Future Outlook
Three randomized trials are currently registered and recruiting patients, with the aim to contribute to our understanding of safety and efficacy of PFO closure when compared with medical therapy:
Summary
Randomized clinical trials and the large number of meta-analyses have been performed to further inform the discussion on the effectiveness of percutaneous PFO closure in the secondary prevention of cryptogenic stroke and embolism. While the available evidence points towards a potential treatment effect in favor of percutaneous PFO closure, there still remain substantial uncertainties. In addition to device-specific differences that may impact on clinical outcomes owing to differences in closure success and predisposition for thrombus formation and atrial arrhythmias, appropriate patient selection remains crucial. Although not specifically examined in dedicated randomized trials, patients with certain echocardiographic high-risk criteria, such as atrial septal aneurysm and other anatomical and functional characteristics of the PFO, which are associated with increased shunt size, as well as the presence of an Eustachian valve or a Chiari network, contribute to an increased risk of recurrent embolic events and may benefit most from percutaneous PFO closure. However, additional randomized studies comparing PFO closure with medical therapy are unlikely to answer these open questions conclusively, given the low rates of recurrent events, and unrealistically large treatment effect assumptions used for sample size considerations.