Diagnosis, Treatment, and Clinical Management of Pulmonary Arterial Hypertension in the Contemporary Era

IMPORTANCE: Pulmonary arterial hypertension (PAH) is characterized by severe remodeling of the distal pulmonary arteries, increased pulmonary vascular resistance, and right ventricular dysfunction that promotes heart failure. Once regarded as largely untreatable, evidence-based decision making now guides clinical management of PAH and improves outcomes. However, misconceptions regarding the approach to PAH in the modern era are common and associated with substandard clinical care. OBSERVATIONS: The clinical profile of PAH has changed substantially since its original description. Patients are older at diagnosis than previously reported; disease severity appears greater in men compared with women; and patients with PAH in association with connective tissue disease are identified as a particularly high-risk subgroup. Risk stratification scales for PAH are now available at point of care, which inform treatment goals, including a 6-minute walk distance of greater than 440 m, peak volume of oxygen consumption of greater than 15 mL/min/kg, right atrial area of less than 18 cm2, cardiac index of greater than 2.5 L/min/m2, and absent or low symptom burden with routine physical activity. At present, 14 therapies targeting 6 PAH-specific molecular intermediaries are used clinically. Recent landmark trial data have demonstrated the critical importance of initial combination therapy in treatment-naive patients. These findings underscore a global shift in PAH that couples early disease detection with aggressive pharmacotherapy. Indeed, recent longitudinal data from patients receiving combination therapy show that the 3-year survival rate in PAH may be as high as 84% compared with 48% from the original National Institutes of Health registry on idiopathic PAH (1980-1985). Despite these gains, incomplete clinical evaluation and misdiagnosis by referring clinicians is common and associated with inappropriate therapy. CONCLUSIONS AND RELEVANCE: Compared with the original clinical experience, PAH has evolved into a contemporary and treatable disease characterized by improved survival and a high standard for defining therapeutic success. However, underawareness among clinicians regarding the importance of early and accurate PAH diagnosis persists and is a potentially reversible cause of adverse outcome in this disease.