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Risk/Benefit of PFO Closure


The purpose of the study is to establish who is better off: divers with patent foramen ovale (PFO) who undergo closure and or divers with PFO who continue diving without the closure. The relative risk estimation will be based on combined incidence of adverse events due to decompression and due to the closure procedure. The risk/benefit estimation will be attempted based on comparison of incidence of decompression sickness (DCS) before the closure with the combined incidence of DCS and adverse events after the closure.

Decompression sickness in divers occurs due to the free gas (bubbles) forming in the body during or after decompression from diving. Bubbles may cause injury in the site of origin or in other body tissues if they enter the arterial circulation. Most bubbles are washed out from the site of creation into venous circulation and filtered out by lungs. In divers with PFO some bubbles may pass to the arterial system and cause symptoms of DCS.

The DCS risk in divers with PFO may be three to four times greater than in divers without PFO. The relative risk for DCS in divers with PFO increases with size of the patency and with the severity of the exposure. Some divers with PFO who suffer several episodes of DCS elect to undergo transcatheter PFO closure to reduce the risk of DCS while continuing diving. Some divers with diagnosed PFO continue diving regardless. Justification of PFO closure for divers is highly debated, and data on the risk/benefit of the closure in divers are not available.

How the Study Works

The trial will enroll 120 qualified participants with annual follow-up over five years. Participants must be 18 years of age or older, a certified diver with medical clearance for diving, undergone transcatheter PFO closure in past five years or diagnosed with PFO.

Prior to participation divers will be fully oriented to the study, and those who decide to participate will sign an informed consent form. Participants will complete a diving history questionnaire and provide medical documentation for the diagnosis of PFO and PFO closure. If during the study they undergo more tests and imaging regarding PFO, they will provide the results of those studies to the investigators of this study.

There is no inherent risk associated with participation in the study. Participants will dive according to their own schedule, but they will maintain a log of all their dives during the study, make available all electronic records from their dive computer and or closed-circuit apparatus for research, and report how they feel after each dive. Participants are responsible for maintenance of their dive equipment and for its proper function. It is their responsibility to follow safety procedures deemed necessary for a specific dive circumstances.

How to Volunteer

If you are 18 years or older and a certified diver who has been diagnosed with a PFO and has a clearance for diving, you may volunteer. Please download these forms:

  • Participant Informed Consent Form (PDF: 184 KB)
  • Study Enrollment Form (PDF: 23 KB)
  • Baseline Questionnaire (PDF: 91 KB)
  • Authorization Form (PDF: 39 KB)

  • Complete each form and mail it to:
    Douglas G. Ebersole, MD
    Watson Clinic LLP
    1600 Lakeland Hills Boulevard
    Lakeland, FL 33805
    Telephone: (863) 680-7973
    Dr. Ebersole or his associates may contact you by telephone if more information is necessary. If you qualify, you will receive a PFO study registration number and instructions on how to proceed.

    Periodic study updates will be published at this website.