📚 Guideline basis
Zoghbi WA, Jone PN, Chamsi-Pasha MA, et al. Guidelines for the Evaluation of Prosthetic Valve Function With Cardiovascular Imaging: A Report From the American Society of Echocardiography, Developed in Collaboration With SCMR and SCCT. J Am Soc Echocardiogr 2024;37:2–63. This document replaces the 2009 ASE prosthetic valve guideline and complements the ASE 2019 guideline on regurgitation after percutaneous valve repair or replacement. Also: Lancellotti P, et al., EACVI recommendations for imaging assessment of prosthetic heart valves (EHJCI 2016, PMID 26715985); 2025 ESC/EACTS valvular heart disease guidelines.
The three questions
Prosthetic valve assessment in the ICU answers three questions in order:
- Is the gradient elevated, and if so, is the cause obstruction, patient–prosthesis mismatch, or high flow?
- Is there pathological regurgitation, and is it transvalvular or paravalvular?
- Is there a structural cause — thrombus, pannus, vegetation, dehiscence — and does it require intervention?
Answering them requires knowing the type, size and implant date of the prosthesis. Without these, no gradient can be interpreted, because normal values are prosthesis- and size-specific. A prior baseline study is the single most valuable comparator, and its absence is the commonest reason a prosthetic assessment is inconclusive.
Prosthesis types and expected haemodynamics
Type | Occluder | Notes |
Bileaflet mechanical (St Jude, Carbomedics, On-X) | Two semicircular discs | Most commonly implanted mechanical valve; best mechanical haemodynamics. Normal opening angle 73–90° |
Single tilting disc (Medtronic-Hall, Björk-Shiley) | One disc | Infrequent in contemporary practice. Normal opening angle 60–80° |
Ball-in-cage (Starr-Edwards) | Silastic ball | No longer implanted; durable survivors still encountered |
Stented bioprosthesis | Porcine or bovine pericardial leaflets on a stent | Most common surgical tissue valve |
Stentless bioprosthesis / homograft / autograft | No stent frame | Larger areas, lower gradients, but higher early structural valve dysfunction rates in younger patients |
Transcatheter (TAVI) | Balloon-expandable intra-annular (SAPIEN) or self-expanding supra-annular (Evolut) | Supra-annular designs give larger EOA and lower gradients |
Mechanical mitral prostheses: normal EOA 2–3 cm², mean gradient 2–3 mmHg (up to 5–6 mmHg in smaller valves at physiological heart rates). Bioprosthetic mitral: EOA 2.2–3.5 cm², mean gradient 3–5 mmHg.
Physiological ("washing") regurgitation
Mechanical valves are designed to leak. Two components exist: a closing volume (retrograde displacement as the occluder shuts) and true small transvalvular jets at the hinge points, intended to prevent stasis and thrombus.
Valve | Pattern |
Bileaflet | Multiple jets just inside the sewing ring where leaflets meet the housing, plus central jets at leaflet apposition — typically two from each pivot, sometimes dividing into two or three plumes |
Single tilting disc (Björk-Shiley) | Small jets where the closed disc meets the housing |
Medtronic-Hall | Those jets plus a single larger central jet through the disc pivot hole |
Starr-Edwards | Small closing volume, little or no true transvalvular regurgitation |
Physiological jets are low-momentum, homogeneous in colour with aliasing confined to the base, narrow at origin, and symmetric. The regurgitant fraction is typically no more than 10–15%, though the colour jet may extend up to 5 cm (particularly in Medtronic-Hall valves). Mistaking a normal washing jet for pathology is a common error; mistaking a pathological jet for a washing jet is the dangerous one.
Diagnostic Synthesis — prosthetic aortic valve
Doppler criteria (ASE 2024, Table 5)
Applicable to all prosthetic aortic valves:
Parameter | Normal | Possible stenosis | Suggests significant stenosis |
Jet velocity contour | Triangular, early-peaking | Triangular to intermediate | Rounded, symmetric |
Acceleration time, ms | < 80 | 80–100 | > 100 |
AT / LV ejection time | < 0.32 | 0.32–0.37 | > 0.37 |
Peak velocity, m/s | < 3 | 3–4 | ≥ 4 |
Specific to surgical aortic valve replacement:
Parameter | Normal | Possible stenosis | Significant stenosis |
Mean gradient, mmHg | < 20 | 20–34 | ≥ 35 |
Doppler velocity index (VTI_LVOT / VTI_PrAV) | > 0.35 | 0.25–0.35 | < 0.25 |
EOA | Reference EOA ± 1 SD | 1 SD below reference | 2 SD below reference |
For TAVI, criteria are expressed as change from the post-procedural baseline: mean gradient increase ≥ 20 mmHg, DVI decrease ≥ 0.2 or ≥ 40%, or EOA decrease ≥ 0.6 cm² or ≥ 50% suggests significant stenosis.
The ASE 2024 rule: significant stenosis requires at least one flow-dependent parameter (peak velocity, mean gradient) AND one flow-independent parameter (EOA or DVI). A high gradient alone never establishes obstruction.
Structural valve deterioration (ASE 2024, Table 6)
Possible SVD | Significant SVD |
Mean gradient increase ≥ 10 mmHg to a gradient ≥ 20 mmHg, with EOA decrease ≥ 0.3 cm² or ≥ 25% and/or DVI decrease ≥ 0.1 or ≥ 20% versus the 1–3 month post-procedural baseline | Mean gradient increase ≥ 20 mmHg to a gradient ≥ 30 mmHg, with EOA decrease ≥ 0.6 cm² or ≥ 50% and/or DVI decrease ≥ 0.2 or ≥ 40% versus baseline |
New or ≥ 1-grade increase in intraprosthetic AR resulting in moderate or greater AR | New or ≥ 2-grade increase in intraprosthetic AR resulting in moderate-to-severe or severe AR |
Criteria assume stable LV function and blood pressure, and morphological changes to the prosthesis should be evident.
Patient–prosthesis mismatch (ASE 2024, Table 7)
Indexed EOA, with normal leaflet structure and motion:
Position | Normal | Moderate | Severe |
Aortic, BMI < 30 | > 0.85 cm²/m² | 0.85–0.66 | ≤ 0.65 |
Aortic, BMI ≥ 30 | > 0.70 cm²/m² | 0.70–0.56 | ≤ 0.55 |
Mitral, BMI < 30 | > 1.2 cm²/m² | 1.2–0.91 | ≤ 0.90 |
Mitral, BMI ≥ 30 | > 1.0 cm²/m² | 1.0–0.76 | ≤ 0.75 |
PPM is a normally functioning valve that is too small for the patient. It is distinguished from obstruction by normal leaflet motion, a measured EOA within 1 SD of the reference value for that prosthesis type and size, and — crucially — an elevated gradient that was present on the baseline post-operative study. This is why the baseline study matters.
Diagnostic Synthesis — prosthetic mitral valve
Criteria for significant prosthetic mitral stenosis (ASE 2024):
- Mean gradient > 10 mmHg at a normal heart rate
- Pressure half-time > 200 ms
- DVI (VTI_PrMV / VTI_LVOT) > 2.5
- EOA < 1 cm²
Note the DVI is inverted relative to the aortic position. In one comparative study it was the most sensitive and specific single Doppler parameter for mitral prosthetic stenosis.
EOA = SV_LVOT / VTI_PrMV (valid only in the absence of significant AR)Do not use pressure half-time to calculate EOA for a prosthetic mitral valve — ASE 2024 states this is frequently inaccurate and overestimates EOA, particularly in normally functioning valves.
Indirect signs of significant prosthetic mitral regurgitation
Because acoustic shadowing makes direct visualisation of prosthetic MR unreliable on TTE, ASE 2024 lists indirect indicators:
- A dense CW mitral regurgitant jet
- Mitral E velocity > 1.9 m/s in mechanical valves
- Low systemic output and low LVOT VTI despite a hyperdynamic left ventricle
- VTI_PrMV / VTI_LVOT > 2.5
- A large systolic flow convergence zone on the LV side of the prosthesis
- A significant rise in pulmonary artery pressure compared with a previous study
Any of these mandates TEE.
Prosthetic aortic regurgitation severity (ASE 2024, Table 8)
Parameter | Mild | Moderate | Severe |
Jet width / LVOT diameter, % | ≤ 25 | 26–64 | ≥ 65 |
Vena contracta width, cm | < 0.3 | 0.3–0.6 | > 0.6 |
Vena contracta area, cm² (2D/3D) | < 0.10 | 0.10–0.29 | ≥ 0.30 |
Circumferential extent of paravalvular leak, % | < 10 | 10–29 | ≥ 30 |
CW jet density | Incomplete or faint | Dense | Dense |
Pressure half-time, ms | > 500 | 200–500 | < 200 |
Descending aortic diastolic reversal | Absent or brief early | Intermediate | Prominent, holodiastolic |
Regurgitant volume, mL | < 30 | 30–59 | ≥ 60 |
Regurgitant fraction, % | < 30 | 30–50 | ≥ 50 |
Circumferential extent is measured as the sum of the circumferential lengths of each regurgitant jet's vena contracta (excluding the non-regurgitant space between jets) divided by the outer circumference of the valve, and ASE advises against using it alone.
Obstruction: thrombus versus pannus
Feature | Thrombus | Pannus |
Timing after implant | Early or any time; often with subtherapeutic anticoagulation | Late (years) |
Prevalence | 0.3–8% of prosthetic valves; the tricuspid position is affected 12–20 times more often than left-sided valves | 0.2–4.5%; three times higher risk in the mitral position |
Echodensity | Soft, lower density, often mobile, larger | Firm, echodense, immobile, smaller, at the periannular region |
Typical location (aortic prosthesis) | Aortic side | Ventricular side |
CT attenuation | < 200 HU; a cutoff of 145 HU distinguishes thrombus from pannus with 87.5% sensitivity and 96% specificity | > 200 HU |
Response to anticoagulation/lysis | Responds; complete lysis is more likely at attenuation < 90 HU than 90–145 HU | Does not respond |
Definitive management | Anticoagulation, thrombolysis, or surgery | Surgery |
Pannus and thrombus frequently coexist. Cardiac CT is the discriminating modality and should be requested when the mechanism will change management. Cine fluoroscopy remains useful for demonstrating restricted mechanical leaflet motion when echocardiography cannot.
Hypoattenuated leaflet thickening (HALT) with or without hypoattenuation affecting motion (HAM) is a CT diagnosis, seen after TAVI and surgical bioprostheses, frequently associated with a rise in gradient, and often reversible with anticoagulation.
Paravalvular versus transvalvular regurgitation
Transvalvular | Paravalvular | |
Jet origin | Within the sewing ring or stent | Outside the sewing ring, between prosthesis and annulus |
Mechanism | Leaflet degeneration, perforation, occluder malfunction | Dehiscence, incomplete apposition, endocarditis, calcification, undersizing |
Additional signs | — | Rocking motion of the prosthesis (> 15° excursion) indicates significant dehiscence |
Associated | SVD | Haemolysis, endocarditis |
Modality | TTE may suffice for aortic; TEE for mitral | Multiple off-axis windows; 3D TEE en face is the reference for localisation |
Dehiscence requiring reintervention affects approximately 4.9% of aortic and 2.0% of mitral prosthetic valves. Small paravalvular jets are present in 5–20% immediately after implantation and, in the absence of endocarditis, most follow a benign course.
The acoustic shadowing problem
This governs modality selection and is the single most important practical point in the chapter.
Position | TTE limitation | Consequence |
Mitral prosthesis | The prosthesis is in the near field from the apical window and shadows the entire left atrium behind it | TTE cannot exclude prosthetic mitral regurgitation. TEE is mandatory. The parasternal window is often best for jet detection on TTE |
Aortic prosthesis | Shadowing obscures the posterior annulus and root from TTE | TEE visualises the posterior root well but has its own anterior blind spot; the two are complementary |
Both | Reverberation obscures leaflet/occluder motion | CT or fluoroscopy when motion cannot be determined and obstruction is suspected |
ICU-Specific Limitations
Confounder | Effect | Response |
High output (sepsis, anaemia, fever) | Raises gradients across a normal prosthesis | Use EOA and DVI (flow-independent); state the flow state |
Tachycardia | Raises mitral and tricuspid prosthetic gradients steeply | Report heart rate with every prosthetic gradient |
Low output | Masks true obstruction | Flow-independent parameters; consider CT |
Small bileaflet aortic prostheses (e.g. 19 mm) with high flow | Pressure recovery within the central orifice inflates Doppler gradients relative to catheter | Evaluate leaflet motion by TEE, CT or fluoroscopy before diagnosing obstruction |
Missing baseline study | PPM cannot be distinguished from new obstruction | Compare to reference tables for that prosthesis type and size |
Unknown valve type/size | No normal values apply | Obtain the operation note or valve card before reporting |
Ventilated, post-sternotomy | Poor TTE windows | Early TEE |
Therapeutic Logic
Finding | Action |
Obstructive thrombus, left-sided, with haemodynamic compromise | Emergency surgery or thrombolysis per Heart Team and institutional protocol; CT attenuation informs the likelihood of lysis success |
Obstructive thrombus, small, non-obstructive, or right-sided | Intensified anticoagulation with serial imaging |
Pannus | Surgical reintervention |
Severe paravalvular leak with heart failure or haemolysis | Percutaneous closure or surgery |
Dehiscence with rocking prosthesis | Assume endocarditis until excluded; surgical referral |
Structural valve deterioration | Redo surgery or valve-in-valve TAVI |
Patient–prosthesis mismatch | No acute intervention; rate control, afterload management, avoid attributing decompensation to it without excluding other causes |
🛑 Critical pitfall: Reporting "prosthesis functioning normally, no significant regurgitation" from a transthoracic study of a mitral prosthesis. Acoustic shadowing makes this a statement TTE cannot support. Say instead: "prosthetic mitral regurgitation not excluded; TEE required."
🛑 Critical pitfall: Diagnosing prosthetic obstruction from an elevated gradient alone in a septic, tachycardic, high-output patient. Flow is the likelier explanation. Require a flow-independent parameter.
🛑 Critical pitfall: Attributing a high gradient to patient–prosthesis mismatch without a baseline study. PPM is present from the day of implantation; a gradient that has risen is not PPM.
- 💡 Clinical pearl: Get the valve card, the operation note, and the last echocardiogram before interpreting anything. Normal values are prosthesis-specific and the trajectory matters more than the absolute number.
- 💡 Clinical pearl: Acceleration time > 100 ms and a rounded, symmetric, late-peaking aortic prosthetic envelope are pattern-recognition signs of obstruction visible before any measurement.
- 💡 Clinical pearl: A mitral prosthetic E velocity > 1.9 m/s with a low LVOT VTI and a hyperdynamic ventricle is a strong indirect signature of significant prosthetic MR — request TEE.
- 💡 Clinical pearl: Right-sided prosthetic valves thrombose 12–20 times more often than left-sided ones. In a tricuspid prosthesis with a rising gradient, thrombus is the leading diagnosis.
References
- Zoghbi WA, Jone PN, Chamsi-Pasha MA, et al. Guidelines for the evaluation of prosthetic valve function with cardiovascular imaging: a report from the American Society of Echocardiography. J Am Soc Echocardiogr 2024;37:2–63. doi:10.1016/j.echo.2023.10.004
- Zoghbi WA, Asch FM, Bruce C, et al. Guidelines for the evaluation of valvular regurgitation after percutaneous valve repair or replacement. J Am Soc Echocardiogr 2019;32:431–75.
- Lancellotti P, Pibarot P, Chambers J, et al. Recommendations for the imaging assessment of prosthetic heart valves. Eur Heart J Cardiovasc Imaging 2016. PMID 26715985.
- Zoghbi WA, Chambers JB, Dumesnil JG, et al. Recommendations for evaluation of prosthetic valves. J Am Soc Echocardiogr 2009;22:975–1014. PMID 19228817. — superseded by ref 1
- ESC/EACTS. 2025 Guidelines for the management of valvular heart disease. Eur Heart J 2025;46:4635–.