Vascular occlusions are most commonly caused by which condition?

• A. Atherosclerosis and embolus
• B. Chronic hypertension
• C. Cerebrovascular accidents
• D. Air embolus

Answer: (A)

Vascular occlusions arise most often from atherosclerotic disease in which plaques narrow and stiffen arteries, and can rupture to trigger thrombus formation that blocks flow. In addition, emboli—clots or debris traveling from the heart or large arteries—can lodge downstream and cause a blockage. This combination—plaque buildup with possible embolic events—is the most frequent mechanism behind vascular occlusion because atherosclerosis underlies many arterial blockages and embolization can convert a partial narrowing into a complete occlusion. While chronic hypertension damages vessels and ischemic strokes are a consequence of occlusion, they are not the primary immediate causes in the same way plaque-related thrombus formation and distal embolization are. Air emboli are possible but much less common.