Pulmonary hypertension is primarily a result of which alteration?

Pulmonary hypertension primarily arises from narrowed pulmonary capillaries. This condition is characterized by an increase in blood pressure within the pulmonary arteries, which can occur due to various factors but is significantly influenced by changes in the small blood vessels of the lungs. When the pulmonary capillaries become narrowed or obstructed, this leads to increased resistance to blood flow, causing the right side of the heart to work harder to pump blood through the lungs. Over time, this increased workload can lead to right heart failure.

The narrowing of the pulmonary capillaries can result from various underlying conditions, such as pulmonary vascular remodeling, culminated by smooth muscle cell proliferation and changes in the endothelial cells lining the blood vessels. These alterations can be triggered by various factors, including chronic hypoxia, inflammatory processes, or genetic predispositions. In summary, the primary alteration leading to pulmonary hypertension is the narrowing of the pulmonary capillaries, which directly affects blood flow and pressure within the pulmonary circulation.