Mona Al Banna, MB BCh, Msc(Res)
Messé SR, Erus G, Bilello M, Davatzikos C, Andersen G, Iversen HK, Roine RO, Sjöstrand C, Rhodes JF, Søndergaard L, Kasner SE, and on behalf of the Gore REDUCE Study Investigators. Patent Foramen Ovale Closure Decreases the Incidence but Not the Size of New Brain Infarction on Magnetic Resonance Imaging: An Analysis of the REDUCE Trial. Stroke. 2021;52:3419–3426.
Patent foramen ovale (PFO) is found in one quarter of the population. However, in cryptogenic strokes, PFOs have been found in approximately one half of patients. (1) The association is even stronger in younger patients with a stroke, as a four-fold greater incidence of PFO has been detected compared to a stroke-free age- and sex-matched control group. (2) The pathophysiology of PFO-related stroke involves the paradoxical embolism of a clot from the venous circulation to the arterial circulation through a right-to-left shunt. Therefore, PFO closure to eradicate the right-to-left shunt has been proposed as an intervention to reduce PFO-related stroke. Percutaneous PFO closure devices have been in use for many years. However, up until recently, clinical trials did not show significantly lower rates of recurrent stroke with PFO closure compared to standard medical therapy alone. (3-5) A sub-group analysis of the RESPECT (Randomized Evaluation of Recurrent Stroke Comparing PFO Closure to Established Current Standard of Care Treatment) trial showed significant reduction of stroke recurrence in patients with larger sized PFOs and atrial septal aneurysm. (6) The latest randomized controlled trials investigating the benefit of PFO closure utilized stricter inclusion criteria, in which patients were only eligible for closure if they had PFOs with an associated large interatrial shunt or atrial septal aneurysm, cortical stroke, and were <60 years old. (7-9) These trials concluded that the rate of recurrent stroke was significantly lower with closure, with one stroke avoided at 2 years for every 24 treated patients. (7)However, due to feasibility, these trials used an open label design where the patients and the treating clinicals were aware of the treatment assignment, increasing the risk of bias.