Kaplan Meier Plots for Diastolic Pulmonary Artery Pressure to Pulmonary Capillary Wedge Pressure Gradient (DPG) in patients with pulmonary hypertension (PH) and an elevated pulmonary vascular resistance > 3 Wood units: a) 3mmHg, b) 5 mmHg, c) 7 mmHg, d) 10 mmHg.