Post-radiotherapeutic left main coronary ostial stenosis: clinical and histological study

Pericardial abnormalities remain the most common manifestationof radiation-induced cardiac disease, but coronary artery lesionsare not rare. In this report we describe a left coronary ostialstenosis which appeared five years after mediastinal irradiationfor breast carcinoma in a 50-year-old woman. The patient underwentcoronary angiography. A pressure drop was observed as the leftcatheter tip engaged the left coronary ostium; so, only nonselectivecoronary opacifications were performed showing an isolated,marked narrowing of the left coronary ostia. During surgery,a circumferential aortotomy allowed the examination of the leftcoronary ostium which appeared severely stenosed. The coronarytree was otherwise normal. A termino-terminal saphenous veingraft was anastomosed on the left stem and its proximal partwas implanted on the ascending aorta. The coronary ostium andthe proximal part of the left main stem were excised and themacroscopic examination of the proximal part of the left coronaryartery confirmed the diagnosis of severe ostial stenosis. Microscopicexamination of the coronary ostium showed a severe intimal thickeningwithout any evident lesion of the media. This intimal thickeningconsisted of fibrous tissue without extracellular lipid deposit.Microscopic examination of the aorta near the coronary ostiumalso demonstrated an intimal thickening without any lesion ofthe media. Coronary ostial stenosis appears to be a rare lesion;its incidence has varied between 0·13 and 2·7%in angiographic studies and there is co-existing disease inmultiple coronary vessels in the majority of cases. This coronarylesion in a middle-aged woman after a mediastinal irradiation,its histologic aspect (pure intimal fibrous thickening), andthe secondary appearance of complete atrio-ventricular block,fits the pattern previously ascribed to radiotherapy. Only twoother cases of coronary ostial lesion almost certainly secondaryto mediastinal irradiation have been reported.