The open or persistent foramen ovale is a congenital heart defect characterized by an opening in the wall (septum) that separates the upper spaces of the heart: the right and left atrium.
The atrial septum (septum interatriale) is the heart tissue that separates the two atria.
The ventricular septum (sectum interventriculare) is the wall that separates the two chambers of the heart.
The foramen ovale is a small hole in the interatrial cardiac septum.
The open foramen ovale affects blood circulation. If the hole is relatively large, it can cause various symptoms.
In the maternal uterus, the fetus does not use the lungs to oxygenate the blood, but depends on the maternal circulation via the fog cord.
The blood flows from the veins to the right side of the fetal heart, then flows through the foramen ovale to the left side of the heart, thus skipping the lungs of the child.
Usually, the foramen ovale closes at birth, when blood pressure increases in the left region of the heart and provokes the closure of the foramen.
If the atrial septum does not close correctly, this defect is called open or persistent foramen ovale.
This opening works like a valve that opens only under certain conditions, namely when there is a higher pressure inside the chest.
This increase in pressure exists when the person pushes, coughs or sneezes to defecation.
If the pressure is strong enough, the blood can flow from the right to the left atrium.
If a blood clot is located in the right side of the heart, it can enter the left atrium through the foramen ovale and travel from the heart to the brain (triggering a stroke) or clog a coronary artery (and trigger a heart attack).
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Types of atrial septal defect
The classification is based on the involvement of other cardiac structures and on the type of formation during the early development of the fetus.
There are three types of defect:
- The ostium secundum defect is the most common and is located in the middle of the atrial septum;
- The ostium primum defect is located in the lower part of the septum and is associated with an anomaly of the mitral valve (often a leak);
- The sinus venosus defect is located in the upper part of the septum and is characterized by a malformation of the right upper pulmonary vein.
Distribution of open foramen ovale
The prevalence of open foramen ovale is about 25% of the general population.
In patients with cryptogenic stroke, the presence of an open foramen ovale is about 46 percent.
This applies to patients who have had a stroke at the age of less than 55 years.
See American Heart Association and American Stroke Association (http://stroke.ahajournals.org/content/37/2/577.full) guidelines.
The causes are not clear, but a familial accumulation (genetically determined) is the most likely.
An open foramen ovale may be caused by an atrial septal aneurysm, which is characterized by excessive mobility of the atrial septum.
Symptoms of open forum ovale
Most patients have no symptoms.
Stroke and open foramen ovale:
The open foramen ovale is present in 46 percent of strokes.
The most common symptoms of stroke are:
- weakness or loss of sensitivity in the face, arm or leg on one side of the body;
- loss of vision or darkening (as if a curtain is falling) in one or both eyes;
- loss of speech, difficulty speaking or understanding what others are saying;
- sudden and severe headache for no apparent reason;
- Loss of balance and insecurity when walking.
Migraine headache and open foramen ovale:
Headache is more common in patients with an open foramen ovale.
It appears that closing the open foramen ovale reduces a migraine with aura, but more studies are needed to confirm this claim.
Usually, these problems do not appear until adulthood, usually after 30 years. Complications are rare in infants and children.
Diagnosis of open foramen ovale
An open foramen ovale can be detected by an echocardiogram.
In some cases, the patient needs to cough or perform the Valsalva maneuver to increase the pressure in the right atrium.
This can increase blood flow from the right to the left atrium.
Transesophageal echography can provide a more detailed insight into the heart abnormality.
Transcranial Doppler sonography shows the possible entry of microembolism into the cerebral circulation. This means that the lungs did not stop them and consequently they migrated from the right atrium to the left atrium.
Therapy of persistent foramen ovale (PFO)
Patients with a mild form of persistent foramen ovale do not need therapy if it is not associated with other ailments, such as stroke.
Patients who have suffered a stroke or transient ischemic attack (TIA) may take anticoagulants to thin the blood, for example, aspirin, Plavix (clopidogrel), or Coumadin (warfarin) in cerebral ischemia.
Those who take anticoagulants can travel by plane, but should not do diving under any circumstances.
Correction of foramen ovale persistens
It is not clear which treatment is better for this condition.
Scientific studies have shown that, first of all, there are advantages in preventive measures to prevent stroke in patients with an open foramen ovale.
A person with open foramen ovale who has already had a stroke has a greater risk of recurrence due to risk factors, such as the presence of another defect called atrial septal aneurysm.
Therapies in these patients continue to be researched and include:
- Anticoagulation (liquefying the blood) with aspirin, clopidogrel or warfarin
- Surgery to eliminate the defect
- percutaneous closure device
The long-term risks and benefits of the percutaneous closure device in the treatment of patients with open foramen ovale are not yet fully understood.
Non-surgical treatment: cardiac device
In some patients, a cardiologist and a neurologist may recommend occlusion of an open foramen ovale.
In most cases, percutaneous occlusion is preferred to surgery.
As part of the procedure, a cardiac catheterization is performed.
The catheter is inserted via an inguinal vein and advanced to the heart.
A balloon is inserted into the open foramen ovale to determine the size and position.
A pressure measurement is carried out in the atria.
You use a small catheter with an image converter in the heart to look at the inside.
If the cardiac catheter shows that the open foramen ovale is of an appropriate size and is located in a convenient place that can be closed with this device, the cardiologist uses this device to close the hole.
