Which group of pulmonary hypertension is characterized by a mean PAP greater than 25 mmHg and a PCWP less than 15 mmHg?

The group characterized by a mean pulmonary artery pressure (PAP) greater than 25 mmHg and a pulmonary capillary wedge pressure (PCWP) less than 15 mmHg is primary pulmonary arterial hypertension. This condition specifically arises from the vascular aspect of the lungs, where increased pressure occurs due to narrowed or blocked pulmonary arteries, and is independent of left heart dysfunction.

In primary pulmonary arterial hypertension, there is no evidence of left heart disease contributing to the elevated pressures. The distinction of having a PCWP less than 15 mmHg is critical, as it helps differentiate this type from pulmonary hypertension due to left heart disease, where elevated PCWP would be observed due to heart failure processes. The identification of primary pulmonary arterial hypertension is essential for appropriate diagnosis and treatment, as it has different management strategies compared to other forms of pulmonary hypertension.