Free (aorta-coronary) internal mammary artery graft. Late results.

Free internal mammary artery grafts were placed in 156 patients (1971 to 1985). Preoperative clinical and angiographic variables were similar to those of other series of isolated coronary bypass grafts. Of 244 total internal mammary artery grafts, 166 were in the aorta-coronary position and were performed mainly because of unsuitable saphenous veins or to gain additional graft length. One patient (0.6%) died during hospitalization. Perioperative complications included respiratory dysfunction in 16 (10.3%), reoperation for bleeding in 13 (8.0%), stroke in four (2.6%), myocardial infarction in three (1.9%), and wound complications in two (1.3%). Morbidity occurred significantly more often in the 1971 to 1975 period. Subsequently, eight (7%) had reoperation (6 to 158 months; mean 99 months). After a 98 month mean follow-up, the 10 year actuarial survival rate (including all causes of death) was 73.3%. Of 40 free grafts restudied within 18 months of operation, 31 (77%) were patent. The higher rate of early closure is attributed to technical problems early in our experience, especially construction of the aortic anastomosis. However, 32 of 35 (91%) free grafts studied after more than 18 months (mean 94 months) were open. Fifty of 58 (86%) free internal mammary artery grafts placed to the anterior descending coronary artery, seven of nine (78%) to the circumflex, and six of eight (75.0%) to the right coronary artery were patent. Sequential catheterization showed that of 24 free grafts open at 9 months, 24 remained patent at 80 months; when six of these were restudied at 93 months (third catheterization) and two (fourth catheterization) at 125 months, all were patent. These late studies of free internal mammary artery grafts showed no evidence of graft atherosclerosis. Free internal mammary artery grafts, like in situ internal mammary artery grafts, appear to have relative immunity from atherosclerosis. These findings expand the versatility of internal mammary artery grafting and justify wider use of free internal mammary artery grafts.