Options for the secondary prevention of stroke in patients younger than 60 years who have had a cryptogenic ischaemic stroke thought to be secondary to patent foramen ovale (PFO) include PFO closure (with antiplatelet therapy), antiplatelet therapy alone, or anticoagulants. International guidance and practice differ on which option is preferable. The BMJ Rapid Recommendations panel used a linked systematic review(1) triggered by three large randomised trials published in September 2017 that suggested PFO closure might reduce the risk of ischaemic stroke more than alternatives.(2-4) The panel felt that the studies, when considered in the context of the full body of evidence, might change current clinical practice. 5 The linked systematic rev...