Saturday, 3 March 2012

Patent Foramen Ovale

A commonly asked question in the exam, a PFO is associated with a number of clinical conditions and may require closure. A review published in the British Journal of Cardiology provides a good overview of this, and can be found here.

The indications for closure of a PFO include the following:

1. Paradoxical embolisation - This is where a thrombus migrates from the right heart to the left, and then can lead to a stroke (cryptogenic stroke). Closure of the PFO is indicated, and patient may require warfarin.

2. Decompression sickness - Neurological symptoms in decompression sickness has been associated with PFO, and closure is indicated

3. Migraine with aura - There is no strongly established relationship between PFO and migraine with aura, as some studies have disproved this link. The exact etiology is unclear, and has been attributed to serotonin that bypasses metabolism due to the right to left shunt.

4. Platypnoea Orthodeoxia Syndrome (POS) - A rare condition characterised by breathlessness in upright position, relieved when supine. It is seen in patients with liver cirrhosis, aortic aneurysm and following a pneumonectomy. This condition has been associated with a PFO, and closure has shown to be of benefit.

For the MRCP exam

1. The relation between migraine and PFO must be remembered for the purpose of the exam. There may be a question on this. Keep in mind however the weak association.

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