PFO Closure: Challenges and Opportunities

Why have device manufacturers who have successfully introduced a number of Patent foramen ovale (PFO) closure devices in Europe, had difficulty conducting randomized trials to gain US market approval?

This article preview is reprinted from Medtech Insight - May 2008

Patent foramen ovale, or PFO, is a congenital cardiac defect that occurs when a flap-like opening in the septal wall between the right and left atrial heart chambers fails to fully close after birth. The opening serves an important purpose during fetal development, enabling oxygenated blood from the placenta to bypass the nonfunctioning lungs and enter directly into the fetal circulation. Following birth, it normally fuses shut to ensure that all of the blood returning from the tissues and entering the arterial circulation is first filtered through the lungs. However, in an estimated 25% of the population, this opening fails to close properly and may occasionally enable unfiltered blood to cross from the right to left atrium and into the arterial circulation. The biggest fear when this occurs is that embolic particles in the unfiltered blood will travel to the brain and cause a stroke.

But PFO and other abnormal right-to-left shunts (RLS) also have been linked with certain types of severe migraine headaches (ie, migraine with aura). These are believed to be triggered when emboli or some other unknown migraine-producing substances in the blood reach the brain.

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