Coronary collateral development after acute myocardial infarction

In 31 patients without a history of preinfarction angina, coronary collateral circulation to the completely obstructed coronary artery was evaluated by coronary angiography during a convalescent period of their first myocardial infarction. Collateral visualization (collateral index) was found to be significantly greater in patients with involvement of the right coronary artery (2.1 +/- 1.1, SD) than in those with obstruction of the left anterior descending coronary artery (1.2 +/- 1.0, p less than 0.05). The time interval from the onset of symptoms of acute myocardial infarction to angiographic evaluation did not affect the extent of collateral visualization or the degree of coronary artery disease. These findings indicate that the collateral vessels develop after acute myocardial infarction regardless of the extent of coronary artery disease and accomplish the proliferative process within one month. It is also suggested that the collateral visualization is dependent on the size of perfusion territory of the infarct-related coronary artery.