[Coronary artery bypass grafting for a patient with hypothyroidism--a case report].

A 59-year-old female who had been treated for hypothyroidism was admitted with angina pectoris and underwent aorto-coronary bypass grafting. On closing of the sternum, there was unexpected bleeding from the suture line between the vein graft and the ascending aorta. Histological examination of the aortic wall revealed sparsity and disruption of elastic fibers and deposition of mucopolysaccharide without any findings of atheromatous change. It is concluded that hypothyroidism can cause histological change of the aortic wall and that surgical procedures involving the aortic wall in patient with hypothyroidism should be avoided if possible.