ABSTRACT
The term primary pulmonary hypertension (PPH) was used by Dresdale in 1951, describing a hypertensive vasculopathy of pulmonary vessels of unknown cause. The process by which pulmonary vasculopathy is initiated results from the interaction of a predisposing state and one or more inciting stimuli, a concept known as the "multiple-hit hypothesis". This chapter explores the essential components of a complete hemodynamic assessment in pulmonary arterial hypertension (PAH). The purpose of evaluating PAH patients with a short-acting vasodilator is to determine the degree in which pulmonary vasoconstriction is contributing to the elevated pulmonary artery pressure (PAP). Vasodilator responsiveness identifies patients with a better prognosis and those who are more likely to have a sustained beneficial response to oral calcium channel blockers (CCBs). CCBs are recommended for patients who demonstrate responsiveness during acute vasodilator testing. PAH has become a major treatment focus with 10 approved drugs. Accurate diagnosis requires Right heart catheterization (RHC).
