Prosthetic Valves

Evaluation requires the prosthesis type, size, position, implantation date, and comparison with the baseline postoperative study.

Normal velocities and gradients vary by valve design and size. A high gradient does not necessarily indicate obstruction.

Routine Assessment¶

Report:

Valve type and position
Leaflet or occluder motion when visible
Peak velocity and mean gradient
Heart rate for mitral and tricuspid prostheses
Effective orifice area (EOA)
Doppler velocity index (DVI)
Location and severity of regurgitation
Ventricular size and function
Pulmonary pressure
Change from baseline

Compare measurements obtained under similar heart rate, rhythm, blood pressure, and flow conditions.

Causes of Prosthetic Valve Dysfunction¶

Cause	Typical findings
Structural valve deterioration	Calcification, thickening, tear, prolapse, or restricted bioprosthetic leaflets
Thrombus	Acute or subacute dysfunction; soft mass or restricted leaflet motion
Pannus	Gradual obstruction from periannular fibrous tissue
Endocarditis	Vegetation, paravalvular leak, dehiscence, abscess, or fistula
Prosthesis-patient mismatch	High gradient with normal valve structure and motion
Paravalvular leak	Regurgitation outside the sewing ring or transcatheter frame
High-flow state	Increased velocity and gradient with preserved DVI and EOA

Mechanical valves normally demonstrate small closing and washing jets. These should not be mistaken for pathologic regurgitation.

Prosthetic Aortic Valve¶

Obtain CW Doppler from multiple windows and use the highest reproducible velocity.

\[ DVI = \frac{VTI_{LVOT}} {VTI_{Prosthetic\ AV}} \]

Parameter	Normal	Possible stenosis	Significant stenosis
Peak velocity	<3 m/s	3–4 m/s	≥4 m/s
Mean gradient: SAVR	<20 mm Hg	20–34 mm Hg	≥35 mm Hg
DVI	>0.35	0.25–0.35	<0.25
Acceleration time	<80 ms	80–100 ms	>100 ms
AT/ejection time	<0.32	0.32–0.37	>0.37
Jet contour	Triangular, early peak	Intermediate	Rounded, symmetric

Significant stenosis should include at least:

One flow-dependent abnormality: velocity or gradient
One flow-independent abnormality: DVI or EOA

An elevated gradient with normal DVI, normal acceleration time, and an early-peaking contour favors high flow or prosthesis-patient mismatch rather than obstruction.

Aortic Prosthesis-Patient Mismatch¶

Use indexed EOA:

BMI	Moderate PPM	Severe PPM
<30 kg/m²	0.66–0.85 cm²/m²	≤0.65 cm²/m²
≥30 kg/m²	0.56–0.70 cm²/m²	≤0.55 cm²/m²

PPM is present from implantation and should not cause a progressive decline in leaflet motion or EOA.

Prosthetic Mitral Valve¶

Report the heart rate with all transmitral gradients.

Unlike the aortic DVI, the mitral DVI places the prosthetic valve VTI in the numerator:

\[ DVI = \frac{VTI_{Prosthetic\ MV}} {VTI_{LVOT}} \]

Parameter	Normal	Possible stenosis	Significant stenosis
Peak velocity	<1.9 m/s	1.9–2.5 m/s	≥2.5 m/s
Mean gradient	≤5 mm Hg	6–10 mm Hg	>10 mm Hg
DVI	<2.2	2.2–2.5	>2.5
EOA	≥2.0 cm²	1.0–2.0 cm²	<1.0 cm²
Pressure half-time	<130 ms	130–200 ms	>200 ms

Pressure half-time is affected by heart rate and atrioventricular compliance and should not be used alone.

A high mitral gradient may result from:

Tachycardia
Significant prosthetic MR
High cardiac output
Prosthesis-patient mismatch
True obstruction

TTE may miss prosthetic MR because of acoustic shadowing. Supporting findings include:

Dense CW MR signal
Large systolic flow convergence
Pulmonary vein systolic flow reversal
Hyperdynamic LV with low LVOT stroke volume
DVI >2.5
Unexplained pulmonary hypertension

TEE is usually required when clinically important prosthetic MR is suspected.

Prosthetic Tricuspid Valve¶

Record the mean gradient over multiple respiratory cycles and report the heart rate.

A mean gradient <6 mm Hg generally supports normal mechanical tricuspid prosthesis function. Gradients are affected by respiration, valve size, heart rate, and cardiac output.

A post–valve-in-valve or valve-in-ring mean gradient >10 mm Hg supports stenosis.

Prosthetic Regurgitation¶

Determine whether regurgitation is:

Transvalvular
Paravalvular
Physiologic or pathologic

Rocking or excessive motion of the prosthesis suggests dehiscence. New paravalvular regurgitation should raise concern for endocarditis, suture disruption, or annular pathology.

For aortic paravalvular regurgitation, a circumferential extent ≥30% supports severe regurgitation, but circumferential extent should not be used alone.

Thrombus Versus Pannus¶

Feature	Thrombus	Pannus
Timing	Often early or abrupt	Usually gradual and delayed
Anticoagulation	Often inadequate	Usually therapeutic
Appearance	Larger, softer mass	Small, dense periannular tissue
Location	Either side of valve	Commonly ventricular side of aortic prosthesis
CT attenuation	Lower	Higher
Treatment response	May improve with anticoagulation	Does not resolve with anticoagulation

TEE evaluates masses and regurgitation. CT is particularly useful for leaflet motion, thrombus, pannus, and transcatheter leaflet thickening. Fluoroscopy evaluates mechanical leaflet opening and closing angles.

Suggested Reporting¶

The ___ mm ___ prosthesis is well seated with normal leaflet/occluder motion. Peak velocity is ___ m/s, mean gradient is ___ mm Hg, DVI is ___, and calculated EOA is ___ cm². No significant transvalvular or paravalvular regurgitation is present.

The prosthetic aortic valve demonstrates elevated velocity and gradient with prolonged acceleration time and reduced DVI, concerning for prosthetic valve obstruction.

The prosthetic mitral valve demonstrates a mean gradient of ___ mm Hg at a heart rate of ___ bpm. Findings are consistent with significant prosthetic mitral stenosis.

The prosthesis is well seated with elevated gradients but preserved leaflet motion, DVI, and EOA. Findings favor prosthesis-patient mismatch rather than obstruction.

There is abnormal rocking of the prosthesis with significant paravalvular regurgitation, concerning for prosthetic dehiscence.

Key Points¶

Always compare with the baseline postoperative study.
Aortic DVI decreases with obstruction; mitral DVI increases.
Diagnose obstruction using both flow-dependent and flow-independent parameters.
Report heart rate with mitral and tricuspid gradients.
PPM produces high gradients despite normal valve structure and motion.
Mechanical valves normally have small washing jets.
Use TEE, CT, or fluoroscopy when TTE cannot define the mechanism.