Morphometric analysis of the right gastroepiploic artery and the internal mammary artery

The internal mammary artery (IMA) and the right gastroepiploic artery (RGEA) are frequently used as conduits for coronary artery bypass grafting. Morphometric measurements and histologic characteristics of the RGEA and the IMA were studied in 25 patients undergoing coronary artery bypass grafting. External radius was found to be more in the IMA (range, 18 to 56 μm; mean, 39.56 μm) in comparison with the RGEA (range, 24 to 51 μm; mean, 32.52 μm; p < 0.01). There was no significant difference between the vessels in intimal thickness (IMA: 0.0 to 0.25 μm; mean, 0.05 μm; RGEA: 0.0 to 0.28 μm; mean 0.09 μm), internal radius (IMA: 5 to 47 μm; mean, 28.40 μm; RGEA: 16 to 42 μm; mean, 23.56 μm), area of media (IMA: 1,690 to 3,476 μm 2; mean, 2,777.52 μm 2; RGEA: 1,659 to 3,600; mean, 3,012.44 μm 2), intimal thickening index (IMA: 0.0 to 0.02; mean, 0.01; RGEA: 0.0 to 0.13; mean, 0.01), and medial index (IMA: 0.14 to 0.60; mean, 0.36; RGEA: 0.18 to 0.63; mean, 0.39). Histologic examination of the RGEA showed more defects in continuity of internal elastic lamina and rich smooth muscle cells in the media. There was no difference in the morphometric measurements of the IMA and the RGEA except external radius, which was greater for the IMA. The histologic differences found in the RGEA may indicate an increased propensity for atherosclerosis of the RGEA as compared with the IMA. Some concern regarding the long-term patency of the RGEA in myocardial revascularization is warranted.