A new method for assessment of collateral development after acute myocardial infarction

Objeaitrs. The purpose of this study was to test the hypothesis that the diameter of the recipient coronary artery of the well developed collateral circulation in patients with acute myocardial infarction increases because of the augmented intravascular pressure caused by subsequent collateral development. Background. It is well known that collateral circulation develops after acute myocardial infarction. However, some patients have a well developed collateral circulation at the onset of infarction, which may limit the angiographic evaluation of further development of collateral circulation. Methods. We measured the diameter of the donor and recipient arteries of the collateral circulation by means of a computerassisted analysis system in seven patients with acute myocardial infarction who had a totally occluded infarct-related coronary artery during the acute and chronic stages of infarction. All coronary angiograms were obtained after the administration of sublingual nitroglycerin. The measurement was repeated immediately after (within 6 h) and late after (42 ± 11 days) the onset of acute myocardial infarction. Results. The diameter of the donor artery remained unchanged (1.32 ± 0.98 vs. 1.42 ± 1.12 mm). In contrast, the diameter of the recipient artery increased from 1.25 ± 0.63 to 1.55 ± 0.61 mm (p < 0.01). These changes in coronary artery diameter were associated with an improvement in regional myocardial wall motion at rest in infarct areas (6.7 ± 7.0% vs. 13.6 ± 10.7%, p < 0.05). Conclusions. These findings indicate that serial measurement of coronary artery diameter is useful for the evaluation of collateral development after acute myocardial infarction.