ACE, Angiotensin-converting enzyme; ARDS, acute respiratory distress syndrome; COPD, chronic obstructive pulmonary disease; IV, intravenous; PH, pulmonary hypertension.
Modified from Treprostinil (Remodulin) for pulmonary arterial hypertension. Med Lett. 2002;44:80-82; Sildenafil (Revatio) for pulmonary arterial hypertension. Med Lett 2005;47:165-167; Ambrisentan (Letairis) for pulmonary arterial hypertension. Med Lett 2007;49:87-90.
Other therapies include prostacyclins such as epoprostenol and treprostinil; both are pulmonary and systemic vasodilators but must be given by continuous intravenous infusion through an indwelling catheter or by subcutaneous injection (treprostinil). Iloprost is an inhaled form of prostacyclin apparently with fewer side effects that can improve exercise capacity and symptom scores, but it requires frequent dosing. Side effects and economic costs are significant obstacles to the use of all these agents. Bosentan is a nonselective endothelin receptor antagonist, and sitaxsentan is a selective endothelin receptor antagonist. Both improve functional status and physiologic measures in PH.
Sildenafil, which inhibits phosphodiesterase type 5 in the pulmonary vasculature, has also been approved for this indication based on results of a controlled trial that showed it improved 6-minute walk distance, New York Heart Association (NYHA) functional class, pulmonary artery pressure, cardiac index, and oxygenation. Sildenafil (2005) is also less expensive than the prostacyclins and endothelin receptor antagonists. Dipyridamole also has some phosphodiesterase type 5 activity.
Inhaled nitric oxide is a selective pulmonary vasodilator that is often used to treat persistent PH of the newborn. In adults with PH, a 2-year trial of inhaled nitric oxide therapy combined with dipyridamole demonstrated improvements in exercise capacity, symptoms, and hemodynamic measures. A European consensus panel has released guidelines for the use of nitric oxide in this condition.
Surgical therapies may be general (lung transplant) or specific, as in the repair of congenital shunting lesions, mitral stenosis, or atrial defects. Pulmonary thromboendarterectomy is effective in some patients with PH associated with saddle pulmonary embolus.
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