Development of biologic coronary artery bypass grafting in a rabbit model: revival of a classic concept with modern biotechnology

Abstract

Objective We have developed a technique for biologic coronary artery bypass grafting, which is a revival of a classic concept with modern biotechnology. Methods Acute myocardial infarction was created by ligating the major branch of the circumflex artery in rabbits. Animals were divided into four groups: a nontreated group (group N), a group in which omentum was used to wrap the infarcted area (group G), a group in which a gelatin hydrogel sheet incorporating 100 μg basic fibroblast growth factor was placed over the infarcted area (group F), and a group in which the infarcted area was similarly treated with basic fibroblast growth factor followed by omental wrapping (group FG). Cardiac function was subsequently assessed by echocardiography. Postmortem angiography through the gastroepiploic artery was done in groups G and FG. Infarct size and arteriolar density were evaluated. Results Group FG showed a better fractional area change than did the other groups (group N P < .001, group G P = .002, group F P < .001). Angiography revealed that communication from the gastroepiploic artery to the coronary artery was created through a rich bed of neovascularization in all 7 animals of group FG, whereas poor collaterals were recognized in only 2 of 7 animals in group G. Infarct size was reduced to a greater extent in group FG than in groups F, G, and N (10% ± 3%, 16% ± 5%, 19% ± 7%, 23% ± 2%, respectively, group F P = .04, groups G and N P < .01). The number of arterioles 20 to 100 μm in diameter was increased to a greater extent in group FG than in groups F, G, and N (23 ± 5 arterioles/mm 2, 14 ± 3 arterioles/mm 2, 10 ± 1 arterioles/mm 2, 4 ± 2 arterioles/mm 2, respectively), with the differences being significant. Conclusions These results show that bypass from the gastroepiploic artery to coronary arteries can be achieved without surgical anastomosis through slow release of basic fibroblast growth factor in this rabbit acute myocardial infarction model. This new revascularization concept, biologic coronary artery bypass grafting, could be applicable for revascularizing many tiny coronary vessels in patients who are difficult to treat with conventional surgery or catheter intervention.