[Bilateral coronary ostial stenosis after aortic valve replacement with freestyle stentless bioprosthesis: a case report].

An 80-year-old woman underwent aortic valve replacement with Freestyle stentless prosthetic valve for the stenosis. Four months later, she was admitted with myocardial ischemia. Coronary angiography revealed severe stenosis in the ostium of both right and left coronary arteries. Coronary artery bypass grafting was performed. One year later, percutaneous coronary intervention was carried out for the bilateral coronary arteries because of unstable angina. Intravascular ultrasonography demonstrated localized, membranous, homogeneous, and severe stenoses in the ostium of the right and left coronary arteries. Histological examination of a specimen taken by directional coronary atherectomy showed intimal hypertrophy, mucinous degeneration, and hyaline degeneration without reactive change. There were no findings of atherosclerosis. These clinical, angiographical histological and intravascular ultrasonography findings suggest that the immunological reaction to the heterograft was the mechanism of the bilateral ostial coronary arteries stenoses in the present case. The possibility of immunological reaction after aortic valve replacement with heterograft should be considered. There have been no report on intravascular echocardiographic and histological findings.