Effect of Bosentan on Exercise Capacity at High Altitude

Phase 1

Completed

• Conditions: Altitude; Pulmonary Hypertension

• Registration Number: NCT00432978
• Lead Sponsor: VA Loma Linda Health Care System

Brief 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.

Detailed 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 Timeline

• Study Start: 2006-07
• Study Completion: 2007-02
• Study First Submitted: 2007-02-06
• Study First Submitted QC: 2007-02-06
• Study First Posted: 2007-02-08
• Status Verified: 2007-04
• Last Update Submitted: 2007-04-17
• Last Update Posted: 2007-04-18

Recruitment & Eligibility

• Status: COMPLETED
• Sex: All
• Target Recruitment: 20

Inclusion Criteria

• Normal healthy subjects aged 18 - 55 years

Exclusion Criteria

• Pregnancy
• Heart, lung or liver disease
• Use of glyburide, cyclosporin A

Study & Design

• Study Type: INTERVENTIONAL
• Study Design: CROSSOVER

Primary Outcome Measures

Name	Time	Method
Exercise Capacity
Pulmonary artery systolic pressure

Secondary Outcome Measures

Name	Time	Method
Hemoglobin oxygen saturation

Trial Locations

Locations (1)

VA Loma Linda Healthcare System; 🇺🇸 Loma Linda, California, United States