Pulmonary artery hypertension may be primary with an unknown cause or secondary to other conditions, including lung disease, sarcoidosis, collagen vascular disease, congenital heart disease, liver disease and thromboembolic disease. Treatment of primary pulmonary hypertension with warfarin anticoagulation, oral vasodilators and intravenous prostacyclin has been successful. Treatment of secondary hypertension with warfarin or oral vasodilators has been less successful.

McLaughlin and associates used long-term intravenous prostacyclin to treat patients with severe precapillary pulmonary hypertension associated with a variety of diseases. Pulmonary hypertension was defined by a mean pulmonary artery pressure on right-heart catheterization of greater than 30 mm Hg. Patients were excluded if they had any of the following conditions: hypoxia, restrictive lung disease with low total lung capacity, left ventricular ejection fraction of less than 50 percent, hypertensive heart disease, mitral valve disease or evidence of a clinical response to oral calcium channel blockers based on a vasodilator response to intravenous adenosine during cardiac catheterization.

Prostacyclin was administered continuously to 33 patients through a Hickman catheter with the dose adjusted on an outpatient basis according to the patient's symptoms. The causes of pulmonary hypertension in the study population were congenital heart disease (seven patients), collagen vascular disease (14 patients), sarcoidosis (two patients), peripheral thromboembolic disease (three patients) and portopulmonary hypertension (seven patients). All patients had severe symptoms.

Three patients died of primary disease complications before follow-up testing was done. Concurrent medications included warfarin in 94 percent of patients, diuretics in 94 percent of patients, digoxin in 76 percent of patients and calcium channel blockers (started before initiation of prostacyclin therapy) in 30 percent of patients. All patients had improvement in symptoms and in New York Heart Association class. Follow-up catheterization demonstrated reduced pulmonary artery pressure, improved cardiac output and decreased vascular resistance. The results were similar across underlying cause classes. Side effects related to prostacyclin use were common, including diarrhea, jaw pain, headaches and flushing. Three patients had an episode of sepsis.

The authors conclude that severe secondary pulmonary hypertension is a poor prognostic sign and may be treatable with intravenous prostacyclin, regardless of the cause of the increased pulmonary pressure, although patients with severe hypoxic lung disease or left-heart disease were not studied.