Flow Capacity of Gastroepiploic Artery Versus Vein Grafts for Intermediate Coronary Artery Stenosis

Native flow competition is a significant factor affecting bypass graft patency. The objective of this study was to compare the effect of competitive flow on conduit flow dynamics in the gastroepiploic artery (GEA) and the saphenous vein graft (SVG). In 51 patents, 23 GEAs (in-situ grafts) and 28 SVGs (aortocoronary grafts) were examined using a Doppler-tipped guidewire during coronary angiography after coronary artery bypass. Graft flow volume at rest and maximum graft flow volume during hyperemia were calculated from graft diameter and average peak velocity at rest and maximum average peak velocity induced by papaverine hydrochloride injection. Grafts were classified according to the grade of native coronary artery stenosis; group S (14 GEAs and 16 SVGs) displayed over 75% stenosis and group M (9 GEAs and 12 SVGs) exhibited over 50% up to 75% stenosis. In group S, no difference in flow volume was apparent between the GEA and the SVG at rest (36± 17 vs 42 ± 16) and during hyperemia (78 ± 30 vs 88 ± 28). In group M, flow volume of the GEA was significantly lower than that of the SVG at rest (17 ± 11 vs 38 ± 12; p = 0.029) and during hyperemia (32 ± 19 vs 94 ± 46; p = 0.001). These data suggest that in intermediate coronary stenosis, GEA flow is compromised by native flow competition, whereas the SVG flow dynamics is maintained. However, the GEA can provide comparable flow capacity to the SVG and will achieve good surgical results when target coronary artery selection is appropriate.