Does PFO Close by Adulthood?
No, a patent foramen ovale (PFO) does not reliably close by adulthood—it persists in approximately 25% of the adult population throughout life as a remnant of fetal circulation. 1, 2, 3
Natural History and Prevalence
The foramen ovale normally closes shortly after birth due to shifting pressures in the atrial chambers when the lungs begin functioning and pulmonary vascular resistance drops. 4
However, in approximately 25% of cases, the foramen ovale remains patent into adulthood, making PFO the most common congenital heart abnormality of fetal origin. 2, 3, 5
Some autopsy studies suggest PFO prevalence may decline with age, though it clearly persists in a substantial portion of the adult population. 1
Population-based echocardiographic studies confirm persistent PFO in adults:
Clinical Implications
PFO that persists into adulthood represents a potential anatomic substrate for paradoxical embolization, where venous thrombi can bypass pulmonary filtration and reach the cerebral circulation. 2, 3
The presence of PFO is particularly significant in younger adults with cryptogenic stroke, with 45.9% of young cryptogenic stroke patients having a PFO compared to 14.3% of young patients with stroke of known cause (odds ratio 4.70). 2
In older adults (≥55 years), the association between PFO and cryptogenic stroke is weaker but still present, with 28.3% of older cryptogenic stroke patients having a PFO versus 11.9% of older patients with stroke of known cause (odds ratio 2.92). 2
Key Clinical Pitfall
Do not assume that PFO will spontaneously close in adults—once a patient reaches adulthood with a persistent PFO, it is unlikely to close spontaneously and should be considered a permanent anatomic variant. 4, 6 The critical period for physiologic closure is immediately after birth, not during adult life.