Disclaimer: This website does not provide medical advice
The information on this website is solely intended for educational purposes. It is not intended to be a substitute for professional medical advice, diagnosis, or treatment. Always seek advice from your physician or other qualified healthcare provider with any questions you may have regarding your health. Never delay seeking medical advice because of something you have read on this website. As a non-physician, this article is based solely on my personal experience and observations with my own PFO.
How my PFO was diagnosed
During a tech diving course, while sitting in the dive base filling the tanks, we talked about future diving ambitions. In that discussion, our own medical experiences came up. One such experience was that after several days of deep dives within no-decompression limits on a liveaboard, I developed tinnitus in my left ear that would not go away. I saw an ENT doctor directly after getting home. He prescribed a hearing test, but everything was normal. In my ear was a constant, very annoying chirping though. Over time, that chirping got a little better, but I did not associate it with decompression sickness (DCS) because I had been diving within the limits of the Bühlman model. However, in our discussion, it was suggested that I undergo testing for a PFO due to my ear issue and my interest in rebreather diving.
There are currently two main methods to diagnose a PFO. The standard, less invasive method is a Transcranial Color Doppler (TCD): Saline solution is injected into the right arm. If a connection between the heart’s right and left atrium is present (called a shunt), microbubbles can be seen in the ultrasound. The degree of shunting can be determined by the number of bubbles that shunt from the right to the left atrium from the venous directly into the arterial circulation bypassing the lungs. In some cases, a flap covers the PFO and only permits shunting under strain, e.g. by performing a Valsalva maneuver. This flap is formed by the primum and secundum atrial septa. Typically, it only opens when the pressure in the right atrium exceeds that in the left. About 25% of all people have a PFO with varying degrees of shunting. In my case, the PFO was functionally open, so even when I breathed normally, there was shunting. When I just strained a little bit, the physician could see a curtain of bubbles on the ultrasound monitor.
Impact of a PFO on diving
Once you are diagnosed with a PFO, you have three choices:
- Stop diving
- Low bubble diving
- PFO closure
I quickly ruled out quitting diving. Low-bubble diving was a possibility. Depending on the size and nature of the PFO, it is essential to minimize the formation of DCS-inducing microbubbles. Some low-bubble diving strategies include:
- Plan your dive, dive your plan
- Limit diving to two dives per day
- No decompression diving
- Adhere to the no-decompression limit time
- Keep repeat dives shallower than preceding dives
- Extend the duration of safety stops in 5 m depth from 3 minutes to 5-10 minutes
- Reduce the ascent speed, particularly on the last 10 m before surfacing
- Increase the duration of surface intervals
- Use nitrox with air settings on the dive computer (while not exceeding the maximum depth of the nitrox mix)
- Avoid risk factors, e.g. dehydration, cold, and smoking
- Avoid strenuous situations at the end of dives, e.g. carrying equipment, difficult exits, strong currents
- No exertion in the first few hours after diving, e.g. carrying heavy items, sports
Even with these precautions, there is no guarantee that DCS incidents won’t occur. Divers with significant shunting may still be at a higher risk for DCS, particularly cutaneous DCS (“skin bends”), even when following these strategies. That said, clinical DCS events are rare. DAN statistics show that only 3-4 cases of DCS occur per 10,000 recreational dives when divers adhere to safe diving protocols.
The third option is PFO closure. Three surgery options are available as of writing this article:
- Open heart surgery
- Closure via heart catheter using an occluder device
- Closure via heart catheter using NobleStitch (a stitch is used to close the PFO)
The riskiest option is open heart surgery. Since that was never an option for me, I will focus on the latter two techniques.
Occluder devices are made from NiTinol—a memory metal composed of nickel and titanium—and consist of non-permeable disks on either side. These are inserted into the heart, with one side unfolding in the left atrium and the other unfolding in the right to seal the PFO. Once in place, the occluder device is released and becomes endothelialized (covered by tissue) over time.
The NobleStitch technique is similar to the occluder device method, but instead of inserting a device, a stitch is used to close the PFO, eliminating the risk of nickel allergies or potential occluder dislodgment.
After consulting with several physicians, I opted for heart catheter closure. It is more important to find a physician you trust than to focus on which device you would prefer. Only the physician will be able to make a suitable selection based on your anatomy. Sometimes, a couple of devices are tried out during the actual surgery because the initial selection turns out to be unsuitable.
The actual surgery
Before surgery, additional tests were conducted. One of these was an exercise electrocardiogram (ECG) under ultrasound. The pre-surgery preparation also included a detailed consultation about the potential life-altering consequences of the procedure. During the consultation, it became clear that NobleStitch was not my physician’s preferred option due to its lower success rate on the first attempt compared to an occluder device—largely because of my PFO’s anatomy.
The closure procedure itself was scheduled for a Friday, with plans for me to stay overnight in the hospital. You will be asked to shave the area around your groin prior to the operation, as this is where the catheter will be inserted. It’s also a good idea to bring books, audiobooks, or movies because you won’t be allowed to get up for several hours post-surgery.
Note that you’ll be instructed to refrain from eating or drinking (aside from small sips of water) before the procedure. One of the pre-surgery preparations included a heparin drip to anticoagulate my blood. Once in the operating theater, I moved myself to the operating table. The surgical team greeted me, and we briefly discussed what to expect during the procedure. I was then covered with surgical drapes that left only my groin and face exposed. A local anesthetic was applied to the groin, and the catheter was inserted. Remarkably, the catheter reached my heart before I was even aware of it. There are no pain receptors inside the heart, so I found it fascinating to watch the catheter’s progress on the angiography (a special kind of X-ray that uses contrast agent to show blood vessels) monitor.
Next, I was given numbing spray for my throat and fitted with a mouthpiece to prepare for a Transesophageal Echocardiogram (TEE). For a TEE, an ultrasound probe is inserted into the esophagus to obtain high-resolution images of the heart. After the spray and mouthpiece were in place, I was anesthetized for the remainder of the procedure, so I have no memory of what happened after that.
Immediately after the surgery
When I woke up, the operating room was almost empty, with just one nurse there to help me onto my bed and wheel me back to my room. Not long after, another nurse came in to check the surgical site and noticed significant bleeding at the groin. They quickly performed an ultrasound to make sure there wasn’t any internal bleeding. To stop the bleeding, they placed a sandbag on the area, which meant I had to stay still for a few more hours. While the discomfort wasn’t too bad, being stuck in bed without moving for that long was frustrating. Because of the bleeding, the nurses checked on me more often. Even though I had to stay lying down, it was still important to drink lots of fluids to flush out the angiography contrast agent. Thankfully, the nursing staff was well-prepared and took great care of everything, so there was no need to worry.
By the next morning, I felt considerably better and was allowed to move around a little. The stitches in my groin were removed, but I could still feel a small, round object under my skin. This was the resorbable closure device (likely an AngioSeal or Perclose) used to seal the vein after the catheterization. Once all the checkups were completed, I was discharged and allowed to go home. It felt great to go home again!
In 2023, the German hospital charged my insurance a total of €10,119 for the PFO closure procedure, which included one overnight stay in a double room. Follow-up appointments were billed separately.
Follow-ups
During the initial follow-ups, which also involved TEEs, it was clear that the closure was incomplete, and bubbles were still shunting under strain. In many cases, it takes six months for the occluder device to be sufficiently endothelialized to prevent shunting. At one point, I had to visit the hospital for stitches after accidentally cutting myself, as I was still on Clopidogrel and Aspirin. In hindsight, I could have probably stopped the bleeding using Celox or QuikClot, which I began carrying with me until I could stop the anticoagulants. At my six-month follow-up, the PFO finally remained closed, even under strain, and I was cleared to dive again!
Interestingly, my exercise tolerance improved significantly after the closure. Before the procedure, I would become short of breath relatively quickly when exercising, especially when my heart rate reached around 135. Post-closure, I am able to sustain a heart rate of 140 for extended periods and even push myself further during workouts. Looking back, I would get my PFO closed again without hesitation.
Resources and further reading
Validation of algorithms used in commercial off-the-shelf dive computers
This study compares real-world results with the calculation outputs from common dive computer algorithms. Surprisingly, only two commonly used algorithms align with real-world data, raising questions about the reliability of other models for safe diving practices.
Divers Alert Network (DAN) provides an overview of PFOs, including their anatomy, prevalence, and associated risks for divers. This resource is particularly useful for understanding how PFOs can increase the risk of decompression sickness (DCS).
Risk Mitigation for Divers With a Known PFO
This guide from DAN outlines practical protocols and safety measures for divers who have been diagnosed with a PFO, helping reduce the risk of decompression sickness. It includes steps like modifying dive profiles and enhancing post-dive recovery.
Interventional closure of patent foramen ovale
Written by the Polish Cardiac Society, this article explains when PFO closure is necessary, reviews various closure techniques, and discusses the training required for physicians to perform these procedures. This resource is helpful for those considering medical intervention for their PFO.
This doctoral dissertation explores the use of occluder devices for Atrial Septal Defect (ASD) closure, a condition closely related to PFO. The detailed animal studies provide insights into how these devices work inside the heart and their long-term outcomes.
Recent developments in next-generation occlusion devices
This 2021 study reviews the evolution of PFO closure devices and looks at potential advancements in technology and design for future procedures. It covers the benefits and limitations of next-generation devices.
Hämostyptika in antikoaguliertem Blut getestet
This German article provides a brief overview of how certain hemostyptics can stop bleeding in patients taking anticoagulants (blood thinners), which is particularly relevant for those undergoing surgery or post-surgical recovery.
In this 2023 video, viewers can watch an actual PFO closure procedure, providing a real-world look at the process and technology used during the surgery. This is an excellent resource for those considering the procedure, offering a behind-the-scenes look at what happens during a PFO closure.
