Aneurysmal pouch on left coronary cusp accompanied by bacterial endocarditis.

A 58-year-old male was admitted to our hospital with a preliminary diagnosis of bacterial endocarditis. After admission, echocardiography indicated the presence of vegetation-like tissues on both the left coronary cusp and the anterior mitral leaflet, although retrograde aortography two months earlier hadn't indicated an abnormal finding on the aortic cusp. The vegetation-like tissues had gradually enlarged despite the administration of antibiotics at another hospital, and aortic and mitral regurgitation had become severe. We decided to perform replacements of the aortic and mitral valves on the day of admission. During the operation, the aortic valve was found not to have vegetation, but an aneurysmal pouch on the left coronary cusp. It was supposed that either bacterial endocarditis or catheter injury had made a part of the aortic cusp weak and intolerant of diastolic pressure gradient, and as a result, the weakened part of the cusp progressively dilated into the left ventricle forming an aneurysmal pouch. To our knowledge, there have been only two previous reports of an aneurysmal pouch on the aortic cusp documented in the literature.