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Echo Reference — Prosthetic Valves

Prosthetic Valve Assessment

Doppler parameters for prosthetic aortic, mitral, tricuspid, and pulmonary valves. Prosthesis–patient mismatch thresholds, elevated gradient algorithms, DVI decision pathways, and paravalvular regurgitation grading.

Algorithms Reference Tables

Prosthetic Aortic Valve — Doppler Parameters

Prosthetic valve Doppler parameters vary significantly by valve type, size, and manufacturer. A single baseline postoperative echo (ideally 6 weeks to 3 months after surgery) is essential for establishing individual reference values. Subsequent studies should be compared to this baseline. The values below are general guidelines — always check manufacturer-specific reference tables.
Parameter Normal Possible Stenosis Significant Stenosis
Peak velocity (m/s)† < 3 3 – 4 > 4
Mean gradient (mmHg)† < 20 20 – 35 ≥ 35
DVI (LVOT VTI ÷ AV VTI) ≥ 0.35 0.25 – 0.35 < 0.25
EOA (cm²) Reference EOA ± 1 SD 1 SD < reference EOA 2 SD < reference EOA
Acceleration time (ms) < 80 80 – 100 > 100
Jet contour Triangular, early peaking Triangular to intermediate Rounded, symmetrical

†These parameters are more affected by flow, including concomitant AR. Values assume normal or near-normal stroke volume (50–90 mL).

Prosthesis–Patient Mismatch — AVR

PPM occurs when the effective orifice area of the prosthesis, indexed to BSA, is too small for the patient's body size. It results in higher-than-expected gradients despite a normally functioning prosthesis.

AVR PPM No PPM Moderate Severe
iEOA (cm²/m²) — BMI < 30 > 0.85 0.65 – 0.85 < 0.65
iEOA (cm²/m²) — BMI ≥ 30 > 0.70 0.56 – 0.70 ≤ 0.55

Elevated Gradient Algorithm — Prosthetic AVR

When the mean gradient across a prosthetic aortic valve is higher than expected, a systematic approach is required to differentiate intrinsic prosthetic dysfunction from extrinsic causes of elevated gradients.

Step Action
1. Compare to baseline Is the gradient significantly increased from the early postoperative baseline? If unchanged → likely PPM or normal for valve type/size. If increased → investigate further.
2. Calculate DVI DVI = LVOT VTI ÷ prosthetic AV VTI. DVI < 0.25 → suggests intrinsic obstruction (pannus, thrombus, SVD). DVI ≥ 0.35 → high gradient is likely from high flow, not obstruction. DVI 0.25–0.35 → borderline, investigate further.
3. Assess flow state Calculate SV and SVi. High-output states (anaemia, fever, anxiety, sepsis, significant AR) increase gradients without obstruction. Correct for flow before diagnosing dysfunction.
4. Check for PPM Calculate indexed EOA. If iEOA < 0.85 cm²/m² and gradient is elevated but DVI is normal → PPM is the explanation.
5. Structural assessment Leaflet thickening, calcification, or restricted motion (bioprosthetic SVD). Pannus or thrombus (mechanical valves — TOE may be needed). Paravalvular leak. Fluoroscopy for mechanical disc motion.
6. Acceleration time AT > 100 ms suggests significant obstruction (valve opening is impaired). AT/ET ratio > 0.37 is an additional marker.
Bioprosthetic SVD: Structural valve deterioration in bioprosthetic AVR typically presents as progressive stenosis (leaflet thickening, calcification), regurgitation (leaflet tear, calcific perforation), or both. A new mean gradient increase of > 10 mmHg from baseline, or a new gradient ≥ 20 mmHg with DVI < 0.25, should raise suspicion. The VARC-3 consensus defines clinically significant SVD as a mean gradient increase ≥ 10 mmHg with morphological abnormality.

Prosthetic Mitral Valve — Doppler Parameters

Parameter Normal Possible Stenosis Significant Stenosis
Peak velocity (m/s)† < 1.9 1.9 – 2.5 > 2.5
Mean gradient (mmHg)† ≤ 5 6 – 10 > 10
MVR Index (DVI)† < 2.2 2.2 – 2.5 > 2.5
EOA (cm²) ≥ 2.0 1.0 – 2.0 < 1.0
PHT (ms) < 130 130 – 200 > 200

†These parameters are also abnormal in the presence of significant prosthetic MR. Slightly higher cutoffs may be seen in some bioprosthetic valves.

Prosthesis–Patient Mismatch — MVR

MVR PPM No PPM Moderate Severe
iEOA (cm²/m²) — BMI < 30 > 1.2 0.91 – 1.2 ≤ 0.91
iEOA (cm²/m²) — BMI ≥ 30 > 1.0 0.76 – 1.0 ≤ 0.75

Prosthetic MVR Dysfunction — DVI Approach

For mechanical mitral valves, the DVI compares mitral prosthetic VTI to LVOT VTI. An elevated DVI (> 2.2 for bileaflet mechanical valves) suggests obstruction. For bioprosthetic MVR, elevated mean gradient (> baseline + 5 mmHg) with prolonged PHT (> 130 ms) suggests stenotic dysfunction.

Finding Interpretation
Elevated mean gradient + prolonged PHT Suggests obstruction (thrombus, pannus, SVD). Compare to baseline. TOE recommended.
Elevated mean gradient + normal/short PHT High flow state (significant MR, high output, tachycardia). PHT not prolonged because stenosis is not the issue.
Normal gradient + new/worsening MR Regurgitant dysfunction — leaflet tear, paravalvular leak, or disc malfunction. TOE essential.
Washing jets: Mechanical mitral valves have physiological "washing jets" — small, brief regurgitant jets designed to prevent thrombus formation. These are normal and should not be classified as pathological MR. Pathological MR through a mechanical valve appears as a larger, broader jet originating from the occluder mechanism or from outside the sewing ring (paravalvular).

Prosthetic Tricuspid & Pulmonary Valves

Prosthetic Tricuspid Valve — Upper Limits of Normal

Parameter Bioprosthetic TVR Mechanical TVR
Peak velocity (m/s)† ≤ 2.1 ≤ 1.9
Mean gradient (mmHg)† ≤ 9 ≤ 6
PHT (ms) ≤ 200 ≤ 130
EOA (cm²) ≥ 1.5 ≥ 2.0
DVI (prosthetic TV VTI ÷ LVOT VTI) ≤ 3.3 ≤ 2.1

†May be increased with valvular regurgitation. Average ≥ 5 cycles due to respiratory variation. DVI assessed in the absence of AR or TR.

Prosthetic Pulmonary Valve — Upper Limits of Normal

Parameter Bioprosthetic PVR Homograft PVR
Peak velocity (m/s)† ≤ 3.2 ≤ 2.5
Mean gradient (mmHg)† ≤ 20 ≤ 15

Measurements assume normal RV stroke volume. Off-axis views may be needed due to prosthesis position.

Right-sided prostheses: The low-pressure right heart circuit means even mild prosthetic obstruction can be haemodynamically significant. Always assess for RA dilatation, IVC congestion, hepatic vein flow reversal, and clinical signs of right heart failure. For prosthetic PVR (especially in repaired congenital heart disease), CMR provides complementary RV volume assessment.

Paravalvular Regurgitation — Semi-Quantification

Paravalvular leak (PVL) originates from outside the sewing ring, between the prosthesis and the native annulus. It is distinguished from transvalvular regurgitation by jet origin on colour Doppler. TOE is usually required for accurate localisation and grading. PVL is described by location (using the clock-face convention in the short-axis view) and circumferential extent.

Severity Circumferential Extent Additional Features
Mild < 10% of sewing ring Thin jet, narrow vena contracta, no haemodynamic consequence
Moderate 10 – 29% of sewing ring Broader jet, may cause haemolysis. Intermediate vena contracta.
Severe ≥ 30% of sewing ring Wide jet, rocking motion of prosthesis (dehiscence), haemolysis common, volume loading of receiving chamber
Clock-face localisation: In the TOE short-axis view (for mitral prostheses) or TTE parasternal short-axis (for aortic prostheses), describe the PVL location as a clock position (e.g. "paravalvular leak at 10 o'clock, extending from 9 to 11 o'clock"). This is essential for planning percutaneous PVL closure and for surgical re-intervention.
Haemolysis: Even small paravalvular leaks can cause clinically significant haemolysis if the jet is high-velocity and strikes a cardiac structure (mechanical fragmentation of red cells). Suspect haemolysis when LDH is elevated, haptoglobin is low, and schistocytes are present — even if the PVL appears echocardiographically mild. The severity of haemolysis does not always correlate with the volume of regurgitation.

References

  1. Zoghbi WA, et al. Recommendations for Evaluation of Prosthetic Valves With Echocardiography and Doppler Ultrasound. J Am Soc Echocardiogr. 2009;22(9):975–1014.
  2. Lancellotti P, et al. Recommendations for the Imaging Assessment of Prosthetic Heart Valves: A Report from the EACVI. Eur Heart J Cardiovasc Imaging. 2016;17(6):589–590.
  3. Otto CM, et al. 2020 ACC/AHA Guideline for the Management of Patients With Valvular Heart Disease. Circulation. 2021;143(5):e72–e227.
  4. VARC-3 Writing Committee. Updated Standardized Endpoint Definitions for Transcatheter Aortic Valve Implantation. J Am Coll Cardiol. 2021;77(5):645–655.
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