Optimising the use of transoesophageal echocardiography in diagnosing suspected infective endocarditis

Abstract

Objectives We evaluated the clinical indication and incremental diagnostic yield gained by transoesophageal echocardiography (TOE) performed after transthoracic echocardiography (TTE) in patients with suspected infective endocarditis (IE).

Methods and results We retrospectively analysed 60 pairs of TOE and TTE exams for suspected IE, performed between July 2011 and July 2013 in our district general hospital. The TOE results were classifi ed as ‘positive’ or ‘negative’ based on the Duke criteria, while TTEs were classifi ed as ‘no vegetation’, ‘vegetation’, ‘suspected vegetation’ and ‘cannot exclude vegetation’ according to the fi nal reports. Pre-existent valve disease and Greaves clinical criteria (prosthetic valve, IVDU, positive blood cultures, embolic phenomena and central lines) were also recorded.

Among 22/60 (36%) patients, there was no additional diagnostic yield from further TOE after TTE. Of these 22 patients, 6 had negative Greaves criteria while 16 were Greaves positive but had no evidence of IE on TTE in the presence of good image quality. TOE had a higher diagnostic yield in the remaining 38 patients especially in the presence of prosthetic valves, calcifi ed aortic valves, myxomatous/prolapsing mitral valves and poor TTE image quality.

Conclusions TOE is not required in patients with low clinical suspicion of IE, when TTE images are of good quality, as there is no additional diagnostic yield.

TOE has a higher diagnostic yield and remains a useful tool in patients with intermediate to high suspicion of IE in the presence of poor TTE image quality, calcifi ed aortic valve, myxomatous mitral valve and prosthetic valves.

Key Words:

• Infective endocarditis
• transthoracic echocardiogram
• transoesophageal echocardiogram