Computed Tomography in Prosthetic Aortic Graft Infections

Abstract

Prosthetic aortic grafts infection is associated with consider-able morbidity and mortality. Staphylococcus species are themost commonly implicated causative organisms. Computedtomography (CT) is the imaging modality of choice in theinvestigation of patients with suspected prosthetic aorticgraft infection, particularly in the assessment of abscessand pseudo-aneurysms associated with aortic graft infec-tions.WedescribetwocasesinwhichCTprovidesincremen-tal information about the complications associated withprosthetic aortic graft infection which is essential in guidingtreatment and management.Case 1: 45 year-old man with previous Bentall’s graft with25 mm St Jude valve conduit for bicuspid aortic valve anddilated aortic root presented with night sweats, weight loss,and rash. Transthoracic echocardiogram (Fig. 1A, video I)demonstrated a large pseudo-aneurysm anterior to the Ben-tall’s with free moving echogenic mass within likely consis-tent with vegetations. CT thoracic aorta (Fig. 1B-1D) showeda large complex pseudo-aneurysm anterior to the aortic rootand the main pulmonary artery with fistula origin at theright coronary artery anastomosis. He subsequently under-went redo Bentall’s procedure with 23 mm ATS bileafletmechanical valve and 30 mm Gelweave valsalva graft. Sur-gery confirmed a large pseudo-aneurysm arising from theaortic root with vegetations in the cavity. Propionibacteriumacnes was isolated and he was treated with six weeks ofintravenous benzyl penicillin followed by oral penicillinfor three months.Case 2: 19 year-old man with end-stage renal failure pre-sented with an aortic root abscess (Fig. 2A) secondary toMethicillin-resistant Staphylococcus aureus bacteraemia withthe presumed infection likely arising from right internaljugular tunnelled line for haemodialysis. He underwent anurgent homograft aortic root replacement in view of severeaorticincompetence(Fig.2B)and completeheartblock.Post-operative echocardiogram (Fig. 2C & 2D, videos II & III)showedalargeparavalvularechofreespaceposteromediallyand another anterolaterally consistent with pseudo-aneurysm. CT thoracic aorta (2E & 2F) demonstrated twopseudo-aneurysms arising from the left ventricular outflowtract. Redo aortic root replacement was performed but com-plicated by significant bleeding from the root despite multi-ple suturing, topical measures and packing, and eventuallyhe died.Keywords Computer tomography Echocardiogram Prosthetic aortic graft infections