Doctor Nguyen Tuan Long, from the cardiology department of Tam Anh General Hospital in Hanoi, explained that a 3.5 mm patent foramen ovale (PFO) was the cause of Mien's stroke due to a paradoxical embolism. Typically, small blood clots that form in veins, especially in the lower extremities, travel to the right side of the heart and are then pumped to the lungs where they dissolve harmlessly. However, in individuals with a PFO, sudden increases in right heart pressure due to coughing, sneezing, or straining can force these clots through the opening and into the left side of the heart. From there, they can travel to the brain, causing a stroke.

Without closure of the PFO, Mien faced a risk of recurrent strokes. After a minimally invasive procedure to close the defect, she recovered quickly, with stable blood pressure, and was discharged after two days.

The medical team performs the PFO closure procedure to prevent recurrent strokes. Photo: *Tam Anh General Hospital*

According to Dr. Long, PFO is a common congenital abnormality. During fetal development, the lungs are not yet functional, so blood bypasses them by flowing directly from the right atrium to the left atrium through a natural opening called the foramen ovale. After birth, when the lungs begin to function, changes in heart pressure usually cause this opening to close within the first few weeks or months of life.

In most cases, a PFO is asymptomatic and harmless. However, in some instances, it can lead to complications such as reduced blood oxygen levels causing shortness of breath, migraines, brain embolism, or stroke. The risk of complications depends on the size of the opening, the amount of blood flowing through it, and other risk factors.

According to the US National Institutes of Health (NIH), PFO is a major contributing factor in about 50% of cryptogenic strokes (strokes of unknown cause) in younger individuals.

Dr. Long recommends that patients under 60 who have experienced a stroke or transient ischemic attack (TIA), without typical cardiovascular risk factors, should be screened for PFO. Early detection and treatment can prevent serious health consequences. The minimally invasive PFO closure procedure can reduce the risk of recurrent stroke by up to 90%.

If warning signs of recurrent stroke occur, such as chest pain, shortness of breath, heart palpitations, severe headaches, movement and speech disorders, unusual bleeding or bruising, patients should seek immediate medical attention. A healthy diet, low in salt, fat, and organ meats, with plenty of fruits, vegetables, and about 1.5 liters of water daily, is also recommended.

*The patient's name has been changed.

Ly Nguyen