Percutaneous Closure of Patent Foramen Ovale and Atrial Septal Defect

To the Editor: In their Research Letter, Dr Opotowsky and colleagues¹ reported an increase in percutaneous closure of interatrial defects. There are a number of points that we believe need to be considered in interpreting the data presented in their article.

Patent foramen ovale (PFO) and atrial septal defect (ASD) were classified together in the analysis, so specific comment on the indication for closure should be cautious. In addition, the observation that the rate of interatrial shunt closure has increased disproportionate to coronary revascularization following the introduction of stents needs to be viewed in context. This is due in part to far fewer PFO/ASD closures being performed in comparison with coronary revascularization at the commencement of the relevant periods. This increase is also likely to be magnified by significant improvements in equipment, devices, operator training, and lesion identification.

With regard to PFO closure, the US Food and Drug Administration (FDA) recommendations reflect the lack of any evidence to support the superiority of mechanical closure over medical therapy.² However, they do not take into account the heterogeneity of patient presentations and clinical issues. Indeed, the relatively low recurrence rate of stroke in patients with prior cryptogenic stroke on medical therapy makes it very difficult to demonstrate the superiority of an alternate strategy (due to the large number of patients required to power such a study and the duration of follow-up needed to detect recurrence).

Pending adequately powered clinical studies, it is important to identify and offer device closure for cryptogenic stroke in patients at high risk. In the absence of definitive data, it appears that not all PFOs are identical and the concept of a PFO phenotype with poor prognosis needs to be considered in treating patients.³ While continuing to facilitate patient enrollment into trials investigating this problem, it is equally important to use clinical judgment about who may benefit from device closure.