Right-heart catheterization is the most accurate, useful, and definitive diagnostic test for Pulmonary hypertension. This invasive diagnostic test directly measures pulmonary artery pressures, PVR, CO, and PCWP. A normal MPAP at rest is between 12 to 16 mmHg. A patient with a resting MPAP 25 mmHg is diagnosed with Pulmonary hypertension.