What Is Patent Foramen Ovale?

Overview

A tiny flap or opening between the top right and left chambers (atria) of your heart is known as a patent foramen ovale (PFO). Before birth, everyone possesses this opening, known as a foramen ovale. This usually closes after delivery for most people. The condition known as patent foramen ovale is when the flap remains open after delivery. "Open" refers to "Patent".

To acquire blood that is rich in oxygen, a foetus does not use its lungs. Rather, this blood is acquired through the umbilical cord and the mother's placenta. The foetus's right upper chamber of the heart (right atrium) sends oxygen-rich blood to the left upper chamber (left atrium) through the foramen ovale. The blood then travels to the left side of the developing heart to supply oxygen to the brain of the foetus.^1,5

After birth, the foramen ovale usually closes. As soon as the infant begins to breathe, blood begins to flow to the lungs in order to take up oxygen. The left side of the baby's heart receives this blood, after which it is circulated to the remainder of their body.¹

Patent foramen ovale is part of a group called ‘’atrial septal defects (ASD)’’.  In 5%–10% of all congenital heart abnormalities, ASDs occur as an isolated abnormality, making them the third most prevalent kind of congenital heart disease. An ASD is a component of the cardiac defect in between 30% and 50% of infants with congenital heart abnormalities. The incidence appears to be rising as a result of enhanced echocardiography identification of silent abnormalities. The prevalence is greater in females with a  ratio of females to men of 2:1.^2,3

PFO patients typically don't have any symptoms and don't require medical attention. However, mini-stroke and stroke are two rare issues associated with PFO.

Anatomy and Physiology

Mechanisms of the heart

It may be useful to understand how the heart normally functions in order to have a better understanding of patent foramen ovale.

Four chambers make up the normal heart's blood-pumping⁴ system:

• The right atrium, or upper chamber, is located on the right side. The body pumps blood with low oxygen content into this heart chamber. Through the tricuspid valve, blood is pumped to the lower right chamber of the heart
• The right ventricle, or the right lower chamber. Through a sizable blood vessel known as the pulmonary artery, this heart chamber delivers blood to the lungs. The blood takes up oxygen in the lungs. The pulmonary valve allows blood to pass through. When the chamber relaxes in between beats, the valve shuts
• The left atrium, or the left upper chamber. The oxygen-rich blood from the lungs enters this chamber of the heart. Blood is sent into the left lower chamber from here, with the help of the mitral valve, the pulmonary veins, and other structures
• The left ventricle, or left lower chamber, is colloquially just called ‘’the ventricle’’. The heart's primary pumping chamber is this one. The blood flows from here to the aorta, the body's main blood conduit, which transfers the oxygen-rich blood to the rest of the body. The aortic valve allows blood to flow through it and shuts as the chamber relaxes.

The heart before delivery

The lungs of an unborn child are still developing, and they are not breathing. Thus, there is no requirement to circulate blood to the lungs. Blood circulation bypasses the baby's lungs at this point. It transfers oxygen-rich blood from the mother to the baby's body through the placenta and umbilical cord.

Blood vessels in the baby's body attach to the umbilical cord. The vein that carries blood from the body to the right upper chamber of the heart, i.e. the route via which oxygen-rich blood enters the heart,’ is called the inferior vena cava. After that, the blood enters the left upper chamber of the heart by passing via the foramen ovale. The blood finally reaches the left lower chamber of the heart, which distributes it throughout the body.⁶

An infant's heart

A baby's heart's blood flow varies as their lungs start to function. The blood that is rich in oxygen is now leaving the lungs and entering the left upper chamber of the heart.

The foramen ovale flap opening typically closes under the force of the blood pouring through the heart. The hole closes at some point during infancy in most persons.⁶

Causes and risk factors

Patent foramen ovale are irregular and unclear in their cause. The most likely association is that there is a genetic link and thus inheritance of certain genes may play a major role.

A tiny quantity of blood can pass between the flaps that join your left and right atrium thanks to a patent foramen ovale. Normally, blood cannot pass through these flaps.

A patent foramen ovale often doesn't pose any issues. However, PFO might allow a blood clot to move from your heart's right to left side. The clot might enter your body through your heart. Your brain might lose blood flow if the clot gets there. This would result in cerebral ischemia. Your heart and kidneys, among other organs, might be harmed by the clot.^1,5,8

Symptoms and presentation

For this condition, the majority of those who have the illness are unaware of it. Testing for various medical conditions frequently reveals the presence of a patent foramen ovale.

The majority of newborns and children with ASD seem healthy and pink. Typically there are auscultatory findings, this is when doctors listen to your chest using a stethoscope. They can hear a murmur and, if the hole is large enough, they can also hear a rumbling sound.

However, the auscultatory findings can vary sometimes, if the shunt is too small, there are no classic auscultatory symptoms as previously mentioned. If the right ventricle is not functioning well, the results might not be present in a lot of babies and children, even those who have a significant abnormality. Adults with big shunts are far more likely to have classic auscultatory findings.¹

Diagnosis

How is patent foramen ovale diagnosed?

First, your medical professional will examine you physically and inquire about your problems. Your provider may suggest the following tests⁷ if they think you have PFO:

• Transthoracic echocardiography: An echocardiogram, often known as an echo, utilises sound waves to produce pictures of the chambers of your heart. A transthoracic echocardiography is performed by a healthcare professional on your chest using a handheld device that looks like a computer mouse.
• Transesophageal echocardiography (TEE): During this procedure, your doctor inserts a small camera-equipped probe into your oesophagus. Compared to normal echocardiography, a TEE can provide a crisper image of PFO, however this is an invasive procedure and is only done when the other ultrasound doesn't show much.
• Transcranial Doppler (TCD) ultrasound: TCD ultrasound examines blood flow to and from your brain using sound waves. This test can also detect thrombotic strokes.

Treatment options

The majority of patients with patent foramen ovale won't require care. If you have a history of strokes or blood clots, however, your doctor could advise therapy. PFC treatments^1,9 consist of: 

• Medications like warfarin or aspirin that prevent blood clots 
• Catheterization: a long, thin tube called a catheter is used by your interventional cardiologist to seal the flap. The catheter is advanced via the artery to your heart by your surgeon after it is inserted into the big vein in your groin. After that, they shut the flap using a closure device. According to studies, if you're under 60, catheterization is a better option for treating PFO than surgery.
• In the event that catheterization fails, they could recommend surgery. Your surgeon will make an incision and sew the flap closed during heart surgery

According to recent studies, PFO closure may help patients who have experienced an unexplained stroke, from having another one in the future. Consult your healthcare practitioner to determine the best course of action for you.

Complications and associated conditions

• Typical side effects of anticoagulant and antiplatelet medications include intracranial haemorrhage and bleeding 
• Device embolisation, stroke, air embolism, and perforation leading to tamponade are examples of intraprocedural problems with device closure. Nevertheless, with rates of less than 1%, they are all uncommon occurrences in skilled hands  
• Arrhythmias are rare and only happen in 3%–5% of cases. While atrial fibrillation, a particular kind of arrhythmia, can occur in5% to 6% of cases with some devices, it is typically linked to the production of blood clots. Individuals who had closure done had a higher incidence of atrial fibrillation than those receiving anticoagulation^1,8,
• Late cardiac perforation (damage occurring after device insertion) has been documented, uncommonly, with certain devices 

Prognosis and outcomes

PFO has a great prognosis in newborns and children, and in the majority of them, PFO closes with no intervention. The prognosis is good for children and adults with thromboembolism risks who need surgical closure. The results of surgeries are well-established, and percutaneous closure (a procedure using the blood vessels to access and repair the defect) shows promise. However, there have been reports of dislodgement, embolism, and failure to seal the PFO. In addition, there is a chance that the percutaneous technique will cause vascular injury, stroke, thrombus development, and infective endocarditis.¹

FAQs

Can patent foramen ovale close on its own?

PFO is a typical aspect of a foetus's circulation. However, this little hole in most newborns normally heals very quickly after birth. However, this doesn't always happen. In youngsters it's a common discovery, but not in adults. If it causes problems, it needs to be closed.

What are the symptoms of a patent foramen ovale?

Usually there are no symptoms. A PFO is usually found when investigating other heart conditions. But other heart conditions can be associated with PFO,and thus the signs and symptoms of those conditions can be relayed as ones belonging to PFO.

Is it safe to exercise with a patent foramen ovale?

Usually it doesn't cause any problems with moderate exercise, however, there have been studies that have recorded a drop in blood oxygen levels during exercise, and it would be wise to exercise cautiously because of this.

How is a patent foramen ovale treated, and can it be cured?

It doesn't usually need treatment, but if one has symptoms, it may be treated by closure of the foramen ovale, either minimally invasively or via surgery.

Summary

The tiny opening known as the patent foramen ovale (PFO) connects the left and upper chambers of your heart. PFO frequently has no symptoms and doesn't need to be treated. However, it can occasionally cause a stroke or mini-stroke. Your healthcare professional may recommend therapy if you have a history of blood clots or strokes. Medication, catheterization, and surgery are all forms of treatment. People who are affected with patent foramen ovale typically live long lives.

Keep in mind these red flags, in case of stroke.If you experience any of the following symptoms, get in touch with your doctor right away or dial your local emergency number:

• difficulty comprehending or speaking
• lightheadedness or unsteadiness
• Your face, arm, or leg may feel numb or weak
• difficulty seeing with one or both eyes
• severe headache that struck suddenly