Effects of Iloprost on Hypoxic Pulmonary Vasoconstriction and Exercise Capacity at High Altitude

Hypoxic Pulmonary Vasoconstriction Clinical Trial

Official title: Effects of Iloprost on Hypoxic Pulmonary Vasoconstriction and Exercise Capacity at High Altitude

Status Recruiting

Clinical Trial Summary

The objective of this study is to determine if single dose administration of inhaled iloprost will reduce pulmonary artery pressure, reduce hypoxic pulmonary vasoconstriction and improve arterial oxygenation at rest and during exercise at high altitude.

Clinical Trial Description

Three major pathways in addition to oxygen modulate pulmonary vascular tone: 1) nitric oxide, 2) endothelin, and 3) prostacyclin. Considerable animal data support the role of the prostacyclin pathway in modulating hypoxic pulmonary vasoconstriction. In humans, prostacyclin and its analogs are important therapeutic agents in the treatment of pulmonary arterial hypertension (PAH). Despite the animal data and human data in PAH there is very little information about the use of iloprost to relieve hypoxic pulmonary vasoconstriction in healthy humans. Inhaled iloprost is an ideal agent to study the prostacyclin pathway due to its short duration of action (30-90 min) and elimination half-life of only 20-30 min. Individuals already participating in the Nepal Medex 2008 trip will be invited to participate in this research. Participants will be healthy active females or males, between 18-80 years of age, without known pregnancy or liver disease, who have a readily measurable tricuspid regurgitant velocity by Doppler echocardiography. If possible, we will attempt to identify a cohort of HAPE susceptible patients. Participants will undergo evaluation both at sea level (baseline) and at high altitude. Baseline (low altitude) testing will be performed in Bangor, North Wales, UK, and will include evaluation of pulmonary artery systolic pressures, cardiac output, and oxygen saturation at rest and during submaximal exercise before and after inhalation of iloprost. This strategy will then be repeated at an altitude of approximately 5000 meters in the Dhaulagiri region of Nepal. ;

Study Design

Allocation: Randomized, Endpoint Classification: Efficacy Study, Intervention Model: Crossover Assignment, Masking: Double Blind (Investigator, Outcomes Assessor), Primary Purpose: Basic Science

Related Conditions & MeSH terms

• Hypoxic Pulmonary Vasoconstriction

• NCT number: NCT00708565
• Study type: Interventional
• Source: VA Loma Linda Health Care System
• Status: Recruiting
• Phase: Phase 1
• Start date: July 2008
• Completion date: October 2008