Zeenat Safdar, MD, FCCP, FACP, FPVRI

1. What is the hemodynamic criteria used to define pulmonary arterial hypertension?

    At the Fourth World Symposium on Pulmonary Hypertension, the definition of pulmonary arterial hypertension (PAH) was updated as the mean pulmonary arterial pressure equal to or more than 25 mm Hg at rest, with a pulmonary arterial wedge or left atrial pressure equal to or less than 15 mm Hg. The exercise and pulmonary vascular resistance criteria were removed from this updated definition due to the poor availability of evidence. Right-sided heart catheterization (RHC) is the diagnostic gold standard to confirm PAH diagnosis. During the RHC, pulmonary artery pressures, right atrial pressure, right ventricle (RV) pressure, cardiac output, cardiac index, and pulmonary artery wedge pressures are measured; and vasodilator testing and shunt calculation (if indicated) are undertaken.

2. What are the usual physical findings in patients with pulmonary hypertension?

    The most common findings on physical examination include the following:

3. How is PAH classified?

    At the Fourth World Conference on Pulmonary Hypertension (held in Dana Point, Calif., in 2008), the term familial PAH was replaced by hereditary PAH, and schistosomiasis and chronic hemolytic anemia were added to Group 1 PAH. Current classification is outlined in Box 58-1. Pulmonary hypertension is classified as pulmonary arterial hypertension (Group 1), pulmonary hypertension resulting from left heart disease (Group 2), pulmonary hypertension resulting from lung diseases and/or hypoxia (Group 3), chronic thromboembolic pulmonary hypertension (CTEPH) (Group 4), and pulmonary hypertension with unclear multifactorial mechanisms (Group 5).

4. Is pulmonary hypertension a genetic disease?

    About 6% of patients with PAH have hereditary PAH. Mutations in the gene encoding bone morphogenetic receptor 2 (BMPR2) were found in approximately 70% of families with hereditary PAH and in 20% to 30% of patients with idiopathic PAH. Due to incomplete penetrance, most patients with this mutation never develop the disease. A subject with a mutation has a 10% to 20% estimated lifetime risk of acquiring PAH.

5. What should the clinical evaluation for possible pulmonary hypertension include?

    Evaluation should begin with a thorough history and physical examination. Possible causes of PAH should be addressed in the history. In addition, travel to or residence in an area endemic for schistosomiasis should be considered. All patients should receive a basic initial screening evaluation, consisting of collagen vascular disease serologic testing, human immunodeficiency virus (HIV) testing, hepatitis panel, chest radiograph, pulmonary function testing, ventilation-perfusion () scan, hypercoagulable work-up (if indicated), electrocardiogram, and echocardiogram.

    Patients with no clues to the cause on history or physical examination should be given a broad, detailed