Echocardiography in endocarditis

Echo in Endocarditis
Background:

Valvular vegetations were first described in 1973 using M mode echocardiography by Dillon and colleagues. Currently, the Duke criteria combine echocardiographic findings with clinical and microbiological data. The diagnosis of endocarditis requires the presence of two major criteria, or one major and three minor criteria.

Three echocardiographic findings are considered major criteria for the diagnosis of endocarditis:

• oscillating intracardiac mass on valve or supporting structures, in the path of regurgitant jets, or on implanted material in the absence of an alternative anatomic explanation, or

• abscess, or

• new partial dehiscence of prosthetic valve

Detection of Vegetation by echocardiography:

The sensitivity of transthoracic echocardiography (TTE) is generally superior to transesophageal echocardiography (TEE). However, vegetation size affects the specific estimates of sensitivity and specificity. For example, using TTE, only 25% of vegetations < 5 mm and 70% of those between 6 – 10 mm were identified by TTE in one series (reference).

Native Valve Endocarditis:

Rough estimates of sensitivity and specificity in the detection of native valve endocarditis are shown below.

Sensitivity:

-	The sensitivity of TTE ranges between 40 – 63% (reference)

-	The sensitivity of TEE ranges between 90 – 100% (reference)

Specificity:

-	varies according the population studied.

-	estimated at > 90 % (reference Jacob et al) for both TTE and TEE.

Prosthetic Valve Endocarditis:

-	accounts for 7 to 25% of all endocarditis (reference)

-	TEE is superior to TTE in diagnosing prosthetic valve endocarditis (sensitivities were 82% and 36% respectively). (reference)

Use of echocardiography to predict complications of endocarditis:

1.	embolization -

2.	valve perforation -

3.	perivalvular abcess -

Impact of echocardiography on diagnosis and management of infective endocarditis:

Cost-effectiveness analysis:

Negative predictive value of TEE:

Diagnostic algorithm:

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References: