Abstract WP248: PFO Shunting is Associated With Increased Long-Term Risk of Dementia

Background: Right-to-left interatrial shunting through a patent foramen ovale (PFO) has been associated with white matter lesions in literature and in our data. Since white matter lesions, particularly those in the periventricular and subcortical regions, increase the risk of cognitive impairment, we investigate the relationship between PFO shunting and dementia. Method: 1078 consecutive PFO stroke patients were prospectively recruited in accordance with IRB protocol. No patient had diagnosis of dementia prior to initial stroke. PFO shunt size was evaluated by echocardiography with saline contrast. Cognitive status and recurrent events were followed for up to 11 years. Result: 27 patients (2.50%) developed vascular cognitive impairment and dementia over 11 years. As expected, dementia patients were older (p<0.001) and were more likely to have hypertension (p<0.001) and hyperlipidemia (p=0.001) (Table 1). Notably, the dementia patients were also more likely to have a large PFO shunt (22.2% vs 8.3%, p=0.023). The association of PFO shunt and dementia remained robust (Odds ratio: 3.07; 95% CI: 1.11~8.55; p=0.031) after adjusting for important traditional risk factors (age, hypertension, hyperlipidemia, diabetes). But PFO risk factors (hypermobile septum, atrial septal aneurysm) that enhance PFO shunting remain significant (Table 2). Conclusion: Our study provides support for the hypothesis that the presence of large PFO right-to-left shunting is associated with increased risk of later dementia. We previously reported that PFO shunting enables vasoactive factors to stay elevated in circulation and to contribute to cerebrovascular dysfunction. We hypothesize here that prolonged exposure to PFO shunting may lead to cognitive decline. Further studies assessing PFO shunt size, dementia severity, and other confounders in a non-stroke PFO cohort are ongoing to validate these findings.