The link between migraine and PFO is . . .
- Incidental & man-made
- Almost certain
- A wild imagination
Answer : One of the above is correct , but we do not know which one is !
There has been many patients with TIAs , cryptogenic strokes , who had documented PFO ,complain of prolonged head aches . This was the beginning of suspicion of PFO as a cause for migraine .Then the device industry foresaw a huge opportunity . Things began to unfold and the concept is currently as nebulous as it can be .
Mechanism of migraine in PFO
(All are presumptions )
- Right to left shunting of vasoactive amines from venous circulation (Serrotonin) which bye- passes the lung where they are supposed to get filtered.
- Venous micro emboli (Antiplatelet agents reduce migraine as well as TIA ! )
- Hypoxia transient – cerebro vascular hypersensitivity
- Atrial naturetic peptide spills more into systemic circulation through PFO
- If right to left shunting is causing the migraine , why it is not fully disappearing even after closure of PFO (MIST data with starflex device , migraine persisted in a significant chunk !)
- What is the incidence of migraine in the prototype right to left to shunt situations like TOF, Eisenmenger , pulmonary AV fistula ? if shunting is the mechanism , logically migraine incidence should be very high in this population , but it is not .
- Migraine occurs in 10 % of population, PFO is present in 20% . What are the chances of over lap ? It could be the simple statistics at play !
Where is the evidence ? The mystery called MIST study.
This study , done in UK generated more controversy , which it was supposed to remove . Still this study is considered to be a major evidence for the link between PFO and migraine . Star flex device was promoted by NMT medical Boston .
The link between migraine and PFO can be a fact or myth depending upon our belief in current methods of research in science. The issue is debatable . Of course , one issue is probably closed forever , even if they are linked casually (or seriously ) device closure can never be a sensible treatment option for migraine ! *
We expect a proof / disproof in this mysterious migraine -PFO hypothesis very shortly. Of course , many cardiologists already have their own conclusions !
*Please note , PFO device closure for stroke in young is a different story