December 26, 2022 Author : José Roquette What is it and what are the functions of the foramen ovale ? The foramen ovale , ostium secundum , or foramen Botalli is a hole in the interatrial septum (between the heart atria), which allows communication and blood flow between the right and the left atrium. It is normal in the fetus and has important functions in the fetal circulation that end with birth . During pregnancy, the fetus's oxygen needs are met by the mother; Oxygenated blood reaches the fetus through the placenta and the umbilical vein and most of it is directed towards the heart, where it enters in the right atrium; From there, it passes to the left atrium through the foramen ovale , goes to the left ventricle and enters the aorta artery and the great circulation; In addition to the foramen ovale , the ductus arteriosus and the ductus venosus are other structures that intervene in the fetal circulation and have no functions after birth. After birth, with breathing and expansion of the lungs, oxygenation of the blood is carried out in the lungs, and communication between the atria is no longer necessary or desirable. Thus, the foramen ovale ceases to function and in most cases it closes shortly after birth or during childhood . What is patent foramen ovale? For unknown reasons, in about 25% of people the foramen ovale fails to close . This situation is called patent f oramen ovale , or PFO , and allows blood to pass from the right atrium to the left and vice versa. Most people with patent foramen ovale don't have any symptoms , and may never even know that have it; PFO is often detected incidentally in an image exam performed for some other reason, often routinely. However, although rarely, patent foramen ovale can have complications : It can be the cause of low levels of oxygen in the blood, by maintaining the flow between the atria and not enough blood reaching the lungs to be oxygenated; It may be related to a stroke. How can the patent foramen ovale be the cause of a stroke? It is common that tiny blood clots are formed in the veins, and under normal circumstances do not cause any problems. After these clots enter the heart in the right atrium, they travel to the pulmonary circulation and are filtered in the small pulmonary capillaries, without having undesirable consequences. When there is a PFO, these tiny clots that arrive in the right atrium can pass to the left atrium and end up entering the systemic circulation and the arteries that supply the brain . Even with a size that would not be a problem in the lungs, in the brain these clots can block a vessel and cause an ischemic stroke. Therefore, when the causes that justify a stroke are not known, especially in people under 55 years old, usually an echocardiogram is ordered to find out if there is a patent foramen ovale . How is patent foramen ovale treated? The decision on the treatment of patent foramen ovale depends on the particularities of each case. Treatment may not aim to close the patent foramen ovale , but only to control clot formation through anticoagulant or platelet anti-aggregant medication. When there is an indication to close the patent foramen ovale , the procedure can be done by cardiac surgery or through a less invasive procedure called transcatheter repair . In this, a catheter is inserted into a vessel in the groin that is then directed to the heart where a device is applied that closes the foramen ovale . This device needs to have an anchorage point because, which is defined by the ultrasound. If it does not have one it becomes necessary to opt for a simple heart closure surgery. Meet the cardiac surgery clinical team from Hospital da Luz network. The content published in the Health Guide is intended for the general public and is provided for informational and educational purposes only. It does not replace individual medical assessment, diagnosis, or personalized clinical advice from a qualified healthcare professional. The content is produced or reviewed by physicians and other healthcare professionals at Hospital da Luz and is based on the knowledge available at the time of publication or the most recent update, as indicated at the beginning of each item.
