A combination of omental flap and growth factor therapy induces arteriogenesis and increases myocardial perfusion in chronic myocardial ischemia: Evolving concept of biologic coronary artery bypass grafting

Abstract

The purpose of this study was to evaluate the therapeutic efficacy of the combined growth factor therapy with an omental flap in a rabbit model of chronic myocardial ischemia. Chronic ischemia was created in rabbits by placing a constrictor on the left circumflex artery. Four weeks later the animals were divided into 3 groups: group FG, in which a gelatin hydrogel sheet incorporating 100 microg of basic fibroblast growth factor was placed over the left circumflex region followed by covering with the omental flap including the intact gastroepiploic artery; group F, in which only the basic fibroblast growth factor sheet was placed; and group N, in which no treatment was done. Cine magnetic resonance imaging analysis showed a greater percentage wall thickening in the left circumflex region in group FG than in other groups (group FG, 49.2% +/- 4.5%; group F, 41.2% +/- 3.8%; group N, 32.1% +/- 2.5%, P =.035, group FG vs group F). A colored microsphere assay showed higher perfusion in the left circumflex region in group FG than in group F. Perfusion in the left circumflex region was decreased after clamping the gastroepiploic artery pedicle in group FG (before clamping, 2.83 +/- 0.72 mL x min(-1) x g(-1); after clamping, 1.93 +/- 0.59 mL x min(-1) x g(-1); P < .01). In vivo angiography via gastroepiploic artery showed direct "to-and-fro" visible collaterals between the gastroepiploic and occluded left circumflex coronary arteries in group FG. The combined growth factor therapy with an omental flap induced arteriogenesis and provided additional perfusion via the gastroepiploic artery to ameliorate regional dysfunction in the chronically ischemic myocardium.