Residual Shunt After Patent Foramen Ovale Closure and Long-Term Stroke Recurrence: A Prospective Cohort Study.

BACKGROUND Residual shunt is observed in up to 25% of patients after patent foramen ovale (PFO) closure, but its long-term influence on stroke recurrence currently is unknown. OBJECTIVE To investigate the association of residual shunt after PFO closure with the incidence of recurrent stroke and transient ischemic attack (TIA). DESIGN Prospective cohort study comparing stroke or TIA recurrence in patients with and without residual shunt after PFO closure. SETTING Single hospital center. PARTICIPANTS 1078 consecutive patients (mean age, 49.3 years) with PFO-attributable cryptogenic stroke who were undergoing percutaneous PFO closure were followed for up to 11 years. MEASUREMENTS Residual shunt was evaluated by transthoracic echocardiography with saline contrast. Primary outcome was a composite of the first recurrent ischemic stroke or TIA after PFO closure. RESULTS Compared with complete closure, the presence of residual shunt after PFO closure was associated with an increased incidence of recurrent stroke or TIA: 2.32 versus 0.75 events per 100 patient-years (hazard ratio [HR], 3.05 [95% CI, 1.65 to 5.62]; P < 0.001). This result remained robust after adjustment for important covariates, namely age; study period; device; presence of atrial septal aneurysm, hypertension, hyperlipidemia, diabetes, hypercoagulability, or hypermobile septum; and medication use (HR, 3.01 [CI, 1.59 to 5.69]; P < 0.001). Further stratification based on shunt size revealed that moderate or large residual shunts were associated with a higher risk for stroke or TIA recurrence (HR, 4.50 [CI, 2.20 to 9.20]; P < 0.001); the result for small residual shunts was indeterminate (HR, 2.02 [CI, 0.87 to 4.69]; P = 0.102). LIMITATION Nonrandomized study with potential unmeasured confounding. CONCLUSION Among patients undergoing PFO closure to prevent future stroke, the presence of residual shunt, particularly a moderate or large residual shunt, was associated with an increased risk for stroke or TIA recurrence. PRIMARY FUNDING SOURCE National Institutes of Health.