Effect of Bosentan on Exercise Capacity at High Altitude

Pulmonary Hypertension Clinical Trial

Official title: Effect of Bosentan on Exercise Capacity at High Altitude

Status Completed

Clinical Trial Summary

This study is to determine whether bosentan will alter exercise capacity after rapid ascent to high altitude.

We hypothesize that bosentan administration will improve arterial oxygenation and exercise capacity.

Clinical Trial Description

Both the prostacyclin and the nitric oxide pathways are important in modulating hypoxic pulmonary vasoconstriction (HPV). There is little information about the role of the endothelin pathway at high altitude. The endothelin pathway involves the activation of two distinct receptors, A and B. Bosentan is a nonpeptide, specific, competitive, dual antagonist of both endothelin receptor subtypes. The primary objective of this study will be to determine the effect of endothelin receptor blockade with bosentan on exercise performance and HPV. This is a prospective, double blind, placebo-controlled, randomized cross-over study involving healthy subjects aged 25-55 years of age. Subjects will undergo echocardiography and exercise testing at low altitude (< 500m) and at 3800m. Subjects will receive either bosentan vs. placebo and will be studied at low and high altitude on two occasions in a crossover design. Primary outcome measures will be pulmonary artery systolic pressure measured by echo-Doppler and exercise capacity. A better understanding of the role of the endothelin pathway in HPV may lead to improved treatments for some patients. ;

Study Design

Allocation: Randomized, Endpoint Classification: Pharmacodynamics Study, Intervention Model: Crossover Assignment, Masking: Double-Blind, Primary Purpose: Treatment

Related Conditions & MeSH terms

• Altitude
• Hypertension, Pulmonary
• Pulmonary Hypertension

• NCT number: NCT00432978
• Study type: Interventional
• Source: VA Loma Linda Health Care System
• Status: Completed
• Phase: Phase 1
• Start date: July 2006
• Completion date: February 2007