Pulmonary hypertension (PH) is a chronic disease of the pulmonary vasculature, characterized by vessel remodeling that leads to increased pulmonary vascular resistance, right ventricular failure, and ultimately, death. While PH is somewhat simply defined as a mean pulmonary artery pressure (mPAP) on right heart catheterization (RHC) of greater than or equal to 25 mm Hg, the clinical, pathobiologic, and physiologic manifestations of the disease, and its subsequent impact on an individual patient, vary greatly. For example, while PH is defined by an elevated mPAP, current guidelines classify PH into 5 major categories, each with numerous subcategories based on clinical and physiologic features.1 Accordingly, proper classification of an individual patient requires an extensive evaluation that includes pulmonary function testing, submaximal exercise testing, several imaging studies, overnight oximetry, echocardiography, and ultimately, RHC. PH, regardless of etiology, imparts significant burden on patients, causing severe functional limitations and negatively impacting survival. Historically, in the era prior to the availability of specific pulmonary vasodilator therapies to treat patients with the rarest form of PH, pulmonary arterial hypertension, median survival was around 2 years.2 With the advent of targeted medical therapies over the past 30 years, the median survival has improved to more than 7 years.3 However, with these advances in therapies and the expanding availability of lung transplantation for most forms of PH, the complexity of care for patients with this disease has increased exponentially.
