Hemodynamics should be the primary approach to diagnosing, following, and managing pulmonary arterial hypertension.

Pulmonary arterial hypertension (PAH) is a highly morbid cardiopulmonary disease characterized by plexogenic pulmonary arteriole remodelling. Importantly, PAH severity correlates inversely with cardiac output and directly with pulmonary vascular resistance and right atrial pressure, illustrating the importance of accurately measured hemodynamics to define the clinical profile of patients. Currently available noninvasive technology offers only hemodynamic estimates. In contrast, right heart catheterization is the principle diagnostic procedure in PAH and is required to: (1) definitively exclude alternative pulmonary vascular diseases; and (2) quantify hemodynamics at baseline, after vasoreactivity testing, or in response to therapy to prognosticate outcome and guide therapeutic escalation.