Diagnosis and management of pulmonary arterial hypertension: Implications for respiratory care.

Pulmonary arterial hypertension (PAH) is a pathological condition of the small pulmonary arteries. PAH is characterized histopathologically by vasoconstriction, vascular proliferation, in situ thrombosis, and remodeling of all 3 levels of the vascular walls. These pathologic changes result in progressive increases in the mean pulmonary-artery pressure and pulmonary vascular resistance, which, if untreated, leads to right-ventricular failure and death. PAH can be associated with multiple conditions or risk factors (eg, collagen vascular diseases, liver disease, human immunodeficiency virus, congenital heart disease, or ingestion of certain medications or toxins) or it can be idiopathic. Up to 10% of the idiopathic cases are familial. Regardless of the etiology, the clinical presentation, histopathologic lesions, and response to therapy are all similar. Early in the disease process, the signs and symptoms of PAH are often subtle and nonspecific, making diagnosis challenging. Patients most often present with progressively worsening dyspnea and fatigue. An extensive evaluation is indicated to diagnose PAH, decipher its etiology, and determine long-term treatment goals. Transthoracic echocardiogram is an excellent screening tool to evaluate PAH, but every patient requires a right-side heart catheterization to help stage the disease and guide therapy. Prior to a decade ago, clinicians were only able to offer symptomatic therapy to this challenging group of patients. Earlier diagnosis, rapidly advancing understanding of the pathogenesis, and an increasing number of treatment options have changed the course of PAH, which was once thought to be invariably fatal.