Echocardiography and Respiratory Function Testing for Pulmonary Arterial Hypertension

Pulmonary hypertension (PH) is a hemodynamic and pathophysiologic condition characterized by elevated pulmonary artery pressure (PAP) and pulmonary vascular resistance (PVR), defined as an increase in the mean PAP of more than 20 mmHg at rest. PH can be a progressive and fatal disease if not treated appropriately. In the advanced stage of PH, the right ventricular (RV) function may be impaired, and it is associated with poor outcomes in PH. PH, however, can be easily misdiagnosed until the disease is at an advanced stage, because of its nonspecific and subtle symptoms in the early stages. PH is also a multi-factorial disease, it can be due to a primary elevation of pressure in the pulmonary arterial system alone (pulmonary arterial hypertension), or secondary to elevations of pressure in the pulmonary venous and pulmonary capillary systems (pulmonary venous hypertension). Establishing its etiology is also important for the early diagnosis of PH. Echocardiography is an important modality to assess the presence or absence of PH and its etiology, and it has been used to screen for this disease, determine the left and right heart structure and function, and assess the response to therapy in persons with PH. The pulmonary function test is also useful in PH, especially PH in chronic lung disorders. PH patients may also display mild to moderate ventilatory impairment in the absence of any evidence of lung airway or parenchymal disease, mainly in the form of airway obstruction. In this review, we discuss the diagnostic and prognostic role of clinical echocardiography and pulmonary function testing in clinical practice for pulmonary hypertension in this modern era.