CASE 10463 Published on 06.01.2013

A complication of endocarditis: aorto-left atrial fistula

Section

Cardiovascular

Case Type

Clinical Cases

Authors

Gabelloni M, Fiorini S, Lorenzoni G, Cervelli R, Faggioni L, Bartolozzi C.

Diagnostic and Interventional Radiology,
University of Pisa, Italy
Patient

80 years, male

Categories
Area of Interest Cardiac, Cardiovascular system ; Imaging Technique CT
Clinical History
An 80-year-old man with previous multiple interventions of prosthetic aortic valve replacement presented with fever, tachypnea, and elevated inflammatory markers. The last aortic valve intervention had been performed two months before.
Imaging Findings
Trans-oesophageal echocardiography (performed elsewhere) revealed a prosthesic abnormality suggesting the presence of endocarditis-related vegetations and aorto-left atrial fistula.
Contrast-enhanced multidetector CT (MDCT) demonstrated an abscess originating from the noncoronary sinus of Valsalva (measuring 7x12x15mm, APxLLxCC) bulging posteriorly towards the anterior wall of the left atrium (Fig. 1a-c). The abscess had a bilobar shape with an upper and a lower pole that appeared to be continuous to the left atrial wall and were thus compatible with aorta-atrial fistula (Fig. 2a-c).
Discussion
Endocarditis is an infection of the endocardial surface of the heart that can spread to large intrathoracic vessels and intracardiac structures. Its incidence is 3-10 per 100, 000 new individuals per year. Microorganisms can usually be demonstrated on the infected tissues, and among them, streptococci and staphylococci are responsive for the majority of cases with identified microbiology.
Transthoracic and trans-oesophageal echocardiography (TTE/TEE) allow to make a correct diagnosis of endocarditis by accurately depicting valve vegetations and the disruption of valve leaflets, as well as to quantify the residual valvular function by means of colour Doppler. In particular, TEE sensitivity is very high and can reach 90-100% [1].
MDCT represents the mainly diagnostic imaging modality for patients with suspected endocarditis-related complications, as it can reveal abnormalities in different organ systems [2].
Congestive heart failure is the most important complication of endocarditis. Systemic embolization occurs in 22% to 50% of cases; emboli may involve major arteries, mostly affecting the central nervous system, but also other organs. Splenic abscess is a rare complication of endocarditis, due to direct seeding of spleen by an embolus or bacterial seeding of a bland infarction. Periannular abscesses are a relatively common complication (42% to 85% of cases during surgery or at autopsy, respectively), associated with a higher morbidity and mortality [3]. A rare evolution of abscess formation is the development of aorto-cavitary fistula. Fistulae occur with a prevalence of 1.7%, rising to 5.8% in patients with prosthetic valve endocarditis. Fistulae occur only in aortic valve endocarditis, usually in association with identifiable peri-valvular abscess formation, and with equal distribution among all three coronary sinuses and all four cardiac chambers. Surgical correction is performed in 87% of patients, largely in conjunction with aortic valve replacement, and in hospital post-operative mortality is as high as 42% [4].
Differential Diagnosis List
Periprosthetic abscess with aorto-left atrial fistula
Acute pericarditis
Sinus of Valsalva aneurysm
Diverticulum of aorta
Final Diagnosis
Periprosthetic abscess with aorto-left atrial fistula
Case information
URL: https://www.eurorad.org/case/10463
DOI: 10.1594/EURORAD/CASE.10463
ISSN: 1563-4086