Right-To-Left Shunt and Migraine

Abstract

Right-to-left shunt (RLS) is an abnormal pathway between the venous and arterial circulations, and includes both intracardiac and extracardiac RLSs. Intracardiac RLSs are usually related to patent foramen ovale (PFO). Contrast-enhanced transcranial Doppler ultrasonography (c-TCD) is a clinically applicable and reproducible method of detecting RLSs. Migraine is a common disabling neurovascular disorder. It has a high prevalence, 7.9%-14% in the western population and 9.3% in the Chinese population. The pathogenesis of migraine is not well understood. Available data suggest that PFO is more common in patients with migraine, whereas other studies have reported that the prevalence of RLS is similar in patients with and without migraine. The aim of the present study was to assess the prevalence and extent of RLS using c-TCD in Chinese patients with migraine and compare them to the prevalence and extent of RLS in healthy controls. We then used these data to evaluate the relationship between RLS and migraine. The main finding was that the prevalence of RLS was significantly higher in Chinese migraineurs than it was in healthy controls. Hence, there appears to be a close relationship between RLS and migraine without aura as well as between RLS and migraine with aura. In addition, the proportion of large shunts was significantly larger in migraineurs with and without aura than it was in healthy controls. It suggested that RLS, especially large RLS, is associated with migraine with aura as well as migraine without aura. RLS may be involved in the pathogenesis of migraine. Detection of right-to-left shunt should be considered in patients with migraine.