ABSTRACT
Pulmonary hypertension may occur as “pulmonary arterial hypertension” (PAH), which is a rare dyspnea-fatigue syndrome with clear lungs and an isolated increase in pulmonary vascular resistance (PVR), or more commonly as a complication of chronic hypoxemic lung diseases, high-altitude exposure, left-heart conditions or pulmonary embolism (1). All these different types of pulmonary hypertension present with variable degrees of remodeling of the entire pulmonary arteriolar wall. Medial hypertrophy with variable adventitial changes dominates early PAH and purely hypoxic pulmonary hypertension. Intimal proliferation is prominent in chronic obstructive pulmonary disease (COPD). Plexiform lesions are pathognomonic of PAH but have been reported in some patients with chronic thromboembolic pulmonary hypertension (CTEPH). Proximal pulmonary arterial obstruction amenable to surgical endarteriectomy is an exclusive feature of CTEPH, which however also presents with peripheral arteriolar changes.
