Algorithm for consideration of PFO closure in secondary stroke prevention based on the 2020 Practice Advisory Update Summary from the American Academy of Neurology.²²  *Shunt descriptor refers to degree of right-to-left shunting, not anatomic size. ^Includes hypertension, diabetes, hyperlipidemia, or smoking. °Single, small (<15 mm), subcortical, in the distribution of single penetrating artery.