What condition is characterized by the narrowing of the aortic valve?

Aortic stenosis is characterized by the narrowing of the aortic valve, which restricts blood flow from the heart into the aorta and onward to the rest of the body. This narrowing can occur due to a congenital defect, calcium buildup on the valve over time, or age-related changes in the valve structure. As a result, the heart has to work harder to pump blood through the narrowed opening, leading to symptoms such as chest pain, fatigue, and shortness of breath, especially during physical activity.

In contrast, aortic regurgitation involves the aortic valve not closing properly, allowing blood to flow backward into the heart. Mitral valve prolapse is a condition affecting the mitral valve, leading to its improper closure, which does not pertain to the aortic valve. Lastly, pulmonary hypertension refers to elevated blood pressure in the pulmonary arteries and is not directly related to the aortic valve itself. Thus, the distinguishing feature of aortic stenosis is the direct narrowing of the aortic valve, which defines its clinical presentation and associated symptoms.