During fetal development, a small flap-like opening (the foramen ovale) is normally present in the wall between the upper left and right chambers of the heart (atria). The opening normally closes during infancy. A patent foramen ovale (PFO) refers to the opening of the flap when the foramen ovale does not close the way it should be, after birth. This may result in blood clot passing from right atrium to left atrium, resulting in stroke if the clots go to the brain. PFO can be closed by inserting a device through the blood vessels in the groin (percutaneous transcatheter approach).Most people with the condition never know they have it. A PFO is often discovered during tests for other problems.
Majority of patients with PFO do not experience any symptoms. Some patients may experience frequent headaches (migraine).
Although uncommon, a blood clot formed in venous system, such as the leg veins, can travel through the blood to the heart and, if the person has a PFO; the blood clot can cross into the left side of heart and go to the brain, resulting in a stroke. This condition is called paradoxical embolism.Patients with PFO are advised to avoid scuba diving in view of the risk of paradoxical embolism and decompression sickness.Patients who do not suffer from any symptoms may not need routine follow-up with serial echocardiograms.
PFO can be diagnosed through an echocardiogram (ultrasound imaging test of the heart). Sometimes, a “bubble test” may be required during an echocardiogram to confirm the presence of a PFO.
Some studies suggest that PFO may be present in as high as 27% of the population. It is diagnosed on transthoracic and transoesphageal echocardiography with demonstrable significant right to left shunting (evidence for blood going from right to left chambers).
There is usually no follow-up or treatment required if the patient does not suffer from any symptoms. In certain circumstances, however, the doctor may recommend a procedure to close the PFO.
PFO closure is a minimally invasive, catheter-based procedure that involves the use of a device called the "occluder”, to close the PFO.Studies have shown that patients with stroke (aged between 18 and 60 years old) who are treated with PFO closure, have lower risk of recurrent stroke. Possible procedure related complications, however, may include:Serious risks (less than 1%)
Other potential risks (less than 10%)
However, not all PFOs need to be closed. The PFO device was approved in 2016 by the US Food and Drug Administration (FDA) based on 10 year resuts of a randomized study which involved patients <60 years old with PFO and cryptogenic stroke (of unknown cause). It compared patients treated with PFO device plus blood thinning medications with patients treated with blood thinning medications alone and found a 50 percent reduction in new strokes in patients with PFO device. Other less common indications for closure include decompression illness in professional divers, cyanosis (mixing of deoxygenated [blue] blood in the left chambers causing breathlessness especially with certain posture.
The patient will need to fast at least four to six hours prior to the procedure and certain medications held off.
The patient usually stays in hospital overnight after the procedure for observation before discharging home the next day after chest X-ray and echocardiography.
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