[Diffuse narrowing of the internal mammary artery graft--the thinning phenomenon]

Diffuse narrowing of the internal mammary artery graft (IMAG), the thinning phenomenon, was found in 8 (6.7%) out of 120 IMAGs underwent postoperative angiography. There were 6 males and 2 females, and mean age was 55.3 ranged from 37 to 70 year-old. There was no significant correlation with hyperlipidemia, diabetes mellitus or hypertension. Grafted coronary arteries were 6 anterior descending, one diagonal and one circumflex arteries. Diameter of them was 1.5 mm in one and 2 mm in 7. severity of stenosis of proximal coronary artery was 100% in one, 90-99% in one and less than 90% in 6. Undivided sizable costal or pericardial branches were found in 4 patients. All eight patients were alive without angina, although mild positive stress EKG changes were noted in two patients. In conclusion, a high resistance state such as a good competitive native coronary flow was thought to be the most important factor for the diffuse narrowing of IMAG, and close follow up should be needed because its outcome is still unknown.