Can a Closed ASD or PFO Reopen? Causes of Residual Leaks

Once an atrial septal defect (ASD) or patent foramen ovale (PFO) has been successfully closed, the hole itself does not “reopen.” When a device is placed to close the hole, your body’s natural healing process works to make the closure permanent. However, some patients do experience what doctors call a residual shunt, which is a small leak around the edges of the device rather than the hole tearing open again.

How the Closure Becomes Permanent

The permanence of your closure relies on a process called endothelialization ^[1]. After the closure device (often a mesh-like plug) is placed into the heart, your body begins to grow its own tissue over it. The most significant healing typically happens during the first 3 to 6 months. Over time, heart tissue covers the device, fully incorporating it into the wall separating the upper chambers of your heart (the septum). While doctors expect this coverage to be well underway within the first six months, research shows that complete tissue coverage can be a gradual process and is sometimes still incomplete during mid-term follow-ups ^[1][2]. During this healing phase, it is critical to ask your doctor about and follow guidelines on physical restrictions—such as avoiding heavy lifting or intense straining—to give the device time to settle securely. Once this tissue has grown over the device, it becomes a permanent part of your heart.

What is a Residual Shunt?

Rather than the hole reopening, it is more common for a device to leave a tiny gap where blood can still pass through. This is known as a residual shunt ^[3]. A residual shunt means the seal around the device is not 100% tight.

• How common is it? In the weeks immediately following the procedure, residual shunts are observed in approximately 25% of patients after PFO closure ^[3]. However, as your heart tissue grows over the device during the first 6 to 12 months, this rate typically drops significantly as the leak seals itself.
• When does it happen? These leaks are usually present immediately or shortly after the procedure. They do not mean a fully sealed hole has suddenly popped open again.
• Why does it happen? The unique shape of your heart can make a perfect seal challenging. For example, having a long PFO tunnel or an atrial septal aneurysm (a floppy, extra-flexible section of the heart wall) can make it harder for the device to lay completely flat, increasing the chance of a small leak ^[4][3].

Rare Complications and Warning Signs

In very rare instances, a closure device can shift out of place, a complication known as device migration ^[5]. If a device moves, it could theoretically leave the original hole exposed. However, this is extremely uncommon and typically happens soon after the procedure rather than years later ^[5].

• When to seek help: You do not need to wait for a scheduled scan if you feel unwell. If a device were to move or cause issues, you might experience warning signs like sudden chest pain, unexplained shortness of breath, or new heart palpitations ^[6][7]. If you experience these symptoms, you should seek emergency medical attention immediately.

Monitoring Your Closure

Because tissue growth takes time and residual shunts can occur, your care team will monitor you through regular follow-up appointments. Typically, imaging is performed soon after the procedure, with follow-ups commonly at 1 month, 6 months, and sometimes 1 year.

• Echocardiograms (Ultrasounds): Your doctor will likely order a specialized ultrasound to check the device position and look for leaks ^[8]. This often includes a bubble study—where agitated sterile saltwater is injected into your IV to create tiny, harmless bubbles. The doctor watches the ultrasound to see if any bubbles cross through a leak in the device ^[9].
• CT Scans: Cardiac computed tomography (CCTA) is another reliable imaging method used to check how well the device is sealed and whether tissue has grown over it properly ^[10].

Even if a small residual shunt is found, it does not necessarily mean the procedure failed. The primary goal of closing a PFO or ASD is to prevent major health events, such as a recurrent stroke, and a tiny residual leak may not always increase your risk for these events ^[11]. If a residual shunt is deemed significant, your doctor can often manage it with medication or, if necessary, successfully close it with a second specialized procedure ^[12].