Patent Foramen Ovale and Migraine
The foramen ovale is a channel between the atria of the foetal heart allowing blood to flow from the right to the left atrium, which shunts oxygenated blood to the systemic circulation during foetal development. It is not needed in adult life when the lungs are functional, and closes after birth. Or at least it closes most of the time, because defects in the septa between the atria are relatively common, and a significant minority of adults have a patent (open) foramen ovale.
Patent foramen ovale (PFO) is associated with increased risk of stroke. In recent years it has also been associated with migraine. While closing a large PFO to try and prevent stroke might make sense, cardiac surgery to prevent migraine, however bad, is difficult to justify.
This short article examines some of the literature on PFO incidence, and takes a quick look at the current evidence on PFO closure and the effects on migraine.
There are two main methods. One is to look at the heart directly, usually after death. When patients are alive, the main method is transoesophageal echocardiography (TOE). The first question is whether these two methods give the same answer, and whether they are diagnostically equivalent. The answer [1] is that they are.
Briefly, 35 consecutive patients with prior TOE who died underwent a post mortem examination of the heart. Post mortem PFO was found in 9/35, and TOE picked up the same nine. Moreover, both methods gave the same PFO diameter (Figure 1). We might expect case series using either method to give the same result, therefore.
