CARDIAC AND EXTRACARDIAC ABSCESSES IN INF ECTIVE ENDOCARDITIS

Cardiac abscesses are observed in 20 to 30 % of cases of infective end ocarditis and in at least 60 % of prosthetic valve endocarditis. The a ortic valve ring is more frequently affected than the mitral valve rin g. A cavity contiguous with a cardiac chamber forming a pseudo-aneuris m or a closed purulent collection, the abscess may extend to the neigh bouring cardiac structures or to the ascending aorta. This extension m ay cause conduction defects, abnormal communications between the cardi ac chambers, pericardial disease and, exceptionally, myocardial ischae mia, complications which are clinical signs of abscess formation in pa tients with infective endocarditis. The presence of a cardiac abscess is a poor prognostic factor in infective endocarditis. The diagnosis m ust be made at an early stage when surgical treatment is optimal. The most valuable investigation is transoesophageal echocardiography with a sensitivity of over 80 % and a specificity of about 95 %. This inves tigation has become practically routine in all patients with endocardi tis in order to diagnose abscesses at an early stage, especially in ca ses of aortic or prosthetic valve endocarditis. Information about the site, size and extension of the abscess may be obtained and existing o r potential complications may be envisaged with a view to surgery. Oth er imaging diagnostic techniques, such as angiography, CT scanning and nuclear magnetic resonance imaging have a number of disadvantages and are not more sensitive than transoesophageal echocardiography. Surgic al techniques depend on the site and extension of the abscess. They ar e sutured or closed with dacron or pericardial patches after having be en cleaned and filled with formolated resorcin glue. The valvular pros thesis is inserted either in anatomical position or in a sub or suprac oronary dacron tube necessitated by the perivalvular extension of the infectious lesions. These complex procedures may require associated co ronary reimplantation or revascularisation when the coronary ostia are affected. The highest operative mortality is observed in prosthetic v alve endocarditis with abscess and extra-annular prosthetic implants. The risk of secondary valvular dehiscence, often recurrent, is much hi gher when there is an abscess at operation. Extracardiac abscesses in cases of infective endocarditis are mainly observed in the cerebral an d/or splenic territories. They may become the main problem, especially cerebral abscesses, but they rarely require surgery.