Looking for Divers with a PFO for a Research Study

[debersole]

Looking for Divers with a PFO for a Research Study

As many of you know, I am an interventional cardiologist with an interest in diving medicine. Along those lines, I close PFOs for selected divers who have suffered DCS (some of whom are members of this forum).

Petar DeNoble (of DAN) and I are coordinating a study of divers with PFO who have suffered DCS. It will include those who have had their PFO closed as well as those who have not. Our plan is to get a diving history and to follow these divers for several years.

If you might be interested in participating in this study or know someone who might be interested please PM me or email me at debersole@pol.net. (this includes those of you I’ve worked on previously!). I will gladly review the details of our investigation with you, show you the protocol (once we have it finalized), and go over the consent form.

Douglas Ebersole, MD
Watson Clinic LLP
1600 Lakeland Hills Blvd.
Lakeland, Florida 33805

[dgschott]

How do you feel about this? The incidence of DCS is so low that it makes PFO a moot issue. With the millions of divers with a PFO, there would be may thousands of cases of DCS, but there isn't. There is a robust literature on PFO risk in diving. It might be around 5:10,000 dives compared to 2:10,000 dives in someone without a PFO. Either number is extremely low. Given the complication risk of the closure procedure, there is a clear risk/benefit ratio that favors not closing the PFO in divers. Even with commercial divers, there is no indication to close a PFO. Peter Wilmsurst published a case series (lancet circa 1997) a while back of 6 commercial divers with recurrent symptoms who seem to have benefited from PFO closure, but there are many thousands of commercial divers without symptoms who don't need a procedure to prevent something that isn't happening. Do you recommend routine closure of a PFO in a diver who is asymptomatic on land? And a PFO is not a contraindication to diving based on current literature, correct?

Also, that occasional high risk PFO or commercial diver with some h/o decompression illness, an MRI of the brain to see if there are any silent lesions might help tip the decision one way or the other, but the problem is that studies in commercial divers show a lot of UBOs that are related to history of trauma and injuries sustained on the job not related to diving, so even the presence of UBOs on MRI are not helpful. It's likely that you would find as many MRI bright objects in commercial divers without a PFO as in those with a PFO. The only case that might make sense, and only from anecdotal reports, would be a diver with extreme exposures (with a high incidence of venous gas emboli), who had a history of recurrent cerebral events associated with diving. The prospective studies of crytpogenic stroke also provide some data that the PFO may not be the only cause.

[debersole]

All good points and I'm fully aware of all of the literature out there for DCS, cryptogenic stroke, etc. This is a very controversial issue which is why I think we need to gather what data we can.

The cryptogenic stroke issues are very confusing given the potential of hypercoaguable states confounding the data and the good therapeutic option of antiplatelet or anticoagulation therapy. While this may be effective in paradoxic emboli it is not helpful in paradoxic bubbles. There are several trials of cryptogenic stroke with PFO in progress but enrollment has been difficult, to say the least.

The increased risk of DCS for divers with PFO in the general (mainly recreational) diving community is about 2 fold (probably higher in technical or commercial divers), thus increasing a very small number (say, 3 in 10,000 dives) to another very small number (probably 6 in 10,000 dives). Hence, the power calculations easily show you could never do a randomized controlled trial to study this without tons of patients followed over many decades. This is simply not practical, either or scientifically or financially.

Anecdotally, however, there are lots of individuals who were having repetitive bouts of neurologic DCS (often from technical diving with large decompression stress) who have not had any further episodes since their closure. Arguably, the pleural of "anecdote" is "anecdotes" and not "data" but this information is still interesting nonetheless.

Our hope is to simply gather some data because, even though there isn't hard data to support it, there are divers getting PFOs closed. We hope to study their profiles and diving history before and after the procedure, see what complications they may have had from the procedure, and to follow those divers who have a known PFO but have elected not to have it closed. I think if we were to find continued bouts of DCS at the same rate as before closure in a given diver that would suggest we strongly consider not closing these defects in the future as would significant complication rates. We simply don't know the complication rate of this procedure in a relatively young adult non-stroke population.

I've been doing scientific research in cardiology for over twenty years and have authored approximately 50 papers in the cardiology literature, along with writing several book chapters. Granted, this is not the best scientific design but given the very low incidence of the "disease" and a very small population (probably 1/4 of the diving population has a PFO), it is the best we can do -- especially with EXTRMEMELY limited funding.

I appreciate your interest and suggestions. Thanks for your time and effort in putting together a very thoughtful post.

Doug

[debersole]

Thanks, everyone. I've gotten about 10-15 people who are interested so far. We're looking for about 50. If you or anyone you know would consider participating, let me know.

[MedCop]

Doug...

Sent you a PM, would be more than happy to participate.

BTW...those of you that don't know Dr. Ebersole closed my PFO.

Doug...I know I have said it many times to you and on various boards...but THANKS! You made it possible for me to continue diving at the level (and actually now beyond) that I so love.

Nathan

[scubagrunt]

.

Anecdotally, however, there are lots of individuals who were having repetitive bouts of neurologic DCS (often from technical diving with large decompression stress) who have not had any further episodes since their closure. Arguably, the pleural of "anecdote" is "anecdotes" and not "data" but this information is still interesting nonetheless.


Doug

yup what he said!!!!! i honestly dont really care what the "literature" says. i am a perfect example of a PFO closure that has made all the difference to me and my diving. after closure i have done way more aggressive dives and to this point have not had any "hits". if i did not have an understanding doctor i would not have been given this closure, due to the "literature"!! great work doug maybe you can change the literature and help other divers with this issue with doctors who dont share the same understanding!!
mel
one happy customer

ps if any of you need an understanding doctor about the PFO contact Doug. heck i flew clear accross the US to have mine closed with doug, and it was well worth the effort. not to mention he does great work

[debersole]

Nathan and Mel:

Thanks for your kind words. I'm just glad I could help and that you're both doing so well.

Doug

[debersole]

We've now got final IRB approval for the PFO study. The forms are ready to go out. I've sent PMs and emails to individuals who have contacted me. If you or anyone you know would be interested in participating, please email me at debersole@pol.net.

Thanks, everyone!

Doug

[debersole]

Just bumping this thread up a little.

We are still looking for divers with PFOs who have had decompression sickness. If you or anyone you know would qualify and are interested in participating, please let me know. It is hoped that the data we get from this study will help DAN make recommendations regarding the management of PFOs in divers in the future.

Here is a link to detailed information and all the forms you need.

www.diversalertnetwork.org/pfostudy

If anyone has further questions, please PM me here or email me at debersole@pol.net

Thanks!

Doug

[debersole]

"Bump" !!!



We are still looking for divers with a history of DCS who have been found to have a PFO. The study is designed to follow both divers who elected to have their PFO closed as well as those who have elected to be followed without closure. Details of the study and enrollment forms are at:

www.dan.org/pfostudy



Additionally, I will be speaking on "PFO and DCS" at the DEMA show in Orlando on November 3rd and 5th as well as at the NACD Conference in Gainesville, Florida on November 12.



Doug