Hi doctors, can you tell me what is primary pulmonary hypertension?

Primary/secondary: When the pressures in the arteries of the lungs are evaluated via left and right heart catheterization, and proven that the increased pressure in the lung circulation is due to the blood vessel problems themselves it is primary. If proven due to other causes as in heart failure, pulmonary embolus, copd, or pulmonary fibrosis then it is secondary.