Introduction

The Foramen Ovale is a small 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 paradoxical embolism and 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).

How is the procedure performed

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.

Is the procedure safe

The procedure usually takes between 1 to 2 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 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. As PFO device is relatively new, long term follow-up data are not available and there may be other risks which are not known at this time.

Who is it for

Some studies suggest that PFO may be present in as high as 27% of the population. However, not all PFOs need to be closed. PFOs which are associated with cryptogenic stroke (stroke of no identifiable cause) in young patients < 40 years old who has failed medical therapy or not keen to take medication for life with demonstrable significant right to left shunting (evidence for blood going from right to left chambers) seen on echo scan device closure may be considered for closure. 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 (platypnoe orthodeoxia), etc