What Is Patent Foramen Ovale?
A patent foramen ovale (PFO) is a small opening between the upper chambers of the heart that usually closes after birth. In about 25% of adults, this opening remains open. While most people with a PFO never experience any symptoms, it can become a hidden risk factor for stroke, especially in younger adults.
Why Is PFO Linked to Stroke?
When a PFO is present, blood clots from the veins can sometimes pass through the opening and travel to the brain, causing a stroke. This is called a paradoxical embolism. In young and middle-aged patients, PFO is a common cause of cryptogenic stroke—stroke with no clear cause found after standard testing.
Who Is Most at Risk?
- Patients under 60 years old with a cryptogenic stroke and no other stroke risk factors.
- Those with a high-risk PFO anatomy, such as a large shunt or aneurysmal atrial septum.
- Individuals with a history of multiple unexplained strokes or transient ischemic attacks (TIAs).
How Is PFO Closure Used for Stroke Prevention?
Percutaneous PFO closure is a minimally invasive procedure where a device is placed in the heart to close the opening. Clinical trials show that in well-selected patients, PFO closure can reduce the risk of recurrent stroke by about 3.4% over five years compared to medical therapy alone.
What Are the Risks of PFO Closure?
- The procedure has a periprocedural complication rate of about 3.9%.
- PFO closure is associated with a higher risk of developing atrial fibrillation, with an absolute increase of about 0.33% per year.
- The risk of atrial fibrillation is higher in patients with certain PFO anatomical features or older age.
How Do Doctors Decide Who Should Have PFO Closure?
Doctors use clinical scoring systems, such as the RoPE score and the PASCAL classification, to estimate the likelihood that a stroke was caused by a PFO. These tools help identify patients who are most likely to benefit from closure and avoid unnecessary procedures in those at higher risk for complications.
What Does the Evidence Show?
Meta-analyses of randomized controlled trials show that PFO closure reduces the absolute rate of recurrent stroke by about 0.67 strokes per 100 patient-years. The number needed to treat to prevent one stroke over five years is about 32. However, the benefit is mainly seen in younger patients with cryptogenic stroke and no other risk factors.
What Should Patients Know?
- PFO is common but not always dangerous.
- Not all patients with a PFO and stroke need closure.
- The decision to close a PFO should be based on individual risk factors and a thorough discussion with a healthcare provider.
“PFO closure can be a life-changing intervention for the right patient, but it’s not a one-size-fits-all solution. Careful patient selection is key to maximizing benefit and minimizing risk.”