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The Cardiovascular Effects of Patent Foramen Ovale in Hypoxia

NCT07742540 · Status: NOT_YET_RECRUITING · Type: OBSERVATIONAL · Enrollment: 50

Last updated 2026-08-03

No results posted yet for this study

Summary

Before birth, the foramen ovale is a normal opening in the heart that allows blood to flow from the mother to the baby. After birth, this opening usually closes. However, in up to 38% of the population it does not fully close and is then called a patent foramen ovale (PFO). Having a PFO allows venous (blue) blood to mix with arterial (red) blood in the heart, which can lower blood oxygen levels. The mixing of blood has been suggested to be greater during exercise and with exposure to high-altitude. Also, people with a PFO may be a greater risk for severe altitude sickness, specifically involving the collection of fluid in the lungs which makes breathing very difficult - this is called high-altitude pulmonary edema (HAPE).

No study has directly measured the pressure difference across the heart which is required for the mixing of blood during exercise or at high-altitude. The present study will directly measure the pressure difference across the heart, as well as blood flow through the PFO during rest and exercise in simulated high altitude in adults with and without a PFO and a previous history of severe altitude sickness. The study will test the hypothesis that elevations in pulmonary artery pressure during exposure to hypoxia will not elicit a pressure gradient, and thus blood flow, across the PFO neither at rest nor during exercise.

Conditions

  • Patent Foramen Ovale (PFO)
  • High Altitude Pulmonary Edema

Sponsors & Collaborators

  • University of Texas Southwestern Medical Center

    lead OTHER

Principal Investigators

  • Benjamin D. Levine, M.D. · The University of Texas Southwestern Medical Center Dallas

Eligibility

Min Age
18 Years
Max Age
60 Years
Sex
ALL
Healthy Volunteers
Yes

Timeline & Regulatory

Start
2026-09-15
Primary Completion
2027-12-31
Completion
2028-09-15

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Read the full study record

This page highlights key information. For complete eligibility criteria, study locations, investigator contacts, and the full protocol, visit the original record on ClinicalTrials.gov.

View NCT07742540 on ClinicalTrials.gov