Meissner I et al. (2005) Patent foramen ovale: innocent or guilty? Evidence from a prospective population-based study. J Am Coll Cardiol 47: 440–445

Data supporting a link between patent foramen ovale (PFO) and stroke have generated controversy, partly because studies have not accounted for age or comorbidity and inappropriate controls have been used. Following the Stroke Prevention Assessment of Risk in a Community (SPARC) study, Meissner et al. have assessed whether PFO is an independent risk factor for stroke and atrial septal aneurysm (ASA) in the general population.

A total of 585 individuals aged at least 45 years were randomly selected from the SPARC study cohort. Participants were screened with transesophageal echocardiography for PFO and ASA. The incidence of cerebrovascular-related deaths, ischemic stroke and transient ischemic attacks was recorded over a median follow-up of 5.1 years.

PFO was detected in 140 (24.3%) of 577 individuals, confirming that this heart defect is common in the general population. ASA was found in 11 (1.9%) individuals, and 6 (4.3%) people with PFO also had ASA. At follow-up, a cerebrovascular event had occurred in 12 individuals with PFO, and in 41 study participants in total. By use of Kaplan–Meier analysis, the investigators ascertained that the incidence of cerebrovascular events over 5 years was similar in individuals with or without PFO, indicating that PFO is not linked with an elevated risk of stroke in the general population. Although there was a trend toward increased risk of stroke for people with ASA, the authors note that larger studies are required to confirm this potential association.