Patent foramen ovale: innocent or guilty? Evidence from a prospective population-based study.
OBJECTIVE
We sought to determine the association between patent foramen ovale (PFO), atrial septal aneurysm (ASA), and stroke prospectively in a unselected population sample.


BACKGROUND
The disputed relationship between PFO and stroke reflects methodologic weaknesses in studies using invalid controls, unblinded transesophageal echocardiography examinations, and data that are unadjusted for age or comorbidity.


METHODS
The use of transesophageal echocardiography to identify PFO was performed by a single echocardiographer using standardized definitions in 585 randomly sampled, Olmsted County (Minnesota) subjects age 45 years or older participating in the Stroke Prevention: Assessment of Risk in a Community (SPARC) study.


RESULTS
A PFO was identified in 140 (24.3%) subjects and ASA in 11 (1.9%) subjects. Of the 140 subjects with PFO, 6 (4.3%) had an ASA; of the 437 subjects without PFO, 5 had an ASA (1.1%, two-sided Fisher exact test, p = 0.028). During a median follow-up of 5.1 years, cerebrovascular events (cerebrovascular disease-related death, ischemic stroke, transient ischemic attack) occurred in 41 subjects. After adjustment for age and comorbidity, PFO was not a significant independent predictor of stroke (hazard ratio 1.46, 95% confidence interval 0.74 to 2.88, p = 0.28). The risk of a cerebrovascular event among subjects with ASA was nearly four times higher than that in those without ASA (hazard ratio 3.72, 95% confidence interval 0.88 to 15.71, p = 0.074).


CONCLUSIONS
These prospective population-based data suggest that, after correction for age and comorbidity, PFO is not an independent risk factor for future cerebrovascular events in the general population. A larger study is required to test the putative stroke risk associated with ASA.
Meissner
Irene
I
Department of Neurology, Mayo Clinic, Rochester, Minnesota 55905, USA. meissner.irene@mayo.edu
Khandheria
Bijoy K
BK
Heit
John A
JA
Petty
George W
GW
Sheps
Sheldon G
SG
Schwartz
Gary L
GL
Whisnant
Jack P
JP
Wiebers
David O
DO
Covalt
Jody L
JL
Petterson
Tanya M
TM
Christianson
Teresa J H
TJ
Agmon
Yoram
Y
D000368:Aged; D002318:Cardiovascular Diseases / Q000453:epidemiology; D015897:Comorbidity; D017548:Echocardiography, Transesophageal; D005260:Female; D006344:Heart Septal Defects, Atrial / Q000150:complications* / Q000000981:diagnostic imaging / Q000453:epidemiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D016016:Proportional Hazards Models; D011446:Prospective Studies; D012307:Risk Factors; D020521:Stroke / Q000209:etiology* / Q000517:prevention & control; D020246:Venous Thrombosis / Q000453:epidemiology