Coronary collateral development in the rhesus monkey (Macaca mulatta).

The ability of the rhesus monkey to form coronary collaterals was tested in ten animals. Ameroid constrictors were implanted on the left circumflex coronary artery and allowed to remain for 12 weeks. One animal died of an acute myocardial infarction nine days after surgery; the remaining animals survived without clinical signs referable to myocardial ischemia. The hearts were excised at 12 weeks postsurgery for perfusion fixation and coronary vascular injection with barium-gelatin. All hearts exhibited infarction scars in the circumflex-perfused regions, with infarcts varying from a transmural scar to cases with a thin margin of surviving myocardium at the epicardial surface. Coronary collaterals were infrequent and small in size, and particularly evident in the atria. We conclude that the rhesus monkey is unable to develop sufficient coronary collateral blood flow to prevent myocardial infarction after gradual, total coronary occlusion with ameroid constrictors.