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Patent Foramen Ovale

Patent Foramen Ovale: Risk Factors, Diagnosis, Treatments, Post-surgery care | National Heart Centre Singapore

Patent Foramen Ovale - What it is

The Foramen Ovale is a flap like opening in the upper heart chambers (atria) which allows communication (eg. blood/blood clots (emboli)/air bubbles) to flow between the atria. It is present in all fetuses and closes shortly after birth. If it does not close, it is called Patent Foramen Ovale (PFO) through which blood clot can pass 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).

Patent Foramen Ovale - Symptoms

Patent Foramen Ovale - How to prevent?

Patent Foramen Ovale - Causes and Risk Factors

Risk Factors

The procedure usually takes between one to two hours and the success rate is about 95%. However, there are known risks involved. The risks and their estimated incidence of occurrence are: 

  • Device dislodgement (embolization) and the need for emergency heart surgery – <1%
  • Device erosions (device erodes through the heart walls) – 0.3%
  • Death – <1% (usually from perforation of the heart chamber).
  • Dislodgement of clot or air bubbles to the brain (causing stroke) and other organs – 1%
  • Rhythm disturbance (arrhythmia) are usually transient – 1-2%
  • Other potential risks – Allergic dye reaction, anaesthetic reaction, bleeding and bruising around the sheaths in the groin, injury to the artery/vein/nerves in the groin, perforation of the oesophagus (from the Transoesophageal Echocardiography (TEE) probe), headache or migraine and infection, allergic reaction to the nickel component of the device 


Some of these complications, if they occur, are of a serious nature and may require further treatment including surgery and prolonged hospitalisation. In the event of device dislodgement, you may require surgery for removal of the device and closure of the PFO at the same time. 

Patent Foramen Ovale - Diagnosis

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).

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.

Patent Foramen Ovale - Treatments

This procedure is performed in the cardiac catheterisation lab. You will be given an anaesthetic which may be general (GA) or local (LA) depending on the technique used. In most cases, this procedure is performed under general anaesthetic (GA) which is given by a qualified anaesthetist. Once anaesthetised, an imaging probe (TEE) will be passed into your gullet (oesophagus) for accurate assessment of the PFO and to assist during deployment of the device. You will lie on an X-ray table and an X-ray camera will move over your chest during the procedure. A plastic catheter (a long tube) will be inserted via a vein in the groin and navigated until it reaches the heart. Sometimes (depending on individual case), the catheter is position at different chambers of your heart to measure the pressure and oxygen content prior to device closure. In certain circumstances, balloon sizing of the PFO may be required. Once your doctor is satisfied with all the measurements, the appropriate size device is connected onto a cable, put into a special delivery tube, advanced through your PFO and carefully deployed. Your doctor will study the device’s position and stability before releasing the device. The catheter and imaging probe are removed and the procedure is completed.

Patent Foramen Ovale - Preparing for surgery

​The patient will need to fast at least four to six hours prior to the procedure and certain medications held off.

Patent Foramen Ovale - Post-surgery care

​The patient usually stays in hospital overnight after the procedure for observation before discharging home the next day after chest X-ray and echocardiography

Patent Foramen Ovale - Other Information

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