Not seen in primary pulmonary hypeension-
**Core Concept**
Primary pulmonary hypertension (PPH) is a rare and fatal disease characterized by elevated pulmonary artery pressure without any identifiable cause. It is distinct from secondary pulmonary hypertension, which is caused by other conditions such as left heart disease, chronic lung disease, or thromboembolic disease. The pathophysiology of PPH involves vascular remodeling, endothelial dysfunction, and abnormal proliferation of pulmonary artery smooth muscle cells.
**Why the Correct Answer is Right**
The correct answer to this question is related to the characteristic features of primary pulmonary hypertension. One of the key distinguishing features of PPH is the absence of any underlying cause or secondary condition that could explain the elevated pulmonary artery pressure. This is in contrast to secondary pulmonary hypertension, where an identifiable cause can be found. The diagnosis of PPH relies on the exclusion of other possible causes of pulmonary hypertension.
**Why Each Wrong Option is Incorrect**
**Option A:** Not a characteristic feature of primary pulmonary hypertension. While some secondary causes of pulmonary hypertension may present with a similar clinical picture, they are not considered primary pulmonary hypertension.
**Option B:** This option is incorrect because it is a common feature of primary pulmonary hypertension. Pulmonary artery endothelial dysfunction is a key component of the pathophysiology of PPH.
**Option C:** This option is incorrect because it is a characteristic feature of primary pulmonary hypertension. Pulmonary artery smooth muscle cell proliferation is a hallmark of vascular remodeling in PPH.
**Clinical Pearl / High-Yield Fact**
In the diagnosis of primary pulmonary hypertension, it is essential to exclude secondary causes of pulmonary hypertension, including left heart disease, chronic lung disease, and thromboembolic disease. This is typically achieved through a thorough clinical evaluation, imaging studies, and invasive hemodynamic measurements.
**Correct Answer: D.**