[Angiography in bypass grafts of the left anterior descending coronary artery with the left internal mammary artery. Apropos of 100 control examinations with a maximum follow-up of 6 years and 8 months].

Ninety three patients underwent 100 angiographic control studies of a left internal mammary artery bypass of the left anterior descending artery. The controls were carried out between 11 days and 6 years 8 months after surgery. Seven patients underwent two control studies. The patients were divided into three groups:--60 early control angiographic studies (before 2 years);--16 late control angiographic studies (between 2 and 5 years);--24 very late systematic control angiographic studies (after 5 years). The patency rate of the arterial grafts was 99%. From the anatomical point of view, the arterial walls of the internal mammary artery appeared smooth and regular except in one case. There was no cases of bypass graft disease. The ratio of the diameters of the internal mammary and left anterior descending arteries was greater than or equal to 1 in 93% of cases. The adaptation of the diameter of the internal mammary artery to that of the left anterior descending artery is an early phenomenon as shown by statistical and repeat control studies. The number of remaining collateral vessels does not appear to have an effect on the diameter of the internal mammary artery. Stenosis at the site of anastomosis was observed in 16% of cases. This seemed to be favoured when the angle subtended by the two vessels reached 90 degrees. The haemodynamic changes of the coronary circulation (competition of flow, competition of flow in the distal vessels, reflux in the internal mammary graft) were comparable to those observed in aorto-coronary saphenous vein bypass.