Diagnosing PFO's

[StreetDoctor]

Forgive me if there are numerous topics on this. I'm planning on taking some advanced classes next spring and I want to get checked out for a PFO. I talked to my doctors assistant today who seemed familiar with PFO's and diagnosing them. I called asking to set up an appointment for a TEE to rule out a PFO. She stated that it's an invasive procedure and I can't get a TEE first and need to have an echocardiogram done first which will show whether or not I have a PFO (I believe that contradicts what I've read here?). I asked her about the echo not always showing a PFO and she said they'd be able to tell. Any advice here? I have an appointment for August 10th to have the echo done. I plan on bringing a printout in that talks about diving and PFO's but I have complete confidence in my doctor. He's an internal medicine doctor at Northwestern Memorial in Chicago and has been around for a long time.

 

[Saturation]

Primary Care Diving Medicine: More on PFO Screening

Get a transcranial doppler instead. If negative, it means no shunts of clinical significance are present, it won't say anything about the status of a PFO, just that it or any other shunt is not a source of gas shunting.

Gas shunting can change as you age, so getting tested and coming back negative today won't mean you won't suffer a shunt associated injury later.

http://igsaturation.blogspot.com/se...-max=2008-01-01T00:00:00-08:00&max-results=10

 

[StreetDoctor]

Primary Care Diving Medicine: More on PFO Screening

Get a transcranial doppler instead. If negative, it means no shunts are present, it won't say anything about the status of a PFO, just that its not a source of gas shunting.

Can you explain more. This is an excerpt from your link

"The transcranial Doppler is valuable only in positive tests, meaning a negative test does not mean you have no PFO."

 

[Saturation]

Can you explain more. This is an excerpt from your link

"The transcranial Doppler is valuable only in positive tests, meaning a negative test does not mean you have no PFO."

At the time the article was written it was unknown whether the PFO alone causes other reasons for DCS. Today its likely that DCS related issues are associated with gas emboli coursing through the PFO, and less than simply the PFO exists.

TCD only tests if gas emboli bypass the lungs and enter the arterial circulation. In DCS related issues, it can bypass the lungs through 3 key routes: an abnormal blood vessel anywhere in the body connecting veins to arteries like AVMs, an uncertain physiologic lung shunting by physical stress, or a PFO. In the resting state, AVMs and PFOs are the main culprit for bubbles bypassing the lungs, what is commonly called a 'right to left ' shunt, right has the vein, left has arteries deep inside the body. A TCD tests for all sources of shunts.

If the TCD study is negative, and if gas emboli are the only causes of DCS related issues with shunts, then even if you have a PFO, it likely will not cause an issue for now. However, the TCD does not test for the presence of a PFO. Bubbles that cross the PFO are related to the size of the hole and possible the pressure needed to push bubbles through the hole. So if you have a PFO, but its too small to be a concern, then the TCD test is negative. As you age, this hole could enlarge, and cause problems later in life.

 

[DandyDon]

This thread just came up and may be of some benefit: http://www.scubaboard.com/forums/di...uld-sport-diver-screened-pfo.html#post4893229