Going tech - Patent Foramen Ovale (PFO) testing?

[irsubmarine]

The responses in this thread are gold!

So, the general consensus seems to be to wait for symptoms until you think about getting tested. I like this approach especially if I believe the idea that a PFO != DCI necessarily. Practically, I don't have time to book an appointment with a cardiologist before I start tech training anyway, so if I get bent, I'll get bent.

I would assume the degree of these symptoms is likely highly individualistic. The worst symptoms I ever remember having was doing 2 dives totaling about 140 minutes no deeper than 23 meters. No deco on either. I had to drive a long way and circumnavigate an island in order to avoid a high altitude pass and almost fell asleep at the wheel, though a stop in a town with a walk around woke me right up. I don't know if I was tired from the day before, if it was the freezing cold of the dive, etc etc. But it sounds pretty benign when compared to falling asleep, skin rashes and migraines all at once... What I mean to say is that it seems that you will probably know definitively when it is time to get tested for a PFO based on some of the other responses in this thread.

For me, one concern would be that since there are two people in my family with confirmed PFOs (non-divers) I assume myself or anyone with a similar family history would have a slightly higher risk of having it too. I discussed this with them and they told me that their cardiologist mentioned he could hear some type of murmur that indicated possible presence of a PFO and which was subsequently confirmed with an echo. Since no one has ever confirmed a similar murmur (I had a lot of checks when I was younger) I am hoping this would be a small, but perhaps negligible, indication that I would probably be fine (fingers crossed). I know echos and bubble studies are the golden standard from what I am reading, but it would be interesting to know if there is a semi-reliable indication for a lack of a PFO based on a lack of heart murmur.

I suppose the gravity of a confirmed PFO and DCS correlation is still a grey area when it comes to diving medicine? I.e. we need more data from more divers and incidents in order to gain more practically useful information as it pertains to tech diving?

 

[rjack321]

There is mixed evidence of PFOs being hereditary - its perhaps prudent to assume you have a PFO given your history...
Inheritance of persistent foramen ovale and atrial septal defects and the relation to familial migraine with aura
http://stroke.ahajournals.org/content/strokeaha/32/7/1563.full.pdf

But even if you knew today that you had a PFO, there's no much you could or should do differently class-wise - you aren't going to rush into heart surgery asymptomatically.

ps In addition to a cardiac shunt (aka PFO) you can also have pulmonary shunts. A pulmonary shunt is similar in that venous blood crosses to the arterial side - where any venous bubbles can cause the DCS problems. The transcranial Doppler may detect a pulmonary shunt while the TEE and TTE won't.

 

[mattia_v]

Generally, a PFO will not produce a murmur under normal circumstances - its basically a flap that hasn't grown shut after birth between left and right atria, and is kept closed unless you increase pressure in the chest cavity (coughing, heavy lifting, etc) which can briefly cause a shunt from right to left. If the hole is larger and open (which will generally be an ASD (atrial septal defect, a congenital anomaly) rather than a PFO, and there may be a murmur.

There is much ado about PFOs and closure in patients with stroke these days, but the studies are all flawed in some way, with more research required. And many are sponsored by closure device companies. And stroke is more serious and far more common than DCI, and the answers are still somewhat elusive.

Basically, I would view a PFO as a risk factor in people with DCI. Its significance remains in question. Whether to close is something to discuss with your doctor at that point.

 

[laikabear]

I got bent on most of my tech training dives, each time progressively worse. Insurance paid for the test and the closure, no issues since

BUT it was a very large hole and I have had a history of migranes that my physician used to justify the closure to insurance. The copay/deductible was still in the thousands. Totally worth it

25% of us have a PFO that never closed...a fraction of which will dive...and a fraction of those will have DCS symptoms as a result. I'd wait to see if it's an issue, keeping an eye out for any symptoms.

Good luck!

Do you get any fewer migraines now that you had the closure?

 

[Kevrumbo]

So, the general consensus seems to be to wait for symptoms until you think about getting tested. I like this approach especially if I believe the idea that a PFO != DCI necessarily. Practically, I don't have time to book an appointment with a cardiologist before I start tech training anyway, so if I get bent, I'll get bent. . . I suppose the gravity of a confirmed PFO and DCS correlation is still a grey area when it comes to diving medicine? I.e. we need more data from more divers and incidents in order to gain more practically useful information as it pertains to tech diving?

This was one of the questions put to the expert panel at the end of the TekUSA conference last weekend.

They were all very much against the screening for PFO in tech divers, and discouraged the getting a screen test. The same recommendation came from a conference on the subject a couple of years ago.

I exceptionally disagree with this expert panel, looking at it from the perspective of a hypothetical beginning tech diver starting training with an unknown -and unaware of- a PFO condition not previously discovered or diagnosed.

Again, it all comes down to a statistical/epidemiological vs clinical dilemma in a personal risk management perspective: a low probability event versus a severe health & welfare outcome if you unluckily suffered an acute DCI occurrence.

Here are the arguments:

https://www.diversalertnetwork.org/...Proceedings/2015-pfo-workshop-proceedings.pdf(see P.156):

"Epidemiological studies have shown an association between PFO and certain types of neurological and cutaneous decompression sickness. . . DCS risk has been reported as 3.6 cases per 10,000 dives, with 0.84 cases of neurological DCS per 10,000 dives, with a 4-fold increase in risk with PFO. . .Thus, if DCS cases were random events, the overall risk of neurological DCS is low, even in the presence of a PFO. . .

Statement 1

• Routine screening for patent foramin ovale (PFO) at the time of dive medical fitness (either initial or periodic) is not indicated. . .

Statement 2
Consideration should be given to testing for PFO under the following circumstances:

• A history of more than one episode of decompression sickness (DCS) with cerebral, spinal, vestibulocochlear, or cutaneous manifestations. . ."

However IMO and in disagreement with the above Statements, finding out you have a pre-existing PFO by potentially suffering a gross neurological type II DCS episode is neither a clinical best practice nor medically ethical if you could have screened for it beforehand with at least a simple noninvasive contrast TCD.

Dr. Richard Moon, Dept of Anesthesiology, Duke University Medical Center back in 1998 had the best unequivocally stated opinion and advice:

". . .For recreational divers I believe there is no need for a screening examination to look for a Patent Foramen Ovale (PFO). The only relationship we have found between PFO and DCI is for serious neurological bends, a rare disorder, and largely attributable to risk factors which are associated with the dive itself, such as depth, bottom time and rate of ascent. On the other hand, for a person who plans to perform dives that have a high risk of venous gas embolism for long periods of time, for example saturation diving [and especially with regard to present day long runtime open circuit or CCR decompression dives now becoming common to sport recreational advanced technical diving -bracketed italics mine @Kevrumbo ], then I would recommend a PFO Study. . ."

http://archive.rubicon-foundation.o...e/123456789/5949/SPUMS_V28N3_9.pdf?sequence=1
...
It's not about changing or debating academic viewpoints and position statements of leading hyperbaric scientists/physicians and statistical epidemiologists on an "expert panel", but for us laypeople to learn about and insist on making an informed decision regarding our own personal risk management threshold.

 

[Patoux01]

Do you mean you added that content in brackets yourself?

 

[PfcAJ]

ps In addition to a cardiac shunt (aka PFO) you can also have pulmonary shunts. A pulmonary shunt is similar in that venous blood crosses to the arterial side - where any venous bubbles can cause the DCS problems. The transcranial Doppler may detect a pulmonary shunt while the TEE and TTE won't.

Im not sure that’s accurate.

 

[Mouth Breather]

Do you get any fewer migraines now that you had the closure?

None so far, I had it closed in March of 2017. I also felt like it was a little easier to breathe.

 

[rddvet]

I got bent once at Ginnie with skin bends and some ocular signs (saw some starry spots and couldn't focus). In retrospect it had happened a couple times prior to but blew it off as suit squeeze or my harness being too tight. Then I got the same symptoms after some OW dives. I got tested for PFO and it was negative. I started buffering my shallow stops with extra time and really paid much closer attention to ascent rates. Haven't had a problem since and have done much longer dives without issue.

 

[laikabear]

None so far, I had it closed in March of 2017. I also felt like it was a little easier to breathe.

Meaning you used to get them how frequently? and since the closure you've not had any?? And you mean easier to breathe underwater???

Sorry to pry, but I get migraines a lot. A LOT. Many triggers identified, some not identified. I have had thousands of migraines over the past 25 years, and only 3 with an aura. All of the aura migraines occurred within the past 2.5 years (since I started diving). One was on the surface after a dive, one was on the ride home after a dive, and the other not temporally related to a dive. (The article someone linked mentioned a PFO link to migraine with aura, which really are the less common type of migraine).

I feel like I get more tired than most other divers after diving. I've never been bent. I feel better on and usually dive Nitrox but still get tired. But then again, I work nights, and have an erratic sleep schedule, so maybe I am more tired than most folks normally. I've had to pull over and take a power nap in the car after diving, on my 1-1.5 hr drives home, on a few occasions.

Anyway, not likely to run out and get tested for a PFO, but it's interesting.