[Usefulness of the angiographic examination of the left internal mammary artery in patients candidates for coronary bypass surgery].

Background And Objective: The usefulness of preoperative angiographic evaluation of the internal mammary artery (IMA) is controversial. The aim of this study is to evaluate the problem by a basic cost-benefit analysis.

Methods: One hundred and twenty-one patients whose coronary findings (left main disease and/or severe stenosis of the left anterior descending artery) made use of the IMA as a bypass graft a consideration were studied. The IMA was cannulated by the same right Judkins catheter used in the coronarography; the specific catheter was only used if the cannulation was not successful with the right Judkins. We measured the time it took for a good angiography of the IMA to be obtained; the anatomy and the size for each IMA were studied and compared with the size of the left anterior descending artery.

Results: An optimal angiographic picture of the IMA was obtained in 119 cases (98.3%); a specific catheter was used only in 3 patients. The mean of the time employed was 170 seconds (8-900 s) and no complications were related to IMA cannulations. Angiography findings relevant to any planned surgery were demonstrated in 15 patients (12%): large proximal branches (10); occlusion stenosis or a caliber insufficient for IMA (3); and occlusion or proximal subclavian stenosis (2).

Conclusions: We have observed that the relation between the cost and the obtained information is adequate to warrant its performance, because angiographic findings relevant to planned surgery can be very important, even though they are fairly infrequent. Moreover, these findings can be achieved rapidly without additional cost.