NPPB and pulmonary arterial hypertension: One year survival of PAH has been shown to be influenced by a range of prognostic indicators including renal insufficiency, PAH associated with connective tissue disease, functional class III heart failure, mean right atrial pressure, resting systolic blood pressure, heart rate, 6-minute walk distance, brain natriuretic peptide levels, percentage predicted carbon monoxide diffusion capacity and pericardial effusion on echocardiogram13.