Single vessel coronary artery disease has the highest mortality when it involves which artery?

• A. Collateral circulation
• B. The right coronary artery
• C. The left circumflex coronary artery
• D. The left anterior descending coronary artery

Answer: (D)

The amount of heart muscle at risk determines the danger of an artery occlusion, and the artery that supplies the largest territory to the left ventricle is the left anterior descending artery. It runs along the anterior interventricular groove and feeds most of the anterior wall and the interventricular septum. A proximal LAD occlusion infarcts a large myocardial area, causing extensive anterior wall damage, marked loss of left ventricular function, and a high risk of cardiogenic shock and fatal arrhythmias. This substantial territory at risk explains why single-vessel disease involving the LAD has the highest mortality. The right coronary artery and left circumflex can cause significant infarcts too, but their typical at-risk regions are smaller or more variable based on coronary dominance, so LAD occlusion carries the worst prognosis.