What is the most common cause of pulmonary hypertension?

The most common cause of pulmonary hypertension is left heart failure. This condition leads to an increase in pulmonary venous pressure, causing the blood vessels in the lungs to constrict and resulting in pulmonary hypertension. Left heart failure can be due to various underlying causes, including ischemic heart disease, hypertension, and valvular heart disease.

While hypoxemic pulmonary vasoconstriction plays a role in the development of pulmonary hypertension, it is not the most prevalent cause. Hypoxemia can lead to vasoconstriction in the pulmonary circulation as a compensatory mechanism to divert blood flow to better-ventilated areas of the lungs, but the predominant causes of pulmonary hypertension are often linked to cardiac issues, particularly those stemming from the left side of the heart.

Chronic obstructive pulmonary disease (COPD) and pulmonary embolism also contribute to pulmonary hypertension through their mechanisms, but they typically do not occur as frequently as the effects seen from left heart failure. Understanding the interplay of these conditions is crucial for accurate diagnosis and treatment in patients with pulmonary hypertension.