The foramen ovale is a communication in the heart that connects left and right atrium during the embryonic period. The foramen ovale usually closes in the first year of life, but in some people it remains open. It is the most common congenital cardiac anomaly in adults, with about 20-30% of the population having incomplete closure of the foramen.
Most patients with patent foramen ovale are completely asymptomatic, and the detection of this anomaly can be occasional.
One of the symptoms that may suggest the presence of a patent foramen ovale is migraine. For many years it has been observed that the presence of a patent foramen ovale was more frequent in patients with migraine, with an incidence varying between 15% and 66%. It was also shown that patients with patent foramen ovale had migraines more frequently than the general population.
On the other hand, migraine, one of the most common primary headache conditions, appears to affect approximately one billion people worldwide. According to a 2016 World Health Organization survey, it is the second leading cause of disability.
It usually presents with recurrent attacks of headache, with a duration that can vary from a few hours to few days. Its pathogenesis has not yet been fully elucidated, but it appears to involve the trigeminal nerve and its endings on the intracranial vessels.
In selected patients, closure of the foramen ovale is indicated. This is obtained with two main methods: with a classic surgery or with the placement, through a venous catheter, of a device that occludes the communication. The latter method has become the first choice for many patients with patent foramen ovale, thanks to its safety and efficacy.
One of the emerging indications for transcatheter closure of the foramen ovale is migraine. In this sense, different non-randomized studies have already shown an improvement in symptoms after closure of the defect.
On the other hand, the randomized clinical trials carried out so far have not demonstrated their efficacy endpoint, even though there have been some reductions in symptoms.
For this reason, to date, the closure of the foramen ovale does not represent a routine indication in migraine.
A new research, recently published in the Journal of the American College of Cardiology, presented an aggregate analysis of the results obtained in two randomized trials, showing that foramen ovale closure is a safe procedure and can significantly reduce the number of migraine attacks.
Both studies used an Amplatzer device for defect closure and evaluated the procedure’s efficacy and safety as a therapy for episodic migraine with or without aura.
The two studies were the PRIMA and the PREMIUM.
The efficacy endpoints were the mean reduction in monthly migraine days, treatment response rate, mean reduction in monthly migraine attacks, and the percentage of patients with a complete cessation of migraine.
The two studies also assessed the safety of the procedure and device-related adverse events.
In this analysis the data of 337 subjects were evaluated, 176 of whom underwent closure of the defect and 161 were initially treated with medical therapy only.
After one year of follow-up, comparing the two groups of patients, the analysis showed as patients that underwent closure had a reduction in average monthly migraine days, an average reduction in monthly migraine attacks and a greater number of subjects experiencing complete cessation of migraine.
Regarding safety, there were nine adverse events related to the catheter procedure and four adverse events related to the device. However, all these events were transient.
This pooled analysis of data from two major clinical studies appears to demonstrate that transcatheter closure of the foramen ovale is a safe procedure that can reduce migraine attacks, highlighting a complete remission of the symptoms in 9% of the treated subjects.
However, it should also be noted that in the evaluation of a symptom such as migraine a randomized and controlled, double-blind design is essential to obtain reliable results.
Both studies considered in the analysis followed a randomization procedure, but only the PREMIUM study had a double-blind design with a sham procedure.
Furthermore, the authors admit that patent foramen ovale is quite common in the general population, and that the studies may have included patients in whom these anomalies are “innocent bystanders” rather than the culprit trigger of migraines.
The results obtained in this analysis can therefore bring additional information to evaluate the usefulness of the procedures for closing the foramen ovale, but it seems far away the day when the guidelines will recommend this treatment in subjects with migraine.
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