Calculated as regurgitant volume divided by LVOT stroke volume

Downstream Flow Assessment

  • Diastolic Flow Reversal in Descending Aorta:
    • Mild: Brief, early diastolic reversal
    • Moderate: Intermediate
    • Severe: Holodiastolic flow reversal with end-diastolic velocity >20 cm/s 1
    • Caution: Elderly patients with stiff aortas may show holodiastolic flow reversal with only mild AR

Serial Assessment Parameters

  • Change in Mean Gradient During Follow-up:

    • Normal: <10 mmHg increase
    • Possible obstruction: 10-19 mmHg increase
    • Significant obstruction: ≥20 mmHg increase 1

  • Change in EOA During Follow-up:

    • A decrease in EOA >25% suggests clinically significant obstruction 1

Practical Considerations and Pitfalls

  1. Acoustic Shadowing: Prosthetic valve materials can create shadowing that impairs visualization of leaflets and flow patterns, particularly for paravalvular regurgitation assessment

  2. Pressure Recovery Phenomenon: Doppler may overestimate gradients compared to catheter measurements, especially in patients with small aortas 1

  3. LVOT Diameter Measurement: Critical for accurate EOA calculation; errors are squared in the continuity equation. Be careful not to mistake the inner border of the prosthesis stent/ring for the LVOT edge 1

  4. Flow Dependence: Pressure gradients are highly flow-dependent; low-flow states may mask significant stenosis while high-flow states may exaggerate gradients in normal valves

  5. Reference Values: EOA values must be compared to normal reference values for the specific prosthesis type and size, as there is significant variation between different valve models 1

References

1
Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

Related Questions

How is stress-induced hypercholesterolemia (elevated cholesterol) treated?
What is the recommended use of enoxaparin (low molecular weight heparin) in acute coronary syndrome?
What is the recommended dosing of bisphosphonates (e.g. zoledronic acid, pamidronate) for treating hypercalcemia of unknown etiology?
What is the typical duration of treatment with Provera (medroxyprogesterone) for abnormal uterine bleeding?
What is the recommended frequency of pamidronate (Pamidronate) for hypercalcemia of malignancy?
What is the recommended course of action if low back pain persists beyond 2 weeks?

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

Have a follow-up question?

Our Medical A.I. is used by practicing medical doctors at top research institutions around the world. Ask any follow up question and get world-class guideline-backed answers instantly.

Ask Question