All patients
PFO is not associated with higher risk of recurrent stroke or death in medically treated patients. However, in patients aged under 60 years with PFO and atrial septal aneurysm, the risk of recurrent stroke is higher.
Asymptomatic with small defect
PFO is a very common and often incidental finding with an excellent prognosis. No formal studies are available.
Large PFO and previous stroke
Risk of recurrent stroke with no other obvious cause is three times higher in patients with PFO and six times higher in patients with PFO and atrial septal aneurysm (3% per year).[12]Mas JL, Zuber M. Recurrent cerebrovascular events in patients with patent foramen ovale, atrial septal aneurysm, or both and cryptogenic stroke or transient ischemic attack. Am Heart J. 1995 Nov;130(5):1083-8.
http://www.ncbi.nlm.nih.gov/pubmed/7484740?tool=bestpractice.com
[35]Bogousslavsky J, Garazi S, Jeanrenaud X, et al. Stroke recurrence in patients with patent foramen ovale: the Lausanne study. Neurology. 1996 May;46(5):1301-5.
http://www.ncbi.nlm.nih.gov/pubmed/8628471?tool=bestpractice.com
[36]Stone DA, Godard J, Corretti MC, et al. Patent foramen ovale: association between the degree of shunt by contrast transesophageal echocardiography and the risk of future ischemic neurologic events. Am Heart J. 1996 Jan;131(1):158-61.
http://www.ncbi.nlm.nih.gov/pubmed/8554004?tool=bestpractice.com
After percutaneous closure
Risk of recurrent stroke is low but not negligible.[37]Hung J, Landzberg MJ, Jenkins KJ, et al. Closure of patent foramen ovale for paradoxical emboli: intermediate-term risk of recurrent neurological events following transcatheter device placement. J Am Coll Cardiol. 2000 Apr;35(5):1311-6.
http://www.ncbi.nlm.nih.gov/pubmed/10758974?tool=bestpractice.com
[38]Homma S, Di Tullio MR, Sacco RL, et al. Surgical closure of patent foramen ovale in cryptogenic stroke patients. Stroke. 1997 Dec;28(12):2376-81.
http://stroke.ahajournals.org/content/28/12/2376.full
http://www.ncbi.nlm.nih.gov/pubmed/9412617?tool=bestpractice.com