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Dr Diana R Holdright

Consultant Cardiologist

Dr Diana Holdright

Treatments - PFO / ASD Closure

In adults the two common types of hole in the heart that may require closure are the patent foramen ovale (PFO) and atrial septal defect (ASD), which are both congenital, i.e. present from birth.

A PFO is a hole or communication between the right and left sides of the heart, in a structure known as the interatrial septum, which normally separates the left and right atria, the collecting chambers at the top of the heart. It is present, and indeed essential, in the developing foetus but after birth has no useful function and closes naturally in approximately 75% of individuals. In the remainder, where it remains open (patent), it causes no problems whatsoever except in a tiny minority of individuals; some strokes, for example, are thought to come from small clots returning from the body to the right side of the heart and, instead of passing to the lungs, which act like a giant tea strainer, they can pass across the PFO to the left side of the heart and directly to the arterial circulation, and then to the brain. Similarly, diving to depth causes inert gases such as nitrogen or helium to accumulate within blood and tissues which, upon ascent, particularly if rapid or associated with deep dives, form gas bubbles in the veins, passing to the right side of the heart; if they cross a PFO they can cause neurological symptoms known as decompression sickness. Lastly, but of contentious nature, the aura of a migraine has been linked to the passage of certain chemicals across a PFO to the brain, bypassing the lungs which would normally inactivate them. Percutaneous closure of a PFO is a therapeutic option in appropriately selected patients, although there remains considerable debate regarding patient selection and effectiveness.

An atrial septal defect (ASD) is a larger communication between the right and left atria, causing blood to pass from the left to the right side of the heart and back again through the lungs, increasing the workload on the heart with every beat. There are various types of ASD, depending on their precise location, the most common being a secundum ASD. A secundum ASD may not be detected until adult life since the clues from examination are subtle in the early years. Symptoms usually develop when a patient reaches the age of 40 years or more, as a consequence of the inefficient shuttling of blood from left to right, and include fatigue, breathlessness and palpitations. These days most ASDs are closed percutaneously, avoiding the need for open heart surgery.

The techniques for PFO and ASD closure are almost the same; the procedure is performed in a catheter lab using X-rays and echo ultrasound guidance, and usually a general anaesthetic is required. A fine tube, a catheter, is passed from the blood vessel at the top of the leg to the heart, where it is guided across the PFO or ASD. A device, of which there are now many types, is carefully positioned to straddle the hole, and it is then deployed across the PFO/ASD. This will immediately diminish the potential for blood to shunt across the hole, and over time the body forms a thin lining over the device, reducing the shunt even further and generally sealing it completely. The patient should expect to go home either the evening of the procedure or the following day and is usually prescribed aspirin and similar drugs for a few months afterwards. Patients can lead an entirely normal life after the procedure but should have intermittent review for life to check that all remains well.

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Related page:

News - April 2012 - PFO closure in patients with stroke of unknown cause 

Treatments - PFO / ASD Closure