Valvular Abnormalities

Perforation of left-sided valves is a complication of endocarditis that may have important implications for clinical management. The echo definition of perforation is an interruption of leaflet continuity at a site removed from the commisures and color Doppler shows a high velocity eccentric jet traversing the defect at the leaflet (Figure 7.3) [21,22]. Valvular perforation should not be diagnosed when a regurgitant jet originates from the coaptation area and there is no evidence of interruption of leaflet continuity. Mitral and aortic regurgitation that results from valve perforation is usually eccentric.

Almost all mitral valve perforations and some aortic valve perforations occur within aneurysms arising from the infected valve. An aneurysm or diverticulum of the mitral valve is a saccular outpouching bulging into the left atrium during systole and collapsing during diastole (Figure 7.4) [22]. Frequently mitral valve aneurysms and perforations are associated with aortic valve vegetations and aortic regurgitation, likely a result of satellite vegetation on the mitral valve caused by the aortic regurgitant jet. Therefore, finding a mitral valve aneurysm and/or perforation in a patient with endocarditis should prompt a careful assessment of the aortic valve for vegetations and regurgitation.

The diagnosis of perforation is a predictor of the need for surgery and early mortality, because patients with perforation frequently have hemodynamically significant valvular regurgitation. Patients with valvular insufficiency due to perforation may be amenable to patch repair which is preferable in these patients [22]. Despite good response to medical therapy, patients with a valvular perforation should have clinical and imaging follow-up for progression of valvular regurgitation.

Endocarditis is the most common cause of mitral valve aneurysm and perforation. There

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Figure 7.3. A small aneurysm with perforation on the aortic non-coronary cusp on transesophageal echocardiography (A). Aortic regurgitation traversing the perforated aneurysm is shown by color flow imaging (B).

are very few non-endocarditis-related causes of mitral valve aneurysm such as osteogenesis imperfecta, Marfan's syndrome, Ehlers-Danlos, and pseudo xanthoma elasticum [23-25].

Transthoracic Echo

To image leaflet discontinuity directly by TTE requires high-quality images not usually obtained in most patients. The sensitivity of TTE for the diagnosis of valvular perforation is low and varies from 30% to 70% (Table 7.6) [21,22,26].

Transesophageal Echo

TEE is more sensitive for detecting valvular perforation than TTE (Table 7.6). In addition most

24 of 33

Figure 7.4. An aneurysm without perforation involving of the anterior mitral leaflet on both transthoracic (A) and transesophageal (B) echocardiography.

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perforations can be directly visualized rather than relying on the color flow jet traversing the valve leaflet. This direct visualization of a perforated leaflet increases diagnostic certainty (Figure 7.5). The size of perforations visualized on TEE agrees closely with pathologic examination and range from 2 to 7 mm [22]. The higher sensitivity of TEE for detecting vegetations is important in excluding aortic valvular IE as the cause for mitral valve perforation or aneurysm.

Table 7.6. Comparison of Transthoracic with Transesophageal Echocardiography in the Diagnosis of Valvular Perforation

Sample

Sensitivity

Sensitivity

Reference

Size

of TTE(%)

of TEE (%)

Cziner et al.,

1992 [21]

10

30

90

DeCastro et al.,

1997 [22]

20

70

100

Vilacosta et al.,

1999 [26]

13

38

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