Collateral circulation from the conus coronary artery to the anterior descending coronary artery: assessment using multislice coronary computed tomography.

The prognosis of patients with coronary artery disease largely depends on the presence of a collateral circulation. The location and extent of the collateral circulation is highly variable and these parameters determine whether or not ischemic symptoms occur and whether left ventricular contractility is abnormal. The collateral circulation is generally established through small-caliber distal vessels, although many different forms have been described. We report on three patients with severe left coronary artery disease and collateral circulation through a large conus coronary artery that joined a proximal or medial segment of the left anterior descending coronary artery. In all three cases, left ventricular function was preserved.