Occur in 10 per cent to 40 per cent of all native-valve IE, and complicates aortic IE more commonly than mitral or tricuspid IE. Periannular infection is of even greater concern with prosthetic-valve IE, occurring in 56 per cent to 100 per cent of patients. Perivalvular abscesses are particularly common with prosthetic valves because the annulus, rather than the leaflet, is the usual primary site of infection. In native aortic-valve IE, this generally occurs through the weakest portion of the annulus, which is near the membranous septum and atrioventricular node.  Clinical parameters for the diagnosis of perivalvular extension in a patient with IE who is taking adequate antibiotics are:

• Persistent bacteremia or fever
• Recurrent emboli
• Heart block
• CHF
• New pathological murmur

Only aortic-valve involvement and recent IVDA have been prospectively identified as independent risk factors for perivalvular abscess. On ECG, new atrioventricular block has an 88 per cent  positive predictive value for abscess formation but has a low sensitivity (45 per cent).

The sensitivity of TTE to detect perivalvular abscess is low (18 per cent to 63 per cent in prospective and retrospective studies, respectively). TEE improves the sensitivity for defining periannular extension of IE (76 per cent to 100 per cent) while retaining excellent specificity (95 per cent) and positive and negative predictive values (87 per cent and 89 per cent, respectively). When it is combined with spectral and color Doppler techniques, TEE can demonstrate the distinctive flow patterns of fistulae and pseudoaneurysms and can rule out communications from unruptured abscess cavities. Surgery for patients with perivalvular extension of IE directed toward eradication of the infection as well correction of hemodynamic abnormalities. Drainage of abscess cavities, excision of necrotic tissue, and closure of fistulous tracts often accompanies valve-replacement surgery. Human aortic homografts, when available, can be used to replace the damaged aortic valve as well as to reconstruct the damaged aorta. Those pts who do not have heart block, echocardiographic evidence of progression of abscess during therapy, valvular dehiscence, or insufficiency can be managed with out surgical intervention. Such patients should be monitored closely with serial TEE, and TEE should be repeated intervals of 2, 4, and 8 weeks after completion of antimicrobial therapy.