Patent foramen ovale: the evident paradox between the apparently simple treatment and the really complex pathophysiology.

The simplicity and high safety profile of the new generation family of devices, and in particular of the last generation of occluder device, has given impetus to the diffusion of patent foramen ovale (PFO) transcatheter closure, which appears to be very simple and safe. Paradoxically, the pathophysiology of PFO is all but simple and the fact that many details of PFO-mediated syndromes are not yet fully understood is taken as proof of improper PFO closure by skeptics. However, on careful in-depth analysis of this apparently straightforward operation, many potential problems can be found at different stages; from a technical point of view, nickel toxicity, the possibility of thrombus formation, presence of residual shunt, malpositioning, and erosions are still active and real problems, whereas the pathophysiology of right-to-left shunt, role of coagulation abnormalities, significance of atrial septal aneurysm and other sources of shunt remain unresolved issues. Multidisciplinary task forces with PFO-related syndromes surveillance programs and highly-skilled interventional cardiologists are likely to increase the effectiveness and safety of PFO management.