Since Lechat’s and Webster’s seminal reports, the statistical association of cryptogenic stroke and patent foramen ovale (PFO) has intrigued both cardiologists and neurologists. Growing technical experience and improved percutaneous devices have encouraged cardiologists increasingly to close PFOs. Nevertheless, the indication for this procedure often remains problematic. Clearly, paradoxical embolism through a PFO is a well recognised complication of deep venous thrombosis, especially in the context of pulmonary embolism with its attending increase in right sided pressures. This scenario, however, is relatively rare. In contrast, the true importance of paradoxical embolism through a PFO in other circumstances remains unclear.

In this mini-symposium, the importance of PFO and the “case for closure” is expertly reviewed from different angles. Fausto Pinto discusses the echocardiographic diagnosis of patent foramen ovale; Pierre Amarenco reviews the observational basis for the imputed causality between PFO and cerebral ischaemia; and Bernhard Meier explains the interventional closure procedure and the devices.