ABSTRACT
Pulmonary arterial hypertension (PAH) is a rare and devastating disease characterized by a vasculopathy affecting the small pulmonary arteries, in the absence of other causes of pulmonary hypertension (PH) such as left heart disease, chronic lung disease, and thromboembolic disease. PAH is classified as group 1 PH under the updated clinical classification (Nice, France, 2013) (1). In 1891, Romberg provided the first report of this condition and recognized that pulmonary vascular disease (termed pulmonary arterial sclerosis at the time) was a cause of severe pulmonary hypertension (2). With the advent of right heart catheterization, Dresdale and colleagues, in 1951, published a case series describing in detail the clinical, hemodynamic, and pathologic features of primary pulmonary hypertension (3), a term that encompasses idiopathic, heritable, and drugs-and toxins-induced PAH in the modern-day classification system.
