ECHOCARDIOGRAPHY IN THE DIAGNOSIS OF INFE CTIVE ENDOCARDITIS - VALUE AND LIMITATIONS

This cooperative study recensed 148 patients who had infective endocar ditis (IE) with anatomopathological correlations. The infection was on native valves in 89 cases and prosthetic valves in 59 cases. Transoes ophageal echocardiography diagnosed vegetations on native valves with a sensitivity, specificity, positive predictive and negative predictiv e values of 89 %, 87 %, 88 % and 90 % respectively, whereas for transt horacic echocardiography the results were 68 %, 83 %, 81 % and 72 % re spectively. With respect to prosthetic valve vegetations, transoesopha geal echocardiography had a sensitivity, specificity, positive predict ive and negative predictive values of 67 %, 84 %, 48 % and 92 % respec tively compared with 56 %, 84 %, 44 % and 83 % respectively for transt horacic echocardiography. These results underline the difficulties in differentiating degeneration and endocarditis of bioprostheses. Transo esophageal echocardiography diagnosed aneurysm formation and valvular perforation with a sensitivity, specificity, positive and negative pre dictive values of 61 %, 93 %, 91 % and 72 % respectively compared with 35 %, 96 %, 98 % and 58 % respectively for transthoracic echocardiogr aphy. The false negative results of transoesophageal echocardiography were usually observed in lesions of the posterior leaflet or commissur es. In this series, the 6 aortic cusp perforations were undiagnosed by both transthoracic and transoesophageal echocardiography. With respec t to aortic ring abscess, the sensitivity, specificity, positive and n egative predictive values of transoesophageal echocardiography were 89 %, 100 %, 100 % and 93 % respectively, compared with 27 %, 100 %, 100 % and 62 % for transthoracic echocardiogphy. The false negative resul ts of transoesophageal echocardiography were observed in cases of ante rior abscesses or of calcific aortic valves. These results demonstrate the superiority of transoesophageal over transthoracic echocardiograp hy in the diagnosis of infective endocarditis and its complications. H owever, the limitations of the method should be recognised in the situ ations described.