We thank Dr Spence for his comment on our article on stroke and patent foramen ovale (PFO) and for indicating their analysis of a large cohort of patients with cryptogenic stroke and PFO. Dr Spence and coworkers provide a valuable table of factors that are significantly more common in patients with cryptogenic stroke and PFO than in patients without PFO. However, most often, such clinical clues are missing in an individual patient. In the individual patient, the likelihood of PFO being a chance finding can be calculated with a complicated formula (1), which is nothing else than 1 divided by the odds ratio of an association of the cryptogenic stroke and the PFO as given in our article (2).
References
1.
Alsheikh-AliAAThalerDEKentDM. Patent foramen ovale in cryptogenic stroke: incidental or pathogenic?Stroke2009; 40:2349–55.
2.
MattleHPMeierBNedeltchevK. Prevention of stroke in patients with patent foramen ovale. Int J Stroke2010; 5:92–102.
