[Clinical analysis of infective endocarditis with aneurysmal formation of the mitral or aortic valve].

Echocardiographic findings, clinical features, and pathophysiology of mitral and aortic valve aneurysms were evaluated in four patients with pathologically proven aneurysms of the mitral and/or aortic valves associated with infective endocarditis. These four were selected from 20 patients hospitalized in our institute from April 1990 to May 1995 because of infective endocarditis. All four patients had received repeated, inadequate antibiotic treatments at other medical institutions prior to admission, and underwent surgical repair because of acute hemodynamic exacerbation associated with aneurysmal perforation. Six aneurysms (three mitral and three aortic valve aneurysms) were detected before surgery, including two by transthoracic echocardiography and four by transesophageal echocardiography. The echocardiographic findings typical of aortic valve aneurysm were: ringed echo at the level of the aortic annulus in the short-axis view; turbulent flow within the ringed echo; and dome formation of the aortic valve that persisted throughout the cardiac cycle. All mitral valve aneurysms were true aneurysms without active inflammatory changes or significant destructive lesions, and were associated with severe infective aortic regurgitation. Histologic examination of the aortic valve in these patients showed active inflammation and extensive destruction, suggesting that these valves were the primary focus of infection. One patient had an aortic valve aneurysm without apparent mitral involvement, indicating that another mechanism had mediated aneurysmal formation. We conclude that: diagnosis of mitral or aortic valve aneurysms in patients with infective endocarditis has important therapeutic implications, and therefore, transesophageal echocardiographic examination should be done in such patients: there are three key echocardiographically diagnostic findings of aortic valve aneurysm as mentioned above; and several unknown factors may contribute to aneurysmal formation of the mitral or aortic valve in patients with infective endocarditis.