Which of the following is a cause of passive pulmonary hypertension?

Passive pulmonary hypertension occurs when there is increased pressure in the pulmonary circulation due to left-sided heart conditions that lead to an increase in left atrial pressure. Mitral stenosis is a significant cause of passive pulmonary hypertension because it involves narrowing of the mitral valve, which hinders blood flow from the left atrium to the left ventricle. As a result, blood can back up into the pulmonary veins, leading to increased pressure within the pulmonary circulation.

This elevated pressure causes the pulmonary arteries to constrict, further exacerbating the hypertension. In the case of mitral stenosis, the obstruction leads to a pressure overload in the pulmonary system, manifesting as symptoms associated with pulmonary hypertension, such as shortness of breath and fatigue.

The other conditions listed either do not primarily cause passive pulmonary hypertension or involve mechanisms that lead to primary pulmonary hypertension rather than passive resistance. Understanding the hemodynamics involved is crucial for recognizing the impact of mitral stenosis on pulmonary blood flow and pressure.