## **Core Concept**
Pulse pressure is the difference between systolic blood pressure and diastolic blood pressure. In severe aortic regurgitation, the pulse pressure is significantly increased due to the backflow of blood from the aorta into the left ventricle during diastole.

## **Why the Correct Answer is Right**
In severe aortic regurgitation, a large volume of blood regurgitates back into the left ventricle during diastole, causing an increase in stroke volume. This increased stroke volume results in a higher systolic blood pressure. Simultaneously, the diastolic blood pressure drops because of the backflow of blood into the left ventricle. The pulse pressure, which is the difference between systolic and diastolic blood pressure, increases. The correct relationship is that the pulse pressure is approximately equal to the systolic blood pressure.

## **Why Each Wrong Option is Incorrect**
* **Option A:** This option suggests pulse pressure equals diastolic blood pressure, which is incorrect because pulse pressure is the difference between systolic and diastolic blood pressures, not equal to diastolic blood pressure.
* **Option B:** This option suggests pulse pressure equals mean arterial pressure, which is incorrect because mean arterial pressure is the average pressure in the arteries during one cardiac cycle and does not directly relate to the widened pulse pressure seen in aortic regurgitation.
* **Option C:** This option is not provided but based on the correct answer, any option not stating pulse pressure equals systolic blood pressure would be incorrect.

## **Clinical Pearl / High-Yield Fact**
A classic clinical sign of severe aortic regurgitation is the widened pulse pressure. This can be remembered by the physical examination finding of a "water-hammer pulse" or Corrigan's pulse, which is a bounding pulse.

## **Correct Answer:** .