Value of internal mammary artery bypass

Coronary artery bypass in 150 patients with angina has been accomplished with 225 IMA grafts and 85 saphenous vein grafts. There were 7 (4.7%) hospital deaths. Posterative catheterization in 85% of patients revealed that 9 (4.7%) IMA grafts and 11 (15%) vein graft had thrombosed. One-year catheterization in 32 patients (38 IMA grafts and 13 vein grafts) revealed no additional graft failures. The better patency of the IMA grafts appears to be related to their smaller size and therfore greater velocity of blood flow and freedom from intimal proliferation.