Secondary pulmonary arterial hypertension: treated with endothelin receptor blockade

Secondary pulmonary arterial hypertension (SPAH) is an adverse outcome of a variety of systemic disorders. These include collagen vascular diseases, chronic thromboembolism, human immunodeficiency virus, portopulmonary hypertension, and other diseases. Progression of SPAH may persist despite stabilization of the causative disease, thereby contributing to the poor quality of life and unfavorable survival in these patients. Treatment of the underlying cause and oxygen supplementation may alleviate symptoms, but no specific therapy to treat SPAH currently exists. Endothelin receptor blockade with bosentan has been shown to be beneficial in the treatment of primary pulmonary hypertension, but efficacy of this therapy in SPAH has not been established. We describe a case series of 6 patients with disparate causes of SPAH, who benefited from endothelin receptor blockade therapy. The causes of SPAH included collagen vascular disease (scleroderma) (1); systemic lupus erythematosus (2); chronic thromboembolic disease (2); and granulomatous vasculitis from sarcoidosis (1). Therapy with bosentan led to improvements in symptoms, New York Heart Association functional class, and walking distance in all patients. Distance walked in 6 minutes increased from a mean of 151.67 +/- 69.30 m at baseline to 314.83 +/- 89.09 m after an average of 14 months of bosentan treatment. Pulmonary arterial pressure decreased in most but not all 6 patients on follow-up echocardiography. This case series suggests a role for endothelin receptor blockade therapy in SPAH and should generate further interest in pharmacologic management of SPAH. A prospective controlled clinical trial of bosentan in SPAH is urgently needed.