Prevalence of PFO in patients with cryptogenic events compared with patients with events of known cause
Meta-analyses of the prevalence of PFO in patients with cryptogenic events compared with patients with events of known cause, stratified by imaging modalities, (A) overall and (B) in older patients, according to study author's definition. PFO=patent foramen ovale. OR=odds ratio. Bubble-TCD=contrast-enhanced transcranial Doppler. OXVASC=Oxford Vascular Study. *Age cutoff points for the older group in different studies ranged between 40 and 60 years.