How is a PFO treated? Treatment is a catheter procedure or surgery to close the opening in the heart.The foramen ovale is a hole in the wall between the left and right atria of every human fetus. This hole allows blood to bypass the fetal lungs. PFO treatment closes the Patent Foramen Ovale (PFO) through blood thinning medicines or a catheter-based procedure to close the hole. However, it may cause serious complications under certain circumstances. In roughly 75 percent of cases, the hole, called a patent foramen ovale (PFO), closes on its own and requires no treatment. A PFO closure is a procedure that can help lower the risk of a stroke for some people. A patent foramen ovale (PFO) is a hole in the wall between the heart's two upper chambers (atria). Before birth all babies have this opening.