The anterior view of the heart and the cut-away view of the left ascending artery (LAD) showing the acute and chronic condition of a patient with a coronary artery occlusion. The acute condition of the patient shows 80-90% stenosis of the proximal diagonal branch of the LAD and an acute clot causing complete blockage of the distal diagonal collateral branch. The chronic condition of the patient shows total occlusion of the LAD and the collateral branch bypassing the chronic blockage of the LAD.