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Aortic root abscess

Last revised by Assoc Prof Craig Hacking on 02 Jun 2021

An aortic root abscess is a serious complication of infective endocarditis and most commonly seen in patients who have had aortic root repair and/or aortic valve replacement.

Aortic root abscess occurs as a complication of infective endocarditis in 10-37% 9. Abscess formation in post-surgical patients (aortic root repair and/or aortic valve replacement) is most commonly encountered in the first 5 years following surgery, most of which occur in the first 2 years. 

Fever is almost universal in patients with aortic root abscess. Patients may also present with a new or changing murmur, valvular dehiscence, weight loss, poor appetite, systemic embolization, or features of congestive heart failure.

Early abscessation occurs within the first 2 months of surgery and is usually caused by perioperative contamination such as from skin, wound or prostheses. Staphylococcus epidermidis and S aureus the most frequent causative pathogens.

Late abscessation occurs greater than 2 months following surgery and resembles native valve endocarditis. Streptococci species are the most common causative pathogens.

In mechanical valves, infection starts at the sew line and extend around the valve. In bioprosthetic valves, infection resembles infective endocarditis of the native aortic valve where infection is limited to the cusps. The sewing cuff is rarely involved and periprosthetic abscesses are uncommon.

Abscesses tend to be saccular in shape, range from 1-3 cm in diameter. Depending on the sinus of origin, they may extend beneath the pulmonary trunk, right pulmonary artery, interventricular septum or mitral annulus.

Abscesses are heterogeneous hyperechoic lesions with perivalvular thickening. It may be difficult to differentiate a paravalvular abscess from a pseudoaneurysm 6, which is usually a defined collection with a visible direct connection with the aortic root or cardiac chambers that demonstrates color Doppler flow.

Abscesses appear as focal collections of hypodense material with peripheral contrast enhancement. Locules of gas may additionally be present in some cases. Phlegmon is represented by a thickened area around the aortic root 2. Pseudoaneurysms fill with contrast. Adjacent pericardial effusion may be present.

Hybrid imaging with Gallium-67 SPECT may complement workup 4

Patients can be managed with IV antibiotics alone but the prognosis is much greater when revision valve replacement and/or root repair is combined with IV antibiotics.

  • valve destruction and/or dehiscence
  • arrhythmias
  • fistulation into the mitral annulus, aorta or cardiac chambers

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Cases and figures

  • Case 1: periaortic abscess
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