Schematic representations of pulmonary hypertension. (A) Schematic cross-sectional representation of a normal pulmonary arteriole and a pulmonary arteriole affected by pulmonary hypertension. (Adapted from Pugliese et al.⁷ ) (B) Schematic representation of site of initiation of elevated pulmonary arterial pressure of precapillary pulmonary hypertension, postcapillary pulmonary hypertension, and CTEPH. L.V., left ventricle; PH, pulmonary hypertension; R.A., right atrium; R.V., right ventricle.