THE ESSENTIAL
- The foramen ovale is a space located between the two atria of the heart. Its presence is perfectly natural in the fetus, but normally following birth, this hole is completely blocked by a membrane.
- This cardiac anomaly can lead to abnormal blood exchange between the cardiac atria, which can lead in the worst case to a cerebrovascular accident (CVA).
- In some patients, the cardiologist will choose to do percutaneous closure of the oval foramen, a procedure that can lead to atrial fibrillation for the first few weeks.
There are pathologies that we think we know well and we realize when we work on them that they are not as they appear to be. And it seems to be the case with the patent foramen ovale. Can you remind us what it is, what is its risk and what is its real frequency?
The foramen ovale refers to the structure that separates the left atrium from the right ear from the heart. But this structure is not something fixed or solid. In fact, these are two flexible walls which are joined to each other and in certain circumstances, these two walls may not be strictly joined, which creates a kind of cavity between them which allows a theoretical passage between the left ear and the right atrium.
Permeable foramen ovale: 1/4 of the population would have this heart defect
It is a heart defect which is extremely frequent since certain studies say that it would be there up to a quarter of the population. This can unfortunately sometimes be complicated because this passage between the left cavities and the right cavities can allow blood clots to pass which can come from the venous sector (therefore from the right sector to go into the left network), which can sometimes cause vascular accidents. cerebral.
Fortunately, it’s very rare, it doesn’t affect the 25% of patients with an open foramen ovale because some forms are more or less severe than others. But when it happens, you have to treat this patent foramen ovale by closing it. This is a procedure that can be done at Pitié-Salpêtrière: prostheses are placed percutaneously in order to permanently close this permeable foramen ovale. It’s not heart surgery, it’s a fairly simple procedure that lasts regarding half an hour. Patients may or may not be asleep as it can be done under light sedation. And so it allows with this prosthesis, to permanently close this permeable foramen ovale.
What is the relationship between foramen ovale closure and atrial fibrillation?
What we were able to demonstrate at the Pitié-Salpêtrière is that the fact of closing this permeable oval foramen by these prostheses can trigger cardiac arrhythmias, mainly atrial fibrillation. So it was known, we knew that it might trigger atrial fibrillation, but the rates that were conventionally reported in the literature were quite low. It was around 3 to 7% of patients following surgery, so relatively low.
At Pitié-Salpêtrière, we have a slightly more innovative approach by systematically using screening, monitoring and heart rate monitoring methods in the weeks following the operation. Concretely, following the skin closure procedure of the patent foramen ovale, our patients are discharged either with a portable device that monitors the heart rate for 28 days, or with a subcutaneous device that can monitor the heart rate for up to three years.
Thanks to this fairly generalist approach in all patients, arrhythmia rates were highlighted which were 3 to 5 times higher than what was classically described and which, in this case, was 21% within 28 days. . So I want to reassure the patients who have to benefit from this kind of intervention at Pitié-Salpêtrière, it’s not that serious, it’s completely manageable with medication. But it is something that we are happy to know and to be able to diagnose.
Atrial fibrillation: “we generally put in place an anticoagulant treatment”
Does this mean that you put in place anticoagulant treatments in follow-up procedures to close the foramen ovale?
So, if we detect a cardiac arrhythmia thanks to our approach, we generally put in place an anticoagulant treatment. So it’s a bit on a case-by-case basis. We try to make it as short as possible so that it is the least inconvenient for the patients. Generally, it lasts a few months and we set up, if it is symptomatic, an antiarrhythmic treatment for a few weeks. It is in fact believed that the cardiac arrhythmia which occurs following this prosthesis closure is linked to a phenomenon of irritation following the placement of the prosthesis. But with the passing weeks, the heart heals and therefore the phenomenon ends up disappearing in almost all cases following a few months. So the message is that it’s not a serious complication that would justify not doing this surgery. But it is an element that must be diagnosed in order to be able to better treat the patient during the survival period.
The stage following now is a research project that we were able to launch with Action-Coeur where we try to immediately treat patients who benefit from this type of intervention with an anti-arrhythmic treatment. The idea is no longer to be a spectator, to wait for the problem to occur to treat it, but to try to be proactive and prevent the complication with a transient anti-arrhythmic treatment.
