[Mammary bypass dysfunction caused by proximal stenosis of the homolateral subclavian artery: treatment by percutaneous angioplasty. Apropos of a case].

Proper function of a coronary bypass using the internal mammary artery obviously depends upon the quality of the mammary artery used and of the distal coronary system, but also the absence of any significant stenosis of the first centimetres of the homolateral subclavian artery. The authors report the case of a patient in whom angina was destabilized by dysfunction of a bypass between the left internal mammary artery and the left anterior descending coronary artery. This mammary bypass dysfunction was related not to stenosis of the bypass but to stenosis of the proximal part of the left subclavian artery. Angioplasty of this stenosis led to disappearance of anterior myocardial circulatory impairment and of angina attacks.