**Core Concept**
Aortic dissection is a serious medical condition characterized by a tear in the inner layer of the aorta, leading to blood flow between the layers of the aorta, potentially causing aortic rupture or dissection. The management of aortic dissection involves pharmacological and surgical interventions to reduce blood pressure and prevent further dissection.

**Why the Correct Answer is Right**
The primary goal of pharmacological management in aortic dissection is to reduce blood pressure and prevent further dissection. This is typically achieved using vasodilators such as sodium nitroprusside, which acts on the endothelium to produce nitric oxide, leading to smooth muscle relaxation and vasodilation. The use of vasodilators in aortic dissection is based on the concept of reducing afterload, which in turn reduces the stress on the aortic wall and prevents further dissection.

**Why Each Wrong Option is Incorrect**
**Option A:** Beta blockers are not the first line of treatment for aortic dissection as they can increase afterload, which is undesirable in this condition.
**Option B:** Diuretics are not effective in managing aortic dissection as they do not directly affect the aortic wall or blood pressure.
**Option C:** Nitrates are not used as the first line of treatment for aortic dissection as they can cause reflex tachycardia, which can increase afterload and worsen the condition.

**Clinical Pearl / High-Yield Fact**
In the management of aortic dissection, it is essential to remember that vasodilators should be used in conjunction with beta blockers to achieve optimal blood pressure control and prevent further dissection.

**Correct Answer:** A. Sodium nitroprusside