Risk factors for stroke after coronary artery bypass grafting (CABG) were assessed. We retrospectively investigated 681 consecutive patients who underwent isolated, first-time CABG at our institute between 1987 and 1998. Ninety-eight patients (14%) had a history of preoperative stroke. They tended to be older and with a higher incidence of peripheral vascular disease (PVD) than those without preoperative stroke. In spite of several techniques for prevention of postoperative stroke, such as the aortic non-touch technique, 14 patients (2.0%) suffered postoperative stroke. Postoperative stroke was diagnosed soon after surgery in 7 patients (50%), and the causes of stroke in these patients seemed to be intraoperative manipulation of the ascending aorta in 5, and hypoperfusion during cardiopulmonary bypass in two. Stroke in the remaining 7 patients occurred after normal awakening from anesthesia, and the cause was unknown. We then compared the patients with postoperative stroke (n=14) to those without postoperative stroke (n=667). Statistical analysis demonstrated no significant difference between the two groups in variables such as history of preoperative stroke, duration of cardiopulmonary bypass, and prevalence of PVD. Four (29%) of the patients with postoperative stroke died, due mainly to aspiration pneumonia. The morbidity and mortality of the patients who suffered postoperative stroke were very high.

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 Streptococcus constellatus 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.