Indirect myocardial revascularization--an experimental study in thedog

Abstract

It has been shown in previous studies that grafting a free skeletalmuscle flap onto the heart of the dog produces myocardialrevascularization. In order to evaluate the functional aspect of theseneovessels, an Ameroid constrictor was implanted into the LADs (leftanterior descending coronary artery) of five dogs. At the same time, thefree muscle flap was grafted onto the anterior wall of the heart. Thearterial anastomosis was achieved with the internal mammary artery. Venousflow was drained into the right atrium. About 12 months later, the regionalmyocardial blood flow was evaluated adopting the radioactive microspheretechnique. This was carried out with the LAD occluded by the Ameroidconstrictor and the circumflex artery (CX) open (control conditions). Thenthe CX was occluded in order to exclude collateral blood flow. Afterwardsanother occlusion of the CX was performed ("preconditioning") to producemaximal opening of the anatomical collaterals. It was found that regionalmyocardial blood flow was unchanged in the antero-lateral parts of thehearts despite complete occlusion of the coronaries supplying this area. Inthe parts supplied by the CX, though, flow was minimal. "Preconditioning"positively influenced the perfusion of this region only in the epicardialparts. Histologically large sinusoid-like blood conductors connected thegraft and the heart. Thus, grafting a free skeletal muscle flap onto theheart in the dog produces functional myocardial revascularization in thedog.