Spironolactone for Pulmonary Arterial Hypertension

Pulmonary Arterial Hypertension

Magnetic Resonance Imaging

Background: \- High blood pressure in the lungs, known as pulmonary arterial hypertension (PAH), is a rare disorder. In spite of recent advances in treatment, the death rate remains unacceptably high. Lung blood vessel function can be harmed by progressive injuries, such as inflammation, leading to worsening of the disease. A drug called spironolactone has been known to improve blood vessel function and reduce inflammation. Some people with PAH take spironolactone to help treat fluid retention. However, its effect on inflammation and blood vessel function in patients with PAH is not known. Researchers want to see if spironolactone can help these conditions in people with PAH. Objectives: \- To test the effectiveness of spironolactone in treating pulmonary arterial hypertension. Eligibility: \- Individuals at least 18 years of age with pulmonary arterial hypertension. Design: * This study will last for 24 weeks. Participants will be screened with a physical exam and medical history. Blood and urine samples will be collected. * Participants will take either spironolactone or a placebo. They will take their study drug or placebo for 7 weeks. Treatment will be monitored with regular blood tests. * In Week 8, participants who have had no reaction to the treatment will receive a higher dose of the drug or placebo. * In Week 12, participants will have a study visit with heart and lung function tests. They will also have a 6-minute walk test, and provide blood and urine samples. * After additional study visits for blood samples, participants will have a final visit in Week 24. The tests from Week 12 will be repeated at this visit.

INTRODUCTION: Pulmonary arterial hypertension (PAH) is a rare disorder associated with poor survival. Endothelial dysfunction resulting from 1) genetic susceptibility, and 2) a triggering stimulus that initiates pulmonary vascular injury, the "two-hit" hypothesis, appears to play a central role both in the pathogenesis and progression of PAH. Inflammation appears to drive this dysfunctional endothelial phenotype, propagating cycles of injury and repair in genetically susceptible patients with idiopathic PAH (IPAH) and patients with disease-associated PAH. Therapy targeting pulmonary vascular inflammation to interrupt cycles of injury and repair and thereby delay or prevent RV failure and death has not been tested. Spironolactone, a mineralocorticoid receptor (MR) and androgen receptor (AR) antagonist, has been shown to improve endothelial function and reduce inflammation. Current management of patients with severe PAH and NYHA/WHO class IV symptoms includes use of MR antagonists for their diuretic and natriuretic effects once clinical right heart failure has developed. We hypothesize that initiating therapy with spironolactone at an earlier stage of disease in subjects with PAH could provide additional benefits through anti-inflammatory effects and improvements in pulmonary artery endothelial function. OBJECTIVES: Patients with IPAH and disease-associated PAH will be recruited to the NIH and enrolled in a randomized, double blinded, placebo-controlled study of early treatment with spironolactone to investigate its effects on exercise capacity, clinical worsening, and vascular inflammation in vivo. METHODS: The total number of PAH subjects enrolled will be up to 70. Subjects will undergo 1) standard clinical examinations including 6-minute walk distance and echocardiography; 2) cardiopulmonary exercise testing; 3) plasma profiling of inflammatory and neurohormonal markers; 4) gene expression profiling of peripheral blood mononuclear cells (PBMCs); and 5) high-resolution MRI-based determination of pulmonary vascular and RV structure and function. Safety and tolerability of spironolactone in PAH will be assessed with periodic monitoring for hyperkalemia and renal insufficiency as well as the incidence of drug discontinuation for untoward effects.

United States