The porcine
ameroid model of chronic
myocardial ischemia has been widely used for the evaluation of coronary collateralization development. The impact of target vessel occlusion on the presence of
myocardial ischemia, and the relationship between morphological, functional, and hemodynamic measurements in the context of therapeutic angiogenesis studies, however, has not been studied thus far. The authors therefore performed a systematic analysis of 94 animals undergoing
ameroid constrictor placement around the left circumflex coronary artery (LCX) and, furthermore, a comprehensive evaluation including echocardiography and coronary angiography 26 +/- 1 (mean +/- SEM) days after
ameroid placement. Complete LCX occlusion was observed in 34/94 animals (36%) and identified those with
myocardial ischemia of the lateral wall, both at rest and under pharmacological stress. By applying a set of angiographic criteria (TIMI <or= 2 flow in LCX and/or collateral flow Rentrop class >or= 1), another 27/94 animals with
myocardial ischemia under conditions of pharmacological stress conditions could be identified. Interestingly, echocardiographic parameters of regional and global myocardial function were not correlated with myocardial blood flow or the degree of
ischemia. There was no relationship between the extent of coronary collateralization, as assessed by angiography, echocardiographic parameters, or myocardial blood flow. The authors therefore conclude that complete occlusion of the
ameroid instrumented coronary artery is not a prerequisite for successfully establishing the pathophysiology of
myocardial ischemia. Defined angiographic criteria are important in identifying ischemic animals, thus reducing total animal numbers. Angiographic assessment of the degree of coronary collateralization, however, is not associated with myocardial blood flow or function and should not be used as a primary outcome measure of therapeutic angiogenesis studies in this model.