Which cardiovascular condition is characterized by a weakening of a vessel wall?

• A. Aneurysm
• B. Varicose vein
• C. Thrombus
• D. Stenosis

Answer: (A)

Weakening of a vessel wall allows the wall to lose its structural strength and bulge under the pressure of circulating blood. This outward expansion is what defines an aneurysm. The wall becomes thinner and less able to withstand pressure, so an arterial segment can balloon and form a pouch that may rupture if it grows too large or is stressed by high blood pressure. By contrast, varicose veins are mainly about vein dilation from valve failure and increased pressure in the leg veins, not a primary wall weakening; a thrombus is a clot forming inside a vessel, potentially blocking flow; and stenosis is a narrowing of a vessel due to plaque or scarring. So the hallmark feature here is the weakened wall that bulges, i.e., an aneurysm.