Role of Vasodilator Testing in Pulmonary Hypertension

Pulmonary hypertension is clinically defined by a mean pulmonary artery (PA) pressure of 25 mm Hg or more at rest, as measured by right heart catheterization. To identify patients who are likely to have a beneficial response to calcium channel blockers (CCBs) and therefore a better prognosis, acute vasodilator testing should be performed in patients in certain subsets of pulmonary arterial hypertension (PAH). A near normalization of pulmonary hemodynamics is needed before patients can be considered for therapy with CCBs. Intravenous adenosine, intravenous epoprostenol, inhaled nitric oxide, or inhaled iloprost are the standard agents used for vasoreactivity testing in patients with idiopathic PAH. In this review we describe the various aspects of vasodilator testing including the rationale, pathophysiology and agents used in the procedure.