Coronary artery disease (CAD) results from what primary condition?

Coronary artery disease (CAD) primarily results from occluded coronary arteries due to atherosclerosis. Atherosclerosis is a process where fatty deposits, cholesterol, and other substances build up on the arterial walls, leading to the narrowing and hardening of the arteries. This narrowing restricts blood flow to the heart muscle, potentially resulting in chest pain (angina) or even heart attacks if the blood supply is severely compromised.

Understanding that CAD is specifically related to the condition of the coronary arteries is essential for recognizing its implications for cardiovascular health. In contrast, the other options do not directly address the primary pathological process behind CAD. For instance, decreased heart rate variability can indicate various health issues but is not a primary cause of CAD. Poor oxygen supply to the lungs might affect respiratory function but does not account for the occlusion of coronary arteries. Unstable angina attacks are symptoms resulting from CAD rather than the original condition leading to it. Thus, the primary cause of coronary artery disease is indeed occlusion of the coronary arteries due to atherosclerosis.