Pulmonary hypertension is characterized by a progressive increase in pulmonary arterial pressure in association with dilatation and hypertrophy of the right ventricle, causing gradual reduction in ejection fraction. The increase in mean pulmonary arterial pressure may be passive, due to increased downstream pressure, hyperkinetic due to increased cardiac output, or due to increased pulmonary vascular resistance resulting from changes in the pulmonary vessels. In an advanced stage of pulmonary hypertension there may be right ventricular dilatation and hypertrophy, tricuspid regurgitation and septal deviation, with consequent effects on cardiac function. Clinical symptoms are not specific. Until recently, the treatment of pulmonary hypertension was limited to anticoagulation, supplementary oxygen and high-dose calcium channel blockers, in association with diuretics and digoxin where indicated. Recently approved treatments are nitric oxide, sildenafil--a phosphodiesterase-5 inhibitor, analogs of prostacyclin, and nonselective and selective endothelin receptor inhibitors. Surgery and anaesthesia pose a significant risk for patients with pulmonary hypertension. Right ventricular failure, persistent postoperative hypoxia and coronary ischaemia are among the potential postoperative complications.