From the Guidelines
Aortic valve vegetations are typically found on the ventricular side of the aortic valve leaflets. This location preference occurs because vegetations tend to form on the low-pressure side of the valve, where blood flow creates more turbulence and allows for bacterial adherence. When the aortic valve closes during diastole, the ventricular surface experiences lower pressure compared to the aortic side, creating conditions favorable for vegetation formation. The high-velocity jet of blood flowing across the valve during systole creates shear forces that can damage the endothelium on the ventricular surface, providing a nidus for platelet and fibrin deposition, which subsequently allows bacteria to adhere and colonize. According to the 2015 ESC guidelines for the management of infective endocarditis 1, perivalvular extension of IE is the most frequent cause of uncontrolled infection and is associated with a poor prognosis and high likelihood of the need for surgery. Key points to consider include:
- Perivalvular abscess is more common in aortic IE and is frequent in PVE
- In aortic IE, perivalvular extension occurs most frequently in the mitral-aortic intervalvular fibrosa
- Serial echocardiographic studies have shown that abscess formation is a dynamic process, starting with aortic root wall thickening and extending to the development of fistulae. This pattern is consistent with the pathophysiology of infective endocarditis, where damaged valvular surfaces become susceptible to bacterial colonization, particularly in areas of turbulent blood flow.
From the Research
Aortic Valve Vegetations
- Aortic valve vegetations are typically localized on the flow side of the valves or at damaged valvular endothelium 2
- However, there have been rare cases reported where the vegetation is situated on the aortic side of the valve 2
- In cases of mitral valve endocarditis, giant vegetations can wedge into the aortic valve plane, causing obstruction to the left ventricular outflow tract 3
- The location and size of the vegetation can impact valvular function and increase the risk of embolization 3, 4
Valve Involvement
- Secondary involvement of the mitral valve is well documented in primary aortic valve endocarditis 4
- Mitral kissing vegetation can occur when large aortic vegetations prolapse into the left ventricular outflow tract and make contact with the ventricular aspect of the anterior mitral leaflet 4
- This can lead to secondary infection and worsen the prognosis of aortic valve endocarditis 4
Diagnosis and Management
- Echocardiography plays a key role in the assessment of vegetation morphology, risk of embolization, and impact on valvular function 3, 5
- Multidisciplinary care is imperative to the management of infective endocarditis, often requiring the expertise of cardiologists, cardiothoracic surgeons, infectious diseases specialists, radiologists, and neurologists 5