RESUMEN
A 51-year-old man developed a high fever with congestive heart failure after treatment for his dental caries and was admitted to our hospital. Transesophageal echocardiogram showed severe aortic regurgitation with a bicuspid aortic valve where vegetation and perforation was identified on its leaflets. Infective endocarditis caused by <i>Streptococcus constellatus</i> was diagnosed by blood culture. A computed tomography scan of the chest showed enlargement of his ascending aorta with a maximum diameter of 5.0cm. After treatment with antibiotics and diuretics for 60 days, he underwent surgical treatment for his aortic valve and ascending aorta. After excising the diseased aortic leaflets with vegetation, a mechanical prosthetic valve (Carbomedicus 23mm) was implanted. His ascending aorta was also replaced separately with a woven Dacron tube graft. There was an anomalous origin of the right coronary artery which was detached from the ascending aortic wall as a button and was implanted on the tube graft. Histologically the aortic wall showed disappearance of elastic fibers with myxomatous degeneration in the media. Immunohistochemical staining also revealed that matrix metalloproteinase-2 (MMP-2) was strongly expressed in the aortic media. The postoperative course was uneventful and he was discharged on the 37th postoperative day.