*5.2.3. Other complications*

Transthoracic echo was shown to have a combined sensitivity of 36–93% for native and

Harmonic sound waves are reflected back to the transducer at twice the frequency of the transmitted wave (fundamental frequency) and are subject to less near-field distortion and side lobe artifact. This results in a better signal-to-noise ratio with superior image resolution [47]. Specifically, there is an improvement in endocardial definition and visualization of the cardiac valves. However, the valve leaflet tissue itself may appear abnormally thickened when viewed

A number of studies have revisited the question of diagnostic accuracy of TTE for identification of mostly left-sided native valvular vegetations by comparing findings directly with TEE using modern era tissue harmonic imaging (hTTE). It remains unclear if modern era TTE imaging has resulted in improved detection of vegetations for left-sided vegetations, due to the wide

> **TEE multiplane#**

**Daniel et al. [67]** Sx 46 (NV + PV) No sens – – 28 – – 87

**Cicioni et al. [68]** Sx 29 (NV + PV) Yes sens – – 38 – – 93

TTE = transthoracic echocardiography; TEE = transesophageal echocardiography; NV = native valve; PV = prosthetic valve; sens = sensitivity; spec = specificity; Sx = surgery; path = pathology, either confirmed with surgery or at autopsy. \*modality against which sensitivity and specificity of TTE and/or TEE was compared against. #Multiplane TEE probe

Published data on diagnostic accuracy vary widely for abscess detection by TTE. Sensitivity has been reported at 28–81% with specificity 85–100% (**Table 3**). It is uncertain if harmonic imaging has positively impacted on the diagnostic accuracy, with some studies reporting no

**Sensitivity & Specificity**

Sx/path 30 (PV) Yes sens – – – – 90 –

**TTE TEE NV PV NV**

spec – – 99 – – 95

spec – – 85 – – –

spec – – – – – –

spec – – – – 100 –

spec – – – – – –

No sens – 64 81 – – –

Yes sens 33 40 36 75 88 80

**+PV** 

**NV PV NV +**

**PV** 

prosthetic valve vegetations and a specificity of 78–100% (**Table 1**).

*5.2.1.1. Harmonic tissue imaging*

72 Contemporary Challenges in Endocarditis

using harmonic imaging [59, 60].

variation in results reported (**Table 2**).

**standard\***

Sx/path 25 (NV)

Sx 64 (NV)

11 (PV)

43 (PV)

transducer utilised for imaging in some or all patients in a study.

**Table 3.** Diagnostic accuracy of TTE and TEE for detection of abscess.

**No. abscesses confirmed by gold standard\***

**Reference Gold**

**Aguado et al. [15]**

**Choussat et al.**

**San Román et al.**

*5.2.2. Abscess*

improvement [65, 68].

**[12]**

**[24]**

There are limited studies, generally with small patient cohorts, assessing the diagnostic accuracy of echocardiography for identifying complications other than vegetation and abscess.

Information regarding accuracy of TTE for identifying pseudoaneurysms is sparse, mostly because this pathological finding is often included in with the abscess group. According to one publication, only about one-half of intervalvular pseudoaneurysms were correctly diagnosed by TTE [21].

The sensitivity of TTE is approximately 50% [23] for detection of aorto-cavitary fistulas, but as high as 93% for detecting periannular dehiscence [68]. Detection rates for perforations with TTE range from 45 to 75% [68, 70, 71] and similar for valve aneurysms (38–75%) when compared with TEE as the gold standard [20, 72]. Not surprisingly valve aneurysms are most likely to be missed on TTE when small in size [21, 73].


IVDA = intravenous drug abuse; CDRIE = cardiac device-related infective endocarditis; TTE = transthoracic echocardiography; TEE = transesophageal echocardiography; ICE = intracardiac echocardiography; sens = sensitivity; spec = specificity; Sx = surgery; micro = microbiological diagnosis. \*modality against which sensitivity and specificity of echocardiography was compared against; #majority of patient cohort were IVDA

**Table 4.** Diagnostic accuracy of TTE and TEE for right-sided valvular and cardiac device-related vegetations.

#### *5.2.4. Subgroups of endocarditis*

Limited data have been published addressing the sensitivity of TTE in RSE [74]. For tricuspid valve IE, mostly in the IVDA cohort, sensitivity is high at 83–100% [75, 76], while detection rates in CDRIE are poor at 22–30% (**Table 4**). Transthoracic echo may be adequate for isolated native tricuspid valve IE, especially in IVDAs, unless image quality is suboptimal or if clinical suspicion remains despite negative TTE. Transesophageal echo should be utilized if there may be periannular infection, pulmonary, or left-sided valvular involvement or in the presence of an indwelling intravenous catheter [40].

The sensitivity of echocardiography for diagnosis of IE in CHD overall is estimated at 60–80%, but less sensitive if complex pathology is present [46]. In one study, approximately one-third of adult patients with CHD and a clinical diagnosis of IE had negative findings on TTE and/or TEE and up to 70% of echocardiograms were negative in palliated complex conditions [80].

In young children, TTE is often sufficient to diagnose IE due to superior acoustic windows compared to adults. Transthoracic echo in children with IE has a high rate of detection of vegetations (>90%) when compared with TEE as the gold standard [81].
