Most common cause of Aortic dissection –
**Core Concept**
Aortic dissection is a serious medical condition characterized by a tear in the inner layer of the aorta, leading to a separation of the layers and potentially life-threatening complications. The most common cause of aortic dissection is hypertension, which increases the pressure within the aorta and causes it to stretch, leading to a tear in the intima.
**Why the Correct Answer is Right**
The mechanism of aortic dissection due to hypertension involves the increased pressure within the aorta causing it to stretch and potentially leading to a tear in the intima. This is often referred to as a "shearing force" that causes the intima to separate from the media and adventitia. The increased pressure within the aorta is a direct result of chronic hypertension, which is the most common cause of aortic dissection.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because while smoking is a risk factor for atherosclerosis, which can contribute to aortic disease, it is not the most common cause of aortic dissection.
**Option B:** This option is incorrect because while trauma can cause aortic dissection, it is not the most common cause.
**Option C:** This option is incorrect because while Marfan syndrome is a genetic disorder that can cause aortic dissection, it is a relatively rare condition and not the most common cause.
**Clinical Pearl / High-Yield Fact**
Chronic hypertension is the most common cause of aortic dissection, and it is essential to manage hypertension aggressively in patients with a history of aortic dissection.
**Correct Answer: A**. Hypertension.