Impact of harmonic imaging on transthoracic echocardiographic identification of infective endocarditis and its complications

Abstract

Objective: To evaluate the comparative diagnostic value of harmonic imaging (HI) in the assessment of patients with suspected infective endocarditis (IE). Setting: Tertiary referral centre. Design: 139 consecutive patients were evaluated with three imaging modalities: transthoracic echocardiography with fundamental imaging (FI); HI; and transoesophageal echocardiography (TOE). Image quality was assessed for each modality by semiquantitative scoring (0, poor, to 3, excellent). Presence, dimension, and characteristics of vegetations were assessed separately for each imaging modality, as well as presence of abscesses. Results: 35 patients had definite IE. TOE was positive in 33 patients, HI in 28, and FI in 12 (p , 0.001 for FI v HI and v TOE). Mean image quality was 1.4 (0.7) for FI, 2.1 (0.6) for HI (p , 0.01 v FI), and 2.6 (0.4) for TOE (p , 0.001 v HI). The association between FI and TOE findings was W = 0.35 (x 2 = 17.57, p = 0.0014) and between HI and TOE it was W = 0.95 (x 2 = 125.72, p , 0.0001; p , 0.0001 v FI). The global echo score of vegetations was 7.1 (3.3) with FI, 8.5 (3.4) with HI, and 11.3 (3.9) with TOE (p , 0.001 v HI). Compared with TOE, FI identified only one of seven abscesses (sensitivity 14%) and HI identified two of seven abscesses (sensitivity 28%). Conclusions: HI provides an accurate assessment of suspected IE. TOE achieves superior definition of IE related abnormalities. D espite advances in diagnosis and treatment, infective endocarditis (IE) still has high morbidity and mortality often due to delayed diagnosis.

Swedish guidelines for diagnosis and treatment of infective endocarditis recommend overuse of transoesophageal echocardiography

“…The studies were scarcely replicated when new imaging techniques emerged. There are to our knowledge only 3 studies that have evaluated the diagnostic capacity for TTE and TEE of IE in native valves, with the imaging techniques currently used [7,8,21]. There are to our knowledge no studies that have exclusively investigated prosthetic valves.…”

“…There are to our knowledge no studies that have exclusively investigated prosthetic valves. The message from 2 of the studies concerning native valves is very simple Á if the image quality is good with TTE, then there is very little difference in the diagnostic capacity between TTE and TEE [8,21], whereas 1 study came to a different conclusion [7]. Even in a highrisk group such as patients with Staphylococcus aureus bacteraemia, TEE only found vegetation in 14% of the patients, which was not detected by TTE [9].…”

Echocardiography in Fever Investigation in Patient with Long Term Central Venous Catheter

“…Nos pacientes considerados de baixo risco para endocardite infecciosa, um exame transtorácico de boa qualidade é suficiente para descartar o diagnóstico. Por outro lado, naqueles em que a suspeita clínica persiste, mesmo com exame transtorácico negativo, deve ser realizado o estudo transesofágico 7,8 . O ETE é um método seguro, com taxas de complicações muito baixas, possui maior acurácia diagnóstica em relação ao ETT, com excelente sensibilidade para detecção de vegetações (82% a 94%) e especificidade próxima aos 100% 9 .…”

Modern epidemiology, prophylaxis, and diagnosis and therapy for infective endocarditis

“…Institutions with a high prevalence of patients with IDU, particularly with heroin, may see many patients with IE restricted to the tricuspid valve. These patients tend to do well with medical therapy, and their vegetations are often well seen on transthoracic views, particularly with modern echocardiography equipment and the use of harmonic frequencies [23]. In those patients, initial TTE may also be appropriate, followed by TEE if the patient's course is complicated (eg, by unexplained on-going sepsis, heart failure, or changing cardiac examination).…”