From the Guidelines
When investigating mitral inflow with pulse wave Doppler in mitral valve infective endocarditis, you would expect to see several abnormal findings, most notably mitral regurgitation, characterized by a high-velocity retrograde flow from the left ventricle into the left atrium during systole, as supported by the most recent evidence from 1 and 1.
Expected Abnormal Findings
The severity of regurgitation can range from mild to severe depending on the extent of valve damage. You might observe:
- Increased E-wave velocity (early diastolic filling) and a decreased E/A ratio if the infection has caused significant valvular destruction.
- Vegetation-related obstruction may produce increased transvalvular gradients with elevated peak and mean diastolic velocities across the mitral valve.
- In cases with large vegetations or valve perforation, you may see abnormal flow acceleration and turbulence around the valve.
- Diastolic mitral valve prolapse might be evident if the infection has damaged the valve leaflets or chordae tendineae. These findings occur because infective endocarditis causes structural damage to the valve through vegetation formation, leaflet perforation, or destruction of supporting structures, all of which disrupt normal blood flow patterns through the valve.
Clinical Implications
The size and other characteristics of vegetations on echocardiography have been shown to be useful in predicting complications such as peripheral embolization 1. Other echocardiographic findings that can guide prognosis include periannular complications, severe valvular regurgitation, low ejection fraction, pulmonary hypertension, severe prosthetic valve dysfunction, and premature mitral valve closure (a sign of elevated diastolic pressures) 1.
Diagnostic Approach
Echocardiography, particularly transesophageal echocardiography (TEE), is a crucial tool in the diagnosis and management of infective endocarditis, as it provides detailed images of the heart valves and surrounding structures, helping to identify vegetations, abscesses, and other complications 1. Transthoracic echocardiography (TTE) may also be used, especially in cases where TEE is not immediately available or in small children 1.
Prognostic Value
In left-sided native valve S. aureus endocarditis, the presence of an intracardiac abscess and left ventricular ejection fraction <40% on echocardiography have been shown to be independent predictors of in-hospital mortality, and intracardiac abscess and valve perforation on echocardiography have been shown to be independent predictors of 1-year mortality 1.
From the Research
Abnormal Findings on TTE
When investigating the mitral inflow with pulse wave Doppler in a case of mitral valve infective endocarditis, the following abnormal findings can be expected:
- Mitral stenosis: Infective endocarditis can cause mitral valve stenosis, which can be detected on TTE as an increased pressure gradient across the mitral valve 2
- Mitral regurgitation: Severe mitral regurgitation can occur due to mitral valve perforation or destruction of the valve leaflets, which can be visualized on TTE as a high-velocity jet of blood flowing backward from the left ventricle into the left atrium 3, 4
- Abnormal mitral valve motion: Infective endocarditis can cause destruction of the mitral valve leaflets or chordae tendineae, leading to abnormal mitral valve motion, which can be detected on TTE as an irregular or chaotic pattern of valve movement 5
Doppler Findings
On pulse wave Doppler, the following abnormal findings can be expected:
- Increased E-wave velocity: Mitral stenosis can cause an increased E-wave velocity, which can be detected on pulse wave Doppler as a high-velocity signal during early diastole 2
- Increased pressure gradient: Mitral stenosis can also cause an increased pressure gradient across the mitral valve, which can be detected on pulse wave Doppler as a high-velocity signal during diastole 2
- Regurgitant jet: Severe mitral regurgitation can cause a regurgitant jet, which can be detected on pulse wave Doppler as a high-velocity signal flowing backward from the left ventricle into the left atrium 3, 4